Effect of quercetin on the protein-substrate interactions in SIRT6: Insight from MD simulations

SIRT6 is of interest for its promising effect in the treatment of aging-related diseases. Studies have shown quercetin (QUE) and its derivatives have varying degrees of effect on the catalytic effect of SIRT6. In the research, the effect of QUE on the protein-substrate interaction in the SIRT6-mediated mono-ADP ribosylation system was investigated by conventional molecular dynamics (MD) simulations combined with MM/PBSA binding free energy calculations. The results show that QUE can bind stably to SIRT6 with the binding energy of -22.8 kcal/mol and further affect the atomic interaction between SIRT6 and NAD+ (or H3K9), resulting in an increased affinity between SIRT6-NAD+ and decreased SIRT6-H3K9 binding capacity. At the same time, the binding of QUE can also alter some structural characteristics of the protein, with large shifts occurring in the residue regions involving the N-terminal (residues 1-27), Rossmann fold regions (residues 55-92), and ZBD (residues 164-179). Thus, QUE shows great potential as a scaffold for the design of novel potent SIRT6 modulators.

[Epidemiological and spatial-temporal clustering characteristics of pertussis in Hebei Province from 2013 to 2022]

Objective: To analyze the spatial-temporal epidemiological characteristics of pertussis from 2013 to 2022 in Hebei Province and to provide a reference for improving prevention and control measures. Methods: Based on the data of pertussis reported in Hebei Province during 2013-2022 to analyze the popular characteristic, the ArcGIS 10.8 software was used to construct a ring map and to perform spatial autocorrelation analysis; the SaTScan 10.1 software was used for spatial-temporal scan statistics. Results: There were 6 715 cases of the cumulative report in Hebei Province from 2013 to 2022 without death. The annual report incidence was 0.90/100 000. The overall incidence rate showed an upward trend from 2013 to 2019, and during 2020-2021, it showed a sharp decline, but in 2022, it showed a sharp increase. Summer and autumn are the peak seasons of the epidemic. The incidence was highest in age group <1 year (48.67%), and the lowest age group in age group ≥15 years (0.45%) and mainly scattered children (78.03%); the incidence about men is higher than women. Spatial autocorrelation analysis showed that the onset of pertussis has spatial clustering, and high-high clusters were found in Langfang, Baoding, and Cangzhou, the top three countries with reported incidence. The area covered by a low-low cluster was consistent with the distribution of the corresponding low-incidence areas in this study. Space-time scan detects five statistically significant areas, and three zones were concentrated in 2022. Conclusions: The incidence of pertussis in Hebei had obvious season, population, and area-specific differences. There was obvious spatiotemporal and clustering, so the control of key areas should target the characteristics of time and space.

[Efficacy and safety of allogeneic hematopoietic stem cell transplantation for the treatment of primary myelofibrosis]

Objective: To evaluate the efficacy and safety of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for the treatment of primary myelofibrosis (PMF) patients. Methods: A total of 14 cases of PMF who underwent allo-HSCT from December 2008 to December 2022 were analyzed retrospectively, including 8 males and 6 females with a median age [M(Q1, Q3)]of 36 (24, 42) years. Three-year overall survival (OS), disease free survival (DFS), cumulative incidence of relapse (CIR), transplantation-related mortality (TRM) were analyzed. Meanwhile, the complications were followed up by telephone and outpatient appointments for 49.6 (9.0,93.1) months. Results: All patients received myeloablative conditioning regimens (MAC). All patients had successful engraftment, and the median time of neutrophils and platelet engraftment were 13.5 (11.8, 18.0) days and 19.5 (13.5, 24.5) days, respectively. Ⅱ-Ⅳ acute graft versus host disease (GVHD) occurred in 3 cases, while chronic GVHD in 8 cases. The rate of 3-year OS,DFS,CIR and TRM were (92.9±6.9)%, (76.0±12.2)%, (38.6±2.7)% and (7.1±0.5)% respectively after a median follow-up time of 1 489.0 (270.3,2 794.8) days. Two patients died from treatment-related complications, one of which died 39 days after transplantation due to heart failure caused by severe anemia, the other patient died 6 years after relapse due to pulmonary infection. Conclusion: Allo-HSCT can be used as a safe and effective approach to treat PMF.

Theoretical Investigations on the Rh(III)-Catalyzed Oxidative C-H Activation/Annulation of Salicylaldehydes with Masked Enynes: Mechanism Insights and Regioselectivity Origins

The mechanism underlying the rhodium(III)-catalyzed reaction of the C-H alkenylation/annulation reaction of salicylaldehydes with enynes has been thoroughly investigated using DFT calculations. Based on mechanistic studies, our focus primarily lies on the regioselectivity of asymmetric alkynes inserting into the Rh-C bond and the involvement of the auxiliary group OAc- in these reactions. Our theoretical study uncovers that, with acetate assistance, a stepwise SN2' cyclization, 1,3-Rh migration, β-H elimination, and reductive elimination process occur. Furthermore, we also explore the role of substitution at Cα (CH3 vs H) in the reaction. As demonstrated in this work, these findings are applicable to other related reactions.

[Efficacy and feasibility of catheter-based adrenal ablation on Cushing's syndrome associated hypertension]

Objective: To explore the value of catheter-based adrenal ablation in treating Cushing's syndrome (CS)-associated hypertension. Methods: A clinical study was conducted in patients with CS, who received catheter-based adrenal ablation between March 2018 and July 2023 in Daping Hospital. Parameters monitored were blood pressure (outpatient and 24-hour ambulatory), body weight, clinical characteristics, serum cortisol and adrenocorticotropic hormone (ACTH) at 8 am, 24-hour urinary free cortisol (24 h UFC), fasting blood glucose and postoperative complications. Procedure effectiveness was defined as blood pressure returning to normal levels (systolic blood pressure<140 mmHg (1 mmHg=0.133 kPa) and diastolic blood pressure<90 mmHg), cortisol and 24 h UFC returning to normal and improvement of clinical characteristics. The parameters were monitored during follow up in the outpatient department at 1, 3, 6, and 12 months after catheter-based adrenal ablation. Results: A total of 12 patients (aged (40.0±13.2) years) were reviewed. There were 5 males, with 5 cases of adenoma and 7 with hyperplasia from imaging studies. Catheter-based adrenal ablation was successful in all without interruption or surgical conversion. No postoperative complication including bleeding, puncture site infection, adrenal artery rupture or adrenal bleeding was observed. The mean follow up was 28 months. Compared to baseline values, body weight declined to (59.48±11.65) kg from (64.81±10.75) kg (P=0.008), fasting blood glucose declined to (4.54±0.83) mmol from (5.53±0.99) mmol (P=0.044), outpatient systolic blood pressure declined to (128±21) mmHg from (140±19) mmHg (P=0.005), diastolic blood pressure declined to (78±10) mmHg from (86±11) mmHg (P=0.041), and the mean ambulatory daytime diastolic blood pressure declined to (79±12) mmHg from (89±8) mmHg (P=0.034). Catheter-based adrenal ablation in 8 patients was defined as effective with their 24 h UFC significantly reduced after the procedure (1 338.41±448.06) mmol/L from (633.66±315.94) mmol/L, P=0.011). The change of 24 h UFC between the effective treatment group and ineffective group was statistically significant (P=0.020). The postoperative systolic blood pressure in the treated adenoma group was significantly lower than those of hyperplasia group (112±13) mmHg vs. (139±20) mmHg, P=0.026). Conclusions: For patients with CS-associated hypertension who are unwilling or unable to undergo surgical treatment, catheter-based adrenal ablation could improve the blood pressure and cortisol level. Catheter-based adrenal ablation could be a safe, effective, and minimally invasive therapy. However, our results still need to be validated in further large-scale studies.

[Study on clearance of chlorfenapyr via blood purification (a case analysis)]

This paper analyzed the clinical data of a patient with acute oral emamectin·chlorfenapyr poisoning, and discussed the effect of blood purification therapy on chlorfenapyr poisoning. Chlorfenapyr was detected in the blood, urine, ultrafiltrate and plasma exchange fluid of the patient, and the concentrations of chlorfenapyr poison gradually decreased with time. Blood purification has a certain effect on chlorfenapyr, and early blood purification may be an effective measure to treat chlorfenapyr poisoning.

GABAergic Neurons in the Nucleus Accumbens are Involved in the General Anesthesia Effect of Propofol

The mechanism underlying the hypnosis effect of propofol is still not fully understood. In essence, the nucleus accumbens (NAc) is crucial for regulating wakefulness and may be directly engaged in the principle of general anesthesia. However, the role of NAc in the process of propofol-induced anesthesia is still unknown. We used immunofluorescence, western blotting, and patch-clamp to access the activities of NAc GABAergic neurons during propofol anesthesia, and then we utilized chemogenetic and optogenetic methods to explore the role of NAc GABAergic neurons in regulating propofol-induced general anesthesia states. Moreover, we also conducted behavioral tests to analyze anesthetic induction and emergence. We found out that c-Fos expression was considerably dropped in NAc GABAergic neurons after propofol injection. Meanwhile, patch-clamp recording of brain slices showed that firing frequency induced by step currents in NAc GABAergic neurons significantly decreased after propofol perfusion. Notably, chemically selective stimulation of NAc GABAergic neurons during propofol anesthesia lowered propofol sensitivity, prolonged the induction of propofol anesthesia, and facilitated recovery; the inhibition of NAc GABAergic neurons exerted opposite effects. Furthermore, optogenetic activation of NAc GABAergic neurons promoted emergence whereas the result of optogenetic inhibition was the opposite. Our results demonstrate that NAc GABAergic neurons modulate propofol anesthesia induction and emergence.

Investigating the influence of substituent groups in TTM based radicals for the excitation process: a theoretical study

Tri-(2,4,6-trichlorophenyl)methyl (TTM) based radicals can be promising in providing relatively high fluorescence quantum efficiency. In this study, we have evaluated the photoluminescence properties of a series of TTM-based radicals by means of DFT and TD-DFT methods. The optimized structures of the ground states (D0) and the first excited states (D1) of all the radicals are calculated and the computed emission bands are comparable with previous experimental results. knr is determined from transition dipole moments (μ12) and the energy gaps between D0 and D1 (ΔE), both of which can be regulated by the conjugated structures from the substituent groups. knr was derived from the mode-averaging method and is consistent with the experimental results. Factors influencing kr and knr, including the potential energy differences (ΔG0), the vibrational reorganization energies (λ) and the electron coupling term (Hab), are discussed. By comparing kr and knr in solvents with different polarities (cyclohexane, toluene, and chloroform), TTM based radicals in cyclohexane exhibit the most promising fluorescence efficiencies. Besides, two substituted radicals, namely 2Br-TTM-3PCz and 2F-TTM-3PCz, have been fabricated. The results show that fluorine atoms are able to increase ΔG0 and a considerably small knr has been predicted. We expect that our calculation can benefit the design of light-emitting molecules in further experiments.

The molecular mechanism of non-covalent inhibitor WU-04 targeting SARS-CoV-2 3CLpro and computational evaluation of its effectiveness against mainstream coronaviruses

There is an urgent need for highly effective therapeutic agents to interrupt the continued spread of SARS-CoV-2. As a pivotal protease in the replication process of coronaviruses, the 3CLpro protein is considered as a potential target of drug development to stop the spread and infection of the virus. In this work, molecular dynamics (MD) simulations were used to elucidate the molecular mechanism of a novel and highly effective non-covalent inhibitor, WU-04, targeting the SARS-CoV-2 3CLpro protein. The difference in dynamic behavior between the apo-3CLpro and the holo-3CLpro systems suggests that the presence of WU-04 inhibits the motion amplitude of the 3CLpro protein relative to the apo-3CLpro system, thus maintaining a stable conformational binding state. The energy calculations and interaction analysis show that the hot-spot residues Q189, M165, M49, E166, and H41 and the warm-spot residues H163 and C145 have a strong binding capacity to WU-04 by forming multiple hydrogen bonds and hydrophobic interactions, which stabilizes the binding of the inhibitor. After that, the resistance of WU-04 to the six SARS-CoV-2 variants (Alpha, Beta, Gamma, Delta, Lambda, and Omicron) and two other mainstream coronavirus (SARS-CoV and MERS-CoV) 3CLpro proteins was further investigated. Excitingly, the slight difference in energy values relative to the SARS-CoV-2 system indicates that WU-04 is still highly effective against the coronaviruses, which becomes crucial evidence that WU-04 is a pan-inhibitor of the 3CLpro protein in various SARS-CoV-2 variants and other mainstream coronaviruses. The study will hopefully provide theoretical insights for the future rational design and improvement of novel non-covalent inhibitors targeting the 3CLpro protein.

[The impact of human umbilical cord-derived mesenchymal stem cells on the pancreatic function of type 2 diabetic mice and their regulatory role on NLRP3 inflammasomes]

Objective: To investigate the effect and regulation of umbilical cord-derived mesenchymal stem cells (UC-MSCs) on islets function and NOD-like receptor family, pyrin domain containing 3 (NLRP3) and autophagy in type 2 diabetic mellitus (T2DM) mice. Methods: Experimental study. Twenty, 8-week-old, male C57BL/6J mice were selected and divided into a normal control group (n=5) and a high-fat feeding modeling group (n=15). The model of T2DM was established by high-fat feeding combined with intraperitoneal injection of low-dose streptozotocin. After successful modeling, those mice were divided into a diabetes group (n=7) and a UC-MSCs treatment group (n=7). The UC-MSCs treatment group was given UC-MSCs (1×106/0.2 ml phosphate buffer solution) by tail vein infusion once a week for a total of 4 weeks; the diabetes group was injected with the same amount of normal saline, and the normal control group was not treated. One week after the treatment, mice underwent intraperitoneal glucose tolerance tests and intraperitoneal insulin tolerance tests, and then the mice were sacrificed to obtain pancreatic tissue to detect the expressions of interleukin-1β (IL-1β) and pancreatic and duodenal homeobox 1 (PDX-1) by immunofluorescence. The bone marrow-derived macrophages were stimulated with lipopolysaccharide and adenosine triphosphate (experimental group) in vitro, then co-cultured with UC-MSCs for 24 h (treatment group). After the culture, enzyme-linked immunosorbent assay was used to detect the secretion level of IL-1β in the supernatant, and immunofluorescence staining was used to detect the expression of NLRP3 inflammasome, and related autophagy proteins. Statistical analysis was performed using unpaired one-way analysis of variance, repeated measure analysis of variance. Results: In vivo experiments showed that compared with the diabetes group, the UC-MSCs treatment group partially repaired islet structure, improved glucose tolerance and insulin sensitivity (all P<0.05), and the expression of PDX-1 increased and IL-1β decreased in islets under confocal microscopy. In vitro experiments showed that compared with the experimental group, the level of IL-1β secreted by macrophages in the treatment group was decreased [(85.9±74.6) pg/ml vs. (883.4±446.2) pg/ml, P=0.001], the expression of NLRP3 inflammasome and autophagy-related protein P62 was decreased, and the expressions of microtubule-associated protein 1 light chain 3β (LC3) and autophagy effector Beclin-1 were increased under confocal microscopy. Conclusions: UC-MSCs can reduce the level of pancreatic inflammation in T2DM mice, preserving pancreatic function. This might be associated with the ability of UC-MSCs to inhibit the activity of NLRP3 inflammasomes in macrophages and enhance autophagy levels.

[Pharmacokinetics and pharmacodynamics of antibiotics in septic children treated with extracorporeal membrane oxygenation]

Objective: To investigate the characteristics of pharmacokinetic (PK) and pharmacodynamic (PD) parameters of antibacterial agents in children with sepsis treated by extracorporeal membrane oxygenation (ECMO). Methods: In this prospective cohort study, 20 children with sepsis (confirmed or suspected) who were treated with ECMO and antimicrobial in the Department of Critical Medicine of Hunan Children's Hospital from March 2021 to December 2022 were enrolled as the ECMO group. Through therapeutic drug monitoring (TDM), the PK-PD parameters of antibacterial agents were analyzed. Twenty five children with sepsis in the same department who were treated with vancomycin but no ECMO at the same time were enrolled as the control group. The individual PK parameters of vancomycin were calculated by Bayesian feedback method. The PK parameters in the two groups were compared, and the correlation between trough concentration and area under the curve (AUC) was analyzed. Wilcoxon rank sum test was used for inter group comparison. Results: Twenty patients in the ECMO group, included 6 males and 14 females, with an onset age of 47 (9, 76) months. In the ECMO group, 12 children (60%) were treated with vancomycin, and the trough concentration was less than 10 mg/L in 7 cases, 10-20 mg/L in 3 cases, and >20 mg/L in 2 cases; AUC/minimum inhibitory concentration (MIC) (MIC=1 mg/L)<400 was in 1 case, 400-600 in 3 cases, and >600 in 8 cases. Among the 11 children (55%) who were treated with β-lactam antibiotics, there were 10 cases with drug concentration at 50% dosing interval (C_T50)>4 MIC and 9 cases with trough concentration>MIC, both C_T50 and trough concentration of cefoperazone reached the target. Among the 25 cases of control group, 16 were males and 9 females, with an onset age of 12 (8, 32) months. There was a positive correlation between vancomycin trough concentration and AUC (r²=0.36, P<0.001). The half-life of vancomycin and the 24-hour AUC (AUC_{0-24 h}) in the ECMO group were higher than those in the control group (5.3 (3.6, 6.8) vs. 1.9 (1.5, 2.9) h, and 685 (505, 1 227) vs. 261 (210, 355) mg·h/L, Z=2.99, 3.50, respectively; both P<0.05), and the elimination rate constant and clearance rate was lower than those in the control group (0.1 (0.1, 0.2) vs. 0.4 (0.2, 0.5), 0.7 (0.5, 1.3) vs. 2.0 (1.1, 2.8) L/h, Z=2.99, 2.11, respectively; both P<0.05). Conclusion: The PK-PD parameters in septic children treated by ECMO varied with a longer half-life, higher AUC_{0-24 h}, lower elimination rate constant and clearance rate.

[Posterior cervical pedicle screw rod short-segment internal fixation for the treatment of atlantoaxial fracture and dislocation]

OBJECTIVE

To investigate the clinical efficacy of posterior cervical pedicle screw short-segment internal fixation for the treatment of atlantoaxial fracture and dislocation.

METHODS

The clinical data of 60 patients with atlantoaxial vertebral fracture and dislocation underwent surgery between January 2015 and January 2018 were retrospectively analyzed. The patients were divided into study group and control group according to different surgical methods. There were 30 patients in study group, including 13 males and 17 females, with an average age of (39.32±2.85) years old, were underwent short-segment internal fixation with posterior cervical pedicle screws. There were 30 patients in control group, including 12 males and 18 females, with an average age of (39.57±2.90) years old, were underwent posterior lamina clip internal fixation of the atlas. The operation time, intraoperative blood loss, postoperative ambulation time, hospitalization time and complications between two groups were recorded and compared. The pain visual analogue scale(VAS), Japanese Orthopedic Association(JOA) score of neurological function, and fusion status were evaluated between two groups.

RESULTS

All patients were followed up for at least 12 months. The study group was better than control group in operation time, intraoperative blood loss, postoperative off-bed activity time, and hospital stay (P=0.000). One case of respiratory tract injury occurred in study group. In control group, 2 cases occurred incision infection, 3 cases occurred respiratory tract injury, and 3 cases occurred adjacent segmental joint degeneration. The incidence of complications in study group was lower than that in control group (χ²=4.705, P=0.030). At 1, 3, 7 days after operation, VAS of study group was lower than that of control group(P=0.000). At 1, 3 months after operation, JOA score of study group was higher than that of control group(P=0.000). At 12 months after operation, all the patients in the study group achieved bony fusion. In control group, there were 3 cases of poor bony fusion and 3 cases of internal fixation fracture, the incidence rate was 20.00%(6/30). The difference between two groups was statistically significant (χ²=4.629, P=0.031).

CONCLUSION

Posterior cervical short-segment pedicle screw fixation for atlantoaxial fracture and dislocation has the advantages of less trauma, shorter operation time, fewer complications, and less pain, and can promote the recovery of nerve function as soon as possible.

In silico design of miniprotein to inhibit SARS-CoV-2 variant Omicron spike protein

Omicron is a novel variant of SARS-CoV-2 that is currently spreading globally as the dominant strain. The virus first enters the host cell through the receptor binding domain (RBD) of the spike protein by interacting with the angiotensin-converting enzyme 2 (ACE2). Thus, the RBD protein is an ideal target for the design of drugs against the Omicron variant. Here, we designed several miniprotein inhibitors in silico to combat the SARS-CoV-2 Omicron variant using single- and double-point mutation approaches, based on the structure of the initial inhibitor AHB2. Also, two parallel molecular dynamics (MD) simulations were performed for each system to reproduce the calculated results, and the binding free energy was evaluated with the MM/PBSA method. The evaluated values showed that all inhibitors, including AHB2, M7E, M7E + M43W, and M7E + M43Y, were energetically more beneficial to the binding with the RBD than ACE2. In particular, the mutant inhibitor M7E + M43Y possessed the highest binding affinity to RBD and was selected as the most promising "best" inhibitor among all inhibitors. In addition, the combination of multiple analysis methods, such as free energy landscape analysis (FEL), principal component analysis (PCA), dynamic cross-correlation matrix analysis (DCCM), and hydrogen bond, salt bridge, and hydrophobic interaction analysis, also demonstrated that the mutations significantly affect the dynamical behavior and binding pattern of the inhibitor binding to the RBD protein. The current work suggested that miniprotein inhibitors can form stable complex structures with the RBD protein and exert a blocking or inhibitory effect on the SARS-CoV-2 variant Omicron. In conclusion, this study has identified several novel mutant inhibitors with enhanced affinity to the RBD protein, and provided potential guidance and insights for the rational design of therapeutic approaches for the new SARS-CoV-2 variant Omicron.

Mechanistic Study on CpRh(III)-Catalyzed [3 + 2] Annulation of Aniline Derivatives with Vinylsilanes: A DFT Study

The rhodium(III)-catalyzed reaction of aniline derivatives that contain a pyrimidine-directing group with vinylsilanes results in the formation of C3-substituted indoline derivatives. The reaction path and formation of the indoline product with density functional theory calculations were analyzed. This study reveals that the whole catalysis can be characterized in the following stages: (I) C-H activation via concerted metalation deprotonation, (II) 2,1-vinylsilane insertion, (III) deprotonation of the NH amide proton, (IV) the oxidation of Ag⁺, and (V) reductive elimination. These steps are kinetically and thermodynamically feasible for experimental realization under mild conditions, and the insertion step with a barrier of 22.0 kcal/mol should not only be the critical step of regioselectivity but also the rate-determining step during the whole catalysis. Computations reveal that the Ag⁺ oxidation can accelerate the reductive elimination step after the formation of natural intermediate, thus highlighting the role of Ag⁺ as a catalytic promoter for the oxidatively induced reactivity of the Rh catalyst in C3-substituted indoline synthesis.

[Influencing factors of mild cognitive impairment among the Chinese elderly: a meta-analysis]

Objective: To conduct a meta-analysis on the influencing factors of mild cognitive impairment (MCI) in the Chinese elderly. Methods: The literature related to the influencing factors of MCI in Chinese elderly population was retrieved through CNKI, Wanfang, VIP, PubMed, Embase and Web of Science databases up to March 13, 2022. Stata17.0 software was used to calculate the combined risk ratio (RR) with the 95% confidence interval (CI), test the heterogeneity, and assess the publication bias. Results: A total of 2 450 articles were retrieved, and 49 articles met the inclusion criteria, including 5 cohort studies and 44 case-control studies. Meta-analysis results showed that male (RR=0.778, 95%CI: 0.696-0.870, I²=73.1), education>6years (RR=0.428, 95%CI: 0.374-0.490, I²=86.9) and regular exercise (RR=0.496, 95%CI: 0.421-0.585, I²=81.5) were protective factors for MCI, while age≥70 years (RR=2.431, 95%CI: 2.086-2.833, I²=79.3), family history of dementia (RR=3.228, 95%CI: 2.140-4.867, I²=0.0), smoking (RR=1.214, 95%CI: 1.098-1.342, I²=78.8), alcohol consumption (RR=1.165, 95%CI: 1.047-1.297, I²=68.2), solitary living (RR=2.816, 95%CI: 2.123-3.736, I²=42.0), insomnia (RR=1.402, 95%CI: 1.093-1.799, I²=41.3), overweight/obesity (RR=1.431, 95%CI: 1.207-1.696, I²=75.9), hypertension (RR=1.731, 95%CI: 1.589-1.886, I²=67.1), hyperlipidemia (RR=1.722, 95%CI: 1.541-1.924, I²=63.9), diabetes mellitus (RR=1.495, 95%CI: 1.341-1.666, I²=71.6), cardiovascular diseases (RR=1.671, 95%CI: 1.446-1.932, I²=74.6) and cerebrovascular diseases (RR=2.309, 95%CI: 2.040-2.613, I²=76.3) were risk factors of MCI. Conclusion: The present study indicates that male, junior high school education or above and regular exercise are protective factors of MCI, while age≥70 years, family history of dementia, smoking, alcohol consumption, living alone, insomnia, overweight/obesity, hypertension, hyperlipidemia, diabetes, cardiovascular diseases and cerebrovascular diseases are risk factors of MCI.

Energy transfer across magnetopause under dawn-dusk IMFs

A parametric study on the energy transfer of the solar wind across the magnetopause entering the magnetosphere is conducted using a global magnetohydrodynamic numerical simulation. The characteristics of the mechanical and electromagnetic energy distribution under the dawn-dusk interplanetary magnetic fields (IMFs) are investigated by analyzing magnetic reconnection and viscous effect, and compared with the radial and north-south IMFs. It is shown that (1) the interactions at the magnetopause and the transfer of energy across this boundary move in relation to the IMF orientation. (2) For the duskward IMF, the mechanical energy flow clearly enters the equatorial and low-latitude regions on the dayside, and the electromagnetic energy flow has a small inflow on the equatorial and low latitudes of the dayside. A significant energy inflow appears on the dawn side in the northern hemisphere and the dusk side in the southern hemisphere near the polar cusp. (3) The energy distribution characteristics across the magnetopause under dawn-dusk IMFs are mirror symmetric about the [Formula: see text] plane. (4) For a magnetic field of 5 nT, the electromagnetic energy input under the dawn-dusk IMFs is twice as large as the mechanical energy and the electromagnetic energy under the radial IMF, which is five times as large as the electromagnetic energy during the pure northward IMF, but only half as large as the electromagnetic energy under the pure southward IMF. The mechanical energy input under dawn-dusk IMFs has the same magnitude as that under radial and north-south IMFs. The magnitude of the energy transfer rate for the dawn IMF and dusk IMF (about 3.5%) is between 1.71% for the northward IMF and 4.95% for the southward IMF, but higher than 2.22% for the radial IMF. The Akasofu-type energy-coupling formula, [Formula: see text], underestimates the energy input from the solar wind under [Formula: see text] dominated IMF.

[A case of pulmonary aspergillus infection in underground coal mine workers]

The underground environment is dark and humid, and it is easy to breed pathogenic microorganisms. A lump in the right lung of a coal mine underground transport worker was found druing occupational health examination. CT examination showed that the lump was located in the posterior segment of the upper lobe of the right lung, with point strip calcification, liquefaction necrosis, and proximal bronchial stenosis and occlusion. MRI examination FS-T(2)WI and DWI showed "target sign", annular low signal around the central high signal, and low mixed signal around the periphery, and annular high signal in the isosignal lesions on T(1)WI. Then the pulmonary aspergillus infection was confirmed by pathology.

[Survival efficacy of MDS/AML patients with TP53 abnormal received allogeneic hematopoietic stem cell transplantation]

Objective: TP53-abnormal MDS/acute myeloid leukemia (AML) patients' allogeneic hematopoietic stem cell transplantation (allo-HSCT) treatment's effectiveness and influencing factors should be studied. Methods: 42 patients with TP53 gene status change MDS/AML who underwent allo-HSCT from 2014.8.1 to 2021.7.31 at the Hematology Hospital of the Chinese Academy of Medical Sciences were the subject of a retrospective analysis. The 42 patients were divided into three groups: the TP53 deletion group (group A) , TP53 mono-alle mutation group (group B) , and TP53 multi-hit group (group C) . The differences in clinical features and prognostic factors after transplantation were analyzed. Results: There were 42 MDS/AML patients, including 21 patients with MDS, and 21 patients with AML. The median follow-up period was 34.0 (7.5-75.0) months and the median patient age at the time of transplantation was 41.5 (18-63) years old. The total OS was 66.3% (95% CI 53.4%-82.4%) in 3 years after transplantation, and EFS was 61.0% (95% CI 47.7%-78.0%) in 3 years. For 3 years after receiving hematopoietic stem cell transplantation, there were no statistically significant differences in 3-year OS and EFS in groups A, B, and C (P≥0.05) . The 3 years OS was 82.5% (95% CI 63.1%-100.0%) in group A, 60.6% (95% CI 43.5%-84.4%) in group B, and 57.1% (95% CI 30.1%-100.0%) in group C. Univariate analysis revealed that the number of co-mutant genes, pre-HSCT treatment, and disease type did not affect prognosis, while age, karyotype, co-mutation, positive blast cell before transplantation, and positive blast cell after transplantation were common prognostic factors for OS and EFS (P<0.1) . MRD levels before transplantation were found to be independent risk factors for OS (P=0.037, HR=33.40, 95% CI 1.24-901.17) in a multivariate analysis. Conclusion: Patients with MDS/AML who have TP53 mutations can benefit from allo-HSCT, but patients with complex karyotypes have a worse prognosis. Meanwhile, the final flow cytometry (FCM) monitoring blast cell test before HSCT has a certain guiding significance for prognostic assessment.

Theoretical Study on Zigzag Boron Nitride Nanowires

In this work, two kinds of BN-nanowires (BNnws): a-BNnw and d-BNnw, respectively composed of azo (N-N) and diboron (B-B) bonds, are proposed with the aid of the first-principles simulations. Their structural stabilities are carefully verified from the energetics, lattice dynamics, and thermodynamic perspectives. Similar to the other common boron nitride polymorph, the a-BNnw and d-BNnw are semiconductors with relatively wide band gaps of 3.256 and 4.631 eV at the HSE06 level, respectively. The corresponding projected DOS patterns point out that their band edges are composed of different atomic species, which can help with the separation of their excitons. The band gaps can be manipulated monotonically by axial strains within the elastic ranges. The major charge carriers are electron holes. Significantly, a-BNnw possesses very high carrier mobilities around 0.44×10⁴  cm²  V^-1  s^-1 .

Investigation on the interaction mechanism of different SARS-CoV-2 spike variants with hACE2: insights from molecular dynamics simulations

Since the COVID-19 pandemic caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), SARS-CoV-2 has evolved by acquiring genomic mutations, resulting in the recent emergence of several SARS-CoV-2 variants with improved transmissibility and infectivity relative to the original strain. An underlying mechanism may be the increased ability of the mutants to bind the receptor proteins and infect the host cell. In this work, we implemented all-atom molecular dynamics (MD) simulations to study the binding and interaction of the receptor binding domain (RBD) of the SARS-CoV-2 spike protein singly (D614G), doubly (D614G + L452R and D614G + N501Y), triply (D614G + N501Y + E484K), and quadruply (D614G + N501Y + E484K + K417T) mutated variants with the human angiotensin-converting enzyme 2 (hACE2) receptor protein in the host cell. A combination of multiple analysis approaches elucidated the effects of mutations and the extent of molecular divergence from multiple perspectives, including the dynamic correlated motions, interaction patterns, dominant motions, free energy landscape, and charge distribution on the electrostatic potential surface between the hACE2 and all RBD variants. Moreover, free energy calculations using the MM/PBSA method evaluated the binding affinity between these RBD variants and hACE2. The results showed that the D614G + N501Y + E484K variant possessed the lowest free energy value (highest affinity) compared to the D614G + N501Y + E484K + K417T, D614G + L452R, D614G + N501Y, and D614G mutants. The residue-based energy decomposition also indicated that the energy contribution of residues at the mutation site to the total binding energy was highly variable. The interaction mechanisms between the different RBD variants and hACE2 elucidated in this study will provide some insights into the development of drugs targeting the new SARS-CoV-2 variants.

[Inhibition of receptor-interacting protein 3 improves experimental autoimmune hepatitis]

Objective: To evaluate the potential of receptor-interacting protein 3 (RIP3) as a therapeutic target for autoimmune hepatitis (AIH). Methods: Immunofluorescence assay was used to observe the activated expression levels of RIP3 and its downstream signal mixed lineage protein kinase domain-like protein (MLKL) in the liver tissues of patients with AIH and hepatic cyst. Concanavalin A (ConA) was injected into the tail vein to induce acute immune-mediated hepatitis in mice. Intervention was performed by intraperitoneal injection of RIP3 inhibitor GSK872 or solvent carrier. Peripheral blood and liver tissues were collected. Serum transaminases level, qPCR and flow cytometry were analyzed. The intergroup comparison was performed with an independent sample t-test. Results: The expression level of p-RIP3 (the activated forms of RIP3) and phosphorylated p-MLKL (MLKL after phosphorylation) downstream signal were significantly higher in the liver tissue of AIH patients than those of controls. Compared with the control group, the expression levels of RIP3 and MLKL mRNA were significantly increased in the liver tissue of AIH patients (relative expression levels 3.28±0.29 vs. 0.98±0.09, 4.55±0.51 vs. 1.06±0.11), and the differences were statistically significant (t=6.71 and 6.77, respectively, and P<0.01). The expression levels of RIP3 and MLKL mRNA were significantly higher in the mice liver tissue of ConA-induced immune hepatitis than those in the control group (relative expression levels 2.35±0.09 vs. 0.89±0.11,2.77±0.22 vs. 0.73±0.16,t=10.4,6.33, P<0.01). RIP3 inhibitor GSK872 had significantly attenuated ConA-induced immune liver injury and inhibited the expression of tumor necrosis factor-α, interleukin-6, interleukin-1β and NLRP3 in liver. Compared with the control group, the proportions of CD45⁺F4/80⁺ macrophages, CD4⁺ IL-17⁺ Th17 cells, CD4⁺ CD25⁺ regulatory T (Treg) cells and CD11b⁺ Gr-1⁺ myeloid derived suppressor cells (MDSCs) were significantly increased in the liver of ConA + Vehicle group. Compared with ConA + Vehicle group, the proportion of CD45⁺F4/80⁺ macrophages and CD4⁺ IL-17⁺ Th17 cells were significantly decreased, while the proportion of CD4⁺ CD25⁺Treg cells and CD11b⁺ Gr-1⁺ MDSCs with immunomodulatory functions were significantly increased in mice liver of ConA+GSK872 group. Conclusion: AIH patients and ConA-induced immune hepatitis mice have activated RIP3 signal in liver tissues. Inhibition of RIP3 reduces the expression and proportion of proinflammatory factors and cells, and promotes the accumulation of CD4⁺ CD25⁺ Treg cells and CD11b⁺ Gr-1⁺ MDSCs with immunomodulatory functions in the liver of mice with immune hepatitis, thereby alleviating liver inflammation and injury. Therefore, the inhibition of RIP3 is expected to be a new approach for the treatment of AIH.

Computational Design of Miniprotein Inhibitors Targeting SARS-CoV-2 Spike Protein

The ongoing pandemic of COVID-19 caused by SARS-CoV-2 has become a global health problem. There is an urgent need to develop therapeutic drugs, effective therapies, and vaccines to prevent the spread of the virus. The virus first enters the host cell through the interaction between the receptor binding domain (RBD) of spike protein and the peptidase domain (PD) of the angiotensin-converting enzyme 2 (ACE2). Therefore, blocking the binding of RBD and ACE2 is a promising strategy to inhibit the invasion and infection of the virus in the host cell. In the study, we designed several miniprotein inhibitors against SARS-CoV-2 by single/double/triple-point mutant, based on the initial inhibitor LCB3. Molecular dynamics (MD) simulations and trajectory analysis were performed for an in-depth analysis of the structural stability, essential protein motions, and per-residue energy decomposition involved in the interaction of inhibitors with the RBD. The results showed that the inhibitors have adapted the protein RBD in the binding interface, thereby forming stable complexes. These inhibitors display low binding free energy in the MM/PBSA calculations, substantiating their strong interaction with RBD. Moreover, the binding affinity of the best miniprotein inhibitor, H6Y-M7L-L17F mutant, to RBD was ∼45 980 times (ΔG = RT ln Ki) higher than that of the initial inhibitor LCB3. Following H6Y-M7L-L17F mutant, the inhibitors with strong binding activity are successively H6Y-L17F, L17F, H6Y, and F30Y mutants. Our research proves that the miniprotein inhibitors can maintain their secondary structure and have a highly stable blocking (binding) effect on SARS-CoV-2. This study proposes novel miniprotein mutant inhibitors with enhanced binding to spike protein and provides potential guidance for the rational design of new SARS-CoV-2 spike protein inhibitors.

[Efficacy and safety of combination therapy with chemotherapy, programmed death-1 inhibitor and anlotinib in the treatment of advanced dedifferentiated liposarcoma]

Objective: To investigate the efficacy and safety of the combination therapy with chemotherapy, programmed death-1 (PD-1) inhibitor and anlotinib in the treatment of advanced dedifferentiated liposarcoma (DDLPS). Methods: The clinical data of patients with dedifferentiated liposarcoma who received chemotherapy combined with PD-1 inhibitor and anlotinib in the Department of Medical Oncology, Zhongshan Hospital Affiliated to Fudan University from January 1, 2020 to November 30, 2021 were retrospectively analyzed. A total of 24 patients were included in this study, including 12 males and 12 females, with a median age of onset of 56 years (range, 31-69 years). Efficacy and safety in those patients were assessed. Results: All patients had unresectable or metastatic dedifferentiated liposarcoma with G2 (moderate differentiation) or G3 (differential differentiation) in a concise three-grade grading scheme of tumor pathology. Twelve patients received the regimen as the first-line treatment, while the other 7 taken the regimen as second-line treatment and 5 as third-line or above. The median follow-up time for overall survival (OS) was 7.7 months. The overall response rate (ORR) was 20.8% (5/24) and disease control rate (DCR) was 83.3% (20/24) with 5 partial response (PR), 15 stable disease (SD) and 4 progressive disease (PD). Overall, the median progression-free survival (PFS) was 4.9 months (95%CI: 3.4-16.2 months). The ORR of anthracycline-based, eribulin-based or gemcitabine-based regimens was 1/12, 2/6 and 2/6, respectively; and the median PFS was 7.7, 7.3 and 4.4 months, respectively. Waterfall plots showed notable tumor shrinkage of any degree in eribulin and gemcitabine-based regimens(3/6 and 2/6, respectively), while there were more patients presented with SD in anthracycline-based group(9/12). Common adverse reactions included myelosuppression, fatigue, anorexia, rash, pruritus, palpitate, hypothyroidism and hypertension. Conclusions: The combination regimen with chemotherapy, PD-1 inhibitor and anlotinib in the treatment of advanced DDLPS is effective and well tolerable. There are more responders in eribulin or gemcitabine-based regimens.

[Analysis of the effectiveness of coracoid osteotomy and concentric coaxial reconstruction of the glenoid cavity in the treatment of recurrent anterior dislocation of the shoulder joint]

Objective: To investigate the clinical efficacy of the modified Latarjet procedure in the treatment of recurrent anterior subluxation of the shoulder by "coaxial co-arc" reconstruction of the glenoid cavity. Methods: The clinical data of 103 cases (106 shoulders) of recurrent anterior dislocation of the shoulder admitted to the First Affiliated Hospital of the Army Military Medical University from January 2005 to December 2020 were retrospectively studied. Out of these cases, 84 were males and 19 were females; 31 with left-sided injuries while 75 with right-sided injuries, with a mean age of (29.4±11.5) years (16-61 years). The preoperative anterior fear test was positive, and a modified Latarjet procedure was used to reconstruct the shoulder glenoid defect through a "coaxial co-arc". The Rowe score, simple shoulder test (SST) score, and Visual analogue scale (VAS) score of pain were used to assess the shoulder's function. Parameters such as the postoperative shoulder recurrent dislocation rate, shoulder body external rotation angle, and subscapularis muscle strength changes were recorded postoperatively. Moreover, radiographs and CT scans were used to check for the incidence of osteoarthritis (Samson-Prieto score). Results: After a mean follow-up of 9.0 years (1 to 16 years), bony healing occurred 3 to 6 months postoperatively. The Rowe score improved from 40.4±6.5 preoperatively to 93.2±2.5 (P<0.001), the SST score improved from 5.2±1.3 preoperatively to 10.1±1.5 (P<0.001), and the VAS pain score decreased from 3.5±1.9 preoperatively to 1.1±1.2 (P<0.001) at the final follow-up. The angle of lateral external rotation of the shoulder joint was 58.8°±15.6° preoperatively and 57.6°±14.5° postoperatively with no statistically significant difference (P>0.05). There was no statistically significant difference in the measurement of subscapularis muscle strength between the healthy side and the affected side (P>0.05). In 89.6% of patients after surgery, coaxial co-arc reconstruction of the shoulder glenoid was obtained, and the shoulder glenoid defect and postoperative inclusion angle were significantly improved compared with those before surgery (P<0.001). Postoperatively, new-onset osteoarthritis developed in 7 cases (7/98), arthritis progressed in 2 cases (2/8), incisional healing was poor in 2 cases (2/98), and revision surgery was performed in 2 cases (2/98) due to bone mass detachment. Conclusion: Coracoid osteotomy and concentric coaxial reconstruction of the glenoid cavity elicits adequate good clinical efficacy for cases of recurrent anterior shoulder dislocation, with low recurrence rates, low revision rates and low incidence of osteoarthritis.

Refine the evaluation of photophysical properties of organometallic chromophores under confined molecular crystal conditions

Many impressive results have been achieved in the researches and developments of luminescent chromophore materials by combining experimental synthesis and characterization with the cooperative theoretical calculation. However, the existing theoretical studies are usually based on the intrinsic properties of isolated molecules and extend their properties to the whole molecular material directly, which will lead to the persistence of errors and affect the computational design of molecular materials with different morphology. Therefore, the study of multimolecular systems needs to further consider the environmental effects on molecules. This work is based on the calculation of a series of crystalline Ir(III) complexes under background charge conditions to reveal how the surrounding charge affects the photophysical properties of a series of transition metal Ir(III) complex materials. Through this method, the study of crystalline complexes is found to be more authentically reproduced the charge transfer state, energy level, and reorganization energy, etc., and shows the changes of luminescence characteristics and efficiency. The change of the electronic structure of the target molecule would be characterized more comprehensively, thus obtaining more accurate results for the excited states properties of molecular materials.

Molecular Dynamics Simulation Investigation of the Binding and Interaction of the EphA6-Odin Protein Complex

Protein-protein interaction plays an important role in the development of almost all cells. Elucidating the dynamic binding and affinity of a protein-protein complex is essential for understanding the biological functions of proteins. EphA6 and Odin proteins are members of the Eph (erythropoietin-producing hepatocyte) receptor family and the Anks (ankyrin repeat and sterile α motif domain-containing) family, respectively. Odin significantly functions in regulating endocytosis, degradation, and stability of EphA receptors. In this work, the key residues of the interaction interface were determined through a hydrogen bond, root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), and dynamic correlation analysis of the conventional molecular dynamics (MD) simulations. The calculated standard binding free energy, -7.92 kcal/mol, between EphA6 and Odin is quite consistent with the experimental measurement value, -8.73 kcal/mol. By the combination of several MD simulation techniques, our investigation of the binding process reveals the detailed representative characteristics of the entire binding pathway at the molecular level. Based on the obtained potential of the mean force (PMF) curve, the analysis of the simulation trajectories shows that the residue Arg1013 in the receptor EphA6 is responsible for capturing Asp739 and Asp740 in the ligand Odin during the initial stage of binding. In the later stage of binding, the hydrogen bonds and salt bridges between a series of residues Lys973, Leu1007, Gly1009, His1010, and Arg1012 in the receptor and residues Leu735, Asn736, Asp739, Asp740, and Asp753 in the ligand mainly contribute to the stability of the protein complex. In addition, the specific change process of the receptor-ligand-binding mode is also clarified during the binding process. Our present simulation will promote a deep understanding of the protein-protein interaction, and the identified key interresidue interaction will be theoretical guidance for the design of protein drugs.

[Analysis and management of delayed cerebrospinal fluid rhinorrhea after invasive pituitary adenoma surgery]

Objective: To investigate the related factors and treatments of delayed cerebrospinal fluid rhinorrhea (CFR) after invasive pituitary adenoma (IPA) surgery. Methods: One hundred and forty-two patients with IPA treated in Tianjin Huanhu Hospital from January 2014 to January 2019 were analyzed retrospectively, including 62 males and 80 females, aging from 38 to 67 years. The clinical data of patients before and after operation were collected. All patients with postoperative CFR underwent endoscopic CFR repair. During the operation, residual or recurrent pituitary adenomas were resected, the dura around the leak was enlarged and the necrotic tissue was removed. For those who still had fluid leakage after repair, the necrotic tissue was cleaned up, the leakage was filled and reinforced under endoscopy. Endoscopic rhinorrhea repair was performed if necessary. The cerebrospinal fluid leak was repaired with multi-layer materials. The related risk factors of delayed CFR after operation were analyzed. SPSS 19.0 software was used for statistical analysis. Results: Among the 142 patients in this group, 64 cases underwent total tumor resection and 78 cases underwent non-total tumor resection. They were followed up for 6 to 72 months. Thirty-one cases had delayed CFR, with an incidence of 21.83%, and occurred between 1 and 5 years postoperatively, with an average of 2.4 years. All 31 patients with delayed CFR underwent endoscopic CFR repair. The nasal endoscopy was rechecked at 2 weeks, 1 month, 3 months and 6 months after operation. Twenty-eight patients were repaired successfully after 1 operation, while 2 patients after 2 operations and 1 patient after 3 operations. These patients were followed up for 6 to 60 months, and no CFR occurred again. Univariate analysis showed that the degree of tumor resection, recurrence, size, texture, postoperative radiotherapy and operator experience were the risk factors of delayed CFR (all P<0.05). Multivariate analysis showed that the degree of tumor resection and recurrence were the highest independent risk factors for postoperative CFR, and tumor size, texture, postoperative radiotherapy and operator experience were the independent risk factors in this study. Conclusions: Delayed CFR after IPA is related to the degree of tumor resection, recurrence, size, texture, postoperative radiotherapy and the operator experience. It is necessary to completely remove the tumor under endoscope, to expand resection of the dura and necrotic tissue around the leak, to repair the defect with multi-layer materials, to follow-up closely and to repair timely after operation.

Altered task modulation of global signal topography in the default-mode network of unmedicated major depressive disorder

BACKGROUND

Altered global signal (GS) topography features in the resting-state fMRI of major depressive disorder (MDD), showing abnormally strong global signal representation in the default-mode network (DMN). Whether the abnormal local to global change also shapes activity during task states, and how it relates to psychopathological symptoms, e.g., abnormally slow time speed of motor, cognitive, and affective symptoms, remains unknown.

METHODS

We investigated fMRI-based GS with its topographical representation during task states in unmedicated 51 MDD subjects and 28 healthy subjects. Task-related global signal correlation (GSCORR) was probed by a novel paradigm testing the processing of negative/neutral emotions during different time speeds, i.e., slow and fast.

RESULTS

We observed a significant interaction between time speed and emotion of GSCORR in various DMN regions in healthy subjects. Next, we showed that MDD exhibits reduced task-related GSCORR in various DMN regions during specifically the fast processing of negative emotions. Finally, we demonstrated that GSCORR in DMN and other brain regions (motor-related regions, inferior frontal cortex) correlated with the degree of psychomotor retardation especially during the fast emotional stimuli.

LIMITATIONS

The measurement of interoceptive variables like respiration rate or heart rate were not included in our fMRI acquisition.

CONCLUSION

Together, we demonstrated the functional relevance of GS topography by showing reduced GSCORR in DMN during specifically the fast processing of negative emotions in MDD, suggesting the abnormal slowness, i.e., reduced time speed, to be a key feature of both brain and symptoms in MDD.

A theoretical study based on DFT calculations on the different influence of functional groups on the C–H activation process via Pd-catalysed β-X elimination

We have performed a series of theoretical calculations for palladium-catalyzed β-X elimination reactions. The DFT calculation combined with energy decomposition analysis shows the determining factors of reactivity. Such as, the elemental composition, the structure of different functional groups and the stronger steric repulsions contribution.

The energy decomposition analysis (EDA) results show the quantitative contribution of nucleophile groups in intramolecular interactions.

Investigation of the adsorption properties of gemcitabine anticancer drug with metal-doped boron nitride fullerenes as a drug-delivery carrier: a DFT study

Anticancer-drug delivery is now becoming a challenging approach for researchers as it allows controlled drug delivery near cancerous cells with minimized generic collection and the avoidance of secondary side effects. Hence in this work, the applications of nanostructures as anticancer drug-delivery carriers were widely investigated to target cancerous tissues. Based on DFT calculations, we investigated the transition metal-doped boron nitride nanostructure as a drug-delivery agent for the gemcitabine drug utilizing the B3LYP/6-31G (d, p) level of theory. In this research, the adsorption energy and electronic parameters of gemcitabine on the interaction with the metal-doped BN nanostructures were studied. It has been observed that metal doping significantly enhances the drug-delivery properties of BN nanostructures. Among the investigated nanostructures, Ni–BN has been found to be the most prominent nanostructure to transport gemcitabine with an elevated value of adsorption energy in both the gas phase (−45.79) and water media (−32.46). The interaction between gemcitabine and BN nanostructures was confirmed through frontier molecular orbitals and stabilization energy analysis. The fractional charge transfer, MEP, NCI, and NBO analyses exposed the charge transfer from drug molecule to the BN nanostructures. Transition density maps and UV-VIS spectra were also plotted to investigate the excited-state properties of the designed complexes. Thus, the present study provides an in-depth interaction mechanism of the gemcitabine drug with BN, which reveals that metal-doped BN nanostructures can be a favorable drug-delivery vehicle for the gemcitabine anticancer drug.

Anticancer-drug delivery is now becoming a challenging approach for researchers as it allows controlled drug delivery near cancerous cells with minimized generic collection and the avoidance of secondary side effects.

Predicting a Kind of Unusual Multiple-States Dimerization-Modes Transformation in Protein PD-L1 System by Computational Investigation and a Generalized Rate Theory

The new cancer immunotherapy has been carried out with an almost messianic zeal, but its molecular basis remains unclear due to the complexity of programmed death ligand 1 (PD-L1) dimerization. In this study, a new and integral multiple dimerization-modes transformation process of PD-L1s (with a new PD-L1 dimerization mode and a new transformation path discovered) and the corresponding mechanism are predicted using theoretical and computational methods. The results of the state analysis show that 5 stable binding states exist in system. A generalized inter-state transformation rate (GITR) theory is also proposed in such multiple-states self-assembly system to explore the kinetic characteristics of inter-state transformation. A “drug insertion” path was identified as the dominant path of the PD-L1 dimerization-modes transformation. Above results can provide supports for both the relative drug design and other multiple-states self-assembly system from the theoretical chemistry perspective.

C2-C3 Anterior Cervical Diskectomy and Fusion for Hangman's Fractures with C2 Posterior Dislocation: Technical Notes

BACKGROUND

The overwhelming majority of hangman's fractures cause anterior dislocation of C2. Hangman's fracture with C2 posterior dislocation is extremely rare; only 1 pediatric case was reported in 2018 to date. This kind of injury cannot be cataloged using current classification schemes, and no established treatment recommendations exist. The purpose of this article is to report a rare case of a hangman's fracture with C2 posterior dislocation, which does not fit into existing classification systems and discuss management technical notes to avoid pitfalls.

METHODS

We describe this case, review relevant literature, and share our experience.

RESULTS

A 31-year-old male sustained a hangman's fracture with C2 posterior dislocation after he fell into a 50-cm deep roadside ditch when riding a motorcycle. Radiograph and computed tomography on admission showed fractures through both pars of C2 and C2 posterior dislocation. Magnetic resonance imaging on admission showed high T2-weighted signal intensity of cervical spinal cord and compression of the cervical spinal cord by posterior dislocation of the C2 vertebral body. A C2-3 anterior cervical diskectomy and fusion was performed. At 6 months after operation, bony fusion was achieved and magnetic resonance imaging showed the T2-weighted signal hyperintensity of cervical spinal cord before surgery disappeared.

CONCLUSIONS

C2-C3 anterior cervical diskectomy and fusion is recommended for hangman's fractures with C2 posterior dislocation. Traction before surgery is not recommended.

Accurate Analysis of Anisotropic Carrier Mobility and Structure-property Relationships in Organic BOXD Crystalline Materials

Charge mobility is an essential factor of organic crystalline materials. Although many investigators have made important progress, the exact relationship between the crystal structure and carrier mobility remains to be clarified. Fortunately, a series of bis-1,3,4-oxadiazole derivatives have been successfully prepared and reported. They have similar main molecular fragments but different crystal packing modes, which provide an ideal research objective for studying the effect of molecular packing on charge mobility in organic photoelectric conversion systems. In this work, the charge mobilities of these molecules are systematically evaluated from the perspective of first-principles calculation, and the effect of a molecular overlap on orbital overlap integral and final charge carrier mobility is fully discussed. It can be seen that the small intermolecular distance (less than 6 Å) is the decisive factor to achieve high electron mobility in π stacking, and better mobility can be obtained by increasing the hole migration distance appropriately. A larger dihedral angle of anisotropy is an important point limiting the charge mobility in the herringbone arrangement. It is hoped that the correlation results between the crystal structure and mobility can assist the experimental study and provide an effective way to improve the photoelectric conversion efficiency of the organic semiconductor devices and multiple basis for multiscale material system characterization and material information.

Computational insight into newly anomalous delayed fluorescence emitters based on D-A-A structures

In variety of skeleton structures of delayed fluorescence molecular materials, the D-A-A type has been widely concerned recently for its improved double efficiency of reverse intersystem crossing process (RISC). Based on the D-A-A structure, eight new D-TRZ-nPO molecules (D = dihydrophenazine (DHPZ), phenothiazine (PTZ), phenoxazine (PXZ) and 9,9-dimethyl-9,10-dihydroacridan (DMAC), TRZ = triphenyltriazine, n = 1 or 2) with potential performance improvement have been deeply investigated by theoretical calculations. Interestingly, these molecules with the closing energy levels of high-lying excited states and charge transfer characters may perform rare high-lying excited state delayed fluorescence. Meanwhile, the changes of RISC and the corresponding effects caused by D-A-A structure from low energy level to high energy level are analyzed in detail. Furthermore, DHPZ-TRZ-2PO with blue emission (452 nm) is expected to be a potential high-lying excited state delayed fluorescence material candidate.

[Clinicopathological characteristics and prognosis of young patients with upper tract urethelial carcinoma]

Objective: To investigate the clinicopathological characteristics and prognosis of the young patients with upper tract urothelial carcinoma (UTUC). Methods: The clinical data of 839 UTUC patients receiving radical nephroureterectomy at Peking University Third Hospital, Beijing, China from September 1999 to September 2019 were retrospectively analyzed. The patients were divided into the young (<55 years old, 107 cases) and elderly groups (≥55 years old, 732 cases). After the variables were balanced using propensity score matching, the patients were paired at a 1∶1 ratio. The clinicopathological characteristics and survival rates were compared between the two groups. Results: Compared with the elderly group, the young group had more males (P=0.047), a higher rate of smoking history (P=0.042), a higher rate of renal transplantation history (P<0.01), and fewer symptoms of hematuria (P=0.048). The 1-, 3-, and 5-year cancer specific survival (CSS) rates after surgery were 77.9%, 62.2%, 60.2% and 85.7%, 70.3%, 65.0% in the young and the elderly groups, respectively. The CSS and disease free survival (DFS) of young patients were shorter than those of elderly patients, but the difference was not significant either by subgroup analysis or propensity matching analysis (P>0.05). Young female patients had shorter CSS (P=0.034) and DFS (P=0.046) than elderly females. Perineural invasion (CSS, P=0.002; DFS, P<0.01) and extensive necrosis (CSS, P=0.041; DFS, P=0.001) were the independent risk factors of survival in young patients. Conclusions: Young UTUC patients are different from elderly ones in the frequencies of gender, smoking history, renal transplantation history, and first symptoms. Young female patients have a worse prognosis than elderly female ones. Perineural invasion and extensive necrosis could help clinicians to evaluate the prognosis of young UTUC patients.

Computational Studies on the Materials Combining Graphene Quantum Dots and Pt Complexes with Adjustable Luminescence Characteristics

Graphene materials with particular properties are proved to be beneficial to photoelectric devices, but there are rare reports on a positive effect by graphene on emissive layer materials of organic light-emitting diodes (OLEDs) previously. On the basis of the latest important experiments, an OLED device with the aid of graphene quantum dots shows the dawn of their application for luminescent materials. The luminescence performance has been improved, but the understanding of the internal excited-state radiation mechanism of the material needs further study. In this work, the Pt(II)-coordinated graphene quantum dot coplanar structures with different shapes are studied theoretically in detail, and the results present the improvement in phosphorescence under the promoted radiative decay and suppressed nonradiative decay. This composite combines the advantages of transition metal complexes and graphene quantum dots and also exhibits excellent properties in the light absorption region and carrier transportation for the OLED. This comprehensive theoretical calculation research can provide a comprehensive basis of the material design in the future.

[Analysis of pregnancy outcomes of D6 single blastocyst transplantation in fresh and frozen-thawed cycles]

Objective: To compare the main clinical outcomes of Day 6 (D6) single blastocyst transplantation in fresh and frozen-thawed cycles. Methods: The data of fresh blastocyst transplantation patients and frozen-thawed blastocyst transplantation patients from January 2013 to December 2017 were retrospectively analysed. Fresh blastocyst transplantation and frozen-thawed blastocyst transplantation were matched in a ratio of 1∶3 by using propensity score matching, the matching factors included age, body mass index, thickness of endometrium and blastocyst grade. Totally 180 cases were included in the fresh cycle group and 540 cases in the frozen-thawed cycle group. Results: There was no significant difference in basal FSH between the two groups [(6.9±2.5) versus (6.4±3.8) U/L, P=0.334]. The positive rate of hCG in D6 blastocyst fresh cycle transplantation group [32.8%(59/180) versus 48.1%(260/540)], clinical pregnancy rate [28.9%(52/180) versus 43.5%(235/540)] and live birth rate [21.1%(38/180) versus 32.2%(174/540)] were lower than those of frozen-thawed cycle group (all P<0.05). The miscarriage rate was higher [26.9%(14/52) versus 24.7%(58/235)], but there was no statistical difference (P>0.05). Conclusions: The clinical pregnancy outcome of D6 single blastocyst frozen-thawed cycle transplantation is better than that of fresh cycle. In order to obtain better clinical outcomes, frozen-thawed cycle transplantation of blastocysts formed on the 6th day is recommended.

Interaction Mechanism of the Germination Stimulants Karrikins and Their Receptor ShKAI2iB

The significance of karrikins (KARs) in plant physiology opens a door for their application in the agricultural production. As the first event of the whole signaling pathway, the binding of smoke-derived signal molecules KARs to the receptor protein KAI2 triggers the germination of the primary dormant seeds of all angiosperms, not just the "fire-prone" taxa. In the present study, all-atom molecular dynamics simulations, along with the accurate estimation of the ligand-receptor binding free energy, were used to investigate the atomic level interaction of all the members of the KARs family (from KAR₁ to KAR₆) with the receptor ShKAI2iB, an intermediate-evolving KAI2 from Striga hermonthica. The calculated binding energy value of KAR₁ to ShKAI2iB, -5.64 kcal/mol, is in good agreement with the available experimental data, -5.67 kcal/mol. The further analysis of the detailed interaction between each KAR and the protein reveals the primary reasons for the difference of the affinity of the diverse ligands with the receptor and displays the regional characteristics of the protein's active site. Our research will not only provide clues for the study of equivalent endogenous phytohormone, but also contribute to the development of synthetic germinating chemicals.

[Long-term Stability of Aerobic Granular Sludge Under Low Carbon to Nitrogen Ratio]

Long-term stability is important for the practical application of aerobic granular sludge system under low carbon to nitrogen ratio (C/N). In this study, aerobic granular sludge, seeded in the reactors A and B, were cultivated under low C/N to investigate the properties, performance, and resilience to shock load in the long-term operation. The load of carbon and nitrogen in the feed was increased gradually. The C/N of reactor A was kept at 2, while that of reactor B was kept at 4 initially and then reduced to 2 in the shock load stage. It was discovered that the aerobic granular sludge stored at 4℃ for 30 days was essentially revived after 25 days of cultivation in reactors A and B, with over 90% removal efficiency for COD and ammonia, respectively. In the following stages, the removal efficiencies of COD and ammonia in reactor B were over 90% and complete nitrification was achieved. In contrast, in reactor A, the removal efficiency of COD was only 80% and only partial nitrification was achieved; however, ammonia removal efficiency of 90% was finally achieved. In the shock load stage, the COD removal efficiencies in reactors A and B were still above 80%, but the ammonia removal efficiencies were severely affected. The removal of ammonia was deteriorated in reactor A, while only partial nitrification was achieved in reactor B. During the entire operation, the physical properties of the aerobic granules in reactors A and B were barely affected, with sludge volume index (SVI₃₀) in reactors A and B maintained at 60 mL ·g^-1 and 75 mL ·g^-1, and mixed liquid suspended solid (MLSS) at 5 g ·L^-1and 3.7 g ·L^-1, respectively. Microbial analysis showed that the aerobic granular sludge in reactor B has richer and more diverse microbial community than that in reactor A. The abundance of Zoogloea in reactor B, which is simultaneously able to produce polymeric protein and stabilize the structure of the aerobic granules, may be favorable for the high stability of the aerobic granules. These findings suggested that the aerobic granular system under the C/N of 4 had better performance in ammonia removal and higher tolerance to shock load, which guaranteed high stability of the aerobic granular sludge system in long-term operation, as compared to that under the C/N of 2.

Molecular-Level Insight of Cu(I) Complexes with the 7,8-Bis(diphenylphosphino)-7,8-dicarba-nido-undecaborate Ligand as a Thermally Activated Delayed Fluorescence Emitter: Luminescent Mechanism and Design Strategy

Investigation of the clear structure-property relationship and microscopic mechanism of thermally activated delayed fluorescence (TADF) emitters with high emission quantum yield is a direction worthy of continuous efforts. The instructive theoretical principle of TADF material design is critical and challenging. Here, we carried out theoretical calculation on two experimental Cu(I) complexes with the same 7,8-bis(diphenylphosphino)-7,8-dicarba-nido-undecaborate (dppnc) but different N^N ligands [dmbpy = 6,6'-dimethyl-2,2'-bipyridine (1) or dmp = 2,9-dimethyl-1,10-phenanthroline (2)] to briefly elaborate the structure-TADF performance relationship and luminescence mechanism. It was found that enhanced rigidity by the fused benzene ring between two pyridyl units in complex 2 leads to (i) higher allowedness of S₁ → S₀, (ii) more effective reverse intersystem crossing (RISC), and (iii) better relative stability of the T₁ state, which could be responsible for its excellent TADF behavior. Thus, a strategy of extending π conjugation in the N^N ligand could be deduced to further enhance the quantum yield. We validated it and have succeeded in designing analogue complex 4 by extending π conjugation with an electron-withdrawing pyrazinyl. Benefiting from the smaller energy gap (ΔE_ST) and plunged reorganization energy between the S₁ and T₁ states, the rate of RISC in complex 4 (1.05 × 10⁸ s^-1) increased 2 orders of magnitude relative to that of 2 (5.80 × 10⁶ s^-1), showing more superiority of the TADF behavior through a better balance of RISC, fluorescence, and phosphorescence decay. Meanwhile, the thermally activated temperature of 4 is only 165 K, implying that there is a low-energy barrier. All of these indicate that the designed complex 4 may be a potential TADF candidate.

[Therapeutic effect of tonsillectomy on IgA nephropathy after kidney transplantation]

Objective: To observe the clinical effect of tonsillectomy on IgA nephropathy (IgAN) after renal transplantation. Methods: From March 2011 to July 2018, 201 kidney transplantation recipients who were diagnosed of IgAN by transplant renal biopsy in the Department of Organ Transplantation of the First Affiliated Hospital of Sun Yat-sen University were retrospectively reviewed, of which 18 patients underwent tonsillectomy after renal biopsy. The clinical data of the 18 patients were collected, patient and kidney survival time and function of the transplanted kidney were analyzed. Results: Of the 18 recipients, 13 were male and 5 were female, with an average age of (36.0±10.9) years. All 18 patients survived during follow-up. Two patients returned to dialysis treatment 10 months and 14 months after tonsillectomy, respectively. The creatinine was 94 (78, 133) μmol/L, 95 (74, 139) μmol/L, 106 (87, 158) μmol/L and 95(81, 147) μmol/L before tonsillectomy, 3 months, 1 year and 2 years after tonsillectomy, respectively (P=0.206). Urinary protein quantification was 0.31 (0.16, 1.38) g/24 h, 0.34 (0.10, 1.42) g/24 h, 0.33 (0.11, 0.56) g/24 h and 0.25 (0.10, 0.50) g/24 h at the same time points, respectively (P=0.104). The two patients who returned to dialysis were diagnosed of IgAN by transplant renal biopsy because of elevated creatinine, proteinuria and hematuria, 9 years and 4 years after kidney transplant respectively. Renal biopsy suggested that glomerular and segmental sclerosis were 7/24, 5/24 and 1/6, 2/6, respectively. Additionally, interstitial fibrosis and tubular atrophy (IF/TA) were both occupied 30% in the biopsies, and tonsillectomy was performed 461 days and 1 077 days after diagnosis of IgAN, respectively. Conclusions: Tonsillectomy can maintain the stability of renal function and prevent the aggravation of proteinuria in IgAN patients after renal transplantation. However, if pathology suggests obvious glomerulosclerosis or IF/TA, tonsillectomy may not be effective.

Lighting Silver(I) Complexes for Solution-Processed Organic Light-Emitting Diodes and Biological Applications via Thermally Activated Delayed Fluorescence

Luminescent coinage metal complexes have shown promising applications as electroluminescent emitters, photocatalysts/photosensitizers, and bioimaging/theranostic agents, rendering them attractive alternatives to transition metal complexes based on iridium, ruthenium, and platinum that have extremely low earth abundance. In comparison to the widely studied Au(I) and Cu(I) complexes, Ag(I) complexes have seldom been explored in this field because of their inferior emission properties. Herein, we report a novel series of [Ag(N^N)(P^P)]PF₆ complexes exhibiting highly efficient thermally activated delayed fluorescence by using easily accessible neutral diamine ligands and commercially available ancillary diphosphine chelates. The photoluminescence quantum yields (PLQYs) of the Ag(I) emitters are ≤0.62 in doped films. The high PLQY with a large delayed fluorescence ratio enabled the fabrication of solution-processed organic light-emitting diodes (OLEDs) with a high maximum external quantum efficiency of 8.76%, among the highest values for Ag(I) emitter-based OLEDs. With superior emission properties and an excited state lifetime in the microsecond regime, together with its potent cytotoxicity, the selected Ag(I) complex has been used for simultaneous cell imaging and anticancer treatment in human liver carcinoma HepG2 cells, revealing the potential of luminescent Ag(I) complexes for biological applications such as theranostics.

In Silico Study of Membrane Lipid Composition Regulating Conformation and Hydration of Influenza Virus B M2 Channel

The proton conduction of transmembrane influenza virus B M2 (BM2) proton channel is possibly mediated by the membrane environment, but the detailed molecular mechanism is challenging to determine. In this work, how membrane lipid composition regulates the conformation and hydration of BM2 channel is elucidated in silico. The appearance of several important hydrogen-bond networks has been discovered, as the addition of negatively charged lipid palmitoyloleoyl phosphatidylglycerol (POPG) and cholesterol reduces membrane fluidity and augments membrane rigidity. A more rigid membrane environment is beneficial to expand the channel, allow more water to enter the channel, promote channel hydration, and then even affect the proton conduction facilitated by the hydrated channel. Thus, membrane environment could be identified as an important influence factor of conformation and hydration of BM2. These findings can provide a unique perspective for understanding the mechanism of membrane lipid composition regulating conformation and hydration of BM2 and have important significance to the further study of anti-influenza virus B drugs.

[Interrupted time series analysis for influence on HIV related fatality of implementation of 'Four Free Services One Care' policy in China]

Objective: To analyze influence on HIV related fatality of implementation of 'Four Free Services One Care' policy in China during 1993-2012, and evaluate effectiveness for the policy of HIV/AIDS prevention and treatment. Methods: The data during 1993-2003 (before the implementation of the policy) and during 2005-2012 (after the implementation of the policy) were collected from the national HIV/AIDS Comprehensive Response Information Management System for the analysis on HIV related fatality in Chinese, especially in rural residents. Interrupted time series analysis was used to analyze the trends of HIV related fatality during 1993 and 2012. Results: During the twenty years from 1993 to 2012, the HIV related fatality in China decreased, and the HIV related fatality in rural areas was higher than the overall HIV related fatality. Compared with the period before the implementation of the policy, the overall HIV related fatality decreased by 1.5% (P=0.156) and the HIV related fatality in rural residents decreased by 2.6% in 2004 when the policy was implemented (P=0.094). As for the change of slope, the overall slope rate after the policy implementation was -0.466 (P=0.005), indicating a decrease trend of HIV related fatality. The slope rate after the policy implementation in rural residents was-0.592 (P=0.005), indicating a decrease trend of HIV related fatality. At the same time, the slope rate after the policy implementation in rural residents infected through blood transmission route was-0.766 (P<0.001), indicating a decrease trend of HIV related fatality. Conclusions: The implementation of the 'Four Free Services One Care' policy in China has made remarkable progress in free HIV antiviral therapy.

How does the porphyrin-like vacancy affect the spectral properties of graphene quantum dots? A theoretical study

By processing graphene quantum dot, an ideal semiconductor material with suitable band gap and higher electron mobility can be obtained. Thus, it has a broad prospect in the application of photoelectric response materials. Here, a graphene defect with porphyrin-like structure is selected to achieve the controlable light absorption. The double five-membered-ring parallel vacancy are based on self-healing properties of popular graphene defects. Aimed to separate exciton and hole more effectively and achieve higher photoelectric conversion efficiency, the occupied orbital and unoccupied orbital of the quantum dot with objected defect structure is taken as orderly dispersion to form an obvious charge separation state under the demonstration with first principles calculation. Most importantly, a real time real space charge separation is calculated by time-dependent ab-initio quantum dynamics based on numerical atomic basis sets. The result shows the specific graphene defects can form an efficient pure graphene photoelectric response medium like porphyrin skeleton, and the vacancy will induce to adjust and control the specific wavelength of the response light and charge separated state manipulably with odevity of number of peripheral carbon rings by the calculation of ultrafast process.

[Association of dietary patterns and diabetes risk level among adult residents in Datong city of Shanxi Province]

Objective: To explore the association of dietary pattern and type 2 diabetes mellitus (T2DM) risk. Methods: In 2013, 3 747 participants from 87 coalmine branches of a large coal mine group in Datong City, Shanxi Province were selected by using a two-stage cluster stratified sampling method. Data on demographic characteristics, smoking, drinking, and family history of diabetes were collected by using a self-made questionnaire, and the International Physical Activity Questionnaire was used to assess the level of physical activity. Physical, glucose and lipid metabolism indicators were measured and subjects were divided into high-risk groups and low-risk groups of T2DM according to the T2DM risk score. Dietary data were collected by using Semi-quantitative Food Frequency Questionnaire, and dietary patterns were derived by using the exploratory factor analysis and cluster analysis. The unconditional logistic regression model was used to assess the association of dietary patterns and T2DM risk. Results: The age of the subjects was(41.48±8.62) years old, and 2 843 of them were males (84.31%). A total of 1 819 subjects were in the high-risk group and 1 553 in the low-risk group. Four dietary patterns, healthy diet, high-salt diet, meats diet, and carbohydrate-rich diet, were identified in this study. The unconditional logistic regression analysis showed that compared with the healthy diet pattern, after the adjustment of demographic characteristics, smoking, and drinking, the OR (95%CI) of T2DM risk in high-salt diet, carbohydrate-rich diet and meats diet patterns was 1.54 (1.26-1.88), 1.80 (1.43-2.28) and 1.20 (0.99-1.46), respectively. Conclusion: High-salt diet and carbohydrate-rich diet were positively associated with T2DM risk, whereas there was no association of meats diet and T2DM risk.

A novel T-C3N and seawater desalination

A structurally stable stacked multilayer carbonitride is predicted with the aid of ab initio calculations. This carbonitride consists of C3N tetrahedra, and is similar to T-carbon and thus named T-C3N. Its 2-dimensional (2D) monolayer is also carefully investigated in this work. The studies on electronic properties reveal that bulk and 2D T-C3N are insulators with a 5.542 eV indirect band gap and a 5.741 eV direct band gap, respectively. However, the monolayer T-C3N exhibits an excellent uniform porosity. Its 5.50 Å pore size is perfect for water nanofiltration. The adsorption and permeation of water molecules on the monolayer T-C3N are investigated. Its promising potential application in highly efficient nanofiltration membranes for seawater desalination is discussed.