Quasifree Neutron Knockout Reaction Reveals a Small s-Orbital Component in the Borromean Nucleus ^{17}B

A kinematically complete quasifree (p,pn) experiment in inverse kinematics was performed to study the structure of the Borromean nucleus ^{17}B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for 1s_{1/2} and 0d_{5/2} orbitals, and a surprisingly small percentage of 9(2)% was determined for 1s_{1/2}. Our finding of such a small 1s_{1/2} component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in ^{17}B. The present work gives the smallest s- or p-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of s or p orbitals is not a prerequisite for the occurrence of a neutron halo.

Strong Superexchange in a d^{9-δ} Nickelate Revealed by Resonant Inelastic X-Ray Scattering

The discovery of superconductivity in a d^{9-δ} nickelate has inspired disparate theoretical perspectives regarding the essential physics of this class of materials. A key issue is the magnitude of the magnetic superexchange, which relates to whether cuprate-like high-temperature nickelate superconductivity could be realized. We address this question using Ni L-edge and O K-edge spectroscopy of the reduced d^{9-1/3} trilayer nickelates R_{4}Ni_{3}O_{8} (where R=La, Pr) and associated theoretical modeling. A magnon energy scale of ∼80  meV resulting from a nearest-neighbor magnetic exchange of J=69(4)  meV is observed, proving that d^{9-δ} nickelates can host a large superexchange. This value, along with that of the Ni-O hybridization estimated from our O K-edge data, implies that trilayer nickelates represent an intermediate case between the infinite-layer nickelates and the cuprates. Layered nickelates thus provide a route to testing the relevance of superexchange to nickelate superconductivity.

Properties of Heavy Secondary Fluorine Cosmic Rays: Results from the Alpha Magnetic Spectrometer

Precise knowledge of the charge and rigidity dependence of the secondary cosmic ray fluxes and the secondary-to-primary flux ratios is essential in the understanding of cosmic ray propagation. We report the properties of heavy secondary cosmic ray fluorine F in the rigidity R range 2.15 GV to 2.9 TV based on 0.29 million events collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The fluorine spectrum deviates from a single power law above 200 GV. The heavier secondary-to-primary F/Si flux ratio rigidity dependence is distinctly different from the lighter B/O (or B/C) rigidity dependence. In particular, above 10 GV, the F/Si/B/O ratio can be described by a power law R^{δ} with δ=0.052±0.007. This shows that the propagation properties of heavy cosmic rays, from F to Si, are different from those of light cosmic rays, from He to O, and that the secondary cosmic rays have two classes.

The interplay between spatial and heliconical orientational order in twist-bend nematic materials

The helical pitch formed by organic molecules, such as the α-helix of proteins, usually requires hydrogen bonding between chiral units and long-range positional order. It was recently found that certain liquid crystal oligomers can have a twist-bend nematic (NTB) phase with nanoscale heliconical structure without hydrogen bonding, molecular chirality or positional order. To understand the nature of this unique structure, here we present hard and resonant tender X-ray scattering studies of two novel sulfur containing dimer materials. We simultaneously measure the temperature dependences of the helical pitch and the correlation length of both the helical and positional order. In addition to an unexpected strong variation of the pitch with the length of the spacer connecting the monomer units, we find that at the transition to the NTB phase the positional correlation length drops. The helical structure was found not only in the NTB phase but observed even in the upper range of a smectic phase that forms just below the NTB state. The coexistence of smectic layering and the heliconical order indicates a layered (SmATB) phase wherein the rigid units of the dimers are tilted with respect to the smectic layer normal in order to accommodate the bent conformation of the dimers and the tilt direction rotates along the heliconical axis.

Properties of Iron Primary Cosmic Rays: Results from the Alpha Magnetic Spectrometer

We report the observation of new properties of primary iron (Fe) cosmic rays in the rigidity range 2.65 GV to 3.0 TV with 0.62×10^{6} iron nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. Above 80.5 GV the rigidity dependence of the cosmic ray Fe flux is identical to the rigidity dependence of the primary cosmic ray He, C, and O fluxes, with the Fe/O flux ratio being constant at 0.155±0.006. This shows that unexpectedly Fe and He, C, and O belong to the same class of primary cosmic rays which is different from the primary cosmic rays Ne, Mg, and Si class.

Surface Localization of the Dineutron in ^{11}Li

The formation of a dineutron in the ^{11}Li nucleus is found to be localized to the surface region. The experiment measured the intrinsic momentum of the struck neutron in ^{11}Li via the (p,pn) knockout reaction at 246  MeV/nucleon. The correlation angle between the two neutrons is, for the first time, measured as a function of the intrinsic neutron momentum. A comparison with reaction calculations reveals the localization of the dineutron at r∼3.6  fm. The results also support the density dependence of dineutron formation as deduced from Hartree-Fock-Bogoliubov calculations for nuclear matter.

[The diagnostic value of flow cytometry in patients with lymphoma associated hemophagocytic syndrome]

Objective: To evaluate the reliability of flow cytometry (FCM) for diagnosing lymphoma associated hemophagocytic syndrome (LAHS). Method: The clinical data in 57 patients with hemophagocytic lymphohistiocytosis (HLH)were retrospective analyzed at Peking University Shenzhen Hospital from July 2010 to July 2019. All patients were performed bone marrow FCM and bone marrow pathological examination before final diagnoses were made. The golden diagnosis criterion was based on clinical, biochemical and histopathological evidence, which was regarded as the standard to evaluate the sensitivity and specificity of FCM analysis in diagnosing LAHS. Results: Among 57 cases, 36 cases were eventually diagnosed with LAHS, including 15 B-cell lymphoma(14 diffuse large B-cell lymphoma, 1 B-cell lymphoma with reactive T-cell hyperplasia), 13 aggressive NK/T cell lymphoma/leukemia, 2 cases of gamma-delta T-cell lymphoma, 4 angioimmunoblastic T-cell lymphoma, 1 enteropathy-associated peripheral T-cell lymphoma and 1 anaplastic T-cell lymphoma. Lymphoma cells in bone marrow were detected in all patients by FCM except one ENTCL patient. The sensitivity and the specificity of FCM in LASH compared to bone marrow biopsy were 97.2%(P=0.014)and 90.5%(P=0.488) respectively. In the other 21 non-LAHS patients, T cell receptor Vβ (TCRVβ) rearrangement was detected in 2 patients with Epstein-Barr virus (EBV) associated primary HLH. Conclusions: FCM effectively detects lymphoma cells in bone marrow of lymphoma patients with LHL, suggesting that FCM could be an important indicator for the diagnosis of LAHS. FCM also has the advantage in differentiating LAHS from other HLH.

Clone, expression and plasminogen binding property of three fructose-1,6-bisphosphate aldolases from Clonorchis sinensis

Fructose-1,6-bisphosphate aldolase (FbA), a well characterized glycometabolism enzyme, has been found to participate in other important processes besides the classic catalysis. To understand the important functions of three fructose-1,6-bisphosphate aldolases from Clonorchis sinensis (CsFbAs, CsFbA-1/2/3) in host-parasite interplay, the open reading frames of CsFbAs were cloned into pET30a (+) vector and the resulting recombinant plasmids were transformed into Escherichia coli BL21 (DE3) for expression of the proteins. Purified recombinant CsFbAs proteins (rCsFbAs) were approximately 45.0 kDa on 12% SDS-PAGE and could be probed with each rat anti-rCsFbAs sera by western blotting analysis. ELISA and ligand blot overlay indicated that rCsFbAs of 45.0 kDa as well as native CsFbAs of 39.5 kDa from total worm extracts and excretory-secretory products of Clonorchis sinensis (CsESPs) could bind to human plasminogen, and the binding could be efficiently inhibited by lysine analog ε-aminocaproic acid. Our results suggested that as both the components of CsESPs and the plasminogen binding proteins, three CsFbAs might be involved in preventing the formation of the blood clot so that Clonorchis sinensis could acquire enough nutrients from host tissue for their successful survival and colonization in the host. Our work will provide us with new information about the biological function of three CsFbAs and their roles in hostparasite interplay.

Antifungal activity screening for mint and thyme essential oils against Rhizopus stolonifer and their application in postharvest preservation of strawberry and peach fruits

AIMS

With a goal to identify specific essential oils that can control postharvest Rhizopus rot on strawberry and peach fruits, we performed screening for 26 essential oils based on their antifungal activity against Rhizopus stolonifer in vitro and investigated the underlying mechanism.

METHODS AND RESULTS

Mentha spicata (Ms), Mentha piperita (Mp), Thymus vulgaris CT carvacrol (Tc) and Thymus vulgaris CT thymol (Tt) exhibited strong inhibition on R. stolonifer growth in the screening. These essential oils increased plasma membrane permeability of R. stolonifer and resulted in the outflow of intercellular electrolyte, nucleic acid, protein and soluble sugar. Morphology of R. stolonifer mycelia was greatly altered by these essential oils. Hyphae treated by these essential oils exhibited high accumulation of superoxide anion and malonaldehyde. Combination of these essential oils in commercial package reduced Rhizopus rot on strawberry and peach fruits, with Mp showing the strongest efficiency.

CONCLUSION

Ms, Mp, Tc and Tt essential oils inhibited R. stolonifer growth by targeting its plasma membrane and reduced Rhizopus rot on strawberry and peach fruits.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides potential applications of natural plant extract, as alternatives to tradition fungicides, to control postharvest decay on fruits and vegetables.

Inactivation of TMEM106A promotes lipopolysaccharide-induced inflammation via the MAPK and NF-κB signaling pathways in macrophages

Pattern recognition receptors, such as Toll-like receptors (TLRs), play an important role in the host defense against invading microbial pathogens. Their activation must be precisely regulated, as inappropriate activation or overactivation of TLR signaling pathways may result in inflammatory disorders, such as septic shock or autoimmune diseases. TMEM106A is a type II transmembrane protein constitutively expressed in macrophages. Our current study demonstrated that TMEM106A levels were increased in macrophages upon lipopolysaccharide (LPS) stimulation, as well as in the peripheral monocytes of patients with sepsis. Tmem106a knockout mice were more sensitive to lipopolysaccharide (LPS)-induced septic shock than wild-type mice. Further experiments indicated that Tmem106a ablation enhanced the expression of CD80, CD86 and major histocompatibility complex (MHC)-II in mouse macrophages upon LPS stimulation, accompanied with up-regulation of tumor necrosis factor (TNF)-α, interleukin (IL)-6, interferon (IFN)-β and inducible nitric oxide synthase (iNOS), indicating the activation of macrophages and polarization towards the M1 inflammatory phenotype. Moreover, elevated mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) signaling were found to be involved in the LPS-induced inflammatory response in Tmem106a^-/- macrophages. However, this effect was largely abrogated by macrophage deletion in Tmem106a^-/- mice. Therefore, deficiency of Tmem106a in macrophages may enhance the M1 polarization in mice, resulting in inflammation. This suggests that TMEM106A plays an important regulatory role in maintaining macrophage homeostasis.

[Preliminary observation on the treatment of primary pterygium with modified conjunctival transplantation and amniotic membrane transplantation combined with use of interferon eye drops]

Objective: To observe the clinical effect of modified conjunctival transplantation and amniotic membrane transplantation combined with use of interferon (IFN) alpha-2b eye drops in the treatment of primary pterygium. Methods: This was a prospective case-control study. Patients with primary pterygium were treated from June 1, 2018 to December 31, 2018 in the Department of Ophthalmology, Beijing Tongren Hospital, and they were divided into two groups (the experimental group and the control group) by the method of randomized block design. Patients in the experimental group received modified conjunctival transplantation and amniotic membrane transplantation combined with use of IFN alpha-2b eye drops, while patients in the control group received pterygium resection combined with conjunctival autograft transplantation. The pterygium type and size were observed before operation, while visual acuity, intraocular pressure and anterior segment details were recorded either. The follow-up was done at 1 week, 2 weeks, 1 month, 3 months, 6 months and 12 months after operation. The visual acuity, corneal epithelial defect, and pterygium recurrence were observed. All data in this manuscript are enumeration data, the expected frequency of pterygium type distribution in the two groups was more than 5, and the chi square test was used, fisher's exact test was used to compare the other data between the two groups. Results: Seventy patients (77 eyes) with pterygium were in this study, including 30 males and 40 females, aged from 50-70 years old. There were 35 cases (38 eyes) in the experimental group and 35 cases (39 eyes) in the control group. 12 months after operation there were 54 cases (60 eyes) including 28 cases (30 eyes) in the experimental group and 26 cases (30 eyes) in the control group with complete data. The corneal epithelium defects of 1 eye in each group was repaired within 7-14 days after operation, and the rest eyes were completely repaired within 7 days after operation. There was no significant difference in the distribution of corneal epithelial healing between the two groups (P= 1.00). There was no significant difference between the two groups in the number of eyes distribute with decreased visual acuity (2 eyes in each group), stable visual acuity (15 eyes in the experimental group and 23 eyes in the control group), and improved visual acuity (13 eyes in the experimental group and 5 eyes in the control group) (P=0.053). There was no recurrence in the two groups at 12 months after surgery, and there was no significant difference between the two groups in the number of patients with conjunctival hyperplasia of grades 1, 2 and 3 (P=0.405). Conclusions: Modified conjunctival transplantation and amniotic membrane transplantation combined with use of IFN alpha-2b eye drops got low recurrence rate for primary pterygium and less damage to the healthy conjunctival tissue. This combined treatment strategy provides a new choice for the treatment of pterygium. (Chin J Ophthalmol, 2020, 56: 768-773).

LncRNA GAS5 overexpression alleviates the development of osteoporosis through promoting osteogenic differentiation of MSCs via targeting microRNA-498 to regulate RUNX2

OBJECTIVE

The aim of this study was to elucidate whether long non-coding RNA (lncRNA) GAS5 could target microRNA-498 to regulate RUNX2, thus alleviating the development of osteoporosis.

PATIENTS AND METHODS

Human multipotential mesenchymal stem cells (hMSCs) were isolated from bone marrow of osteoporosis patients or healthy controls. Quantitative Real-time polymerase chain reaction (qRT-PCR) was performed to detect the expression levels of GAS5, microRNA-498 and RUNX2 in hMSCs of osteoporosis patients and controls, respectively. Meanwhile, the protein level of RUNX2 in hMSCs was detected by Western blot. Furthermore, alkaline phosphatase (ALP) activity assay and ALP staining were performed to evaluate the degree of osteogenic differentiation under the control of GAS5, microRNA-498 and RUNX2.

RESULTS

MicroRNA-498 was highly expressed in hMSCs derived from osteoporosis patients, whereas GAS5 and RUNX2 were lowly expressed. GAS5 overexpression significantly increased ALP activity and promoted osteogenic differentiation of hMSCs derived from osteoporosis patients. Meanwhile, GAS5 significantly promoted osteogenic differentiation by mediating microRNA-498 expression to up-regulate RUNX2. Co-overexpression of GAS5 and microRNA-498 could remarkably reverse the increase of RUNX2 expression. Besides, RUNX2 overexpression markedly elevated ALP activity.

CONCLUSIONS

LncRNA GAS5 is lowly expressed in patients with osteoporosis. Overexpression of GAS5 promotes osteogenic differentiation of hMSCs through regulating microRNA-498 to up-regulate RUNX2 expression, thus alleviating the development of osteoporosis.

[Predictive factors of poor prognosis in children with acute kidney injury treated with renal replacement therapy]

Objective: To investigate the predictive factors of poor prognosis in children with acute kidney injury (AKI) treated with renal replacement therapy (RRT). Methods: In this retrospective case-control study, the clinical data were collected from 134 pediatric patients (82 male, 52 female) with AKI treated with RRT in six tertiary hospitals from May 2015 to June 2018. According to the serum creatinine level at discharge, the patients were divided into the favorable outcome group and unfavorable outcome group. The data of sex, age, primary diseases, AKI stage, time from diagnosis of AKI to start of RRT (h) and whether to start RRT within 24 hours, urine volume and complications between the two groups were compared. Continuous variables were compared by t test and Mann-Whitney U test, and percentage or proportions were compared by Chi square test. The predictive factors of adverse prognosis were analyzed by using univariate and unconditional binary logistic regression analysis. Results: The average age of the 134 AKI patients was (6±4) years. There were 114 patients (85.0%) in the favorable outcome group and 20 patients (15.0%) in the unfavorable outcome group. No statistically significant differences were found between the two groups in terms of sex (χ(2)=2.596, P=0.107), age (t=0.718, P=0.474), primary disease (χ(2)=2.076, P=0.722), AKI stage (χ(2)=0.004, P=0.998), time from diagnosis of AKI to start RRT (h) (P=0.745), whether to start RRT within 24 hours (χ(2)=0.016, P=0.899), urine volume (χ(2)=3.118, P=0.374), fluid overload (χ(2)=0.014, P=0.905), multiple organ dysfunction syndrome (MODS) (χ(2)=2.972, P=0.085), acidosis (χ(2)=3.204, P=0.073), hyperkalemia (χ(2)=2.829, P=0.093), the level of blood urea nitrogen (t=1.351, P=0.179) and serum creatinine (P=0.901) at the beginning of RRT. In the unfavorable outcome group, the proportion of patients with mechanical ventilation (45.0% (9/20) vs. 12.3% (14/114), χ(2)=12.811, P<0.01) and the incidence of extra organ injury (≥3) (30.0% (6/20) vs. 10.5% (12/114), χ(2)=6.365, P=0.041) were higher than those in the favorable outcome group. Logistic regression analysis showed that mechanical ventilation (OR=12.540, 95%CI: 3.376-46.577, P<0.01) and hyperkalemia (OR=4.611, 95%CI: 1.265-16.805, P=0.021) were the predictive factors of poor prognosis in patients with AKI treated with RRT. Conclusion: Mechanical ventilation and hyperkalemia may predict a poor prognosis in AKI patients treated with RRT.