[The 491st case: thrombocytosis, gastrointestinal hemorrhage, intestinal perforation]

Essential thrombocythemia (ET) is a chronic myeloproliferative neoplasm (MPN) featured by clonal proliferation of platelets, thrombosis and hemorrhage. Portal hypertension is a serious complication of ET associated with poor prognosis. We report a patient with ET complicated with acute upper gastrointestinal hemorrhage and intestinal perforation due to portal hypertension. She had an uneventful recovery after surgical and endoscopic treatment.

Toxicity screening of air extracts representing different source sectors in the Greater Toronto and Hamilton areas: In vitro oxidative stress, pro-inflammatory response, and toxicogenomic analysis

In the present study, the suitability and sensitivity of different in vitro toxicity endpoints were determined to evaluate and distinguish the specific contributions of polycyclic aromatic carbon (PAC) mixtures from various sites in Toronto (Canada), to pulmonary toxicity. Air samples were collected for two-month periods from April 2014 to March 2015 from one location, and from August 2016 to August 2017 from multiple locations reflecting different geographical areas in Toronto, and the Greater Toronto Area, with varying source emissions including background, traffic, urban, industrial and residential sites. Relative concentrations of PACs and their derivatives in these air samples were characterised. In vitro cytotoxicity, pro-inflammatory, and oxidative stress assays were employed to assess the acute pulmonary effects of urban-air-derived air pollutants. In addition, global transcriptional profiling was utilized to understand how these chemical mixtures exert their harmful effects. Lastly, the transcriptomic data and the chemical profiles for each site and season were used to relate the biological response back to individual constituents. Site-specific responses could not be derived; however, the Spring season was identified as the most responsive through benchmark concentration analysis. A combination of correlational analysis and principal component analysis revealed that nitrated and oxygenated polycyclic aromatic hydrocarbons (PAHs) drive the response at lower concentrations while specific PAHs drive the response at the highest concentration tested. Unsubstituted PAHs are the current targets for analysis as priority pollutants. The present study highlights the importance of by-products of PAH degradation in the assessment of risk. The study also demonstrates the usefulness of in vitro toxicity assays to derive meaningful data in support of risk assessment.

Magnonic Unidirectional Spin Hall Magnetoresistance in a Heavy-Metal-Ferromagnetic-Insulator Bilayer

We report the observation of the unidirectional spin Hall magnetoresistance (USMR), which depends on the current or magnetization direction, in heavy-metal-ferromagnetic-insulator bilayer, Pt-Y_{3}Fe_{5}O_{12} (YIG). This USMR is apparently not caused by the mechanisms established in metallic bilayer, in which the ferromagnetic layer is required to be electrically conductive. From the magnetic field, current, temperature, and YIG thickness dependent measurements, the USMR is attributed to the asymmetric magnon creation and annihilation induced by the spin-orbit torque. This asymmetry and the resultant USMR are further revealed by the micromagnetic simulations combined with the spin-orbit torque and the spin drift-diffusion model. Our finding exhibits a nonlinear manipulation of magnons with the charge current.

Use of MRI signal intensity ratio to differentiate between autoimmune pancreatitis and pancreatic ductal adenocarcinoma

AIM

To evaluate the accuracy of the lesion-to-erector spinae signal intensity ratio (SIR) on magnetic resonance imaging (MRI) for distinguishing autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDA).

MATERIALS AND METHODS

The MRI data of 21 patients with AIP and 27 patients with PDA were analysed retrospectively, and the signal intensity in pancreatic lesions and erector spinae muscles at the same level on T2-weighted imaging (T2WI), arterial phase (AP) imaging, and delayed phase (DP) imaging was measured for calculation of SIRs.

RESULTS

The mean SIRs of the pancreatic lesions and erector spinae from T2WI, AP, and DP images of AIP patients were 0.96, 1.27, and 1.42, respectively, while those of PDA patients were 1.35, 0.80, and 0.91, respectively. The differences in the SIRs between the AIP and PDA groups were statistically significant (p<0.001), with corresponding area under curve (AUC) values of 0.925, 0.906, and 0.961, respectively. The optimal cut-off values for the SIRs on T2WI, AP and DP images were 1.21, 1.01, and 1.08, respectively. SIR values < 1.21 on T2WI, >1.01 on AP imaging, and >1.08 on DP imaging identified AIP with sensitivities of 85.7%, 90.5%, and 90.5%, respectively, and specificities of 81.5%, 74.6%, and 81.5%, respectively. The AUC values for SIRs did not differ significantly between T2WI and DP imaging or AP and DP imaging (Z = 0.778, p=0.436; Z = 1.279, p=0.201).

CONCLUSION

The SIRs of pancreatic lesions and erector spinae on T2WI, AP, and DP images can be used to differentiate AIP from PDA.

Trem1 Induces Periodontal Inflammation via Regulating M1 Polarization

Periodontitis is a chronic inflammatory condition characterized by destruction of nonmineralized and mineralized connective tissues. This study evaluated the role of Trem1 (triggering receptors expressed on myeloid cells 1) in periodontitis by influencing polarization of M1 macrophages through the STAT3/HIF-1α signaling pathway. Trem1 was significantly upregulated in the gingival tissues of patients with periodontitis, as identified by high-throughput RNA sequencing, and positively correlated with levels of M1 macrophage-associated genes. The results of flow cytometry, Western blotting, and reverse transcription quantitative polymerase chain reaction showed that knockdown of Trem1 in RAW 264.7 cells decreased polarization of M1 macrophages and increased polarization of M2 macrophages, while overexpression of Trem1 exerted an opposite effect. Furthermore, a mouse model of Trem1 knockout periodontitis exhibited limited infiltration of macrophages and decreased expression levels of M1 macrophage-associated genes in periodontitis lesions and bone marrow-derived macrophages. Importantly, we found that Trem1 could regulate polarization of M1 macrophages through STAT3/HIF-1α signaling as evidenced by RNA sequencing. Moreover, inhibition of Trem1 and HIF-1α could suppress the expression level of proinflammatory cytokine (interleukin 1β) and upregulate the expression level of anti-inflammatory cytokine (interleukin 10) in periodontitis. Collectively, we identified that the Trem1/STAT3/HIF-1α axis could regulate polarization of M1 macrophages and is a potential candidate in the treatment of periodontitis.

[CDK1, CCNB1 and NDC80 are associated with prognosis and progression of hepatitis B virus-associated hepatocellular carcinoma: a bioinformatic analysis]

OBJECTIVE

To identify the key genes involved in the transformation of hepatitis B virus (HBV) into hepatocellular carcinoma (HCC) and explore the underlying molecular mechanisms.

METHODS

We analyzed the mRNA microarray data of 119 HBV-related HCC tissues and 252 HBV-related non-tumor tissues in GSE55092, GSE84044 and GSE121248 from the GEO database, and the "sva" R package was used to remove the batch effects. Integration analysis was performed to identify the differentially expressed genes (DEGs) in HBV-related liver cancer and liver tissues with HBV infection. The significant DEGs were functionally annotated using GO and KEGG analyses, and the most important modules and hub genes were explored with STRING analysis. Kaplan-Meier and Oncomine databases were used to verify the HCC gene expression data in the TCGA database to explore the correlations of the hub genes with the occurrence, progression and prognosis of HCC. We also examined the expressions of the hub genes in 17 pairs of surgical specimens of HCC and adjacent tissues using RT-qPCR.

RESULTS

We identified a total of 121 DEGs and 3 genetic markers in HCC (P < 0.01). These DEGs included cyclin1 (CDK1), cyclin B1 (CCNB1), and nuclear division cycle 80 (NDC80), which participated in cell cycle, pyrimidine metabolism and DNA replication and were highly correlated (P < 0.05). Analysis of the UALCAN database confirmed high expressions of these 3 genes in HCC tissues, which were correlated with a low survival rate of the patients, as shown by Kaplan-Meier analysis of the prognostic data from the UALCAN database. CDK1, CCNB1 and NDC80 were all correlated with the clinical grading of HCC (P < 0.05). The results of RT-qPCR on the surgical specimens verified significantly higher expressions of CDK1, CCNB1 and NDC80 mRNA in HCC tissues than in the adjacent tissues.

CONCLUSION

CDK1, CCNB1 and NDC80 genes can be used as prognostic markers of HBV-related HCC and may serve as potential targets in preclinical studies and clinical treatment of HCC.

Clinical benefits of TNF-α inhibitors in Chinese adult patients with NLRP3-associated autoinflammatory disease

BACKGROUND

Nucleotide-binding oligomerization domain-like receptor family, pyrin domain containing 3 (NLRP3)-associated autoinflammatory disease (NLRP3-AID) is a rare, heterogeneous disease entity associated with mutations in NLRP3. Biologic therapy for NLRP3-AID yields diverse results.

OBJECTIVES

We aimed to evaluate the clinical features and outcomes of Chinese adult patients with NLRP3-AID who were treated with tumour necrosis factor (TNF)-α inhibitors.

METHODS

Five patients with NLRP3-AID were diagnosed and treated with TNF-α inhibitors at Peking Union Medical College Hospital between 2017 and 2020 and were followed up for 6 to 12 months. All patients were systematically studied for treatment outcomes, including clinical manifestations and inflammatory markers.

RESULTS

All five adult NLRP3-AID patients were Chinese Han, and four patients were males. The mean age at disease onset was 4.2 ± 4.1 years, and the mean time of diagnosis delay was 19.8 ± 6 years. All patients received TNF-α inhibitors with or without methotrexate/prednisone. During follow-up, all patients achieved remarkable clinical remission of skin lesions and polyarthritis and showed improvements in acute-phase reactants, inflammatory cytokines, patient visual analogue scale, physician global assessment and 36-item Short Form (SF-36).

CONCLUSIONS

Early diagnosis and effective therapy for NLRP3-AID are essential for avoiding irreversible organ damage. TNF-α inhibitors might serve as a therapeutic alternative for patients with NLRP3-AID who have unsatisfactory responses or no access to interleukin-1 inhibitors.

Correlation between culprit vessel/tirofiban and reperfusion bradyarrhythmia in patients with ST-segment elevation myocardial infarction after emergency PCI

OBJECTIVE

To evaluate the correlation between culprit vessel/tirofiban and reperfusion bradyarrhythmia in patients with ST-segment elevation myocardial infarction (STEMI) after emergency percutaneous coronary intervention (PCI).

PATIENTS AND METHODS

A total of 123 STEMI patients undergoing emergency PCI in our hospital from September 2018 to September 2019 were selected and divided into the reperfusion arrhythmias (RA) group (50 cases) and non-RA group (NRA, 73 cases) according to whether RA occurring during PCI. The baseline data such as age and underlying disease were statistically analyzed. Then, the differences were compared between the two groups. According to whether reperfusion bradyarrhythmia (RB) occurring during PCI, 123 STEMI patients were divided into the RB group (63 cases) and non-RB group (60 cases). The relation between culprit vessel/tirofiban and RB was analyzed. ROC curves analysis and multivariate logistic regression were conducted for the risk factors of RA and RB.

RESULTS

Among 123 patients with STEMI after PCI treatment, 73 patients had RA (59.35%), including RB 63 cases and tachyarrhythmia 10 cases. Results of single factor analysis showed that there was statistical significance in 3 factors including the patient age, infarction area and vascular blood flow TIMI classification between RA group and NRA group (p<0.05). ROC curve analysis indicated that the continuous variable patent ages had predictive value in the prevalence of RA, which resulting in an AUC 0.624 and a cut-off pointed age 57 (sensitivity 72.60, specificity 52.00). Multivariate regression analysis showed that the patient age (>57 years old), infarction area in inferior wall and grade 0 lesion vascular blood flow TIMI classification in RA group was significantly higher than that in NRA group (p<0.05). Tirofiban was not associated with RB in STEMI patients treated with emergency PCI, while culprit vessel was statistically significant between RB group and NRB group (p<0.05). Multivariate regression analysis indicated that culprit vessel of the right coronary artery and grade 0 lesions vascular blood flowed TIMI classification was independent risk factors to occurring RB in the STEMI patients with emergency PCI.

CONCLUSIONS

Tirofiban was not associated with RB in STEMI patients treated with emergency PCI. However, it may increase the risk of RB development when the culprit vessel is the right coronary artery. Therefore, timely corresponding treatments and reduction of reperfusion damage are of great significance for those patients.

A novel micro-tensile system for full-field deformation measurement of thin films

We propose a novel micro-tensile system fit for mechanical property characterization of low-dimensional materials. The micro-tensile system was integrated with a micro-tensile apparatus driven by a piezoelectric transducer (PZT) and an optical microscope. The displacement provided by the PZT actuator was amplified by a lever structure on the micro-tensile apparatus. A stalloy was designed to transmit the displacement and reduce the mechanical resistance to the PZT actuator. Quantitative analysis was conducted for the designed apparatus. A calibration experiment was performed based on the micro-scale digital image correlation under the optical microscope. To validate the feasibility, the PET film specimen with a V-notch was tested by the proposed system. The results indicate that the proposed micro-tensile system is reliable and powerful.

[Evaluation on applicationof virtual reality technology in dental implant process training]

Objective: To explore the application effect and evaluation of virtual reality technology in oral implant therapy training. Methods: In November 2018, one adult patient (female, 36 years old) with missing right mandibular first molar was treated in the Department of Implantology, School and Hospital of Stomatology, Fujian Medical University. The three-dimensional virtual models of mandible and implant surgery tools were established, and the virtual reality software (Unity 3D 5.5.1) was imported. Combined with the virtual reality head mounted display, a virtual reality training system simulating the dental implant treatment process was independently developed. Ten refresher doctors and 20 graduate students in Department of Implantology, School and Hospital of Stomatology, Fujian Medical University from September 2018 to December 2019 were recruited as the experimental objects (no clinical experience was found). According to the level and seniority of doctors, they were randomly divided into virtual training group and conventional training control group, which made the two groups comparable, with 15 in each group. Subjective scores (including anatomical structure, surgical field of vision, cavity preparation, implant placement and process mastery) were given after the corresponding training in the two groups, and the virtual reality training system was used to test. The mesial and distal direction, buccolingual direction, depth and angle deviation of implants before and after the training were analyzed, and the differences between the two groups were compared. Results: The subjective scores of five dimensions in the virtual training group were significantly higher than those in the conventional training control group (P<0.05). In the virtual training group, the mesial and distal, buccolingual, depth and angle deviation of implants were (0.73±0.33), (0.78±0.41), (0.61±0.32) mm and 6.66°±3.87°. All of them were significantly lower than those in the control group [(0.85±0.32), (1.12±0.38), (0.89±0.24) mm and 9.68°±3.74°] (P<0.05). Conclusions: The self-developed virtual reality system of oral implant has good application effect, good operability and predictability. It can be effectively carried out in implant education and training, and it can strengthen skills of doctors, and is conducive to the practical operation.

[Genetic and clinical analysis of X-linked hypophosphatemic rickets]

Objective: To investigate the clinical and genetic features, and treatment of X-linked hypophosphatemic rickets (XLH). Methods: In this retrospective study, we reviewed the medical records of 25 pediatric patients with XLH who were admitted to Department of Endocrinology Genetics and Metabolism,Beijing Children's Hospital from January 2010 to January 2020. The clinical characteristics, PHEX gene variants, as well as clinical outcome of the patients were summarized. To analyze the correlation between genotype and phenotype, the patients were divided into different subgroups according to the location of the variants, including N-terminal-located vs. C-terminal-located variant, and Zn-binding domain exon 17 or 19 variant vs. non-exon 17 or 19 variant. The age at onset, height standard deviation score (HtSDS), intercondylar or intermalleolar distance, fasting serum phosphorus, and HtSDS and intercondylar or intermalleolar distance at the final follow-up were compared by rank sum test or t text. Results: Among the 25 children with XLH, 8 were boys and 17 were girls. The median age of onset was 1.2 (1.0, 1.8) years, and the median age of diagnosis was 2.5 (1.5, 4.3) years. The main clinical manifestations were abnormal gait and lower limb deformity. The HtSDS was -2.0(-3.2, -0.8), and the intercondylar or intermalleolar distance was 4.5 (3.0, 6.0) cm. The fasting serum phosphorus level was 0.8 (0.7, 0.9) mmol/L, while the serum alkaline phosphatase level was (721±41) U/L and the serum calcium level was (2.5±0.1) mmol/L. Three patients (12%) had parathyroid hormone levels above the upper limit of the normal range. Twenty-five patients (100%) showed radiographic changes of active rickets. Nephrocalcinosis was found in 2 cases (9%). Twenty-four different PHEX variations were detected in 25 patients, among whom 11 (44%) had not been reported previously. No hot spot variation was found. No statistical differences (all P>0.05) were identified in clinical features and outcomes either in comparing patients with N-terminal (21 cases) and C-terminal (4 cases) variants, or in comparing patients with variant located in exon 17 or 19 (4 cases) or not (21 cases). Twenty-four cases (96%) were treated regularly with phosphate supplements and active vitamin D. After 2.7 (1.6, 5.0) years of follow-up, clinical symptoms were relieved in 96% (24/25) of the patients. The HtSDS after treatment had no significant difference compared to that before treatment (-2.0(-3.2, -0.8) vs.-2.0(-2.8, -1.1),Z =-0.156, P>0.05), while the intercondylar or intermalleolar distance after treatment was significantly reduced compared to that before treatment (4.5(3.0, 6.0) vs. 1.5(0, 3.3) cm, Z =-3.043, P<0.05). Bone X-rays were reexamined in 17 cases after treatment, and radiographic signs of rickets were improved. Eighteen cases had secondary hyperparathyroidism and 7 cases had nephrocalcinosis. Conclusions: The main clinical manifestations of XLH are abnormal gait, lower limb deformity and short stature. A high proportion of novel variations of PHEX gene but no hot spot variation neither genotype-phenotype correlation are found. Regular treatment with phosphate supplements and active vitamin D can significantly improve the symptoms except for the height. However, the rate of adverse events including secondary hyperparathyroidism and nephrocalcinosis seems to be high.

[Surveillance of human soil-transmitted nematodiasis in Jurong City from 2016 to 2020]

OBJECTIVE

To investigate the prevalence of soil-transmitted nematode human infections in Jurong City from 2016 to 2020, so as to provide the scientific evidence for formulating the control strategy.

METHODS

During the period from 2016 to 2020, the permanent residents at ages of over 3 years living in Jurong City were selected as the study subjects. Stool samples were collected for the detection of soil-transmitted nematode eggs using the modified Kato-Katz thick smear method (two detections for one stool sample), and the species of hookworm was identified in stool-positive stool samples using the culture method. The prevalence and intensity of soil-transmitted nematode infections were calculated, and the change of the infection prevalence among years was examined using the Cochran-Armitage test for trend.

RESULTS

A total of 10 011 people-time populations were detected for soil-transmitted nematode infections in Jurong City from 2016 to 2020, and 56 egg-positives were identified, with mean prevalence of 0.56%. The prevalence of soil-transmitted nematode human infections appeared a tendency towards a decline year by year in Jurong City (χ²_trend = 5.15, P < 0.01). The mean prevalence of hookworm, Ascaris lumbricoides and Trichuris trichiura infections was 0.44%, 0.11% and 0.20% in Jurong City from 2016 to 2020, respectively, and individuals with hookworm infections accounted for 78.57% of all cases with soil-transmitted nematode infections. Single parasite (98.21%) and mild infection were pre-dominant in individuals with soil-transmitted nematode infections, and no multiple infections were seen after 2016.

CONCLUSIONS

The prevalence of human soil-transmitted nematodiasis is low in Jurong City. Based on reinforcement of soil-transmitted nematodiasis surveillance, an increase in the health education investment is required to consolidate the control achievements.

Long non-coding RNA PLAC2 suppresses the survival of gastric cancer cells through down-regulating C-Myc

OBJECTIVE

The aim of this study was to explore the effects of long non-coding ribonucleic acid (lncRNA) placenta-specific protein 2 (PLAC2) on the biological behaviors of gastric cancer (GC) cells by regulating the expression of c-Myc gene and its mechanism.

PATIENTS AND METHODS

The expression of PLAC2 in GC tissues and different GC cell lines was detected via quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR). The effects of PLAC2 on apoptosis and cycle, migration, and invasion of GC cells were detected using flow cytometry, wound healing assay, and transwell assay, respectively. After interference in PLAC2 expression, the changes in c-Myc expression were determined through qRT-PCR and Western blotting.

RESULTS

The expression level of PLAC2 was downregulated in 38 out of 45 cases of GC tissues compared with that in normal gastric tissues, and it also declined in GC cells. The results of flow cytometry showed that after overexpression of PLAC2, the cell cycle was arrested in the G1/G0 phase, and the apoptosis rate was increased. The results of wound healing assay and transwell assay revealed that both migration and invasion of GC cells were inhibited. After overexpression of PLAC2, the mRNA and protein expression levels of c-Myc declined.

CONCLUSIONS

LncRNA PLAC2 affects the biological behaviors of GC cells by regulating the expression of c-Myc gene.

Measurement of the Cosmic Ray Helium Energy Spectrum from 70 GeV to 80 TeV with the DAMPE Space Mission

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.

[A multi-center retrospective study of perioperative chemotherapy for gastric cancer based on real-world data]

Objective: To explore the effect of perioperative chemotherapy on the prognosis of gastric cancer patients under real-world condition. Methods: A retrospective cohort study was carried out. Real world data of gastric cancer patients receiving perioperative chemotherapy and surgery + adjuvant chemotherapy in 33 domestic hospitals from January 1, 2014 to January 31, 2016 were collected. Inclusion criteria: (1) gastric adenocarcinoma was confirmed by histopathology, and clinical stage was cT2-4aN0-3M0 (AJCC 8th edition); (2) D2 radical gastric cancer surgery was performed; (3) at least one cycle of neoadjuvant chemotherapy (NAC) was completed; (4) at least 4 cycles of adjuvant chemotherapy (AC) [SOX (S-1+oxaliplatin) or CapeOX (capecitabine + oxaliplatin)] were completed. Exclusion criteria: (1) complicated with other malignant tumors; (2) radiotherapy received; (3) patients with incomplete data. The enrolled patients who received neoadjuvant chemotherapy and adjuvant chemotherapy were included in the perioperative chemotherapy group, and those who received only postoperative adjuvant chemotherapy were included in the surgery + adjuvant chemotherapy group. Propensity score matching (PSM) method was used to control selection bias. The primary outcome were overall survival (OS) and progression-free survival (PFS) after PSM. OS was defined as the time from the first neoadjuvant chemotherapy (operation + adjuvant chemotherapy group: from the date of operation) to the last effective follow-up or death. PFS was defined as the time from the first neoadjuvant chemotherapy (operation + adjuvant chemotherapy group: from the date of operation) to the first imaging diagnosis of tumor progression or death. The Kaplan-Meier method was used to estimate the survival rate, and the Cox proportional hazards model was used to evaluate the independent effect of perioperative chemo therapy on OS and PFS. Results: 2 045 cases were included, including 1 293 cases in the surgery+adjuvant chemotherapy group and 752 cases in the perioperative chemotherapy group. After PSM, 492 pairs were included in the analysis. There were no statistically significant differences in gender, age, body mass index, tumor stage before treatment, and tumor location between the two groups (all P>0.05). Compared with the surgery + adjuvant chemotherapy group, patients in the perioperative chemotherapy group had higher proportion of total gastrectomy (χ(2)=40.526, P<0.001), smaller maximum tumor diameter (t=3.969, P<0.001), less number of metastatic lymph nodes (t=1.343, P<0.001), lower ratio of vessel invasion (χ(2)=11.897, P=0.001) and nerve invasion (χ(2)=12.338, P<0.001). In the perioperative chemotherapy group and surgery + adjuvant chemotherapy group, 24 cases (4.9%) and 17 cases (3.4%) developed postoperative complications, respectively, and no significant difference was found between two groups (χ(2)=0.815, P=0.367). The median OS of the perioperative chemotherapy group was longer than that of the surgery + adjuvant chemotherapy group (65 months vs. 45 months, HR: 0.74, 95% CI: 0.62-0.89, P=0.001); the median PFS of the perioperative chemotherapy group was also longer than that of the surgery+adjuvant chemotherapy group (56 months vs. 36 months, HR=0.72, 95% CI:0.61-0.85, P<0.001). The forest plot results of subgroup analysis showed that both men and women could benefit from perioperative chemotherapy (all P<0.05); patients over 45 years of age (P<0.05) and with normal body mass (P<0.01) could benefit significantly; patients with cTNM stage II and III presented a trend of benefit or could benefit significantly (P<0.05); patients with signet ring cell carcinoma benefited little (P>0.05); tumors in the gastric body and gastric antrum benefited more significantly (P<0.05). Conclusion: Perioperative chemotherapy can improve the prognosis of gastric cancer patients.

[Molecular-related epidemic characteristics of influenza A (H3N2) viruses in Guangzhou, 2019]

Objective: To isolate the influenza A (H3N2) viruses from different sources in Guangzhou in 2019 and analyze these viruses' evolution and variation characteristics. Methods: The hemagglutinin (HA) and neuraminidase (NA) genes of H3N2 isolates from outpatient monitoring, influenza outbreaks, and inpatient severe cases in Guangzhou in 2019 were sequenced. Bioinformatics software analyzed the variations and evolution characteristics of HA and NA genes. Results: The epidemic peaks of influenza A (H3N2) viruses were made up of period Ⅰ (from January to August) and period Ⅱ (from November to December). The positive rate of influenza A (H3N2) in males was 13.46% (703/5 221), which was higher than that in females (11.50%, 510/4 435) (χ²=8.43,P=0.00). The group's positive rate of 10-20 years old was the highest (25.18%,665/2 641). The isolates from different sources were highly homologous and closely related to 3C.2a.1 branches, which could be further divided into three small groups of Group 1-3. Gene recombination was observed between different branches. The mutations of HA antigen sites gradually appeared from Group 1 to Group 3, leading to new antigen drift. Variations of HA antigenic sites mainly occurred in the region of A and B. The mutations of receptor binding sites of Group 1 and Group 3 viruses occurred in the anterior and posterior walls. There were two glycosylation sites lacked on region A of HA antigen observed in the isolates of Group 2-3. Conclusions: Genetic variations of H3N2 influenza viruses in Guangzhou included gene mutations and gene recombination. Under the pressure of the vaccine, the evolution of viruses was rapid. Therefore, the monitoring of molecular-related epidemic characteristics of the H3N2 influenza virus was necessary.

Kinetic study of quantum two-stream instability by Wigner approach

Classical plasma are typically of low density and/or high temperature. Two of its basic properties are Landau damping and two-stream instabilities. When increasing the plasma density, quantum effects appear and beam-plasma interactions show behavior different from the classical cases. We revisit Landau damping and two-stream instabilities under conditions when quantum hydrodynamic and quantum kinetic theory can be applied, the latter accounting for wave-particle interactions. We find that the instability growth rate behaves as pure two-stream instability without Landau damping when the countering stream velocity exceeds a certain threshold, which differs from the classical case.

Circ_0032627 accelerates proliferation of gastric cancer cells through regulating miR-502-5p expression

OBJECTIVE

To explore the biological functions of circ_0032627 in the progression of gastric cancer (GC).

MATERIALS AND METHODS

The expression level of circ_0032627 in GC cell lines and gastric mucosal cell lines was measured via quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR). Methyl thiazolyl tetrazolium (MTT) assay, colony formation assay, and FACS were performed to examine the influences of circ_0032627 on the proliferation and apoptosis of GC cells. The relationship between circ_0032627 and micro ribonucleic acids (miRNAs) was predicted on-line using StarBase software, and whether circ_0032627 can act as the sponge of the selected miRNAs was verified via Dual-Luciferase reporter assay and qRT-PCR. Finally, MTT assay was conducted to detect the influences of the co-knockdown of circ_0032627 and the selected miRNAs on the proliferation of GC cells.

RESULTS

Compared with that in gastric mucosal cell lines, the expression level of circ_0032627 was upregulated in the selected four GC cell lines, and circ_0032627 knockdown substantially inhibited the proliferation of GC cells, but promoted their apoptosis. Circ_0032627 could act as a sponge of miR-502-5p, and miR-502-3p knockdown reversed the inhibitory effect of circ_0032627 on the proliferation of GC cells.

CONCLUSIONS

The expression level of circ_0032627 is raised in GC cells, and circ_0032627 affects the proliferation and apoptosis of GC cells by sponging miR-502-5p.

Photoinduced multistage phase transitions in Ta2NiSe5

Ultrafast control of material physical properties represents a rapidly developing field in condensed matter physics. Yet, accessing the long-lived photoinduced electronic states is still in its early stages, especially with respect to an insulator to metal phase transition. Here, by combining transport measurement with ultrashort photoexcitation and coherent phonon spectroscopy, we report on photoinduced multistage phase transitions in Ta2NiSe5. Upon excitation by weak pulse intensity, the system is triggered to a short-lived state accompanied by a structural change. Further increasing the excitation intensity beyond a threshold, a photoinduced steady new state is achieved where the resistivity drops by more than four orders at temperature 50 K. This new state is thermally stable up to at least 350 K and exhibits a lattice structure different from any of the thermally accessible equilibrium states. Transmission electron microscopy reveals an in-chain Ta atom displacement in the photoinduced new structure phase. We also found that nano-sheet samples with the thickness less than the optical penetration depth are required for attaining a complete transition.

LncRNA AWPPH accelerates the progression of non-small cell lung cancer by sponging miRNA-204 to upregulate CDK6

OBJECTIVE

This study aims to uncover the function of long non-coding RNA (lncRNA) AWPPH in the progression of non-small cell lung cancer (NSCLC) and the potential mechanism.

PATIENTS AND METHODS

AWPPH and microRNA (miRNA-204) levels in NSCLC tissues and adjacent normal tissues were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Kaplan-Meier curves were introduced for assessing overall survival in NSCLC patients expressing high or low level of AWPPH. Potential correlation between expression levels of AWPPH and miRNA-204 in NSCLC tissues was analyzed by Spearman correlation test. Through Dual-Luciferase reporter gene assay, the interaction among AWPPH, miRNA-204, and CDK6 was identified. Potential impacts of AWPPH/miRNA-204/CDK6 regulatory loop on mediating proliferative, migratory, and invasive capacities of A549 cells were evaluated through cell counting kit-8 (CCK-8) and transwell assay.

RESULTS

Upregulated AWPPH and downregulated miRNA-204 were determined in NSCLC tissues. AWPPH level was negatively correlated to overall survival in NSCLC patients and miRNA-204 level in NSCLC tissues. Silence of AWPPH attenuated proliferative, migratory, and invasive capacities in A549 cells. MiRNA-204 was the downstream gene of AWPPH. Knockdown of miRNA-204 reversed the decreased viability, migratory, and invasive rates in A549 cells with AWPPH knockdown. In addition, CDK6 was the target gene of miRNA-204. Overexpression of miRNA-204 downregulated CDK6 level in A549 cells. The attenuated proliferative, migratory, and invasive capacities in A549 cells overexpressing miRNA-204 were reversed after CDK6 overexpression.

CONCLUSIONS

LncRNA AWPPH serves as the miRNA-204 sponge to upregulate CDK6 level, thus aggravating the progression of NSCLC.

[The roles of two HIV self-testing models in promoting HIV-testing among men who have sex with men]

Objective: To evaluate the roles between two different HIV self-testing models in promoting HIV-testing among men who have sex with men (MSM). Methods: This paper focuses on two HIV self-testing service models. The first; is the online self-testing model (HIV self-testing conventional model) with the sexual health promotion network platform. The other one is an innovative HIV self-testing model (secondary distribution model), based on the previous program. The two different self-testing models, including the number of indexes and alters, the positive rate, and the demographics of indexes and alters, are compared. The influence of volunteers with or without leadership on the number of HIV self-test kits distributed or self-use is analyzed through the leadership survey scale. Results: The return rates of HIV self-testing results in the two models are 94.7%(323/341) and 99.2%(1 141/1 150), respectively, within 30 days. The proportion of alters in the secondary distribution is significantly higher (45.9%,281/612) than the conventional HIV self-testing (6.3%,20/318). In the secondary distribution model, the difference between the number of indexes and alters indicators including age, marital status, residence, sex orientation, anal sex with men in the past six months, and HIV test are statistically significant (χ² test, all P<0.05). The opinion leader of MSM has significantly impacted the promotion of HIV self-testing (P<0.05). Conclusions: Both models can promote HIV self-testing, result return, and HIV positive detection among MSM. In terms of expanding the testing and detection of HIV positive, the secondary distribution mode shows more obvious advantages, which significantly promotes a large number of MSM who have never been tested for HIV to undergo HIV testing. Influential indexes have a significant effect on increasing the HIV testing rate and promoting HIV testing among MSM.

[Changing trends of HIV testing and HIV self-testing in men who have sex with men on a gay social networking app]

Objective: To understand the changing trends of HIV testing rates, with a focus on HIV self-testing, and to evaluate the impact of HIV self-testing on expanding HIV testing among MSM in China in past few years. Methods: MSM were recruited online nationwide via a gay social networking app (Blued) from 2013 to 2016 and 2018. The survey collected information about socio-demographic backgrounds, sexual behaviors, and prior HIV testing experiences, including HIV self-testing. Trend analyses were conducted. Results: Respectively, 1 342, 1 424, 1 173, 2 105 and 699 MSM were recruited nationwide from 2013 to 2016, and in 2018. The mean age was (30.6±6.6)years in 2013 and showed a decreasing trend afterwards. The HIV testing rate was 60.0% (805/1 342) in 2013 and there was a rising trend from 2013 to 2016, and 2018 (trend Z =19.3, P <0.001), reaching a peak at 77.3% (540/699) in 2018. Further, the HIV self-testing rate increased from 19.3% (259/1 342) in 2013 to 58.1% (406/699) in 2018 (χ²=237.5, P <0.001). The proportion of MSM who had HIV self-testing among prior HIV testers significantly increased from 32.2% (259/805) to 75.2% (406/540) during the study period (trend Z =14.3, P <0.001). Conclusions: The HIV testing rate, HIV self-testing rate and proportion of men who had HIV self-testing among former HIV testers among web-based Chinese MSM showed substantial increases from 2013 to 2016,and 2018. This suggests that HIV self-testing may have a significant effect on the expansion of HIV testing coverage in MSM, and has important public health implications for HIV/AIDS prevention in China.

[Long non-coding RNA UPK1A-AS1 promotes glycolysis in hepatocellular carcinoma cells via stabilization of HIF-1α]

OBJECTIVE

To investigate the effect of long non-coding RNA UPK1A-AS1 on glycolysis of hepatocellular carcinoma cells and its underlying molecular mechanisms.

OBJECTIVE

A hepatocellular carcinoma (HCC) cell line with lentivirus-mediated stable UPK1A-AS1 overexpression and the cells infected with a negative control lentiviral vector were cultured under normoxic (21% O₂) or hypoxic (1% O₂) conditions for 24 h. The effect of UPK1A-AS1 overexpression on glycolysis of the HCC cells was examined. The expressions of glycolysis-related genes HIF1A, GLUT1, HK1, HK2 and PGK1 were detected by qRTPCR, and the effect of UPK1A-AS1 overexpression on HRE activity was detected by dual luciferase report assay. The HCC cells were treated with cycloheximide to detect the effect of UPK1A-AS1 overexpression on the stability of HIF-1α protein. Immunoprecipitation assay was used to analyze the changes in ubiquitin modification of HIF-1α protein in response to UPK1A-AS1 overexpression. The effects of UPK1A-AS1 overexpression and RNA interference of HIF-1α expression on glucose consumption, lactate production and expressions of HRE activity and glycolysis-related genes (HK1, HK2 and PGK1) were examined in the HCC cells.

OBJECTIVE

Compared with the control group, overexpression of UPK1A-AS1 significantly promoted glucose consumption and lactate production in HCC cells under both normoxic and hypoxic conditions (P < 0.05). Overexpression of UPK1A-AS1 significantly increased the expression of glycolysis-related genes including HIF1A, GLUT1, HK1, HK2 and PGK1. Upregulation of UPK1A-AS1 obviously promoted the transcriptional activity of HRE (P < 0.05). Western blotting showed that UPK1A-AS1 overexpression obviously increased the stability of HIF-1α protein and significantly reduced ubiquitin modification of HIF-1α. Downregulation of HIF-1α obviously reversed the effect of UPK1A-AS1 overexpression in promoting glucose consumption, lactate production and HRE luciferase activity. Silencing HIF-1α also suppressed the upregulation of glycolysis-related gene expressions induced by UPK1A-AS1 overexpression (P < 0.05).

OBJECTIVE

The long noncoding RNA UPK1A-AS1 upregulates the expression of glycolysis-related genes by stabilizing the expression of HIF-1α, thereby promoting glycolysis level in HCC cells.

[Analysis on antimicrobial sensitivity of Neisseria meningitidis in China from 2005 to 2019]

Objective: To analyze the antimicrobial resistance characteristics of 538 Neisseria meningitidis isolated from 2005 to 2019 in China. Method: Total of 538 Neisseria meningitidis strains collected from 30 provinces in China from 2005 to 2019. Antimicrobial susceptibility test were performed based on the standards of clinical and laboratory standardization association (CLSI) including 11 recommended antibiotics. Gradient diffusion method was used to detect the antibiotic sensitivity of Neisseria meningitidis. Results: All 538 strains were sensitive to azithromycin, meropenem, chloramphenicol, rifampicin and ceftriaxone. As to other six antibiotics, the antibiotics sensitivity rates were cefotaxime (97.4%, 524 strains), ampicillin (87.7%, 472 strains), penicillin (84.8%, 456 strains), minocycline (95.2%, 512 strains), ciprofloxacin (24.9%, 134 strains) and trimethoprim/sulfamethoxazole (11.2%, 60 strains) respectively. Conclusions: Neisseria meningitidis isolated from 2005-2019 in China were all sensitive to azithromycin, meropenem, chloramphenicol, rifampicin and ceftriaxone. It should highlight Neisseria meningitidis resistant to cefotaxime, ampicillin and penicillin. Ciprofloxacin and sulfamethoxazole are not recommended as the priority choice for clinical treatment and prophylactic medication.

[Diagnosis and follow-up of 2 cases of pediatric nephrogenic syndrome of inappropriate antidiuresis resulting from activating mutation in AVPR2 and literature review]

Objective: To analyze the clinical and genetic features, as well as the treatment outcomes of two boys with nephrogenic syndrome of inappropriate antidiuresis (NSIAD) caused by gain-of-function mutations in the V2 vasopressin receptor gene (AVPR2). Methods: The clinical manifestations, genetic testing, therapeutic interventions and the outcomes of two boys with NSIAD hospitalized in the Department of Endocrinology, Beijing Children's Hospital in April 2019 were reported. A literature search with "Nephrogenic syndrome of inappropriate antidiuresis" and "AVPR2 gene" as keywords was conducted at the China national knowledge infrastructure (CNKI), the Wanfang Data Knowledge Service Platform, PubMed and Springer Link up to May 2020. Relevant published articles were reviewed. Results: The two cases presented with chronic and severe hyponatremia with hypo-osmolality, inappropriately elevated urinary osmolality and urinary sodium levels. The onset age was 5.25-years and 2 months respectively. AVPR2 sequencing revealed a previously described hemizygous activating mutation (c.409C>T, p.R137C) in both of boys, each inherited the variant from their mother. Patient 1 limited fluid intake by himself in his daily life, intravenous and oral sodium supplementations showed no significant increase of serum sodium level. Oral furosemide increased the serum sodium level and maintained it within normal range. The serum sodium and potassium levels were in the normal range during the 1-year follow-up period with oral furosemide. The serum sodium level of Patient 2 increased with restricting fluid intake and with salt supplementation. However, after he experienced respiratory infection, the plasma sodium level decreased. Subsequently, oral anti-infection medicine and furosemide were applied. The serum sodium level increased two days later and remained at a normal range afterwards. The boy was 1 year old with normal growth. He stopped taking furosemide after 4 months while taking 1 gram of salt per day, the blood sodium level maintained at normal range. Literature search identified no reports in Chinese journals, whereas 50 publications were found in English journals. A total of 30 NSIAD probands were reported and 16 of those (53%) had childhood onset, most presented with seizures. The majority had a hotspot change at the nucleotide position of 409 in AVPR2. Nine cases had an amino acid change as R137C and five cases as R137L. Fluid restriction and oral urea intake were main treatment options, no report so far was found with oral furosemide treatment. Conclusions: NSIAD presented with hyponatremia without any other specific presentations. Genetic testing for variants in AVPR2 is helpful for early diagnosis and timely treatment. The first two cases of oral furosemide treatment were reported by the article which helped to maintain a normal serum sodium level after limiting fluid intake and supplementing sodium which showed limited effect.

[Clinical and genetic characteristics of patients with chronic enteropathy associated with SLCO2A1 gene]

Objective: To determine the clinical features and genetic characters of patients with chronic enteropathy associated SLCO2A1 gene (CEAS). Methods: Five CEAS patients diagnosed at Peking Union Medical College Hospital from January 2012 to December 2019 were enrolled in this study. The clinical manifestations, laboratory test, radiological and endoscopic findings, gene detections, treatments and prognosis of these patients were reviewed and analyzed. Results: Five male patients presented gastrointestinal symptoms after puberty, including abdominal pain, diarrhea, intermittent melena or hematochezia, incomplete bowel obstruction, anemia, hypoalbuminemia and hypokalemia. The whole gastrointestinal tract except esophagus could be involved, especially the stomach and ileum. Intestinal lesions were characterized by multiple shallow ulcers with stenosis in the layers of mucosa and submucosa. Five patients were all accompanied with primary hypertrophic osteoarthropathy (PHO), and 1 with myelofibrosis and thoracic duct dysplasia. All patients were homozygous or compound heterozygous mutations of SLCO2A1 gene. Conventional treatment of inflammatory bowel disease and COX-2 inhibitors were ineffective. Conclusions: CEAS is an autosomal recessive genetic disease which widely involves the gastrointestinal tract, and can be associated with skin and bone involvement. There is no effective treatment for CEAS at present. CEAS is a different entity from other inflammatory gastrointestinal diseases.

Metabolomics Insights in Early Childhood Caries

Dental caries is characterized by a dysbiotic shift at the biofilm-tooth surface interface, yet comprehensive biochemical characterizations of the biofilm are scant. We used metabolomics to identify biochemical features of the supragingival biofilm associated with early childhood caries (ECC) prevalence and severity. The study's analytical sample comprised 289 children ages 3 to 5 (51% with ECC) who attended public preschools in North Carolina and were enrolled in a community-based cross-sectional study of early childhood oral health. Clinical examinations were conducted by calibrated examiners in community locations using International Caries Detection and Classification System (ICDAS) criteria. Supragingival plaque collected from the facial/buccal surfaces of all primary teeth in the upper-left quadrant was analyzed using ultra-performance liquid chromatography-tandem mass spectrometry. Associations between individual metabolites and 18 clinical traits (based on different ECC definitions and sets of tooth surfaces) were quantified using Brownian distance correlations (dCor) and linear regression modeling of log₂-transformed values, applying a false discovery rate multiple testing correction. A tree-based pipeline optimization tool (TPOT)-machine learning process was used to identify the best-fitting ECC classification metabolite model. There were 503 named metabolites identified, including microbial, host, and exogenous biochemicals. Most significant ECC-metabolite associations were positive (i.e., upregulations/enrichments). The localized ECC case definition (ICDAS ≥1 caries experience within the surfaces from which plaque was collected) had the strongest correlation with the metabolome (dCor P = 8 × 10^-3). Sixteen metabolites were significantly associated with ECC after multiple testing correction, including fucose (P = 3.0 × 10^-6) and N-acetylneuraminate (p = 6.8 × 10^-6) with higher ECC prevalence, as well as catechin (P = 4.7 × 10^-6) and epicatechin (P = 2.9 × 10^-6) with lower. Catechin, epicatechin, imidazole propionate, fucose, 9,10-DiHOME, and N-acetylneuraminate were among the top 15 metabolites in terms of ECC classification importance in the automated TPOT model. These supragingival biofilm metabolite findings provide novel insights in ECC biology and can serve as the basis for the development of measures of disease activity or risk assessment.

[Contagiousness and secondary attack rate of 2019 novel coronavirus based on cluster epidemics of COVID-19 in Guangzhou]

Objective: To analyze the contagiousness and secondary attack rate of 2019 novel coronavirus in cluster epidemics in Guangzhou and provide evidence for the prevention and control of COVID-19. Methods: All the individuals identified to be infected with 2019-nCoV in Guangzhou, including confirmed cases and asymptomatic cases, were included and classified as imported cases and local cases. The first case of each cluster epidemic was defined as index case, and the number of subsequent infections was calculated to evaluate the contagiousness and secondary attack rate of 2019 novel coronavirus in the shortest incubation period of 1-3 days. Results: As of 18 February, 2020, a total of 349 cases of 2019-nCoV infection, including 339 confirmed cases (97.13%) and 10 asymptomatic cases (2.87%) were reported in Guangzhou. There were 68 clusters involving 217 2019-nCoV infection cases (210 confirmed cases and 7 asymptomatic cases). The median number of subsequent infections caused by an index case in a cluster epidemic was 3, among which 2 were confirmed cases and 1 was asymptomatic cases, respectively. The average number of contagiousness was 2.18 in shorted incubation period of 1-3 days (The average number of infected cases were 2.18 cases by the index case in a cluster epidemic), the average infection number in family members was 1.86, and the infection ratio of family member transmission was 85.32% (1.86/2.18). The secondary attack rate in close contacts with shortest incubation period of 1-3 days was 17.12%-18.99%, the secondary attack rate in family members was 46.11%-49.56%. Conclusions: The cluster epidemic of COVID-19 in Guangzhou mainly occurred in families, the contagiousness was high. It is necessary to strengthen the prevention and control to reduce the community transmission of COVID-19.

[Effect of HIF-1α and BRD4 on autophagy level of breast cancer cell in hypoxic microenvironment]

Objective: To investigate the expressions of HIF-1α, BRD4, Beclin1, LC3B and p62 in breast cancer tissues and their clinicopathological significance, and to study alterations of their expression in breast cancer cells under hypoxic microenvironment. Methods: Immunohistochemistry was used to detect HIF-1α, BRD4, Beclin1, LC3B and p62 protein expressions in 125 breast cancer tissues and 50 para-cancer normal breast tissues, and their correlation with clinicopathologic characteristics were analyzed. The expression of these proteins were also measured after 24 hours of hypoxia stimulation was detected in different breast cancer cell lines and normal breast epithelial cells. Results: The expression of HIF-1α, BRD4, Beclin1 and LC3B proteins in breast cancer tissues were significantly higher than in para-cancer normal breast tissues (P<0.05). There was a positive association between histologic grade, the expression of HIF-1α, BRD4, Beclin1 and LC3B (P<0.05). High expressions of HIF-1a and Beclin1 were often correlated with lymph node metastasis and lymphatic invasion (P<0.05). Increased HIF-1α, BRD4, Beclin1 and LC3B expression was associated with ER or PR negativity, but only HIF-1α was associated with HER2 positivity (P<0.05). HIF-1α, BRD4, Beclin1, and LC3B were positively correlated with each other in breast cancer tissues (P<0.01). After 24 hours of hypoxic stimulation, the expression of HIF-1α, BRD4, Beclin1 and LC3B was up-regulated in breast cancer cells. Conclusions: Hypoxia induces autophagy in breast cancer tissues. HIF-1α is positively correlated with BRD4, suggesting that BRD4 is involved in the regulation of autophagy by hypoxic microenvironment in breast cancer. High expression of HIF-1α, BRD4 and autophagy may play an important role in the development of breast cancer.

Evaluation of an accelerated 3D modulated flip-angle technique in refocused imaging with an extended echo-train sequence with compressed sensing for imaging of the knee: comparison with routine 2D MRI sequences

AIM

To accelerate the acquisition of high-resolution magnetic resonance imaging (MRI) by using the three-dimensional (3D) matrix sequence with compressed sensing and to compare it with conventional two-dimensional (2D) proton-density (PD) and fast spin-echo (FSE) sequences.

MATERIALS AND METHODS

3D matrix, 2D FSE, and PD sequences were acquired from 68 participants using 3 T magnetic resonance imaging (MRI). Two radiologists scored image quality independently on a four-point scale. The structural similarity index (SSIM), and signal- (SNRs) and contrast-to-noise ratios (CNRs) of different anatomical structures of the knee were assessed and compared between sequences using Wilcoxon signed-rank tests and Cohen's kappa.

RESULTS

The median acquisition time reduction was 44.5%. There was a substantial to perfect agreement for the rating between the 3D matrix FSE and 2D FSE or PD sequences when evaluating cartilage, subchondral bone, and ligaments (κ=0.783-872, p>0.05). The mean SSIM values between the 3D matrix FSE and 2D FSE, and between the 3D matrix PD and 2D PD sequences was 0.994 and 0.971, respectively, which are acceptable. No significant differences were found in SNR between the 3D matrix FSE and 2D FSE, and between the 3D matrix PD and 2D PD sequences, even though the SNR appeared to be higher on routine 2D sequences. The CNR of subchondral bone-meniscus, subchondral bone-joint fluid, and meniscus-joint fluid did not differentiate significantly between the 3D matrix sequence and routine 2D sequences.

CONCLUSIONS

3D matrix reduced the acquisition time in routine clinical knee MRI without the loss in image quality, SNR, and CNR.

Double-cone ignition scheme for inertial confinement fusion

While major progress has been made in the research of inertial confinement fusion, significant challenges remain in the pursuit of ignition. To tackle the challenges, we propose a double-cone ignition (DCI) scheme, in which two head-on gold cones are used to confine deuterium-tritium (DT) shells imploded by high-power laser pulses. The scheme is composed of four progressive controllable processes: quasi-isentropic compression, acceleration, head-on collision and fast heating of the compressed fuel. The quasi-isentropic compression is performed inside two head-on cones. At the later stage of the compression, the DT shells in the cones are accelerated to forward velocities of hundreds of km s^-1. The head-on collision of the compressed and accelerated fuels from the cone tips transfer the forward kinetic energy to the thermal energy of the colliding fuel with an increased density. The preheated high-density fuel can keep its status for a period of approximately 200 ps. Within this period, MeV electrons generated by ps heating laser pulses, guided by a ns laser-produced strong magnetic field further heat the fuel efficiently. Our simulations show that the implosion inside the head-on cones can greatly mitigate the energy requirement for compression; the collision can preheat the compressed fuel of approximately 300 g cm^-3 to a temperature above keV. The fuel can then reach an ignition temperature of greater than 5 keV with magnetically assisted heating of MeV electrons generated by the heating laser pulses. Experimental campaigns to demonstrate the scheme have already begun. This article is part of a discussion meeting issue 'Prospects for high gain inertial fusion energy (part 1)'.