Association of clinical factors and recent anticancer therapy with COVID-19 severity among patients with cancer: a report from the COVID-19 and Cancer Consortium

BACKGROUND

Patients with cancer may be at high risk of adverse outcomes from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We analyzed a cohort of patients with cancer and coronavirus 2019 (COVID-19) reported to the COVID-19 and Cancer Consortium (CCC19) to identify prognostic clinical factors, including laboratory measurements and anticancer therapies.

PATIENTS AND METHODS

Patients with active or historical cancer and a laboratory-confirmed SARS-CoV-2 diagnosis recorded between 17 March and 18 November 2020 were included. The primary outcome was COVID-19 severity measured on an ordinal scale (uncomplicated, hospitalized, admitted to intensive care unit, mechanically ventilated, died within 30 days). Multivariable regression models included demographics, cancer status, anticancer therapy and timing, COVID-19-directed therapies, and laboratory measurements (among hospitalized patients).

RESULTS

A total of 4966 patients were included (median age 66 years, 51% female, 50% non-Hispanic white); 2872 (58%) were hospitalized and 695 (14%) died; 61% had cancer that was present, diagnosed, or treated within the year prior to COVID-19 diagnosis. Older age, male sex, obesity, cardiovascular and pulmonary comorbidities, renal disease, diabetes mellitus, non-Hispanic black race, Hispanic ethnicity, worse Eastern Cooperative Oncology Group performance status, recent cytotoxic chemotherapy, and hematologic malignancy were associated with higher COVID-19 severity. Among hospitalized patients, low or high absolute lymphocyte count; high absolute neutrophil count; low platelet count; abnormal creatinine; troponin; lactate dehydrogenase; and C-reactive protein were associated with higher COVID-19 severity. Patients diagnosed early in the COVID-19 pandemic (January-April 2020) had worse outcomes than those diagnosed later. Specific anticancer therapies (e.g. R-CHOP, platinum combined with etoposide, and DNA methyltransferase inhibitors) were associated with high 30-day all-cause mortality.

CONCLUSIONS

Clinical factors (e.g. older age, hematological malignancy, recent chemotherapy) and laboratory measurements were associated with poor outcomes among patients with cancer and COVID-19. Although further studies are needed, caution may be required in utilizing particular anticancer therapies.

CLINICAL TRIAL IDENTIFIER

NCT04354701.

POS0775 APLS-ASSOCIATED RETINAL VASCULOPATHY AS A PRESENTATION OF THROMBOTIC MICROANGIOPATHY

Background:

Persistent antiphospholipid antibodies (aPL) positivity was a recognized risk factor for thrombotic events, obstetric morbidity and a variety of manifestations beyond thrombosis. The presence of some non-criteria manifestations including thrombocytopenia, hemolytic anemia, and APS nephropathy should prompt consideration for thrombotic microangiopathy (TMA).1 Patients with APS can also present with a variety of ocular and neuro-ophthalmic manifestations, such as retinal artery/vein occlusion, retinal arteritis, optic neuritis and ischemic optic neuropathy, with underlying mechanisms remained elusive. Retinal vasculopathy including retinal artery occlusion (RAO) or retinal vein occlusion (RVO) was recently found occurred more frequently in APS patients with thrombocytopenia2, suggested other possible mechanisms besides thromboembolism.

Objectives:

To explore risk factors and possible mechanisms of retinal vasculopathy among APS patients.

Methods:

In this single-center case-control study among APS patients, we evaluated patients who fulfilled 2006 Sapporo APS Classification Criteria3 with or without retinal vasculopathy during 2018-2020 at Peking Union Medical College Hospital. Demographic data, aPL-related manifestations, cardiovascular risk factors and antibodies profile were compared and a logistical regression model was built. Hierarchical cluster analysis with the Euclidean distance and the Ward method was applied to identify clusters of variables.

Results:

A total of 310 APS patients (67.4% female, mean age 38.1 years) were included, of whom 18 patients were diagnosed with retinal vasculopathy (9 with RVO and 9 with RAO). No significant differences was found among most demographic characteristics, clinical manifestations, or antibody profile. However, APS-related heart valve disease (OR 13.66, 95% confidence interval [CI] 4.55-40.98), APS nephropathy (OR 12.77, 95% CI 4.04-40.35), thrombocytopenia (OR 2.63, 95% CI 1.01-6.89) and high serum IgM (OR 3.67, 95% CI 1.30-10.40) were predictive of retinal vasculopathy (Figure 1 A). APS-related heart valve disease and nephropathy were also found statistical significant in multivariate logistical regression (Figure 1 B). They and other non-criteria manfestations were aggregated with retinal vasculopathy from cluster analysis of variables (Figure 1 C).

Conclusion:

Patients with APS-related heart valve disease and nephropathy suffered a higher risk of retinal vasculopathy including RAO and RVO. The underlying mechanisms of aPLs-associated retinal vasculopathy may involve TMA, leading to a poor prognosis and therapeutic changes.

References:

[1]Kotzen ES, Roy S, Jain K. Antiphospholipid Syndrome Nephropathy and Other Thrombotic Microangiopathies Among Patients With Systemic Lupus Erythematosus. Adv Chronic Kidney Dis. 2019 Sep;26(5):376-386.

[2]Ermakova NA, Alekberova ZS, Reshetniak TM, Kalashnikova LA, Kosheleva NM. [Retinal vascular lesions in systemic lupus erythematosus and secondary antiphospholipid syndrome]. Vestn Oftalmol. 2005 Sep-Oct;121(5):31-6.

[3]Miyakis S, Lockshin MD, Atsumi T, Branch DW, Brey RL, Cervera R, et al. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS). J Thromb Haemost. 2006 Feb;4(2):295-306.

Figure 1. A) Forest plot of univariate analysis; B) Forest plot of multivariate logistic regression; C) Cluster analysis of variables.

Disclosure of Interests:

None declared

POS0186 METABOLOMIC SIGNATURES FOR KNEE CARTILAGE VOLUME LOSS OVER 10 YEARS

Background:

Osteoarthritis (OA) is the most common form of arthritis, and its impact is increasing year by year due to an aging population and lack of effective treatments. One of the main structural pathological changes of OA is the loss of articular cartilage. Tools that can predict cartilage loss would help identify people at high risk, thus preventing OA development.

Objectives:

Using a metabolomics approach, the current study aimed to identify serum metabolomic signatures for predicting the loss of knee cartilage volume over 10 years in a well-established community-based cohort - the Tasmania Older Adult Cohort (TASOAC).

Methods:

TASOAC is an on-going, prospective, population-based study of older adults who were randomly selected from the roll of electors in Southern Tasmania, Australia. Participants had a right knee magnetic resonance imaging (MRI) scan at baseline and a 10-year follow-up. Cartilage volume was measured in the medial, lateral, and patellar compartments and change in cartilage volume over 10 years was calculated as percentage change per year. Fasting serum samples collected at 2.6-year follow-up were metabolomically profiled using the TMIC Prime Metabolomics Profiling Assay which measures a total of 143 metabolites. 129 metabolite concentrations passed the quality control and the pairwise ratios of them as the proxies of enzymatic reaction were calculated. Linear regression models were used to test the association between each of the metabolite ratios and change in cartilage volume in each of the knee compartments with adjustment for age, sex, and body mass index (BMI). The significance was defined at a=3.0×10-6 to control multiple testing of 16,512 ratios with Bonferroni method.

Results:

A total of 344 participants (51% females) were included. The mean baseline age was 62.83±6.13 years and the mean BMI was 27.48±4.41 kg/m2. The average follow-up time was 10.84±0.66 years. Cartilage volume reduced by 1.34±0.72%, 1.06±0.58%, and 0.98±0.46% per year in the medial, lateral, and patellar compartments, respectively. Our data showed that an increased ratio of hexadecenoylcarnitine (C16:1) to tetradecanoylcarnitine (C14) was associated with a 0.12±0.02% per year reduction in patellar cartilage volume (p = 8.80×10-7). An increased ratio of hexadecenoylcarnitine (C16:1) to dodecanoylcarnitine (C12) was also associated with a 0.12±0.02% per year reduction in patellar cartilage volume (p = 2.66×10-6). While there were several metabolite ratios associated with cartilage volume loss in the medial and lateral compartments, none of them reached the predefined significance level.

Conclusion:

Our data suggested that alteration of fatty acid β-oxidation is involved in knee cartilage loss, especially in the patellar compartment, and the serum ratio of C16:1 to C14 and to C12 could be used to predict long-term patellar cartilage loss.

Acknowledgements:

We thank all the study participants who made the study possible. The original TASOAC study was supported by the National Health and Medical Research Council (NHMRC) and the current study was supported by the Canadian Institutes of Health Research (CIHR).

Disclosure of Interests:

None declared

Setting the new FRAX reference threshold without bone mineral density in Chinese postmenopausal women

PURPOSE

Despite the large number of osteoporosis patients in China, the diagnosis and treatment rates remain low. The Fracture Risk Assessment Tool (FRAX) can be used to effectively evaluate fracture risk. In this study, we explored the Chinese-specific thresholds of FRAX without the T-score.

METHODS

In all, 264 postmenopausal women aged > 50 years were randomly recruited from community-medical centers. All subjects completed self-reported questionnaires, BMD measurements, and spinal radiographs. The 10-year hip and major osteoporotic fracture risks were calculated by FRAX. A new threshold for both 10-year hip and major osteoporotic fracture risk was explored with receiver operating characteristic (ROC) curve analysis.

RESULTS

Overall, 92 subjects were diagnosed with osteoporosis. Among them, 14 participants with T-score > - 2.5 were diagnosed with osteoporosis based on clinical fractures. ROC analysis showed the cut-off value of the 10-year hip osteoporotic fracture for detecting osteoporosis was 0.95%, while that of 10-year major osteoporotic fracture was 4.95%. The sensitivity and specificity of the 10-year hip osteoporotic fracture probability for detecting osteoporosis were 0.86 and 0.59, respectively, while the guideline-recommended threshold had a sensitivity of 0.49 and specificity of 0.83. The sensitivity and specificity of the 10-year major osteoporotic fractures with the new threshold were 0.76 and 0.69, respectively, while the recommended threshold had a sensitivity of 0 and specificity of 1.

CONCLUSION

Current guideline-recommended FRAX thresholds without BMD showed low sensitivity. Therefore, 10-year osteoporotic hip fracture probability ≥ 0.95% and 10-year osteoporotic major fracture probability ≥ 4.95% are recommended as the new thresholds.

Krüppel-like factor 6 promotes odontoblastic differentiation through regulating the expression of dentine sialophosphoprotein and dentine matrix protein 1 genes

AIM

To investigate the potential role of Krüppel-like factor 6 (KLF6) in the odontoblastic differentiation of immortalized dental papilla mesenchymal cells (iMDP-3) cells.

METHODOLOGY

Alizarin Red S (ARS) and Alkaline phosphatase (ALP) staining was used to examine the mineralization effect of iMDP-3 cells after odontoblastic induction. Real-time PCR and Western blotting were employed to analyse dentine sialophosphoprotein (DSPP), dentine matrix protein 1 (DMP1), RUNX family transcription factor 2 (RUNX2), ALP and KLF6 expression during this process. Co-expression of the KLF6 with DMP1, DSPP and RUNX2 was detected by double immunofluorescence staining to explore their local relationship in the cell. To further investigate KLF6 functions, Klf6 gain- and loss-of-function assays followed by ARS and ALP stainings, real-time PCR and Western blotting were performed using Klf6-overexpression plasmids and Klf6 siRNA to investigate whether changes in Klf6 expression affect the odontoblastic differentiation of iMDP-3 cells. Dual-luciferase reporter assays were used to elucidate the mechanistic regulation of Dspp and Dmp1 expression by Klf6. Means were compared using the unpaired t-test and Kruskal-Wallis one-way anova with P < 0.05 and P < 0.01 defined as statistical significance levels.

RESULTS

The expression levels of Klf6 (P < 0.01), Dspp (P < 0.05), Dmp1 (P < 0.01), Runx2 (P < 0.01) and Alp (P < 0.01) were significantly elevated during odontoblastic differentiation of iMDP-3 cells. KLF6 was co-localized with DSPP, DMP1 and RUNX2 in the cytoplasm and nucleus of iMDP-3 cells. Overexpression of Klf6 promoted the odontoblastic differentiation of iMDP-3, whereas the inhibition of Klf6 prevented this procession. Dual-luciferase assays revealed that Klf6 upregulates Dspp and Dmp1 transcription in iMDP-3 cells during odontoblastic differentiation.

CONCLUSION

Klf6 promoted odontoblastic differentiation by targeting the transcription promoter of Dmp1 and Dspp. This study may offer novel insights into strategies for treating injuries to dental pulp tissue.

Cellular viability and death biomarkers enables the evaluation of ocular irritation using the bovine corneal opacity and permeability assay

The BCOP assay is used in the identification of chemicals that cause no ocular irritation or serious damage. However, this method has not been found to adequately discriminate between mild from moderate ocular irritation (category 2A/2B), based upon the animal data. In this study, we aimed to establish methods for discerning ocular irritation by chemicals. We used the BCOP assay and the fluorescence staining methods based on biomarkers for cellular viability and death. The potential for ocular irritation by 12 chemicals from different UN GHS categories was assessed by the BCOP assay. Cryosections of bovine corneas were obtained. The necrotic nucleus was TUNEL labeled, cytoplasmic f-actin was stained by phalloidin while the nucleus was stained by DAPI. The depth of injury (DOI) was then measured. According to BCOP assay, in vivo data of Draize eye test and DOI, the results showed that category NC irritants caused ≤ 10 % epithelial DOI, irritants of category 2B caused >10 % epithelial DOI and showed no stromal damage, while category 2A showed damage to the stroma. Based on these results, the GHS prediction model could distinguish between GHS 2A and 2B. Authenticating the viability of BCOP by DOI measurements can provide a more reliable basis for classifying ocular irritants.

The comparative evaluation of transcrestal and lateral sinus floor elevation in sites with residual bone height ≤6 mm: A two-year prospective randomized study

OBJECTIVES

To compare clinical and radiographic outcomes between transcrestal sinus floor elevation (TSFE) and lateral sinus floor elevation (LSFE) approaches of simultaneous implant placement in atrophic maxilla.

MATERIALS AND METHODS

Patients with a residual bone height (RBH) ≤6 mm were enrolled and randomly assigned to TSFE and LSFE groups. Patients in both groups simultaneously underwent sinus floor elevation with bovine-derived xenograft and implant placement. Clinical and radiographic results were evaluated immediately after surgery and after 6, 12, 18, and 24 months. The endo-sinus bone gain (ESBG), apical implant bone height (ABH), endo-sinus bone-implant contact rate (EBICR), and crestal bone level (CBL) were assessed using panoramic radiographs.

RESULTS

Forty-one implants (TSFE: 21, LSFE: 20) were placed in cases with a mean RBH of 3.77 ± 1.16 mm. All implants obtained clinical success and satisfactory ESBG at 24 months. No significant differences were found in ESBG and ABH between two groups immediately after surgery, but LSFE group showed significantly higher values than TSFE group thereafter. Grafts in TSFE group reached stability 6 months earlier than that in LSFE group. In both groups, EBICR was almost 100%, and CBL showed no detectable changes.

CONCLUSIONS

LSFE can achieve higher ESBG 2 years after surgery. Otherwise, TSFE could be an alternative to LSFE, when the access for lateral window preparation is limited. Both approaches were highly predictable for RBH ≤6 mm during 24-month observation period for the implants placed simultaneously.

Stem-cell-derived ECM sheet-implant complexes for enhancing osseointegration

Numerous treatment methods have been developed to modify the surface of dental implants to improve cell migration and proliferation, removal torque, and osseointegration. Recent studies have constructed cell sheet-implant complexes with enhanced osteogenic capabilities. However, these complexes have some limitations, such as requirements for complex preparation processes, cell vitality maintenance, strict preservation conditions, and the induction of immunogenicity. Extracellular matrix (ECM) sheets without cells may be a more desirable material. To date, the effect of ECM sheets on implant osseointegration has not been reported. In this study, we fabricated ECM sheet-implant complexes through the combination of rat bone marrow mesenchymal stem cell (BMSC)-derived ECM sheets with sandblasted, large-grit, acid-etched (SLA) implants. These complexes were characterized by light microscopy, scanning electron microscopy (SEM), and immunofluorescence (IF) assays. The adhesion, proliferation, and osteogenic differentiation of BMSCs cultured on ECM sheets were detected in vitro. Then, the ECM sheet-implant complexes were transplanted into the metaphysis of the tibias of rats to evaluate the implant osseointegration in vivo. The results showed that ECM sheets were successfully constructed and showed significantly improved adhesion and proliferation. BMSCs cultured on ECM sheets upregulated the expression levels of the osteogenic-related genes alkaline phosphatase (ALP), bone morphogenetic protein 2 (BMP2), and runt-related transcription factor 2 (Runx2) compared to controls. In vivo, ECM sheet-implant complexes demonstrated superior new bone formation. Our findings proved that the BMSC-derived ECM sheets promoted osseointegration in vitro and in vivo. The current study indicated that the ECM sheet could be an ideal tissue engineering material, and ECM sheet-implant complexes could provide a strategy with low immunogenicity and easy storage and transportation. This research provides a novel strategy for the development of implant surface modification approaches.

Exosomes Enhance Adhesion and Osteogenic Differentiation of Initial Bone Marrow Stem Cells on Titanium Surfaces

Successful osseointegration involves the biological behavior of bone marrow stem cells (BMSCs) on an implant surface; however, the role of BMSC-derived extracellular vesicles (EVs)/exosomes in osseointegration is little known. This study aimed to: (i) explore the interaction force between exosomes (Exo) and cells on a titanium surface; (ii) discuss whether the morphology and biological behavior of BMSCs are affected by exosomes; and (iii) preliminarily investigate the mechanism by which exosomes regulate cells on Ti surface. Exosomes secreted by rat BMSCs were collected by ultracentrifugation and analyzed using transmission electron microscopy and nanoparticle tracking analysis. Confocal fluorescence microscopy, scanning electron microscopy, Cell Counting Kit-8 (CCK-8), quantitative real-time polymerase chain reaction techniques, and alkaline phosphatase bioactivity, Alizarin Red staining, and quantification were used to investigate the exosomes that adhere to the Ti plates under different treatments as well as the morphological change, adhesion, spread, and differentiation of BMSCs. We found that exosomes were efficiently internalized and could regulate cell morphology and promoted the adhesion, spreading, and osteogenic differentiation of BMSCs. These were achieved partly by activating the RhoA/ROCK signaling pathway. Our discovery presents a new insight into the positive regulatory effect of exosomes on the biological behaviors of BMSCs on Ti surface and provides a novel route to modify the surface of a Ti implant.

Displacement and stress distribution of the maxilla under different surgical conditions in three typical models with bone-borne distraction: a three-dimensional finite element analysis

OBJECTIVE

The present study compared the skeletal effects of surgically assisted rapid maxillary expansion (SARME) with different surgeries in three representative finite element (FE) models.

STUDY DESIGN

According to the ossification level of midpalatal suture, three FE models, with different elasticity moduli of sutures (E = 1 MPa, 500 MPa, and 13,700 MPa) were constructed, to represent three age groups of patients. Within each model, four groups were set up according to different surgeries: group I (control group without surgery), II (paramedian osteotomy), III (pterygomaxillary separation), and IV (paramedian osteotomy and pterygomaxillary separation). An expansion force of 100 N and 1 mm displacement were applied via a bone-borne distraction to simulate the expansion process.

RESULTS

By analyzing these models, the maximum displacement of maxilla was observed in group IV, with E = 1 MPa model exhibiting the most displacement (28.5 × 10^-6 mm), followed by group II (21.4 × 10^-6 mm). Group IV showed a unique backward-downward rotation with minimum stress distributions in three models (9 MPa, 131 MPa, and 140 MPa, respectively), and group II exhibited comparable low stress distributions (12 MPa, 151 MPa, and 230 MPa, respectively). Lowest stress was found in E = 1 MPa model, compared with the other two models.

CONCLUSION

There is no need to perform surgeries when the midpalatal suture is open, and surgery guidelines are the same for partial and complete fusion sutures. Furthermore, exclusive use of partial paramedian osteotomy is sufficient enough to reduce stress and expand the posterior part of maxilla, and it is less invasive.

Mitochondrial ribosomal protein S9M is involved in male gametogenesis and seed development in Arabidopsis

Mitochondrial function is critical for cell vitality in all eukaryotes including plants. Although plant mitochondria contain many proteins, few have been studied in the context of plant development and physiology. We used knock-down mutant RPS9M to study its important role in male gametogenesis and seed development in Arabidopsis thaliana. Knock-down of RPS9M in the rps9m-3 mutant led to abnormal pollen development and impaired pollen tube growth. In addition, both embryo and endosperm development were affected. Phenotype analysis revealed that the rps9m-3 mutant contained a lower amount of endosperm and nuclear proteins, and both embryo cell division and embryo pattern were affected, resulting in an abnormal and defective embryo. Lowering the level of RPS9M in rps9m-3 affects mitochondrial ribosome biogenesis, energy metabolism and production of ROS. Our data revealed that RPS9M plays important roles in normal gametophyte development and seed formation, possibly by sustaining mitochondrial function.

[COVID-19 pandemic: global epidemiological trends and China's subsequent preparedness and responses]

The outbreak of COVID-19 has spread quickly across 114 countries/territories/areas in six continents worldwide and has been announced as a pandemic by WHO. This study analyzed global COVID-19 epidemiological trends, examined impact of the pandemic on global health security, diplomacy, and social environment in China, and provided short- and long-term strategic policy recommendations for China's subsequent preparedness and responses.

[Main non-state actors and progress of actions in global malaria elimination programme: a review]

With the joint efforts of countries and global non-state actors, great achievements have been made in the global malaria control programme; however, malaria remains a serious threat to human health. As the global leader for combating malaria, WHO formulated The Global Technical Strategy for Malaria 2016-2030, and the Global Malaria Programme, under the leadership of WHO, is responsible for implementing 5 key projects to achieve the goal proposed in The Global Technical Strategy for Malaria 2016-2030. In addition, the Global Fund, the U.S. President's Malaria Initiative and Bill & Melinda Gates Foundation also play an important role in global malaria elimination programme. This review describes the currently main non-state actors participating in the global malaria elimination programme, and calls for the enhanced inter-actor coordination and close collaboration with state governments to achieve the great goal of malaria elimination in the world.

CT characteristics of patients infected with 2019 novel coronavirus: association with clinical type

AIM

To summarise the features of chest computed tomography (CT) of a series of patients infected with 2019 novel coronavirus (2019-nCov) to speed up recognition and have a better understanding of COVID-19 disease.

MATERIALS AND METHODS

The clinical information and chest CT images of 93 patients infected with 2019-nCov from multiple centres were reviewed.

RESULTS

Of the 93 cases, abnormalities in 91 cases were located at the subpleural level, presenting with ground-glass opacity (GGO; n=69, 74.2%) and consolidation (n=56, 60.2%) in multiple lobes. Other CT features included vascular dilatation (n=83, 89.2%), interlobular septal thickening (n=29, 31.2%), bronchodilatation (n=44, 47.3%), the crazy-paving sign (n=34, 36.6%), the sieve-hole sign (n=12, 12.9%), pleural thickening (n=21, 22.6%), and pleural effusion (n=8, 8.6%). Multiple lobe involvement, including the presence of consolidation, the crazy-paving sign, interlobular septal thickening, pleural thickening and pleural effusion, was more common in critical patients with heavy/critical infection (p<0.05), whereas the presence of GGO, involvement of one or two lobes, and the halo sign were more common in patients with mild/common-type infections (p<0.05). Moreover, older age, higher body temperature, complaints of chest tightness and breathlessness, and lymphopenia was associated with heavy/critical infections.

CONCLUSION

The CT and clinical appearances of COVID-19 are variable and reflect the severity of COVID-19 to some extent.

Single-site laparoscopic percutaneous extraperitoneal closure (SLPEC) of hernia sac high ligation using an ordinary taper needle: a novel technique for pediatric inguinal hernia

PURPOSE

Laparoscopic high ligation of the internal inguinal ring is an alternative procedure for treatment of pediatric inguinal hernia (PIH), with a major trend toward increasing use of extracorporeal knotting and decreasing use of working ports. We have utilized this laparoscopic technique to treat the entire spectrum of PIH (including incarcerated cases) for more than 17 years, and the technique continues to evolve and improve. We herein report our latest modification of this minimally invasive technique, namely single-site laparoscopic percutaneous extraperitoneal closure (SLPEC) of hernia sac high ligation using an ordinary taper needle, and evaluate its safety and efficacy.

METHODS

From July 2016 to July 2019, 790 children with indirect PIH were treated by laparoscopic surgery. All patients underwent high ligation surgery with a modified single-site laparoscopic technique mainly performed by extracorporeal suturing with an ordinary closed-eye taper needle (1/2 arc 11 × 34). The clinical data were retrospectively analyzed.

RESULTS

All surgeries were successful without serious complications. A contralateral patent processus vaginalis (CPPV) was found intraoperatively and subsequently repaired in 190 patients (25.4%). The mean operative time was 15 min (8-25 min) for 557 unilateral hernias and 21 min (14-36 min) for 233 bilateral hernias. The mean postoperative stay was 20 h. Minor complications occurred in five patients (0.63%) and were managed properly, with no major impact on the final outcomes. No recurrence was noted in the patients who were followed up for 6-42 months. No obvious scar was present postoperatively.

CONCLUSION

Modified SLPEC of hernia sac high ligation using an ordinary taper needle for repair of indirect PIH is a safe, reliable, and minimally invasive procedure with satisfactory outcome, with no special device being needed. It is easy to learn and perform and is worthy of popularization in the clinical setting.

Anisotropic Raman spectrum and transport properties of AuTe2Br flakes

Topological semimetal (TSM) AuTe₂Br thin flakes have been studied by Raman spectroscopy and magneto-transport measurement. The angle-resolved polarized Raman spectrum of AuTe₂Br (bulk and thin flake) shows strong anisotropy. Together with high resolution transmission electron microscopy (TEM), we establish a non-destructive method to determine the crystallographic orientation of AuTe₂Br flakes. At high temperature (T  >  50 K), the magneto-resistance (MR) of AuTe₂Br thin flakes shows typical parabolic-like behavior, which can be well fitted by the two-fluid model. However, at low temperature (T  ⩽  30 K), the MR of thin flakes (<17 nm) clearly deviates from the two-fluid model as well as from the Kohler's rule, suggesting a new type of scattering emerging below 30 K. Several possible scattering mechanisms are discussed and the respective corrections to MR are compared with our experimental data. In addition, the conductivity of these metallic crystals is also found to be highly anisotropic, with the hole mobility along the a axis about five times higher than that along the c axis.

Reliable Nonvolatile Memory Black Phosphorus Ferroelectric Field-Effect Transistors with van der Waals Buffer

Two-dimensional material-based ferroelectric field-effect transistors (2D-FeFETs) hold great promise in information storage and processing. However, an often-observed and hard-to-control anti-hysteresis response of 2D-FeFETs, for example, hysteretic switching of the resistance states of the devices opposite to that of the actual polarization of the ferroelectric dielectric, represents a major issue in the industrial applications of such devices. Here, we demonstrate a van der Waals buffer technique that eliminates anti-hysteresis in black phosphorus (BP) 2D-FeFETs and restores their intrinsic hysteretic behavior. Our modified BP 2D-FeFETs showed outstanding performance including high room-temperature carrier mobility, robust bistable states with fast response to a gate, a large on/off ratio at zero gate voltage, a large and considerably more stable memory window, and a long retention time. During repeated gate operation, the memory window of the buffered device is ∼7000 times more stable than the unbuffered device. Such a method could be crucial in future information technological applications that utilize the intrinsic properties of 2D-FeFETs.