Anomalous Hall Transport by Optically Injected Isospin Degree of Freedom in Dirac Semimetal Thin Film.

Chirality of massless fermions emerging in condensed matter is a key to understand their characteristic behavior as well as to exploit their functionality. However, the chiral nature of massless fermions in Dirac semimetals has remained elusive, due to equivalent occupation of carriers with the opposite chirality in thermal equilibrium. Here, we show that the isospin degree of freedom, which labels the chirality of massless carriers from a crystallographic point of view, can be injected by circularly polarized light. Terahertz Faraday rotation spectroscopy successfully detects the anomalous Hall conductivity by a light-induced isospin polarization in a three-dimensional Dirac semimetal, Cd3As2. Spectral analysis of the Hall conductivity reveals a long scattering time and a long decay time, which are characteristic of the isospin. The long-lived, robust, and reversible character of the isospin promises a potential application of Dirac semimetals in future information technology.

Simple Scoring System for Esophagogastric Varices Prediction in Hepatocellular Carcinoma Patients without Liver Stiffness Evaluation.

INTRODUCTION: For predicting esophagogastric varices (EGVs), the Virtual Baveno VII Consensus Workshop has proposed a combination of liver stiffness determination and platelet count measurement using a FibroScan®. However, FibroScan® is not available at all institutions. The present study aimed to develop a simple method to predict development of EGV using only general blood examination results. MATERIALS AND METHODS: A total of 1,090 hepatocellular carcinoma patients were enrolled, after excluding 956 with major portal vein tumor thrombus (Vp3/Vp4) or without upper gastrointestinal endoscopy examination results available. Those with EGV (≥ grade F2) or a history of treatment for the condition were defined as positive for significant EGV, and then clinical factors were retrospectively evaluated to determine indicators of occurrence. RESULTS: Logistic multivariate analysis showed platelet count (≤12 × 104/µL) (odds ratio [OR] 3.79, p < 0.001), mALBI grade 2a (OR 1.52, p = 0.036), and mALBI 2b or 3 (OR 3.46, p < 0.001) as significant predictive factors. Based on the OR values, platelet count (≤12 × 104/µL) and mALBI grade 2b/3 were each assigned 2 points and mALBI 2a was given 1 point, with the result termed recommendation for EGV screening (REGS) score. Significant EGV occurrence was noted in 2.9% (9/311) of the patients with a REGS score 0, 11.0% (13/118) with a score 1, 19.3% (53/274) with a score 2, 29.5% (39/132) with a score 3, and 38.0% (97/255) with a score 4 (p < 0.001). CONCLUSION: The findings indicate that REGS score can provide useful predictive information for development of significant EGV without the need for special equipment such as a FibroScan®.

Effects of entecavir and tenofovir alafenamide fumarate treatment on renal function in Japanese elderly patients with chronic hepatitis B.

AIM: Entecavir (ETV) and tenofovir alafenamide fumarate (TAF) are considered safe nucleoside/nucleotide analogs (NA) for the kidney. This study aimed to investigate the long-term effects of ETV or TAF on renal function in elderly patients with chronic hepatitis B (CHB) in Japan. METHODS: The study included 246 CHB patients treated with ETV (184 patients) or TAF (62 patients) for at least 2 years. These patients were divided into two groups: those <65 years of age (130 patients) and those ≥65 years of age (116 patients). The effects of the NAs on renal functions were examined by comparing the estimated glomerular filtration rates (eGFR) from baseline to 2 years between the two groups. RESULTS: The change in eGFR from baseline to 1 or 2 years after treatment was significantly decreased in both groups. However, the amount of change at 1 and 2 years was significantly greater in the group aged ≥65 years than in the group aged <65 years. The amount of change in eGFR from baseline to 1 and 2 years after treatment was significantly greater in the group aged ≥65 years than in the group aged <65 years, regardless of the type of NA, the prior treatment history, cirrhosis/chronic hepatitis, hypertension, dyslipidemia, and diabetes. Additionally, logistic regression analysis showed that age ≥65 years was independently associated with a decreased eGFR after 2 years of NA treatment. CONCLUSIONS: Long-term administration of NA to CHB patients over 65 years of age should be carefully monitored for renal impairment.

Changes in characteristics of gastroenterology center inpatients in Japan because of rapidly aging society.

BACKGROUND AND AIM: Rapidly aging societies have become a major issue worldwide including Japan. This study aimed to elucidate relative changes in the characteristics of inpatients in Japan related to this issue. METHODS: A total of 23 835 Japanese inpatients treated from 2010 to 2021 were enrolled (2010-2013, period I; 2014-2017, period II; 2018-2021, period III). Changes in clinical features were retrospectively analyzed based on ICD-10 diagnosis data. RESULTS: The percentage of patients aged over 75 years increased over time (period I, 38.0%; II, 39.5%, III, 41.4%). Emergency admissions comprised 27.5% of all in period I, which increased to 43.2% in period II and again to 44.5% in period III (P < 0.001). In period I, gastrointestinal disease, liver disease, pancreatic-biliary disease, and other disease types were noted in 47.4%, 29.5%, 19.2%, and 3.9%, respectively, while those values were 44.0%, 18.0%, 33.9%, and 4.1%, respectively, in period III (P < 0.001). The frequency of liver disease decreased by approximately 0.6-fold from periods I to III, while that of biliary-pancreatic disease increased by approximately 1.8-fold during that time. Both percentage and actual numbers of patients with biliary-pancreatic disease increased during the examined periods. Analysis of changes in the proportion of organs affected by malignancy during periods I, II, and III showed a marked increase in cases of biliary-pancreatic malignancy (11.6%, 19.5%, 26.6%, respectively) (P < 0.001). CONCLUSION: In association with the rapidly aging Japanese society, there has been an increasing frequency of biliary-pancreatic disease cases requiring hospitalization for treatment in the west Japan region of Shikoku.

ADAMTS-13: A Prognostic Biomarker for Portal Vein Thrombosis in Japanese Patients with Liver Cirrhosis.

Portal vein thrombosis (PVT), one of the most prevalent hepatic vascular conditions in patients with liver cirrhosis (LC), is associated with high mortality rates. An imbalance between a disintegrin-like metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS-13) enzyme and von Willebrand factor (VWF) is responsible for hypercoagulability, including spontaneous thrombus formation in blood vessels. Herein, we aimed to identify potential prognostic and diagnostic biomarkers in Japanese patients with LC and PVT. In total, 345 patients were divided into two groups: 40 patients who developed PVT (PVT group) and 305 who did not develop PVT (NPVT group). Among the 345 patients with LC, 81% (279/345) were deemed ineligible due to the presence of preventive comorbidities, active or recent malignancies, and organ dysfunction. The remaining 66 patients were divided into two groups: the PVT group (n = 33) and the NPVT group (n = 33). Plasma ADAMTS-13 activity (ADAMTS-13:AC) and the vWF antigen (VWF:Ag) were measured using enzyme-linked immunosorbent assays. Contrast-enhanced, three-dimensional helical computed tomography (CT) was used to detect and characterize PVT. ADAMTS-13:AC was significantly lower in the PVT group than in the NPVT group. No significant differences in plasma vWF:Ag or liver stiffness were observed between the two groups. ADAMTS-13:AC of <18.8 was an independent risk factor for PVT on multivariate analyses (odds ratio: 1.67, 95% confidence interval: 1.21-3.00, p < 0.002). The receiver operating characteristic analysis of ADAMTS-13:AC revealed an area under the curve of 0.913 in PVT detection. Patients with PVT having ADAMTS-13:AC ≥18.8 (n = 17) had higher albumin levels and better prognoses than those with ADAMTS-13:AC <18.8 (n = 16). No significant correlations of ADAMTS-13:AC levels with either fibrin degradation product or D-dimer levels were observed. ADAMTS-13:AC levels could be potential diagnostic and prognostic biomarkers for PVT in Japanese patients with LC.

Statins enhances antitumor effect of oxaliplatin in KRAS-mutated colorectal cancer cells and inhibits oxaliplatin-induced neuropathy.

BACKGROUND: KRAS mutations are fraught with the progression of colorectal cancer and resistance to chemotherapy. There are pathways such as extracellular regulated protein kinase 1/2 (ERK1/2) and Akt downstream and farnesylation and geranylgeranylation upstream that are activated upon mutated KRAS. Previous studies have shown that statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, are effective to treat KRAS mutated colorectal cancer cells. Increased doses of oxaliplatin (L-OHP), a well-known alkylating chemotherapeutic drug, causes side effects such as peripheral neuropathy due to ERK1/2 activation in spinal cords. Hence, we examined the combinatorial therapeutic efficacy of statins and L-OHP to reduce colorectal cancer cell growth and abrogate neuropathy in mice. METHODS: Cell survival and confirmed apoptosis was assessed using WST-8 assay and Annexin V detection kit. Detection of phosphorylated and total proteins was analyzed the western blotting. Combined effect of simvastatin and L-OHP was examined the allograft mouse model and L-OHP-induced neuropathy was assessed using cold plate and von Frey filament test. RESULTS: In this study, we examined the effect of combining statins with L-OHP on induction of cell death in colorectal cancer cell lines and improvement of L-OHP-induced neuropathy in vivo. We demonstrated that combined administration with statins and L-OHP significantly induced apoptosis and elevated the sensitivity of KRAS-mutated colorectal cancer cells to L-OHP. In addition, simvastatin suppressed KRAS prenylation, thereby enhancing antitumor effect of L-OHP through downregulation of survivin, XIAP, Bcl-xL, and Bcl-2, and upregulation of p53 and PUMA via inhibition of nuclear factor of κB (NF-κB) and Akt activation, and induction of c-Jun N-terminal kinase (JNK) activation in KRAS-mutated colorectal cancer cells. Moreover, simvastatin enhanced the antitumor effects of L-OHP and suppressed L-OHP-induced neuropathy via ERK1/2 activation in vivo. CONCLUSION: Therefore, statins may be therapeutically useful as adjuvants to L-OHP in KRAS-mutated colorectal cancer and may also be useful in the treatment of L-OHP-induced neuropathy.

Predicting Objective Response of Pembrolizumab in Platinum-Refractory Urothelial Carcinoma Based on NLR Fluctuation and Liver Metastases.

BACKGROUND AND PURPOSE: It is well known that patients with objective response to pembrolizumab have a durable duration of response leading to favorable survival outcomes. We investigated the possibility of predicting the objective response with concise indicators obtained from daily clinical practice. Methods In our multi-institutional cohort, 220 platinum-refractory metastatic urothelial carcinomas (mUC) treated with pembrolizumab for at least six weeks with complete information of objective response were investigated. Results The median follow-up was 7.3 months, and 119 patients deceased during the follow-up. A multivariate logistic regression analysis exhibited two independent variables predicting the objective response, including the neutrophil-lymphocyte ratio (NLR) change at six weeks of treatment and liver metastasis. We proposed a risk group using these two indicators. Patients with no predictive indicators / one of those were assigned to favorable (42%) / intermittent (47%) risk groups. Patients with both indicators were assigned to poor risk (11%). Notably, the objective response rate was well delineated in 41%, 25%, and 0% for favorable, intermediate, and poor risk groups, respectively (p<0.001). Distinct overall survival (OS) between the risk groups was also confirmed with the median OS of 14.1, 11.7, and 4.2 months in favorable, intermediate, and poor risk groups, respectively. CONCLUSIONS: At the six weeks of the pembrolizumab treatment, our risk model predicts the objective response rate precisely. Notably, those classified as 'poor risk'-marked by liver metastasis and a heightened NLR-should be considered for alternative therapy with a different mode of action, highlighting a critical decision point in treatment optimization.

Ultrafast Dynamics of Intrinsic Anomalous Hall Effect in the Topological Antiferromagnet Mn_{3}Sn.

We investigate ultrafast dynamics of the anomalous Hall effect (AHE) in the topological antiferromagnet Mn_{3}Sn with sub-100 fs time resolution. Optical pulse excitations largely elevate the electron temperature up to 700 K, and terahertz probe pulses clearly resolve ultrafast suppression of the AHE before demagnetization. The result is well reproduced by microscopic calculation of the intrinsic Berry-curvature mechanism while the extrinsic contribution is clearly excluded. Our work opens a new avenue for the study of nonequilibrium AHE to identify the microscopic origin by drastic control of the electron temperature by light.

Disentangling the Competing Mechanisms of Light-Induced Anomalous Hall Conductivity in Three-Dimensional Dirac Semimetal.

We experimentally elucidate the origin of the anomalous Hall conductivity in a three-dimensional Dirac semimetal, Cd_{3}As_{2}, driven by circularly polarized light. Using time-resolved terahertz Faraday rotation spectroscopy, we determine the transient Hall conductivity spectrum with special attention to its sign. Our results clearly show the dominance of direct photocurrent generation assisted by the terahertz electric field. The contribution from the Floquet-Weyl nodes is found to be minor when the driving light is in resonance with interband transitions. We develop a generally applicable classification of microscopic mechanisms of light-induced anomalous Hall conductivity.

Semiconducting Electronic Structure of the Ferromagnetic Spinel HgCr_{2}Se_{4} Revealed by Soft-X-Ray Angle-Resolved Photoemission Spectroscopy.

We study the electronic structure of the ferromagnetic spinel HgCr_{2}Se_{4} by soft-x-ray angle-resolved photoemission spectroscopy (SX-ARPES) and first-principles calculations. While a theoretical study has predicted that this material is a magnetic Weyl semimetal, SX-ARPES measurements give direct evidence for a semiconducting state in the ferromagnetic phase. Band calculations based on the density functional theory with hybrid functionals reproduce the experimentally determined band gap value, and the calculated band dispersion matches well with ARPES experiments. We conclude that the theoretical prediction of a Weyl semimetal state in HgCr_{2}Se_{4} underestimates the band gap, and this material is a ferromagnetic semiconductor.

Feasibility of Bone Mineral Density and Bone Microarchitecture Assessment Using Deep Learning With a Convolutional Neural Network.

OBJECTIVES: We evaluated the feasibility of using deep learning with a convolutional neural network for predicting bone mineral density (BMD) and bone microarchitecture from conventional computed tomography (CT) images acquired by multivendor scanners. METHODS: We enrolled 402 patients who underwent noncontrast CT examinations, including L1-L4 vertebrae, and dual-energy x-ray absorptiometry (DXA) examination. Among these, 280 patients (3360 sagittal vertebral images), 70 patients (280 sagittal vertebral images), and 52 patients (208 sagittal vertebral images) were assigned to the training data set for deep learning model development, the validation, and the test data set, respectively. Bone mineral density and the trabecular bone score (TBS), an index of bone microarchitecture, were assessed by DXA. BMDDL and TBSDL were predicted by deep learning with a convolutional neural network (ResNet50). Pearson correlation tests assessed the correlation between BMDDL and BMD, and TBSDL and TBS. The diagnostic performance of BMDDL for osteopenia/osteoporosis and that of TBSDL for bone microarchitecture impairment were evaluated using receiver operating characteristic curve analysis. RESULTS: BMDDL and BMD correlated strongly (r = 0.81, P < 0.01), whereas TBSDL and TBS correlated moderately (r = 0.54, P < 0.01). The sensitivity and specificity of BMDDL for identifying osteopenia or osteoporosis were 93% and 90%, and 100% and 94%, respectively. The sensitivity and specificity of TBSDL for identifying patients with bone microarchitecture impairment were 73% for all values. CONCLUSIONS: The BMDDL and TBSDL derived from conventional CT images could identify patients who should undergo DXA, which could be a gatekeeper tool for detecting latent osteoporosis/osteopenia or bone microarchitecture impairment.

Tracking Ultrafast Change of Multiterahertz Broadband Response Functions in a Photoexcited Dirac Semimetal Cd3As2 Thin Film.

The electromagnetic response of Dirac semimetals in the infrared and terahertz frequency ranges is attracting growing interest for potential applications in optoelectronics and nonlinear optics. The interplay between the free-carrier response and interband transitions in the gapless, linear dispersion relation plays a key role in enabling novel functionalities. Here we investigate ultrafast dynamics in thin films of a photoexcited Dirac semimetal Cd3As2 by probing the broadband response functions as complex quantities in the multiterahertz region (10-45 THz, 40-180 meV, or 7-30 µm), which covers the crossover between the inter- and intraband response. We resolve dynamics of the photoexcited nonthermal electrons, which merge with originally existing carriers to form a single thermalized electron gas and how it is facilitated by high-density excitation. We also demonstrate that a large reduction of the refractive index by 80% dominates the nonequilibrium infrared response, which can be utilized for designing ultrafast switches in active optoelectronics.

Stimulated Rayleigh Scattering Enhanced by a Longitudinal Plasma Mode in a Periodically Driven Dirac Semimetal Cd_{3}As_{2}.

Using broadband (12-45 THz) multi-terahertz spectroscopy, we show that stimulated Rayleigh scattering dominates the transient optical conductivity of cadmium arsenide, a Dirac semimetal, under an optical driving field at 30 THz. The characteristic dispersive line shape with net optical gain is accounted for by optical transitions between light-induced Floquet subbands, strikingly enhanced by the longitudinal plasma mode. Stimulated Rayleigh scattering with an unprecedentedly large refractive index change may pave the way for slow light generation in conductive solids at room temperature.

Percentage of overweight is overestimated in children of short stature.

BACKGROUND: The prevalence of overweight and obesity has increased, not just in adults but also in children. In Japan, the percentage of overweight (POW) is widely used for the estimation and assessment of percentage body fat (PBF) for children. We examine whether there is a difference between normal height and short stature children in terms of the relationship between POW and PBF. METHODS: A total of 321 children of normal height (163 boys, 158 girls) and 106 children with short stature (78 boys, 28 girls) were assessed according to sex. Percentage of overweight was used to represent the degree of obesity. The PBF of the total body was examined by dual energy X-ray absorptiometry. RESULTS: According to their PBF, normal height subjects of both sexes were classified as obese if they had a POW of more than 20%. However, short-stature subjects of both sexes were not classified as obese until the boys had a POW of 40%, and girls had a POW of 35%, respectively. Thus, overweight or obesity is overestimated in short stature children in both males and females with the rule "POW above 20% is recognized as obesity." CONCLUSIONS: Percentage of overweight is commonly considered as a good surrogate measure for determining overweight and obesity in children of both sexes. However, this study has clarified that body fat accumulation is overestimated in children with short stature when using the POW measurement.

Dimethyl Fumarate Induces Apoptosis via Inhibition of NF-κB and Enhances the Effect of Paclitaxel and Adriamycin in Human TNBC Cells.

Triple-negative breast cancer (TNBC) has the poorest prognosis of all breast cancer subtypes. Recently, the activation of NF-κB, which is involved in the growth and survival of malignant tumors, has been demonstrated in TNBC, suggesting that NF-κB may serve as a new therapeutic target. In the present study, we examined whether dimethyl fumarate (DMF), an NF-κB inhibitor, induces apoptosis in TNBC cells and enhances the apoptosis-inducing effect of paclitaxel and adriamycin. Cell survival was analyzed by the trypan blue assay and apoptosis assay. Protein detection was examined by immunoblotting. The activation of NF-κB p65 was correlated with poor prognosis in patients with TNBC. DMF induced apoptosis in MDA-MB-231 and BT-549 cells at concentrations that were non-cytotoxic to the normal mammary cell line MCF-10A. Furthermore, DMF inhibited NF-κB nuclear translocation and Survivin, XIAP, Bcl-xL, and Bcl-2 expression in MDA-MB-231 and BT-549 cells. Moreover, DMF enhanced the apoptosis-inducing effect of paclitaxel and adriamycin in MDA-MB-231 cells. These findings suggest that DMF may be an effective therapeutic agent for the treatment of TNBC, in which NF-κB is constitutively active. DMF may also be useful as an adjuvant therapy to conventional anticancer drugs.

Interleukin 19 suppresses RANKL-induced osteoclastogenesis via the inhibition of NF-κB and p38MAPK activation and c-Fos expression in RAW264.7 cells.

Interleukin 19 (IL-19) is a member of the IL-10 family of cytokines and is known as an inhibitory cytokine. IL-10, also an inhibitory cytokine, suppresses the receptor activator of nuclear factor κB (NF-κB) ligand (RANKL)-induced osteoclast differentiation. However, the effects of IL-19 on osteoclast differentiation are not currently well-understood. In this study, we examined whether IL-19 suppresses osteoclast differentiation in the mouse macrophage-like cell line RAW264.7. We found that IL-19 inhibited RANKL-induced osteoclast differentiation. In addition, IL-19 suppressed RANKL-induced NF-κB and p38 mitogen-activated protein kinase (p38MAPK) activation and c-Fos expression. Moreover, RANKL inhibited IL-19 mRNA expression and secretion in RAW264.7 cells, and the inhibition of the IL-19 function promoted osteoclast differentiation. These results indicate that IL-19 suppressed osteoclast differentiation via the inhibition of NF-κB and p38MAPK activation and c-Fos expression. Furthermore, IL-19 may maintain the osteoclast precursor state, such as monocytes and macrophages. These findings may be useful in the development of osteoclast inhibitors, thereby improving treatments for osteoclast activation-related diseases, such as osteoporosis.

A surgically treated case of severe upper gastrointestinal hemorrhage with gastritis cystica polyposa.

BACKGROUND: Gastritis cystica polyposa (GCP) is a recently recognized entity histologically characterized by hyperplasia and cystic dilatation of the gastric glands spreading through the submucosal layer. Its symptoms include those affecting the upper gastrointestinal tract, such as upper abdominal pain, nausea, and anorexia, although some patients might be asymptomatic. GCP rarely causes severe hemorrhage. Recently, we encountered a GCP case that exhibited severe hemorrhage. CASE PRESENTATION: A 53 year-old man visited the emergency department complaining of hematemesis. He underwent distal gastrectomy and Billroth II reconstruction for duodenal ulcers 32 years ago. Upper gastrointestinal endoscopy detected bleeding from the reddened mucosa at the anastomosis; thus, tentative endoscopic hemostasis was conducted. Despite medical treatment with transfusion, melena with significant hemodynamic impairment persisted. He was treated again with endoscopic hemostasis and interventional radiology (IVR) but remained unresponsive to these procedures. He eventually underwent partial resection of the anastomosis site with Roux-en-Y reconstruction and finally achieved excellent postoperative recovery. Histopathological examination of the resected specimen suggested a GCP bleeding. CONCLUSIONS: GCP can indeed cause severe hemorrhage. Hemorrhage caused by GCP may not respond to endoscopic hemostasis or IVR; therefore, surgical treatment should be decided without delay.

The P-class pentatricopeptide repeat protein PpPPR_21 is needed for accumulation of the psbI-ycf12 dicistronic mRNA in Physcomitrella chloroplasts.

Chloroplast gene expression is controlled by numerous nuclear-encoded RNA-binding proteins. Among these, pentatricopeptide repeat (PPR) proteins are known to be key players in post-transcriptional regulation in chloroplasts. However, the functions of many PPR proteins remain unknown. In this study, we characterized the function of a chloroplast-localized P-class PPR protein PpPPR_21 in Physcomitrella patens. Knockout (KO) mutants of PpPPR_21 exhibited reduced protonemata growth and lower photosynthetic activity. Immunoblot analysis and blue-native gel analysis showed a remarkable reduction of the photosystem II (PSII) reaction center protein and poor formation of the PSII supercomplexes in the KO mutants. To assess whether PpPPR_21 is involved in chloroplast gene expression, chloroplast genome-wide microarray analysis and Northern blot hybridization were performed. These analyses indicated that the psbI-ycf12 transcript encoding the low molecular weight subunits of PSII did not accumulate in the KO mutants while other psb transcripts accumulated at similar levels in wild-type and KO mutants. A complemented PpPPR_21KO moss transformed with the cognate full-length PpPPR_21cDNA rescued the level of accumulation of psbI-ycf12 transcript. RNA-binding experiments showed that the recombinant PpPPR_21 bound efficiently to the 5' untranslated and translated regions of psbImRNA. The present study suggests that PpPPR_21 may be essential for the accumulation of a stable psbI-ycf12mRNA.

Efficient Terahertz Harmonic Generation with Coherent Acceleration of Electrons in the Dirac Semimetal Cd_{3}As_{2}.

We report strong terahertz (∼10^{12} Hz) high harmonic generation at room temperature in thin films of Cd_{3}As_{2}, a three-dimensional Dirac semimetal. Third harmonics are detectable with a tabletop light source and can be as strong as 100 V/cm by applying a fundamental field of 6.5 kV/cm inside the film, demonstrating an unprecedented efficiency for terahertz frequency conversion. Our time-resolved terahertz spectroscopy and calculations also clarify the microscopic mechanism of the nonlinearity originating in the coherent acceleration of Dirac electrons in momentum space. Our results provide clear insights for nonlinear currents of Dirac electrons driven by the terahertz field under the influence of scattering, paving the way toward novel devices for high-speed electronics and photonics based on topological semimetals.

Production of influenza virus-like particles using recombinant insect cells.

Virus-like particles (VLPs) are hollow nanoparticles composed of recombinant viral surface proteins without a virus genome. In the present study, we investigated the production of influenza VLPs using recombinant insect cells. DNA fragments encoding influenza A virus hemagglutinin (HA) and matrix protein 1 (M1) were cloned with the Drosophila BiP signal sequence in plasmid vectors containing a blasticidin and a neomycin resistance gene, respectively. After Trichoplusia ni BTI-TN-5B1-4 (High Five) cells were co-transfected with a pair of constructed plasmid vectors, stably transformed cells were established via incubation with blasticidin and G418. Western blot analyses showed that recombinant High Five cells secreted HA and M1 proteins into the culture supernatant. Immunoprecipitation of the culture supernatant with an anti-HA antibody and transmission electron microscopy suggested that secreted HA and M1 proteins were in a particulate structure with a morphology similar to that of an influenza virus. Hemagglutination assay indicated that expressed HA molecules retained hemagglutination activity. In a shake-flask culture, recombinant cells achieved a high HA yield (≈ 10 µg/ml) comparable to the yields obtained using the baculovirus-insect cell system. Recombinant insect cells may serve as excellent platforms for the efficient production of influenza VLPs for use as safe and effective vaccines and diagnostic antigens.