The electronic transport behaviour of materials determines their suitability for technological applications. We develop a computationally efficient method for calculating carrier scattering rates of ...solid-state semiconductors and insulators from first principles inputs. The present method extends existing polar and non-polar electron-phonon coupling, ionized impurity, and piezoelectric scattering mechanisms formulated for isotropic band structures to support highly anisotropic materials. We test the formalism by calculating the electronic transport properties of 23 semiconductors, including the large 48 atom CH
NH
PbI
hybrid perovskite, and comparing the results against experimental measurements and more detailed scattering simulations. The Spearman rank coefficient of mobility against experiment (r
= 0.93) improves significantly on results obtained using a constant relaxation time approximation (r
= 0.52). We find our approach offers similar accuracy to state-of-the art methods at approximately 1/500th the computational cost, thus enabling its use in high-throughput computational workflows for the accurate screening of carrier mobilities, lifetimes, and thermoelectric power.
Band convergence is considered a clear benefit to thermoelectric performance because it increases the charge carrier concentration for a given Fermi level, which typically enhances charge ...conductivity while preserving the Seebeck coefficient. However, this advantage hinges on the assumption that interband scattering of carriers is weak or insignificant. With first-principles treatment of electron-phonon scattering in the CaMg
Sb
-CaZn
Sb
Zintl system and full Heusler Sr
SbAu, we demonstrate that the benefit of band convergence can be intrinsically negated by interband scattering depending on the manner in which bands converge. In the Zintl alloy, band convergence does not improve weighted mobility or the density-of-states effective mass. We trace the underlying reason to the fact that the bands converge at a one k-point, which induces strong interband scattering of both the deformation-potential and the polar-optical kinds. The case contrasts with band convergence at distant k-points (as in the full Heusler), which better preserves the single-band scattering behavior thereby successfully leading to improved performance. Therefore, we suggest that band convergence as thermoelectric design principle is best suited to cases in which it occurs at distant k-points.
COVID-19, a global pandemic, has caused over 750,000 deaths worldwide as of August 2020. A vaccine or remedy for SARS-CoV-2, the virus responsible for COVID-19, is necessary to slow down the spread ...and lethality of COVID-19. However, there is currently no effective treatment available against SARS-CoV-2. In this report, we demonstrated that EGCG and theaflavin, the main active ingredients of green tea and black tea, respectively, are potentially effective to inhibit SARS-CoV-2 activity. Coronaviruses require the 3CL-protease for the cleavage of its polyprotein to make individual proteins functional. EGCG and theaflavin showed inhibitory activity against the SARS-CoV-2 3CL-protease in a dose-dependent manner, and the half inhibitory concentration (IC50) was 7.58 μg/ml for EGCG and 8.44 μg/ml for theaflavin. In addition, we did not observe any cytotoxicity for either EGCG or theaflavin at the concentrations tested up to 40 μg/ml in HEK293T cells. These results suggest that upon further study, EGCG and theaflavin can be potentially useful to treat COVID-19.
AMP-activated protein kinase (AMPK) regulates autophagy initiation when intracellular ATP level decreases. However, the role of AMPK during autophagosome maturation is not fully understood. Here, we ...report that AMPK contributes to efficient autophagosome maturation and lysosomal fusion. Using CRISPR-Cas9 gene editing, we generated AMPK α1 knockout HEK293T cell lines, in which starvation-induced autophagy is impaired. Compound C, an AMPK-independent autophagy inducer, and trehalose, an mTOR-independent autophagy inducer were used to examine the role of AMPK in autophagosome maturation and lysosomal fusion. While the treatment of control cells with either compound C or trehalose induces activation of autophagosomes as well as autolysosomes, the treatment of AMPK α1 knockout cells with compound C or trehalose induces mainly activation of autophagosomes, but not autolysosomes. We demonstrate that this effect is due to interference with the fusion of autophagosomes with lysosomes in AMPK α1 knockout cells. The transient expression of AMPK α1 can rescue autophagosome maturation. These results indicate that AMPK α1 is required for efficient autophagosome maturation and lysosomal fusion.
Face masks are used to protect the wearer from harmful external air and to prevent transmission of viruses from air exhaled by potentially infected wearers to the surrounding people. In this study, ...we examined the potential utility of masks for collecting viruses contained in exhaled breath and detected the collected viruses via various molecular tests. Using KF94 masks, the inner electrostatic filter was selected for virus collection, and an RNA extraction protocol was developed for the face mask. Virus detection in worn mask samples was performed using PCR and rolling circle amplification (RCA) tests and four different target genes (N, E, RdRp, and ORF1ab genes). The present study confirmed that the mask sample tests showed positive SARS-CoV-2 results, similar to the PCR tests using nasopharyngeal swab samples. In addition, the quantity of nucleic acid collected in the masks linearly increased with wearing time. These results suggest that samples for SARS-CoV-2 tests can be collected in a noninvasive, quick, and easy method by simply submitting worn masks from subjects, which can significantly reduce the hassle of waiting at airports or public places and concerns about cross-infection. In addition, it is expected that miniaturization technology will integrate PCR assays on face masks in the near future, and mask-based self-diagnosis would play a significant role in resolving the pandemic situation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The COVID-19 pandemic has resulted in a huge number of deaths from 2020 to 2021; however, effective antiviral drugs against SARS-CoV-2 are currently under development. Recent studies have ...demonstrated that green tea polyphenols, particularly EGCG, inhibit coronavirus enzymes as well as coronavirus replication in vitro. Herein, we examined the inhibitory effect of green tea polyphenols on coronavirus replication in a mouse model. We used epigallocatechin gallate (EGCG) and green tea polyphenols containing more than 60% catechin (GTP60) and human coronavirus OC43 (HCoV-OC43) as a surrogate for SARS-CoV-2. Scanning electron microscopy analysis results showed that HCoV-OC43 infection resulted in virion particle production in infected cells. EGCG and GTP60 treatment reduced coronavirus protein and virus production in the cells. Finally, EGCG- and GTP60-fed mice exhibited reduced levels of coronavirus RNA in mouse lungs. These results demonstrate that green tea polyphenol treatment is effective in decreasing the level of coronavirus in vivo.
The coronavirus disease (COVID-19) pandemic has resulted in more than six million deaths by October 2022. Vaccines and antivirals for severe acute respiratory syndrome coronavirus 2 are now ...available; however, more effective antiviral drugs are required for effective treatment. Here, we report that a potent AMP-activated protein kinase (AMPK) inhibitor, compound C/dorsomorphin, inhibits the replication of the human coronavirus OC43 strain (HCoV-OC43). We examined HCoV-OC43 replication in control and AMPK-knockout (KO) cells and found that the virus replication decreased in AMPK-KO cells. Next, we examined the effect of the AMPK inhibitor, compound C on coronavirus replication. Compound C treatment efficiently inhibited the replication and decreased the coronavirus-induced cytotoxicity, further inhibiting autophagy. In addition, treatment with compound C in combination with chloroquine synergistically inhibited coronavirus replication. These results suggest that compound C can be considered as a potential drug candidate for COVID-19.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Coronavirus can cause various diseases, from mild symptoms to the recent severe COVID-19. The coronavirus RNA genome is frequently mutated due to its RNA nature, resulting in many pathogenic and ...drug-resistant variants. Therefore, many medicines should be prepared to respond to the various coronavirus variants. In this report, we demonstrated that Forsythia viridissima fruit ethanol extract (FVFE) effectively reduces coronavirus replication. We attempted to identify the active compounds and found that actigenin from FVFE effectively reduces human coronavirus replication. Arctigenin treatment can reduce coronavirus protein expression and coronavirus-induced cytotoxicity. These results collectively suggest that arctigenin is a potent natural compound that prevents coronavirus replication.
Background Components of metabolic syndrome have been associated with kidney stone disease, but little evidence is available to support a relationship between metabolic syndrome and kidney stone ...development in healthy large screened populations. Study Design Cross-sectional analysis. Setting & Participants Data were obtained from 34,895 individuals who underwent general health screening tests between January 2006 and December 2006 at the Asan Medical Center. Predictor Metabolic syndrome was defined according to criteria established by the National Cholesterol Education Program Adult Treatment Panel III, American Heart Association, and National Heart, Lung, and Blood Institute. Outcomes & Measurements The presence of kidney stones was evaluated using computed tomography or ultrasonography. Results Of all those screened, 839 (2.4%) had radiologic evidence of kidney stones and metabolic syndrome was diagnosed in 4,779 (13.7%). The multivariable-adjusted OR for kidney stones increased with an increasing quintile of waist circumference and systolic/diastolic blood pressure ( P < 0.001). Age, sex, hypertension, and metabolic syndrome status were independent risk factors for kidney stones. The presence of metabolic syndrome had an OR of 1.25 (95% CI, 1.03-1.50) for kidney stone prevalence. In participants with hypertension, the OR for the presence of kidney stones was 1.47 (95% CI, 1.25-1.71) compared with that for participants without hypertension after adjustment for other variables. Limitations Cross-sectional design, absence of stone composition. Conclusion Metabolic syndrome is associated with a significantly increased risk of kidney stone development. Our findings suggest the need for interventional studies to test the effects of preventing and treating metabolic syndrome on the risk of kidney stone development.
We previously reported that CD133, as a putative cancer stem cell marker, plays an important role in cell proliferation and invasion in colon cancer. To understand the role of CD133 expression in ...colon cancer, we evaluated the inhibitory effect of CD133 in colon cancer cells. In this study, we generated CD133knockout colon cancer cells (LoVo) using the CRISPR-Cas9 gene editing system. CD133+ colon cancer cells (LoVo) were infected with the lentiviral vector carrying CD133 gRNA and purified cell by culturing single cell colonies. CD133knockout cells was validated by western blot and flow cytometry analysis. In functional study, we observed a significant reduction in cell proliferation and colony formation in CRISPR-Cas9 mediated CD133 knockout cells in compare with control (P < 0.001). We also found the anticancer effect of stattic was dependent on CD133 expression in colon cancer cells. Although CD133knockout cells could not completely block the tumorigenic property, they showed remarkable inhibitory effects on the ability of cell migration and invasion (P < 0.001). In addition, we examined the epithelial mesenchymal transition (EMT)-related protein expression by western blot. The result clearly showed a loss of vimentin expression in CD133knockout cells. Therefore, CRISPR-Cas9 mediated CD133knockout can be an effective treatment modality for CD133+ colon cancer through reducing the characteristics of cancer stem cells.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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