32 research outputs found
High-efficiency photoelectric detector based on a p-n homojunction of monolayer black phosphorus
We numerically investigate the high-efficiency photovoltaic effect in lateral
p-n homojunction based on monolayer black phosphorus (MBP) by using the
non-equilibrium Green's function combined with the density functional theory.
Due to the built-in electric field of the p-n junction and the wrinkle
structure of MBP, the photocurrent excited by either linearly or elliptically
polarized light is significantly enhanced in a wide photon energy range.
Moreover, because of the electron-photon interaction, the photocurrent is
related to atomic orbitals through the polarizing angle of polarized light.
Therefore, we can read the orbital information of the band structure from the
polarizing angular distribution of photocurrent. These findings suggest the
promising application of MBP-based p-n homojunction in high-efficiency
photoelectric devices and orbital-resolved photovoltaic detection
Effects of Heavy Metal Stress on Physiology, Hydraulics, and Anatomy of Three Desert Plants in the Jinchang Mining Area, China
The physiological mechanisms and phytoremediation effects of three kinds of native quinoa in a desert mining area were studied. We used two different types of local soils (native soil and tailing soil) to analyze the changes in the heavy metal content, leaf physiology, photosynthetic parameters, stem hydraulics, and anatomical characteristics of potted quinoa. The results show that the chlorophyll content, photosynthetic rate, stomatal conductance, and transpiration rate of Kochia scoparia were decreased, but intercellular CO2 concentration (Ci) was increased under heavy metal stress, and the net photosynthetic rate (Pn) was decreased due to non-stomatal limitation. The gas exchange of Chenopodium glaucum and Atriplex centralasiatica showed a decrease in Pn, stomatal conductance (Gs), and transpiration rate (E) due to stomatal limitation. The three species showed a similar change in heavy metal content; they all showed elevated hydraulic parameters, decreased vessel density, and significantly thickened vessel walls under heavy metal stress. Physiological indicators such as proline content and activity of superoxide dismutase (SOD) and peroxidase (POD) increased, but the content of malondialdehyde (MDA) and glutathione (GSH), as well as catalase (CAT) activity, decreased in these three plants. Therefore, it can be concluded that these three species of quinoa, possibly the most dominant 30 desert plants in the region, showed a good adaptability and accumulation capacity under the pressure of heavy metal stress, and these plants can be good candidates for tailings remediation in the Jinchang desert mining area
A physicochemical double-cross-linked gelatin hydrogel with enhanced antibacterial and anti-inflammatory capabilities for improving wound healing
Abstract Background Skin tissue is vital in protecting the body from injuries and bacterial infections. Wound infection caused by bacterial colonization is one of the main factors hindering wound healing. Wound infection caused by colonization of a large number of bacteria can cause the wound to enter a continuous stage of inflammation, which delays wound healing. Hydrogel wound dressing is composed of natural and synthetic polymers, which can absorb tissue fluid, improve the local microenvironment of wound, and promote wound healing. However, in the preparation process of hydrogel, the complex preparation process and poor biological efficacy limit the application of hydrogel wound dressing in complex wound environment. Therefore, it is particularly important to develop and prepare hydrogel dressings with simple technology, good physical properties and biological effects by using natural polymers. Results In this study, a gelatin-based (Tsg-THA&Fe) hydrogel was created by mixing trivalent iron (Fe3+) and 2,3,4-trihydroxybenzaldehyde (THA) to form a complex (THA&Fe), followed by a simple Schiff base reaction with tilapia skin gelatin (Tsg). The gel time and rheological properties of the hydrogels were adjusted by controlling the number of complexes. The dynamic cross-linking of the coordination bonds (o-phthalmictriol-Fe3+) and Schiff base bonds allows hydrogels to have good self-healing and injectable properties. In vitro experiments confirmed that the hydrogel had good biocompatibility and biodegradability as well as adhesion, hemostasis, and antibacterial properties. The feasibility of Tsg-THA&Fe hydrogel was studied by treating rat skin trauma model. The results showed that compared with ComfeelÂź Plus Transparent dressing, the Tsg-THA&Fe hydrogel could obvious reduce the number of microorganisms, prevent bacterial colonization, reduce inflammation and accelerate wound healing. Local distribution of the Tsg-THA&Fe hydrogel in the skin tissue did not cause organ toxicity. Conclusions In summary, the preparation process of Tsg-THA&Fe hydrogel is simple, with excellent performance in physical properties and biological efficacy. It can effectively relieve inflammation and control the colonization of wound microbes, and can be used as a multi-functional dressing to improve wound healing. Graphical Abstrac
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Patient-Specific MRI-Based Right Ventricle Models Using Different Zero-Load Diastole and Systole Geometries for Better Cardiac Stress and Strain Calculations and Pulmonary Valve Replacement Surgical Outcome Predictions.
BACKGROUND:Accurate calculation of ventricular stress and strain is critical for cardiovascular investigations. Sarcomere shortening in active contraction leads to change of ventricular zero-stress configurations during the cardiac cycle. A new model using different zero-load diastole and systole geometries was introduced to provide more accurate cardiac stress/strain calculations with potential to predict post pulmonary valve replacement (PVR) surgical outcome. METHODS:Cardiac magnetic resonance (CMR) data were obtained from 16 patients with repaired tetralogy of Fallot prior to and 6 months after pulmonary valve replacement (8 male, 8 female, mean age 34.5 years). Patients were divided into Group 1 (n = 8) with better post PVR outcome and Group 2 (n = 8) with worse post PVR outcome based on their change in RV ejection fraction (EF). CMR-based patient-specific computational RV/LV models using one zero-load geometry (1G model) and two zero-load geometries (diastole and systole, 2G model) were constructed and RV wall thickness, volume, circumferential and longitudinal curvatures, mechanical stress and strain were obtained for analysis. Pairwise T-test and Linear Mixed Effect (LME) model were used to determine if the differences from the 1G and 2G models were statistically significant, with the dependence of the pair-wise observations and the patient-slice clustering effects being taken into consideration. For group comparisons, continuous variables (RV volumes, WT, C- and L- curvatures, and stress and strain values) were summarized as mean ± SD and compared between the outcome groups by using an unpaired Student t-test. Logistic regression analysis was used to identify potential morphological and mechanical predictors for post PVR surgical outcome. RESULTS:Based on results from the 16 patients, mean begin-ejection stress and strain from the 2G model were 28% and 40% higher than that from the 1G model, respectively. Using the 2G model results, RV EF changes correlated negatively with stress (r = -0.609, P = 0.012) and with pre-PVR RV end-diastole volume (r = -0.60, P = 0.015), but did not correlate with WT, C-curvature, L-curvature, or strain. At begin-ejection, mean RV stress of Group 2 was 57.4% higher than that of Group 1 (130.1±60.7 vs. 82.7±38.8 kPa, P = 0.0042). Stress was the only parameter that showed significant differences between the two groups. The combination of circumferential curvature, RV volume and the difference between begin-ejection stress and end-ejection stress was the best predictor for post PVR outcome with an area under the ROC curve of 0.855. The begin-ejection stress was the best single predictor among the 8 individual parameters with an area under the ROC curve of 0.782. CONCLUSION:The new 2G model may be able to provide more accurate ventricular stress and strain calculations for potential clinical applications. Combining morphological and mechanical parameters may provide better predictions for post PVR outcome
Targeting the cGASâSTING Pathway Inhibits Peripheral Tâcell Lymphoma Progression and Enhances the Chemotherapeutic Efficacy
Abstract Peripheral Tâcell lymphoma (PTCL) is a highly heterogeneous group of mature Tâcell malignancies. The efficacy of current firstâline treatment is dismal, and novel agents are urgently needed to improve patient outcomes. A close association between the cyclic GMPâAMP synthaseâstimulator of interferon genes (cGASâSTING) pathway and tumor promotion exists, revealing prospective therapeutic targets. This study, investigates the role of the cGASâSTING pathway and its underlying mechanisms in PTCL progression. Singleâcell RNA sequencing showes that the cGASâSTING pathway is highly expressed and closely associated with PTCL proliferation. cGAS inhibition suppresses tumor growth and impaires DNA damage repair. Moreover, Cdc2âlike kinase 1 (CLK1) is critical for residual tumor cell survival after treatment with cGAS inhibitors, and CLK1 suppression enhances sensitivity to cGAS inhibitors. Singleâcell dynamic transcriptomic analysis indicates reduced proliferationâassociated nascent RNAs as the underlying mechanism. In firstâline therapy, chemotherapyâtriggered DNA damage activates the cGASâSTING pathway, and cGAS inhibitors can synergize with chemotherapeutic agents to kill tumors. The cGASâSTING pathway is oncogenic in PTCL, whereas targeting cGAS suppresses tumor growth, and CLK1 may be a sensitivity indicator for cGAS inhibitors. These findings provide a theoretical foundation for optimizing therapeutic strategies for PTCL, especially in patients with relapsed/refractory disease
Discovery of a Series of 2,5-Diaminopyrimidine Covalent Irreversible Inhibitors of Brutonâs Tyrosine Kinase with in Vivo Antitumor Activity
Brutonâs tyrosine kinase (Btk)
is an attractive drug target for treating several B-cell lineage cancers.
Ibrutinib is a first-in-class covalent irreversible Btk inhibitor
and has demonstrated impressive effects in multiple clinical trials.
Herein, we present a series of novel 2,5-diaminopyrimidine covalent
irreversible inhibitors of Btk. Compared with ibrutinib, these inhibitors
exhibited a different selectivity profile for the analyzed kinases
as well as a dual-action mode of inhibition of both Btk activation
and catalytic activity, which counteracts a negative regulation loop
for Btk. Two compounds from this series, <b>31</b> and <b>38</b>, showed potent antiproliferative activities toward multiple
B-cell lymphoma cell lines, including germinal center B-cell-like
diffuse large B cell lymphoma (GCB-DLBCL) cells. In addition, compound <b>31</b> significantly prevented tumor growth in a mouse xenograft
model
Comparison of RV wall thickness, circumferential and longitudinal curvature and stress/strain between Group 1 and Group 2 at begin-filling, end-filling, begin-ejection, and end-ejection showing stress is the only parameter with significant difference between the two groups.
<p>Comparison of RV wall thickness, circumferential and longitudinal curvature and stress/strain between Group 1 and Group 2 at begin-filling, end-filling, begin-ejection, and end-ejection showing stress is the only parameter with significant difference between the two groups.</p
Demographic and CMR data before and after PVR.
<p>Demographic and CMR data before and after PVR.</p