Modeling Uranyl Adsorption on MoS2/Mo2CTx Heterostructures Using DFT and BOMD Methods.

Uranium-bearing wastewaters exert a great threat to the ecological environment due to its high radiotoxicity level. The designing and fabrication of novel adsorption materials can be promoted for radionuclide elimination from wastewater. In this work, results from density functional theory and Born-Oppenheimer molecular dynamics simulations are reported for the uranyl adsorption behavior on the MoS2/Mo2CTx heterostructure in the gas phase and in an aqueous environment. Uranyl ions prefer to be adsorbed at deprotonated O sites on the Mo2COH surface and S sites on the MoS2 side of the heterojunctions, resulting in the formation of bidentate configurations. In addition to coordination interaction, H-bond and van der Waals interactions can also play an important role in binding configurations. More importantly, the oxidation state U(VI) can be reduced to U(V) and then to U(IV) caused by the strong reducibility of the Mo2COH surface at room temperature, whereas the uranyl complex can move freely on the MoS2 surface. However, the coordination number of U with respect to H2O in the first hydration shell on the Mo2COH surface remains unchanged and is found to be 3, which is similar to that on the MoS2 surface. This work provides novel nanosorbents for the removal of uranyl from wastewater. The present viewpoint provides valuable mechanistic interpretations for uranyl adsorption and will give a supplement to the experimental research.

Evaluation of Microwave Ablation Efficacy by Strain Elastography and Shear Wave Elastography in ex Vivo Porcine Liver.

The aim of this study was to evaluate the efficacy of microwave ablation by ultrasound (US), strain elastography (SE) and shear-wave elastography (SWE). An ex vivo model of porcine liver was adopted. According to ablation power and duration, 30 samples were divided into three groups: group 1 (45 W, 30 s), group 2 (45 W, 15 s) and group 3 (30 W, 30 s). US was used to measure the largest transverse diameter (D1), vertical diameter (D2) and anteroposterior diameter (D3) of the ablated area. SE was used to measure the largest transverse diameter (SEL1), vertical diameter (SEL2) and anteroposterior diameter (SEL3). The actual size of the ablated area was measured as the largest transverse diameter (L1), vertical diameter (L2) and anteroposterior diameter (L3). SWE values and temperatures were measured in the central lesion (region a), marginal area (region b) and unablated area (region c). At 1 h post-ablation, the values measured by US (D1, D2, D3) were all significantly smaller than the ablated area (L1, L2, L3) in all three groups. Except for SEL2 in group 1, there was no significant difference in the results between SEL and L among the three groups. All SWE results were significantly higher post-ablation than pre-ablation in the central lesion (region a) and marginal area (region b, all p values <0.05). In regions a, b and c, the temperatures measured immediately and 5 min post-ablation were all higher than that measured pre-ablation. These results suggest that SE and SWE can be used to evaluate the ablation efficacy of liver tissue.

Highly Efficient All-Polymer Solar Cells Processed from Nonhalogenated Solvents.

The remarkable advance of all-polymer solar cells (all-PSCs) achieved in the past decades is primarily powered by the innovation of polymer acceptors. However, most of high-performance all-PSCs are dominantly fabricated with halogenated solvents, which are detrimental to human bodies and the environment. Herein, eco-friendly solvent-processed all-PSCs were developed, based on wide-bandgap polymer poly[4,8-bis(5-(2-ethylhexylthio)thiophen-2-yl)-benzo-[1,2-b;4,5-b']dithiophene-alt-2,5-di(butyloctylthiophen-2-yl) -thiazolo[5,4-d]thiazole] (PSTZ) as donor and newly synthesized narrow-bandgap polymer 5,6-dicyano-2,1,3-benzothiadiazole indacenodithiophene (DCNBT-IDT) as acceptor. When processed with o-xylene and THF, PSTZ : DCNBT-IDT-based all-PSCs yielded remarkable power conversion efficiencies of 7.23 and 8.77 % with high short-circuit currents of 12.94 and 14.12 mA cm-2 , respectively. The results indicated that the utilization of an all-polymer blend based on narrow polymer acceptor and compatible polymer donor is an effective strategy for advancing eco-friendly solvent-processed all-PSCs.

Adjusting the photovoltaic performance of big fused ring-based small molecules by tailoring with different modifications.

Three novel A-D-A type small-molecule donor materials, namely AAN-DPP2, AAN(T-DPP)2 and AANT(T-DPP)2, with anthanthrene (AAN) as the electron-donating core, diketopyrrolopyrrole (DPP) as the electron-accepting moiety, and thiophene as π-bridge units, have been designed and synthesized for application in bulk-heterojunction (BHJ) organic solar cells (OSCs). Compared to AAN-DPP2, devices based on AAN(T-DPP)2 and AANT(T-DPP)2 show better photovoltaic performance due to broader absorption and better planarity of the molecular backbone. A maximum power conversion efficiency (PCE) of 2.33% with a short-circuit current density (J sc) of 6.82 mA cm-2 and a fill factor (FF) of 39.80 was obtained in the AAN(T-DPP)2/PC71BM-based solar cells. This is resulting from the suitable thickness of the active layer, improving the ability of catching light and decreasing the twist angle of the backbone by inserting a thiophene spacer. The results indicate that strategic substitution of π-bridges and side-chains in A-D-A type SMs is an efficient strategy to improve photovoltaic performance.

A Comparative Atlas-Based Recognition of Mild Cognitive Impairment With Voxel-Based Morphometry.

An accurate and reliable brain partition atlas is vital to quantitatively investigate the structural and functional abnormalities in mild cognitive impairment (MCI), generally considered to be a prodromal phase of Alzheimer's disease. In this paper, we proposed an automated structural classification method to identify MCI from healthy controls (HC) and investigated whether the classification performance was dependent on the brain parcellation schemes, including Automated Anatomical Labeling (AAL-90) atlas, Brainnetome (BN-246) atlas, and AAL-1024 atlas. In detail, structural magnetic resonance imaging (sMRI) data of 69 MCI patients and 63 HC matched well on gender, age, and education level were collected and analyzed with voxel-based morphometry method first, then the volume features of every region of interest (ROI) belonging to the above-mentioned three atlases were calculated and compared between MCI and HC groups, respectively. At last, the abnormal volume features were selected as the classification features for a proposed support vector machine based identification method. After the leave-one-out cross-validation to estimate the classification performance, our results reported accuracies of 83, 92, and 89% with AAL-90, BN-246, and AAL-1024 atlas, respectively, suggesting that future studies should pay more attention to the selection of brain partition schemes in the atlas-based studies. Furthermore, the consistent atrophic brain regions among three atlases were predominately located at bilateral hippocampus, bilateral parahippocampal, bilateral amygdala, bilateral cingulate gyrus, left angular gyrus, right superior frontal gyrus, right middle frontal gyrus, left inferior frontal gyrus, and left precentral gyrus.

Highly Efficient Nonfullerene Polymer Solar Cells Enabled by a Copper(I) Coordination Strategy Employing a 1,3,4-Oxadiazole-Containing Wide-Bandgap Copolymer Donor.

A novel wide-bandgap copolymer of PBDT-ODZ based on benzo[1,2-b:4,5-b' ]dithiophene (BDT) and 1,3,4-oxadiazole (ODZ) blocks is developed for efficient nonfullerene polymer solar cells (NF-PSCs). PBDT-ODZ exhibits a wide bandgap of 2.12 eV and a low-lying highest occupied molecular orbital (HOMO) level of -5.68 eV, which could match well with the low-bandgap acceptor of 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone)-5,5,11,11-tetrakis(4-hexylthienyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']-dithiophene (ITIC-Th), inducing a good complementary absorption from 300 to 800 nm and a minimal HOMO level offset (0.1 eV). The PBDT-ODZ:ITIC-Th devices exhibit a large open-circuit voltage (Voc ) of 1.08 eV and a low energy loss (Eloss ) of 0.50 eV, delivering a high power conversion efficiency (PCE) of 10.12%. By adding a small amount of copper(I) iodide (CuI) as an additive to form coordination complexes in the active blends, much higher device performances are achieved due to the improved absorption and crystallinity. After incorporating 4% of CuI, the PCE is elevated to 12.34%, with a Voc of 1.06 V, a Jsc of 17.1 mA cm-2 and a fill factor of 68.1%. This work not only provides a novel oxadiazole-containing wide-bandgap polymeric donor candidate for high-performance NF-PSCs but also presents an efficient morphology-optimization approach to elevate the PCE of NF-PSCs for future practical applications.

Correlations between anterior wall motion velocity of ascending aorta measured by quantitative tissue velocity image and left ventricular geometry as well as left heart function in hypertension patients.

BACKGROUD: This study aimed to analyze the correlations between anterior wall motion velocity of ascending aorta measured by quantitative tissue velocity image (QTVI) technique and left ventricular geometry as well as left heart function to evaluate its value of clinical application. METHODS: One hundred ten hypertension patients and 35 healthy controls were included, divided into left ventricular concentric remodeling group and left ventricular hypertrophy group. The QTVI technique was used to obtain the velocity curve of anterior wall of ascending aorta, the peak systolic velocity (Vs), peak velocity of early diastolic motion (Ve) and peak velocity of late diastolic motion (Va). The single-plane Simpson method was utilized to measure the left ventricular ejection fraction (EF). The QTVI method was used to obtain the index of left ventricular diastolic function (Em/Am). RESULTS: Compared to control group, both Vs and Ve values significantly reduced in hypertension group (P<0.05). Both Vs and Ve values were significantly negatively correlated with LVMI and RWT (P<0.01). The Va value was negatively correlated with LVMI (P<0.05). The Vs value was significantly positively correlated with EF value (P<0.01). The Ve value was significantly positively correlated with both EF and Em/Am (P<0.01). The Va value was positive correlated with Em/Am (P<0.05). CONCLUSIONS: The QTVI anterior wall velocity of ascending aorta could be indicator for the geometric patterns and function of left ventricle, which may provide a simple and comprehensive method for clinical assessment of hypertensive heart disease.

Chalcogen-Atom-Annulated Perylene Diimide Trimers for Highly Efficient Nonfullerene Polymer Solar Cells.

This communication reports the synthesis of two novel chalcogen-atom-annulated perylene diimide (PDI) trimers with twisted structures, TriPDI-S and TriPDI-Se, for efficient nonfullerene polymer solar cells. TriPDI-Se exhibits more compact molecular arrangement due to the stronger intermolecular interactions induced by the selenium atom. This selenium annulation endows TriPDI-Se with improved absorption and crystallinity in its blend film. The resulting devices exhibit enhanced Jsc of 17.15 mA cm-2 and fill factor (FF) of 66.8%, which are much higher than those of TriPDI-S devices (Jsc = 16.71 mA cm-2 ; FF = 63.6%). Although TriPDI-Se exhibits lower-lying energy levels, TriPDI-Se devices still obtain a higher Voc of 0.77 V compared to TriPDI-S devices (Voc = 0.74 V), which is mainly originated from the reduced recombination in the related devices. Finally, the power conversion efficiency is significantly elevated from 7.86% for TriPDI-S devices to 8.82% for TriPDI-Se devices.

Side-Chain Influence of Wide-Bandgap Copolymers Based on Naphtho[1,2-b:5,6-b]bispyrazine and Benzo[1,2-b:4,5-b']dithiophene for Efficient Photovoltaic Applications.

In this work, we reported new types of wide-bandgap copolymers, PBDTA-NPz, PBDTT-NPz, PBDTF-NPz, and PBDTP-NPz, on the basis of the naphtho[1,2-b:5,6-b]bispyrazine (NPz) acceptor building block for efficient photovoltaic applications. The influencing factors of the introduced side chains, including alkoxyl, alkylthienyl, alkylfuryl, and alkoxylphenyl, were investigated in detail. These copolymers possessed wide bandgaps ranging from 1.79 to 1.88 eV with different nonconjugated or conjugated side chains. They also possessed deep highest-occupied molecular orbital levels of less than -5.25 eV, which allowed the achievement of high Voc's from their polymer solar cells (PSCs). The X-ray diffraction results indicated their excellent crystallinity and molecular stacking features, especially for PBDTF-NPz containing alkylfuryl side chains. Their photovoltaic performances were measured using bulk-heterojunction single-junction PSCs with a configuration of ITO/PEDOT:PSS/copolymer:PC71BM/Ca/Al under the same processing conditions. Different side chains of NPz-based copolymers induced largely different device performances. Without the additive, 1,8-diiodooctane (DIO), the primary PBDTA-NPz, PBDTT-NPz, PBDTF-NPz, and PBDTP-NPz devices showed power conversion efficiencies (PCEs) of 4.53, 6.09, 7.06, and 3.49%, respectively. On adding 3 vol % DIO, the device performances were elevated to a higher level. The PBDTF-NPz devices exhibited the highest PCE of 8.63%, which resulted in improved Voc, Jsc, and FF values caused by their inherent properties. Our results indicated that NPz is a potential acceptor unit to construct high-powered wide-bandgap copolymers for efficient PSCs in the future.

Pronounced Effects of a Triazine Core on Photovoltaic Performance-Efficient Organic Solar Cells Enabled by a PDI Trimer-Based Small Molecular Acceptor.

A novel-small molecular acceptor with electron-deficient 1,3,5-triazine as the core and perylene diimides as the arms is developed as the acceptor material for efficient bulk heterojunction organic solar cells with an efficiency of 9.15%.

Solution-Processable Small Molecules for High-Performance Organic Solar Cells with Rigidly Fluorinated 2,2'-Bithiophene Central Cores.

Small molecules containing an oligothiophene backbone are simple but effective donor materials for organic solar cells (OSCs). In this work, we incorporated rigid 2,2'-bithiophene (BT) or fluorinated 2,2'-bithiophene (FBT) as the central unit and synthesized two novel small molecules (TTH-D3TRh and TTF-D3TRh) with an oligothiophene backbone and 3-ethylrhodanine end groups. Both molecules exhibit good thermal stability as well as strong and broad absorption. The fluorination of the BT central unit made TTF-D3TRh possess a relatively lower-lying HOMO energy level, better molecular stacking, and higher mobility in comparison with those of TTH-D3TRh. Conventional OSCs were fabricated to evaluate the photovoltaic property of these two molecules. Without extra post-treatments, the conventional devices based on TTH-D3TRh and TTF-D3TRh showed high PCEs of 5.00 and 5.80%, respectively. The TTF-D3TRh device exhibited a higher performance, which can be attributed to the improved Voc of 0.92 V, Jsc of 10.04 mA cm(-2), and FF of 62.8%. Using an inverted device structure, the OSCs based on TTH-D3TRh and TTF-D3TRh showed largely elevated PCEs of 5.89 and 7.14%, respectively. The results indicated that the structurally simple TTH-D3TRh and TTF-D3TR molecules are potential donor candidates for achieving highly efficient OSCs. The strategy of fluorination and rigidity designation is an effective approach to develop oligothiophene-based small molecular donors for highly efficient solar cell applications.

Low band gap benzothiophene-thienothiophene copolymers with conjugated alkylthiothieyl and alkoxycarbonyl cyanovinyl side chains for photovoltaic applications.

Alkylthiothieyl substituted benzothiophene (BDT) and alkoxycarbonyl cyanovinyl modified thienothiophene (TT) were copolymerized to obtain a new two dimensional low band gap polymer PBDTTT-S-CN, which exhibited a promising efficiency of 7.0% in organic solar cells.

Side-chain engineering of benzodithiophene-fluorinated quinoxaline low-band-gap co-polymers for high-performance polymer solar cells.

A new series of donor-acceptor co-polymers based on benzodithiophene and quinoxaline with various side chains have been developed for polymer solar cells. The effect of the degree of branching and dimensionality of the side chains were systematically investigated on the thermal stability, optical absorption, energy levels, molecular packing, and photovoltaic performance of the resulting co-polymers. The results indicated that the linear and 2D conjugated side chains improved the thermal stabilities and optical absorptions. The introduction of alkylthienyl side chains could efficiently lower the energy levels compared with the alkoxyl-substituted analogues, and the branched alkoxyl side chains could deepen the HOMO levels relative to the linear alkoxyl chains. The branched alkoxyl groups induced better lamellar-like ordering, but poorer face-to-face packing behavior. The 2D conjugated side chains had a negative influence on the crystalline properties of the co-polymers. The performance of the devices indicated that the branched alkoxyl side chains improved the Voc, but decreased the Jsc and fill factor (FF). However, the 2D conjugated side chains would increase the Voc, Jsc, and FF simultaneously. For the first time, our work provides insight into molecular design strategies through side-chain engineering to achieve efficient polymer solar cells by considering both the degree of branching and dimensionality.

Isoindigo fluorination to enhance photovoltaic performance of donor-acceptor conjugated copolymers.

Conjugated copolymers based on isoindigo/fluorinated isoindigo and bis(dialkylthienyl)benzodithiophene, PBDTT-ID and PBDTT-FID, were designed and synthesized for organic photovoltaic applications. The isoindigo fluorination made PBDTT-FID show high PCE of 5.52% and 7.04% in its conventional and inverted PSCs, respectively.

Development of large band-gap conjugated copolymers for efficient regular single and tandem organic solar cells.

We demonstrated the synthesis and characterization of two conjugated copolymers, PBDTFBZO and PBDTFBZS, consisting of dialkylthiol substituted benzo[1,2-b:4,5-b']dithiophene donor and monofluorinated benzotriazole acceptor blocks. The resulting copolymers show large band gaps, deep HOMO and LUMO energy levels. Improved V(oc), J(sc), and FF were obtained at the same time to increase overall efficiencies of their single and tandem polymer solar cells. The enhanced V(oc) can be ascribed to a low-lying HOMO energy level by incorporating dialkylthiol and fluorine substituents on the polymer backbone. The improvement in J(sc) and FF are likely due to high carrier mobility, suppressed charge recombination, and fine nanostructure morphology. A 7.74% PCE was achieved from the regular single device based on PBDTFBZS:PC71BM blend film with 3% 1,8-diiodooctane (DIO) additive. In combination with low band gap diketopyrrolopyrrole (DPP)-based copolymer, tandem devices based on PBDTFBZS exhibited high PCE up to 9.40%. The results indicate that PBDTFBZO and PBDTFBZS are promising polymer donor materials for future application of large-area polymer solar cells.

Assessment of the role of brine shrimp Artemia in white spot syndrome virus (WSSV) transmission.

Challenge tests with Artemia four different development stages (nauplii, metanauplii, pseudoadults and adults) to white spot syndrome virus was carried out by immersion challenge and virus-phytoplankton adhesion route in order to asses the possibility of Artemia acting as a vector of WSSV to penaeid shrimp Litopenaeus vannamei postlarvae. The WSSV succeeded in infecting four stages Artemia, and nested-PCR detection for WSSV revealed positive results to virus-phytoplankton adhesion route. No mass mortalities were observed in penaeid shrimp postlarvae fed with WSSV-positive Artemia which exposed to WSSV by virus-phytoplankton adhesion route, whereas WSSV DNA detected in penaeid shrimp postlarvae by nested-PCR. By contrary, no WSSV-positive was detected in any animal fed with WSSV-negative Artemia. These results indicated that Artemia could serve as a vector in WSSV transmission.