Abstract
The BOUT++ transport code is run to study the effects of plasma drifts on the divertor out-in asymmetries (DOIAs) of particle and heat fluxes and their decay widths for EAST lower single ...null H-mode discharges. The diamagnetic drift seems to have no effects on the DOIAs of total particle and heat fluxes due to its divergence-free nature. However, it could significantly increase the DOIAs of peak particle and heat fluxes and the flux decay widths. The E × B drift is found to induce a large plasma flow to the divertor region, enhancing the DOIAs of both total and peak particle and heat fluxes and the flux decay widths. Both the radial and poloidal components of the E × B drift are necessary in increasing the DOIAs, however, the radial E × B drift seems to play a more important role. The effects on the DOIAs caused by both diamagnetic and E × B drifts are reversed with the reverse of toroidal magnetic field. The heat flux decay width
λ
q
and spreading width
S
q
are important physical and engineering parameters for the divertors and could be obtained by fitting the heat flux profiles at divertor targets. The
λ
q
at the outer target from the simulation case with all drifts could well match with the multi-machine scaling proposed by Eich and the DOIA of
λ
q
is in reasonable agreement with the scaling proposed by Goldston.
A new low band gap copolymer PBB3 containing 6,6′bithieno3,4-bthiophenyl-2,2′-dicarboxylic acid bis-(2-butyloctyl) ester (BTT) and 4,8-bis(2-butyloctyl)benzo1,2-b:4,5-b′dithiophene (BDT) units was ...synthesized and tested for solar cell efficiency. PBB3 showed a broad absorbance in the near-IR region with a substantially red-shifted (by more than 100 nm) λmax at 790 nm as compared to the PTB series of polymers, which have been previously reported. The PBB3 polymer also showed both a favorable energy level match with PCBM (with a LUMO energy level of −3.29 eV) and a favorable film domain morphology as evidenced by TEM images. Despite these seemingly optimal parameters, a bulk heterojunction (BHJ) photovoltaic device fabricated from a blend of PBB3 and PC71BM showed an overall power conversion efficiency (PCE) of only 2.04% under AM 1.5G/100 mW cm–2. The transient absorption spectra of PBB3 showed the absence of cationic and pseudo charge transfer states that were observed previously in the PTB series polymers, which were also composed of alternating thienothiophene (TT) and BDT units. We compared the spectral features and electronic density distribution of PBB3 with those of PTB2, PTB7, and PTBF2. While PTB2 and PTB7 have substantial charge transfer characteristics and also relatively large local internal dipoles through BDT to TT moieties, PTBF2 and PBB3 have minimized internal dipole moments due to the presence of two adjacent TT units (or two opposing fluorine atoms in PTBF2) with opposite orientations or internal dipoles. PBB3 showed a long-lived excitonic state and the slowest electron transfer dynamics of the series of polymers, as well as the fastest recombination rate of the charge-separated (CS) species, indicating that electrons and holes are more tightly bound in these species. Consequently, substantially lower degrees of charge separation were observed in both PBB3 and PTBF2. These results show that not only the energetics but also the internal dipole moment along the polymer chain may be critical in maintaining the pseudocharge transfer characteristics of these systems, which were shown to be partially responsible for the high PCE device made from the PTB series of low band gap copolymers.
This study aimed to assess the prognostic value of the serum albumin to globulin ratio (AGR) in cholangiocarcinoma patients after surgery.
We retrospectively enrolled 123 cholangiocarcinoma patients ...who underwent surgical treatment between June 2003 and September2014 at the Third Affiliated Hospital of Sun Yat-sen University. Univariate and multivariate analyses using the Cox regression model were performed to determine the prognostic value of AGR.
Univariate analysis suggested that AGR was a predictive factor for (overall survival) OS but not for recurrence free survival (RFS). After adjustment for other risk factors, multivariate analysis showed that AGR remained independently associated with OS. The optimal cut-off point for AGR was determined to be 1.44. Kaplan–Meier curves showed that there was a significantly lower mean survival time in the low AGR group compared to the high AGR group. A low AGR was found to be significantly associated with high alkaline phosphatase, gamma-glutamyl transpeptidase, total bilirubin levels and an advanced American Joint Committee on Cancer TNM stage, but a low hemoglobin level.
In summary, patients with higher AGRs have better outcomes than those with lower AGRs. Preoperative AGR can be a reliable marker for evaluating the prognosis of cholangiocarcinoma patients.
Perioperative bleeding and postsurgical hemorrhage are common in invasive surgical procedures, including orthopedic surgery. Tranexamic acid (TXA) is a pharmacologic agent that acts through an ...antifibrinolytic mechanism to stabilize formed clots and reduce active bleeding. It has been used successfully in orthopedics to reduce perioperative blood loss, particularly in total hip and knee arthroplasty and spine surgery. Numerous research studies have reported favorable safety and efficacy in orthopedic cases, although there is no universal standard on its administration and its use has not yet become the standard of practice. Reported administration methods often depend on the surgeon's preference, with both topical and intravenous routes showing efficacy. The type and anatomic site of the surgery seem to influence the decision making but also result in conflicting opinions. Reported complication rates with TXA use are low. The incidence of both arterial and venous thromboembolic events, particularly deep venous thrombosis and pulmonary embolism, has not been found to be significantly different with TXA use for healthy patients. The route of administration and dosage do not appear to affect complication rates either. However, data on patients with higher-risk conditions are deficient. In addition, TXA has shown potential to reduce blood loss, transfusion rates and volumes, perioperative hemoglobin change, and hospital-related costs at various degrees among the published studies. Conservation of blood products, reduced laboratory costs, and shorter hospital stays are likely the major factors driving the cost savings associated with TXA use. This article reviews current data supporting the safety, efficacy, and cost-effectiveness of TXA in orthopedic surgery.
With development of massively parallel sequencing technologies, there is a substantial need for developing powerful rare variant association tests. Common approaches include burden and non-burden ...tests. Burden tests assume all rare variants in the target region have effects on the phenotype in the same direction and of similar magnitude. The recently proposed sequence kernel association test (SKAT) (Wu, M. C., and others, 2011. Rare-variant association testing for sequencing data with the SKAT. The American Journal of Human Genetics 89, 82-93, an extension of the C-alpha test (Neale, B. M., and others, 2011. Testing for an unusual distribution of rare variants. PLoS Genetics 7, 161-165, provides a robust test that is particularly powerful in the presence of protective and deleterious variants and null variants, but is less powerful than burden tests when a large number of variants in a region are causal and in the same direction. As the underlying biological mechanisms are unknown in practice and vary from one gene to another across the genome, it is of substantial practical interest to develop a test that is optimal for both scenarios. In this paper, we propose a class of tests that include burden tests and SKAT as special cases, and derive an optimal test within this class that maximizes power. We show that this optimal test outperforms burden tests and SKAT in a wide range of scenarios. The results are illustrated using simulation studies and triglyceride data from the Dallas Heart Study. In addition, we have derived sample size/power calculation formula for SKAT with a new family of kernels to facilitate designing new sequence association studies.
Aim
Brown and beige adipose tissues dissipate energy in the form of heat via mitochondrial uncoupling protein 1, defending against hypothermia and potentially obesity. The latter has prompted renewed ...interest in understanding the processes involved in browning to realize the potential therapeutic benefits. To characterize the temporal profile of cold‐induced changes and browning of brown and white adipose tissues in mice.
Methods
Male C57BL/6J mice were singly housed in conventional cages under cold exposure (4 °C) for 1, 2, 3, 4, 5 and 7 days. Food intake and body weight were measured daily. Interscapular brown adipose tissue (iBAT), inguinal subcutaneous (sWAT) and epididymal white adipose tissue (eWAT) were harvested for histological, immunohistochemical, gene and protein expression analysis.
Results
Upon cold exposure, food intake increased, whilst body weight and adipocyte size were found to be transiently reduced. iBAT mass was found to be increased, whilst sWAT and eWAT were found to be transiently decreased. A combination of morphological, genetic (Ucp‐1, Pgc‐1α and Elov13) and biochemical (UCP‐1, PPARγ and aP2) analyses demonstrated the depot‐specific remodelling in response to cold exposure.
Conclusion
Our results demonstrate the differential responses to cold‐induced changes across discrete BAT and WAT depots and support the notion that the effects of short‐term cold exposure are achieved by expansion, activation and increasing thermogenic capacity of iBAT, as well as browning of sWAT and, to a lesser extent, eWAT.
Long-Term Evolution (LTE) over unlicensed spectrum extends LTE technology to the spacious unlicensed spectrum with readily available bandwidth. The provided capacity surge makes it one of the most ...high-profile technologies to meet the explosive growth of mobile traffic demand. Among its different variants, Licensed Assisted Access (LAA) is considered as a promising global solution attributed to its mandatory listen-before-talk (LBT) procedure. Nevertheless, although LBT effectively maintains transmission fairness between LTE and other unlicensed systems (e.g., Wi-Fi), the current LAA protocol specified in 3GPP Release 13 is far from perfect to achieve harmony coexistence. To this end, in this paper, we first develop an analytical model to evaluate the throughput performance of Category 4 (Cat 4) algorithm agreed in 3GPP release 13. Subject to the system fairness constraint, the aggregate throughput of LTE-LAA and Wi-Fi networks is maximized based on a semi branch and bound algorithm. To make the complex optimization tractable, reinforcement learning techniques are introduced to intelligently tune the contention window size for both LTE-LAA and Wi-Fi nodes. Specifically, a cooperative learning algorithm is developed assuming that the information between different systems is exchangeable. A non-cooperative version is subsequently developed to remove the previous assumption for better practicability. Extensive simulations are conducted to demonstrate the performance of the proposed learning algorithms in contrast to the analytical upper bound under various conditions. It is shown that both proposed learning algorithms can significantly improve the total throughput performance while satisfying the fairness constraints. Particularly, the proposed cooperative learning algorithm can closely approach the analytical bound.
Careful selection of processing solvents to tune optimal active layer morphology in a donor‐acceptor copolymer blend PTB7:P(NDI2OD‐T2) yields bulk heterojunction microstructures with intradomain ...percolative pathways and enhanced charge transport. Such microstructures afford all‐polymer solar cells with power conversion efficiencies as high as 2.7%.
The influence of the number-average molecular weight (M n) on the blend film morphology and photovoltaic performance of all-polymer solar cells (APSCs) fabricated with the donor polymer ...poly5-(2-hexyldodecyl)-1,3-thieno3,4-cpyrrole-4,6-dione-alt-5,5-(2,5-bis(3-dodecylthiophen-2-yl)thiophene) (PTPD3T) and acceptor polymer poly{N,N′-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl-alt-5,5′-(2,2′-bithiophene)} (P(NDI2OD-T2); N2200) is systematically investigated. The M n effect analysis of both PTPD3T and N2200 is enabled by implementing a polymerization strategy which produces conjugated polymers with tunable M ns. Experimental and coarse-grain modeling results reveal that systematic M n variation greatly influences both intrachain and interchain interactions and ultimately the degree of phase separation and morphology evolution. Specifically, increasing M n for both polymers shrinks blend film domain sizes and enhances donor–acceptor polymer–polymer interfacial areas, affording increased short-circuit current densities (J sc). However, the greater disorder and intermixed feature proliferation accompanying increasing M n promotes charge carrier recombination, reducing cell fill factors (FF). The optimized photoactive layers exhibit well-balanced exciton dissociation and charge transport characteristics, ultimately providing solar cells with a 2-fold PCE enhancement versus devices with nonoptimal M ns. Overall, it is shown that proper and precise tuning of both donor and acceptor polymer M ns is critical for optimizing APSC performance. In contrast to reports where maximum power conversion efficiencies (PCEs) are achieved for the highest M ns, the present two-dimensional M n optimization matrix strategy locates a PCE “sweet spot” at intermediate M ns of both donor and acceptor polymers. This study provides synthetic methodologies to predictably access conjugated polymers with desired M n and highlights the importance of optimizing M n for both polymer components to realize the full potential of APSC performance.
In vehicular ad hoc networks (VANETs), the IEEE 802.11p is a popular and standardized protocol for communications among vehicles and infrastructure (e.g., roadside units). However, because of a ...limited communication range and the randomly access nature of the carrier sense multiple access with collision avoidance (CSMA/CA) mechanism, the end-to-end delay could be high due to both store-and-catch-up (SAC) delay when the network is temporally disconnected and the channel access contention delay. In this paper, we propose a new method based on fifth-generation device-to-device (D2D) technology to improve the delay performance of VANETs. The basic idea is that direct D2D-based communications among vehicles remove the contention delay and can support longer distance. Specifically, we design a hybrid system with both D2D- and IEEE 802.11p-based communications, where the D2D links are controlled by the cellular base stations (BSs) in the overlay scheme. Each vehicle periodically checks its packet lifetime and requests the BSs to establish D2D links, if needed. The optimal resource allocation problem at the BSs is to select optimal receiver vehicles to establish D2D links and assign proper channels for them so that the total delay is minimized. The problem is equivalent to a maximum weighted independent set problem with dependent weights (MWIS-DW), which is NP-hard. To calculate the weights, an analytical approach is developed to model the expected end-to-end delay. Furthermore, we propose a greedy-based algorithm to solve this problem and develop a theoretical performance lower bound for the algorithm. The effectiveness of the algorithm under various scenarios is evaluated through simulations.
PDF
