Thermodynamic Origins of Structural Metastability in Two-Dimensional Black Arsenic

Two-dimensional (2D) materials have aroused considerable research interests owing to their potential applications in nanoelectronics and optoelectronics. Thermodynamic stability of 2D structures inevitably affects the performance and power consumption of the fabricated nanodevices. Black arsenic (b-As), as a cousin of black phosphorus, has presented the extremely high anisotropy in physical properties. However, the systematic research on structural stability of b-As is still lack. Herein, we demonstrated the detailed analysis on structural metastability of the natural b-As, and determined its existence conditions in terms of two essential thermodynamic variables as hydrostatic pressure and temperature. Our results confirmed that b-As can only survive below 0.7 GPa, and then irreversibly transform to gray arsenic, in consistent with our theoretical calculations. Furthermore, thermal annealing strategy was developed to precisely control the thickness of b-As flake, and it sublimates at 300 oC. These results could pave the way for 2D b-As in many promising applications.Comment: 28 pages, 4 figure

Experimental observation of highly anisotropic elastic properties of two-dimensional black arsenic

Anisotropic two-dimensional layered materials with low-symmetric lattices have attracted increasing attention due to their unique orientation-dependent mechanical properties. Black arsenic (b-As), with the puckered structure, exhibits extreme in-plane anisotropy in optical, electrical and thermal properties. However, experimental research on mechanical properties of b-As is very rare, although theoretical calculations predicted the exotic elastic properties of b-As, such as anisotropic Young's modulus and negative Poisson's ratio. Herein, experimental observations on highly anisotropic elastic properties of b-As were demonstrated using our developed in situ tensile straining setup based on the effective microelectromechanical system. The cyclic and repeatable load-displacement curves proved that Young's modulus along zigzag direction was ~1.6 times greater than that along armchair direction, while the anisotropic ratio of ultimate strain reached ~2.5, attributed to hinge structure in armchair direction. This study could provide significant insights to design novel anisotropic materials and explore their potential applications in nanomechanics and nanodevices.Comment: 19 pages, 5 figure

Highly Anisotropic Elastic Properties of Suspended Black Arsenic Nanoribbons

Anisotropy, as an exotic degree of freedom, enables us to discover the emergent two-dimensional (2D) layered nanomaterials with low in-plane symmetry and to explore their outstanding properties and promising applications. 2D black arsenic (b-As) with puckered structure has garnered increasing attention these years owing to its extreme anisotropy with respect to the electrical, thermal, and optical properties. However, the investigation on mechanical properties of 2D b-As is still lacking, despite much effort on theoretical simulations. Herein, we report the highly anisotropic elastic properties of suspended b-As nanoribbons via atomic force microscope-based nanoindentation. It was found that the extracted Young's modulus of b-As nanoribbons exhibits remarkable anisotropy, which approximates to 72.2 +- 5.4 and 44.3 +- 1.4 GPa along zigzag and armchair directions, respectively. The anisotropic ratio reaches up to ~ 1.6. We expect that these results could lay a solid foundation for the potential applications of 2D anisotropic nanomaterials in the next-generation nanomechanics and optoelectronics.Comment: 17 pages, 5 figure

Intralayer Negative Poisson's Ratio in Two-Dimensional Black Arsenic by Strain Engineering

Negative Poisson's ratio as the anomalous characteristic generally exists in artificial architectures, such as re-entrant and honeycomb structures. The structures with negative Poisson's ratio have attracted intensive attention due to their unique auxetic effect and many promising applications in shear resistant and energy absorption fields. However, experimental observation of negative Poisson's ratio in natural materials barely happened, although various two-dimensional layered materials are predicted in theory. Herein, we report the anisotropic Raman response and the intrinsic intralayer negative Poisson's ratio of two-dimensional natural black arsenic (b-As) via strain engineering strategy. The results were evident by the detailed Raman spectrum of b-As under uniaxial strain together with density functional theory calculations. It is found that b-As was softer along the armchair than zigzag direction. The anisotropic mechanical features and van der Waals interactions play essential roles in strain-dependent Raman shifts and negative Poisson's ratio in the natural b-As along zigzag direction. This work may shed a light on the mechanical properties and potential applications of two-dimensional puckered materials.Comment: 23 pages, 4 figure

A prospective study of specimen eversion to lateral rectum and valgus resection for low rectal cancer

PurposeTo investigate the safety and efficacy of a reverse puncture device (RPD) and specimen eversion of the rectum for resection in total laparoscopic proctectomy.MethodsIn a prospective study from August 2019 to March 2021, 40 patients underwent a procedure with an RPD and specimen eversion of the rectum for total laparoscopic low rectal cancer resection, that is natural orifice specimen extraction surgery (NOSES), were included in the NOSES group. Forty patients in the control group underwent conventional laparoscopic radical resection for low rectal cancer and were included in the LAP group. Intraoperative- and postoperative-related indicators, recovery and inflammatory factors, quality of life (QOL) and mental health were compared.ResultsAll operations were successfully completed. Compared with the LAP group, the NOSES group showed better short-term outcomes, such as time to eating, postoperative pain, and especially postoperative incision-related complications. At the same time, postoperative inflammatory factor levels, psychological trauma, life-related anxiety and depression scores, and QOL were better in the NOSES group than in the LAP group.ConclusionsThe application of an RPD and specimen eversion of the rectum for total laparoscopic low rectal cancer resection is a technically feasible and safe approach with a short-term curative effect

Targeted Delivery of Chlorin e6 via Redox Sensitive Diselenide-Containing Micelles for Improved Photodynamic Therapy in Cluster of Differentiation 44-Overexpressing Breast Cancer

The off-target activation of photosensitizers is one of the most well-known obstacles to effective photodynamic therapy (PDT). The selected activation of photosensitizers in cancer cells is highly desired to overcome this problem. We developed a strategy that enabled diselenide bonds to link hyaluronic acid (HA) and photosensitizer chlorin e6 (Ce6) to assemble the micelles (HA-sese-Ce6 NPs) that can target cancer and achieve a redox responsive release of drugs to enhance the PDT efficiency in breast cancer. The HA was used to form a hydrophilic shell that can target cluster of differentiation 44 (CD44) on the cancer cells. The selenium-containing core is easily dissembled in a redox environment to release Ce6. The triggered release of Ce6 in a redox condition and the positive feedback release by activated Ce6 were observed in vitro. In cytotoxicity assays and in vitro cellular uptake assays, the increased PDT efficiency and targeted internalization of HA-sese-Ce6 NPs in the cells were verified, compared to a free Ce6 treated group. Similar results were showed in the therapeutic study and in vivo fluorescence imaging in an orthotopic mammary fat pad tumor model. In addition, a significant inhibition of metastasis was found after the HA-sese-Ce6 NPs treatment. In general, this study promises an ingenious and easy strategy for improved PDT efficiency

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Artificial intelligence in breast MRI radiogenomics: towards accurate prediction of neoadjuvant chemotherapy responses

Neoadjuvant Chemotherapy (NAC) in breast cancer patients has considerable prognostic and treatment potential and can be tailored to individual patients as part of precision medicine protocols. This work reviews recent advances in artificial intelligence so as to enable the use of radiogeomics for the accurate NAC analysis and prediction. The work addresses a new problem in radiogenomics mining: How to combine structural radiomics information and non-structural genomics information for accurate NAC prediction. This requires the automated extraction of parameters from structural breast radiomics data, and finding non-structural feature vectors with diagnostic value, which then are combined with genomics data acquired from exocrine bodies in blood samples from a cohort of cancer patients to enable accurate NAC prediction. A self-attention-based deep learning approach along with an effective multi-channel tumour image reconstruction algorithm of high dimensionality is proposed. The aim is to generate non-structural feature vectors for accurate prediction of the NAC responses by combining imaging datasets with exocrine body related genomics analysis

Capacity optimization configuration of live gas storage system in independent power systems

As the energy demand and the continuous improvement of environmental performance continuous grow, the use of Independent Power Systems (IPS) is becoming increasingly common. Energy storage facilities not only achieve reliable power supply through IPS, but also face the problem of how to achieve more efficient and energy-saving. Therefore, this paper chose to establish a charged gas storage system (GSS for short here) of an independent power system to establish the mathematical model of the GSS through the Linear programming model, including the energy balance equation of the GSS and the load balance equation of the power system. It then used genetic algorithm (GA) to optimize the capacity of the GSS and obtained the optimal capacity configuration plan. In the simulation experiment analysis of a live GSS in view of GA for capacity optimization configuration, the live GSS proposed in this paper outperformed traditional GSS and battery GSS in terms of performance, power load, energy conversion, and capacity configuration. In terms of power load, the six indexes of regulation capacity, response speed, stability, discharge efficiency, power density and energy storage capacity are compared. Among them, the system capacity designed in this paper is 90, 83, 97, 83 and 90 % respectively, which are much higher than the other two. Among them, the six dimensional power load capacity was outstanding, and the energy conversion efficiency was also around 80 %. The capacity configuration was distributed between 85 and 94. This article proposed a design scheme for an electrified GSS based on GA for capacity optimization configuration, which can better meet the needs of independent power systems and improve their reliability and stability

Induction of highly functional hepatocytes from human umbilical cord mesenchymal stem cells by HNF4α transduction.

To investigate the differentiation potential of human umbilical mesenchymal stem cells (HuMSCs) and the key factors that facilitate hepatic differentiation.HuMSCs were induced to become hepatocyte-like cells according to a previously published protocol. The differentiation status of the hepatocyte-like cells was examined by observing the morphological changes under an inverted microscope and by immunofluorescence analysis. Hepatocyte nuclear factor 4 alpha (HNF4α) overexpression was achieved by plasmid transfection of the hepatocyte-like cells. The expression of proteins and genes of interest was then examined by Western blotting and reverse transcription-polymerase chain reaction (RT-PCR) or real-time RT-PCR methods.Our results demonstrated that HuMSCs can easily be induced into hepatocyte-like cells using a published differentiation protocol. The overexpression of HNF4α in the induced HuMSCs significantly enhanced the expression levels of hepatic-specific proteins and genes. HNF4α overexpression may be associated with liver-enriched transcription factor networks and the Wnt/β-Catenin pathway.The overexpression of HNF4α improves the hepatic differentiation of HuMSCs and is a simple way to improve cellular sources for clinical applications