bluuebunny/crossref_metadata_2025 huggingface dataset:
NIST Ballistics Toolmark Research Database
Authors: Zheng Xiaoyu , Soons Johannes , Thompson Robert , Singh Sushama , Constantin Cerasela
Published: January 2020

In 2009, a report by the National Academies called into question, amongst other
issues, the objectivity of visual toolmark identification by firearms examiners. The
National Academies recommended development of objective toolmark identification criteria
and error rate estimates. Industry, academia, and government laboratories are pursuing
two promising approaches towards this goal: 1) development of mathematical criteria and
advanced algorithms for the objective and automated identification and scoring of
potential matches, and 2) supplementing traditional reflectance microscopy images with
three- dimensional surface topography measurement data. Development and validation of
both these approaches to objective toolmark identification are hindered by a lack of
access to toolmark data sets that 1) represent the large variety of ballistic toolmarks
encountered by toolmark examiners, and 2) represent challenging identification
scenarios, such as those posed by consecutively manufactured firearms components. The
NIST Ballistics Toolmark Research Database enables researchers to test and validate new
approaches to objective, mathematics-based, toolmark identification while easing the
transition to three- dimensional surface topography data. The database will provide a
foundation for a scientific knowledge base on the degree of similarity that can be found
between marks made by different firearms and the variability in marks made by an
individual firearm. The current, fairly limited, knowledge base is a fundamental barrier
to the development and validation of objective mathematical similarity criteria, and
associated confidence limits, applicable to a broad range of firearms and ammunition
brands.
Data Censoring with Set-Membership Affine Projection Algorithm
Authors: Karamali Gholamreza , Zardadi Akram , Moradi Hamid Reza
Published: January 2020

In this paper, the set-membership affine projection (SM-AP) algorithm is utilized to censor non-informative data in big data applications. To this end, the probability distribution of the additive noise signal and the excess of the mean-squared error (EMSE) in steady-state are employed in order to estimate the threshold parameter of the single threshold SM-AP (ST-SM-AP) algorithm aiming at attaining the desired update rate. Furthermore, by defining an acceptable range for the error signal, the double threshold SM-AP (DT-SM-AP) algorithm is proposed to detect very large errors due to the irrelevant data such as outliers. The DT-SM-AP algorithm can censor non-informative and irrelevant data in big data applications, and it can improve the misalignment and convergence rate of the learning process with high computational efficiency. The simulation and numerical results corroborate the superiority of the proposed algorithms over traditional algorithms.
Attitudes Toward Osteopathic Recognition Under the Single GME Accreditation System: A Survey of Deans at Colleges of Osteopathic Medicine and Chairs of Osteopathic Manipulative Medicine Departments
Authors: Dougherty John J. , Bray Natasha N. , Vanier Cheryl H.
Published: January 2020

Objective

To assess the attitudes of academic deans at colleges of osteopathic medicine (COMs) and chairs of COMs’ osteopathic manipulative medicine (OMM) departments toward osteopathic recognition under the single graduate medical education (GME) accreditation system.

Methods

An 11-item Likert-type survey with additional demographic questions was distributed via email to deans and OMM department chairs at 51 COMs and additional locations in September 2017. Items were formulated to assess survey participants’ understanding and beliefs regarding the value and support of the establishment of osteopathic recognition within the single GME accreditation system. Demographic information gathered was limited to role (ie, dean or OMM department chair). Survey items were ranked on a 5-point Likert-type scale from strongly disagree to strongly agree.

Results

A total of 39 COMs deans and 24 OMM chairs indicated they understood the intent of osteopathic recognition in a single GME accreditation system, but OMM chairs felt less informed about osteopathic recognition than deans (17% vs 3% disagreeing with the statement, “I have been adequately informed about osteopathic recognition”). There was no difference between deans and chairs regarding their attitudes toward osteopathic recognition in residency training programs, though a minority of deans (n=2) disagreed that osteopathic recognition benefits programs and indicated that they did not recommend it for surgical specialties (n=2) or fellowship programs (n=3). Deans and chairs generally agreed on their overall support of osteopathic recognition, the perceptions of osteopathic medical students toward osteopathic recognition, and the value that osteopathic recognition brings to COMs, with 2 deans dissenting on each item. A moderate correlation was found between information of and attitude toward osteopathic recognition for the deans (r=0.72, n=39), but a much weaker relationship was observed between information and attitude for the chairs (r=0.37, n=24) (difference between the correlations: z=1.89, P=.06).

Conclusion

Although the deans and OMM chairs agreed that they support, believe in the value of, and find that osteopathic medical students are interested in osteopathic recognition, there is an opportunity for improvement of deans’ and COMs chairs’ understanding of osteopathic recognition.
Investigating the effects of management practice on mammalian co-occurrence along the West Coast of South Africa
Authors: Winterton Deborah Jean , van Wilgen Nicola J. , Venter Jan A.
Published: January 2020

The subtle and cascading effects (e.g., altered interspecific interactions) that anthropogenic stressors have on local ecological assemblages often go unnoticed but are concerning given their importance in ecosystem function. For example, elimination of buffalo from the Serengeti National Park is suggested to have driven increased abundance of smaller antelope as a result of release from competition. The perceived low abundance of small antelope in the contractual Postberg section of the West Coast National Park (the park) has been an ongoing management concern which has been anecdotally attributed to predation by a mesopredator (the caracal, Caracal caracal). However, we hypothesized that the historical overstocking, and consequent overgrazing by larger-bodied managed ungulates would influence small antelope abundance. Using camera traps, we investigated species co-occurrence and temporal activity between small antelope, managed ungulates and caracals in Postberg as well as another part of the park (Langebaan) and a farm outside of the park. Results suggest that small antelope and managed ungulates have a high degree of temporal overlap (Δ = 0.74, 0.79 and 0.86 for the farm, Langebaan and Postberg respectively), while temporal partitioning between small antelope and caracal is apparent (Δ = 0.59). Further, small antelope and managed ungulates appear to occur independently of one another (SIF = 0.91–1 across areas). Managed ungulates were detected almost three times more frequently on fallow lands when compared to the more vegetated sites within the park suggesting that segregated food/cover resources allow for independent occurrence. Small antelope had a much higher probability of occurrence outside of the protected area (e.g., ψ = 0.192 and 0.486 for steenbok at Postberg, Langebaan compared to 0.841 on the farm), likely due to less variable (more intact) habitat outside of the protected area. There is not sufficient evidence to currently warrant management intervention for predators. The small size of the protected area provides limited scope for spatial replication thus reducing possibilities to infer the cause and effect for complex interactions (which would historically have taken place over much larger areas) with negative implications for adaptive management. We recommend continued monitoring over multiple seasons and a wider area to determine the spatial information requirements to inform management of small protected areas.
Effects of silver-graphene oxide on seed germination and early growth of crop species
Authors: Kim Min-Ji , Kim Woong , Chung Haegeun
Published: January 2020

Due to its excellent material properties, silver-graphene oxide (Ag-GO) is being studied for diverse applications, such as antimicrobial agents, catalysts and absorbents. Such use of Ag-GO may lead to its release into terrestrial ecosystems, but little is known about the impact of Ag-GO on plants. In the present study, we determined the effects of Ag-GO on seed germination and early growth of crop species by analyzing the germination rate, growth of roots and shoots, hydrogen peroxide (H2O2) accumulation, and the uptake of Ag in alfalfa, radish and cucumber treated with 0.2–1.6 mg mL−1 of Ag-GO. Ag-GO treatment increased the shoot growth of radish at 0.2–1.6 mg mL−1 but decreased that of cucumber at 0.8 mg mL−1. In addition, Ag-GO enhanced the root elongation of radish at 0.2 mg mL−1 but inhibited that of alfalfa at 0.2, 0.8 and 1.6 mg mL−1. Ag-GO treatment induced H2O2 production in alfalfa, radish and cucumber in a concentration-dependent manner. Larger amounts of Ag accumulated in the seedlings as the concentration of Ag-GO increased, and such accumulation suggests that Ag may be transferred to higher trophic levels when plants are exposed to Ag-GO in ecosystems. Our study can, thus, serve as an important basis for setting guidelines for the release of nanomaterials into the environment.
Resection vs. ablation for lesions characterized as resectable-ablative within the colorectal liver oligometastases criteria: a propensity score matching from retrospective study
Authors: Luo Ma , Chen Si-Liang , Chen Jiawen , Yan Huzheng , Qiu Zhenkang , Chen Guanyu , Lu Ligong , Zhang Fujun
Published: January 2020

Background

There has been no prospective or retrospective studies reporting the comparison outcome between surgery and ablation for resectable-ablative (lesions could be treated by resection or complete ablation) colorectal liver oligometastases (CLOM). The purpose of this study was to compare the efficacy and prognostic difference in patients who underwent R0 resection vs. complete ablation within the resectable-ablative CLOM criteria.

Methods

From January 2008 to May 2018, a total of 2,367 patients diagnosed with colorectal liver metastases were included in this observational study. The metastasis was characterized by only limited to liver with number ≤5, size ≤5 cm, and resectable-ablative (lesions could be treated by resection or complete ablation). The evaluated indications, including liver progression-free survival (LPFS), overall survival (OS), survival rates, pattern and number of recurrences, and complications, were compared by using propensity score matching (PSM). The Kaplan−Meier curves were generated, and a log-rank test was performed. The Cox regression model was used for univariate and multivariate analyses to identify predictors of outcomes.

Results

A total of 421 consecutive patients were eligible for this study, with 250 and 171 undergoing R0 resection and complete ablation, respectively. PSM identified 145 patients from each group. The 1-, 3-, 5- and 8-year OS rates in the resection group and the ablation group were 95.8% vs. 95.0%, 69.8% vs. 60.1%, 53.6% vs. 42.5%, and 45.1% vs. 32.9% (p = 0.075), respectively. The median LPFS in the resection group was significantly longer than that in the ablation group (35 months vs. 15 months, p = 0.011). No statistical difference was found in LPFS between the two groups when comparing ≤3 cm liver metastases. For liver metastasis >3 cm, the median LPFS in the resection group and ablation group was 11 months and 5 months, respectively (p = 0.001). In terms of high risk of clinical risk score (CRS), the resection group showed longer LPFS than the ablation group (median 18 months vs. 10 months, p = 0.043).

Conclusion

For patients within the CLOM criteria suggesting that liver metastases were resectable as well as ablative, resection could result in longer liver recurrence-free survival than ablation in cases with size >3 cm or high risk of CRS. But for ≤3 cm liver metastases, their treatment efficacies were comparable.
Speeding up training of automated bird recognizers by data reduction of audio features
Authors: de Oliveira Allan G. , Ventura Thiago M. , Ganchev Todor D. , Silva Lucas N.S. , Marques Marinêz I. , Schuchmann Karl-L.
Published: January 2020

Automated acoustic recognition of birds is considered an important technology in support of biodiversity monitoring and biodiversity conservation activities. These activities require processing large amounts of soundscape recordings. Typically, recordings are transformed to a number of acoustic features, and a machine learning method is used to build models and recognize the sound events of interest. The main problem is the scalability of data processing, either for developing models or for processing recordings made over long time periods. In those cases, the processing time and resources required might become prohibitive for the average user. To address this problem, we evaluated the applicability of three data reduction methods. These methods were applied to a series of acoustic feature vectors as an additional postprocessing step, which aims to reduce the computational demand during training. The experimental results obtained using Mel-frequency cepstral coefficients (MFCCs) and hidden Markov models (HMMs) support the finding that a reduction in training data by a factor of 10 does not significantly affect the recognition performance.
The diagnostic and prognostic value of UBE2T in intrahepatic cholangiocarcinoma
Authors: Yu Hua , Wang Han , Dong Wei , Cao Zhen-Ying , Li Rong , Yang Chao , Cong Wen-Ming , Dong Hui , Jin Guang-Zhi
Published: January 2020

Background

Ubiquitin-conjugating enzyme E2T (UBE2T) is overexpressed in several types of malignancies. However, little is known about its diagnostic significance in intrahepatic cholangiocarcinoma (ICC) and other bile duct diseases or its prognostic value in ICC.

Methods

The expression levels of UBE2T in the intrahepatic bile duct (IHBD, N = 13), biliary intraepithelial neoplasia (BilIN; BilIN-1/2, N = 23; BilIN-3, N = 11), and ICC (N = 401) were examined by immunohistochemistry. The differential diagnostic and prognostic values were also assessed.

Results

The number of UBE2T-positive cells was significantly higher in ICC tissues than in nonmalignant tissues, including the IHBD, BilIN-1/2, and BilIN-3 tissues. Kaplan–Meier analysis showed that overexpression of UBE2T was correlated with a shorter time to recurrence (TTR) and overall survival (OS). The 5-year TTR rates in the high UBE2T and low UBE2T groups were 100% and 86.2%, respectively. The corresponding OS rates were 1.9% and 22.2%, respectively. High expression of UBE2T was an independent risk factor for both TTR (hazard ratio: 1.345; 95% confidence interval: 1.047,1.728) and OS (hazard ratio: 1.420; 95% confidence interval: 1.098,1.837).

Conclusions

UBE2T can assist in differentiating benign bile duct diseases from ICC, and high expression of UBE2T suggests a poor prognosis for ICC.
Evaluation of three wheat (Triticum aestivum L.) cultivars as sensitive Cd biomarkers during the seedling stage
Authors: He Chuntao , Ding Zhihai , Mubeen Samavia , Guo Xuying , Fu Huiling , Xin Guorong
Published: January 2020

Sensitive seedling crops have been developed to monitor Cadmium (Cd) contamination in agricultural soil. In the present study, 18 parameters involving growth conditions and physiological performances were assessed to evaluate Cd-responses of three wheat (Triticum aestivum L.) cultivars, Xihan1 (XH), Longzhong1 (LZ) and Dingfeng16 (DF). Principle component analysis illustrated that Factor 1, representing growth performance, soluble sugar content and catalase activity, responded to the Cd treatments in a dose dependent manner, while Factor 2 represented by chlorophyll content and germinating root growth was mainly dependent on cultivar differences. Higher inhibition rates were observed in growth performance than in physiological responses, with the highest inhibition rates of shoot biomasses (39.6%), root length (58.7%), root tip number (57.8%) and bifurcation number (83.2%), even under the lowest Cd treatment (2.5 mg·L−1). According to the Cd toxicity sensitivity evaluation, DF exerted highest tolerance to Cd stress in root growth while LZ was more sensitive to Cd stress, suggesting LZ as an ideal Cd contaminant biomarker. This study will provide novel insight into the cultivar-dependent response during using wheat seedlings as Cd biomarkers.
Sequence Analysis of Plasmids in Vibrio anguillarum from Different Fish and Locations
Authors: Akter Tasmina , Lindegaard Mikkel , Pedersen Karl , Strube Mikael L. , Ronco Troels , Dalsgaard Inger
Published: January 2020

The genetic diversity of Vibrio anguillarum pJM1-like plasmids was investigated. Plasmids were isolated from 18 V. anguillarum serovar O1 strains collected from different geographic locations and fish species. The plasmids were sequenced and compared with the complete sequence of the published virulence plasmid pJM1. All 18 strains contained pJM1-like plasmids with approximately 65 kbp and all plasmids encoded the virulence genes responsible for the anguibactin iron sequestering system. The plasmids were highly conserved but minor differences were observed in some genes. A single nucleotide polymorphisms (SNPs) analysis showed 0–11 nucleotide variations between each of the 18 plasmids and the pJM1 plasmid. Compared with the sequence of pJM1, nonsynonymous SNPs were identified in fatC, angR, angL, pJM1_p19, and angE. In particular, a mutation found in 15 out of 18 sequenced plasmids in angR has previously been linked to hyperproduction of anguibactin and was found in all the European isolates. However, overall the pJM1-like plasmids isolated from V. anguillarum serovar O1 exhibited a high degree of conservation regardless of their geographical origin or fish species.
Active Reconfigurable Tristable Square‐Twist Origami
Authors: Wang Li‐Chen , Song Wei‐Li , Zhang Ya‐Jing , Qu Mei‐Jun , Zhao Zeang , Chen Mingji , Yang Yazheng , Chen Haosen , Fang Daining
Published: January 2020

Origami structures offer valuable applications in many fields, ranging from metamaterials to robotics. The multistable characteristics of origami structures have been pursued for acquiring unique reconfigurable features. For achieving this goal, an unusual polymeric tristable origami structure is demonstrated using a classic square‐twist origami configuration. By manipulating both material properties and geometric parameters of the heteropolymer structures, a design principle for tailoring the multistable configuration in the square‐twist origami is established based on variation of the structural potential energy. Under thermal triggering, the stiffness of the deformable structure is dramatically reduced, which causes an increase in the structural degree of freedom, allowing for self‐deployment via release of the prestored energy in the elastic twisted hinges. Utilizing such unique features and design principles, a prototype of frequency reconfigurable origami antenna of five diverse operating modes and a programmable multiple‐input multiple‐output communication system is subsequently designed and assembled, aiming to substantially promote the channel capacity and communication reliability. The findings and results firmly provide a remarkable design principle and strategy for advancing active origami structures and devices in shape‐morphing systems.
A Low‐Current and Analog Memristor with Ru as Mobile Species
Authors: Yoon Jung Ho , Zhang Jiaming , Lin Peng , Upadhyay Navnidhi , Yan Peng , Liu Yuzi , Xia Qiangfei , Yang J. Joshua
Published: January 2020

The switching parameters and device performance of memristors are predominately determined by their mobile species and matrix materials. Devices with oxygen or oxygen vacancies as the mobile species usually exhibit a great retention but also need a relatively high switching current (e.g., >30 µA), while devices with Ag or Cu as cation mobile species do not require a high switching current but usually show a poor retention. Here, Ru is studied as a new type of mobile species for memristors to achieve low switching current, fast speed, good reliability, scalability, and analog switching property simultaneously. An electrochemical metallization‐like memristor with a stack of Pt/Ta2O5/Ru is developed. Migration of Ru ions is revealed by energy‐dispersive X‐ray spectroscopy mapping and in situ transmission electron microscopy within a sub‐10 nm active device area before and after switching. The results open up a new avenue to engineer memristors for desired properties.
Active Metamaterials with Negative Static Electric Susceptibility
Authors: Castles Flynn , Fells Julian A. J. , Isakov Dmitry , Morris Stephen M. , Watt Andrew A. R. , Grant Patrick S.
Published: January 2020

Although well‐established textbook arguments suggest that static electric susceptibility χ(0) must be positive in “all bodies,” it has been pointed out that materials that are not in thermodynamic equilibrium are not necessarily subject to this restriction. Media with inverted populations of atomic and molecular energy levels have been predicted theoretically to exhibit a χ(0) < 0 state, however the systems envisioned require reduced temperature, reduced pressure, and an external pump laser to maintain the population inversion. Further, the existence of χ(0) < 0 has never been confirmed experimentally. Here, a completely different approach is taken to the question of χ(0) < 0 and a design concept to achieve “true” χ(0) < 0 is proposed based on active metamaterials with internal power sources. Two active metamaterial structures are fabricated that, despite still having their power sources implemented externally for reasons of practical convenience, provide evidence in support of the general concept. Effective values are readily achieved at room temperature and pressure and are tunable throughout the range of stability −1 < χ(0) < 0, resulting in experimentally‐determined magnitudes that are over one thousand times greater than those predicted previously. Since χ(0) < 0 is the missing electric analog of diamagnetism, this work opens the door to new technological capabilities such as stable electrostatic levitation.
A Single‐Ion Conducting Borate Network Polymer as a Viable Quasi‐Solid Electrolyte for Lithium Metal Batteries
Authors: Shin Dong‐Myeong , Bachman Jonathan E. , Taylor Mercedes K. , Kamcev Jovan , Park Jesse G. , Ziebel Michael E. , Velasquez Ever , Jarenwattananon Nanette N. , Sethi Gurmukh K. , Cui Yi , Long Jeffrey R.
Published: January 2020

Lithium‐ion batteries have remained a state‐of‐the‐art electrochemical energy storage technology for decades now, but their energy densities are limited by electrode materials and conventional liquid electrolytes can pose significant safety concerns. Lithium metal batteries featuring Li metal anodes, solid polymer electrolytes, and high‐voltage cathodes represent promising candidates for next‐generation devices exhibiting improved power and safety, but such solid polymer electrolytes generally do not exhibit the required excellent electrochemical properties and thermal stability in tandem. Here, an interpenetrating network polymer with weakly coordinating anion nodes that functions as a high‐performing single‐ion conducting electrolyte in the presence of minimal plasticizer, with a wide electrochemical stability window, a high room‐temperature conductivity of 1.5 × 10−4 S cm−1, and exceptional selectivity for Li‐ion conduction (tLi+ = 0.95) is reported. Importantly, this material is also flame retardant and highly stable in contact with lithium metal. Significantly, a lithium metal battery prototype containing this quasi‐solid electrolyte is shown to outperform a conventional battery featuring a polymer electrolyte.
Retina‐Inspired Carbon Nitride‐Based Photonic Synapses for Selective Detection of UV Light
Authors: Park Hea‐Lim , Kim Haeju , Lim Donggyu , Zhou Huanyu , Kim Young‐Hoon , Lee Yeongjun , Park Sungjin , Lee Tae‐Woo
Published: January 2020

Photonic synapses combine sensing and processing in a single device, so they are promising candidates to emulate visual perception of a biological retina. However, photonic synapses with wavelength selectivity, which is a key property for visual perception, have not been developed so far. Herein, organic photonic synapses that selectively detect UV rays and process various optical stimuli are presented. The photonic synapses use carbon nitride (C3N4) as an UV‐responsive floating‐gate layer in transistor geometry. C3N4 nanodots dominantly absorb UV light; this trait is the basis of UV selectivity in these photonic synapses. The presented devices consume only 18.06 fJ per synaptic event, which is comparable to the energy consumption of biological synapses. Furthermore, in situ modulation of exposure to UV light is demonstrated by integrating the devices with UV transmittance modulators. These smart systems can be further developed to combine detection and dose‐calculation to determine how and when to decrease UV transmittance for preventive health care.
Achieving Efficient Alkaline Hydrogen Evolution Reaction over a Ni5P4 Catalyst Incorporating Single‐Atomic Ru Sites
Authors: He Qun , Tian Dong , Jiang Hongliang , Cao Dengfeng , Wei Shiqiang , Liu Daobin , Song Pin , Lin Yue , Song Li
Published: January 2020

Developing efficient electrocatalysts for alkaline water electrolysis is central to substantial progress of alkaline hydrogen production. Herein, a Ni5P4 electrocatalyst incorporating single‐atom Ru (Ni5P4‐Ru) is synthesized through the filling of Ru3+ species into the metal vacancies of nickel hydroxides and subsequent phosphorization treatment. Electron paramagnetic resonance spectroscopy, X‐ray‐based measurements, and electron microscopy observations confirm the strong interaction between the nickel‐vacancy defect and Ru cation, resulting in more than 3.83 wt% single‐atom Ru incorporation in the obtained Ni5P4‐Ru. The Ni5P4‐Ru as an alkaline hydrogen evolution reaction catalyst achieves low onset potential of 17 mV and an overpotential of 54 mV at a current density of 10 mA cm‐2 together with a small Tafel slope of 52.0 mV decade‐1 and long‐term stability. Further spectroscopy analyses combined with density functional theory calculations reveal that the doped Ru sites can cause localized structure polarization, which brings the low energy barrier for water dissociation on Ru site and the optimized hydrogen adsorption free energy on the interstitial site, well rationalizing the experimental reactivity.
The Rise of 2D Photothermal Materials beyond Graphene for Clean Water Production
Authors: Xie Zhongjian , Duo Yanhong , Lin Zhitao , Fan Taojian , Xing Chenyang , Yu Li , Wang Renheng , Qiu Meng , Zhang Yupeng , Zhao Yonghua , Yan Xiaobing , Zhang Han
Published: January 2020

Water shortage is one of the most concerning global challenges in the 21st century. Solar‐inspired vaporization employing photothermal nanomaterials is considered to be a feasible and green technology for addressing the water challenge by virtue of abundant and clean solar energy. 2D nanomaterials aroused considerable attention in photothermal evaporation‐induced water production owing to their large absorption surface, strong absorption in broadband solar spectrum, and efficient photothermal conversion. Herein, the recent progress of 2D nanomaterials‐based photothermal evaporation, mainly including emerging Xenes (phosphorene, antimonene, tellurene, and borophene) and binary‐enes (MXenes and transition metal dichalcogenides), is reviewed. Then, the optimization strategies for higher evaporation performance are summarized in terms of modulation of the intrinsic photothermal performance of 2D nanomaterials and design of the complete evaporation system. Finally, the challenges and prospective of various kinds of 2D photothermal nanomaterials are discussed in terms of the photothermal performance, stability, environmental influence, and cost. One important principle is that solutions for water challenges should not introduce new environmental and social problems. This Review aims to highlight the role of 2D photothermal nanomaterials in solving water challenges and provides a viable scheme toward the practical use in photothermal materials selection, design, and evaporation systems building.
Pressure‐Induced Structural Evolution and Bandgap Optimization of Lead‐Free Halide Double Perovskite (NH4)2SeBr6
Authors: Wang Lingrui , Yao Panpan , Wang Fei , Li Shunfang , Chen Yaping , Xia Tianyu , Guo Erjia , Wang Kai , Zou Bo , Guo Haizhong
Published: January 2020

Lead‐free halide double perovskites (HDPs) are promising candidates for high‐performance solar cells because of their environmentally‐friendly property and chemical stability in air. The power conversion efficiency of HDPs‐based solar cells needs to be further improved before their commercialization in the market. It requires a thoughtful understanding of the correlation between their specific structure and property. Here, the structural and optical properties of an important HDP‐based (NH4)2SeBr6 are investigated under high pressure. A dramatic piezochromism is found with the increase in pressure. Optical absorption spectra reveal the pressure‐induced red‐shift in bandgap with two distinct anomalies at 6.57 and 11.18 GPa, and the energy tunability reaches 360 meV within 20.02 GPa. Combined with structural characterizations, Raman and infrared spectra, and theoretical calculations using density functional theory, results reveal that, the first anomaly is caused by the formation of a Br‐Br bond among the [SeBr6]2− octahedra, and the latter is attributed to a cubic‐to‐tetragonal phase transition. These results provide a clear correlation between the chemical bonding and optical properties of (NH4)2SeBr6. It is believed that the proposed strategy paves the way to optimize the optoelectronic properties of HDPs and further stimulate the development of next‐generation clear energy based on HDPs solar cells.
Strain–Chemical Gradient and Polarization in Metal Halide Perovskites
Authors: Liu Yongtao , Ievlev Anton V. , Collins Liam , Belianinov Alex , Keum Jong K. , Ahmadi Mahshid , Jesse Stephen , Retterer Scott T. , Xiao Kai , Huang Jingsong , Sumpter Bobby G. , Kalinin Sergei V. , Hu Bin , Ovchinnikova Olga S.
Published: January 2020

Metal halide perovskites (MHPs) have attracted broad research interest due to their outstanding optoelectronic performance. This performance has been attributed in part to the presence of polarization in these materials. However, the precise effects of chemical environment and strain condition on the polar states in MHPs have largely been missing. It is revealed for the first time that chemical gradient is directly coupled with strain gradient in CH3NH3PbI3. This strain–chemical gradient induces an electric polarization that can potentially affect charge carrier dynamics. Furthermore, it is unveiled that this electric polarization—unlike ferroelectricity that only exists in noncentrosymmetric materials—can be present in both tetragonal and cubic phases of CH3NH3PbI3. This suggests that the strain–chemical gradient induced polarization is a more convincing explanation of the outstanding photovoltaic properties of MHPs than the hotly debated ferroelectric polarization. Finally, a mechanism of how this polarization impacts photovoltaic action is proposed, which offers insightful advances in the development of MHPs.
Transition Metal‐Mediated C−C Single Bond Cleavage: Making the Cut in Total Synthesis
Authors: Wang Brian , Perea Melecio A. , Sarpong Richmond
Published: January 2020

Transition‐metal‐mediated cleavage of C−C single bonds can enable entirely new retrosynthetic disconnections in the total synthesis of natural products. Given that C−C bond cleavage inherently alters the carbon framework of a compound, and that, under transition‐metal catalysis, the generated organometallic or radical intermediate is primed for further complexity‐building reactivity, C−C bond‐cleavage events have the potential to drastically and rapidly remodel skeletal frameworks. The recent acceleration of the use of transition‐metal‐mediated cleavage of C−C single bonds in total synthesis can be ascribed to a communal recognition of this fact. In this Review, we highlight ten selected total syntheses from 2014 to 2019 that illustrate how transition‐metal‐mediated cleavage of C−C single bonds at either the core or the periphery of synthetic intermediates can streamline synthetic efforts.
Total Synthesis of Tetrodotoxin
Authors: Murakami Keigo , Toma Tatsuya , Fukuyama Tohru , Yokoshima Satoshi
Published: January 2020

A total synthesis of tetrodotoxin was accomplished. A Diels–Alder reaction between a known enone and a siloxy diene gave a tricyclic product, the steric bias of which was used to construct the remaining stereogenic centers. A nitrogen atom was introduced either by a four‐step sequence involving a Curtius rearrangement, or a three‐step sequence featuring a newly developed transformation of a terminal alkyne into a nitrile. Introduction of the guanidine moiety followed by the formation of the heterocyclic system by cascade reactions led to tetrodotoxin.
Surface Reorganization on Electrochemically‐Induced Zn–Ni–Co Spinel Oxides for Enhanced Oxygen Electrocatalysis
Authors: Wang Xiao‐Tong , Ouyang Ting , Wang Ling , Zhong Jia‐Huan , Liu Zhao‐Qing
Published: January 2020

Herein, we highlight redox‐inert Zn2+ in spinel‐type oxide (ZnXNi1−XCo2O4) to synergistically optimize physical pore structure and increase the formation of active species on the catalyst surface. The presence of Zn2+ segregation has been identified experimentally and theoretically under oxygen‐evolving condition, the newly formed VZn−O−Co allows more suitable binding interaction between the active center Co and the oxygenated species, resulting in superior ORR performance. Moreover, a liquid flow Zn–air battery is constituted employing the structurally optimized Zn0.4Ni0.6Co2O4 nanoparticles supported on N‐doped carbon nanotube (ZNCO/NCNTs) as an efficient air cathode, which presents remarkable power density (109.1 mW cm−2), high open circuit potential (1.48 V vs. Zn), excellent durability, and high‐rate performance. This finding could elucidate the experimentally observed enhancement in the ORR activity of ZnXNi1−XCo2O4 oxides after the OER test.
Heart‐Cut Two‐Dimensional Countercurrent Chromatography for the Isolation of a Furan Fatty Acid Triacylglycerol from Latex Gloves and Identification of Further Lipid Compounds
Authors: Wiedmaier‐Czerny Nina , Müller Marco , Vetter Walter
Published: January 2020

Hevea brasiliensis latex from specific genotypes such as RRIM501 or PB235 is one of the richest natural sources of furan fatty acid 9‐(3‐methyl‐5‐pentylfuran‐2‐yl)‐nonanoic acid (9M5), which is mainly present in the form of triacylglycerols. In this study, we successfully isolated a triacylglycerol esterified with three 9M5 molecules (tri‐9M5) with a purity of 97% from the lipid extract of latex gloves by means of countercurrent chromatography (CCC). The gas chromatography with a mass spectrometry (GC/MS) spectrum of tri‐9M5 not only featured the diagnostic fragment ion [M‐RCOO]+ of triacylglycerols but also a fragment ion shifted by 16 Da to higher mass which corresponded with [M‐RCO]+. [M‐RCO]+ was only detected in triacylglycerols substituted with at least one furan fatty acid. Additionally, five γ‐tocotrienyl fatty acid esters (γ‐T3‐FA esters), namely, γ‐T3‐16:0, γ‐T3‐18:0, γ‐T3‐18:1n‐9, γ‐T3‐18:2n‐6 and γ‐T3‐20:0, were detected in the sample. Contributions of γ‐T3‐FA esters with 18:1n‐9 and 18:2n‐6 which co‐eluted in GC/MS could be calculated after mathematical correction for contributions of the 13C2 isotope peak of γ‐T3‐18:2n‐6 to γ‐T3‐18:1n‐9. This was necessary for quantitation of these two γ‐T3‐FA esters. Improved separation of the γ‐T3‐FA esters could be achieved by the novel heart‐cut recycling CCC mode (four cycles). Sterols detected in disposable latex gloves were β‐sitosterol, Δ5‐avenasterol, and stigmasterol along with small quantities of 24‐methylene‐cycloartenol and Δ5‐citrostadienol.
Effect of different PVDF and additives on the properties of hollow fiber membranes contactors for CO2 separation
Authors: Pereira Cristina Cardoso , Nascimento Jailton Ferreira , Grava Wilson Mantovani , Borges Cristiano Piacsek
Published: January 2020

In the present work, different poly(vinil fluoride) (PVDF) were selected for preparing membranes, based on the fact that they are able to form polymer solutions with different viscosities. This characteristic can affect spinning, as well as, mass transfer between the polymer solution and precipitation bath; therefore, each PVDF solution can differently affect membrane formation. The effect of different additives in the polymer solutions was also investigated. Flat sheet and hollow fiber membranes were characterized by Scanning Electron Microscopy analysis, contact angle, gas permeation, porosity, and membrane gas–liquid contactor tests, aiming carbon dioxide removal. The hollow fibers prepared by the polymer which formed a less viscous solution (named PVDF‐I) had a faster light transmittance decay, which started around 150 s before the more viscous solution (PVDF‐II). Hollow fibers obtained using PVDF‐I and propionic acid, in the polymer solution, presented the best gas–liquid contactor performance. CO2 removal increased from 21 to 35.1%, for PVDF‐II and PVDF‐I, respectively, using aqueous diethanolamine solution, as absorbent liquid. In conclusion, even though PVDF‐I and PVDF‐II membranes were obtained by using the same spinning conditions and experimental methodology, the difference between the polymers properties certainly affected the final membrane morphology and transport properties.
Isatin dimers and their biological activities
Authors: Zhang Ya‐Zhou , Du Hong‐Zhi , Liu Hai‐Lin , He Qian‐Song , Xu Zhi
Published: January 2020

Dimerization is a promising strategy to develop novel drug candidates that could extend the biological spectrum, enhance the activity, overcome drug resistance, as well as improve pharmacological, pharmacokinetic, and physicochemical profiles. Isatin dimers possess a broad spectrum of biological properties and the isatin dimer indirubin has already been used in the clinic, revealing the potential of isatin dimers as putative drugs. This review covers the recent advances of isatin dimers as pharmacologically significant scaffolds and the structure–activity relationship to set up the direction for the design and development of isatin dimers with higher efficiency and lower toxicity.
Social optima in linear quadratic mean field control with unmodeled dynamics and multiplicative noise
Authors: Wang Bing‐Chang , Yu Xin , Dong Hailing
Published: January 2020

This paper investigates the linear‐quadratic social control problem for mean field systems with unmodeled dynamics and multiplicative noise. The objective of each agent is to optimize the social cost in the worst‐case disturbance. We first analyze the centralized strategies by the person‐by‐person optimality and then construct an auxiliary zero‐sum game according to mean field approximations. By solving the auxiliary problem subject to consistency conditions, we design a set of decentralized strategies, which is further shown to have asymptotic robust social optimality.
Availability, procurement, training, usage, maintenance and complications of electrosurgical units and laparoscopic equipment in 12 African countries
Authors: Oosting R M , Wauben L S G L , Madete J K , Groen R S , Dankelman J
Published: January 2020

Background

Strategies are needed to increase the availability of surgical equipment in low- and middle-income countries (LMICs). This study was undertaken to explore the current availability, procurement, training, usage, maintenance and complications encountered during use of electrosurgical units (ESUs) and laparoscopic equipment.

Methods

A survey was conducted among surgeons attending the annual meeting of the College of Surgeons of East, Central and Southern Africa (COSECSA) in December 2017 and the annual meeting of the Surgical Society of Kenya (SSK) in March 2018. Biomedical equipment technicians (BMETs) were surveyed and maintenance records collected in Kenya between February and March 2018.

Results

Among 80 participants, there were 59 surgeons from 12 African countries and 21 BMETs from Kenya. Thirty-six maintenance records were collected. ESUs were available for all COSECSA and SSK surgeons, but only 49 per cent (29 of 59) had access to working laparoscopic equipment. Reuse of disposable ESU accessories and difficulties obtaining carbon dioxide were identified. More than three-quarters of surgeons (79 per cent) indicated that maintenance of ESUs was available, but only 59 per cent (16 of 27) confirmed maintenance of laparoscopic equipment at their centre.

Conclusion

Despite the availability of surgical equipment, significant gaps in access to maintenance were apparent in these LMICs, limiting implementation of open and laparoscopic surgery.
Serum Midkine is a clinical significant biomarker for colorectal cancer and associated with poor survival
Authors: Kemper Marius , Hentschel Wiebke , Graß Julia‐Kristin , Stüben Bjoern‐Ole , Konczalla Leonie , Rawnaq Tamina , Ghadban Tarik , Izbicki Jakob R. , Reeh Matthias
Published: January 2020

Colorectal carcinoma (CRC) is one of the most common carcinomas worldwide. Early detection is crucial for reducing morbidity and mortality. Several promising studies described the use of midkine (MK) as a tumor marker. This study aimed to investigate a larger collective to ascertain if the preoperative serum midkine level (S‐MK) is suitable as a marker for screening and if S‐MK correlates with tumor progression and localization. It was also investigated for the first time whether patients with high S‐MK show poor survival. This prospective single‐center study included 299 patients with CRC. The preoperative serum midkine level (S‐MK) was determined using ELISA. Established tumor markers Carcinoembryonic antigen (CEA) and Carbohydrate antigen 19‐9 (CA 19‐9) were collected for comparison. The median follow‐up period was 65 months. S‐MK was significantly elevated in patients with CRC (P < .001). The receiver operation characteristic (ROC) curve has an area under the curve (AUC) of 0.868 (P < .001). A cut‐off value of 56.42 pg/mL results in a sensitivity of 84.3% and a specificity of 75.4%. In the one‐way analysis of variance (ANOVA), there were no significant correlations between S‐MK and tumor progression, localization. Furthermore, no significant correlation to CEA und CA 19‐9 could be found. Kaplan‐Meier survival analysis was able to show for the first time that patients with S‐MK of more than 225 pg/mL have a significantly shorter survival. Multivariate Cox regression showed that only CEA was an independent prognostic factor for survival. S‐MK helps estimate the prognosis for CRC and is a valuable component for developing a multimarker panel for screening and surveillance.
Reporter‐Guided Transposon Mutant Selection for Activation of Silent Gene Clusters in Burkholderia thailandensis
Authors: Mao Dainan , Yoshimura Aya , Wang Rurun , Seyedsayamdost Mohammad R.
Published: January 2020

Most natural product biosynthetic gene clusters that can be observed bioinformatically are silent. This insight has prompted the development of several methodologies for inducing their expression. One of the more recent methods, termed reporter‐guided mutant selection (RGMS), entails creation of a library of mutants that is then screened for the desired phenotype via reporter gene expression. Herein, we apply a similar approach to Burkholderia thailandensis and, using transposon mutagenesis, mutagenize three strains, each carrying a fluorescent reporter in the malleilactone (mal), capistruin (cap), or an unidentified ribosomal peptide (tomm) gene cluster. We show that even a small library of <500 mutants can be used to induce expression of each cluster. We also explore the mechanism of activation and find that inhibition of pyrimidine biosynthesis is linked to the induction of the mal cluster. Both a transposon insertion into pyrF as well as small‐molecule‐mediated inhibition of PyrF trigger malleilactone biosynthesis. Our results pave the way toward the broad application of RGMS and related approaches to Burkholderia spp.
STA‐55, an Easily Accessible, Broad‐Spectrum, Activity‐Based Aldehyde Dehydrogenase Probe
Authors: Koenders Sebastiaan T. A. , van Rooden Eva J. , van den Elst Hans , Florea Bogdan I. , Overkleeft Herman S. , van der Stelt Mario
Published: January 2020

Aldehyde dehydrogenases (ALDHs) convert aldehydes into carboxylic acids and are often upregulated in cancer. They have been linked to therapy resistance and are therefore potential therapeutic targets. However, only a few selective and potent inhibitors are currently available for this group of enzymes. Competitive activity‐based protein profiling (ABPP) would aid the development and validation of new selective inhibitors. Herein, a broad‐spectrum activity‐based probe that reports on several ALDHs is presented. This probe was used in a competitive ABPP protocol against three ALDH inhibitors in lung cancer cells to determine their selectivity profiles and establish their target engagement.
Feasibility and safety of orbital atherectomy for the treatment of in‐stent restenosis secondary to stent under‐expansion
Authors: Neupane Saroj , Basir Mir , Tan Christina , Sultan Adnan , Tabaku Mishel , Alqarqaz Mohammad , Khandelwal Akshay , Gupta Ankur , Don Creighton , Alaswad Khaldoon
Published: January 2020

Background

Debulking and ablative techniques are sometimes used for the treatment of in‐stent restenosis (ISR) secondary to resistant stent under‐expansion (SU). The safety and effectiveness of orbital atherectomy (OA) in this cohort of patients has not been reported.

Methods

We retrospectively evaluated consecutive patients treated with OA for ISR secondary to balloon undilatable SU at two academic tertiary care centers between October 2016 and June 2019. Angiographic or intravascular imaging identified SU. Technical success was defined as residual 0% stenosis with TIMI III flow.

Results

A total of 41 patients were included in the study. Patients had an average age of 65 ± 12 years; 73% male, 61% diabetic, 41% with prior coronary artery bypass grafting, 61% with a prior incident of ISR, 51% presented with stable angina, 17% unstable angina, and 32% non‐ST elevation myocardial infarction (MI). Implantation of the under‐expanded stents occurred between 2 months and 22 years prior to the index procedure. A total of 27% of patients had multiple layers of stents in the target lesion and 32% of patients had in‐stent chronic total occlusion. Technical success was achieved in 40 (98%) patients. There were 2 (5%) major adverse cardiovascular events; both of them were periprocedural MI from the no‐reflow phenomenon. There were 2 (5%) Ellis type II coronary perforations that required no intervention.

Conclusions

OA can be effectively performed as an adjunctive tool in the treatment of ISR with balloon undilatable SU. The use of OA for SU is not approved by the U.S. Food and Drug Administration and is “off label” and caution must be used to limit any device/stent interaction.