bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on the Application of Prefabricated Buildings in Infrastructure Projects of University in the Western Region
Authors: Wenqiang Dang
Published: June 2021

At present, prefabricated buildings are in a period of rapid development in my country, and ordinary colleges and universities are also in a stage of rapid development striving for world-class. Infrastructure construction is a strong guarantee for the development of universities, and the scale of construction is increasing every year. Taking advantage of the leading role of universities in the application of cutting-edge technology, researching the promotion of prefabricated buildings in basic construction projects in universities not only conforms to the development concept of green campuses, but also promotes the wide application of prefabricated buildings, which has a strong demonstration effect.
Root morphological, Cd accumulation and tolerance characteristics of 2 Dianthus caryophyllus cultivars under Cd stress
Authors: Wu Jiong , Ke Changdi , Zu Yanqun , Din Yu , Li Taiting
Published: June 2021

For studying the physiological response of two different Dianthus caryophyllus cultivars on Cd stress, pot experiment was carried out to measure proline and glutathione in leaves, five types of organic acids in root exudates (oxalic acid, malic acid, acetic acid, tartaric acid, citric acid), soluble sugars and free amino acids, root length, root surface area, root volume, root projected area and Cadmium content in soil, plant roots and aboveground. According to the effects of cadmium stress on the physiological and biochemical characteristics of two Dianthus caryophyllus, the results showed that: the growth of two cultivars are affected, “Master” and “Xiao Yan” are manifested as plant height, leaf, flower buds and biomass decreased, but the “Master” by the stronger inhibitory effect. The root length, total root surface area, total root projected area, and average root diameter of the “Master” increased under cadmium stress, but the root volume decreased. However, the root length, total root surface area, root volume, and root projected area of the “Xiao Yan” under cadmium stress decreased, while the average root diameter increased. The glutathione in the leaves of the two cultivars decreased, the proline content of the leaves of the “Xiao Yan” increased, while that of the “Master” decreased. In the root exudates, the free amino acid content of the two cultivars are reduced, and the secretion of organic acids is also inhibited (except for the citric acid secreted in the “Master”), while the soluble sugar content in the root exudates is expressed as “Xiao Yan” increased, and the “Master” decreased. According to the physiological response to the two cultivars under cadmium stress, the “Xiao Yan” is more suitable for soil restoration in the mining area of Lanping area.
A Study on Improving ESP English Reading Ability for Students Major in Mechanical Design and Manufacturing
Authors: Du Juan
Published: June 2021

ESP Teaching method is an approach that is significantly different from the conventional English Language Teaching method. ESP teaching is a market-driven, communicative English teaching model which is based on the overall principle of significantly improving learners' professional English social skills, learnercentered, and meets the needs of society and individuals. In this study, researcher’s attempt is to integrate ESP reading model into the design and manufacturing English teaching. The study aims to explores the effect of ESP reading in mechanical design and manufacturing English teaching from the following three points, preclass reading task detection, while-reading teaching and post-reading teaching. And the author finds that ESP reading model not only make students have a strong interest in English learning and reading, improve their English reading ability and application ability of professional knowledge, but also enhance their innovative thinking ability.
Research progress of chiral ligand exchange stationary phases in the enantiomer resolution
Authors: Bai Hui
Published: June 2021

The structure of chiral drugs contains at least one asymmetric center. When the enantiomers act on the human body, they are recognized by chiral receptors and enzymes in vivo, which will show different physiological effects and even adverse reactions. Therefore, it is very important for the development of chiral pharmacy to obtain chiral enantiomers with a single configuration by racemic resolution. Some general impurities will be introduced in the production of chiral drugs, thus the detection of impurities is also a crucial step in the quality control of chiral medicines. The chiral ligand exchange stationary phase has a strong recognition effect on enantiomer analytes with multiple chelating sites, and is very suitable for the separation and control of biological samples such as amino acids. In this work, the development of chiral ligand exchange stationary phases in enantiomeric resolution is reviewed, which is expected to provide a basis for the quality control of complex chiral drug components.
Simulation of Optical Coherence Elastography in Agar Based on Finite Element Analysis
Authors: Tao Xingming , Fang Lihua , Lin Luchao , Du Ruirui , Song Yinyu
Published: June 2021

The finite element method is used to simulate the optical coherent elastic imaging in Agar. The shear wave velocity in Agar was measured by ARF-OCE system, and then the Agar model was established by finite element method, and then the shear wave velocity in Agar model was measured. The shear wave velocity in experiment and finite element simulation were compared and analyzed. The shear wave velocity obtained in the experiment is 2.50 m/s, and the range of shear wave velocity obtained in the finite element simulation is 2.4802m/s, and the average wave velocity is 2.5167m/s. The finite element method can express tissue elasticity directly and clearly, and it plays a great guiding role in corneal elastography.
Extraction and analysis of chemical constituents from mangosteen pericarp
Authors: Liu Hua , He Rong , Zheng Liwen , Xie Shuyao
Published: June 2021

In order to improve the utilization efficiency of mangosteen pericarp and make rational use of its active components, the antibacterial, anti-inflammatory and anti-tumor active components, molecular formula, structural formula, physical and chemical properties and action mechanism of mangosteen pericarp were analyzed The results showed that the active components of mangosteen shell also had antioxidant activity, anti-ultraviolet radiation effect, cardiovascular disease improvement effect, neuroprotective effect and intestinal disease protection effect. Among the extraction methods of active components from mangosteen shell, supercritical fluid extraction and vegetable oil assisted extraction have the characteristics of green nature, environmental protection and energy saving, and have broad market prospects in the development and utilization of mangosteen pericarp.
A disposable DNA methylation sensor based on the printable graphene field effect transistor
Authors: Jia Yunfang , Zhang Jizhao , Fan Qingjie
Published: June 2021

The detection of DNA methylation is necessary for the research of epigenetics. In this work we would like to propose a disposable DNA methylation sensor by using graphene field effect transistor (GFET) as the sensing platform. In this component, the liquid-phase exfoliated graphene (LEG) nanosheets were drop-coated on the flexible substrates of polyethylene terephthalate (PET) films. Then, the interdigital structured electrodes (named as source and drain) were printed on the LEG coated PET films to form the expected GFETs. Thirdly, the carbon dots (CDs) decoration was conducted and examined on the asprepared GFETs to evaluate the influence of CDs, as well as optimize CDs’ concentration. At last, the immune identification-based sensing strategy was utilized on the CDs modified GFETs to develop the concerned DNA methylation sensor. The experimental data indicate the proposed sensors could be a potential experimental tool for epigenetic research.
Analysis of Peripherally Inserted Central Catheter Line in Cancer Patients: A Single-Center Experience
Authors: Sapkota Sulav , Sannur Raju , Naik Radheshyam
Published: June 2021

Background Peripherally inserted central venous catheters are now widely used in cancer patients who require long-term treatment, for delivering multiple infusates. We aimed to evaluate the overall use of peripherally inserted central catheter (PICC) line in cancer patients, with the objective to study the demographic profile, complications, and safety related to PICC line in cancer patients.

Methods All the patients undergoing treatment for hematological and solid malignancies with PICC line inserted at the Healthcare Global Hospital during the study were evaluated prospectively. The complications related to PICC and its safety were analyzed.

Results Five hundred PICCs were inserted over a period of 2 years to 8 months for a total of 62,440 catheter days (mean of 24 days, i.e., 4.2 months, range: 1–434 days). The most common indication for PICC was for delivering chemotherapy (100%). Of these, 51 (10.2%) PICCs had complications at the rate of 0.82/1000 PICC days, and hence, 41 PICCs were removed. Hematological malignancies had more complications as compared with those with solid malignancies.

Conclusions PICCs are comparatively safe method for the central venous access in cancer patients.
Minimally Invasive Esophagectomy in Semi-Prone Position (Pawar Technique): Technical Aspects and Outcome in 224 Patients
Authors: Pawar Suraj B. , Bagul Kiran G. , Anap Yogesh S. , Tanawade Prasad K. , Mane Ashwini , Patil Snehdeep S. , Pawar Reshma S. , Kulkarni Shubham S. , Pawar Aditya S.
Published: June 2021

Background and Objectives There are two patient positions described for minimally invasive esophagectomy (MIE) for esophageal cancer, viz., left lateral and prone positions. To retain the benefits and overcome the disadvantages of these positions, a semi-prone position was developed by us. Our objective was to analyze the feasibility of performing MIE in this position.

Materials and Methods A retrospective review of patients who underwent MIE at our center from January 2007 to December 2017 was done. A semi-prone position is a left lateral position with an anterior inclination of 45 degrees. Intraoperative parameters including conversion rate, immediate postoperative outcomes, and long-term oncological outcomes were analyzed.

Statistical Analysis Statistical Package for the Social Sciences version 19 (IBM SPSS, IBM Corp., Armonk, New York, United States) was utilized for analysis. Survival analysis was done using Kaplan-Meier graph. Quantitative data were described as mean or median with standard deviation, and qualitative data were described as frequency distribution tables.

Results Consecutive 224 patients with good performance status were included. After excluding those who required conversion (14 [6.6%]), 210 patients were further analyzed. Median age was 60 years (range: 27–80 years). Neoadjuvant treatment recipients were 160 (76%) patients. Most common presentation was squamous cell carcinoma (146 [70%]) of lower third esophagus (140 [67%]) of stage III (126 [60%]). Median blood loss for thoracoscopic dissection and for total operation was 101.5 mL (range: 30–180 mL) and 286 mL (range: 93–480 mL), respectively. Median operative time for thoracoscopic dissection alone was 67 minutes (range: 34–98 minutes) and for entire procedure was 215 minutes (range: 162–268 minutes). There was no intraoperative mortality. Median 16 lymph nodes were dissected (range: 5–32). Postoperative complication rate and mortality was 50% and 3.3%, respectively. Disease-free interval was 18 months (range: 3–108 months) and overall survival was 22 months (range: 6–108 months).

Conclusion MIE with mediastinal lymphadenectomy in a semi-prone position is feasible, convenient, oncologically safe, which can combine the benefits of the two conventional approaches. Further prospective and comparative studies are required to support our findings.
Temporary Extrathoracic Vacuum Therapy Splint in Chest Wall Reconstruction
Authors: Vasudevan Srikanth , Vaidya Shriram , S. Ritu Baath , C. Ashok Basur , N. Anantheswar Yellambalase , Nagireddy Sudarshan Reddy
Published: June 2021

Background Paradoxical respiration is a sinister consequence of bony chest cage defects which can persist even post chest wall reconstruction. It leads to prolonged dependence on mechanical ventilation postoperatively, thereby delaying recovery. Methods Negative pressure wound therapy (NPWT) was applied in early postoperative period to a patient with chest wall defect reconstructed with folded prolene mesh and free anterolateral thigh flap. Arterial blood gas (ABG), fraction of inspired oxygen (FiO2), peak end expiratory pressure (PEEP), oxygen saturation (SpO2), and blood pressure (BP) readings pre and post NPWT application were compared. Results There was marked improvement in the breathing mechanics and related parameters post NPWT application over the flap. Conclusions Negative extrathoracic pressure in the form of a temporary splint can enable early weaning off the ventilator and a smoother postoperative recovery in reconstructed chest wall defects.
Current and Evolving Indications for Simultaneous Liver Kidney Transplantation
Authors: Nilles Kathy M. , Levitsky Josh
Published: June 2021

This review will discuss the etiologies of kidney disease in liver transplant candidates, provide a historical background of the prior evolution of simultaneous liver–kidney (SLK) transplant indications, discuss the current indications for SLK including Organ Procurement and Transplantation Network policies and Model for End Stage Liver Disease exception points, as well as provide an overview of the safety net kidney transplant policy. Finally, the authors explore unanswered questions and future research needed in SLK transplantation.
Drug-Induced Vanishing Bile Duct Syndrome: From Pathogenesis to Diagnosis and Therapeutics
Authors: Bessone Fernando , Hernández Nelia , Tanno Mario , Roma Marcelo G.
Published: June 2021

The most concerned issue in the context of drug/herb-induced chronic cholestasis is vanishing bile duct syndrome. The progressive destruction of intrahepatic bile ducts leading to ductopenia is usually not dose dependent, and has a delayed onset that should be suspected when abnormal serum cholestasis enzyme levels persist despite drug withdrawal. Immune-mediated cholangiocyte injury, direct cholangiocyte damage by drugs or their metabolites once in bile, and sustained exposure to toxic bile salts when biliary epithelium protective defenses are impaired are the main mechanisms of cholangiolar damage. Current therapeutic alternatives are scarce and have not shown consistent beneficial effects so far. This review will summarize the current literature on the main diagnostic tools of ductopenia and its histological features, and the differential diagnostic with other ductopenic diseases. In addition, pathomechanisms will be addressed, as well as the connection between them and the supportive and curative strategies for ductopenia management.
Clinical Factors of High-Flow Nasal Cannula Oxygen Success in Children
Authors: Iplik Gokce , Yildizdas Dincer , Yontem Ahmet
Published: June 2021

This study was aimed to evaluate the success rate of high-flow nasal cannula (HFNC) oxygen therapy and factors causing therapy failure. This prospective observational study included 131 children who received HFNC oxygen and followed-up in the pediatric emergency department, pediatric clinics, and pediatric intensive care unit between March 2018 and December 2019. The median age was 23.0 months (interquartile range [IQR]: 9.0–92.0) and 65 patients were male (49.6%). The most common reason for requiring HFNC oxygen therapy was pneumonia (n = 75, 57.3%). A complex chronic condition was present in 112 (85.5%) patients. Therapy success was achieved in 116 patients (88.5%). The reason for requiring treatment and the patients' complex chronic condition did not affect the success of the therapy (p = 0.294 and 0.091, respectively). In the first 24 hours of treatment, a significant improvement in pulse rate, respiratory rate, pH, and lactate level were observed in successful HFNC oxygen patients (p < 0.05). In addition, these patients showed a significant improvement in SpO2 and SpO2/FiO2 ratio, and a significant decrease in FiO2 and flow rate (p < 0.05). HFNC oxygen success rate was 95.6% in patients with SpO2/FiO2 ≥ 150 at the 24th hour; it was 58.0% in those with SpO2/FiO2 < 150 (p < 0.001). Caution should be exercised in terms of HFNC oxygen failure in patients with no significant improvement in vital signs and with SpO2/FiO2 < 150 during treatment.
Interleukin-17 in Liver Disease Pathogenesis
Authors: Li Na , Yamamoto Gen , Fuji Hiroaki , Kisseleva Tatiana
Published: June 2021

Interleukin 17A (IL-17A)-producing T helper 17 (Th17) cells were identified as a subset of T helper cells that play a critical role in host defense against bacterial and fungal pathogens. Th17 cells differentiate from Th0 naïve T-cells in response to transforming growth factor β1 (TGF-β1) and IL-6, the cytokines which also drive development of liver fibrosis, require activation of transcription factor retinoic acid receptor-related orphan nuclear receptor gamma t (RORγt). IL-17A signals through the ubiquitously expressed receptor IL-17RA. Expression of IL-17RA is upregulated in patients with hepatitis B virus/hepatitis C virus (HBV/HCV) infections, nonalcoholic steatohepatitis (NASH), alcohol-associated liver disease (AALD), hepatocellular carcinoma (HCC), and experimental models of chronic toxic liver injury. The role of IL-17 signaling in the pathogenesis of NASH- and AALD-induced metabolic liver injury and HCC will be the focus of this review. The role of IL-17A–IL-17RA axis in mediation of the cross-talk between metabolically injured hepatic macrophages, hepatocytes, and fibrogenic myofibroblasts will be discussed.
A Narrative Review of the Risk Factors for Cancer and the Preventive Opportunities: Current Status, Future Perspectives, and Implications for India
Authors: Ramani Vinod K. , Ganesha D. V. , Naik Radheshyam
Published: June 2021

Introduction Clinical cancer can arise from heterogenous pathways through various genetic mutations. Although we cannot predict the timeline by which an individual will develop cancer, certain risk assessment tools can be used among high-risk groups for focusing the preventive activities. As primary level of cancer prevention, healthy lifestyle approach is being promoted. The etiological factors for lung cancer include by-products of industrialization and air pollution. We need to factor the increase in household air pollution as well.

Methods “PubMed” database and Google search engines were used for searching the relevant articles. Search terms with Boolean operators used include “Cancer prevention,” “Missed opportunities in cancer causation,” and “incidence of risk factors.” This review includes 20 studies and other relevant literature that address the opportunities for cancer prevention.

Body The narrative describes the association between many of the risk factors and development of cancer. This includes tobacco, alcohol, infections, air pollution, physical inactivity, diet, obesity, screening and preventive strategies, chemoprevention, biomarkers of carcinogenesis, and factors that prolong the diagnosis of cancer.

Discussion Reports from basic science research provide evidence on the potential of biologically active food components and pharmacological agents for mitigating the risk of cancer and its progression. However, some reports from observational studies and randomized trials have been inconsistent. We need to recognize the impact of sociodemographic factors such as age, sex, ethnicity, culture, and comorbid illness on preventive interventions. Spiral computed tomographic scan is a robust tool for early detection of lung cancer.

Conclusion Infectious etiology for specific cancers provides opportunities for prevention and treatment. The complex interplay between man and microbial flora needs to be dissected, for understanding the pathogenesis of relevant malignancies. For reducing the morbidity of cancer, we need to focus on prevention as a priority strategy and intervene early during the carcinogenic process.
Ultrafast strong-field dissociation of vinyl bromide: An attosecond transient absorption spectroscopy and non-adiabatic molecular dynamics study
Authors: Rott Florian , Reduzzi Maurizio , Schnappinger Thomas , Kobayashi Yuki , Chang Kristina F. , Timmers Henry , Neumark Daniel M. , Vivie-Riedle Regina de , Leone Stephen R.
Published: June 2021

Attosecond extreme ultraviolet (XUV) and soft x-ray sources provide powerful new tools for studying ultrafast molecular dynamics with atomic, state, and charge specificity. In this report, we employ attosecond transient absorption spectroscopy (ATAS) to follow strong-field-initiated dynamics in vinyl bromide. Probing the Br M edge allows one to assess the competing processes in neutral and ionized molecular species. Using ab initio non-adiabatic molecular dynamics, we simulate the neutral and cationic dynamics resulting from the interaction of the molecule with the strong field. Based on the dynamics results, the corresponding time-dependent XUV transient absorption spectra are calculated by applying high-level multi-reference methods. The state-resolved analysis obtained through the simulated dynamics and related spectral contributions enables a detailed and quantitative comparison with the experimental data. The main outcome of the interaction with the strong field is unambiguously the population of the first three cationic states, D1, D2, and D3. The first two show exclusively vibrational dynamics while the D3 state is characterized by an ultrafast dissociation of the molecule via C–Br bond rupture within 100 fs in 50% of the analyzed trajectories. The combination of the three simulated ionic transient absorption spectra is in excellent agreement with the experimental results. This work establishes ATAS in combination with high-level multi-reference simulations as a spectroscopic technique capable of resolving coupled non-adiabatic electronic-nuclear dynamics in photoexcited molecules with sub-femtosecond resolution.
Structural designs, principles, and applications of thin-walled membrane and plate-type acoustic/elastic metamaterials
Authors: Ma Fuyin , Wang Chang , Liu Chongrui , Wu Jiu Hui
Published: June 2021

Many advanced physical properties can be realized by using well-designed acoustic metamaterial (AM) structures, which have significant application value in engineering. In particular, thin-walled membrane, plate, and shell-type structures with deep subwavelength thicknesses that can meet light weight requirements have attracted the attention of many researchers and engineers from various specialized fields. This Tutorial systematically introduced the structural design methods, acoustic/elastic wave attenuation and regulation principles, and engineering applications of thin-walled AMs for low-frequency sound insulation, sound absorption, and vibration reduction. In particular, the design methods and sound insulation/absorption properties of thin-walled AMs for realizing narrow-band and broadband sound attenuation were explored. Furthermore, the local resonance bandgap characteristics, quantitative extraction method for the bending wave bandgap, vibration suppression properties, and the design method for local resonance vibration dampers for elastic wave regulation by thin-walled elastic metamaterials were summarized successively. Moreover, other thin-walled AM applications, such as the wavefront steering performance of thin-walled acoustic/elastic metasurfaces, and the active thin-walled AMs, were introduced as well.
Directed percolation and numerical stability of simulations of digital memcomputing machines
Authors: Zhang Yuan-Hang , Di Ventra Massimiliano
Published: June 2021

Digital memcomputing machines (DMMs) are a novel, non-Turing class of machines designed to solve combinatorial optimization problems. They can be physically realized with continuous-time, non-quantum dynamical systems with memory (time non-locality), whose ordinary differential equations (ODEs) can be numerically integrated on modern computers. Solutions of many hard problems have been reported by numerically integrating the ODEs of DMMs, showing substantial advantages over state-of-the-art solvers. To investigate the reasons behind the robustness and effectiveness of this method, we employ three explicit integration schemes (forward Euler, trapezoid, and Runge–Kutta fourth order) with a constant time step to solve 3-SAT instances with planted solutions. We show that (i) even if most of the trajectories in the phase space are destroyed by numerical noise, the solution can still be achieved; (ii) the forward Euler method, although having the largest numerical error, solves the instances in the least amount of function evaluations; and (iii) when increasing the integration time step, the system undergoes a “solvable–unsolvable transition” at a critical threshold, which needs to decay at most as a power law with the problem size, to control the numerical errors. To explain these results, we model the dynamical behavior of DMMs as directed percolation of the state trajectory in the phase space in the presence of noise. This viewpoint clarifies the reasons behind their numerical robustness and provides an analytical understanding of the solvable–unsolvable transition. These results land further support to the usefulness of DMMs in the solution of hard combinatorial optimization problems.
Pure modulation and accurate measurement of optical beam’s tilt and displacement
Authors: Sun Hengxin , Li Zhi , Guo Hui , Liu Kui , Gao Jiangrui
Published: June 2021

We developed a tilt modulation technique of a laser beam with a wedged crystal. Combined with a phase-compensating crystal, a pure tilt modulation with a wide bandwidth (actually determined by the bandwidth of electro-optic crystals) is realized. By Fourier transformation with a lens, the tilt signal is transformed into displacement. With homodyne detection using a local oscillator of the first-order Hermite–Gauss mode (HG10) and a 4F phase-monitoring system, we measure the displacement and tilt of a laser probe beam. This technique can be used in metrology, such as Newtonian gravitational constant determination and gravitational wave detection, or the calibration of a spatial sensor, such as tilt/displacement sensors.
Optical access to folded transverse acoustic phonon doublet in 6H-SiC
Authors: Shalygin V. A. , Adamov R. B. , Vinnichenko M. Ya. , Moldavskaya M. D. , Firsov D. A.
Published: June 2021

We report on the study of far-infrared transmission in silicon carbide of 6H polytype in the region of IR active folded transverse acoustic (FTA) phonon doublet. Joint analysis of the transmittance spectra obtained at low and high resolutions is performed to determine spectral dependences of the refractive index and absorption coefficient. A dual Lorentz oscillator model is used to simulate the FTA phonon contributions to the dielectric function. The oscillator strengths and phonon lifetimes for both the components of the FTA phonon doublet in 6H-SiC are determined. At temperature decrease from 300 to 5 K, the FTA phonon lifetimes increase more than six times, while the oscillator strengths remain the same.
Crystallization of charged gold particles mediated by nonadsorbing like-charged polyelectrolyte
Authors: Ioka Miyu , Toyotama Akiko , Yamaguchi Megumi , Nozawa Jun , Uda Satoshi , Okuzono Tohru , Yoshimura Masamichi , Yamanaka Junpei
Published: June 2021

We report that the aqueous dispersions of negatively charged submicron-sized colloidal Au particles formed non-close-packed colloidal crystals by the addition of a like-charged linear polyelectrolyte, sodium polyacrylate (NaPAA). Au particles often form irregular aggregates in dispersions because of a strong van der Waals force acting between them. To prevent aggregation, we introduced negative electric charges on particle surfaces. By the addition of NaPAA, colloidal crystals were formed on the bottom of a sample cell because of the supply of Au particles by sedimentation and 2D diffusion even under very dilute conditions. Interparticle potential calculations demonstrated that the addition of NaPAA caused depletion attraction between the particles as well as a significant reduction in the interparticle repulsion because of the electrostatic screening effect. However, the electrostatic repulsion was strong enough to prevent the direct contact of particles in the excluded region between Au particles. Large-area crystals could be obtained by tilting the sample cell. By drying the sample, the Au particles came into contact and the non-space-filling crystals changed into closest packed crystals. These closest packed crystals exhibited a significant enhancement of Raman scattering intensity because of high hot-spot density.
Interfacial engineering for the enhancement of interfacial thermal conductance in GaN/AlN heterostructure
Authors: Wang Quanjie , Wang Xujun , Liu Xiangjun , Zhang Jie
Published: June 2021

Effective heat dissipation is the bottleneck problem for the development and commercialization of GaN-based high-power electronic and photonic devices. To address this challenge and explore the underlying mechanism of phonon transportation across the GaN/AlN heterointerface, in this work, we formed three types of GaN/AlN heterostructures with distinctively different interfacial morphologies by annealing recrystallization approach. It is found that the interfacial thermal conductance (ITC) of GaN/AlN heterostructures can be remarkably improved by tailoring the interfacial crystal structure and phase morphology. Besides the commonly amorphous phase and ideal ordered wurtzite phase, we further found that AlN may present an additional stable rock salt phase at the interfacial region, and its significant effect on interfacial thermal transport has been observed. Using molecular dynamics simulation, we systematically investigated the effects of different GaN/AlN heterojunctions on the ITCs. Our results suggest that heat dissipation at the GaN/AlN interface is dominated by phonons scattered diffusely by the amorphous region at interfaces and the ITC can be significantly enhanced by recrystallizing the amorphous AlN to rock salt one. Furthermore, through phonon vibrational spectrum, we revealed that phonon modes dominate the energy transport across the interfaces of wurtzite AlN/GaN, amorphous AlN/GaN, and rock salt AlN/GaN are significantly different. Finally, we found the ITC increased with the temperature due to the enhanced inelastic phonon scattering and the presence of additional excited phonon modes at higher temperatures. The findings elucidated here provide a clearer insight into the effect of interfacial microstructures on the interfacial thermal resistance of GaN–substrate interface, which also provide a viable heat management strategy for the high-power GaN-based devices.
Network-Based Design of Near-Infrared Lamb-Dip Experiments and the Determination of Pure Rotational Energies of H218O at kHz Accuracy
Authors: Diouf Meissa L. , Tóbiás Roland , Simkó Irén , Cozijn Frank M. J. , Salumbides Edcel J. , Ubachs Wim , Császár Attila G.
Published: June 2021

Taking advantage of the extreme absolute accuracy, sensitivity, and resolution of noise-immune-cavity-enhanced optical-heterodyne-molecular spectroscopy (NICE-OHMS), a variant of frequency-comb-assisted Lamb-dip saturation-spectroscopy techniques, the rotational quantum-level structure of both nuclear-spin isomers of H218O is established with an average accuracy of 2.5 kHz. Altogether, 195 carefully selected rovibrational transitions are probed. The ultrahigh sensitivity of NICE-OHMS permits the observation of lines with room-temperature absorption intensities as low as 10−27 cm molecule−1, while the superb resolution enables the detection of a doublet with a separation of only 286(17) kHz. While the NICE-OHMS experiments are performed in the near-infrared window of 7000–7350 cm−1, the lines observed allow the determination of all the pure rotational energies of H218O corresponding to J values up to 8, where J is the total rotational quantum number. Both network and quantum theory have been employed to facilitate the measurement campaign and the full exploitation of the lines resolved. For example, to minimize the experimental effort, the transitions targeted for observation were selected via the spectroscopic-network-assisted precision spectroscopy (SNAPS) scheme built upon the extended Ritz principle, the theory of spectroscopic networks, and an underlying dataset of quantum chemical origin. To ensure the overall connection of the ultraprecise rovibrational lines for both nuclear-spin isomers of H218O, the NICE-OHMS transitions are augmented with six accurate microwave lines taken from the literature. To produce absolute ortho-H218O energies, the lowest ortho energy is determined to be 23.754 904 61(19) cm−1. A reference, benchmark-quality line list of 1546 transitions, deduced from the ultrahigh-accuracy energy values determined in this study, provides calibration standards for future high-resolution spectroscopic experiments between 0–1250 and 5900–8380 cm−1.
Unraveling current-induced dissociation mechanisms in single-molecule junctions
Authors: Ke Yaling , Erpenbeck André , Peskin Uri , Thoss Michael
Published: June 2021

Understanding current-induced bond rupture in single-molecule junctions is both of fundamental interest and a prerequisite for the design of molecular junctions, which are stable at higher-bias voltages. In this work, we use a fully quantum mechanical method based on the hierarchical quantum master equation approach to analyze the dissociation mechanisms in molecular junctions. Considering a wide range of transport regimes, from off-resonant to resonant, non-adiabatic to adiabatic transport, and weak to strong vibronic coupling, our systematic study identifies three dissociation mechanisms. In the weak and intermediate vibronic coupling regime, the dominant dissociation mechanism is stepwise vibrational ladder climbing. For strong vibronic coupling, dissociation is induced via multi-quantum vibrational excitations triggered either by a single electronic transition at high bias voltages or by multiple electronic transitions at low biases. Furthermore, the influence of vibrational relaxation on the dissociation dynamics is analyzed and strategies for improving the stability of molecular junctions are discussed.
Generation-recombination and 1/f noise in carbon nanotube networks
Authors: Rehman A. , Krajewska A. , Stonio B. , Pavlov K. , Cywinski G. , Lioubtchenko D. , Knap W. , Rumyantsev S. , Smulko J. M.
Published: June 2021

The low-frequency noise is of special interest for carbon nanotubes devices, which are building blocks for a variety of sensors, including radio frequency and terahertz detectors. We studied noise in as-fabricated and aged carbon nanotube networks (CNNs) field-effect transistors. Contrary to the majority of previous publications, as-fabricated devices demonstrated the superposition of generation-recombination (GR) and 1/f noise spectra at a low-frequency range. Although all the devices revealed identical current–voltage characteristics, GR noise was different for different transistors. This effect is explained by the different properties and concentrations of trap levels responsible for the noise. Unexpectedly, exposure of these devices to the atmosphere reduced both the resistance and GR noise due to nanotube's p-doping by adsorbed water molecules from the ambient atmosphere. The presence of the generation recombination noise and its dependences on the environment provides the basis for selective gas sensing based on the noise measurements. Our study reveals the noise properties of CNNs that need to be considered when developing carbon nanotubes-based selective gas sensors.
Transition pathway of hydrogen bond switching in supercooled water analyzed by the Markov state model
Authors: Kikutsuji Takuma , Kim Kang , Matubayasi Nobuyuki
Published: June 2021

In this work, we examine hydrogen-bond (H-bond) switching by employing the Markov State Model (MSM). During the H-bond switching, a water hydrogen initially H-bonded with water oxygen becomes H-bonded to a different water oxygen. MSM analysis was applied to trajectories generated from molecular dynamics simulations of the TIP4P/2005 model from a room-temperature state to a supercooled state. We defined four basis states to characterize the configuration between two water molecules: H-bonded (“H”), unbound (“U”), weakly H-bonded (“w”), and alternative H-bonded (“a”) states. A 16 × 16 MSM matrix was constructed, describing the transition probability between states composed of three water molecules. The mean first-passage time of the H-bond switching was estimated by calculating the total flux from the HU to UH states. It is demonstrated that the temperature dependence of the mean first-passage time is in accordance with that of the H-bond lifetime determined from the H-bond correlation function. Furthermore, the flux for the H-bond switching is decomposed into individual pathways that are characterized by different forms of H-bond configurations of trimers. The dominant pathway of the H-bond switching is found to be a direct one without passing through such intermediate states as “w” and “a,” the existence of which becomes evident in supercooled water. The pathway through “w” indicates a large reorientation of the donor molecule. In contrast, the pathway through “a” utilizes the tetrahedral H-bond network, which is revealed by the further decomposition based on the H-bond number of the acceptor molecule.
Evolution of bacterial steroid biosynthesis and its impact on eukaryogenesis
Authors: Hoshino Yosuke , Gaucher Eric A.
Published: June 2021

Significance

Steroids are one of three major lipid components of the eukaryotic cellular membrane, along with glycerophospolipids and sphingolipids. Steroids have critical roles in eukaryotic endocytosis and thus may have been structural prerequisites for the endocytic acquisition of mitochondria during eukaryogenesis. The evolutionary history of the eukaryotic cellular membrane is poorly understood and, as such, has limited our understanding of eukaryogenesis. We address the evolution of steroid biosynthesis by combining ancestral sequence reconstruction and phylogenetic analyses of steroid biosynthesis genes. Our results indicate that steroid biosynthesis evolved within bacteria in response to the rise of oxygen and was later horizontally transferred to eukaryotes. Membrane properties of early eukaryotes are inferred to have been different than that of modern eukaryotes.
An RNA-centric global view of
Clostridioides difficile
reveals broad activity of Hfq in a clinically important gram-positive bacterium
Authors: Fuchs Manuela , Lamm-Schmidt Vanessa , Sulzer Johannes , Ponath Falk , Jenniches Laura , Kirk Joseph A. , Fagan Robert P. , Barquist Lars , Vogel Jörg , Faber Franziska
Published: June 2021

Significance

Clostridioides difficile
is the leading cause of healthcare-associated diarrhea worldwide following antibiotic treatment. Consequently, there is medical need for novel antibacterial agents acting against
C. difficile
that leave the resident microbiota unharmed. The development of such narrow-spectrum antibiotics requires precise knowledge of the mechanisms that fine-tune gene expression to orchestrate the genomic output at each locus in the genome. We address this issue by defining the global transcriptome architecture of
C. difficile
including noncoding regulatory elements, many of which are expressed during gut colonization. Our analysis of these regulators provides evidence for the global function of Hfq in sRNA binding and stabilization in a gram-positive bacterium.
Tankyrase regulates epithelial lumen formation via suppression of Rab11 GEFs
Authors: Chandrakumar Arun A. , Coyaud Étienne , Marshall Christopher B. , Ikura Mitsuhiko , Raught Brian , Rottapel Robert
Published: June 2021

Rab11 GTPase proteins are required for cytokinesis, ciliogenesis, and lumenogenesis. Rab11a is critical for apical delivery of podocalyxin (PODXL) during lumen formation in epithelial cells. SH3BP5 and SH3BP5L are guanine nucleotide exchange factors (GEFs) for Rab11. We show that SH3BP5 and SH3BP5L are required for activation of Rab11a and cyst lumen formation. Using proximity-dependent biotin identification (BioID) interaction proteomics, we have identified SH3BP5 and its paralogue SH3BP5L as new substrates of the poly-ADP-ribose polymerase Tankyrase and the E3 ligase RNF146. We provide data demonstrating that epithelial polarity via cyst lumen formation is governed by Tankyrase, which inhibits Rab11a activation through the suppression of SH3BP5 and SH3BP5L. RNF146 reduces Tankyrase protein abundance and restores Rab11a activation and lumen formation. Thus, Rab11a activation is controlled by a signaling pathway composed of the sequential inhibition of SH3BP5 paralogues by Tankyrase, which is itself suppressed by RNF146.
Research and analysis of resonant and stiffness of cylindrical dielectric elastomer actuator
Authors: Li Jin , Sun Lijie , Nguyen Tuan Dung , Zhong Tianyi , Liao Xingyu
Published: June 2021

Dielectric elastomer actuators draw great interest in the emerging technology of soft actuations. The drifting of resonance frequency and variable stiffness are commonly existed in soft actuations. This work studied the dynamic performances of a cylindrical dielectric elastomer actuator with coupled loads of tensile forces and variable voltages. The equation of motion for the axial are derived from Euler–Lagrange equation and are reduced into linear ordinary differential equations by the weighted average equivalent linearization method. It is found that the resonant frequency as well as the dynamic behavior can be tuned by variable electrical stimulus on the actuator. An analytical solution of the resonant frequency and equivalent stiffness have been derived in this paper, and have been verified by numerical simulations and experimental measurements. By changing the excitation voltages, the stiffness can be tuned as variable and controllable, which paves the way for future applications of the DE actuators with better performances and resilience.
487 NOTTINGHAM (N-ICE) CREAM-A MORE NUTRITIOUS, PALATABLE AND PREFERRED HIGH PROTEIN, VITAMIN D FORTIFIED VANILLA ICE CREAM-A STEP TOO FAR?
Authors: Sahota A , Wallman J , Worrall R , Sahota O
Published: June 2021

Introduction

Oral Nutritional Supplement (ONS) drinks are commonly used to support nutritional intake in older people, however these are poorly consumed and frequently wasted. Fortified ice-cream offers a more acceptable ONS.

Methods

In collaboration with the University of Nottingham, Department of Food Sciences, we developed a high protein, vanilla ice cream (20 g/120 mL serving), fortified with vitamin D (400 IU)-Nottingham Ice (N-ICE) Cream. An anonymised Google consumer survey was untaken amongst older patients from the Nottingham Osteoporosis Patient Support group. We evaluated (on a rating scale of 1–10): Taste (1 unpleasant to 10 tasty), Mouthfeel (1 grainy to 10 smooth), Smell (1 unpleasant to 10 enticing), Appearance (1 off-putting to 10 inviting) and Colour (1 dull to 10 appealing) of the N-ICE Cream. Further comparison was made with an over-the-counter ONS drink Amyes Complete™ (similar in energy and protein content to N-ICE Cream).

Results

32 participants completed the consumer survey. The mean (SD) age of the patients was 79.1 (4.5) yrs. The mean (SD) score out of 10 for Taste was 8.95 (1.02), Mouthfeel 9.14 (0.98), Smell 8.86 (1.06), Appearance 8.95 (1.12) and Colour 9.10 (1.14). Overall acceptability was 8.92 (1.18). 64% of the participants were able to consume all of the 120 mL tub, 22% ¾, 10% ½ and the remaining only ¼ (4%). 30/32 participants preferred the Taste, 29/32 Mouthfeel and 28/32 the Smell of N-ICE Cream, when compared to the ONS drink, and overall if given a choice, 30/32 (94%) of the participants preferred N-ICE Cream over the Amyes Complete™ ONS drink. The retail cost of Amyes Complete was £2.50 and 28/32 of the participants said they would be willing to pay the same amount for N-ICE Cream.

Conclusion

N-ICE Cream is highly acceptable, nutritious and preferred by the consumer group evaluated when compared to an ONS Amyes Complete™ drink.
508 IMPROVING PATIENT SAFETY BY REDUCING THE INCIDENCE OF MISSED MEDICATIONS IN ELECTIVE SURGICAL PATIENTS
Authors: Halstead A , Williams G
Published: June 2021

Introduction

Following a number of patient safety incidents within elective surgical admissions we sought to improve prescribing practices in elective admissions and take steps to improve similar errors recurring in the future. We found these errors particularly affected frail patients with multiple medications and patients with Parkinson’s disease.

Method

We formed a team of interested junior doctors. By looking at patient pathways we targeted specific areas vulnerable to error. Patients and their drug histories are scrutinised by nurses, doctors and theatre staff during their admission. We highlighted areas where small but important changes could be made. Changes were then made using iterative PDSA cycles. Firstly, the admission proforma had no column for dose or frequency in the drug history, so this was added. Secondly, we instructed the admitting team to prescribe all required medications at the patients’ pre-operative assessment. Thirdly, various prompts were provided to the on-call junior surgical team to provide assurance that all medications for elective patients had been prescribed. A two week time period was chosen to calculate the number of patients who had missed a dose of medication due to lack of prescribing. Effect, ease and sustainability in real world practice were carefully tested by individual teams.

Results

We found that missed doses could be reduced significantly from a 9% error rate to <1%. The most effective intervention resulted from changes to the proforma. Though all interventions were deemed to be effective, only two were considered maintainable in real world practice. These changes have been implemented.

Conclusions

Several processes in the healthcare system are set in stone, as they have been used for years, if not decades. However, we proved that simple changes in operating procedures can make a huge difference to patient safety, health and outcome.