bluuebunny/crossref_metadata_2025_split huggingface dataset:
An analytical gm/ID‐based harmonic distortion prediction method for multistage operational amplifiers
Authors: Xie Qixu , Shi Guoyong 
Published: April 2021

SummaryAn analytical stage‐based harmonic distortion (HD) analysis method for multistage operational amplifiers (Op Amps) is developed in this work. This work contributes two fundamental methods that make the analytical HD prediction possible at the circuit level. Firstly, we propose that the traditionally used first order small‐signal transistor quantities gm (transconductance) and go (output conductance) in the gm/ID design methodology for bulk complementary metal‐oxide‐semiconductor (CMOS) technology can be extended to the higher order quantities gm(k) and go(k) (
). With proper normalization, these quantities become neutral to the device dimensions and operation currents, hence can be precharacterized by sweeping simulations and used as lookup tables. Secondly, we further develop analytical nonlinearity expressions for a set of commonly used amplifier stages, represented as the functions of the nonlinearity parameters gm(k) and go(k) of the transistors that form a stage circuit. A combination of these two fundamental methods on hierarchical nonlinearity modeling enables us to apply the existing analytical HD estimation methods for the stage‐form macromodels to predict the circuit‐level HD behavior, overcoming the need of running repeated simulations under device resizing and rebiasing. The proposed harmonic distortion analysis method has been validated by application to real multistage amplifiers, achieving HD prediction results in excellent agreement to fully transistor‐level circuit simulation results but with substantial speedup.
Ancestral ecological regime shapes reaction to food limitation in the Least Killifish,Heterandria formosa
Authors: Felmy Anja , Leips Jeff , Travis Joseph 
Published: April 2021

AbstractPopulations with different densities often show genetically based differences in life histories. The divergent life histories could be driven by several agents of selection, one of which is variation in per‐capita food levels. Its relationship with population density is complex, as it depends on overall food availability, individual metabolic demand, and food‐independent factors potentially affecting density, such as predation intensity. Here, we present a case study of two populations of a small live‐bearing freshwater fish, one characterized by high density, low predation risk, low overall food availability, and presumably low per‐capita food levels, and the other by low density, high predation risk, high overall food availability, and presumably high per‐capita food levels. Using a laboratory experiment, we examined whether fish from these populations respond differently to food limitation, and whether size at birth, a key trait with respect to density variation in this species, is associated with any such differential responses. While at the lower food level growth was slower, body size smaller, maturation delayed, and survival reduced in both populations, these fitness costs were smaller in fish from the high‐density population. At low food, only 15% of high‐density fish died, compared to 75% of low‐density fish. This difference was much smaller at high food (0% vs. 15% mortality). The increased survival of high‐density fish may, at least partly, be due to their larger size at birth. Moreover, being larger at birth enabled fish to mature relatively early even at the lower food level. We demonstrate that sensitivities to food limitation differ between study populations, consistent with selection for a greater ability to tolerate low per‐capita food availability in the high‐density population. While we cannot preclude other agents of selection from operating in these populations simultaneously, our results suggest that variation in per‐capita food levels is one of those agents.
Tripartite parasitic and symbiotic interactions as a possible mechanism of horizontal gene transfer
Authors: Zhao Chaoyang , Miao Shaoming , Yin Yanfang , Zhu Yanjuan , Nabity Paul , Bansal Raman , Liu Chenxi 
Published: April 2021

AbstractHerbivory is a highly sophisticated feeding behavior that requires abilities of plant defense suppression, phytochemical detoxification, and plant macromolecule digestion. For plant‐sucking insects, salivary glands (SGs) play important roles in herbivory by secreting and injecting proteins into plant tissues to facilitate feeding. Little is known on how insects evolved secretory SG proteins for such specialized functions. Here, we investigated the composition and evolution of secretory SG proteins in the brown marmorated stink bug (Halyomorpha halys) and identified a group of secretory SG phospholipase C (PLC) genes with highest sequence similarity to the bacterial homologs. Further analyses demonstrated that they were most closely related to PLCs of Xenorhabdus, a genus of Gammaproteobacteria living in symbiosis with insect‐parasitizing nematodes. These suggested that H. halys might acquire these PLCs from Xenorhabdus through the mechanism of horizontal gene transfer (HGT), likely mediated by a nematode during its parasitizing an insect host. We also showed that the original HGT event was followed by gene duplication and expansion, leading to functional diversification of the bacterial‐origin PLC genes in H. halys. Thus, this study suggested that an herbivore might enhance adaptation through gaining genes from an endosymbiont of its parasite in the tripartite parasitic and symbiotic interactions.
Electrochemical Tandem Cyclization of Unsaturated Oximes with Diselenides: A General Approach to Seleno Isoxazolines Derivatives with Quaternary Carbon Center
Authors: Gao Wenchao , Li Beibei , Zong Luyi , Yu Lintao , Li Xuyang , Li Qiyang , Zhang Xu , Zhang Sheng , Xu Kun 
Published: April 2021

AbstractElectrochemical oxidative tandem cyclization of unsaturated oximes with diselenides has been developed to provide a general access to seleno isoxazolines containing a quaternary carbon center (35 examples). This novel protocol features with mild reaction conditions (metal‐ and oxidant‐free), good functional group tolerance and promising scalability. Moreover, plausible reaction pathways have been proposed.
On the design and implementation of efficient antennas for high frequency‐radio frequency identification read/write devices
Authors: Ofosu Addo Ernest , Kommey Benjamin , Selasi Agbemenu Andrew , Kumbong Hermann 
Published: April 2021

AbstractThis article describes an in‐depth methodical approach to the development of efficient high‐frequency (HF) antennas for use in radio frequency identification (RFID) systems operating at 13.56 MHz. It presents brief theory relevant to RFID communication and sets up a framework within which features and requirements of antennas are linked to key design parameters such as antenna form‐factor and size; RF power level, material and communication protocol. Tuning circuits necessary to adjust the resonance and power matching characteristics of antennas for good transponder interrogation and response recovery are discussed. To validate the approaches outlined, a stepwise design and measurement of an HF antenna for an ISO/IEC 15693 compliant read/write device (RWD) is described. Common practical problems that are often encountered in such design processes are also commented on. The prototyped antenna was tuned, connected to the RWD via a 50 coaxial cable and tested.
Markov chain Monte Carlo methods for hierarchical clustering of dynamic causal models
Authors: Yao Yu , Stephan Klaas E. 
Published: April 2021

AbstractIn this article, we address technical difficulties that arise when applying Markov chain Monte Carlo (MCMC) to hierarchical models designed to perform clustering in the space of latent parameters of subject‐wise generative models. Specifically, we focus on the case where the subject‐wise generative model is a dynamic causal model (DCM) for functional magnetic resonance imaging (fMRI) and clusters are defined in terms of effective brain connectivity. While an attractive approach for detecting mechanistically interpretable subgroups in heterogeneous populations, inverting such a hierarchical model represents a particularly challenging case, since DCM is often characterized by high posterior correlations between its parameters. In this context, standard MCMC schemes exhibit poor performance and extremely slow convergence. In this article, we investigate the properties of hierarchical clustering which lead to the observed failure of standard MCMC schemes and propose a solution designed to improve convergence but preserve computational complexity. Specifically, we introduce a class of proposal distributions which aims to capture the interdependencies between the parameters of the clustering and subject‐wise generative models and helps to reduce random walk behaviour of the MCMC scheme. Critically, these proposal distributions only introduce a single hyperparameter that needs to be tuned to achieve good performance. For validation, we apply our proposed solution to synthetic and real‐world datasets and also compare it, in terms of computational complexity and performance, to Hamiltonian Monte Carlo (HMC), a state‐of‐the‐art Monte Carlo technique. Our results indicate that, for the specific application domain considered here, our proposed solution shows good convergence performance and superior runtime compared to HMC.
Transitioning from university to postgraduate medical training: A narrative review of work readiness of medical graduates
Authors: Padley James , Boyd Sarah , Jones Alison , Walters Lucie 
Published: April 2021

AbstractContextWork readiness is often described in terms of the clinical competence medical graduates bring to day 1 of internship. Despite being increasingly viewed as a key graduate outcome, work readiness has remained poorly defined.ObjectiveThis narrative review draws on the international literature to explore how different research methods provide differing insight into what constitutes work readiness of medical graduates. From this, we explored contributory factors and developed a conceptual framework to better understand work readiness.MethodsDatabases were searched using the terms including “ready,” “readiness,” “preparedness,” “medical graduates,” “intern,” and “junior doctor.” Information was summarized using a textual description template that included information on study setting, participants, methodologies, limitations, and key result areas (including measures/themes and study conclusions). Consensus discussions between authors led to the naming and understanding of the key themes.ResultsSeventy studies were included in the review. Study participants included final‐year medical students (n = 20), junior doctors early in internship (n = 24), and junior doctors late in internship or postgraduate year 2 and above (n = 23). Most studies explored work readiness through the retrospective self‐report of the students and/or junior doctor participants. Quantitative research methods elaborated on key skills‐based competencies, whereas qualitative research methods provided insight into key contextual and individual characteristics that contributed to preparedness.ConclusionsDifferent research methods provided insight into competencies, as well as individual and contextual aspects, associated with preparedness for practice. The transition from university to clinical practice is significant and requires personal capability and confidence, as well as a supportive training context. Enabling students to engage authentically in clinical environments enhanced preparedness by promoting understanding of role and responsibility. Individual resilience is important, but contextual factors, including provision of adequate support and feedback, can enhance or subtract from feeling prepared. We propose a novel conceptual framework for better understanding work readiness.
Synthesis of O‐linked Cyclitol Analogues of Gilvocarcin M and Antibacterial Activity
Authors: Sharif Ehesan U. , Shi Pei , O'Doherty George A. 
Published: April 2021

AbstractTwo unnatural regioisomeric glycosylated Gilvocarcin analogues were proposed as model compounds to study the origin behind the biosynthetic development of the Gilvocarcins, a class of bioactive C‐aryl glycoside natural products. More specifically, the origins behind the proposed O‐ to C‐glycoside migration in the evolution of the biosynthesis for these classes of Angucycline antibiotic natural products. For stability reasons a 5a‐carbasugar motif was used to mimic the sugar portion of the molecule and of synthetic ease the proposed abiotic rearrangement move the sugar analogue along with its O‐glycoside linkage. The two proposed regioisomeric analogues were synthesized by a regio‐divergent synthetic pathway and featured a Mitsunobu‐like invertive cyclictolization reaction to install the carbasugar motif. The two regioisomeric Gilvocarcin analogues were evaluated as antibiotic with Gilvocarcin M as a control. Only one of the two isomers showing weak antibiotic activity as compared to Gilvocarcin M.
Strategic targeting of non‐small‐cell lung cancer utilizing genetic material‐based delivery platforms of nanotechnology
Authors: Chaudhary Swati , Singh Amit , Kumar Pankaj , Kaushik Mahima 
Published: April 2021

AbstractSeveral limitations of conventional cancer treatment such as non‐specific targeting, solubility problems, and ineffective entry of chemotherapeutics into cancer cells can be overcome by using nanotechnology targeted drug delivery systems. Some combinations of biomolecules and nanoparticles have proven to be excellent therapeutics for Non‐small cell lung cancer (NSCLC) in the last decades. Targeted gene delivery has shown in vivo as well as in vitro promising results with therapeutic efficacy. Gene therapy has shown enhanced transfection efficiency and better targeting potential on several NSCLC cell lines. Still, there are several challenges in nanoparticle‐mediated gene therapy, which include stability of biomolecules and nanoparticles during delivery, managing their biodistribution, and reducing the possible cytotoxic effects of the nanoparticles, which need to be solved before clinical trials. Evaluation of therapeutic efficacy of biomolecules and nanoparticle combination in gene therapy must be established to expand the application of nano‐gene therapy in cancer treatment.
Association of an insertion mutation in PRRT2 with hereditary spastic paraplegia accompanied by polyneuropathy
Authors: Wang Zhaoyu , Dong Huijie , Ji Xiaofei , Luan Siyu , Cao Hua 
Published: April 2021

AbstractBackgroundHereditary spastic paraplegia is a rare familial hereditary neurodegenerative disease caused by multiple autosomal dominant mutations. More than 50 mutant genes have been reported to be associated with this disease.MethodsIn this study, we have reported a rare insertion mutation site in PRRT2 that caused a familial disorder of hereditary spastic paraplegia accompanied by polyneuropathy.ResultsWe used second‐generation sequencing of samples of the proband's familial genome and found an insertion mutation of C/CC in NM_001256443:c.641dupC that was localized to the second exon of PRRT2. This functional mutation can cause an amino acid sequence change (arginine >proline) and dysfunctional neuronal transmembrane proteins, which might have been related to the onset of hereditary spastic paraplegia accompanied by polyneuropathy in the family reported in this study.ConclusionThe discovery of this mutation site provides an important theoretical basis for specific gene‐based diagnosis and treatment of hereditary spastic paraplegia.
Opportunities to improve nitrogen use efficiency in an intensive vegetable system without compromising yield
Authors: Suter Helen , Pandey Arjun , Lam Shu Kee , Davies Rohan , Hassan Rifaath , Riches David , Chen Deli 
Published: April 2021

AbstractIntensive vegetable cropping systems rely heavily on nitrogen (N) inputs from multiple synthetic and organic fertilizer applications. The majority of applied N is lost to the environment through numerous pathways, including as nitrous oxide (N2O). A field trial was conducted to examine the opportunities to reduce N input in an intensive vegetable system without compromising yield. Treatments applied were control (no N), manure (M, 408 kg N ha–1 from chicken manure), grower practice (GP, 408 kg N ha–1 from chicken manure + 195 kg N ha–1 from fertilizer), and 2/3 GP (two‐thirds of the total N input in GP), all with and without 3,4‐dimethylpyrazole phosphate (DMPP). Nitrogen recovery in the GP treatment was determined using 15N‐labeled fertilizer. Using only manure significantly lowered celery (Apium graveolens L.) yield and apparent N use efficiency (ANUE) compared with GP. Reducing N input by one‐third did not affect yield or ANUE. Use of DMPP increased ANUE despite no yield improvement. More than 50% of the applied N in the GP treatment was lost to the environment, with almost 10 kg N ha–1 emitted as N2O over the season, which was 67 times more than from the control. Reducing the N input by one‐third or using manure only reduced N2O emissions by more than 70% relative to GP. This study shows that there is a clear opportunity to reduce N input and N2O emissions in high‐fertilizer‐input vegetable systems without compromising vegetable yield.
The structure of graphs with no W4 immersion
Authors: DeVos Matt , Malekian Mahdieh 
Published: April 2021

AbstractThis paper gives a precise structure theorem for the class of graphs which do not contain as an immersion. This strengthens a previous result of Belmonte et al. that gives a rough description of this class. In fact, we prove a stronger theorem concerning rooted immersions of where one terminal is specified in advance. This stronger result is key in a forthcoming structure theorem for graphs with no immersion.
Diagnostic Performance of a Lower‐dose Contrast‐Enhanced 4D Dynamic MR Angiography of the Lower Extremities at 3 T Using Multisegmental Time‐Resolved Maximum Intensity Projections
Authors: Raczeck Paul , Fries Peter , Massmann Alexander , Minko Peter , Frenzel Felix , Woerner Tobias , Buecker Arno , Schneider Guenther K. 
Published: April 2021

BackgroundFor peripheral artery disease (PAD), MR angiography (MRA) is a well‐established diagnostic modality providing morphologic and dynamic information comparable to digital subtraction angiography (DSA). However, relatively large amounts of contrast agents are necessary to achieve this.PurposeTo evaluate the diagnostic accuracy of time‐resolved 4D MR‐angiography with interleaved stochastic trajectories (TWIST‐MRA) by using maximum intensity projections (MIPs) of dynamic images acquired with reduced doses of contrast agent.Study TypeRetrospective.PopulationForty adult PAD patients yielding 1088 artery segments.Field Strength/SequenceA 3.0 T, time‐resolved 4D MR‐angiography with TWIST‐MRA and MIP of dynamic images.AssessmentDSA was available in 14 patients (256 artery segments) and used as reference standard. Three‐segmental MIP reconstructions of TWIST‐images after administration of 3 mL of gadolinium‐based contrast agent (Gadoteridol/Prohance®, 0.5 M) per anatomical level (pelvis, thighs, and lower legs) yielded 256 artery segments for correlation between MRA and DSA. Three independent observers rated image quality (scale: 1 [nondiagnostic] to 4 [excellent]) and the degree of venous overlay (scale: 0 [none] to 2 [significant]) for all segments. Diagnostic accuracy for the detection of >50% stenosis and artery occlusion was calculated for all observers.Statistical TestsBinary classification test (sensitivity, specificity, positive/negative predictive values, diagnostic accuracy). Intraclass correlation coefficients (ICCs), logistic regression analysis with comparison of areas under the receiver‐operating‐characteristics (ROC) curves (AUCs) with the DeLong method. Bland–Altman‐comparison.ResultsHigh diagnostic performance was achieved for the detection of >50% stenosis (sensitivity 92.9% [84.3–99.9% (95%‐CI)] and specificity 98.5% [95.7–99.8% (95%‐CI)]) and artery occlusion (sensitivity 93.1% [77.2–99.2% (95%‐CI)] and specificity 99.1% [96.9–99.9% (95%‐CI)]). Inter‐reader agreement was excellent with ICC values ranging from 0.95 to 1.0 for >50% artery stenosis and occlusion. Image quality was good to excellent for both readers (3.41 ± 0.72, 3.33 ± 0.65, and 3.38 ± 0.61 [mean ± SD]) with good correlation between observer ratings (ICC 0.71–0.81). No significant venous overlay was observed (0.06 ± 0.24, 0.23 ± 0.43 and 0.11 ± 0.45 [mean ± SD]).Data ConclusionMIPs of dynamic TWIST‐MRA offer a promising diagnostic alternative necessitating only reduced amounts (50%) of gadolinium‐based contrast agents for the entire runoff vasculature.Evidence Level3Technical EfficacyStage 2
Digital radiography reject analysis of examinations with multiple rejects: an Australian emergency imaging department clinical audit
Authors: Stephenson‐Smith Brittany , Neep Michael J , Rowntree Pamela 
Published: April 2021

AbstractIntroductionThe largest source of manmade ionising radiation exposure to the public stems from diagnostic medical imaging examinations. Reject analysis, a form of quality assurance, was introduced to minimise repeat exposures. The purpose of this study was to analyse projection‐specific reject rates and radiographic examinations with multiple rejects.MethodsA retrospective audit of rejected radiographs was undertaken in a busy Australian metropolitan emergency digital X‐ray room from March to June 2018. The data were collected by reject analysis software embedded within the X‐ray unit. Reject rates, and reasons for rejection for each X‐ray projection were analysed.ResultsData from 11, 596 images showed overall reject rate was 10.3% and the overall multiple reject rate was 1.3%. The projections with both a high number and high percentage of rejects were antero‐posterior (AP) chest (175, 18.1%), AP pelvis (78, 22.5%), horizontal beam hip (61, 33.5%) and horizontal beam knee (116, 30.5%). The projections with both a high frequency and multiple reject rate were horizontal beam knee (32, 8.4%) and horizontal beam hip (17, 9.3%). The top reasons for multiple rejects were positioning (67.1%) and anatomy cut‐off (8.4%).ConclusionsThe findings of this study demonstrated that projection‐specific reject and multiple reject analysis in digital radiography is necessary in identifying areas for quality improvement which will reduce radiation exposure to patients. Projections that were frequently repeated in this study were horizontal beam knee and horizontal beam hip. Future research could involve re‐auditing the department following the implementation of improvement strategies to reduce unnecessary radiation exposure.