bluuebunny/crossref_metadata_2025 huggingface dataset:
Using Delaunay triangulation to sample whole‐specimen color from digital images
Authors: Valvo Jennifer J. , Aponte Jose David , Daniel Mitch J. , Dwinell Kenna , Rodd Helen , Houle David , Hughes Kimberly A.
Published: August 2021

Color variation is one of the most obvious examples of variation in nature, but biologically meaningful quantification and interpretation of variation in color and complex patterns are challenging. Many current methods for assessing variation in color patterns classify color patterns using categorical measures and provide aggregate measures that ignore spatial pattern, or both, losing potentially important aspects of color pattern.

Here, we present Colormesh, a novel method for analyzing complex color patterns that offers unique capabilities. Our approach is based on unsupervised color quantification combined with geometric morphometrics to identify regions of putative spatial homology across samples, from histology sections to whole organisms. Colormesh quantifies color at individual sampling points across the whole sample.

We demonstrate the utility of Colormesh using digital images of Trinidadian guppies (Poecilia reticulata), for which the evolution of color has been frequently studied. Guppies have repeatedly evolved in response to ecological differences between up‐ and downstream locations in Trinidadian rivers, resulting in extensive parallel evolution of many phenotypes. Previous studies have, for example, compared the area and quantity of discrete color (e.g., area of orange, number of black spots) between these up‐ and downstream locations neglecting spatial placement of these areas. Using the Colormesh pipeline, we show that patterns of whole‐animal color variation do not match expectations suggested by previous work.

Colormesh can be deployed to address a much wider range of questions about color pattern variation than previous approaches. Colormesh is thus especially suited for analyses that seek to identify the biologically important aspects of color pattern when there are multiple competing hypotheses or even no a priori hypotheses at all.
Resiliency in the E‐mini futures market
Authors: Fishe Raymond P. H. , Haynes Richard , Onur Esen
Published: August 2021

We study how quickly liquidity is replenished on the order book in E‐mini futures. The results show that participants who use patient methods, such as limit orders, are often fast to place new orders, while those using impatient market orders are slow to re‐enter the market. These delays are a function of state constants, such as firm types, state conditions, such as whether the order is price improving, and time‐varying covariates, such as the volume of trade during the gap. We also find support for the view that certain traders delay providing liquidity during active markets to avoid informed trading.
Strategies for feature extraction from structural brain imaging in lesion‐deficit modelling
Authors: Kasties Vanessa , Karnath Hans‐Otto , Sperber Christoph
Published: August 2021

High‐dimensional modelling of post‐stroke deficits from structural brain imaging is highly relevant to basic cognitive neuroscience and bears the potential to be translationally used to guide individual rehabilitation measures. One strategy to optimise model performance is well‐informed feature selection and representation. However, different feature representation strategies were so far used, and it is not known what strategy is best for modelling purposes. The present study compared the three common main strategies: voxel‐wise representation, lesion‐anatomical componential feature reduction and region‐wise atlas‐based feature representation. We used multivariate, machine‐learning‐based lesion‐deficit models to predict post‐stroke deficits based on structural lesion data. Support vector regression was tuned by nested cross‐validation techniques and tested on held‐out validation data to estimate model performance. While we consistently found the numerically best models for lower‐dimensional, featurised data and almost always for principal components extracted from lesion maps, our results indicate only minor, non‐significant differences between different feature representation styles. Hence, our findings demonstrate the general suitability of all three commonly applied feature representations in lesion‐deficit modelling. Likewise, model performance between qualitatively different popular brain atlases was not significantly different. Our findings also highlight potential minor benefits in individual fine‐tuning of feature representations and the challenge posed by the high, multifaceted complexity of lesion data, where lesion‐anatomical and functional criteria might suggest opposing solutions to feature reduction.
Public trust and the COVID‐19 vaccination campaign: lessons from the Philippines as it emerges from the Dengvaxia controversy
Authors: Mendoza Ronald U. , Dayrit Manuel M. , Alfonso Cenon R. , Ong Madeline Mae A.
Published: August 2021

While the entire world prepares and begins to roll out COVID‐19 vaccines, the Philippines is still reeling from the consequences of the Dengvaxia controversy in 2016. Those highly political events led to the erosion of public trust in leaders and a significant damage to vaccine confidence in the country, now potentially impacting the uptake of COVID‐19 vaccines. We discuss how public trust and confidence can be rehabilitated through accountability, transparency, and proper communication from the most trusted sources of the population. We also highlight key lessons for policymakers and leaders on allowing science to take the front seat, and politics behind, for the safety and well‐being of the people during this public health crisis.
Baicalin regulates mRNA expression of VEGF‐c, Ang‐1/Tie2, TGF‐β and Smad2/3 to inhibit wound healing in streptozotocin‐induced diabetic foot ulcer rats
Authors: Mao Xuefei , Li Zhi , Li Baogang , Wang Haiping
Published: August 2021

Diabetic foot ulcer (DFU) is biggest life threats globally and increases their severity increases health complications for health of patients. The present study was investigated to recover the wound healing activity of baicalin in STZ‐induced DFU rats by evaluating biochemical and molecular markers. The experimental animals induced with diabetes and excision wounds were treated with different doses of baicalin (25, 50, and 100 mg/kg). The serum glucose level, body weight and food intake were measured. In addition, DFU rat groups showed decreased food intake and increased body weight. The tissue was subjected to biochemical evaluation, histopathology, quantitative polymerase chain reaction and Western blot analysis. Histopathology reports revealed that diabetic wound control (DWC) + baicalin (100 mg/kg) treated group showed more than 90% recovery with more epithelization and remarkably improved angiogenesis and infiltration of the inflammatory cells. In this study we also proved that upregulated the p‐ERK, ERK, HSP27, and p‐HSP27 protein expression and mRNA expression of Ang‐1, VEGF‐c, TGF‐β, Tie‐2, and SMAD2/3 implicating the potential antidiabetic and wound healing property of baicalin. Thus, baicalin is a potential therapeutic candidate for a diabetic foot ulcer and chronic wounds treatment.
Hydration of selenolate moiety: Ab initio investigation of properties of O–H⋯Se(–) hydrogen bonds in CH3Se(–)⋯(H2O)n clusters
Authors: Karpov Valerii V. , Puzyk Aleksandra M. , Tolstoy Peter M. , Tupikina Elena Yu.
Published: August 2021

This work is devoted to investigations of the influence of O–H···Se(–) hydrogen bonds on the electronic shells of selenolate R–Se(–) fragment (R═CH3). The geometric, energetic and nuclear magnetic resonance (NMR) spectral parameters for various conformers of CH3Se(–)⋯(H2O)n clusters with n = 0–6 were calculated at CCSD/aug‐cc‐pVDZ level of theory. For selenolate anion CH3Se(–) solvation free energy was calculated, and for water media it is equal to −71.41 kcal/mol. For O–H···Se(–) hydrogen bonds the proportionality coefficients between QTAIM parameters at (3; −1) bond critical point and the strength of an individual hydrogen bond ∆E were proposed. It was shown, that despite a relative weakness of O–H···Se(–) hydrogen bonds, the outer electronic shell of the selenium atom changes significantly upon formation of each hydrogen bond. This, in turn, cause the dramatic change of NMR parameters of selenium nuclei.
Pseudospectral implementations of long‐range corrected density functional theory
Authors: Cao Yixiang , Halls Mathew D. , Vadicherla Tati Reddy , Friesner Richard A.
Published: August 2021

We have implemented pseudospectral density‐functional theory (DFT) with long‐range corrected DFT functionals (PS‐LRC) in quantum mechanics package Jaguar, and applied it in the calculations of geometry optimizations, dimmer interaction energies, polarizabilities and first‐order hyperpolarizabilities, harmonic vibrational frequencies, S1 and T1 excitation energies, singlet‐triplet gaps, charge transfer numbers, oscillator strengths, reaction barrier heights, electron‐transfer couplings, and charge‐transfer excitation energies. From our accuracy benchmark analysis, PS grids, PS dealiasing functions, PS atomic corrections, PS multigrid strategy, PS length scales, and PS cutoff scheme perform well in PS DFT with LRC density functionals with very small and ignorable deviations when compared to the conventional spectral (CS) method. The timing benchmark study of S1 excitation energy calculations of fullerenes (Cn, n up to 540) demonstrates that PS‐LRC achieves 1.4–8.4‐fold speedups in SCF, 22–32‐fold speedups in Tamm‐Dancoff approximation, and 6–15‐fold speedups in total wall clock time with an average error 0.004 eV of excitation energies compared to the CS method.
Involvement of TRPV4 in changes in rapidly inactivating potassium channels in the early stage of pilocarpine‐induced status epilepticus in mice
Authors: Xu Weixing , Wang Yue , Qi Xiuting , Li Kunpeng , Zhou Li , Sha Sha , Wang Xiaoli , Wu Chunfeng , Du Yimei , Chen Lei
Published: August 2021

The rapidly inactivating potassium current (IA) is important in controlling neuronal action potentials. Altered IA function and K+ channel expression have been found in epilepsy, and activation of the transient receptor potential vanilloid 4 (TRPV4) channel is involved in epilepsy pathogenesis. This study examined whether TRPV4 affects Kv4.2 and K+ channel interacting protein (KCHIP) expression and IA changes following pilocarpine‐induced status epilepticus (PISE) in mice. Herein, hippocampal protein levels of Kv4.2 and KCHIP2 increased 3 h–3 d and decreased 7–30 d; that of KCHIP1 increased 3–24 h and decreased 3–30 d post‐PISE. The TRPV4 antagonist HC‐067047 attenuated the increased protein levels of Kv4.2 and KCHIP2 but not that of KCHIP1 post‐PISE. The TRPV4 agonist GSK1016790A increased hippocampal protein levels of Kv4.2 and KCHIP2 but had no effect on KCHIP1 expression. HC‐067047 attenuated the increased IA in hippocampal pyramidal neurons 24 h and 3 d post‐PISE. GSK1016790A increased IA in hippocampal pyramidal neurons, shifting the voltage‐dependent inactivation curve toward depolarization. The GSK1016790A‐induced increase of IA was blocked by protein kinase A and calcium/calmodulin‐dependent kinase II antagonists but was unaffected by protein kinase C antagonists. We conclude that TRPV4 activation may be responsible for the increases of Kv4.2 and KCHIP2 expression in hippocampi and IA in hippocampal pyramidal neurons in PISE mice, which are likely compensatory measures for hyperexcitability at the early stage of epilepsy.
Placental spectrum features between mesenchymal dysplasia and partial hydatidiform mole coexisting with a live fetus
Authors: Marinho Márcia , Nogueira Rosete , Soares Célia , Melo Mónica , Godinho Cristina , Brito Conceição
Published: August 2021

We report a case of a singleton hydrops pregnancy with placental gross and microscopic features between partial hydatidiform mole (PHM) and placental mesenchymal dysplasia (PMD) in a diploid live fetus. Pregnancy was complicated by early onset of growth restriction and pre‐eclampsia. A female newborn was born at 29 weeks with no congenital malformations. Histology of the placenta revealed mixed phenotype of PMD and PHM, and genetic test results were normal.
Depression and suicidal ideation among dental students of Southern Saudi Arabia: A cross sectional study
Authors: Almoammar Salem , Alqarni Kholod Abdurhman , Alnazeh Abdullah A. , Alshahrani Razan Mohamed , Sundram Frederick , Alyami Mohsen , Alyami Hussain
Published: August 2021

Purpose

To assess depression and suicidal ideation among dental students at King Khalid University College of Dentistry, Abha, Saudi Arabia.

Methods

A cross‐sectional questionnaire‐based study was carried out among dental students between January and March 2020. The Arabic version of the Patient Health Questionnaire (PHQ‐9) was used to assess depression, while suicidal ideation was assessed using three questions related to suicidal behaviors drawn from the literature.

Results

A total of 218 participants completed the questionnaires. More than 40% of the participants experienced depression while the prevalence of suicidal ideation was 48.2%; around a third of the sample had suicidal ideation, and half of which made a suicidal attempt in the preceding year (p < 0.05). There was a lack of association between depression severity and suicidal ideation.

Conclusion

A large proportion of dental students experienced depression and suicidal ideation. These findings invite in depth analysis of the causative and contributing factors for such high rates as well as ways for addressing them.
Tenofovir alafenamide for prevention and treatment of hepatitis B virus reactivation and de novo hepatitis
Authors: Inada Kento , Kaneko Shun , Kurosaki Masayuki , Yamashita Koji , Kirino Sakura , Osawa Leona , Hayakawa Yuka , Sekiguchi Shuhei , Higuchi Mayu , Takaura Kenta , Maeyashiki Chiaki , Tamaki Nobuharu , Yasui Yutaka , Itakura Jun , Takahashi Yuka , Tsuchiya Kaoru , Nakanishi Hiroyuki , Okamoto Ryuichi , Izumi Namiki
Published: August 2021

Background and Aim

Administration of tenofovir alafenamide (TAF) as prevention or treatment of hepatitis B virus (HBV) reactivation is not well known. The aim of this study is to reveal the efficacy and safety of TAF against HBV reactivation.

Methods

Entecavir (ETV) and TAF were given to 66 and 11 patients, respectively, as prophylaxis against or treatment of HBV reactivation during chemotherapy or immune suppression therapy from January 2010 to June 2020. The antiviral effects and safety were assessed.

Results

At week 24, the antiviral effects on patients receiving ETV and TAF were similar in terms of reduction of HBV DNA (−2.83 ± 1.45log IU/mL vs −3.05 ± 2.47log IU/mL; P = 0.857) and achieving undetectable levels of HBV DNA (78.8 vs 90.9%; P = 0.681). There was no significant difference in the decrease in the estimated glomerular filtration rate (eGFR) between the two groups (−0.62 ± 11.2 mL/min/1.73 m2 vs −3.67 ± 13.2 mL/min/1.73 m2; P = 0.291).

Conclusion

TAF is safe and effective against HBV reactivation.
Respiratory viruses associated with severe mechanically ventilated pneumonia in children
Authors: El‐Nawawy Ahmed , Antonios Manal AM. , Meheissen Marwa A. , Fahim Marwan M.
Published: August 2021

The burden of pneumonia, especially that caused by respiratory viruses, is markedly high in the pediatric age group. This study aimed to assess viral agents causing severe pneumonia among mechanically ventilated patients. Nonbronchoscopic bronchoalveolar lavage was performed for pediatric patients having severe pneumonia indicated for mechanical ventilation to be tested with a multiplex PCR immediate diagnosis of their etiologic pathogen. Among the 75 patients recruited, viral agents were detected in 73.4% of cases. Rhinovirus and respiratory syncytial virus (RSV) were the most common viruses detected in 32.1% and 29.5%, respectively. The rate of viral infection showed a clear increased incidence in the winter season. The mortality rate among viral‐associated severe pneumonia reached 56.36%. Odds of mortality increased threefolds in presence of comorbid conditions and 10‐folds with congenital heart disease. The study demonstrated the neglected importance of rhinovirus besides RSV in causing severe critical pneumonia in the pediatric age.
The biomechanical disadvantage of dysplastic hips
Authors: Harris Michael D. , Shepherd Molly C. , Song Ke , Gaffney Brecca M. M. , Hillen Travis J. , Harris‐Hayes Marcie , Clohisy John C.
Published: August 2021

Developmental dysplasia of the hip (DDH) is strongly associated with an increased risk for hip osteoarthritis. Skeletal deformities undeniably contribute to detrimental biomechanical loading in dysplastic hips, but cannot explain all types of damage and symptoms that patients with DDH experience. Characterizing the geometry and function of the muscles spanning the hip is a logical next step in our progression of knowledge about DDH pathomechanics. In this study, we compared skeletal geometry, muscle volumes, intramuscular fatty infiltration, moment arms, and isometric strength in patients with DDH (N = 20) to healthy controls (N = 15). Femoral coverage was significantly less in patients (p < 0.001, Cohen's d effect size = 2.2), femoral neck‐shaft angles were larger (p = 0.001, d = 1.3), and hip joint centers (HJCs) were more lateral (p = 0.001, d = 1.3). These skeletal abnormalities were associated with smaller abductor muscle moment arms in patients with DDH (e.g., gluteus medius [GMED]: p = 0.001, d = 1.2). Patients with DDH also had larger GMED volumes (p = 0.02, d = 0.83), but no differences in fatty infiltration, compared to controls. Isometric strength of the hip abductors, extensors, and flexors was lower in patients, but not significantly different from controls. The abnormal skeletal geometry, lateralized HJC, and reduced muscle moment arms represent a chronic biomechanical disadvantage under which patients with DDH operate. This phenomenon causes increased demand on the abductor muscles and results in high medially and superiorly directed joint reaction forces, which can explain reports of superomedial femoral cartilage damage in patients. The abnormal muscle geometry and function, in context with abnormal skeletal structure, are likely strong, but underappreciated, contributors to damaging loads in DDH.
Loss of HER2‐positivity following neoadjuvant targeted therapy for breast cancer is not associated with inferior oncologic outcomes
Authors: Wetzel Catherine L. , Sutton Thomas L. , Gardiner Stuart , Farinola Maryam , Johnson Nathalie , Garreau Jennifer R.
Published: August 2021

Background

Patients with human epidermal growth factor receptor 2 (HER2)‐positive breast cancer are treated with trastuzumab‐based neoadjuvant therapy (NAT); some patients with residual disease post‐NAT show loss of HER2 amplification and has been inconsistently associated with oncologic outcomes.

Methods

We queried our multi‐institutional cancer registry for women with HER2‐positive breast cancer undergoing NAT from 2011 to 2018. Clinicopathologic, treatment‐related, and outcomes data were collected. Kaplan–Meier and Cox proportional hazards analysis were used to evaluate oncologic outcomes.

Results

A total of 348 patients were identified; 166 (48%) had a pathologic complete response. Of the 182 patients with residual disease, 87 (48%) were HER2‐positive, 34 (19%) were HER2‐negative, and 61 (33%) were HER2‐unknown, with a median follow‐up of 44 months. There were no factors associated with HER2 loss apart from age. On Kaplan–Meier analysis, estimated 5‐year recurrence‐free survival (RFS) and overall survival (OS) for patients with HER2‐positive residual disease was 81% and 92%, respectively, and 74% (log rank p = 0.75) and 81% (p = 0.35) in patients with HER2‐negative residual disease.

Conclusion

The loss of HER2‐positivity following NAT is not associated with worse 5‐year RFS or OS. We do not recommend retesting HER2 status following NAT for the purpose of clinical management; these patients should complete targeted adjuvant therapy.
Role of three‐phase solvent system in the counter‐current chromatography
Authors: Jing Jun‐Xian , Pei Dong , Di Duo‐Long , Huang Xin‐Yi
Published: August 2021

In counter‐current chromatography, the separation efficiency greatly depends on the partitioning ability of the separated substance between the stationary phase and the mobile phase. Partitioning ability is mainly represented by the parameter partition coefficient which is one of the important parameters to evaluate the separation effect of counter‐current chromatography. The scope of the partition coefficient value mainly depends on the solvent system. A suitable solvent system election is, therefore, a critical role in the separation of counter‐current chromatography. The existing solvent systems that are widely used are mainly two‐phase solvent systems. It is difficult to decide on an appropriate solvent system for the separation of compounds with a wide polarity range, which promotes the development of the three‐phase solvent system in counter‐current chromatography. This review mainly described the origin, development history of three‐phase solvent system, summarized the volume ratios and volume fractions of the upper, middle, and lower phases of nearly 50 three‐phase solvent systems, their advantages, and disadvantages in counter‐current chromatography. In addition, the challenges and future perspectives on three‐phase solvent systems in counter‐current chromatography also are discussed in this review.
Hearing Aid Use in Children With Unilateral Hearing Loss: A Randomized Crossover Clinical Trial
Authors: Benchetrit Liliya , Stenerson Matthew , Ronner Evette A. , Leonard Heidi J. , Aungst Holle , Stiles Derek J. , Levesque Patricia A. , Kenna Margaret A. , Anne Samantha , Cohen Michael S.
Published: August 2021

Objectives/Hypothesis

In children with mild to moderately severe unilateral hearing loss (UHL), assess whether subject‐reported quality of life (QOL) and teacher‐ and parent‐reported perception of listening difficulty are affected by use of a hearing aid (HA) with baseline accommodations, compared to children receiving only baseline accommodations.

Study Design

Randomized crossover clinical trial.

Methods

Thirty‐seven children 6–12 years of age with mild to moderately severe UHL and ≥80% word recognition scores in the poorer hearing ear were randomized into arm 1, using baseline accommodations (frequency‐modulated system and strategic seating) for 12 weeks, followed by addition of a HA for 12 weeks. The other participants were randomized into the reverse methodology: arm 2, using a HA in addition to baseline accommodations for 12 weeks, followed by baseline accommodations alone. Surveys of QOL (Hearing Environments and Reflection on Quality of Life) and listening difficulties or challenges with hearing amplification (CHILD and LIFE‐R questionnaires) were administered at 6‐week intervals. Differences in mean survey scores, percent change, and improvement over time were computed between the two arms and inter‐arm intervals. Per‐protocol analysis was used.

Results

Of the 37 children enrolled, 34 children underwent the study interventions and were included in the analysis, (arm 1 = 20, arm 2 = 14) (mean [standard deviation] age = 8 [1.5] years; 21 boys [61.8%]). Survey scores averaged across both arms during the HA interval (77.79 [15.13]) were significantly higher than during the baseline‐only interval (69.67 [14.69], P = .036). There was no significant difference between trial arms in mean scores between the two HA intervals (P = .450) and two baseline‐only intervals (P = .539).

Conclusions

Hearing‐related QOL and listening ability improved in children who met eligibility criteria with mild to moderately severe UHL with HA use compared with baseline accommodations alone. Trial Registration: ClinicalTrials.gov identifier: NCT02269124.

Level of Evidence

1 Laryngoscope, 132:881–888, 2022
Clinical outcomes of head and neck cancer patients who refuse curative therapy in pursuit of alternative medicine
Authors: Balogh Lauren C. , Matthews T. Wayne , Schrag Christiaan , Elebro Karin A.
Published: August 2021

Background

We investigated the alarming trend of curable head and neck cancer (HNC) patients forgoing conventional treatment to pursue alternative medicine (AM).

Methods

A prospectively maintained database identified HNC patients with ≥12 weeks from diagnosis to treatment initiation between 2012 and 2017. Reasons for delay were categorized and clinical stages and outcomes of AM patients were assessed through chart review by December 2019.

Results

Among 1462 patients with primary HNC, 68 patients (4.7%) were confirmed to delay initiation of potentially curative treatment, and 19 of these patients (28%) delayed treatment to pursue AM. Eleven of 19 AM patients transitioned from curative intent to palliation while exploring AM. Continued treatment rejection was common and outcomes corresponded to patients' degree of treatment adherence.

Conclusions

AM caused treatment delay and poor outcomes in potentially curable HNC. Improved knowledge among physicians regarding AM and complementary approaches is urgently needed to improve patient counseling.

Level of Evidence

Level 2c outcomes research.
Bioremediation of Copper‐Ions by Polymer Encapsulated and Immobilized Micrococcus Luteus
Authors: Mafi Mahsa , Greiner Andreas
Published: August 2021

Bioremediation of copper (Cu2+) with immobilized Micrococcus luteus in polymer matrices has been broadly studied for a wide range of applications including wastewater treatment. Herein, the bioremediation efficiency based on modified immobilization techniques and by the addition of Cu2+ is investigated. Porous composite nonwovens with living M. luteus (living polymer composites) are prepared by encapsulation of the bacterial cells in poly(vinyl alcohol) (PVA) microparticles (M. luteus/PVA microparticles) produced by spray drying method. The M. luteus/PVA microparticles are chemically cross‐linked. The hydrogel microparticles with encapsulated M. luteus are embedded in a nonwoven of poly (lactic acid) (PLA) electrospun short fibers provided by wet‐laid method. Two different models of composite nonwovens are reported, in which the place position of the hydrogel PVA microparticles with encapsulated M. luteus and PLA nonwoven can affect the bioremediation process.
Debate on vaccine mandates leaves mental health providers conflicted
Authors: Enos Gary
Published: August 2021

The resurgence of COVID‐19 cases brought on by the potent Delta variant has left mental health provider organizations facing a dilemma they recently thought they wouldn't have to address: Should they require their staff members to be vaccinated?
Large settlement with insurer signals federal emphasis on enforcing parity
Authors: Enos Gary
Published: August 2021

This month's announcement of more than $15 million in settlement payments from UnitedHealthcare and its behavioral health subsidiary may be less significant for the amount paid than for what this development might signal about stepped‐up monitoring and enforcement of parity compliance.
Study on the spinnability and mechanical properties of aspirator aided melt‐spun binary blends polypropylene fibers
Authors: Qu Muchao , Qin Yijing , Zhu Kai , Schubert Dirk W. , Lu Dong , Wu Siman , Xie Zixin , Han Lei , Gao Qun , Bier Alexander , Du Canyi
Published: August 2021

In this study, polypropylene (PP) binary blends with obviously different molecular weight were produced and melt spun using a capillary rheometer aided with an aspirator for aerodynamic stretching for the first time. A comprehensive processing map on the spinnability of all the seven PP blends regarding to three extrusion speeds and six take‐up pressures was originally presented. According to a detailed investigation on the diameter information and tensile properties of all the PP fibers (modulus, tenacity, elongation at break), the optimum processing parameters of the advanced technology of aspirator for preparing PP fibers were revealed: processing temperature at 250°C, extrusion speed at 0.075 mm/s and take‐up pressure at 1.5 bar. Most importantly, the reliability of a novel mathematic model was verified to predict PP fiber diameters in this study, which provides practical guidance for the research or mass production of PP blend fibers in the academia and industry.
MoS2‐decorated talc hybrid for improving the tribological property of Nomex/PTFE fabric composites
Authors: Li Peilong , Zhang Zhaozhu , Yang Mingming , Yuan Junya , Jiang Wei
Published: August 2021

Producing self‐lubricating fabric composites with excellent wear resistance and long service life is desired for their use in practical application, yet still challenging. Therefore, a novel nanoparticle of talc‐molybdenum sulfide (MoS2) hybrid nanosheets was synthesized via one‐step hydrothermal reaction in this work and incorporated into the Nomex/polytetrafluoroethylene (PTFE) self‐lubricating fabric composites. The spectroscopic and microscopic characterization demonstrated that the talc‐MoS2 nanosheets were successfully synthesized. The talc‐MoS2 nanosheets exhibit the obvious layered structure and covered with MoS2. The effect of talc‐MoS2 hybrid nanosheets on the tribological performance of fabric composites was systematically evaluated by tri‐pin on disk tribometer. The results show that the talc‐MoS2 nanosheets increased the thermal stability, thermal conductivity, tensile strength, and hardness of composite and was favorable for forming high‐quality transfer film on the surface of counterpart pin during the wear process owing to the cooperation effect of talc‐MoS2. The wear rate of talc‐MoS2‐reinforced composite was reduced by 30%–53% under different conditions compared with pure fabric composite.
Striatal GABA level is associated with sensory integration ability in individuals with low levels of negative schizotypy
Authors: Cai Xin‐Lu , Li Gai‐Ying , Wang Ling‐Ling , Zhao Wei‐Wei , Wang Yi , Yan Chao , Lui Simon S. Y. , Li Jian‐Qi , Chan Raymond C. K.
Published: August 2021

Recent studies suggest that altered gamma‐aminobutyric acidergic (GABAergic) function may result in multisensory integration deficits in schizophrenia. However, it is unclear whether the GABA level is abnormal in individuals with high levels of schizotypal traits and how it would correlate with sensory integration ability in these individuals. This study aimed to compare the GABA level between individuals with high and low levels of negative schizotypy, and examine the relationship between GABA levels and sensory integration ability in each group. In vivo GABA+ and N‐acetylaspartate (NAA) levels in the striatum were measured using proton magnetic resonance imaging in 19 participants with high levels of negative schizotypy and 21 participants with low levels of negative schizotypy. The Sensory Integration subscale of the abridged version of the Cambridge Neurological Inventory was used. We examined the group differences in GABA+/NAA levels, and the correlation between striatal GABA+/NAA levels and sensory integration ability in each group. The two groups showed comparable levels of in‐vivo GABA+/NAA. In‐vivo GABA+/NAA levels were negatively correlated with sensory integration score in participants with low levels of negative schizotypy, but not in participants with high levels of negative schizotypy. Our findings indicate that the increased GABA level is correlated with better sensory integration ability in individuals with low levels of negative schizotypy, implicating the role of GABAergic function in multisensory integration. Unlike schizophrenia patients, individuals with high levels of schizotypy do not exhibit any abnormality in their GABAergic system and sensory integration ability.
Raman spectroscopy‐based diagnostics of water deficit and salinity stresses in two accessions of peanut
Authors: Morey Rohini , Farber Charles , McCutchen Bill , Burow Mark D. , Simpson Charles , Kurouski Dmitry , Cason John
Published: August 2021

Water deficit and salinity are two major abiotic stresses that have tremendous effect on crop yield worldwide. Timely identification of these stresses can help limit associated yield loss. Confirmatory detection and identification of water deficit stress can also enable proper irrigation management. Traditionally, unmanned aerial vehicle (UAV)‐based imaging and satellite‐based imaging, together with visual field observation, are used for diagnostics of such stresses. However, these approaches can only detect salinity and water deficit stress at the symptomatic stage. Raman spectroscopy (RS) is a noninvasive and nondestructive technique that can identify and detect plant biotic and abiotic stress. In this study, we investigated accuracy of Raman‐based diagnostics of water deficit and salinity stresses on two greenhouse‐grown peanut accessions: tolerant and susceptible to water deficit. Plants were grown for 76 days prior to application of the water deficit and salinity stresses. Water deficit treatments received no irrigation for 5 days, and salinity treatments received 1.0 L of 240‐mM salt water per day for the duration of 5‐day sampling. Every day after the stress was imposed, plant leaves were collected and immediately analyzed by a hand‐held Raman spectrometer. RS and chemometrics could identify control and stressed (either water deficit or salinity) susceptible plants with 95% and 80% accuracy just 1 day after treatment. Water deficit and salinity stressed plants could be differentiated from each other with 87% and 86% accuracy, respectively. In the tolerant accessions at the same timepoint, the identification accuracies were 66%, 65%, 67%, and 69% for control, combined stresses, water deficit, and salinity stresses, respectively. The high selectivity and specificity for presymptomatic identification of abiotic stresses in the susceptible line provide evidence for the potential of Raman‐based surveillance in commercial‐scale agriculture and digital farming.
Nutrition and growth in infants with established bronchopulmonary dysplasia
Authors: Bauer Sarah E. , Vanderpool Charles P. B. , Ren Clement , Cristea Aura Ioana
Published: August 2021

Bronchopulmonary dysplasia (BPD) remains the most common late morbidity of preterm birth. Ongoing clinical care and research have largely focused on the pathogenesis and prevention of BPD in preterm infants. However, preterm infants who develop BPD have significant medical needs that persist throughout their neonatal intensive care unit course and continue post‐discharge, including those associated with growth and nutrition. The objective of this manuscript was to provide a review on nutrition and growth in infants with established BPD after discharge from the hospital and to identify the knowledge and research gaps to provide direction for future studies.
How a Conformally Flat Impacts Gauss‐Bonnet Gravity?
Authors: De Avik , Loo Tee‐How , Solanki Raja , Sahoo P.K.
Published: August 2021

First and foremost, we show that a 4‐dimensional conformally flat generalized Ricci recurrent spacetime is an Einstein manifold. We examine such a spacetime as a solution of ‐gravity theory and it is shown that the additional terms from the modification of the gravitational sector can be expressed as a perfect fluid. Several energy conditions are investigated with and . For both the models, weak, null and dominant energy conditions are satisfied while strong energy condition is violated, which is a good agreement with the recent observational studies which reveals that the current universe is in accelerating phase.
Evolutionary and structural constraints influencing apolipoprotein A‐I amyloid behavior
Authors: Gisonno Romina A. , Masson Tomas , Ramella Nahuel A. , Barrera Exequiel E. , Romanowski Víctor , Tricerri M. Alejandra
Published: August 2021

Apolipoprotein A‐I (apoA‐I) has a key function in the reverse cholesterol transport. However, aggregation of apoA‐I single point mutants can lead to hereditary amyloid pathology. Although several studies have tackled the biophysical and structural consequences introduced by these mutations, there is little information addressing the relationship between the evolutionary and structural features that contribute to the amyloid behavior of apoA‐I. We combined evolutionary studies, in silico mutagenesis and molecular dynamics (MD) simulations to provide a comprehensive analysis of the conservation and pathogenic role of the aggregation‐prone regions (APRs) present in apoA‐I. Sequence analysis demonstrated that among the four amyloidogenic regions described for human apoA‐I, only two (APR1 and APR4) are evolutionary conserved across different species of Sarcopterygii. Moreover, stability analysis carried out with the FoldX engine showed that APR1 contributes to the marginal stability of apoA‐I. Structural properties of full‐length apoA‐I models suggest that aggregation is avoided by placing APRs into highly packed and rigid portions of its native fold. Compared to silent variants extracted from the gnomAD database, the thermodynamic and pathogenic impact of amyloid mutations showed evidence of a higher destabilizing effect. MD simulations of the amyloid variant G26R evidenced the partial unfolding of the alpha‐helix bundle with the concomitant exposure of APR1 to the solvent, suggesting an insight into the early steps involved in its aggregation. Our findings highlight APR1 as a relevant component for apoA‐I structural integrity and emphasize a destabilizing effect of amyloid variants that leads to the exposure of this region.
Rapid‐Thermal‐Annealing‐Induced Passivation Degradation and Recovery of Polysilicon Passivated Contact with Czochralski and Cast Multicrystalline Silicon Substrates
Authors: Feng Mengmeng , Zeng Yuheng , Yang Zhenhai , Liao Mingdun , Zheng Jingming , Zhi Yuyan , Lin Yiran , Lu Linna , Chen Huanhuan , Yang Jie , Zhang Xinyu , Jin Hao , Hou Hongying , Yan Baojie , Ye Jichun
Published: August 2021

Metallization of high‐efficiency n‐type solar cells with tunnel oxide passivated contact (TOPCon) structures often requires a high‐temperature rapid‐thermal‐annealing (RTA) process, which potentially induces a notable degradation of device performance. Herein, the RTA‐induced passivation degradation mechanisms and potential recovery processes are clarified by postthermal annealing or hydrogenation based on both Czochralski (Cz) silicon and cast‐multicrystalline (cast‐mc) silicon wafers. It is found that the RTA process induces at least two kinds of defects, i.e., thermal‐quenching‐induced defects and hydrogen‐release‐induced defects. The passivation quality can be partially recovered under a high‐temperature annealing at 820 °C, which, however, can be fully restored via a postmoisture/nitrogen hydrogenation treatment at 450 °C. In general, the two mentioned wafers, i.e., n‐type Cz c‐Si and cast‐mc silicon substrates, demonstrate similar passivation behaviors in most cases before and after RTA treatment. Finally, it is inferred that the inferior passivation properties of the n‐type cast‐mc silicon samples are related to the relatively low bulk quality. This can be confirmed by the fact that samples with n‐type cast‐mc Si substrates show an abnormal passivation behavior with highly effective lifetimes in the low‐density carrier region, suggesting the existence of electron trapping states.
Randomised preconditioning for the forcing formulation of weak‐constraint 4D‐Var
Authors: Daužickaitė Ieva , Lawless Amos S. , Scott Jennifer A. , van Leeuwen Peter Jan
Published: August 2021

There is growing awareness that errors in the model equations cannot be ignored in data assimilation methods such as four‐dimensional variational assimilation (4D‐Var). If allowed for, more information can be extracted from observations, longer time windows are possible, and the minimisation process is easier, at least in principle. Weak‐constraint 4D‐Var estimates the model error and minimises a series of quadratic cost functions, which can be achieved using the conjugate gradient (CG) method; minimising each cost function is called an inner loop. CG needs preconditioning to improve its performance. In previous work, limited‐memory preconditioners (LMPs) have been constructed using approximations of the eigenvalues and eigenvectors of the Hessian in the previous inner loop. If the Hessian changes significantly in consecutive inner loops, the LMP may be of limited usefulness. To circumvent this, we propose using randomised methods for low‐rank eigenvalue decomposition and use these approximations to construct LMPs cheaply using information from the current inner loop. Three randomised methods are compared. Numerical experiments in idealized systems show that the resulting LMPs perform better than the existing LMPs. Using these methods may allow more efficient and robust implementations of incremental weak‐constraint 4D‐Var.
Dynamic event‐triggered communication based distributed optimization
Authors: Zhang Zhiqiang , Lunze Jan , Sun Yuangong , Lu Zehuan
Published: August 2021

This article presents distributed continuous‐time algorithms with dynamic event‐triggered communication, called the dynamic event‐triggered algorithms, to solve a convex optimization problem in a multiagent network. Firstly, a new dynamic event‐triggered communication scheme is introduced and it is shown that the optimization problem is solved and occurrence of Zeno behavior is prevented. Secondly, under the dynamic event‐triggered communication implementations, both uniform and logarithmic quantized information algorithms are given to solve the optimization problem. Finally, numerical simulations are given to illustrate the effectiveness of the derived results.
Adhesive bond integrity of Y‐TZP post with calcium fluoride infiltrated resin dentin adhesive: An SEM, EDX, FTIR and micro‐Raman study
Authors: AlHamdan Eman M. , Al‐Saleh Samar , AlRefeai Mohammad H. , Farooq Imran , Abrar Eisha , Vohra Fahim , Abduljabbar Tariq
Published: August 2021

The study aimed to synthesize calcium fluoride (CaF2) nanoparticles and compare the push‐out bond strength and viscosity of experimental adhesive (EA) and EA with 5 wt.% CaF2 (CAF‐5%). The CaF2 nanoparticles were synthesized and then characterized with scanning electron microscopy (SEM)‐energy‐dispersive X‐ray spectroscopy (EDX), Fourier transform infrared (FTIR), and micro‐Raman spectroscopies. CaF2 nanoparticles were incorporated in the adhesives to yield two groups; gp‐1: EA‐CAF‐0% (control) and gp‐2: CAF‐5%. Canals of 20 teeth (N = 20) were prepared, and then yttria‐stabilized tetragonal zirconia polycrystalline (Y‐TZP) ceramic posts were cemented. Adhesives were assessed for push‐out bond strength and rheology. CaF2 filler was seen as irregularly shaped agglomerates on SEM. The EDX analysis demonstrated the presence of calcium and fluoride for the CAF‐5% group. The FTIR indicated characteristic bands for CaF2 containing materials. The micro‐Raman spectra of CaF2 nanoparticles demonstrated the presence of CaF2 by showing strong bands at 840 cm−1, 1380 cm‐1, and 1400 cm−1 for fluorine and 950 cm−1 and 1080 cm−1 for calcium ions. The highest push‐out bond strength values were obtained for CAF‐5% group samples (cervical: 9.67 ± 1.46 MPa, apical: 8.66 ± 1.24 MPa), and both adhesives revealed adhesive‐dentin interfacial fractures. The CAF‐5% adhesive also revealed comparable rheological properties with the controls. The addition of CaF2 nanoparticles in the adhesive improved its push‐out bond strength to Y‐TZP post and root dentin, although CAF‐5% showed reduced viscosity on rheological assessment (compared with the controls).
The myth of the flat start‐up: Reconsidering the organizational structure of start‐ups
Authors: Lee Saerom (Ronnie)
Published: August 2021

Research summary

There has been an ongoing debate over whether start‐ups should be “flat” with minimal hierarchical layers. To reconcile this debate, this article distinguishes between creative and commercial success (i.e., novelty vs. profitability), and examines how these outcomes are variously influenced by a start‐up's hierarchy. This study suggests that while a flatter hierarchy can improve ideation and creative success, it can result in haphazard execution and commercial failure by overwhelming managers with the burden of direction and causing subordinates to drift into power struggles and aimless idea explorations. I find empirical support for this trade‐off using a large sample of game development start‐ups. These findings offer one resolution to the debate by sorting out the conditions under which hierarchy can be conducive or detrimental to start‐ups.

Managerial summary

Academics, management gurus, and popular media outlets have argued that “authoritarian,” tall hierarchies are outmoded and will be supplanted by “egalitarian,” flat structures. In recent years, this argument has been largely substantiated by a few “successful” flat start‐ups, such as Valve, Zappos, Github, Medium, and Buffer. As these nascent firms constantly garner much attention for their egalitarian ideal—which itself is a signal of their rarity—the myth that start‐ups should be flat (often referred to as “flat organization,” “holacracy,” or “boss‐less firm”) has become widespread among entrepreneurs. My study cautions against this myth, suggesting that adding a few hierarchical levels of managers can substantially help start‐ups achieve commercial success and survive in their hostile environments, albeit at a potentially marginal cost of creativity.
Two Decades of Progress in the Asymmetric Intramolecular aza‐Michael Reaction
Authors: Sánchez‐Roselló María , Escolano Marcos , Gaviña Daniel , del Pozo Carlos
Published: August 2021

The asymmetric intramolecular aza‐Michael reaction (IMAMR) is a very convenient strategy for the generation of heterocycles bearing nitrogen‐substituted stereocenters. Due to the ubiquitous presence of these skeletons in natural products, the IMAMR has found widespread applications in the total synthesis of alkaloids and biologically relevant compounds. The development of asymmetric versions of the IMAMR are quite recent, most of them reported in this century. The fundamental advances in this field involve the use of organocatalysts. Chiral imidazolidinones, diaryl prolinol derivatives, Cinchone‐derived primary amines and quaternary ammonium salts, and BINOL‐derived phosphoric acids account for the success of those methodologies. Moreover, the use of N‐sulfinyl imines with a dual role, as nitrogen nucleophiles and as chiral auxiliaries, appeared as a versatile mode of performing the asymmetric IMAMR.