bluuebunny/crossref_metadata_2025 huggingface dataset:
Triple-shelled CuO/CeO2 hollow nanospheres derived from metal–organic frameworks as highly efficient catalysts for CO oxidation
Authors: Song Xue-Zhi , Su Qiao-Feng , Li Shao-Jie , Liu Si-Hang , Zhang Nan , Meng Yu-Lan , Chen Xi , Tan Zhenquan
Published: September 2019

Through a metal–organic framework engaged strategy, triple-shelled CuO/CeO2-8% hollow nanospheres are fabricated as superior nanocatalysts for CO oxidation with excellent catalytic activity and cyclic stability.
Recent progress on the total syntheses of macrocyclic diamine alkaloids
Authors: Cheng Bichu , Reyes Julius
Published: September 2019

This review highlights the progress and challenges in the chemical synthesis of macrocyclic diamine alkaloids since 2006.
Lifetime-tunable room-temperature phosphorescence of polyaniline carbon dots in adjustable polymer matrices
Authors: Gou Huilin , Liu Yanfeng , Zhang Guiyang , Liao Qiaobo , Huang Xin , Ning Fangyi , Ke Can , Meng Zhen , Xi Kai
Published: September 2019

A series of room-temperature composites were synthesized by embedding polyaniline carbon dots in hydrogen-bonded polymer matrices. Adjustable RTP lifetime are realized, enabling time-resolved anti-counterfeit and data encryption patterns.
Neurotransmitter selection by monoamine oxidase isoforms, dissected in terms of functional groups by mixed double mutant cycles
Authors: Hudspith L. , Shmam F. , Dalton C. F. , Princivalle A. , Turega S. M.
Published: September 2019

Double mutant cycles were constructed using neurotransmitters and synthetic substrates that measure their selective binding to one monoamine oxidase (MAO) enzyme isoform over another as a function of structural change.
Rapid construction of tetrahydropyridine scaffolds via formal imino Diels–Alder reactions of Schiff bases and Nazarov reagents
Authors: Wu Yen-Ku , Rawal Viresh H.
Published: September 2019

A collection of piperidine derivatives including tetrabenazine was synthesized via aza-annulation of Nazarov reagents and Schiff bases in protic solvents.
Synthesis and supramolecular liquid crystalline structure modulation of side-chain polynorbornenes with asymmetrical substituent mesogenic groups
Authors: Tu Yuanyang , Wu Yijin , Pei Jiwei , Qu Wentao , Lu Huanjun , Liu Feng , Chen Xiao-Fang
Published: September 2019

The substituent position and number have an important effect on the supramolecular liquid crystalline structure evolution in side-chain polymers.
Time-dependent shear rate inhomogeneities and shear bands in a thixotropic yield-stress fluid under transient shear
Authors: Wei Yufei , Solomon Michael J. , Larson Ronald G.
Published: September 2019

We study the rheological responses and shear-rate inhomogeneities and shear banding behaviors of a thixotropic fumed silica suspension in shear startup tests and flow reversal tests.
Centrosomal cohesion deficits as cellular biomarker in lymphoblastoid cell lines from LRRK2 Parkinson's disease patients
Authors: Fernández Belén , Lara Ordóñez Antonio Jesús , Fdez Elena , Mutez Eugénie , Comptdaer Thomas , Leghay Coline , Kreisler Alexandre , Simonin Clémence , Vandewynckel Laurine , Defebvre Luc , Destée Alain , Bleuse Séverine , Taymans Jean-Marc , Chartier-Harlin Marie-Christine , Hilfiker Sabine
Published: September 2019

Leucine-rich repeat kinase 2 (LRRK2) is a promising therapeutic target for the treatment of Parkinson's disease (PD), and orally bioavailable, brain penetrant and highly potent LRRK2 kinase inhibitors are in early stages of clinical testing. Detection of LRRK2 phosphorylation, as well as phosphorylation of Rab10, a LRRK2 kinase substrate, have been proposed as target engagement biomarkers for LRRK2 inhibitor clinical trials. However, these readouts do not seem able to stratify patients based on enhanced LRRK2 kinase activity. Here, we describe a robust cell biological assay based on centrosomal cohesion alterations which were observed in peripheral blood mononuclear cell-derived lymphoblastoid cell lines (LCLs) from patients with G2019S LRRK2 mutations as compared with healthy controls, and could also be detected in a subset of sporadic PD patient samples. We suggest that LCLs may be a valuable resource for LRRK2 research, and that determination of centrosomal cohesion deficits may assist in the stratification of a subset of sporadic PD patients.
Rhyme Production Strategies Distinguish Stuttering Recovery and Persistence
Authors: Gerwin Katelyn , Brosseau-Lapré Françoise , Brown Barbara , Christ Sharon , Weber Christine
Published: September 2019

Purpose

The primary aim of the current study was to examine the developing phonological awareness of 4- to 5-year-old children who stutter (CWS) in relation to eventual recovery (CWS-eRec) or persistance (CWS-ePer) in stuttering, accounting for the presence of typical speech (TS) production or speech sound disorder (SSD).

Method

In the 1st year of a 5-year longitudinal study, 37 children who do not stutter (CWNS) and 48 CWS completed a rhyme discrimination and a rhyme production task from the Phonological Awareness Test–Second Edition (
Robertson & Salter, 2007
). Using data from their last year of participation, CWS were classified into CWS-ePer and CWS-eRec. Each CWS group was further divided into TS and SSD groups based on speech production abilities at the time of the rhyme tasks. Accuracy on the rhyme tasks was compared. Groups were also compared on strategies used to generate correct and incorrect responses for the rhyme production task (e.g., real-word correct, nonword correct, semantic association, repeated cues).

Results

All groups performed similarly on the rhyme discrimination task. On the rhyme production task, CWS-ePer-SSD and CWS-eRec-SSD performed with less accuracy than CWNS, but CWS-ePer-TS, CWS-eRec-TS, and CWNS achieved similar task accuracy. On correct rhyme production trials, CWS-ePer-TS created more nonword rhymes than real-word rhymes. CWS-ePer-TS used the nonword strategy at 1.88 times the CWNS rate. CWS-eRec-TS fell between CWS-ePer-TS and CWNS in use of the nonword strategy.

Conclusions

Reliance on a nonword strategy for rhyme production in CWS-ePer-TS may reflect differences in underlying phonological representations and ease of phonological access to the lexicon compared to CWNS.
Objective Intelligibility Assessment by Automated Segmental and Suprasegmental Listening Error Analysis
Authors: Jiao Yishan , LaCross Amy , Berisha Visar , Liss Julie
Published: September 2019

Purpose

Subjective speech intelligibility assessment is often preferred over more objective approaches that rely on transcript scoring. This is, in part, because of the intensive manual labor associated with extracting objective metrics from transcribed speech. In this study, we propose an automated approach for scoring transcripts that provides a holistic and objective representation of intelligibility degradation stemming from both segmental and suprasegmental contributions, and that corresponds with human perception.

Method

Phrases produced by 73 speakers with dysarthria were orthographically transcribed by 819 listeners via Mechanical Turk, resulting in 63,840 phrase transcriptions. A protocol was developed to filter the transcripts, which were then automatically analyzed using novel algorithms developed for measuring phoneme and lexical segmentation errors. The results were compared with manual labels on a randomly selected sample set of 40 transcribed phrases to assess validity. A linear regression analysis was conducted to examine how well the automated metrics predict a perceptual rating of severity and word accuracy.

Results

On the sample set, the automated metrics achieved 0.90 correlation coefficients with manual labels on measuring phoneme errors, and 100% accuracy on identifying and coding lexical segmentation errors. Linear regression models found that the estimated metrics could predict a significant portion of the variance in perceptual severity and word accuracy.

Conclusions

The results show the promising development of an objective speech intelligibility assessment that identifies intelligibility degradation on multiple levels of analysis.
The s process in rotating low-mass AGB stars
Authors: den Hartogh J. W. , Hirschi R. , Lugaro M. , Doherty C. L. , Battino U. , Herwig F. , Pignatari M. , Eggenberger P.
Published: September 2019

Aims. We investigate the s-process during the AGB phase of stellar models whose cores are enforced to rotate at rates consistent with asteroseismology observations of their progenitors and successors.

Methods. We calculated new 2 M⊙, Z = 0.01 models, rotating at 0, 125, and 250 km s−1 at the start of main sequence. An artificial, additional viscosity was added to enhance the transport of angular momentum in order to reduce the core rotation rates to be in agreement with asteroseismology observations. We compared rotation rates of our models with observed rotation rates during the MS up to the end of core He burning, and the white dwarf phase.

Results. We present nucleosynthesis calculations for these rotating AGB models that were enforced to match the asteroseismic constraints on rotation rates of MS, RGB, He-burning, and WD stars. In particular, we calculated one model that matches the upper limit of observed rotation rates of core He-burning stars and we also included a model that rotates one order of magnitude faster than the upper limit of the observations. The s-process production in both of these models is comparable to that of non-rotating models.

Conclusions. Slowing down the core rotation rate in stars to match the above mentioned asteroseismic constraints reduces the rotationally induced mixing processes to the point that they have no effect on the s-process nucleosynthesis. This result is independent of the initial rotation rate of the stellar evolution model. However, there are uncertainties remaining in the treatment of rotation in stellar evolution, which need to be reduced in order to confirm our conclusions, including the physical nature of our approach to reduce the core rotation rates of our models, and magnetic processes.
Spectral imaging of the thermal Sunyaev–Zel’dovich effect in X-COP galaxy clusters: method and validation
Authors: Baldi A. S. , Bourdin H. , Mazzotta P. , Eckert D. , Ettori S. , Gaspari M. , Roncarelli M.
Published: September 2019

The imaging of galaxy clusters through the Sunyaev–Zel’dovich effect is a valuable tool to probe the thermal pressure of the intra-cluster gas, especially in the outermost regions where X-ray observations suffer from photon statistics. For the first time, we produce maps of the Comptonization parameter by applying a locally parametric algorithm for sparse component separation to the latest frequency maps released byPlanck. The algorithm takes into account properties of real cluster data through the two-component modelling of the spectral energy density of thermal dust, and the masking of bright point sources. Its robustness has been improved in the low signal-to-noise regime, thanks to the implementation of a deconvolution ofPlanckbeams in the chi-square minimisation of each wavelet coefficient. We applied this procedure to twelve low-redshift galaxy clusters detected byPlanckwith the highest signal-to-noise ratio, considered in the XMM Cluster Oustkirts Project (X-COP). Our images show the presence of anisotropic features, such as small-scale blobs and filamentary substructures that are located in the outskirts of a number of clusters in the sample. The significance of their detection is established via a bootstrap-based procedure we propose here for the first time. In particular, we present a qualitative comparison with X-ray data for two interesting systems, namely A2029 and RXCJ1825. Our results are in agreement with the features detected in the outskirts of the clusters in the two bands.
Obstruktive Lungenerkrankungen im Kindesalter
Authors: Tenbrock Klaus
Published: September 2019

Obstruktive Lungenerkrankungen gehören zu den häufigsten Erkrankungen im Kindesalter überhaupt und umfassen ein ganzes Spektrum von Entitäten. Differenzialdiagnosen, Pathogenese, Diagnostik und Therapiemöglichkeiten von der Bronchiolitis im frühen Säuglingsalter über obstruktive Bronchitiden bei Kleinkindern bis hin zum großen Thema Asthma bronchiale, dies alles stellt dieser Beitrag kompakt vor.
A Systematic Review on the Value of Infrared Thermography in the Early Detection of Periprosthetic Joint Infections
Authors: Scheidt Sebastian , Rüwald Julian , Schildberg Frank Alexander , Mahlein Anne Katrin , Seuser Axel , Wirtz Dieter Christian , Jacobs Cornelius
Published: September 2019

Background Variations in the temperature of body and skin are symptoms of many pathological changes. Although joint replacement surgery of hip and knee has been very successful in recent decades, periprosthetic infection is a growing problem and the number one reason for revision. While many studies have investigated changes in blood levels, investigation of temperature has not been performed on a regular basis. The objective of this work is to determine whether reference literature exists for the infrared thermographic examination in knee and hip arthroplasty and if reference values can be derived for the methodology or if there is a peri- and postoperative benefit.

Material und Methods By means of a systematic online database search and based on the Cochrane, PICOT and PRISMA guidelines, this systematic review retrieved 254 studies. All publications with thermographic examination in arthroplasty of the hip and knee were imbedded. 249 studies were excluded due to the defined inclusion and exclusion criteria and five studies with 251 patients have finally been included in the evaluation process. This was followed by an analysis and discussion of the methodology.

Results and Conclusion Infrared thermography is a useful tool in the perioperative care of patients after arthroplasty of the knee and hip joint. The technology is portable, easy to use and non-invasive. Based only on these few publications, values can be derived, which provide a guidance for the thermographic aftercare in arthroplasty surgery.
Clinical Study of Bell's Palsy at Tertiary Care: Our Experience
Authors: Bharathi M. B. , Unisa Thanzeem , Chandresh Swathi , R. Venkatesh C. , S. Harsha
Published: September 2019

Introduction Bell's palsy (BP) is the common cause of facial palsy. This study aims to report and analyze the age, sex distribution, symptomatology, site of lesion, and prognosis in 101 patients with (BP).

Materials and Methods This is a cross-sectional study conducted at tertiary referral center, JSS Hospital, Mysuru. All patients consenting to participate in this study, of all ages, of either sex, both outpatients and inpatients with a diagnosis of BP during this study period were included.

Results Of the 101 patients analyzed, maximum cases (25.7%) were in third decade of age; 55.4% were males, and both right and left sides of the face were equally involved. Maximum number of patients (50.5%) had a history of postaural pain at presentation Topodiagnostic tests showed majority of BP cases involving geniculate or suprageniculate regions (67.3%) in our study. 20.8% had lesion above the nerve to stapedius, and 11.9% had lesion below the nerve to stapedius. Electrodiagnostic test—electroneuromyography (ENMG)—was abnormal in 57 (67.1%) individuals at day 4. 50.4% of patients had a House-Brackmann (HB) facial nerve grade IV at presentation. 90% of the BP group in our study recovered normal to near-normal facial nerve function by the end of 28 days’ time.

Conclusion Each case of BP should be evaluated with thorough clinical examination, topodiagnostic tests, and electrodiagnostic tests. Appropriate management will help in almost full recovery of disease.
Pneumothorax—Time for New Guidelines?
Authors: Hallifax Rob , Janssen Julius P.
Published: September 2019

Pneumothorax is a common pathology, but optimal management strategies are not yet defined. There are significant differences in international guidelines and therefore variation in clinical practice.

There is increasing interest in pneumothorax research, particularly primary spontaneous pneumothorax (PSP), with evidence of lung abnormalities in this group without clinically apparent lung disease and recently completed clinical trials aiming to optimize management. The most robust evidence base is that of the equivalence of needle aspiration and chest tube insertion for initial management of PSP; although, patients with secondary spontaneous pneumothorax may also benefit. A convincing case for surgical intervention or thoracoscopy and talc poudrage to prevent recurrence at first episode in PSP has yet to be made. Clinicians should be vigilant for PSP being the first manifestation of a systemic disease, and should have a low threshold for onward referral.

Time to change guidelines? First, chest tube drainage and hospitalization without recurrence prevention should no longer be standard treatment, as this has no advantage over the less invasive manual aspiration, which moreover can be performed on an outpatient basis in an important number of patients. The results of recent trials in conservative and ambulatory management are eagerly awaited. Second, shared decision-making should become more important with the well-informed patient, who may want to avoid a 1 in 3 recurrence rate and therefore will have the possibility to choose treatment including recurrence prevention even after the first episode of PSP. Third, surgical research should urgently make clear if the current practice of resection of emphysema-like changes is routinely necessary, alongside pleurodesis. Future studies should utilize risk stratification by clinical and radiological parameters (e.g., high-resolution computed tomography scanning and digital air leak monitoring) to predict short- and long-term outcomes, and hence personalize management.
Objective Assessment of Microsurgery Competency—In Search of a Validated Tool
Authors: Rajan Sheeja , Sathyan Ranjith , Sreelesh L. S. , Kallerey Anu Anto , Antharjanam Aarathy , Sumitha Raj , Sundar Jinchu , John Ronnie Johnson , Soumya S.
Published: September 2019

Microsurgical skill acquisition is an integral component of training in plastic surgery. Current microsurgical training is based on the subjective Halstedian model. An ideal microsurgery assessment tool should be able to deconstruct all the subskills of microsurgery and assess them objectively and reliably. For our study, to analyze the feasibility, reliability, and validity of microsurgery skill assessment, a video-based objective structured assessment of technical skill tool was chosen. Two blinded experts evaluated 40 videos of six residents performing microsurgical anastomosis for arteriovenous fistula surgery. The generic Reznick's global rating score (GRS) and University of Western Ontario microsurgical skills acquisition/assessment (UWOMSA) instrument were used as checklists. Correlation coefficients of 0.75 to 0.80 (UWOMSA) and 0.71 to 0.77 (GRS) for interrater and intrarater reliability showed that the assessment tools were reliable. Convergent validity of the UWOMSA tool with the prevalidated GRS tool showed good agreement. The mean improvement of scores with years of residency was measured with analysis of variance. Both UWOMSA (p-value: 0.034) and GRS (p-value: 0.037) demonstrated significant improvement in scores from postgraduate year 1 (PGY1) to PGY2 and a less marked improvement from PGY2 to PGY3. We conclude that objective assessment of microsurgical skills in an actual clinical setting is feasible. Tools like UWOMSA are valid and reliable for microsurgery assessment and provide feedback to chart progression of learning. Acceptance and validation of such objective assessments will help to improve training and bring uniformity to microsurgery education.
Narcotic-Free Perioperative Total Knee Arthroplasty: Does the Periarticular Injection Medication Make a Difference?
Authors: Schneider J. , Broome B. , Keeley D.
Published: September 2019

Multimodal pain management strategies are critical in total knee arthroplasty (TKA). There has recently been a shift toward opioid sparing protocols, yet most publications continue to use narcotics in the perioperative period. Periarticular injections are a popular adjunct but studies regarding the optimal medications have high variability making it difficult to choose the optimal medication. The purpose of this study is to validate a perioperative, opioid-free protocol and compare two different periarticular injections without the variability in previous reports. A multimodal pain protocol was instituted that administered no narcotic medications in the perioperative period. Over 2 years, primary TKA patients were informally randomized to receive liposomal bupivacaine (LB), or a cocktail of medications (CO). A total of 189 patients were included: 101 patients in group LB and 88 patients in group CO. Postoperative opioid consumption, length of stay, and inpatient distance ambulated were compared across the two injection groups. In morphine milligram equivalents, group LB consumed a mean of 20.36 mg of oxycodone versus 23.18 mg in group CO (p = 0.543). For tramadol, group LB consumed 27.24 mg versus 28.69 mg in group CO (p = 0.714). Mean hospital stay was 1.70 days for group LB and 1.72 days for group CO (p = 0.811). Distance ambulated was 528.4ft for group LB and 499.8ft for group CO (p = 0.477). In the LB group, 50% of patients required no oxycodone, and 12% of them took neither oxycodone nor tramadol for pain. In the CO group, 40% declined oxycodone and 10% declined both oxycodone and tramadol. We successfully treated all patients without narcotic medications in the perioperative period. Although we saw trends for improvements in group LB, these were small and not clinically meaningful. It appears that both injections were effective. There is a significant cost difference and medications should be chosen based on surgeon preference and institutional needs.
Clinical Characteristics, Acute Complications, and Neurologic Outcomes of Salmonella Meningitis in Saudi Infants and Children
Authors: Alsubaie Sarah , Alrabiaah Abdulkarim
Published: September 2019

Objective This study aimed to clarify the clinical presentations, acute complications, and long-term sequelae of Salmonella meningitis in Saudi infants and children.

Methods This retrospective study, conducted from 1999 to 2016, evaluated the neurological complications and long-term outcomes of children 14 years of age and younger diagnosed with Salmonella meningitis at King Khalid University Hospital. All affected children had 3 years of follow-up to assess neurologic complications and mortality.

Results Invasive Salmonella infection occurred in 141 patients. Of those, 14 (10%) had meningitis. The median age of onset of infection was 4.7 months. The most frequent symptoms at presentation included fever (100%), seizures (71%), diarrhea, and vomiting (43%). Nontyphoidal Salmonella species were isolated in all (but one) cerebrospinal fluid samples. Relapse occurred in four patients owing to inadequate antibiotic duration, although the organisms were susceptible to ceftriaxone. The majority of patients (86%) developed acute neurologic complications, including subdural empyema and multiple cerebral infarcts (57%), hydrocephalus (36%), ventriculitis (29%), and cerebral venous sinus thrombosis (21%). Four patients (28.5%) died due to Salmonella meningitis complications. Four patients survived with full recovery. Six patients (60%) had long-term neurologic complications. Hydrocephalus, cerebral palsy, developmental delay, and epilepsy occurred in five, four, three, and three patients, respectively.

Conclusion Salmonella meningitis results in significant mortality and adverse neurodevelopmental outcomes. The probability of relapse after an apparent recovery should be considered. Consensus on antibiotic treatment for Salmonella meningitis is needed.
A2DS2 Score to Predict the Risk of Stroke-Associated Pneumonia in Acute Stroke: An Indian Perspective
Authors: Vyas Limesh , Kulshreshtha Dinkar , Maurya Pradeep , Singh Ajai , Qavi Abdul , Thacker Anup
Published: September 2019

Background Stroke-associated pneumonia (SAP) is an important cause of poststroke morbidity and mortality. Several clinical risk scores predict the risk of SAP. In this study, we used the A2DS2 score (age, atrial fibrillation, dysphagia, sex, and stroke severity) to assess the risk of SAP in patients admitted with acute stroke.

Methods A high (5–10) and a low (0–4) A2DS2 score was assigned to patients with acute stroke admitted to the neurology ward. Univariate binary logistic regression analysis was performed to find the strength of association of SAP and A2DS2 score.

Results There were 250 patients with acute stroke of which 46 developed SAP. Forty-four patients developed SAP in high score as against 2 in low-score group (odds ratio [OR] = 0.03, 95% confidence interval [CI] = 0.01–0.15, p = 0.0001). A2DS2 score >5 had sensitivity of 82.6% and specificity of 65.1% to predict SAP. The mean A2DS2 score in patients with pneumonia was 7.02 ± 1.40 compared to 4.75 ± 1.92 in patients without pneumonia (p = 0.0001).

Conclusions A2DS2 score has a high sensitivity of 82% in predicting the risk of SAP and is a useful tool to monitor patients after acute stroke. A2DS2 score can help in timely detection and prevention of SAP and reduction in caregiver’s burden.
Multifractal analysis to study break points in temperature data sets
Authors: García-Marín A. P. , Estévez J. , Alcalá-Miras J. A. , Morbidelli R. , Flammini A. , Ayuso-Muñoz J. L.
Published: September 2019

Since the last century, the air surface temperature has increased at a global scale, showing trends and inhomogeneities that vary from place to place. Many statistical methods can be used to analyze whether or not an inhomogeneity or break point exists in a meteorological data series, and even to detect the time of the break. Sometimes, there is no agreement in the year at which the inhomogeneity occurs detected by different tests. The scale invariance of a process can be studied through its multifractal properties that can be related to the existence of break points in it. In this work, the multifractal properties of monthly temperature data series are used to test what is the right break point year in those situations at which different dates are found by two different tests: the Pettitt and the Standard Normal Homogeneity tests. The comparison of the fractal dimension function Dq and the multifractal spectrum obtained by the box counting method for both the original data sets and for those obtained by splitting the original into two considering the break point years was made. When different multifractal functions and parameters were obtained, a break point was confirmed. Whereas, if equal values appeared, the break point year was discarded. These results let to select the most suitable test to be applied to detect inhomogeneities in a certain data set that will be very useful for climate change studies.
Modulating relaxation responses of magnetic nanotracers for submillimeter imaging
Authors: Trisnanto Suko Bagus , Takemura Yasushi
Published: September 2019

Frequency-dependent magnetization characteristics potentially promote magnetic nanoparticles as prominent nanotracers for tomographic imaging. Owing to fast Neel dynamics relative to Brownian rotation of colloidal magnetic nanoparticles, we can demonstrate a two-dimensional image reconstruction from the Néel and Brownian relaxation responses modulated by external oscillatory field bursts with two distinctive frequencies. To realize a micrometer-scale resolution, a field-free-point (FFP) is manipulated to move in a dense Lissajous trajectory by low-frequency perpendicular sinusoidal fields across a steep field gradient between two permanent magnets. Instead of directly recording the resulting harmonic responses, we use an orthogonal high-frequency field to probe the time-varying FFP movement coupled with the moment relaxation. The proposed method achieves high spatial resolution, irrespective of the nonlinearity of the magnetization response, making it practical for bioanalytical imaging of cells and small animal models.
Monitoring of singlet fission via two-dimensional photon-echo and transient-absorption spectroscopy: Simulations by multiple Davydov trial states
Authors: Sun Kewei , Huang Zhongkai , Gelin Maxim F. , Chen Lipeng , Zhao Yang
Published: September 2019

Employing the Dirac-Frenkel time dependent variational method, the nonlinear spectra monitoring the singlet fission process mediated by a conical intersection (CI) of the two lowest excited electronic states are investigated for different optical dephasings. The simulated two-dimensional spectra at different population times follow ultrafast population transfer through the CI and exhibit spectral features related to the tuning mode. The anticorrelated oscillations of cross peaks located at symmetric positions with respect to the main diagonal are clearly identified after the stimulated-emission contribution quenches. The simulated transient absorption signals show a fast decay of the first excited singlet state and exhibit multiple peaks revealing the tuning mode. These findings could be regarded as signatures of the CI in the singlet fission process.
Understanding the importance of the energetics of Mn, Ni, Cu, Si and vacancy triplet clusters in bcc Fe
Authors: Whiting T. M. , Burr P. A. , King D. J. M. , Wenman M. R.
Published: September 2019

Numerous experimental studies have found the presence of (Cu)-Ni-Mn-Si clusters in neutron irradiated reactor pressure vessel steels, prompting concerns that these clusters could lead to larger than expected increases in hardening, especially at high fluences late in life. The mechanics governing clustering for the Fe-Mn-Ni-Si system are not well-known; state-of-the-art methods use kinetic Monte Carlo (KMC) parameterized by density functional theory (DFT) and thermodynamic data to model the time evolution of clusters. However, DFT-based KMC studies have so far been limited to only pairwise interactions due to lack of DFT data. Here, we explicitly calculate the binding energy of triplet clusters of Mn, Ni, Cu, Si, and vacancies in bcc Fe using DFT to show that the presence of vacancies, Si, or Cu stabilizes cluster formation, as clusters containing exclusively Mn and/or Ni are not energetically stable in the absence of interstitials. We further identify which clusters may be reasonably approximated as a sum of pairwise interactions and which instead require an explicit treatment of the three-body interaction, showing that the three-body term can account for as much as 0.3 eV, especially for clusters containing vacancies.
Intermolecular interaction energies from fourth order many-body perturbation theory. Impact of individual electron correlation contributions
Authors: Heßelmann Andreas
Published: September 2019

The performance of Møller-Plesset perturbation theory methods for describing intermolecular interaction energies has been investigated with the focus on illuminating the impact of individual electron correlation energy contributions in fourth order. It is shown that a physically meaningful decomposition of the fourth order correlation energy can be obtained by grouping individual correlation energy terms that share the same diagrammatic loop structure. This decomposition of the fourth order singles (S), doubles (D), triples (T), and quadruples (Q) terms revealed that individual terms from each excitation class can have a huge impact on the energy that is much larger than the total fourth order correlation contribution. A partial summation of S, D, and Q terms has been derived that can reproduce the full fourth order interaction energies with a good accuracy and which does not include the computationally expensive triples energy term.
Dependence of a cooling rate on structural and vibrational properties of amorphous silicon: A neural network potential-based molecular dynamics study
Authors: Li Wenwen , Ando Yasunobu
Published: September 2019

Amorphous materials have variable structural order, which has a significant influence on their electronic, transport, and thermal properties. However, this difference in structure has rarely been investigated by atomistic modeling. In this study, a high-quality machine-learning-based interatomic potential was used to generate a series of atomic structures of amorphous silicon with different degrees of disorder by simulated cooling from the melt with different cooling rates (1011–1015 K/s). We found that the short- and intermediate-range orders are enhanced with decreasing cooling rate, and the influence of the structural order change is in excellent agreement with the experimental annealing process in terms of the structural, energetic, and vibrational properties. In addition, by comparing the excess energies, structure factors, radial distribution functions, phonon densities of states, and Raman spectra, it is possible to determine the corresponding theoretical model for experimental samples prepared with a certain method and thermal history.
Resolving the ultrafast intersystem crossing in a bimetallic platinum complex
Authors: Valentine Andrew J. S. , Radler Joseph J. , Mills Alexis , Kim Pyosang , Castellano Felix N. , Chen Lin X. , Li Xiaosong
Published: September 2019

Bimetallic platinum complexes have interesting luminescent properties and feature long-lasting vibrational coherence and ultrafast intersystem crossing (ISC) after photoexcitation. Ultrafast triplet formation is driven by very strong spin-orbit coupling in these platinum (II) systems, where relativistic theoretical approaches beyond first-order perturbation theory are desirable. Using a fully variational relativistic theoretical method recently developed by the authors, we investigate the origins of ultrafast ISC in the [Pt(ppy) (μ-tBu2pz)]2 complex (ppy = phenylpyridine, pz = pyrazolate). Spin-orbit coupling values, evaluated along a Born-Oppenheimer molecular dynamics trajectory, are used to propagate electronic populations in time. Using this technique, we estimate ultrafast ISC rates of 15–134 fs in this species for the possible ISC pathways into the three low-lying triplet states.
Optical synthetic sampling imaging: Concept and an example of microscopy
Authors: Peng Junzheng , Yao Manhong , Cai Zixin , Qiu Xue , Zhang Zibang , Li Shiping , Zhong Jingang
Published: September 2019

Digital two-dimensional spatial sampling devices have been widely used in various imaging systems, particularly in computational imaging systems. However, the undersampling of digital sampling devices is a problem that limits the resolution of the acquired images. Here, we propose synthetic sampling imaging to solve the undersampling problem. By moving the specimen from the focal plane but within the depth of field of the objective, the proposed approach allows sampling the specimen from the detection and illumination sides simultaneously. Then, it can synthesize the illumination and detection sampling to improve the sampling rate of the imaging system. An example of microscopy validated the feasibility of the proposed synthetic sampling imaging. The synthetic sampling scheme, in which the illumination and detection sides share the sampling task, provides a way of resolving the undersampling problem in digital imaging systems, especially in nonvisible light imaging systems.
Cu-Cu low temperature bonding based on lead-free solder with graphene interlayer
Authors: Yang Wenhua , Zhou Jie , Jiang Xinyuan , Ye Ximing , Xuan Xiaofeng , Wu Chunyan , Luo Linbao
Published: September 2019

In order to suppress the immoderate growth of intermetallic compounds (IMCs) at the Sn-Cu bonding interface, we transferred multilayer graphene between the Sn solder and the Cu film sample as an interlayer. Then, an external pressure of ∼350 N was applied to the two Cu film samples at 150 °C for 5 min to realize bonding using a thermo-compression bonding machine. After bonding, the sample was placed in an oven at 150 °C for an aging test. The IMC layer grew at the bonding interface gradually with the aging duration increasing for both cases. The growth rate of the IMC layer with the graphene interlayer is much lower than that without the graphene interlayer. For 72 h aging, the thickness of the IMC layer at the interface of Sn-graphene-Cu bonding reduces by about 55% relative to that of Sn-Cu bonding. The reduction rate of bonding strength with the graphene interlayer is also lower than that without the graphene interlayer. For 72 h aging, the shear strength of Sn-Cu bonding is lower than that of Sn-graphene-Cu bonding. Through comparison of data measured by the 4-point probe test, it is found that the contact resistances of Sn-graphene-Cu bonding have no obvious difference from those of Sn-Cu bonding after aging. Thus, the graphene transfer and low temperature process can suppress the interfacial reaction and the immoderate growth of IMC to retard aging, and the multilayer graphene interlayer has no significant negative influence on the electrical properties of the bonding.
Drag reduction in turbulent flow along a cylinder by circumferential oscillating Lorentz force
Authors: Zhao Ming-Xiang , Huang Wei-Xi , Xu Chun-Xiao
Published: September 2019

Direct numerical simulations are performed to study the drag reduction effect in turbulent flow along a cylinder by the circumferential oscillating Lorentz force at the Reynolds number Reτ = 272 based on the reference friction velocity and the thickness of the boundary layer. The maximum drag reduction rate obtained in the present work is 42.6%. The intensity, penetration thickness, distribution (idealized or realistic), and oscillation period of the Lorentz force are all crucial in determining the drag reduction rate. As the Lorentz force is intensified or its penetration thickness and oscillation period increase, the wall friction drag will prominently decrease as long as the circumferential flow is stable. The Stokes layer, introduced by the circumferential oscillating Lorentz force, effectively manipulated the near-wall coherent structures, leading to the decrease of the wall friction drag. However, the occurrence of the force-induced vortices in the near-wall region can also lead to significant drag increase by enhancing the radial momentum transportation due to centrifugal instability. By estimating the energy consumption rate, it is clear that the extra power to implement the Lorentz force is far more than the power saved due to drag reduction, which is the result of the low conductivity of the fluid media. Taking the coupling between the electromagnetic field and the flow field into consideration, the wall friction drag is nearly zero and the turbulence intensity in the near-wall region is very low when the induced Lorentz force is high. But the induced Lorentz drag is greatly increased and the turbulence fluctuations are enhanced in the outer region.
New multistage converter promises a new sub-nanosecond high-voltage pulse generator
Authors: Zhang Zhengzheng
Published: September 2019

Scientists have developed a new cascade high voltage pulse converter based on nonlinear transmission lines, producing extreme parameters of the output pulses.
Fluorescence microscopy sheds light on the behavior of proteins in hydrogels
Authors: Bandari Anashe
Published: September 2019

Combining common fluorescence microscopy techniques reveals new information about protein dynamics.
Eco-friendly compound Cu2SnS3 shows promise as a thermoelectric material
Authors: Mandel Savannah
Published: September 2019

Scientists explore the thermoelectric properties of Cu 2 SnS 3  by systematically varying its copper and tin content and studying its band structure and transport properties.
Dietary nitrogen utilisation and prediction of amino acid requirements in equids
Authors: Trottier Nathalie L. , Tedeschi Luis O.
Published: September 2019

The equine population represents an important sector of animal agriculture and, thus, contributes to environmental contamination. The horse industry lags behind other livestock industries in developing prediction models to estimate N and amino acid (AA) requirements aimed at precision feeding and management to optimise animal health and performance while mitigating nutrient excretion. Effective predictions of N utilisation and excretion are based on knowledge of ingredient protein quality and the determinants of N and AA requirements. Protein quality is evaluated on the basis of N and AA digestibility and AA composition. Amino acid composition of grains, pulses and oil seeds is extensive, but there is large deficit on that of forages. Several studies have reported on pre- and post-caecal N digestibility in horses, demonstrating that a large proportion of N from forages is metabolised post-caecally. Few have reported on AA digestibility. It is proposed that whole-tract (i.e. faecal) N and AA digestibility be used in evaluating feed-ingredient protein quality in equids to begin designing predictive models of N and AA requirements. Nitrogen gain and AA composition in deposited tissues and their corresponding efficiency of utilisation are the key determinants for a prediction model. We estimated that N utilisation for maintenance is 0.74. Maintenance requirements for N and AA were derived from faecal N and AA losses in horses and expressed as a function of dry-matter intake and from integument losses in swine. Relative to our factorial model, the NRC (2007) requirement for lysine and N is overestimated when based on a segmented curve and a breakpoint. When based on N equilibrium, lysine NRC (2007) requirement estimate agrees with our factorial model estimate, while N requirement is underestimated. The pool of AA profile used to express requirements of other essential AA has a large impact on requirement, as shown, in particular, for threonine. Threonine requirement based on faecal endogenous AA profile is higher than is lysine requirement for maintenance and lactation.
The future protein decade: perspectives on global pressure to agriculture
Authors: McGill Julian , Moss Amy , Swick Robert , Jackson David , Todd Martin
Published: September 2019

Most of the world’s arable area is sown to either grains or oilseeds, and it is the big movements in the profitability of these crops that determine the pressure on global cropping-area supply. This perspective incorporates publicly available data, primarily from the FAO, to demonstrate some of the shifting pressures on global agriculture. Additionally, it argues that the advent of biofuel policies created additional demand for the area to produce cereal and oil crops from 2002. However, with a slowing demand growth for ethanol biofuels, crops for human and animal consumption will once again become the main driver for crop acreage. In particular, protein crops will be favoured as higher incomes are strongly linked to a greater animal-product consumption. In addition, a shift to a more intensive animal production is further increasing the demand for protein crops. Therefore, we could ultimately see a contraction in cereal crops and much faster growth in oilseeds, albeit from a lower base, as the demand for feed becomes the main driver for global agriculture. Yet, this is occurring during a time in which protein content of the major oil crops has been declining (albeit while yields continue to increase).
The Guanidine-Promoted Direct Synthesis of Open-Chained Carbonates
Authors: Shang Yuhan , Zheng Mai , Zhang Haibo , Zhou Xiaohai
Published: September 2019

In order to reduce CO2 accumulation in the atmosphere, chemical fixation methodologies were developed and proved to be promising. In general, CO2 was turned into cyclic carbonates by cycloaddition with epoxides. However, the cyclic carbonates need to be converted into open-chained carbonates by transesterification for industrial usage, which results in wasted energy and materials. Herein, we report a process catalyzed by tetramethylguanidine (TMG) to afford linear carbonates directly. This process is greener and shows potential for industrial applications.
International postal, quarantine and safety regulations
Authors: Smith David , Ryan Matthew
Published: September 2019

There are numerous legislative regulations that impact on microbiology, microbial Biological Resource Centres (mBRCs) and culture collections, with which all microbiologists must comply. These affect access for collection, handling, distribution/shipping and utilisation of microbial resources. Areas where regulations are triggered are international post, quarantine and safety. The legislation and supporting documents are often difficult to find and understand, therefore the World Federation for Culture Collections (WFCC) has a long history in providing advice and guidance to help compliance with such legislation. A visit to the WFCC library (http://www.wfcc.info/wfcc_library/) will provide information on postal requirements shipping dangerous goods and on control measures in place for biosecurity to control access to dangerous pathogens. This paper will update such communications and provide relevant information on: Health and Safety (H&S); Quarantine regulations; and Postal Regulations and Safety. Other papers in this special issue will address elements that impact on distribution and use of microorganisms for example in packaging, legislation on the proliferation, distribution and misuse of dangerous pathogens, export licensing measures, the Convention on Biological Diversity and the Nagoya Protocol, ownership of Intellectual Property Rights (IPR) and the provision of safety information to the recipient of microorganisms. The advice is generic and users are advised to refer to their own National guidance and implementation acts to ensure they are compliant. The work was compiled from authors' efforts in their management of an mBRC and most recently contributions to the EMBRIC project (http://www.embric.eu/) in particular Deliverable 6.1 ‘Microbial pipeline from environment to active compounds' (http://www.embric.eu/deliverables).