bluuebunny/crossref_metadata_2025 huggingface dataset:
TMI (Too much information)! Effects of given information on organic chemistry students’ approaches to solving mechanism tasks
Authors: DeCocq Victoria , Bhattacharyya Gautam
Published: October 2018

We report our qualitative study of twenty-four students enrolled in the second-semester of a second-year undergraduate (sophomore-level) organic chemistry course, Organic Two. We asked the research participants to propose the product and electron-pushing mechanism of elementary mechanistic steps in the absence and presence of the corresponding overall transformation. We also asked the students about their preferences of representational systems when working on tasks common to Organic Two to ascertain the extent to which an external representation, rather than a task, might evoke a problem-solving strategy. In addition to familiarity to instructional materials, the main reason for which the students preferred line-angle formulas for nearly all of the task types is that the representational system allowed them most readily extract relevant, or otherwise useful, information without distracting them. However, line-angle formulas did not seem to cue students to the three-dimensional attributes of molecules; only dash-and-wedge structures and Newman and chair conformers did so. For the electron-pushing tasks, the research participants’ reasoning processes included at least some chemical characteristics of the species involved in the transformation when they were not given the product of reaction. When provided with the overall transformation, however, the students changed their focus to getting to the product. Consequently, they replaced correct answers with incorrect ones when given the reaction products. These results raise the possibility that traditional mechanism tasks may mask students’ mechanistic reasoning ability.
Fluorescence enhancement of a ligand-activated fluorescent protein induced by collective noncovalent interactions
Authors: Lee Euihyun , Shim Sang-Hee , Cho Minhaeng
Published: October 2018

The fluorescence of fluorescent proteins with noncovalently encapsulated chromophore is enhanced by complex interactions between chromophore, protein and bound water.
Hierarchically porous MOF/polymer composites via interfacial nanoassembly and emulsion polymerization
Authors: Jin Peng , Tan Wenlong , Huo Jia , Liu Tingting , Liang Yu , Wang Shuangyin , Bradshaw Darren
Published: October 2018

In this work, we develop a general strategy for the preparation of robust hierarchically porous and readily processable MOF composites through an interfacial nanoassembly/emulsion polymerization method.
Precise control of the microstructural, optical, and electrical properties of ultrathin Ga2O3 film through nanomixing with few atom-thick SiO2 interlayer via plasma enhanced atomic layer deposition
Authors: Ma Hong-Ping , Lu Hong-Liang , Wang Tao , Yang Jian-Guo , Li Xing , Chen Jin-Xin , Tao Jia-Jia , Zhu Jing-Tao , Guo Qixin , Zhang David Wei
Published: October 2018

Ultrathin Ga2O3 films nanomixed with few atom-thick SiO2 interlayer were deposited on silicon and quartz substrates through plasma-enhanced atomic layer deposition.
Enhancing negative thermal quenching effect via low-valence doping in two-dimensional confined core–shell upconversion nanocrystals
Authors: Lei Lei , Xia Jienan , Cheng Yao , Wang Yuansheng , Bai Gongxun , Xia Han , Xu Shiqing
Published: October 2018

Doping low-valence ions in core–shell NC is applied to improve negative thermal quenching effect. With the increase in temperature from 293 to 413 K, the UC emission intensity of 20Yb/2Er : NaGdF4 (12 nm) increases by 2.2 times, whereas that of NaGdF4@20Ca/20Yb/2Er: NaGdF4 (11 nm) increases by 10.9 times.
Ultraviolet electroluminescence from a n-ZnO film/p-GaN heterojunction under both forward and reverse bias
Authors: Ai Qiu , Liu Kewei , Ma Hongyu , Yang Jialin , Chen Xing , Li Binghui , Shen Dezhen
Published: October 2018

ZnO film was fabricated on p-GaN film using the molecular beam epitaxy technique to form heterojunction light emitting diodes (LEDs).
Two uneven sisters
Authors: Vollmer B. , Pappalardo C. , Soida M. , Lançon A.
Published: October 2018

Since the Virgo cluster is the closest galaxy cluster in the northern hemisphere, galaxy interactions can be observed in it at kiloparsec resolution. The spiral galaxy NGC 4388 underwent a ram-pressure stripping event ∼200 Myr ago caused by its highly eccentric orbit within the Virgo cluster. This galaxy fulfills all diagnostic criteria for having undergone active ram-pressure stripping in the recent past: it has a strongly truncated HI and Hα disk, an asymmetric ridge of polarized radio continuum emission, extended extraplanar gas toward the opposite side of the ridge of polarized radio continuum emission, and has undergone a recent (a few hundred million years ago) quenching of its star formation activity in the outer, gas-free galactic disk. We made dynamical simulations of the ram-pressure stripping event to investigate the influence of galactic structure on the observed properties of NGC 4388. The combination of a deep optical spectrum of the outer gas-free region of the galactic disk together with deep HI, Hα, far-ultraviolet, and polarized radio continuum data allows us to constrain numerical simulations to derive the temporal ram-pressure profile, the three-dimensional velocity vector of the galaxy, and the time since peak ram pressure with a high level of confidence. From the simulations, an angle between the ram-pressure wind and the galactic disk of 30° is derived. The galaxy underwent peak ram pressure ∼240 Myr ago. The observed asymmetries in the disk of NGC 4388 are not caused by the present action of ram pressure, but by the resettling of gas that has been pushed out of the galactic disk during the ram-pressure stripping event. For the detailed reproduction of multi-wavelength observations of a spiral galaxy that undergoes or underwent a ram-pressure stripping event, galactic structure, such as spiral arms for example, must be taken into account.
First ten years of active metamaterial structures with “negative” elements
Authors: Hrabar Silvio
Published: October 2018

Almost ten years have passed since the first experimental attempts of enhancing functionality of radiofrequency metamaterials by embedding active circuits that mimic behavior of hypothetical negative capacitors, negative inductors and negative resistors. While negative capacitors and negative inductors can compensate for dispersive behavior of ordinary passive metamaterials and provide wide operational bandwidth, negative resistors can compensate for inherent losses. Here, the evolution of aforementioned research field, together with the most important theoretical and experimental results is reviewed. In addition, some very recent efforts that go beyond idealistic impedance negation and make use of inherent non-ideality, instability, and non-linearity of realistic devices, are highlighted. Finally, a very fundamental, but still unsolved issue of common theoretical framework that connects causality, stability, and non-linearity of networks with negative elements is stressed.
Numerical Simulation Analysis of Cavitation Performance of Tandem Propeller
Authors: Du Xiaoxu , Zhang Zhengdong
Published: October 2018

The steady non cavitation hydrodynamic characteristics of CLB4-55-1 tandem propeller and the steady cavitation flows of NACA66 hydrofoil are numerically studied firstly based on the RANS equations of homogeneous multiphase using CFD theory, combined with the SST k-ω turbulent model and Z-G-B cavitation model. Numerical simulation results are in good agreement with the experimental results, which indicates that the numerical method is reliable and accurate. Then, the cavitation performance of the tandem propeller are numerical simulated and analyzed. The results show that the computational model can predict the cavitation performance of tandem propeller accurately. The cavitation performance of tandem propeller is nearly the same as single propeller, however, the cavitation phenomenon of back propeller is greater than the head propeller at certain advance coefficient and cavitation number. The cavitation phenomenon will disappear with the increase of the advance coefficient or the cavitation number.
Image Caption Description of Traffic Scene Based on Deep Learning
Authors: Qu Shiru , Xi Yuling , Ding Songtao
Published: October 2018

It is a hard issue to describe the complex traffic scene accurately in computer vision. The traffic scene is changeable, which causes image captioning easily interfered by light changes and object occlusion. To solve this problem, we propose an image caption generation model based on attention mechanism. Combining convolutional neural network (CNN) and recurrent neural network (RNN) to generate an end-to-end description for traffic images. To generate a semantic description with distinct degree of discrimination, the attention mechanism is applied to language model. Using Flickr8K、Flickr30K and MS COCO benchmark datasets to validate the effectiveness of our method. The accuracy is promoted maximally by 8.6%, 12.4%, 19.3% and 21.5% in different evaluation metrics. Experiments show that our algorithm has good robustness in four different complex traffic scenarios, such as light change, abnormal weather environment, road marked target and various kinds of transportation tools.
Research on VSC-LVDC with DC Energy Storage to Improve the Stability of Microgrid Connected to Grid Operation
Authors: Shen Ming , Zhang Xiaobin
Published: October 2018

In order to improve stability of the microgrid operation connected to distribute network, the power flow fluctuations are smoothed. In this paper, a kind of flexible interconnection interface was studied in this paper, based on voltage source converter low voltage direct current(VSC-LVDC) containing energy storage. According to the mathematical model of VSC-LVDC and battery, a dual vector decoupling three-loop control strategy consisted of stages charging is proposed, and the battery charging and discharging switch control is offered, for charging and discharging of the energy storage, the bidirectional power transmission and suppressing power fluctuations. A simulation model is built that microgrid connected to distribute network using the flexible interconnection interface, and the conditions of power fluctuation, battery charging and discharging switch and the short-circuit fault at the microgrid side AC bus are simulated. The simulation results show that the control strategy effectively suppresses the power fluctuations of point of common coupling(PCC), guarantee the stability of the power flow.
Juvenile ossifying fibroma: case report and literature review. Management and differential diagnosis
Authors: Lemoine Sarah , Cassagnau Elisabeth , Bertin Hélios , Poisson Maria , Corre Pierre , Guiol Julien
Published: October 2018

Introduction: Juvenile ossifying fibroma (JOF) is a rare neoplasm characterized by the replacement of the normal bone matrix with osteo-fibrous tissue. It has the tendency to be locally aggressive despite its benign character and to have a strong tendency for recurrence. Observation: In this case report, the patient is a young man, aged 16, with rapidly advancing maxillary swelling. We describe the diagnostic procedure, the surgical procedure and the differential diagnosis to be eliminated. Discussion: The clinical presentation of JOF, and its rapid growth, can cause fear of other pathologies such as osteosarcoma. The radiological characteristics should reassure the practitioner and a histological examination confirmed the diagnosis. Conclusion: JOF is a benign tumor. It should be operated on at an early stage because of its rapid growth. In its clinical and histological presentation, its trabecular form may mimic an osteosarcoma.
Uses of tongue flaps in oroantral communication
Authors: Moumine Mohammed , Khalfi Lahcen , Choumi Faical
Published: October 2018

Introduction: The tongue flap is a surgical option to stop oroantral communication (OAC). Observation: An OAC secondary to a palatal cystic adenoid carcinoma was treated with a tongue flap. The intervention consisted of creating a pedicle flap to close the gap, which was then used to close the communication 3 weeks after the first procedure. Discussion: The tongue flap allows for the closure of the relatively large OAC, it has the advantage of being reliable and easy to perform; however, its main disadvantage is the need for two separate surgical interventions. Between the two procedures, the patient’s diet must be exclusively mixed.
Isolated lip involvement in psoriasis: an uncommon aspect of a common dermatologic condition
Authors: Bouslama Ghada , Hasni Wafa , Massoud Nour Saida Ben , Youssef Souha Ben , Boughzela Abdellatif
Published: October 2018

Introduction: Psoriasis is a chronic inflammatory skin disease that typically affects the extremities, trunk, scalp, and nails. Psoriatic cheilitis as an exclusive presentation is very rare and to our knowledge, only 6 cases have been reported to date. The absence of cutaneous lesions causes diagnostic difficulties that can result in misdiagnosis and inadequate treatment. Observation: We reported the case of a 21-year-old woman with a seven years history of scaly plaques of the vermillion of the lips as the only disease manifestation. Her cheilitis was associated with significant psychiatric morbidity. Oral biopsy showed a psoriasiform pattern. Local applications of betamethasone was proposed. Discussion: Although lip psoriasis is extremely rare, it can be the sole presentation of psoriasis even in the absence of accompanying skin lesions, other oral manifestations or a family history of psoriasis. Conclusion: Lip psoriasis should be considered in the differential diagnosis of chronic or recurrent treatment-resistant labial lesions.
Linked
color imaging improves detection of minimal change esophagitis in non-erosive
reflux esophagitis patients
Authors: Deng Pei , Min Min , Dong Tenghui , Bi Yiliang , Tang Airong , Liu Yan
Published: October 2018

Background and study aims Non-erosive reflux disease (NERD) includes
minimal change esophagitis (MCE) and no endoscopic abnormalities. However, for
most endoscopists, it is difficult to detect MCE with conventional white-light
endoscopy (WLE). Linked color imaging (LCI) technology is the most recently
developed image-enhancing technology and improves detection and differentiation
of subtle mucosal changes using a color contrast method. This study assessed the
efficacy of WLE combined with LCI for diagnosing MCE compared with WLE.

Patients and methods Between February and May 2017, 44 NERD patients and
40 healthy subjects were enrolled in our study. First, the distal esophagus was
examined using WLE followed by LCI. Second, three experienced endoscopists
observed all the patients’ white-light (WL) images and corresponding images of
WL and LCI and then recorded presence or absence of minimal change esophagitis
(MCE +/–). The proportion of minimal change between the two groups was then
compared. Third, five blinded endoscopists with different levels of endoscopic
experience assessed whether MCE was present. Intraobserver reproducibility and
interobserver agreement were described using the kappa value.

Results The proportion of MCE in the NERD group (70.8 %, 35/48) was higher
than that in the control group (22.5 %, 9/40, P < 0.001) when
diagnosed by the three experienced endoscopists. Detection rates for MCE using
WLE combined with LCI were higher than those using WLE (43/88, 48.9 % vs. 29/88,
33.0 %, P < 0.001). With WLE combined with LCI, intraobserver
reproducibility signiﬁcantly improved, indicating that the combined approach can
improve interobserver agreement compared with using WLE alone.

Conclusions Endoscopic diagnosis of MCE using WLE combined with LCI images
is effective. Intraobserver reproducibility and interobserver agreement in MCE
can be improved when LCI is applied with conventional imaging (Clinical trial
registration number: NCT03068572).
Tele-EEG: Aktuelle Anwendungen, Hindernisse und technische Lösungen
Authors: Rosenow Felix , Audebert Heinrich , Hamer Hajo , Hinrichs Hermann , Keßler-Uberti Stephanie , Kluge Tilmann , Noachtar Soheyl , Remi Jan , Sotoodeh Ali , Strzelczyk Adam , Weber Joachim , Zöllner Johann
Published: October 2018

Ziel der telemedizinischen Versorgung von Menschen mit Epilepsie ist es, eine spezialisierte Diagnostik und Therapie räumlich unabhängig zur Verfügung zu stellen. Dies spielt in Deutschland insbesondere in ländlichen, teils unterversorgten Regionen eine Rolle. In dieser Übersichtsarbeit werden aktuelle tele-epileptologische Projekte vorgestellt. Die individuellen Rahmenbedingungen und Anforderungen, die jeweiligen Hindernisse und Lösungsansätze der Projekte werden diskutiert. Zudem werden die speziellen Anforderungen des pädiatrischen tele-EEG beleuchtet. Die zur Auswertung des tele-EEGs notwendigen technischen Rahmenbedingungen und Befundungsrichtlinien werden dargestellt. Bereits abgeschlossene tele-epileptologische Projekte zeigten positive Ergebnisse auf die Qualität der Patientenversorgung.
Cap-assisted colonoscopy: a meta-analysis of high-quality randomized controlled trials
Authors: Nutalapati Venkat , Kanakadandi Vijay , Desai Madhav , Olyaee Mojtaba , Rastogi Amit
Published: October 2018

Background and study aims Standard colonoscopy (SC) is the preferred modality for screening for colon cancer; however, it carries a significant polyp/adenoma miss rate. Cap-assisted colonoscopy (CC) has been shown to improve polyp/adenoma detection rate, decrease cecal intubation time and increase cecal intubation rate when compared to standard colonoscopy (SC). However, data on adenoma detection rate (ADR) are conflicting. The aim of this meta-analysis was to compare the performance of CC with SC for ADR among high-quality randomized controlled trials.

Patients and methods We performed an extensive literature search using MEDLINE, EMBASE, Scopus, Cochrane and Web of Science databases and abstracts published at national meetings. Only comparative studies between CC and SC were included if they reported ADR, adenoma per person (APP), cecal intubation rate, and cecal intubation time. The exclusion criterion for comparing ADR was studies with Jadad score ≤ 2. The odds ratio (OR) was calculated using Mantel-Haenszel method. I2
test was used to measure heterogeneity among studies.

Results Analysis of high-quality studies (Jadad score ≥ 3, total of 7 studies) showed that use of cap improved the ADR with the results being statistically significant (OR 1.18, 95 % CI 1.03 – 1.33) and detection of 0.16 (0.02 – 0.30) additional APP. The cecal intubation rate in the CC group was 96.3 % compared to 94.5 % with SC (total of 17 studies). Use of cap improved cecal intubation (OR 1.61, 95 % CI 1.33 – 1.95) when compared to SC (P value < 0.001). Use of cap decreased cecal intubation time by an average of 0.88 minutes (95 % CI 0.37 – 1.39) or 53 seconds.

Conclusions Meta-analysis of high-quality studies showed that CC improved the ADR compared to SC.
Safety and rate of delayed adverse events with lumen-apposing metal stents (LAMS) for pancreatic fluid collections: a multicenter study
Authors: Yang Dennis , Perbtani Yaseen B. , Mramba Lazarus K , Kerdsirichairat Tossapol , Prabhu Anoop , Manvar Amar , Ho Sammy , Pannu Davindebir , Keswani Rajesh N. , Strand Daniel S. , Wang Andrew Y. , Quintero Eduardo , Buscaglia Jonathan M. , Muniraj Thiruvengadam , Aslanian Harry R. , Draganov Peter V. , Siddiqui Ali S.
Published: October 2018

Background and study aims Endoscopic drainage with dedicated lumen-apposing metal stents (LAMS) is routinely performed for symptomatic pancreatic fluid collections (PFCs), walled-off necrosis (WON) and pseudocyst (PP). There has been increasing concern regarding delayed adverse events associated with the indwelling LAMS. 

Patients and methods Multicenter retrospective analysis of consecutive patients who underwent endoscopic ultrasound (EUS)-guided LAMS placement for PFC from January 2010 to May 2017. Main outcomes included: (1) resolution of the PFC, (2) rate of delayed adverse events at follow-up, and (3) predictors of treatment failure and delayed adverse events on logistic regression.

Results A total of 122 patients (mean age 50.9 years, 68 % male) underwent LAMS insertion for 64 WON (98.4 %) and 58 PP (98.3 %). PFC mean size was 10.6 cm. PFC resolution was significantly lower for WON (62.3 %) vs. PP (96.5 %) (P < 0.001) on imaging at a median of 4 weeks. Stent occlusion was identified in 18 (29.5 %) and 10 (17.5 %) patients with WON and PP, respectively (P = 0.13). There were no cases of delayed bleeding or buried stent on follow-up endoscopy. Use of electrocautery-enhanced LAMS was the only factor associated with treatment failure of WON (OR = 13.2; 95 % ci: 3.33 – 51.82, P = 0.02) on logistic regression. There were no patient, operator, or procedure-related factors predictive of stent occlusion.

Conclusions EUS-guided LAMS for PFC is associated with a low incidence of delayed adverse events. While nearly all PPs resolve at 4 weeks permitting LAMS removal shortly thereafter, many WON persist, with use of electrocautery-enhanced LAMS being the sole predictor of treatment failure.
A Natural Phenolic Compound Quercetin Showed the Usefulness by Targeting Inflammatory, Oxidative Stress Markers and Augment 5-HT Levels in One of the Animal Models of Depression in Mice
Authors: Khan Khadeeja , Najmi Abul Kalam , Akhtar Mohd
Published: October 2018

Aim In the present study quercetin was studied for its role in inflammation, oxidative stress markers and 5-HT levels in unpredictable chronic mild stress (UCMS) animal model of depression.

Materials and Methods The mice were randomized into different groups trained for UCMS protocol followed by different drug treatments. Treatments were started after 2 weeks from the start of UCMS protocol and continued up to 6 weeks. The behavioral tests such as modified forced swimming (MFST), tail suspension (TST) and open field tests were performed on week 6, at least 24 h after the last drug treatment. Behavioral tests were preceded following animal sacrifice for biochemical estimations.

Results A significant decrease in swimming, climbing times and increase in immobility time in MFST and TST was observed in UCMS group. Administration of quercetin (25 mg/kg per orally (p.o) reversed these times in MFST and TST. A decrease in no. of field crossing, time spent in centre and no. of rearing were observed in UCMS group. Quercetin reduced these observations in open field test. There was a decrease in superoxide dismutase (SOD), glutathione (GSH), catalase and 5 HT levels in the brain tissue. Quercetin treatment significantly augmented SOD, GSH, catalase and 5 HT levels. Glutamate, TNF-α and IL-6 levels were increased in UCMS group while quercetin decreased these cytokines.

Conclusion Quercetin resulted antidepressant-like effect by its antioxidant, anti-inflammatory activities, reduced excitotoxicity and augmented 5 HT levels. This pointed out the usefulness of this phenolic compound as adjuvent drug along with other antidepressant drugs.
Review of Clinical Pharmacokinetics of Avibactam, A Newly Approved non-β lactam β-lactamase Inhibitor Drug, In Combination Use With Ceftazidime
Authors: Giri Poonam , Patel Harilal , Srinivas Nuggehally
Published: October 2018

Avibactam, a potent non-β lactam β-lactamase inhibitor, was recently approved in the USA for combination use with ceftazidime, a cephalosporin antibiotic drug. The addition of avibactam potentiates the antimicrobial drug ceftazidime, which otherwise would have been susceptible to β-lactamases produced by variety of Gram negative pathogens. The focus of this review was to provide clinical pharmacokinetic data of avibactam to cover absorption, distribution, metabolism, and excretion aspects including any potential for avibactam to show drug-drug interactions in the clinic. Based on the review of the data, the pharmacokinetics of avibactam was generally stationary in the studied dosing regimen. The elimination half-life (approximately 1.4- 3.2 h) and volume of distribution at steady state (15.4-26.3 L) were found similar across the studies and therefore, provided the complementary pharmacokinetic attributes for combination use with ceftazidime. Renal excretion was the major pathway for the clearance of avibactam. In summary, any degree of renal dysfunction is expected to alter the pharmacokinetics of avibactam – this consideration should be factored in dosage adjustments while dosing in patients with renal impairment. Concomitant drugs that may influence renal mechanism of elimination of avibactam should be avoided and/or monitored for any impact on the pharmacokinetics of avibactam.
Effect of Canagliflozin on Heart Function Involving Ketone Bodies in Patients with Type 2 Diabetes
Authors: Kutoh Eiji , Hayashi Jyunka
Published: October 2018

This report describes the effect of administration (n=3) or withdrawal (n=2) of canagliflozin, a sodium-glucose co-transporters 2 (SGLT-2) inhibitor, on cardiac function in relation to ketone bodies. Three cases received and two cases discontinued canagliflozin. Changes of heart function with ultrasonography (EF: ejection fraction and %FS: functional shortening) and cardiometabolic parameters including ketone bodies (acetoacetate/beta-hydroxybutylate) were compared at 3 months. 69, 68 and 60 years old male patients A, B and C, respectively with moderately decreased heart function received canagliflozin 100 mg/day. EF, %FS and acetoacetate/beta-hydroxybutylate levels increased. 60 and 59 years old female patients D and E with normal and borderline heart function, respectively discontinued canagliflozin 50 mg/day. EF, %FS and acetoacetate/beta-hydroxybutylate levels decreased. Taken together, these results suggest that concomitant changes between ketone bodies and heart function were observed with or without canagliflzoin. This drug might have effects on cardiac function through modulating ketone bodies.
Efficacy of Anterior Bite Plane in Class II Deep Bite Case - A Case Report
Authors: Dixit Shweta , Gupta Garima , Sharma Pooja , Gupta Sameer
Published: October 2018

Aims and Objectives: Deep bite is one of the common malocclusion which has a varied of etiologies; this case report includes correction of deep bite with help of anterior bite plane. Materials and Methods: One post pubertal patient of age 15 years with proclined maxillary incisors with class II skeletal and class II molar treated with fixed orthodontic appliance with anterior bite plane. Results: It resulted in favorable skeletal and dentoalveolar changes. Midlines were coinciding, molars were in class I relationship and smile was improved. Conclusion: Using anterior bite plane corrected class II deep bite in patient, corrected lip trap and proclined maxillary incisors.
Prospective Study of Endogenous Hormones and Incidence of Venous Thromboembolism: The Atherosclerosis Risk in Communities Study
Authors: Roetker Nicholas , MacLehose Richard , Hoogeveen Ron , Ballantyne Christie , Basu Saonli , Cushman Mary , Folsom Aaron
Published: October 2018

Exogenous hormone treatments in women (oral contraceptives and hormone replacement therapy [HRT]) are established risk factors for venous thromboembolism (VTE), but less is known about associations between plasma levels of endogenous hormones and VTE risk. We examined the association of baseline dehydroepiandrosterone sulphate (DHEAS), testosterone and sex hormone-binding globulin (SHBG) with risk of future VTE in men and post-menopausal women in the Atherosclerosis Risk in Communities Study. Testosterone, DHEAS and SHBG were measured in plasma samples collected in 1996 to 1998. Cox proportional hazards models were used to estimate hazard ratios for incident VTE adjusting for age, race/ethnicity, body mass index, height, smoking, estimated glomerular filtration rate and C-reactive protein. All analyses were stratified by sex and by current HRT use in women. Among 3,051 non-HRT-using women, 1,414 HRT-using women and 3,925 men at risk at baseline, 184, 62 and 206 experienced incident VTE after a median follow-up of 17.6 years. Plasma hormones were not associated with incidence of VTE among men and non-HRT-using women, although lower plasma DHEAS, when modelled using quartiles or restricted cubic splines, was associated with higher risk of VTE among HRT-using women. This study does not support the existence of an important association between plasma concentrations of endogenous testosterone, DHEAS or SHBG with risk of VTE in middle-aged to older men or post-menopausal women not using HRT.
Photoionization of the iodine 3d, 4s, and 4p orbitals in methyl iodide
Authors: Forbes Ruaridh , De Fanis Alberto , Bomme Cédric , Rolles Daniel , Pratt Stephen T. , Powis Ivan , Besley Nicholas A. , Simon Marc , Nandi Saikat , Milosavljević Aleksandar R. , Nicolas Christophe , Bozek John D. , Underwood Jonathan G. , Holland David M. P.
Published: October 2018

Ionization of the I 3d, 4s, and 4p orbitals in methyl iodide (CH3I) has been studied by using synchrotron radiation to measure the total ion yield and by recording photoelectron spectra with linearly polarized radiation in two polarization orientations. The complete photoelectron spectrum of CH3I has been recorded at several photon energies, and bands due to the C 1s, I 3d, 4s, 4p, and 4d atomic-like orbitals, as well as the molecular orbitals, have been observed and assigned. In the vicinity of the I 3d5/2 and 3d3/2 ionization thresholds at 626.8 and 638.3 eV, respectively, the ion yield displays weak structure in the pre-edge region due to transitions into valence or Rydberg states, and, at higher energies, a shoulder and a broad maximum attributed to the I 3d5/2 → εf and the I 3d3/2 → εf shape resonances, respectively. The absorption spectrum calculated using time-dependent density functional theory, within the Tamm-Dancoff approximation, has allowed assignments to be proposed for the valence and Rydberg states. The Stieltjes imaging technique has been used to simulate the absorption spectrum above the ionization threshold and indicates that transitions into the f(l = 3) continuum channel dominate. This conclusion has been corroborated by a Continuum Multiple Scattering–Xα (CMS–Xα) calculation. The asymmetric broadening of the photoelectron bands associated with the I 3d orbital, due to post collision interaction, is taken into account in our experimental analysis. Experimentally derived photoelectron anisotropy parameters for the I 3d orbital are in good agreement with the theoretical predictions obtained with the CMS–Xα approach. The I 3d shake-up/shake-off photoelectron spectrum has been recorded, and assignments have been proposed for several of the satellites. The M4N45N45 and M5N45N45 Auger electron yields have been measured, and that for the M5N45N45 decay exhibits a maximum due to interchannel coupling between the 3d5/2 and 3d3/2 continua. The photoelectron band associated with the I 4p orbital has an unusual appearance. Based upon previous theoretical work for the analogous Xe 4p orbital, it appears that the initial I 4p−1 hole state decays rapidly through Coster-Kronig and super-Coster-Kronig transitions. This leads to a redistribution of the spectral intensity associated with the I 4p orbital and results in a photoelectron spectrum containing a single structured band together with an extended continuum. Another continuum is observed on the high binding energy side of the peak due to the 4s orbital, and we assign this to super-Coster-Kronig transitions into the 4p-14d−1 continuum.
The single-line-of-sight, time-resolved x-ray imager diagnostic on OMEGA
Authors: Theobald W. , Sorce C. , Bedzyk M. , Ivancic S. T. , Marshall F. J. , Stoeckl C. , Shah R. C. , Lawrie M. , Regan S. P. , Sangster T. C. , Campbell E. M. , Hilsabeck T. J. , Englehorn K. , Kilkenny J. D. , Morris D. , Chung T. M. , Hares J. D. , Dymoke-Bradshaw A. K. L. , Bell P. , Celeste J. , Carpenter A. C. , Dayton M. , Bradley D. K. , Jackson M. C. , Pickworth L. , Nagel S. R. , Rochau G. , Porter J. , Sanchez M. , Claus L. , Robertson G. , Looker Q.
Published: October 2018

The single-line-of-sight, time-resolved x-ray imager (SLOS-TRXI) on OMEGA is one of a new generation of fast-gated x-ray cameras comprising an electron pulse-dilation imager and a nanosecond-gated, burst-mode, hybrid complementary metal-oxide semiconductor sensor. SLOS-TRXI images the core of imploded cryogenic deuterium–tritium shells in inertial confinement fusion experiments in the ∼4- to 9-keV photon energy range with a pinhole imager onto a photocathode. The diagnostic is mounted on a fixed port almost perpendicular to a 16-channel, framing-camera–based, time-resolved Kirkpatrick–Baez microscope, providing a second time-gated line of sight for hot-spot imaging on OMEGA. SLOS-TRXI achieves ∼40-ps temporal resolution and better than 10-μm spatial resolution. Shots with neutron yields of up to 1 × 1014 were taken without observed neutron-induced background signal. The implosion images from SLOS-TRXI show the evolution of the stagnating core.
Luminescence study on crystalline phase of Y2Si2O7 from mesoporous silica and Y2O3: Ln3+ at 900 °C
Authors: Prasad Amresh I. , Singh L. Robindro , Joshi Rashmi , Ningthoujam R. S.
Published: October 2018

Mesoporous silica nanoparticles (mSiO2) have been used in many applications including drug delivery, catalysis, sensing. In drug delivery, tracing of mSiO2 needs incorporation of organic dyes or radio nuclei, etc. However, organic dyes are unstable under various mediums or in longer duration. To overcome this, one of ways is use of lanthanide ions (Ln3+) such as Eu3+, Tb3+ or Dy3+, which show luminescence in visible as well as near infrared (NIR) regions. In this work, nanocomposites of mSiO2 and Y2O3:Ln3+ have been prepared. These are characterized by several techniques. mSiO2 is stable up to 500 °C and microstructure of mesoporous collapses at 900 °C. Interestingly, mSiO2 reacts with Y2O3 to form Y2Si2O7 phase at 900 °C. On the other hand, such phase was not formed from Y2O3 and amorphous SiO2 at same temperature. This finding of the formation of highly crystalline Y2Si2O7 at lower temperature 900 °C is the first report to the best of authors’ knowledge. Their luminescence studies are performed by single or multi doping of Ln3+ ions. Their energy transfer processes are discussed. The crystallinity of Y2O3 or Y2Si2O7 is improved after co-doping of Ce3+ to Ln3+. Such nanocomposites are highly dispersible in distilled water, methanol and PBS (Phosphate Buffered Saline).
Hydration of CH3HgOH and CH3HgCl compared to HgCl2, HgClOH, and Hg(OH)2: A DFT microsolvation cluster approach
Authors: Amaro-Estrada Jorge I. , Hernández-Cobos Jorge , Saint-Martin Humberto , Maron Laurent , Ramírez-Solís Alejandro
Published: October 2018

We address the aqueous microsolvation of the CH3HgCl and CH3HgOH molecules using a stepwise hydration scheme including up to 33 water molecules and compare our results with the previously studied HgCl2, HgClOH, and Hg(OH)2 complexes. Optimized geometries and Gibbs free energies were obtained at the B3PW91/aug-RECP(Hg)-6-31G(d,p) level. At least 33 water molecules were required to build the first solvation shell around both methylmercury compounds. Optimized geometries were found having favorable interactions of water molecules with Hg, Cl, and the OH moiety. Born-Oppenheimer molecular dynamics simulations were performed on the largest CH3HgX(X = Cl, OH)–(H2O)33 clusters at the same level of theory. Born-Oppenheimer molecular dynamics simulations at T = 300 K (ca. 0.62 kcal/mol) revealed the presence of configurations with hydrogen-bonded networks that include the OH moiety in CH3HgOH and exclude both the Hg and Cl in CH3HgCl, favoring a clathrate-type structure around the methyl moiety. The comparison to the microsolvated HgClOH, Hg(OH)2, and HgCl2 molecules showed that, in all cases, the water molecules easily move away from Cl, thus supporting the idea that HgCl2 behaves as a non-polar solute. The theoretical (LIII edge) X-ray absorption near edge structure spectra are obtained and found in good agreement with experimental data, especially for the CH3HgCl species.
Design of tangential x-ray crystal spectrometer for Aditya-U tokamak
Authors: Shah K. , Chowdhuri M. B. , Shukla G. , Manchanda R. , Mayya K. B. K. , Jadeja K. A. , Pablant N. A. , Ghosh J.
Published: October 2018

A tangential soft x-ray crystal spectrometer has been designed to measure the x-ray spectrum of He-like argon for the Aditya-U tokamak plasma. The system enables to measure electron temperature using the intensity ratio of the resonance line to the satellite line. For this purpose, an x-ray spectral line at 3.9494 Å from He-like argon, Ar16+, is considered. The spectrometer consists of a cylindrically bent silicon (111) crystal and a CCD detector to measure the resonance spectral line and its satellite lines in the wavelength region of 3.94–4.0 Å, viewing the plasma tangentially at an angle of 26° with respect to the toroidal direction in the magnetic axis. Considering Aditya-U tokamak plasma parameters and its geometrical constraints, plasma to crystal and crystal to detector distances have been kept at 1.47 m and 0.5 m, respectively, to detect a sufficient signal. The engineering design has been optimized after adequately addressing the issues related to port geometry and machine accessibility. Details on the design of the crystal spectrometer are presented in this paper.
Calibration of the field strength of broadband terahertz radiation in air coherent detection technique
Authors: Du Hai-Wei , Tang Fu , Zhang Dong-Yu , Sheng Wang , Mao Jing-Yi
Published: October 2018

In the air coherent detection of the terahertz (THz) technique, a high voltage signal with a square waveform offers a modulated biased field over the air sensor. In this technique, a temporal THz waveform can be obtained routinely. However, its field strength has to be calibrated separately by other techniques. In this paper, we propose a method to calibrate the field strength of the THz pulse by means of applying a positive square wave instead of an alternating square wave as the modulated biased field. In this method, the ratio of the THz signal to the background signal is used for the calibration of the field strength of the THz pulse. Using this method, both the waveform and the electric field strength of the THz pulse can be easily obtained.
Mott insulators: A large class of materials for Leaky Integrate and Fire (LIF) artificial neuron
Authors: Adda Coline , Corraze Benoit , Stoliar Pablo , Diener Pascale , Tranchant Julien , Filatre-Furcate Agathe , Fourmigué Marc , Lorcy Dominique , Besland Marie-Paule , Janod Etienne , Cario Laurent
Published: October 2018

A major challenge in the field of neurocomputing is to mimic the brain's behavior by implementing artificial synapses and neurons directly in hardware. Toward that purpose, many researchers are exploring the potential of new materials and new physical phenomena. Recently, a new concept of the Leaky Integrate and Fire (LIF) artificial neuron was proposed based on the electric Mott transition in the inorganic Mott insulator GaTa4Se8. In this work, we report on the LIF behavior in simple two-terminal devices in three chemically very different compounds, the oxide (V0.89Cr0.11)2O3, the sulfide GaMo4S8, and the molecular system [Au(iPr-thiazdt)2] (C12H14AuN2S8), but sharing a common feature, their Mott insulator ground state. In all these devices, the application of an electric field induces a volatile resistive switching and a remarkable LIF behavior under a train of pulses. It suggests that the Mott LIF neuron is a general concept that can be extended to the large class of Mott insulators.
Structural transition of vortices to nonlinear regimes in a dusty plasma
Authors: Laishram Modhuchandra , Zhu Ping
Published: October 2018

The structural transition of a steady state dust flow from linear to nonlinear regimes is analyzed using a two-dimensional hydrodynamic model for the dust fluid confined in an axisymmetric toroidal system along with an unbounded streaming plasma. Numerical solutions of the employed hydrodynamical model not only confirms the analytical structure of the driven dust vortex flow in the linear limit as reported in the previous analysis but also shows how the dust vortices are strongly affected by the nonlinear convective transport of the flow at the higher Reynolds number (Re) regime. Effects of various system parameters including external driving field and the Reynolds number are investigated within the linear to nonlinear transition regime 0.001 ≤ Re < 50. In agreement with relevant experimental observations, the steady flow structure which is symmetric around the center in the linear regime begins to turn asymmetric in the nonlinear regime. The structure of the steady dust flow is found to be influenced mainly by the dissipation scales due to kinematic viscosity, ion drag, and neutral collision in the nonlinear regime, whereas, in the linear regime, it is mainly controlled by the external driving field and the confining boundaries.
Independent amplitude approximations in coupled cluster valence bond theory: Incorporation of 3-electron-pair correlation and application to spin frustration in the low-lying excited states of a ferredoxin-type tetrametallic iron-sulfur cluster
Authors: Small David W. , Head-Gordon Martin
Published: October 2018

Coupled cluster valence bond (CCVB) is a simple electronic structure method based on a perfect pairing (PP) reference with 2-pair recouplings for strong electron correlation problems. CCVB is spin-pure, size-consistent, and can exactly (in its active space) separate any molecule into atoms for which unrestricted Hartree-Fock (UHF) at dissociation is the sum of the ground state UHF energies of the atoms. However CCVB is far from a complete description of strong correlations. Its first failure to exactly describe spin-recouplings arises at the level of 3 electron pairs, such as the recoupling of 3 triplet oxygen atoms in the dissociation of singlet ozone. Such situations are often associated with spin frustration. To address this limitation, an extension of CCVB, termed CCVB+i3, is reported here that includes an independent (i) amplitude approximation to the 3-pair recouplings. CCVB+i3 thereby has the same basic computational requirements as those of CCVB, which has previously been shown to be an efficient method. CCVB+i3 correctly separates molecules that CCVB cannot. As a by-product, an independent 2-pair amplitude approximation to CCVB, called PP+i2, is also defined. Remarkably, PP+i2 can also correctly separate systems that CCVB cannot. CCVB+i3 is validated on the symmetric dissociation of D3h ozone. CCVB+i3 is then used to explore the role of 3-pair recouplings in an [Fe4S4(SCH3)4]2− cluster that has been used to model the iron-sulfur core of [Fe4S4] ferredoxins. Using localized PP orbitals, such recouplings are demonstrated to be large in some low-lying singlet excited states of the cluster. Significant 3 pair recoupling amplitudes include the usual triangular motif associated with spin frustration and other geometric arrangements of the 3 entangled pairs across the 4 iron centers.
Effect of driving pulse properties on the performance of sub-terawatt laser wakefield acceleration
Authors: Hsieh C.-Y. , Lin M.-W. , Chen S.-H.
Published: October 2018

By introducing a sub-terawatt (TW) laser pulse into a high-density gas target, the self-focusing effect and the self-modulation instability can greatly enhance the laser peak power to a level capable of driving the laser wakefield acceleration (LWFA) of electrons. A particle-in-cell model has been developed to study the scheme in which 1030-nm pulses produced from a diode-pumped laser system are introduced into a gas cell with a flat-top density profile, allowing the LWFA to be operated at high frequencies. Because 1030-nm lasers are typically produced with a long duration >200 fs, a spectral broadening technique can be applied to reduce the pulse duration, from which a greater ponderomotive force is acquired to drive LWFA. To understand the dependence of LWFA performance on the driving pulse duration, selected durations, ranging from 200 fs to 10 fs, are assigned for 0.5-TW, 1030-nm pulses in a series of simulations. Results show that a duration around 50 fs can provide the optimal LWFA results, as a compromise between the weak ponderomotive force available from a long pulse >100 fs and the depletion effect which can rapidly diminish a short pulse <25 fs in a dense plasma. When a low laser peak power of 0.25-TW is available, the pulse depletion can be significant at a high target density and render LWFA ineffective. Using a laser pulse with a longer wavelength >2 μm represents a viable route to realize the LWFA with a low laser peak power; in this way, an appropriately selected target density which allows the laser peak power PL ∼ 1.25Pcr of self-focusing critical power is favourable for realizing an efficient LWFA process.
Readable racetrack memory via ferromagnetically coupled chiral domain walls
Authors: Shen Maokang , Zhang Yue , You Long , Yang Xiaofei
Published: October 2018

Current-induced motion of domain walls (CIMDWs) with the interfacial Dzyaloshinskii-Moriya interaction (DMI) in heavy metal (HM)/ferromagnetic (FM) metal multilayers has attracted attention owing to their potential applications in novel magnetic memories. In recent years, the CIMDW at ultrahigh speed has been observed in a synthetic antiferromagnetic (SAF) multilayer with a high storage density because of the weak stray field. However, due to the zero net magnetization, the reading of information from the SAF multilayer is still challenging. In this work, we propose a readable racetrack memory consisting of a synthetic ferromagnetic multilayer composed of two FM layers with an interlayer FM coupling. One FM layer had an isotropic DMI, while the other had an anisotropic DMI. This difference of DMIs resulted in the opposite tilting directions of the DW planes in the two layers. This tilting was inhibited by a strong interlayer FM coupling, resulting in an increase in the DW velocity and the reduction of the minimum allowed spacing between two adjacent DWs. In addition, the FM coupling enhanced the stray field, and the stored information could be read conveniently using a conventional reading head. Therefore, our proposal paves the way for the fabrication of a racetrack memory with high reading speed, large storage density, and good readability.
Even-handed subsystem selection in projection-based embedding
Authors: Welborn Matthew , Manby Frederick R. , Miller Thomas F.
Published: October 2018

Projection-based embedding offers a simple framework for embedding correlated wavefunction methods in density functional theory. Partitioning between the correlated wavefunction and density functional subsystems is performed in the space of localized molecular orbitals. However, during a large geometry change—such as a chemical reaction—the nature of these localized molecular orbitals, as well as their partitioning into the two subsystems, can change dramatically. This can lead to unphysical cusps and even discontinuities in the potential energy surface. In this work, we present an even-handed framework for localized orbital partitioning that ensures consistent subsystems across a set of molecular geometries. We illustrate this problem and the even-handed solution with a simple example of an SN2 reaction. Applications to a nitrogen umbrella flip in a cobalt-based CO2 reduction catalyst and to the binding of CO to Cu clusters are presented. In both cases, we find that even-handed partitioning enables chemically accurate embedding with modestly sized embedded regions for systems in which previous partitioning strategies are problematic.