bluuebunny/crossref_metadata_2025 huggingface dataset:
Longitudinal development of the gut microbiota in healthy and diarrheic piglets induced by age‐related dietary changes
Authors: Yang Qiaoli , Huang Xiaoyu , Wang Pengfei , Yan Zunqiang , Sun Wenyang , Zhao Shengguo , Gun Shuangbao
Published: September 2019

Diarrhea is one of the most common enteric diseases in young piglets. Diverse factors such as an unstable gut microenvironment, immature intestinal immune system, early supplementary feeding, and weaning often induce dysfunction of gut microbiota, thus leading to a continuing high incidence of diarrhea in piglets. However, few studies have characterized the gut microbiota of diarrheic piglets following changes in diet and during the development of intestinal physiology. In this study, we used 16S rRNA gene sequencing to analyze the dynamic establishment of fecal microbiota in six healthy piglets in response to age‐related changes in the diet: sow‐reared, early supplementary creep‐feeding (sow‐reared + starter diet), and weaning (solid nursery diet). We compared the gut microbiota of these six healthy piglets with those of diarrheic piglets during each of the three dietary stages (n = 10 sow‐reared, n = 10 early supplementary creep‐feeding, and n = 5 weaning). We found that weaning (solid nursery feeding) was the primary factor leading to dynamic colonization by microbiota in healthy piglets, and diarrhea primarily affected the microbial communities of piglets before weaning. Healthy piglets showed a continuous decrease in Lactobacillus and Escherichia, as well as a gradual increase in Prevotella with the transition to solid food. An altered relationship between Prevotella and Escherichia may be the main cause of diarrhea in preweaned piglets, whereas reduced numbers of Bacteroides, Ruminococcus, Bulleidia, and Treponema that are responsible for the digestion and utilization of solid feeds may be related to the onset of postweaning piglet diarrhea. The Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) functional analysis indicated that a reduction in genes involved in carbohydrate metabolism induced by intestinal dysbacteriosis in diarrheic piglets was one of the major causes of diarrhea at the three dietary stages. These findings provide insights into developing an intervention strategy for better management of diarrhea in piglets.
Optimum design of helical antennas by genetic algorithm
Authors: Lovestead Raymond L. , Safaai‐Jazi Ahmad
Published: September 2019

The genetic algorithm is employed to obtain optimal designs for helical antennas that, over the frequency range of operation, provide considerably smaller axial ratio, higher gain, and an appreciably wider overall bandwidth than the conventional axial mode helices with the same size. Also, for nearly equal bandwidth and peak directivity, the new design provides a 2 to1 reduction in size. For these helical antennas the pitch angle and radius, which are constant in conventional helices, vary continuously along the length; pitch angle increases while radius decreases. Genetic algorithm is used to determine variations of these parameters such that maximum directivity and minimum axial ratio are simultaneously achieved over the largest frequency range. Radiation properties of optimized helices, including far‐field pattern, axial ratio, and directivity, are examined numerically over a wide range of frequencies. Empirical design equations are provided. A 12‐turn prototype optimized helix is constructed and measured. Comparison of measured and simulated radiation patterns shows excellent agreement.
Simultaneous respiratory motion correction and image reconstruction in 4D‐multi pinhole small animal SPECT
Authors: Naseri Maryam , Rajabi Hossein , Wang Jing , Abbasi Mehrshad , Kalantari Faraz
Published: September 2019

Purpose

Respiratory motion in the chest region during single photon emission computed tomography (SPECT) is a major degrading factor that reduces the accuracy of image quantification. This effect is more notable when the tumor is very small, or the spatial resolution of the imaging system is less than the respiratory motion amplitude. Small animals imaging systems with sub‐millimeter spatial resolution need more attention to the respiratory motion for quantitative studies. We developed a motion‐embedded four‐dimensional (4D)‐multi pinhole SPECT (MPS) reconstruction algorithm for respiratory motion correction. This algorithm makes full use of projection statistics for reconstruction of every individual frame.

Methods

The ROBY phantom with small tumors in liver was generated in eight different phases during one respiratory cycle. The MPS projections were modeled using a fast ray tracing method simulating an MPS acquisition. Individual frames were reconstructed and used for motion estimation. The Demons non‐rigid registration algorithm was used to calculate deformation vector fields (DVFs) for simultaneous motion correction and image reconstruction. A motion‐embedded 4D‐MPS method was used to reconstruct images using all the projections and corresponding DVFs, simultaneously. The 4D‐MPS reconstructed images were compared to the low‐count single frame (LCSF) reconstructed image, the three‐dimensional (3D)‐MPS images reconstructed using individual frames, and post reconstruction registration (PRR) that aligns all individual phases to a reference frame using Demons‐derived DVFs. The tumor volume relative error (TVE), tumor contrast relative error (TCE), and dice index (DI) for 2, 3, and 4 mm liver were calculated and compared for different reconstruction methods.

Results

For the 4D‐MPS reconstruction method, TVE was reduced and DI was higher compared to PRR, 3D‐MPS, and LCSF. The extent of the improvement was higher for the small tumor size (i.e. 2 mm). For the biggest tumor in contrast 3 (i.e. 4 mm) TVE for 4D‐MPS, PRR, 3D‐MPS and, LCSF were 1.33%, 8%, 8%, and 14.67%, respectively.

Conclusions

The results suggest that motion‐embedded 4D‐MPS method is an effective and practical way for respiratory motion correction. It reconstructs high quality gated frames while using all projection data to reconstruct each frame.
The use of MM/QM calculations of 13C and 15N chemical shifts in the conformational analysis of alkyl substituted anilines
Authors: Abraham Raymond J. , Cooper Marcus Ashley
Published: September 2019

The calculation of the 13C and 15N NMR chemical shifts by a combined molecular mechanics (Pcmodel 9.1/MMFF94) and ab initio (GIAO (B3LYP/DFT, 6‐31 + G(d)) procedure is used to investigate the conformations of a variety of alkyl substituted anilines. The 13C shifts are obtained from the GIAO isotropic shielding (Ciso) with separate references for sp3 and sp2 carbons (δc = δref − Ciso). The 15N shifts are obtained similarly from the GIAO isotropic shielding (Niso) with reference to the 15N chemical shift of aniline. Comparison of the observed and calculated shifts provides information on the molecular conformations. Aniline and the 2,6‐dialkylanilines exist with a rapidly inverting symmetric pyramidal nitrogen atom. The 2‐alkylanilines have similar conformations with the NH2 group tilted away from the 2‐alkyl substituent. The N,N‐dialkylanilines show more varied conformations. N,N‐dimethylaniline has a similar structure to aniline, but N‐ethyl, N‐methylaniline, N,N‐diethylaniline, and N,N‐diisopropylaniline are conformationally mobile with two rapidly interconverting conformers. In contrast, the anilines substituted at C2 and the nitrogen atom exist as one conformer where the steric interaction between the C2 substituent and the N substituent determines the conformation. In 2‐methyl‐N‐methylaniline, the nitrogen atom is pyramidal as usual with the N‐methyl opposite to the 2‐methyl, but in 2‐methyl‐N,N‐dimethyl aniline, the NMe2 group is now almost orthogonal to the phenyl plane. This is also the case with 2‐methyl‐N,N‐diethylaniline and 2,6‐diisopropyl‐N,N‐dimethylaniline. The comparison of the observed and calculated 15N chemical shifts confirms the above findings, in particular the pyramidal conformation of aniline and the above observations with respect to the conformations of the N,N‐dialkylanilines.
Assessing pathological changes within the nucleus ambiguus of horses with recurrent laryngeal neuropathy: An extreme, length‐dependent axonopathy
Authors: Draper Alexandra C.E. , Cahalan Stephen D. , Goodwin David , Perkins Justin , Piercy Richard J.
Published: September 2019

Introduction

Equine recurrent laryngeal neuropathy (RLN) is a naturally occurring model of length‐dependent axonopathy characterized by asymmetrical degeneration of recurrent laryngeal nerve axons (RLn). Distal RLn degeneration is marked, but it is unclear whether degeneration extends to include cell bodies (consistent with a neuronopathy).

Methods

With examiners blinded to RLN severity, brainstem location, and side, we examined correlations between RLN severity (assessed using left distal RLn myelinated axon count) and histopathological features (including chromatolysis and glial responses) in the nucleus ambiguus cell bodies, and myelinated axon count of the right distal RLn of 16 horses.

Results

RLN severity was not associated with RLn cell body number (P > .05), or degeneration. A positive correlation between the left and right distal RLn myelinated axon counts was identified (R2= 0.57,P < .05).

Discussion

We confirm that RLN, a length‐dependent distal axonopathy, occurs in the absence of detectable neuronopathy.
Importance of early diagnosis in LMNA‐related muscular dystrophy for cardiac surveillance
Authors: Choi Sun Ah , Cho Anna , Kim Soo Yeon , Kim Woo Joong , Shim Young Kyu , Lee Jin Sook , Jang Se Song , Lim Byung Chan , Kim Hunmin , Hwang Hee , Choi Ji Eun , Kim Ki Joong , Kim Man Jin , Seong Moon‐Woo , Chae Jong‐Hee
Published: September 2019

Introduction

The identification of LMNA‐related muscular dystrophy is important because it poses life‐threatening cardiac complications. However, diagnosis of LMNA‐related muscular dystrophy based on clinical features is challenging.

Methods

We reviewed the clinical phenotypes of 14 children with LMNA variants, focusing on the cardiac function and genotypes.

Results

Most patients presented with motor developmental delay or gait abnormalities. Eight (57%) patients had prominent neck extensor weakness or contractures. All patients showed ankle contractures at an early stage. Regular cardiac surveillance allowed for the detection of dysrhythmias in 57% of patients at a mean age of 14 years (range, 5–26). All patients had missense variants; however, there were no clear phenotype–genotype correlations.

Discussion

Early diagnosis of LMNA‐related muscular dystrophy provides an opportunity for cardiac surveillance, potentially leading to the prevention of cardiac mortality in children.
European Federation of Neurological Societies cutoff values significantly reduce creatine kinase sensitivity for diagnosing neuromuscular disorders
Authors: Abraham Alon , Katzberg Hans D. , Lovblom Leif E. , Bril Vera
Published: September 2019

Introduction

Elevated creatine kinase (CK) level was redefined by the European Federation of Neurological Societies)EFNS(as 1.5 times the upper limit of normal. In the current study we sought to determine the sensitivity and specificity of CK testing for the diagnosis of neuromuscular disorders.

Methods

Demographics and CK levels were retrospectively extracted from an electronic database for 234 patients with neuromuscular disorders. Sensitivity, specificity, and likelihood ratios and the area under curve were determined for each diagnosis and different cutoff CK values.

Results

Using the EFNS cutoff values significantly reduced CK test sensitivity. Creatine kinase values >1000 IU/L showed a high likelihood (11.04) for myopathies and a low likelihood for polyneuropathies (0).

Discussion

European Federation of Neurological Societies cutoff values significantly reduce CK sensitivity for diagnosing neuromuscular disorders. While low CK values cannot exclude a neuromuscular disease, values >1000 IU/L are associated with a high likelihood of myopathy.
Skeletal muscle unloading results in increased mitophagy and decreased mitochondrial biogenesis regulation
Authors: Leermakers Pieter A. , Kneppers Anita E.M. , Schols Annemie M.W.J. , Kelders Marco C.J.M. , de Theije Chiel C. , Verdijk Lex B. , van Loon Luc J.C. , Langen Ramon C.J. , Gosker Harry R.
Published: September 2019

Introduction

Physical inactivity significantly contributes to loss of muscle mass and performance in bed‐bound patients. Loss of skeletal muscle mitochondrial content has been well‐established in muscle unloading models, but the underlying molecular mechanism remains unclear. We hypothesized that apparent unloading‐induced loss of muscle mitochondrial content is preceded by increased mitophagy‐ and decreased mitochondrial biogenesis‐signaling during the early stages of unloading.

Methods

We analyzed a comprehensive set of molecular markers involved in mitochondrial‐autophagy, −biogenesis, −dynamics, and ‐content, in the gastrocnemius muscle of C57BL/6J mice subjected to 0‐ and 3‐days hind limb suspension, and in biopsies from human vastus lateralis muscle obtained before and after 7 days of one‐leg immobilization.

Results

In both mice and men, short‐term skeletal muscle unloading results in molecular marker patterns indicative of increased receptor‐mediated mitophagy and decreased mitochondrial biogenesis regulation, before apparent loss of mitochondrial content.

Discussion

These results emphasize the early‐onset of skeletal muscle disuse‐induced mitochondrial remodeling.
Impact of the Liverpool Care Pathway on quality end‐of‐ care in residential care homes and home care—Nurses’ perceptions
Authors: Olsson Cecilia , Kling Elisabeth , Grundel Persson Karina , Larsson Maria
Published: September 2019

Aim

Aim was to describe how Registered Nurses (RNs) and assistant nurses (ANs) working in residential care homes and home care perceived quality end‐of‐life care after implementation of the Liverpool Care Pathway (LCP) in terms of subjective importance of care aspects and actual care given.

Design

Descriptive cross‐sectional.

Methods

Registered Nurses (N = 22; 100% response rate) and ANs (N = 120; 59% response rate) working in a Swedish municipality. Data collection with a study‐specific questionnaire (50 items) about perceived reality (PR) and subjective importance (SI). Non‐parametric statistics.

Results

Implementation of the LCP ensured systematic assessment and alleviation of patients’ symptoms and needs. The ANs, more than the RNs, perceived that the patients received the best possible nursing and medical care (p = .01). Both groups considered that communication with patients and families as well as the information exchange between the team members was facilitated. Areas for improvement were identified about psychological and existential support and patients and families’ participation in care.
A case of secondary syphilis presenting on the oral mucosa: A case report
Authors: Harada Yusei , Amekawa Shigeki , Takubo Kazuko , Otsuki Kazuma , Kawasaki Makoto , Tamura Takayuki , Fujii Nobuyuki , Kodani Isamu
Published: September 2019

Syphilis is a sexually transmitted disease caused by Treponema pallidum. We report a case of secondary syphilis originating in the oral mucosa. The patient was a 58‐year‐old man who visited our hospital at May 2009. Clinical examination revealed a mass at the right angle of the mouth with a white mass on the tip of the tongue and an indurated ulcer on the left border of the tongue. Magnetic resonance imaging revealed multiple swollen lymph nodes in the bilateral submandibular glands, as well as in the bilateral deep cervical and supraclavicular lymph nodes. Serological examination revealed elevated rapid plasma reagin (RPR) (titer, 1:32) and Fluorescent treponemal antibody absorption test (2+) values. Consequently, the mass at the right angle of the mouth, the white patch on the tip of the tongue, and the ulcer on the left border of the tongue were diagnosed as secondary syphilis. Oral amoxicillin 1500 mg/d was administered for 4 weeks. The oral lesions improved after 20 days of treatment and the RPR titer had improved to 1:2 after 5 months of treatment.
Analysis‐suitable CAD Models based on Watertight Boolean Operations
Authors: Marussig Benjamin , Urick Benjamin , Cohen Elaine , Crawford Richard H. , Hughes Thomas J. R. , Riesenfeld Richard F.
Published: September 2019

Isogeometric analysis has established a new paradigm in computational engineering that significantly improves the interoperability problem between design and analysis, but addressing the full scope of the issue requires adaptations of traditional CAD concepts as well. The recently introduced watertight Boolean operations resolve a fundamental inconsistency in the underlying representations of current CAD models. We investigate the suitability of the resulting geometries for analysis purposes; in particular, in the context of isogeometric boundary element methods. The results confirm that watertight Boolean operations yield CAD models that meet the requirements of numerical simulations.
A Numerical RANS‐Based Model of a Nanosecond Pulsed Plasma Actuator for Flow Control over an Airfoil
Authors: Aslani Roozbeh , Krieger Michael
Published: September 2019

Airfoil stall influences the performance of flight vehicles and remains a challenge for the design of modern aircraft. A Dielectric Barrier Discharge (DBD) device seems to be a promising tool to control the flow over various parts of an aircraft and to suppress separation. A phenomenological model based on dynamic similarity is developed to simulate the control effect of a Nanosecond Dielectric Barrier Discharge (NS‐DBD) actuator. A two‐dimensional numerical simulation considers the response of the flow past a NACA 0015 airfoil at 14° post stall angle of attack and a Reynolds number of 250,000 to pulsed surface heating at the leading edge. The RANS‐based numerical results have been obtained for a baseline simulation (no actuation) and an open‐loop control simulation of the airfoil. A one‐equation local correlation‐based transition model is implemented to capture laminar‐turbulent transition. The numerical results of both the baseline and the actuated case are in good agreement with experiments performed by other authors.
A Retrospective Study of the Association between Pain Intensity and Opioid Use with Length of Stay during Musculoskeletal Inpatient Rehabilitation after Primary Knee and Hip Arthroplasty
Authors: Sahota Bhupinder , Alavinia Seyed Mohammad , Kumbhare Dinesh , Sangha Harpreet , Flannery John , Furlan Andrea
Published: September 2019

Background

The relationship between pain intensity, opioid consumption, and length of stay (LOS) has received little attention in primary, lower extremity joint arthroplasty patients admitted to inpatient musculoskeletal rehabilitation.

Objective

To assess how initial pain and other clinical factors are associated with rehabilitation LOS.

Design

Retrospective chart review.

Setting

Rehabilitation hospital.

Participants

One hundred ninety nine patients admitted for inpatient rehabilitation.

Interventions

Not Applicable.

Main Outcome Measures

Pain intensities on the Numeric Rating Scale (NRS) were completed 3 times daily and total daily opioid consumption recorded in terms of morphine equivalents (MEQ). Confounding variables included patient demographics, medical comorbidity burden using the Charlson Comorbidity Index (CCI), and early functional status as measured by the motor subscale from the Functional Independence Measure (FIM).

Results

Mean day 3 NRS values of ≥5.2 and total day 3 opioid consumption of >50 MEQ were associated with a prolonged LOS by nearly 3 and 2 days, respectively. Within a multivariate linear regression, age, mean day 3 pain, comorbidity burden, and early motor functional status accounted for 36% of the variability seen in joint replacement rehabilitation LOS. With all other variables remaining constant, for every unit increase in mean day 3 pain and CCI, this amounted to an additional 5% and 4% increase to LOS, whereas each unit increase in admission motor FIM decreased estimated LOS by 3%.

Conclusion

Mean pain intensity and total opioid consumption on day 3 of inpatient rehabilitation is associated with LOS. For the rehabilitation physician, this is useful information as the earlier identification of patients with poorly controlled pain can lead to directed intervention, better patient care, and significant cost savings.
Multimodal pain assessment improves discrimination between noxious and non‐noxious stimuli in infants
Authors: van der Vaart Marianne , Duff Eugene , Raafat Nader , Rogers Richard , Hartley Caroline , Slater Rebeccah
Published: September 2019

Infants in neonatal intensive care units frequently experience clinically necessary painful procedures, which elicit a range of behavioral, physiological, and neurophysiological responses. However, the measurement of pain in this population is a challenge and no gold standard exists. The aim of this study was to investigate how noxious‐evoked changes in facial expression, reflex withdrawal, brain activity, heart rate, and oxygen saturation are related and to examine their accuracy in discriminating between noxious and non‐noxious stimuli. In 109 infants who received a clinically required heel lance and a control non‐noxious stimulus, we investigated whether combining responses across each modality, or including multiple measures from within each modality improves our ability to discriminate the noxious and non‐noxious stimuli. A random forest algorithm was used to build data‐driven models to discriminate between the noxious and non‐noxious stimuli in a training set which were then validated in a test set of independent infants. Measures within each modality were highly correlated, while different modalities showed less association. The model combining information across all modalities had good discriminative ability (accuracy of 0.81 in identifying noxious and non‐noxious stimuli), which was higher than the discriminative power of the models built from individual modalities. This demonstrates the importance of including multiple modalities in the assessment of infant pain.
Airway disease on chest computed tomography of preschool children with cystic fibrosis is associated with school‐age bronchiectasis
Authors: Bouma Nynke R. , Janssens Hettie M. , Andrinopoulou Eleni‐Rosalina , Tiddens Harm A. W. M.
Published: September 2019

Airway wall thickening and mucus plugging are important characteristics of cystic fibrosis (CF) lung disease in the first 5 years of life.The aim of this study is to investigate the association of lung disease in preschool children (age, 2‐6) with bronchiectasis and other clinical outcome measures in the school age (age >7). Deidentified computed tomography‐scans were annotated using Perth‐Rotterdam annotated grid morphometric analysis for CF. Preschool %disease (a composite score of %airway wall thickening, %mucus plugging, and %bronchiectasis) and %MUPAT (a composite score of %airway wall thickening and %mucus plugging) were used as predictors for %bronchiectasis and several other school‐age clinical outcomes. For statistical analysis, we used regression analysis, linear mixed‐effects models and two‐way mixed models. Sixty‐one patients were included. %Disease increased significantly with age (P  <  .01). Preschool %disease and %MUPAT were significantly associated with school‐age %bronchiectasis (P  <  .01 and P  <  .01, respectively). No significant association was found between preschool %disease and %MUPAT and school‐age forced expiratory volume 1 (FEV1%) predicted and quality of life (P  >  .05). Cross‐sectional, %disease in school‐age was associated with a low FEV1% predicted and low quality of life (P  =  .01 and P  =  .007, respectively). %Disease can be considered an early marker of diffuse airways disease and is a risk factor for school‐age bronchiectasis.
Predictors of time to cough resolution in children with chronic wet cough treated with antibiotics after bronchoscopy
Authors: Wong Oi Yin , Marchant Julie M. , Yerkovich Stephanie T. , Chang Anne B.
Published: September 2019

Background

Chronic wet cough is common in pediatric pulmonology practice and is clinically important. Guidelines recommend treatment with antibiotics as their effectiveness has been proven. However, factors associated with duration of cough in response to antibiotics in children with chronic wet cough have not been prospectively examined.

Objective

To determine if demographic, clinical and/or bronchoalveolar lavage (BAL) factors are associated with “time to cough resolution” in children with chronic wet cough treated with antibiotics after bronchoscopy.

Methods

Data from children with chronic wet cough treated with antibiotics after bronchoscopy were extracted from a prospective cohort study database. Cough dairies were used to determine when the cough resolved. Associations between various factors with “time to cough resolution” were examined using regression.

Results

The median age of the 133 children was 2.4 years (interquartile range, 1.4‐4.9). Duration of prior cough at bronchoscopy was significantly positively related with “time to cough resolution” (β = .010; 95% confidence interval, 0.004‐0.017; P = .002). This translated to; for each month of prior cough, it took an extra 1.02 days to achieve cough resolution while on antibiotic treatment. Gender, age, diagnosis, tobacco smoke exposure, pneumonia history, blood cellularity, and BAL cellular and microbiology profiles were not significantly associated with time to cough resolution.

Conclusion

In children with chronic wet cough, duration of cough before antibiotic treatment is a small but significant determinant of “time to cough resolution.” Research using standardized antibiotic regimes is required to provide clinical and/or biomarkers that can further identify factors associated with the response of chronic cough to antibiotic treatment.
Differentiation of isomeric cresols by silylation in combination with gas chromatography/mass spectrometry analysis
Authors: Xu Jiaxiang , Zhu Guohua , Zhang Huarong , Liu Jinsong , Jiang Kezhi
Published: September 2019

Rationale

m‐Cresol is listed as a priority controlled contaminant in many countries, but it is very difficult to accurately determine isomeric cresols due to their incomplete chromatographic separation on commercially available chromatographic columns and their nearly identical mass spectra.

Methods

Silylation of isomeric cresols was carried out by treatment with N‐methyl‐N‐(trimethylsilyl)trifluoroacetamide. The formed trimethyl(tolyloxy)silanes were analyzed by gas chromatography/mass spectrometry (GC/MS). Theoretical calculations were carried out with the Gaussian 03 program using the density functional theory (DFT) method at the B3LYP/6‐311 + G(2d,p) level.

Results

The derivatives of three isomeric cresols and six isomeric xylenols have been completely separated on an HP‐5MS capillary column within a GC run of only 10 minutes. In addition, the derivative o‐cresol can be very easily differentiated from its isomers due to its characteristic base peak ion at m/z 91 in electron ionization (EI)‐MS. DFT calculation results indicated that the formation of the abundant fragment ion at m/z 91 is attributed to a facile dissociation pathway involving the shift of a neighboring phenylmethyl hydrogen atom in EI‐MS of trimethyl(o‐tolyloxy)silane.

Conclusions

Silylation provides a promising solution for simultaneous determination of isomeric cresols and isomeric xylenols.
Quantifying the impact of recovery during chromatographic purification on the accuracy of lithium isotopic determination by multi‐collector inductively coupled plasma mass spectrometry
Authors: Gou Long‐Fei , Liu Chun‐Yao , Deng Li , Jin Zhangdong
Published: September 2019

Rationale

Lithium (Li) isotopes have increasingly been applied as tracers in Earth and planetary sciences and their effectiveness relies upon accurate and precise Li isotopic data. Nowadays, multi‐collector inductively coupled plasma mass spectrometry (MC‐ICP‐MS) combined with chromatographic purification is the most common strategy for obtaining Li isotopic ratios in natural samples, with a long‐term internal precision better than 0.3‰ in most laboratories. However, there is a large discrepancy in the Li isotopic compositions of the same reference materials determined by MC‐ICP‐MS among international laboratories (e.g. ca 3.5‰ difference for measurements of homogeneous seawater), which has been attributed to insufficient recovery of Li during chromatographic purification. Despite this recognition, the exact impact of Li recovery during purification on Li isotopic determinations by MC‐ICP‐MS has never been quantified.

Methods

We employed a normal distribution function to model Li elution curves and quantified the Li isotopic fractionation resulting from Li recovery during chromatographic purification. Furthermore, we compared the calculated and measured relative recovery (R) with the Li isotopic ratios determined by ICP‐MS to validate our theoretical calculation.

Results

The theoretical calculations showed that R should be higher than 99.8% in order to avoid observable Li isotopic fractionation during chromatographic purification at IEECAS. This idea is further supported by the better long‐term external precisions for data with R ≥ 99.8% compared with previous values of 99.5% ≤ R < 99.8%. Our results indicated that the large differences in the reported Li isotopic ratios for homogeneous seawater among international laboratories are probably attributable to Li isotopic fractionation occurring during ion exchange chromatography.

Conclusions

Our theoretical calculation via R is the first quantitative and convenient approach for monitoring Li isotopic fractionation during sample purification, ensuring that R ≥ 99.8% can avoid observable Li isotopic fractionation during purification, which will improve the accuracy of Li isotopic measurements by MC‐ICP‐MS and the comparability among laboratories.
Identification of significant protein markers by mass spectrometry after co‐treatment of cells with different drugs: An in vitro survey platform
Authors: Wu Ying‐Jung , Huang Ching‐Hui , Hsieh Tusty‐Jiuan , Tseng Wei‐Lung , Lu Chi‐Yu
Published: September 2019

Rationale

Understanding drug–drug interactions and predicting the side effects induced by polypharmacy are difficult because there are few suitable platforms that can predict drug–drug interactions and possible side effects. Hence, developing a platform to identify significant protein markers of drug–drug interactions and their associated side effects is necessary to avoid adverse effects.

Methods

Human liver cells were treated with ethosuximide in combination with cimetidine, ketotifen, metformin, metronidazole, or phenytoin. After sample preparation and extraction, mitochondrial proteins from liver cells were isolated and digested with trypsin. Then, peptide solutions were detected using a nano ultra‐performance liquid chromatographic system combined with tandem mass spectrometry. The Ingenuity Pathway Analysis tool was used to simulate drug–drug interactions and identify protein markers associated with drug‐induced adverse effects.

Results

Several protein markers were identified by the proposed method after liver cells were co‐treated with ethosuximide and other drugs. Several of these protein markers have previously been reported in the literature, indicating that the proposed platform is workable.

Conclusions

Using the proposed in vitro platform, significant protein markers of drug–drug interactions could be identified by mass spectrometry. This workflow can then help predict indicators of drug–drug interactions and associated adverse effects for increased safety in clinical prescriptions.
Reasoning about genetic mechanisms: Affordances and constraints for learning
Authors: Haskel‐Ittah Michal , Duncan Ravit Golan , Vázquez‐Ben Lucia , Yarden Anat
Published: September 2019

Mechanisms are central in scientific explanations. However, developing mechanistic explanations is difficult for students especially in domains in which mechanisms involve abstract components and functions, such as genetics. One of the core components of genetic mechanisms are proteins and their functions. Students struggle to reason about the role of proteins while learning genetics and show limited ability to provide mechanistic explanations of genetic phenomena. In genetics education there are currently two competing theoretical frameworks regarding what domain‐specific knowledge about proteins is important for reasoning about genetic mechanisms. One framework assumes knowledge about specific protein functions in the body, a tool kit of functions; the other framework assumes more abstracted knowledge about protein interactions that are common to all protein functions. These frameworks implicate different instructional frameworks: One offers to provide concrete examples of protein functions while the other offers a more general description of protein activity. Our aim in this study was to ascertain the ways in which students' reasoning about proteins' role in genetic phenomena (both familiar and novel) relates to the two theoretical frameworks. Toward this end we engaged 7th grade students in learning about proteins functions in the mechanisms underlying genetic traits using an online simulation environment that embodied key aspects of both frameworks. We analyzed students' responses to the final test questions in which they were asked to generatively reason about the underlying mechanisms of two novel genetic traits. Our findings suggest that students use proteins in their explanations mainly when they can explain the protein function and that knowledge about a few specific functions is insufficient to support conceptualization of new functions. Moreover, knowledge of general protein activities common to most functions is also insufficient. We suggest a new combined approach to supporting students' understanding of proteins' role in genetic mechanisms.
Migration, ethnicity and psychoses: evidence, models and future directions
Authors: Morgan Craig , Knowles Gemma , Hutchinson Gerard
Published: September 2019

There is a large body of research reporting high rates of psychotic disorders among many migrant and minority ethnic groups, particularly in Northern Europe. In the context of increasing migration and consequent cultural diversity in many places worldwide, these findings are a major social and public health concern. In this paper, we take stock of the current state of the art, reviewing evidence on variations in rates of psychoses and putative explanations, including relevant theories and models. We discuss in particular: a) the wide variation in reported rates of psychotic disorders by ethnic group, and b) the evidence implicating social risks to explain this variation, at ecological and individual levels. We go on to set out our proposed socio‐developmental model, that posits greater exposure to systemic social risks over the life course, particularly those involving threat, hostility and violence, to explain high rates of psychoses in some migrant and minority ethnic groups. Based on this analysis, the challenge of addressing this social and public health issue needs to be met at multiple levels, including social policy, community initiatives, and mental health service reform.
The efficacy of app‐supported smartphone interventions for mental health problems: a meta‐analysis of randomized controlled trials
Authors: Linardon Jake , Cuijpers Pim , Carlbring Per , Messer Mariel , Fuller‐Tyszkiewicz Matthew
Published: September 2019

Although impressive progress has been made toward developing empirically‐supported psychological treatments, the reality remains that a significant proportion of people with mental health problems do not receive these treatments. Finding ways to reduce this treatment gap is crucial. Since app‐supported smartphone interventions are touted as a possible solution, access to up‐to‐date guidance around the evidence base and clinical utility of these interventions is needed. We conducted a meta‐analysis of 66 randomized controlled trials of app‐supported smartphone interventions for mental health problems. Smartphone interventions significantly outperformed control conditions in improving depressive (g=0.28, n=54) and generalized anxiety (g=0.30, n=39) symptoms, stress levels (g=0.35, n=27), quality of life (g=0.35, n=43), general psychiatric distress (g=0.40, n=12), social anxiety symptoms (g=0.58, n=6), and positive affect (g=0.44, n=6), with most effects being robust even after adjusting for various possible biasing factors (type of control condition, risk of bias rating). Smartphone interventions conferred no significant benefit over control conditions on panic symptoms (g=–0.05, n=3), post‐traumatic stress symptoms (g=0.18, n=4), and negative affect (g=–0.08, n=5). Studies that delivered a cognitive behavior therapy (CBT)‐based app and offered professional guidance and reminders to engage produced larger effects on multiple outcomes. Smartphone interventions did not differ significantly from active interventions (face‐to‐face, computerized treatment), although the number of studies was low (n≤13). The efficacy of app‐supported smartphone interventions for common mental health problems was thus confirmed. Although mental health apps are not intended to replace professional clinical services, the present findings highlight the potential of apps to serve as a cost‐effective, easily accessible, and low intensity intervention for those who cannot receive standard psychological treatment.
Electroweak baryogenesis with vector-like leptons and scalar singlets
Authors: Bell Nicole F. , Dolan Matthew J. , Friedrich Leon S. , Ramsey-Musolf Michael J. , Volkas Raymond R.
Published: September 2019

Abstract

We investigate the viability of electroweak baryogenesis in a model with a first order electroweak phase transition induced by the addition of two gauge singlet scalars. A vector-like lepton doublet is introduced in order to provide CP violating interactions with the singlets and Standard Model leptons, and the asymmetry generation dynamics are examined using the vacuum expectation value insertion approximation. We find that such a model is readily capable of generating sufficient baryon asymmetry while satisfying electron electric dipole moment and collider phenomenology constraints.
Kinetic Energy Represented in Terms of Moments of Vorticity and Applications
Authors: Cieślak Tomasz , Oleszkiewicz Krzysztof , Preisner Marcin , Szumańska Marta
Published: September 2019

We study 2d vortex sheets with unbounded support. First we show a version of the Biot–Savart law related to a class of objects including such vortex sheets. Next, we give a formula associating the kinetic energy of a very general class of flows with certain moments of their vorticities. It allows us to identify a class of vortex sheets of unbounded support being only $$\sigma $$σ-finite measures (in particular including measures $$\omega $$ω such that $$\omega (\mathbb {R}^2)=\infty $$ω(R2)=∞), but with locally finite kinetic energy. One of such examples are celebrated Kaden approximations. We study them in details. In particular our estimates allow us to show that the kinetic energy of Kaden approximations in the neighbourhood of an origin is dissipated, actually we show that the energy is pushed out of any ball centered in the origin of the Kaden spiral. The latter result can be interpreted as an artificial viscosity in the center of a spiral.
Daytime Versus Night‐Time Emergency Abdominal Operations: Perspective from a Low–Middle‐Income Country
Authors: Ndegbu C. U. , Olasehinde O. , Sharma A. , Arowolo O. A. , Adisa A. O. , Alatise O. I. , Adesunkanmi A. R. K. , Lawal O. O.
Published: September 2019

Background

Emergency abdominal operations carry significant risk of mortality and morbidity. The time of the day when such operations are performed has been suggested as a predictor of outcome. A retrospective comparison of outcomes of daytime and night‐time emergency abdominal operations was conducted.

Methods

Clinical data of patients who had abdominal operations over a five‐year period were obtained. Operations were classified as ‘daytime’ (group A) if performed between 8.00 am and 7.59 pm or ‘night time’ if performed between 8.00 pm and 7.59 am (group B). Post‐operative outcomes were compared.

Results

A total of 267 emergency abdominal operations were analysed: 161 (60.3%) were performed in the daytime while 106 (39.7%) were performed at night. The case mix in both groups was similar with appendectomies, bowel resections and closure of bowel perforations accounting for the majority. Baseline characteristics and intra‐operative parameters were similar except that ‘daytime’ operations had more consultant participation (p = 0.01). Mortality rates (13.7% in group A and 12.3% in group B, p = 0.2), re‐operation rates (9.3% in group A and 10.4% in group B, p = 0.7) and duration of hospital stay (group A—11.1 days, group B—12.4 days p = 0.4) were similar. ASA status, re‐operation and admission into the intensive care unit were identified as predictors of mortality.

Conclusion

Timing of emergency abdominal operations did not influence outcomes. In resource‐limited settings where access to the operating room is competitive, delaying operations till daytime may be counterproductive. Patients’ clinical condition still remains the most important parameter guiding time of operation.
Acquisition of Surgical Skills by Final‐Year Medical Students in State‐Owned Medical Schools of Cameroon: Are We Doing Any Good?
Authors: Chichom‐Mefire Alain , Keith Njel Gaby , Abongwa Acho , Nsagha Dickson Shey , Ngowe‐Ngowe Marcelin
Published: September 2019

Introduction

World Health Organization recommends that basic surgical care be administered at the district level. In the absence of qualified surgeons, general practitioners are sometimes proposed to bridge the gap. Medical curricula in low‐ and middle‐income countries must be designed accordingly. The aim of this study was to assess the achievements of training of undergraduate medical students in Cameroon towards meeting this objective.

Methods

A descriptive cross‐sectional study was carried out in the four state‐owned medical schools in Cameroon. All students who had completed all clinical rotations were assessed with a self‐administered questionnaire for their exposure and self‐perceived comfort in conducting some selected basic surgical skills and procedures.

Results

A total of 304 (87.6%) students returned filled questionnaires. Their self‐perceived comfort in surgical skills ranged from 25% (manual node tying) to 86% (surgical scrubbing). Adequate exposure to selected surgical procedures was 87% for repair of perineal tear complicating vaginal delivery, above 80% for caesarean section and incision and drainage of abscess, 73% for cast immobilization of extremity fracture and just above 50% for hernia repair and appendectomy. It was as low as 3% for bowel resection and anastomosis. The choice to perform extra‐curricular activity for skills improvement was significantly associated with adequate exposure (p < 0.05).

Conclusion

Overall, the mastery of practical surgical skills and basic surgical interventions by final‐year medical students in Cameroon is insufficient. There is need to reinforce the training and assessment by creating the conditions for an appropriate exposure of medical students during surgical rotations.
Historical anthropogenic heavy metal input to the south-eastern North Sea
Authors: Boxberg Florian , Asendorf Sanja , Bartholomä Alexander , Schnetger Bernhard , de Lange Willem P. , Hebbeln Dierk
Published: September 2019

The Helgoland Mud Area (HMA) in the German Bight, covering an area of approximately 500 km2, is one of a few depocentres for finer sediments in the North Sea. Radiocarbon and 210Pb analyses revealed continuous sedimentation over the last several centuries. Zinc (Zn) and lead (Pb) contents in the sediments show a distinct increase towards the youngest most sediments with the thickness of the heavy metal enriched sediments ranging from 15 to 103 cm. Stratigraphic data indicate that the onset of heavy metal enrichment is diachronous progressing north-westward over the depocentre, paralleled by a decrease in the thickness of the enriched layer. Beginning already during medieval times, the enhanced input of Zn and Pb seemingly is related to silver and zinc mining in the Harz Mountains and the Erzgebirge, well-known mining areas since the Bronze Age. Both regions are directly connected to the HMA by the Elbe and Weser rivers. Zn and Pb enrichment began in the south-eastern HMA and progressed subsequently with an average of 10 m per year north-westward, most likely triggered by variations in river discharge and by the hydrodynamic setting. Quantitative assessments of the Zn and Pb content in the sediments suggest that since the onset of enhanced Zn and Pb deposition, the anthropic Zn and Pb input in the HMA amounts to ~ 12,000 t and ~ 4000 t, respectively.
Whole spine MRI is not required in investigating uncomplicated paediatric lumbosacral lipoma. A retrospective single-institution review
Authors: Layard Horsfall Hugo , Chari Aswin , Huttunen Terhi , Simcock Clare , D’Arco Felice , Thompson Dominic
Published: September 2019

Purpose

Lumbosacral lipoma (LSL) is a severe occult spinal dysraphism, frequently associated with neurological, urological and orthopaedic complications. Whole spine imaging is typically performed to identify concomitant, but spatially separate, congenital anomalies. Our hypothesis: the incidence of additional, clinically significant abnormalities of the neuraxis is low; thus, imaging should be optimised at the lumbosacral region. We aim to assess the prevalence and relevance of LSL-associated lesions.

Method

A single-centre, retrospective, radiological review using a prospectively maintained operative database. Inclusion criteria: children (< 16 years) with confirmed diagnosis of LSL and received whole spine MRI. Fatty filum, syndromic cases and cutaneous stigmata above lesion level were excluded. Data was extracted from radiological imaging, reports and clinical correspondence.

Results

One hundred twelve patients (40:72, M:F) aged 0.5 years (0.2–2.7) (median ± IQR) with LSL had whole spine MRI between 2001 and 2017. Classification of LSL: transitional 48 (43%); dorsal 30 (27%); caudal 28 (25%) and chaotic 6 (5%). Additional anomalies included syringohydromyelia 44 (39%), subcutaneous tract 19 (17%), abnormal vertebral segmentation 18 (16%), dermoid cyst 1 and 1 Chiari I deformity. There were no Chiari II malformations. No child required surgery for an associated lesion. Binary logistic regression revealed no factors associated with predicting secondary lesions.

Conclusions

In congenital LSL, additional anomalies of the neuraxis are typically loco-regional rather than pan-CNS and additional lesions are rarely clinically significant. The loco-regional distribution of anomalies suggests that only lumbosacral spinal imaging is required in the initial evaluation of LSL. Such a policy would lessen the anaesthetic/sedation time for children and reduce imaging cost per patient. MRI protocols could be refined to optimise imaging quality at the region of interest.