bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linkage to care, mobility and retention of HIV‐positive postpartum women in antiretroviral therapy services in South Africa
Authors: Phillips Tamsin K , Clouse Kate , Zerbe Allison , Orrell Catherine , Abrams Elaine J , Myer Landon 
Published: July 2018

AbstractIntroductionLinkage to care and mobility postpartum present challenges to long‐term retention after initiating antiretroviral therapy (ART) in pregnancy, but there are few insights from sub‐Saharan Africa. We aimed to describe postpartum linkage to care, mobility, retention and viral suppression after ART initiation in pregnancy.MethodsUsing routine electronic data we assessed HIV‐specific health contacts and clinic movements among women initiating ART in an integrated antenatal care (ANC) and ART clinic in Cape Town, South Africa. The local care model includes mandatory transfer to general ART clinics postpartum. We investigated linkage to care after leaving the integrated clinic and mobility to new clinics until 30 months on ART. We used Poisson regression to explore predictors of linkage, retention (accessing care at least once at both 12 [6 to <18] and 24 [18 to <30] months on ART), and viral suppression (HIV viral load [VL] ≤50 and ≤1000 copies/mL after 12 months on ART).ResultsAmong 617 women, 23% never linked to care; 71% and 65% were retained at 12 and 24 months on ART respectively, with 59% retained in care at both times. Those who linked (n = 485) accessed HIV care at 98 different clinics and 21% attended ≥2 clinics. Women >25 years, married/cohabiting or presenting early for ANC were more likely to link. Younger and unemployed women were more likely to attend ≥2 clinics (adjusted risk ratio [aRR] 1.10 95% confidence interval [CI] 1.02 to 1.18 and aRR 1.06 95% CI 0.99 to 1.12 respectively). Age >25 years (aRR 1.17 95% CI 1.02 to 1.33) and planned pregnancy (aRR 1.20 95% CI 1.09 to 1.33) were associated with being retained. Among 338 retained women with VL available, attending ≥2 clinics reduced the likelihood of viral suppression when defined as ≤50 copies/mL (aRR 0.81 95% CI 0.69 to 0.95). Distance moved was not associated with VL.ConclusionsThese data show that a substantial proportion of women do not link to postpartum ART care in this setting and, among those that do, long‐term retention remains a challenge. Women move to a variety of clinics and young women appear particularly vulnerable to attrition. Interventions promoting linkage and continued retention for women initiating ART during pregnancy warrant urgent consideration.
The impact of population dynamics on the population HIV care cascade: results from the ANRS 12249 Treatment as Prevention trial in rural KwaZulu‐Natal (South Africa)
Authors: Larmarange Joseph , Diallo Mamadou Hassimiou , McGrath Nuala , Iwuji Collins , Plazy Mélanie , Thiébaut Rodolphe , Tanser Frank , Bärnighausen Till , Pillay Deenan , Dabis François , Orne‐Gliemann Joanna ,   the ANRS 12249 TasP Study Group
Published: July 2018

AbstractIntroductionThe universal test and treat strategy (UTT) was developed to maximize the proportion of all HIV‐positive individuals on antiretroviral treatment (ART) and virally suppressed, assuming that it will lead to a reduction in HIV incidence at the population level. The evolution over time of the cross‐sectional HIV care cascade is determined by individual longitudinal trajectories through the HIV care continuum and underlying population dynamics. The purpose of this paper is to quantify the contribution of each component of population change (in‐ and out‐migration, HIV seroconversion, ageing into the cohort and definitive exit such as death) on the HIV care cascade in the context of the ANRS 12249 Treatment as Prevention (TasP) cluster‐randomized trial, investigating UTT in rural KwaZulu‐Natal, South Africa, between 2012 and 2016.MethodsHIV test results and information on clinic visits, ART prescriptions, viral load and CD4 count, migration and deaths were used to calculate residency status, HIV status and HIV care status for each individual on a daily basis. Position within the HIV care continuum was considered as a score ranging from 0 (undiagnosed) to 4 (virally suppressed). We compared the cascade score of each individual joining or leaving the population of resident adults living with HIV with the average score of their cluster at the time of entry or exit. Then, we computed the contribution of each entry or exit on the average cascade score and their annualized total contribution, by component of change.ResultsWhile the average cascade score increased over time in all clusters, that increase was constrained by population dynamics. Permanent exits and ageing into the people living with HIV cohort had a marginal effect. Both in‐migrants and out‐migrants were less likely to be retained at each step of the HIV care continuum. However, their overall impact on the cross‐sectional cascade was limited as the effect of in‐ and out‐migration balanced each other. The contribution of HIV seroconversions was negative in all clusters.ConclusionsIn a context of high HIV incidence, the continuous flow of newly infected individuals slows down the efforts to increase ART coverage and population viral suppression, ultimately attenuating any population‐level impact on HIV incidence.Clinical Trial NumberNCT01509508 (clinicalTrials.gov)/DOH‐27‐0512‐3974 (South African National Clinical Trials Register).
Households, fluidity, and HIV service delivery in Zambia and South Africa – an exploratory analysis of longitudinal qualitative data from the HPTN 071 (PopART) trial
Authors: Hoddinott Graeme , Myburgh Hanlie , de Villiers Laing , Ndubani Rhoda , Mantantana Jabulile , Thomas Angelique , Mbewe Madalitso , Ayles Helen , Bock Peter , Seeley Janet , Shanaube Kwame , Hargreaves James , Bond Virginia , Reynolds Lindsey ,   the HPTN 071 (PopART) Study Team
Published: July 2018

AbstractIntroductionPopulation distributions, family and household compositions, and people's sense of belonging and social stability in southern Africa have been shaped by tumultuous, continuing large‐scale historical disruptions. As a result, many people experience high levels of geographic and social fluidity, which intersect with individual and population‐level migration patterns. We describe the complexities of household fluidity and HIV service access in South Africa and Zambia to explore implications for health systems and service delivery in contexts of high household fluidity.MethodsHPTN 071 (PopART) is a three‐arm cluster randomized controlled trial implemented in 21 peri‐urban study communities in Zambia and South Africa between 2013 and 2018. A qualitative cohort nested in the trial included 148 purposively sampled households. Data collection was informed by ethnographic and participatory research principles. The analysis process was reflexive and findings are descriptive narrative summaries of emergent ideas.ResultsHouseholds in southern Africa are extremely fluid, with people having a tenuous sense of security in their social networks. This fluidity intersects with high individual and population mobility. To characterize fluidity, we describe thematic patterns of household membership and residence. We also identify reasons people give for moving around and shifting social ties, including economic survival, fostering interpersonal relationships, participating in cultural, traditional, religious, or familial gatherings, being institutionalized, and maintaining patterns of substance use. High fluidity disrupted HIV service access for some participants. Despite these challenges, many participants were able to regularly access HIV testing services and participants living with HIV were especially resourceful in maintaining continuity of antiretroviral therapy (ART). We identify three key features of health service interactions that facilitated care continuity: disclosure to family members, understanding attitudes among health services staff including flexibility to accommodate clients’ transient pressures, and participants’ agency in ART‐related decisions.ConclusionsChoices made to manage one's experiential sense of household fluidity are intentional responses to livelihood and social support constraints. To enhance retention in care for people living with HIV, policy makers and service providers should focus on creating responsive, flexible health service delivery systems designed to accommodate many shifts in client circumstances.
Modulating effects of on‐line low frequency electromagnetic fields on hippocampal long‐term potentiation in young male Sprague‐Dawley rat
Authors: Dong Lei , Zheng Yu , Li Ze‐Yan , Li Gang , Lin Ling 
Published: July 2018

AbstractThe low frequency electromagnetic fields (LF‐EMFs) are attracting more attention and studied deeply because of their effects on human health and biology. Recent reports indicate that exposure of rats to LF‐EMFs induces persistent changes in neuronal activity. The studies used the following standard methods: the rats or rat brain slices were first stimulated in an external electromagnetic exposure system, and then moved to a patch clamp perfusion chamber to record electrophysiological characteristics (off‐line magnetic exposure). However, this approach is susceptible to many disturbances, such as the effects of brain slice movements. In this paper, we describe a novel patch‐clamp setup which is modified to allow accurate on‐line LF‐EMFs stimulation. We performed the computational simulations of the stimulation coils to describe the uniformity of the distribution of the on‐line magnetic field. The 0.5, 1, 2 mT magnetic field of 15 Hz, 50 Hz, and 100 Hz was produced and applied to slices to study the effect of LF‐EMFs on synaptic plasticity. We demonstrated that the slope of field excitatory postsynaptic potentials (fEPSPs) decreased significantly under the priming on‐line uninterrupted or pulsed sinusoidal LF‐EMFs stimulation. In the present study, we investigated whether LF‐EMFs can induce long‐term potentiation (LTP) in male Sprague‐Dawley rat hippocampal slices in vitro. Interestingly, these results highlight the role of 100 Hz pulsed sinusoidal LF‐EMFs only as a modulator, rather than an LTP inducer.
Surface molecularly imprinted polymers prepared by two‐step precipitation polymerization for the selective extraction of oleanolic acid from grape pomace extract
Authors: Lu Chunxia , Tang Zonggui , Liu Changbin , Ma Xiaomei 
Published: July 2018

AbstractSurface molecularly imprinted polymers were successfully prepared by a novel two‐step precipitation polymerization method. The first‐step allowed the formation of 4‐vinylpyridine divinylbenzene and trimethylolpropane trimethacrylate copolymeric microspheres. In the second‐step precipitation polymerization, microspheres were modified with a molecularly imprinting layer of oleanolic acid as template, methacrylic acid as functional monomer, and divinylbenzene/ethylene glycol dimethacrylate as cross‐linker. The obtained polymers had an average diameter of 4.43 μm and a polydispersity index of 1.011; adsorption equilibrium was achieved within 40 min, with adsorption capacity reaching 27.4 mg/g. Subsequently, the polymers were successfully applied as the adsorbents of molecularly imprinted solid‐phase extraction to separate and purify the oleanolic acid from grape pomace. The content of oleanolic acid in the grape pomace extract was enhanced from 13.4 to 93.2% after using the molecularly imprinted solid‐phase extraction process. This work provides an efficient way for effective oleanolic acid separation and enrichment from complex matrices, which is especially valuable in industrial production.
The Value of Needle‐Guidance Technology in Ultrasound‐Guided Percutaneous Procedures Performed by Radiology Residents: A Comparison of Freehand, In‐Plane, Fixed‐Angle, and Electromagnetic Needle Tracking Techniques
Authors: England Joseph R. , Fischbeck Tucker , Tchelepi Hisham 
Published: July 2018

ObjectivesRadiology residents typically learn ultrasound‐guided procedures by performing supervised procedures on patients who may experience longer procedure times and higher complication rates. The purpose of this study was to determine if existing technologies, such as in‐plane, fixed‐angle guidance (IPFA) and electromagnetic needle tracking (ENT), can improve resident procedure time and accuracy.MethodsRadiology residents (18 total) were randomized to 1 of 3 ultrasound‐guidance technique groups—freehand, IPFA, or ENT—and instructed to place a needle into 4 liver lesions in a humanoid phantom, each increasing in difficulty. For each lesion, residents were timed from skin puncture to needle placement, and the number of times the needle was pulled back and redirected (pullbacks) was recorded. Primary outcomes were total time and total number of pullbacks for all 4 lesions. Secondary outcomes were individual time and number of pullbacks for each lesion.ResultsCompared to the freehand group, the IPFA and ENT groups demonstrated lower procedural time and number of pullbacks both in total and for each individual lesion. Differences in total time and total number of pullbacks were significant (P < .001), as were differences for lesion 3 (P = .002–.02) and lesion 4 (P < .001). Differences for lesions 1 and 2 were not statistically significant.ConclusionsRadiology resident procedure time and procedure accuracy (as judged by number of pullbacks) are significantly improved by the use IPFA and ENT guidance technologies.
Regional variability in the atmospheric nitrogen deposition signal and its transfer to the sediment record in Greenland lakes
Authors: Anderson N. J. , Curtis C. J. , Whiteford E. J. , Jones V. J. , McGowan S. , Simpson G. L. , Kaiser J. 
Published: July 2018

AbstractDisruption of the nitrogen cycle is a major component of global environmental change. δ15N in lake sediments is increasingly used as a measure of reactive nitrogen input but problematically, the characteristic depleted δ15N signal is not recorded at all sites. We used a regionally replicated sampling strategy along a precipitation and N‐deposition gradient in SW Greenland to assess the factors determining the strength of δ15N signal in lake sediment cores. Analyses of snowpack N and δ15N‐NO3 and water chemistry were coupled with bulk sediment δ15N. Study sites cover a gradient of snowpack δ15N (ice sheet: −6‰; coast
10‰), atmospheric N deposition (ice sheet margin: ∼ 0.2 kg ha−1 yr−1; coast: 0.4 kg ha−1 yr−1) and limnology. Three 210Pb‐dated sediment cores from coastal lakes showed a decline in δ15N of ca.
1‰ from ∼ 1860, reflecting the strongly depleted δ15N of snowpack N, lower in‐lake total N (TN) concentration (∼ 300 μg N L−1) and a higher TN‐load. Coastal lakes have 3.7–7.1× more snowpack input of nitrate than inland sites, while for total deposition the values are 1.7–3.6× greater for lake and whole catchment deposition. At inland sites and lakes close to the ice‐sheet margin, a lower atmospheric N deposition rate and larger in‐lake TN pool resulted in greater reliance on N‐fixation and recycling (mean sediment δ15N is 0.5–2.5‰ in most inland lakes; n = 6). The primary control of the transfer of the atmospheric δ15N deposition signal to lake sediments is the magnitude of external N inputs relative to the in‐lake N‐pool.
Experiences and perceptions of the theory‐practice gap in nursing in a resource‐constrained setting: A qualitative description study
Authors: Salifu David Abdulai , Gross Janet , Salifu Mohammed Awal , Ninnoni Jerry PK 
Published: July 2018

AbstractAimTo describe experiences and perceptions of theory‐practice gap in nursing in a resource‐constrained setting. Theory‐practice gap is extensively discussed and studied in some parts of the world. Interventions to bridge the theory‐practice gap have been varied and depend on an understanding of the contextual healthcare environment. Experiences and perceptions of the theory‐practice gap in a resource‐constrained setting have not been comprehensively described.DesignA qualitative description methodology was used.MethodsMaximum variation sampling based on role in the events of theory‐practice gap was used to recruit student nurses, nurse faculty and clinicians from two study sites for focus group discussions. Data were analysed using conventional content analysis.ResultsFive themes were identified: system inadequacies; resource constraints; challenges of the clinical learning environment; clinical placement and supervision; and nurse faculty factors. Systems inadequacy and resource constraints formed the spine of the challenges contributing to the theory‐practice gap in the research setting.
Fusarium graminearum‐induced shoot elongation and root reduction in maize seedlings correlate with later seedling blight severity
Authors: Zhou Shaoqun , Bae Justin S. , Bergstrom Gary C. , Jander Georg 
Published: July 2018

AbstractFusarium graminearum seedling blight is a common disease of maize (Zea mays). Development of genetic resistance to seedling blight in maize germplasm requires efficient and accurate quantitative assessment of disease severity. Through artificial inoculation experiments under controlled growth conditions, we determined that host genotype, pathogen genotype, and infection dose influence the extent to which F. graminearum induces shoot elongation and inhibits root growth in maize seedlings. A comparison of 15 maize inbred lines showed independent variation of these two fungus‐induced effects on seedling growth. In a broader survey with nine commercial maize hybrids and three field‐collected fungal isolates, there was significant correlation between these seedling growth responses, as well as with later seedling blight severity. Analysis of variance suggested that this variation and the observed correlative relationships were primarily driven by differing pathogenicity of the three fungal isolates. Together, our results indicate that F. graminearum‐induced shoot elongation and root reduction in maize seedlings have distinct underlying physiological mechanisms, and that early observations of seedling growth responses can serve as a proxy for investigating natural variation in host resistance and pathogen aggressiveness at later growth stages.
Relationship between PSA kinetics and Tc‐99m HYNIC PSMA SPECT/CT detection rates of biochemical recurrence in patients with prostate cancer after radical prostatectomy
Authors: Liu Chang , Zhu Yao , Su Hengchuan , Xu Xiaoping , Zhang Yingjian , Ye Dingwei , Hu Silong 
Published: July 2018

BackgroundProstate‐specific antigen (PSA) levels should reflect or be proportional to the size and the metabolic activity of prostatic metastases. Moreover, a rapid change in PSA kinetics, either before or after treatment, is an indicator of poor prognosis after radical prostatectomy. Therefore, the purpose of this study was to investigate the effect of total PSA at the time of Tc‐99m HYNIC PSMA SPECT/CT (trigger PSA), PSA velocity (PSAvel), and PSA doubling time (PSAdt) on the Tc‐99m HYNIC PSMA SPECT/CT detection rate in prostate cancer patients who showed biochemical recurrence after radical prostatectomy during follow‐up.MethodsIn total, 208 patients who showed an increase in PSA were evaluable for this retrospective analysis covering November 2015 to March 2017. Data were available for calculation of PSAvel in 112 patients and for PSAdt in 157 patients. Logistic regression analysis was used to determine whether there was a relationship between the PSA levels and PSA kinetics and the rate of detection of relapse using Tc‐99m HYNIC PSMA SPECT/CT.ResultsTc‐99m HYNIC PSMA SPECT/CT detected disease relapse in 151 of 208 patients (72.6%). The PSA level (P < 0.0001) and PSAdt (P = 0.0036) were significantly different between SPECT‐positive patients (higher PSA level, shorter PSAdt) and SPECT‐negative patients (lower PSA, longer PSAdt). ROC analysis showed that a PSA level of 1.30 ng/mL and a PSAdt of 2.9 months were optimal cut‐off values. Patients with purely local recurrence had lower PSAvel and longer PSAdt values (P < 0.001). According to the multivariate analysis, a pathological positive SPECT/CT scan was associated with the PSA level (P < 0.001), PSAdt <6 months (P < 0.05), and Gleason scores (GSC) >7 (P < 0.05).ConclusionThe Tc‐99m HYNIC PSMA SPECT/CT detection rate is influenced by trigger PSA, PSAdt, and PSAvel. Like PSA, PSAdt is an independent predictor of Tc‐99m HYNIC PSMA SPECT/CT. PSAdt should be taken into account by physicians especially when PSA <1 ng/mL.
Coil conversion to β‐strand induced by dimerization
Authors: Laibe Johanna , Caffrey Aaron , Broutin Melanie , Guiglion Solene , Pierscionek Barbara , Nebel Jean‐Christophe 
Published: July 2018

AbstractMost molecular processes in living organisms rely on protein‐protein interactions, many of which are mediated by β‐sheet interfaces; this study investigates the formation of β‐sheet interfaces through the conversion of coils into β‐strands. Following an exhaustive search in the Protein Data Bank, the corresponding structural dimorphic fragments were extracted, characterized, and analyzed. Their short strand lengths and specific amino acid profiles indicate that dimorphic β‐strand interfaces are likely to be less stable than standard ones and could even convert to coil interfaces if their environment changes. Moreover, the construction of a simple classifier able to discriminate between the sequences of dimorphic and standard β‐strand interfaces suggests that the nature of those dimorphic sequences could be predicted, providing a novel means of identifying proteins capable of forming dimers.
Evolutionary couplings and sequence variation effect predict protein binding sites
Authors: Schelling Maria , Hopf Thomas A. , Rost Burkhard 
Published: July 2018

AbstractBinding small ligands such as ions or macromolecules such as DNA, RNA, and other proteins is one important aspect of the molecular function of proteins. Many binding sites remain without experimental annotations. Predicting binding sites on a per‐residue level is challenging, but if 3D structures are known, information about coevolving residue pairs (evolutionary couplings) can predict catalytic residues through mutual information. Here, we predicted protein binding sites from evolutionary couplings derived from a global statistical model using maximum entropy. Additionally, we included information from sequence variation. A simple method using a weighted sum over eight scores substantially outperformed random (F1 = 19.3% ± 0.7% vs F1 = 2% for random). Training a neural network on these eight scores (along with predicted solvent accessibility and conservation in protein families) improved substantially (F1 = 26.2% ±0.8%). Although the machine learning was limited by the small data set and possibly wrong annotations of binding sites, the predicted binding sites formed spatial clusters in the protein. The source code of the binding site predictions is available through GitHub: https://github.com/Rostlab/bindPredict.