bluuebunny/crossref_metadata_2025_split huggingface dataset:
South African physician emigration and return migration, 1991–2017: a trend analysis
Authors: Nwadiuko Joseph , Switzer Galen E , Stern Jaime , Day Candy , Paina Ligia 
Published: December 2020

Abstract
Although critical for understanding health labour market trends in low- and middle-income countries (LMICs), longitudinal LMIC health worker emigration and return migration trends are not routinely documented. This article seeks to better understand SA’s trends in physician emigration and return migration and whether economic growth and related policies affect migration patterns. This study used physician registry data to analyse patterns of emigration and return migration only among SA-trained physicians registered to practice in top destination countries such as Australia, Canada, New Zealand, the USA or the UK between 1991 and 2017, which represent the top five emigration destinations for this group. A linear regression model analysed the relationship between migration trends (as dependent variables) and SA’s economic growth, health financing and HIV prevalence (as independent variables). There has been a 6-fold decline in emigration rates from SA between 1991 and 2017 (from 1.8% to 0.3%/year), with declines in emigration to all five destination countries. About one in three (31.8% or 5095) SA physicians returned from destination countries as of 2017. Annual physician emigration fell by 0.16% for every $100 rise in SA GDP per capita (2011 international dollars) (95% confidence interval −0.60% to −0.086%). As of 2017, 21.6% (11 224) of all SA physicians had active registration in destination nations, down from a peak of 33.5% (16 366) in 2005, a decline largely due to return migration. Changes to the UK’s licensing regulations likely affected migration patterns while the Global Code of Practice on International Recruitment contributed little to changes. A country’s economic growth might influence physician emigration, with significant contribution from health workforce policy interventions. Return migration monitoring should be incorporated into health workforce planning.
Paperspray Ionization Mass Spectrometry as a Tool for Predicting Real-Time Optimized Dosing of the Chemotherapeutic Drug Melphalan
Authors: Zhao Junfang , Sharat Chandra , Mehta Parinda A , Mizuno Kana , Vinks Alexander A , Setchell Kenneth D R 
Published: December 2020

Abstract

Background
Melphalan, an important component of hematopoietic stem cell transplantation (HSCT) preparative regimens, is associated with significant toxicity and large between patient variability in pharmacokinetics making it difficult to calculate the optimal dose for pediatric patients. Paperspray (PS) ionization generates gas phase analyte ions directly from a dried blood spot without the need for prior sample preparation or chromatography. With these advantages, a validated PS–MS/MS assay was developed and applied to the ‘real-time’ determination of melphalan pharmacokinetics (PK).

Methods
Melphalan was quantified by stable-labeled isotope dilution analysis in whole blood by PS–MS/MS. Blood samples were obtained at timed intervals from patients during HSCT after administration of a very low (test) dose of melphalan to avoid toxicity. Pharmacokinetics parameters were calculated using WinNonlin v.6.4. From these data, the optimal therapeutic dose was estimated and full dose PK repeated.

Results
PS–MS/MS method was linear over a large dynamic range (25–50 000 ng/mL), intra- and interassay reproducibility of quality control samples was &lt;15% CV. With essentially no prior sample preparation, PS–MS/MS measurement of blood melphalan concentrations showed excellent correlation (R2 = 0.959, n = 62) with a validated electrospray–LC–MS/MS method. Trapezoidal area under the curves calculated for 5 patients administered low dose melphalan showed a high linear correlation (R2 = 0.981) between the PS–MS/MS and LC–MS/MS methods. The faster PS approach permitted real-time PK evaluation of individual patients.

Conclusions
A validated PS–MS/MS assay for melphalan in patients undergoing HSCT is described that facilitates pharmacokinetic-guided individualized precision dosing with immediate bedside dose adjustments to improve outcomes by balancing toxicity and efficacy of melphalan.
External validation of the albumin, C-reactive protein and lactate dehydrogenase model in patients with metastatic renal cell carcinoma receiving second-line axitinib therapy in a Japanese multi-center cohort
Authors: Tamura Keita , Osawa Takahiro , Takeuchi Ario , Minami Keita , Nakai Yasutomo , Ueda Kosuke , Ozawa Michinobu , Uemura Motohide , Sugimoto Mikio , Ohba Kojiro , Suzuki Toshihiro , Anai Satoshi , Shindo Tetsuya , Kusakabe Naohisa , Komiyama Motokiyo , Tanaka Ken , Yokomizo Akira , Kohei Naoki , Shinohara Nobuo , Miyake Hideaki ,   Japanese Urological Oncology Group
Published: December 2020

Abstract

Purpose
To externally validate the utility of the albumin, C-reactive protein and lactate dehydrogenase model to predict the overall survival of previously treated metastatic renal cell carcinoma patients.

Patients and methods
The ability of the albumin, C-reactive protein and lactate dehydrogenase model to predict overall survival was validated and compared with those of other prognostication models using data from 421 metastatic renal cell carcinoma patients receiving second-line axitinib therapy at 36 hospitals belonging to the Japan Urologic Oncology Group.

Results
The following factors in this cohort were independently associated with poor overall survival in a multivariate analysis: a low Karnofsky performance status, &lt;1 year from diagnosis to targeted therapy, a high neutrophil count, and low albumin, elevated C-reactive protein, and elevated lactate dehydrogenase, and the Japan Urologic Oncology Group model was newly developed based on the presence/absence of these independent factors. In this cohort, 151 (35.9%), 125 (27.7%) and 145 (34.4%) patients were classified into the favorable, intermediate and poor risk groups, respectively, according to the albumin, C-reactive protein and lactate dehydrogenase model; however, the proportions of patients in the intermediate risk group stratified by the Japan Urologic Oncology Group, Memorial Sloan Kettering Cancer Center and International Metastatic Renal Cell Carcinoma Database Consortium models were &gt;50%. The superiority of the albumin, C-reactive protein and lactate dehydrogenase model to the Memorial Sloan Kettering Cancer Center and International Metastatic Renal Cell Carcinoma Database Consortium models, but not the Japan Urologic Oncology Group model, was demonstrated by multiple statistical analyses.

Conclusions
The utility of the albumin, C-reactive protein and lactate dehydrogenase model as a simple and objective prognostication tool was successfully validated using data from 421 metastatic renal cell carcinoma patients receiving second-line axitinib.
Possibilities for and limits of upfront surgical strategy with lateral pelvic node dissection for low rectal cancer
Authors: Ouchi Akira , Komori Koji , Kinoshita Takashi , Oshiro Taihei , Kunitomo Aina , Ito Seiji , Abe Tetsuya , Shimizu Yasuhiro 
Published: December 2020

Abstract

Background
Metastatic lateral pelvic nodes represent an important cause of pelvic recurrence in low rectal cancer patients even after preoperative chemoradiotherapy. This study aimed to evaluate the prognostic benefit of an upfront lateral pelvic nodes dissection strategy.

Methods
A total of 175 consecutive patients with stage II/III low rectal adenocarcinoma who underwent mesorectal excision with lateral pelvic nodes dissection between 1998 and 2013 were identified. Regional lateral pelvic nodes were categorized as LD2 nodes (internal iliac, hypogastric and obturator) and LD3 nodes (external iliac, common iliac, lateral sacral, presacral and sacral promontory) according to the current Japanese Society for Cancer of the Colon and Rectum classification.

Results
Five-year cumulative risks of local recurrence and recurrence-free survival were 4.8% and 78.1% for stage II patients, and 11.8% and 61.7% for stage III patients, respectively. Among stage III patients, no differences were observed in cumulative risks of local recurrence (5 years: 9.3% vs 14.7%, P= 0.463) and recurrence-free survival (5 years: 65.1 vs 61.2%, P = 0.890) between lateral pelvic nodes (−) and LD2 (+) patients. In multivariate analyses, metastatic lateral pelvic nodes had no impact on cumulative risks of local recurrence (hazard ratioadj: 1.389; 95% confidence interval: 0.409–4.716) and recurrence-free survival (hazard ratioadj: 0.884; 95% confidence interval: 0.425–1.837).

Conclusions
Metastatic lateral pelvic nodes had no impact on cumulative risks of local recurrence and recurrence-free survival based on an upfront lateral pelvic nodes strategy. Lateral pelvic nodes can improve recurrence and survival outcomes in locally advanced low rectal cancer patients with metastatic lateral pelvic nodes.
A search for trends in spatially resolved debris discs at far-infrared wavelengths
Authors: Marshall J P , Wang L , Kennedy G M , Zeegers S T , Scicluna P 
Published: December 2020

ABSTRACT
Debris discs around main-sequence stars are belts of planetesimals – asteroids and comets – formed in the protoplanetary discs around young stars. Planetesimals comprise both the building blocks of planets around young stars and the source of dusty debris around older stars. Imaging observations of dust continuum emission and scattered light reveal the location of these planetesimal belts around their host stars. Analysis of debris discs observed at millimetre wavelengths revealed a trend between the discs’ radii and the host star luminosities. This trend was tentatively linked to the preferential formation of dust-producing planetesimals near snow lines (specifically CO) in the protoplanetary discs around the host stars. Here, we perform a homogeneous analysis of 95 debris discs observed at far-infrared wavelengths by the Herschel Space Observatory and fit the obtained distribution of radii and widths as a function of stellar luminosity with a power-law relation. We identify a trend in disc radius as a function of stellar luminosity similar to that identified at millimetre wavelengths, but cannot convincingly recover it from the available data set due to the large uncertainties on disc radius and width inherent in the marginally spatially resolved data, and the bias of smaller discs around more distant stars (which are also the more luminous) being omitted from our analysis. We see a trend in disc temperature as a function of stellar luminosity, consistent with previous findings from similar analyses.
Simulations of radiation-driven winds from Keplerian discs
Authors: Raychaudhuri Sananda , Vyas Mukesh K , Chattopadhyay Indranil 
Published: December 2020

ABSTRACT
We study the ejection of winds from thin accretion discs around stellar mass black holes and the time evolution of these winds in the presence of radiation field generated by the accretion disc. Winds are produced by radiation, thermal pressure, and the centrifugal force of the disc. The winds are found to be mildly relativistic, with speeds reaching up to terminal speeds of 0.1 for accretion rate of 4 in Eddington units. We show that the ejected matter gets its rotation by transporting angular momentum from the disc to the wind. We also show that the radiation drag affects the accretion disc winds in a very significant manner. Not only that the terminal speeds are reduced by an order of magnitude due to radiation drag, but we also show that the non-linear effect of radiation drag can mitigate the formation of the winds from the matter ejected by the accretion disc. As radiation drag reduces the velocity of the wind, the mass outflow rate is reduced in its presence as well.
Group-scale intrinsic galaxy alignments in the Illustris-TNG and MassiveBlack-II simulations
Authors: Tenneti Ananth , Kitching Thomas D , Joachimi Benjamin , Di Matteo Tiziana 
Published: December 2020

ABSTRACT
We study the alignments of satellite galaxies, and their anisotropic distribution, with respect to location and orientation of their host central galaxy in MassiveBlack-II (MB-II) and IllustrisTNG simulations. We find that: the shape of the satellite system in haloes of mass ($\gt 10^{13}\, h^{-1}\, \mathrm{M}_{\odot }$) is well aligned with the shape of the central galaxy at z = 0.06 with the mean alignment between the major axes being ∼Δθ = 12° when compared to a uniform random distribution; that satellite galaxies tend to be anisotropically distributed along the major axis of the central galaxy with a stronger alignment in haloes of higher mass or luminosity; and that the satellite distribution is more anisotropic for central galaxies with lower star formation rate, which are spheroidal, and for red central galaxies. Radially, we find that satellites tend to be distributed along the major axis of the shape of the stellar component of central galaxies at smaller scales and the dark matter component on larger scales. We find that the dependence of satellite anisotropy on central galaxy properties and the radial distance is similar in both the simulations with a larger amplitude in MB-II. The orientation of satellite galaxies tends to point toward the location of the central galaxy at small scales and this correlation decreases with increasing distance, and the amplitude of satellite alignment is higher in high-mass haloes. However, the projected ellipticities do not exhibit a scale-dependent radial alignment, as has been seen in some observational measurements.
Do we need non-ideal magnetohydrodynamic to model protostellar discs?
Authors: Wurster James 
Published: December 2020

ABSTRACT
We investigate and discuss protostellar discs in terms of where the various non-ideal magnetohydrodynamics (MHD) processes are important. We find that the traditional picture of a magnetized disc (where Ohmic resistivity is dominant near the mid-plane, surrounded by a region dominated by the Hall effect, with the remainder of the disc dominated by ambipolar diffusion) is a great oversimplification. In simple parametrized discs, we find that the Hall effect is typically the dominant term throughout the majority of the disc. More importantly, we find that in much of our parametrized discs, at least two non-ideal processes have coefficients within a factor of 10 of one another, indicating that both are important and that naming a dominant term underplays the importance of the other terms. Discs that were self-consistently formed in our previous studies are also dominated by the Hall effect, and the ratio of ambipolar diffusion and Hall coefficients is typically less than 10, suggesting that both terms are equally important and listing a dominant term is misleading. These conclusions become more robust once the magnetic field geometry is taken into account. In agreement with the literature we review, we conclude that non-ideal MHD processes are important for the formation and evolution of protostellar discs. Ignoring any of the non-ideal processes, especially ambipolar diffusion and the Hall effect, yields an incorrect description of disc evolution.
Biophysical optimization of preimplantation embryo culture: what mechanics can offer ART
Authors: Hawkins Jamar , Miao Xiaosu , Cui Wei , Sun Yubing 
Published: December 2020

Abstract
Owing to the rise of ART and mounting reports of epigenetic modification associated with them, an understanding of optimal embryo culture conditions and reliable indicators of embryo quality are highly sought after. There is a growing body of evidence that mechanical biomarkers can rival embryo morphology as an early indicator of developmental potential and that biomimetic mechanical cues can promote healthy development in preimplantation embryos. This review will summarize studies that investigate the role of mechanics as both indicators and promoters of mammalian preimplantation embryo development and evaluate their potential for improving future embryo culture systems.
Comparison of loop extrusion and diffusion capture as mitotic chromosome formation pathways in fission yeast
Authors: Gerguri Tereza , Fu Xiao , Kakui Yasutaka , Khatri Bhavin S , Barrington Christopher , Bates Paul A , Uhlmann Frank 
Published: December 2020

AbstractUnderlying higher order chromatin organization are Structural Maintenance of Chromosomes (SMC) complexes, large protein rings that entrap DNA. The molecular mechanism by which SMC complexes organize chromatin is as yet incompletely understood. Two prominent models posit that SMC complexes actively extrude DNA loops (loop extrusion), or that they sequentially entrap two DNAs that come into proximity by Brownian motion (diffusion capture). To explore the implications of these two mechanisms, we perform biophysical simulations of a 3.76 Mb-long chromatin chain, the size of the long Schizosaccharomyces pombe chromosome I left arm. On it, the SMC complex condensin is modeled to perform loop extrusion or diffusion capture. We then compare computational to experimental observations of mitotic chromosome formation. Both loop extrusion and diffusion capture can result in native-like contact probability distributions. In addition, the diffusion capture model more readily recapitulates mitotic chromosome axis shortening and chromatin compaction. Diffusion capture can also explain why mitotic chromatin shows reduced, as well as more anisotropic, movements, features that lack support from loop extrusion. The condensin distribution within mitotic chromosomes, visualized by stochastic optical reconstruction microscopy (STORM), shows clustering predicted from diffusion capture. Our results inform the evaluation of current models of mitotic chromosome formation.
Unique Peripheral Antennas in the Photosystems of the Streptophyte Alga Mesostigma viride
Authors: Aso Michiki , Matsumae Renon , Tanaka Ayumi , Tanaka Ryouichi , Takabayashi Atsushi 
Published: December 2020

Abstract
Land plants evolved from a single group of streptophyte algae. One of the key factors needed for adaptation to a land environment is the modification in the peripheral antenna systems of photosystems (PSs). Here, the PSs of Mesostigma viride, one of the earliest-branching streptophyte algae, were analyzed to gain insight into their evolution. Isoform sequencing and phylogenetic analyses of light-harvesting complexes (LHCs) revealed that M. viride possesses three algae-specific LHCs, including algae-type LHCA2, LHCA9 and LHCP, while the streptophyte-specific LHCB6 was not identified. These data suggest that the acquisition of LHCB6 and the loss of algae-type LHCs occurred after the M. viride lineage branched off from other streptophytes. Clear-native (CN)-polyacrylamide gel electrophoresis (PAGE) resolved the photosynthetic complexes, including the PSI–PSII megacomplex, PSII–LHCII, two PSI–LHCI–LHCIIs, PSI–LHCI and the LHCII trimer. Results indicated that the higher-molecular weight PSI–LHCI–LHCII likely had more LHCII than the lower-molecular weight one, a unique feature of M. viride PSs. CN-PAGE coupled with mass spectrometry strongly suggested that the LHCP was bound to PSII–LHCII, while the algae-type LHCA2 and LHCA9 were bound to PSI–LHCI, both of which are different from those in land plants. Results of the present study strongly suggest that M. viride PSs possess unique features that were inherited from a common ancestor of streptophyte and chlorophyte algae.
Cognitive Processing Speed Impairment Does Not Influence the Construct Validity of Six-Spot Step Test Performance in People With Multiple Sclerosis
Authors: Sandroff Brian M , Silveira Stephanie L , Baird Jessica F , Huynh Trinh , Motl Robert W 
Published: December 2020

Abstract

Objective
There is evidence supporting the construct validity of Six-Spot Step Test (SSST) performance as a functional mobility measure in people with multiple sclerosis (MS); however, it is unknown if cognitive processing speed impairment confounds the construct validity of SSST performance in MS, as this test seemingly requires intact cognitive processing. The objective of this study was to examine the influence of cognitive processing speed impairment on the construct validity and precision of SSST performance as a functional mobility measure in MS.

Methods
Participants (N = 213) completed the SSST, timed 25-foot walk, 6-Minute Walk Test, Timed “Up and Go” Test, Multiple Sclerosis Walking Scale-12, device-measured steps per day, and Late-Life Function and Disability Inventory, Patient-Determined Disease Steps, and the Symbol-Digit Modalities Test as a cognitive processing speed measure. The overall sample was divided into subsamples with (n = 75) and without (n = 138) cognitive processing speed impairment based on normative Symbol-Digit Modalities Test data. Correlations between SSST performance with other mobility outcomes in the overall sample and cognitive processing speed impairment subsamples were examined and compared. SSST performance was compared relative to other mobility measures for differentiating MS walking function levels in people with and without cognitive processing speed impairment.

Results
SSST performance was significantly and strongly correlated with most mobility outcomes in the overall sample and cognitive processing speed impairment subsamples. The magnitudes of correlations between SSST performance with most mobility outcomes were not statistically different among subsamples. Cognitive processing speed impairment did not diminish the relative precision of SSST performance for differentiating walking function levels.

Conclusion
The presence of cognitive processing speed impairment is not a source of invalidity or imprecision when interpreting SSST performance as a functional mobility measure among people with MS.

Impact
The SSST is a high-quality endpoint for inclusion in interventions targeting mobility in MS, regardless of cognitive processing speed status. This information is critical for rehabilitation research and clinical practice given that mobility and cognitive impairment are highly prevalent, co-occurring, and disabling in MS.
How can we help? Medical students’ views on their role in the COVID-19 pandemic
Authors: Michno D A , Tan J , Adelekan A , Konczalik W , Woollard A C S 
Published: December 2020

AbstractBackgroundThe ongoing COVID-19 pandemic has resulted in a sharp rise in demand for healthcare workers worldwide. This has been coupled with reduced numbers of available medical professionals due to confirmed or suspected infections with SARS-CoV-2. To counteract these shortages, governments of several countries have considered the enrolment of medical students into the workforce in order to help to tackle the ongoing crisis.MethodsQuestionnaire-based study assessing the perceived role of medical students in assisting in the COVID-19 pandemic. The primary aim was to determine factors contributing to the willingness of medical students to actively assist in the pandemic. The secondary aim was to evaluate their perspectives regarding the associated changes in medical education.ResultsOut of 760 responses, 71.18% of medical students were willing to assist the medical workforce during the pandemic. Clinical year students were more likely to help in a medical capacity than pre-clinical students (OR = 0.384, 95%CI [0.167, 0.883, P &lt; 0.05)]. Respondents concerned about their own well-being were less likely to engage in clinical work (OR = 0.680, 95%CI [0.491, 0.941], P &lt; 0.020). Students who agreed that online lectures will negatively impact their education were inclined to think that the academic year should be extended (95%CI [0.065, 0.271], P = 0.001).ConclusionsMost students are willing to help in both a medical and non-medical capacity. Their primary concerns when working in a medical setting are the risk of infecting their relatives and patients, lack of protective equipment and necessary knowledge as well as legal uncertainty whilst working without a medical qualification.