bluuebunny/crossref_metadata_2025 huggingface dataset:
Bond dissociation energies of diatomic transition metal nitrides
Authors: Merriles Dakota M. , Knapp Annie S. , Barrera-Casas Yexalen , Sevy Andrew , Sorensen Jason J. , Morse Michael D.
Published: February 2023

Resonant two-photon ionization (R2PI) spectroscopy has been used to measure the bond dissociation energies (BDEs) of the diatomic transition metal nitrides ScN, TiN, YN, MoN, RuN, RhN, HfN, OsN, and IrN. Of these, the BDEs of only TiN and HfN had been previously measured. Due to the many ways electrons can be distributed among the d orbitals, these molecules possess an extremely high density of electronic states near the ground separated atom limit. Spin–orbit and nonadiabatic interactions couple these states quite effectively, so that the molecules readily find a path to dissociation when excited above the ground separated atom limit. The result is a sharp drop in ion signal in the R2PI spectrum when the molecule is excited above this limit, allowing the BDE to be readily measured. Using this method, the values D0(ScN) = 3.905(29) eV, D0(TiN) = 5.000(19) eV, D0(YN) = 4.125(24) eV, D0(MoN) = 5.220(4) eV, D0(RuN) = 4.905(3) eV, D0(RhN) = 3.659(32) eV, D0(HfN) = 5.374(4) eV, D0(OsN) = 5.732(3) eV, and D0(IrN) = 5.115(4) eV are obtained. To support the experimental findings, ab initio coupled-cluster calculations extrapolated to the complete basis set limit (CBS) were performed. With a semiempirical correction for spin–orbit effects, these coupled-cluster single double triple-CBS calculations give a mean absolute deviation from the experimental BDE values of 0.20 eV. A discussion of the periodic trends, summaries of previous work, and comparisons to isoelectronic species is also provided.
Simulation of thermal decomposition of γ′-Fe4N using molecular dynamics method
Authors: Zhu Jianxin , Wang Jian-Ping
Published: February 2023

α″-Fe16N2 is a promising environmentally friendly rare-earth-free permanent magnet material with ultra-high saturation magnetization. Recent research has demonstrated experimentally through a thermally quenching treatment using γ′ phase Fe4N as a precursor to synthesize α″-Fe16N2 in bulk format. In this research using Molecular Dynamics (MD) simulation, we investigated the γ′-Fe4N phase thermal decomposition process and the potential phase transition from face center cubic (fcc)-phase to body center tetragonal (bct)-phase. As nitrogen concentration is higher in γ′-Fe4N (5.9 wt. %) than that in α′-Fe8N or α″-Fe16N2 (3 wt. %), Nitrogen bond formation through atom diffusion is studied with a “Nitrogen-rich” grain boundary (GB) model to find out whether lower-Nitrogen content bct Fe–N solid solution can be formed. Modified Embedded Atom Method (MEAM) interatomic potential of Fe–N system is applied. Post-processing including Nitrogen bond mapping/tracking is also performed for the thermostat-controlled heating and quenching simulation process. We also applied virtual XRD computation to characterize the material crystallographic texture before and after the thermal treatment.
Social Frailty Index: Development and validation of an index of social attributes predictive of mortality in older adults
Authors: Shah Sachin J. , Oreper Sandra , Jeon Sun Young , Boscardin W. John , Fang Margaret C. , Covinsky Kenneth E.
Published: February 2023

While social characteristics are well-known predictors of mortality, prediction models rely almost exclusively on demographics, medical comorbidities, and function. Lacking an efficient way to summarize the prognostic impact of social factor, many studies exclude social factors altogether. Our objective was to develop and validate a summary measure of social risk and determine its ability to risk-stratify beyond traditional risk models. We examined participants in the Health and Retirement Study, a longitudinal, survey of US older adults. We developed the model from a comprehensive inventory of 183 social characteristics using least absolute shrinkage and selection operator, a penalized regression approach. Then, we assessed the predictive capacity of the model and its ability to improve on traditional prediction models. We studied 8,250 adults aged ≥65 y. Within 4 y of the baseline interview, 22% had died. Drawn from 183 possible predictors, the Social Frailty Index included age, gender, and eight social predictors: neighborhood cleanliness, perceived control over financial situation, meeting with children less than yearly, not working for pay, active with children, volunteering, feeling isolated, and being treated with less courtesy or respect. In the validation cohort, predicted and observed mortality were strongly correlated. Additionally, the Social Frailty Index meaningfully risk-stratified participants beyond the Charlson score (medical comorbidity index) and the Lee Index (comorbidity and function model). The Social Frailty Index includes age, gender, and eight social characteristics and accurately risk-stratifies older adults. The model improves upon commonly used risk prediction tools and has application in clinical, population health, and research settings.
Inside the echo chamber
Authors: Cheng Xi
Published: February 2023

In the context of the China-USA trade dispute, this study reports a discourse analysis of legitimation tactics used in the People’s Daily, a major English-language news outlet produced by the Communist Party of China (CPC). My analysis centres on a dataset of 65 commentaries between March 2018 and January 2020, and identifies the five key tactics at work: authorization, moralization, rationalization, hypothetical future, and integration. These tactics (and their sub-tactics) are deployed for delegitimating the US-initiated “America First” trade policy, and for legitimating the Chinese state’s position and countermeasures. Orienting to Western scholarship about the news media’s role as an “echo chamber” for State/political agendas, I compare the pattern of legitimation in the People’s Daily commentaries with the pattern previously found in an analysis of Chinese state white papers. This comparison highlights key similarities but also differences in terms of genre, language, and ideological coherence.
Dynamics of charged hyperbolically symmetric matter in modified gravity
Authors: Bhatti M Z , Yousaf Z , Tariq Z
Published: February 2023

We have conducted an in-depth investigation of static anisotropic matter configurations surrounded by electromagnetic field and possessing hyperbolically symmetric geometry by examining their physical characteristics in the framework of Palatini version of f(R) gravitational theory. Choosing the comoving coordinates, we define a canonical orthonormal tetrad and obtain the components of stress-energy tensor in locally Minkowskian frame. Working out the Palatini–Maxwell equations and the interior mass function for such a symmetry, it comes out that the energy density appears as a negative quantity which results in the development of a vacuole in the vicinity of the central region of the symmetry depicting that this region cannot be occupied by matter. We have also assessed the hydrostatic equilibrium equation and the source of tidal forces for the symmetry (i.e. Weyl scalar) and the active gravitational mass. Few scalar functions are then obtained out of the orthogonal decomposition of the Riemann curvature tensor and are utilized for the comprehension of physical characteristics of the matter configuration. Certain explicit solutions to the Palatini–Maxwell equations are also rendered with the help of two physical variables acting as generating functions.
Medical gamma cameras in radiological emergency preparedness: determination of calibration factors and MDA for the GE Discovery NM/CT 670 Pro
Authors: Hjellström Martin , Isaksson Mats
Published: February 2023

A survey was performed of the available gamma camera models and whole-body counters (WBCs) in Sweden, revealing that there are about 75 gamma cameras and 15 WBCs currently in operation in Sweden. One of the most common gamma camera models (GE Discovery NM/CT 670 Pro), with the collimators removed, was calibrated for 152Eu, 137Cs, 60Co and 40K in three different measurement geometries (supine, close-up sitting and distant sitting) for six different phantom sizes (12–110 kg). Minimum detectable activities (MDAs) were calculated for the gamma camera and a typical WBC, both at the Sahlgrenska University Hospital in Gothenburg, Sweden. An energy window of 30–510 keV was used to calibrate the gamma camera. The calibration factors for this gamma camera for supine and close-up sitting geometry, including all phantom sizes, were 138–208 cps kBq−1 for 152Eu, 63–83 cps kBq−1 for 137Cs and 99–126 cps kBq−1 for 60Co; the MDAs were 50–73 Bq for 152Eu, 125–198 Bq for 137Cs and 83–105 Bq for 60Co. The International Commission on Radiological Protection dose coefficients for members of the public were used to calculate the committed effective doses (CEDs) corresponding to the MDAs, showing that CEDs down to a few μSv can be estimated with this gamma camera for the inhalation of aerosols of absorption type M. The distant sitting geometry was used to enable the estimation of higher contamination levels, and a hypothetical maximum CED was calculated. This was shown to be 256–2000 mSv, depending on the radionuclide and phantom size. However, further investigations are needed into the dead time losses for higher activity levels for the radionuclides studied. The results show that the use of gamma cameras for radiological triage and, in some cases, to estimate the internal activity of relevant radionuclides in radiological and nuclear events, is feasible.
Defect detection algorithm for magnetic particle inspection of aviation ferromagnetic parts based on improved DeepLabv3+
Authors: Zeng Lu , Zhang Shouming , Wang Pengju , Li Zuze , Hu Yongjin , Xie Tao
Published: February 2023

Non-destructive testing (NDT) of magnetic materials such as aviation parts is an indispensable part of the civil aviation maintenance industry. The NDT of such metal materials often uses magnetic particle inspection (MPI) technology. This paper proposes an improved DeepLabv3+ semantic segmentation algorithm for automatic defect detection of aviation ferromagnetic parts after MPI. In the network structure, lightweight MobileNetV2 is the backbone feature extraction network. The dense atrous spatial pyramid pooling (DenseASPP) structure is used to strengthen feature extraction. The influence of three different DenseASPP structures on the recognition effect is compared in the experiment. At the same time, the decoder is further optimized. The experimental results show that the Ours-DeepLabv3+ network model can effectively for automatic defect detection of aviation ferromagnetic parts after MPI. The Precision, Recall, F1-score, and intersection over union are 81.64%, 83.12%, 82.37%, and 71.23%, respectively, which are 7.48%, 5.45%, 6.50%, and 10.1% higher than the original DeepLabv3+, and defect detail segmentation is more accurate. Compared with other semantic segmentation algorithms, this method can effectively improve the accuracy of defect detection of aviation ferromagnetic parts and meet the requirements of defect detection.
The twisted baker map
Authors: Saiki Yoshitaka , Takahasi Hiroki , Yorke James A
Published: February 2023

As a model to provide a hands-on, elementary understanding of ‘vortex dynamics’, we introduce a piecewise linear non-invertible map called a twisted baker map. We show that the set of hyperbolic repelling periodic points with complex conjugate eigenvalues and that without complex conjugate eigenvalues are simultaneously dense in the phase space. We also show that these two sets equidistribute with respect to the normalised Lebesgue measure, in spite of a non-uniformity in their Lyapunov exponents.
New linear stability parameter to describe low-β electromagnetic microinstabilities driven by passing electrons in axisymmetric toroidal geometry
Authors: Hardman M R , Parra F I , Patel B S , Roach C M , Ruiz Ruiz J , Barnes M , Dickinson D , Dorland W , Parisi J F , St-Onge D , Wilson H
Published: February 2023

In magnetic confinement fusion devices, the ratio of the plasma pressure to the magnetic field energy, β, can become sufficiently large that electromagnetic microinstabilities become unstable, driving turbulence that distorts or reconnects the equilibrium magnetic field. In this paper, a theory is proposed for electromagnetic, electron-driven linear instabilities that have current layers localised to mode-rational surfaces and binormal wavelengths comparable to the ion gyroradius. The model retains axisymmetric toroidal geometry with arbitrary shaping, and consists of orbit-averaged equations for the mode-rational surface layer, with a ballooning space kinetic matching condition for passing electrons. The matching condition connects the current layer to the large scale electromagnetic fluctuations, and is derived in the limit that β is comparable to the square root of the electron-to-ion-mass ratio. Electromagnetic fluctuations only enter through the matching condition, allowing for the identification of an effective β that includes the effects of equilibrium flux surface shaping. The scaling predictions made by the asymptotic theory are tested with comparisons to results from linear simulations of micro-tearing and electrostatic microinstabilities in MAST discharge #6252, showing excellent agreement. In particular, it is demonstrated that the effective β can explain the dependence of the local micro-tearing mode (MTM) growth rate on the ballooning parameter θ
0–possibly providing a route to optimise local flux surfaces for reduced MTM-driven transport.
Design of step-graded AlGaN buffers for GaN-on-Si heterostructures grown by MOCVD
Authors: Ghosh Saptarsi , Hinz Alexander M , Frentrup Martin , Alam Saiful , Wallis David J , Oliver Rachel A
Published: February 2023

For the growth of low-defect crack-free GaN heterostructures on large-area silicon substrates, compositional grading of AlGaN is a widely adapted buffer technique to restrict the propagation of lattice-mismatch induced defects and balance the thermal expansion mismatch-induced tensile stress. So far, a consolidation of the design strategy of such step-graded buffers has been impaired by the incomplete understanding of the effect of individual buffer design parameters on the mechanical and microstructural properties of the epilayers. Herein, we have analyzed a series of metal-organic chemical vapor deposition grown GaN/graded-AlGaN/AlN/Si heterostructures through in situ curvature measurements and post-growth x-ray diffraction (XRD). Our results reveal that in such epi structures, the GaN layer itself induces more compressive stress than the AlGaN buffer, but the underlying AlGaN layers dictate the magnitude of this stress. Furthermore, for a fixed AlGaN buffer thickness, the mean-stress accumulated during the GaN growth is found to be correlated with its structural properties. Specifically, one µm thick GaN layers that acquire 1.50 GPa or higher compressive mean-stress are seen to possess

20

2
ˉ

1

XRD ω-FWHM values less than 650 arc-sec. Also, the evolution of instantaneous stresses during the growth of the AlGaN layers is found to be a valuable indicator for buffer optimization, and composition difference between successive layers is established as a crucial criterion. The results also show that increasing the total buffer thickness (for a fixed number of steps) or increasing the number of steps (for a fixed total buffer thickness) may not always be beneficial. Irrespective of the buffer thickness, optimized high electron mobility transistor structures show similarly low sheet-resistance (∼350 Ω □)−1 and high mobility (∼2000 cm2 V−1 s −1) at room temperature.
Viscous cosmology in holographic dark energy with Granda–Oliveros cut-off
Authors: Kaur Simran , Singh C P
Published: February 2023

We study the effect of bulk viscosity on holographic dark energy (HDE) with Granda–Oliveros infra-red cut-off. We focus on a generalized form of the bulk viscous coefficient which successfully describes the present-day evolution of the Universe. We observe that the model with bulk viscosity provides an elegant description of the early and late-time evolution of the Universe. We constrain the model through the combined observational data of the Strong Lensing System (SLS), measurements of Hubble parameter, Type Ia supernova data of Pantheon sample and local H
0 measured by SH0ES. Using best-fit values obtained from two different combinations of data, we estimate the present value of Hubble’s constant

H

0

=

71.567

−
0.848

+
1.448

and

H

0

=

69.197

−
1.924

+
1.563

, the deceleration parameter

q

0

=
−

0.535

−
0.016

+
0.016

and

q

0

=
−

0.536

−
0.016

+
0.016

, and the equation of state

ω

0

=
−

0.690

−
0.010

+
0.010

and

ω

0

=
−

0.691

−
0.011

+
0.011

, respectively. The HDE model with bulk viscosity exhibits the phase transition from decelerated epoch to accelerated epoch. A comparison of the model with the standard ΛCDM model is discussed with the statefinder and cosmographic parameters.
Analysis and characterization of CdTe material surface defects
Authors: Bezak M. , Bharthuar S. , Brücken E. , Gädda A. , Golovleva M. , Kalliokoski M. , Kirschenmann S. , Luukka P. , Ott J.
Published: February 2023

To study the impact of various defects associated close to the surface layer of CdTe material, we use scanning laser Transient Current Technique. This gives us an overview of different compositional inhomogeneities, such as dislocations, grain boundaries, and tellurium inclusions. Particularly, reconstructed high resolution spatial images provide a map of different electrically active defects. Each spatial point contains a recording of a current pulse, from which shape we calculate drift times and total collected charge. Charge mobility and charge loss are extracted from current pulses and show the effects of charge trapping and polarization. In addition, we investigate the impact of the ALD alumina-CdTe interface and negative fixed charge trapping using both passivated and non-passivated CdTe crystals.
LHCb VELO fast calibration
Authors: Fernández Prieto A.
Published: February 2023

During the long shutdown 2 of the LHC, the LHCb Experiment was upgraded to a trigger-less system reading out the full detector at 40 MHz bunch crossing rate with all selection algorithms executed in a CPU farm. The upgraded Vertex Locator (VELO) of the LHCb is a hybrid pixel detector read out by the “VeloPix” front-end ASIC with on-chip zero-suppression. This paper describes a novel way of calibrating the VELO detector based on dedicated threshold scan firmware. The firmware is implemented in the control and data acquisition back-end boards of the detector. This threshold scan method has multiple advantages compared with the default one: it is faster as the algorithm was moved from software to firmware, it is more deterministic by minimizing software interruptions and data transfer and it is more precise by reducing noise due to ASIC operation.
LAPPD operation using ToFPETv2 PETSYS ASIC
Authors: Seljak A. , Bračko M. , Dolenec R. , Križan P. , Lozar A. , Pestotnik R. , Korpar S.
Published: February 2023

Single photon sensitive detectors used in high energy physics are, in some applications, required to cover areas the size of several m2, and more specifically in very strong demand with an ever finer imaging and timing capability for Cherenkov Ring Imaging Detector (RICH) configurations. We are evaluating the Large Area Picosecond Photo-detector (LAPPD) produced by INCOM company, as a possible candidate for future RICH detector upgrades. In this work we perform tests on the second generation device, which is capacitively coupled to a custom designed anode back plane, consisting of various pixels and strips varying in size, that allows for connecting various readout systems such as standard laboratory equipment, as well as the TOFPET2 ASIC from PETsys company. Our aim is to evaluate what can be achieved by merging currently available technology, in order to find directions for future developments adapted for specific uses.
Large area hybrid detectors based on Medipix3RX: commissioning and characterization at Sirius beamlines
Authors: Campanelli R.B. , Gomes G.S. , Fernandes M.G. , Mendes L.H. , Rosa L.B. , Reis R.C. , Antonio E.B. , Polli J.M.
Published: February 2023

Hybrid pixel detectors are inherently modular and typically operate at relative low noise levels, while providing high spatial resolution, easing the assembling of large area detectors. This report summarizes the procedures and results regarding the characterization studies performed on the Medipix3RX ASIC based detector, known as PIMEGA, which was developed and is deployed at Sirius synchrotron facility at the Brazilian Synchrotron Light Laboratory. They consist of modular constructions that reach up to 170 × 170 mm2 of active area, with 300 µm thick silicon sensors, and pixel size of 55 × 55 µm2. We investigated the spatial and energy resolutions, structural noise properties, and count-rate linearity up to large fluxes from the synchrotron beamlines. The Modulation Transfer Function presents a considerably slow decay rate as a function of the spatial frequency, reaching 30% at 10.5 lp/mm, for an operation with a threshold setting equivalent to half of the incident energy. We have also found that the energy resolutions of the two highest gain modes are around 15% for 17.5 keV incident photons. In particular, we have found that, for a noise-suppressing set of configurations, the detector presents a dead time of 460 ± 10 ns. Additionally, the pile-up effect leads to a 10% loss of linearity at input fluxes of 2.3 × 105 photons/pixel.s. These results open the possibility for operating these devices with in-depth knowledge of their performance, allowing various scientific experiments, such as X-ray diffraction, computed controlled tomography, and ptychography.
A low noise 2.2 GHz PLL ASIC for the CSR external-target experiment
Authors: Hu Z. , Gao C. , Tian X. , Zhu P. , Liu J. , Wang H. , Chen K. , You B. , Xiao L. , Guo D. , Yang P. , Qiao Y. , Li Y. , Liu X. , Chen Q. , Sun X. , Huang G. , Liu F.
Published: February 2023

This paper presents the design and test results of a low noise Phase Locked Loop (PLL) Application Specific Integrated Circuit (ASIC), which is designed for the data transmission system in a pixel chip for a beam monitor of the Cooling Storage Ring (CSR) external target experiment at HIRFL in China. The proposed PLL consists of a differential ring oscillator, a digital divider, a three-state phase frequency detector, a current charge pump, a second-order loop filter and current mode level buffers. A prototype PLL ASIC has been fabricated in a standard 130 nm CMOS process. The test results show that the frequency of the output clock is about 2.2 GHz with a phase noise of −90 dBc/Hz at a frequency offset of 1 MHz and a root mean square jitter of 1.15 ps. The core circuit of the PLL consumes about 30 mW under the power supply of 1.2 V.
Fast transient infrared detection for time-domain astronomy
Authors: Drago A. , Pace E. , Bini S. , Guidi M.Cestelli , Cioeta F. , Marcelli A. , Bocci V.
Published: February 2023

Multi-messenger astronomy requires the use and development of telescopes and detectors for temporal observations across all the electromagnetic spectrum. The interest of our team is towards time-domain (or longitudinal, in the jargon of storage ring diagnostics) detectors able to make observations over the time rather than transversely by making photographs or spectrographs. The FAIRTEL (Fast InfraRed TELescope) experiment wants to build a very fast detector in the Mid InfraRed (MIR) to be used in time-domain astronomy. The experiment is oriented mainly toward the search of fast astronomical transients in the Galaxy, similarly to what has been observed in different electromagnetic ranges with the discovery of the FRBs (Fast Radio Burst) and the GRBs (Gamma-Ray Burst). In the last years, time-domain astronomy is growing in interest and intends to study events on time scales that can go from hundreds of milliseconds to microseconds and even shorter. The detector proposed by the FAIRTEL experiment, is based on HgCdTe semiconductors and on the experience done in the diagnostics for storage ring developed at DAFNE, the Italian e+/e− circular collider. The detection system design is in progress at the LNF (Laboratori Nazionali di Frascati) of INFN (Istituto Nazionale di Fisica Nucleare) while the telescope will be a standard reflecting type, like a Newtonian, a Cassegrain or a Ritchey–Chrétien telescope. The detection apparatus is under test at the IR synchrotron beamline SINBAD at DAFNE and it is foreseen to be implemented at the OPC (Osservatorio Polifunzionale del Chianti). It should be able to observe events with transients down to the nanosecond. A further development of the project involves the extension from ground-based observations to those by using balloons for scientific studies.
Assessment of an e-nose performance for the detection of COVID-19 specific biomarkers
Authors: Ghazaly Christelle , Biletska Krystyna , Thevenot Etienne A , Devillier Philippe , Naline Emmanuel , Grassin-Delyle Stanislas , Scorsone Emmanuel
Published: February 2023

Early, rapid and non-invasive diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is needed for the prevention and control of coronavirus disease 2019 (COVID-19). COVID-19 mainly affects the respiratory tract and lungs. Therefore, analysis of exhaled breath could be an alternative scalable method for reliable SARS-CoV-2 screening. In the current study, an experimental protocol using an electronic-nose (‘e-nose’) for attempting to identify a specific respiratory imprint in COVID-19 patients was optimized. Thus the analytical performances of the Cyranose®, a commercial e-nose device, were characterized under various controlled conditions. In addition, the effect of various experimental conditions on its sensor array response was assessed, including relative humidity, sampling time and flow rate, aiming to select the optimal parameters. A statistical data analysis was applied to e-nose sensor response using common statistical analysis algorithms in an attempt to demonstrate the possibility to detect the presence of low concentrations of spiked acetone and nonanal in the breath samples of a healthy volunteer. Cyranose® reveals a possible detection of low concentrations of these two compounds, in particular of 25 ppm nonanal, a possible marker of SARS-CoV-2 in the breath.
Eigenvalues and dynamical degrees of self-maps on abelian varieties
Authors: Hu Fei
Published: February 2023

Let

X
X

be a smooth projective variety over an algebraically closed field, and

f
:
X
→
X

f\colon X\to X

a surjective self-morphism of

X
X

. The

i
i

-th cohomological dynamical degree

χ
i

(
f
)

\chi _i(f)

is defined as the spectral radius of the pullback

f

∗

f^{*}

on the étale cohomology group

H

e

´

t

i

(
X
,

Q

ℓ

)

H^i_{\acute {\mathrm {e}}\mathrm {t}}(X, \mathbf {Q}_\ell )

and the

k
k

-th numerical dynamical degree

λ
k

(
f
)

\lambda _k(f)

as the spectral radius of the pullback

f

∗

f^{*}

on the vector space

N

k

(
X

)

R

\mathsf {N}^k(X)_{\mathbf {R}}

of real algebraic cycles of codimension

k
k

on

X
X

modulo numerical equivalence. Truong conjectured that

χ

2
k

(
f
)
=

λ
k

(
f
)

\chi _{2k}(f) = \lambda _k(f)

for all

0
≤
k
≤
dim
⁡
X

0 \le k \le \dim X

as a generalization of Weil’s Riemann hypothesis. We prove this conjecture in the case of abelian varieties. In the course of the proof we also obtain a new parity result on the eigenvalues of self-maps of abelian varieties in prime characteristic, which is of independent interest.
Updating the British Geriatrics Society recommended undergraduate curriculum in geriatric medicine: a curriculum mapping and nominal group technique study
Authors: Pearson Grace M E , Winter Rebecca , Blundell Adrian , Masud Tahir , Gough Joanna , Gordon Adam L ,   BGS Undergraduate Curriculum Nominal Group, Pound Susan , Thompson Sanja , Christopher Gary , Hart Dominic , Sanders Julie , Jennings Jo , Watson Alice , Miller-Molloy Felix , Miles Esther , Mohammed Biju , Wilkinson Iain , Al-Jawad Muna , Vassallo Michael , Henderson Emily J
Published: February 2023

Background

medical education must adapt to meet the challenges and demands of an ageing population, ensuring that graduates are equipped to look after older patients with complex health and social care needs. Recommended curricula in geriatric medicine in the United Kingdom and Europe offer guidance for optimal undergraduate education in ageing. The UK version, written by the British Geriatrics Society (BGS), requires updating to take account of innovations in the specialty, changing guidance from the General Medical Council (GMC), and the need to support medical schools preparing for the introduction of the national Medical Licensing Assessment (MLA).

Methods

the BGS recommended curriculum was mapped to the most recent European curriculum (2014) and the MLA content map, to compare and contrast between current recommendations and nationally mandated guidance. These maps were used to guide discussion through a virtual Nominal Group Technique (NGT), including 21 expert stakeholders, to agree consensus on the updated BGS curriculum.

Results

the curriculum has been re-structured into seven sections, each with 1–2 overarching learning outcomes (LOs) that are expanded in multiple sub-LOs. Crucially, the curriculum now reflects the updated GMC/MLA requirements, having incorporated items flagged as missing in the mapping stages.

Conclusion

the combined mapping exercise and NGT have enabled appropriate alignment and benchmarking of the UK national curriculum. These recommendations will help to standardise and enhance teaching and learning around the care of older persons with complexity.
Workplace Bullying in Pathology and Laboratory Medicine
Authors: Chiou Paul Z , Mulder Lotte , Jia Yuane
Published: February 2023

Objectives

The specific aims of the study are to explore the prevalence of workplace bullying and to understand the impact of bullying on individual wellness in order to facilitate the development of future organizational solutions to mitigate workplace incivility.

Methods

Cross-sectional data were collected via a web-based survey to gather exploratory demographic information and to assess the relationships between intensity of the exposure to the negative acts with laboratory productivity. Associations between laboratories offering resources to employees and their impacts on productivity and professional job fulfillment were also explored.

Results

Results of the survey showed that over two-thirds of laboratorians (68.56%) were classified as victims of workplace bullying, and the perpetrator is most likely a peer of the victim (55.3%). The study revealed the intensity of workplace incivility was positively correlated with the number of sick days taken by the laboratory practitioner (F(2, 217) = 24.245, P < .001). Facilities with a supportive work environment were also associated with a reduction in the number of sick mental days taken (P < .001), a proxy for improved work and health outcomes.

Conclusions

The results of this study shed light on the prevalence of incivility at the workplace and offer evidence on the importance of providing a supportive work environment toward reducing workplace bullying.
Chronic Lymphocytic Leukemia With Two B-Cell Populations of Discordant Light Chain Restrictions in Individual Patients: Parallel Development of Biclonal B-Cell Neoplasms or Clonal Evolution With Isotype Switch?
Authors: Zhao Yue , Siddiqi Imran , Wildes Tyler J , McCracken Jenna , Deak Kristen , Rehder Catherine , Wang Endi
Published: February 2023

Objectives

To evaluate clinicopathologic characteristics of biclonal chronic lymphocytic leukemia (CLL).

Methods

Retrospectively analyze clinical data and pathologic features.

Results

Ten cases were identified in which flow cytometry demonstrated an abnormal B-cell population with a CLL-like immunophenotype but showed no definitive light chain restriction. All had cytogenetic abnormalities detected, including seven with two CLL-related abnormalities. Four of these showed features suggestive of clonal evolution, all having del(13q) as a “stem-line” abnormality and three showing del(11q) as a “side-line” abnormality. Five (50%) cases demonstrated deleterious NOTCH1 mutations, in contrast to 11.8% in a control group of monoclonal CLL (P < .05). Of the 10 patients, 5 received treatment, with good/partial response in three cases and therapeutic resistance in one case. The median treatment-free survival was estimated at 68 months.

Conclusions

Despite a polytypic pattern of light chain expression, the neoplastic nature of biclonal CLL is suggested by a characteristic CLL phenotype and can be confirmed by cytogenetic and genomic analyses. The two clones with discordant light chain isotypes may share a “stem-line” cytogenetic abnormality, suggesting possible clonal evolution. Biclonal CLL is associated with NOTCH1 mutations, which may occur in a small subclone and gradually evolve in clonal size. Genomic analysis on light chain–sorted and/or chronologically collected samples may provide insight into clonal evolution in CLL.
Comparing DRD2 Promoter Methylation Between Blood and Brain in Alcohol Dependence
Authors: Arfmann Wiebke , Achenbach Johannes , Meyer-Bockenkamp Fiona , Proskynitopoulos Phileas J , Groh Adrian , Muschler Marc A N , Glahn Alexander , Hagemeier Lars , Preuss Vanessa , Klintschar Michael , Frieling Helge , Rhein Mathias
Published: February 2023

Aims

The dopamine receptor D2 (DRD2) is substantially involved in several forms of addiction. In addition to genetic polymorphisms, epigenetic mechanisms have emerged as an important means of regulation. Previously, DRD2 hypo- and hyper-methylation have been observed in alcohol use disorder (AUD). Blood samples are commonly used as a surrogate marker of epigenetic alterations in epigenetic research, but few specific comparisons between blood and brain tissue samples in AUD exist.

Methods

We used post-mortem brain tissue samples of 17 deceased patients with AUD and 31 deceased controls to investigate the relationship between blood and brain methylation of the DRD2 promoter.

Results

When investigating individual cytosine methylation sites (CpG), several significant differences were found in the nucleus accumbens and hippocampus in the study population. Investigating binding sites with significant differences in methylation levels revealed hypomethylated CpGs targeting mainly activating transcription factors.

Conclusion

These findings support an altered transcription of the DRD2 gene in AUD specimens with a consecutively changed reward response in the brain. While methylation between specific brain regions and blood is comparable, our study further suggests that blood methylation cannot provide meaningful perspectives on DRD2 promoter methylation in the brain.
Leaf optical properties and photosynthesis of fern species with a wide range of divergence time in relation to mesophyll anatomy
Authors: Hanba Yuko T , Nishida Keisuke , Tsutsui Yuuri , Matsumoto Mayu , Yasui Yutarou , Sizhe Yang , Matsuura Takumi , Kawaguchi Akitsu Tomoko , Kume Atsushi
Published: February 2023

Background and Aims

For a comprehensive understanding of the mechanisms of changing plant photosynthetic capacity during plant evolutionary history, knowledge of leaf gas exchange and optical properties are essential, both of which relate strongly to mesophyll anatomy. Although ferns are suitable for investigating the evolutionary history of photosynthetic capacity, comprehensive research of fern species has yet to be undertaken in this regard.

Methods

We investigated leaf optical properties, gas exchange and mesophyll anatomy of fern species with a wide range of divergence time, using 66 ferns from natural habitats and eight glasshouse-grown ferns. We used a spectroradiometer and an integrating sphere to measure light absorptance and reflectance by the leaves.

Key Results

The more newly divergent fern species had a thicker mesophyll, a larger surface area of chloroplasts facing the intercellular airspaces (Sc), thicker cell walls and large light absorptance. Although no trend with divergence time was obtained in leaf photosynthetic capacity on a leaf-area basis, when the traits were expressed on a mesophyll-thickness basis, trends in leaf photosynthetic capacity became apparent. On a mesophyll-thickness basis, the more newly divergent species had a low maximum photosynthesis rate, accompanied by a low Sc.

Conclusions

We found a strong link between light capture, mesophyll anatomy and photosynthesis rate in fern species for the first time. The thick mesophyll of the more newly divergent ferns does not necessarily relate to the high photosynthetic capacity on a leaf-area basis. Rather, the thick mesophyll accompanied by thick cell walls allowed the ferns to adapt to a wider range of environments through increasing leaf toughness, which would contribute to the diversification of fern species.
Cooperation of local features and global representations by a dual-branch network for transcription factor binding sites prediction
Authors: Yu Yutong , Ding Pengju , Gao Hongli , Liu Guozhu , Zhang Fa , Yu Bin
Published: February 2023

Interactions between DNA and transcription factors (TFs) play an essential role in understanding transcriptional regulation mechanisms and gene expression. Due to the large accumulation of training data and low expense, deep learning methods have shown huge potential in determining the specificity of TFs-DNA interactions. Convolutional network-based and self-attention network-based methods have been proposed for transcription factor binding sites (TFBSs) prediction. Convolutional operations are efficient to extract local features but easy to ignore global information, while self-attention mechanisms are expert in capturing long-distance dependencies but difficult to pay attention to local feature details. To discover comprehensive features for a given sequence as far as possible, we propose a Dual-branch model combining Self-Attention and Convolution, dubbed as DSAC, which fuses local features and global representations in an interactive way. In terms of features, convolution and self-attention contribute to feature extraction collaboratively, enhancing the representation learning. In terms of structure, a lightweight but efficient architecture of network is designed for the prediction, in particular, the dual-branch structure makes the convolution and the self-attention mechanism can be fully utilized to improve the predictive ability of our model. The experiment results on 165 ChIP-seq datasets show that DSAC obviously outperforms other five deep learning based methods and demonstrate that our model can effectively predict TFBSs based on sequence feature alone. The source code of DSAC is available at https://github.com/YuBinLab-QUST/DSAC/.
Glomerular diseases post-hematopoietic stem cell transplantation: pathologic spectrum and plausible mechanisms
Authors: Caza Tiffany N , Jhaveri Kenar D
Published: February 2023

Glomerular disease is an important complication in patients undergoing hematopoietic stem cell transplantation (HSCT), impacting approximately 1%–2% of all HSCT recipients and equating to 700–1400 cases per year worldwide. Development of kidney disease in HSCT recipients is often multifactorial and a kidney biopsy is required to identify the underlying disease etiology and pathology. While glomerular disease is an important toxicity following HSCT, there are few kidney biopsy studies examining this complication, with the majority being limited to small series and case reports. A range of glomerular diseases may occur in association with HSCT. The study by Yap et al. defines this disease spectrum, which includes (in descending order) thrombotic microangiopathy (38.7%), membranous nephropathy (25.8%), mesangial proliferative glomerulonephritis (12.9%), minimal change disease (9.7%), focal segmental glomerulosclerosis (9.7%) and membranoproliferative glomerulonephritis (3.2%). In this editorial, we summarize the study and prior studies looking at glomerular diseases associated with HSCT.
History of creatinine clearance: tribute to a forerunner
Authors: Losito Attilio
Published: February 2023

It is known to few that the path to the discovery of the long-denied plasma creatinine and its clearance was long and difficult. For quite a long time, related controversies between different groups of researchers were widespread and heated. The scientists who have dealt with the related problems are among the most famous of the last century and some of them are part of the history of medicine. Giovanni Ferro-Luzzi, an Italian clinician, was one of these researchers. He was among the first to detect and dose plasma creatinine and the first ever to measure the clearance of endogenous creatinine (CrCl). Unfortunately, due to a series of unforeseeable events, he has been completely forgotten together with his undertakings. In this review we retrace the steps that led to the measurement of plasma creatinine, and CrCl. With brief biographical notes we try to explain the oblivion of this important figure and of his nephrological accomplishments.
Between hunter and climate: the effects of hunting and environmental change on fecal glucocorticoid metabolite levels in two sympatric ungulate species in the Ruaha–Rungwa ecosystem, Tanzania
Authors: Hariohay Kwaslema Malle , Hunninck Louis , Ranke Peter S , Fyumagwa Robert D , Palme Rupert , Røskaft Eivin
Published: February 2023

Understanding the drivers of animal population decline is a key focus of conservation biologists. Anthropogenic activities such as hunting have long been established as potentially detrimental to a population’s persistence. However, environmental perturbations such as increased temperature variability, exacerbated by climate change, can also have important effects on animal populations. Animals can respond to these challenges by adjusting both their behavior and physiology. We measured fecal glucocorticoid metabolites (FGMs) of common impala (Aepyceros melampus) and greater kudu (Tragelaphus strepsiceros), both currently in stable populations, to examine effects of hunting, forage availability, daily variability in temperature and group size on their physiological stress response. The study was conducted across two adjacent protected areas, (i) one non-hunted area (Ruaha National Park; RNP) and (ii) one area used for trophy hunting (Rungwa Game Reserve; RGR). Both impala and kudu had significantly higher FGM levels in the area that allows hunting, while FGM levels decreased with increasing forage availability and increasing daily temperature. Moreover, impala (but not kudu) had lower FGM levels with larger group sizes. Our results indicate that the management regime can significantly alter the physiological state of wild ungulate populations. We also highlight the importance of considering the combined effects of anthropogenic, environmental and social contexts when studying the stress response of wild populations. Our results emphasize the value of protected areas and continued monitoring of hunting quota in order to maintain ungulate populations that are less vulnerable to population declines.
Using Trial and Observational Data to Assess Effectiveness: Trial Emulation, Transportability, Benchmarking, and Joint Analysis
Authors: Dahabreh Issa J , Matthews Anthony , Steingrimsson Jon A , Scharfstein Daniel O , Stuart Elizabeth A
Published: February 2023

Comparisons between randomized trial analyses and observational analyses that attempt to address similar research questions have generated many controversies in epidemiology and the social sciences. There has been little consensus on when such comparisons are reasonable, what their implications are for the validity of observational analyses, or whether trial and observational analyses can be integrated to address effectiveness questions. Here, we consider methods for using observational analyses to complement trial analyses when assessing treatment effectiveness. First, we review the framework for designing observational analyses that emulate target trials and present an evidence map of its recent applications. We then review approaches for estimating the average treatment effect in the target population underlying the emulation, using observational analyses of the emulation data alone and using transportability analyses to extend inferences from a trial to the target population. We explain how comparing treatment effect estimates from the emulation against those from the trial can provide evidence on whether observational analyses can be trusted to deliver valid estimates of effectiveness—a process we refer to as benchmarking—and, in some cases, allow the joint analysis of the trial and observational data. We illustrate different approaches using a simplified example of a pragmatic trial and its emulation in registry data. We conclude that synthesizing trial and observational data—in transportability, benchmarking, or joint analyses—can leverage their complementary strengths to enhance learning about comparative effectiveness, through a process combining quantitative methods and epidemiologic judgments.
Exercise-based cardiac rehabilitation for coronary heart disease: a meta-analysis
Authors: Dibben Grace O , Faulkner James , Oldridge Neil , Rees Karen , Thompson David R , Zwisler Ann-Dorthe , Taylor Rod S
Published: February 2023

Aims

Coronary heart disease is the most common reason for referral to exercise-based cardiac rehabilitation (CR) globally. However, the generalizability of previous meta-analyses of randomized controlled trials (RCTs) is questioned. Therefore, a contemporary updated meta-analysis was undertaken.

Methods and results

Database and trial registry searches were conducted to September 2020, seeking RCTs of exercise-based interventions with ≥6-month follow-up, compared with no-exercise control for adults with myocardial infarction, angina pectoris, or following coronary artery bypass graft, or percutaneous coronary intervention. The outcomes of mortality, recurrent clinical events, and health-related quality of life (HRQoL) were pooled using random-effects meta-analysis, and cost-effectiveness data were narratively synthesized. Meta-regression was used to examine effect modification. Study quality was assessed using the Cochrane risk of bias tool. A total of 85 RCTs involving 23 430 participants with a median 12-month follow-up were included. Overall, exercise-based CR was associated with significant risk reductions in cardiovascular mortality [risk ratio (RR): 0.74, 95% confidence interval (CI): 0.64–0.86, number needed to treat (NNT): 37], hospitalizations (RR: 0.77, 95% CI: 0.67–0.89, NNT: 37), and myocardial infarction (RR: 0.82, 95% CI: 0.70–0.96, NNT: 100). There was some evidence of significantly improved HRQoL with CR participation, and CR is cost-effective. There was no significant impact on overall mortality (RR: 0.96, 95% CI: 0.89–1.04), coronary artery bypass graft (RR: 0.96, 95% CI: 0.80–1.15), or percutaneous coronary intervention (RR: 0.84, 95% CI: 0.69–1.02). No significant difference in effects was found across different patient groups, CR delivery models, doses, follow-up, or risk of bias.

Conclusion

This review confirms that participation in exercise-based CR by patients with coronary heart disease receiving contemporary medical management reduces cardiovascular mortality, recurrent cardiac events, and hospitalizations and provides additional evidence supporting the improvement in HRQoL and the cost-effectiveness of CR.