bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient computations of continuous action densities of states for lattice models
Authors: Lucini Biagio , Francesconi Olmo , Holzmann Markus , Lancaster David , Rago Antonio
Published: March 2022

The Logarithmic Linear Relaxation (LLR) algorithm is an efficient method for computing densities of states for systems with a continuous spectrum. A key feature of this method is exponential error reduction, which allows us to evaluate the density of states of a system over hundreds of thousands of orders of magnitude with a fixed level of relative accuracy. As a consequence of exponential error reduction, the LLR method provides a robust alternative to traditional Monte Carlo calculations in cases in which states suppressed by the Boltzmann weight play nevertheless a relevant role, e.g., as transition regions between dominant configuration sets. After reviewing the algorithm, we will show an application in U(1) Lattice Gauge Theory that has enabled us to obtain the most accurate estimate of the critical coupling with modest computational resources, defeating exponential tunneling times between metastable vacua. As a further showcase, we will then present an application of the LLR method to the decorrelation of the topological charge in SU(3) Lattice Gauge Theory near the continuum limit. Finally, we will review in general applications of the LLR algorithm to systems affected by a strong sign problem and discuss the case of the Bose gas at finite chemical potential.
Formation of the diluted magnetic semiconductor phase by thermal diffusion in the pulsed laser deposition method
Authors: Kuznetsov Yu M , Dorokhin M V , Kriukov R N , Zdoroveyshchev A V , Zdoroveyshchev D A , Lesnikov V P
Published: March 2022

A new method for the formation of a diluted magnetic semiconductor based on gallium arsenide doped with iron and manganese atoms is considered. The method consists in diffusion doping during pulsed laser deposition in vacuum. Using the method of X-ray photoelectron spectroscopy, the profile of the chemical elements distribution was obtained. The magnetic phases influence on the behavior of the magnetic field dependence of the Hall resistance is analyzed. The technological parameters for the growth of the structure exhibiting ferromagnetic properties at room temperature were selected.
Determination of the phosphorus desorption rate during high-temperature annealing of the InP(001) substrate in an arsenic flux
Authors: Kolosovsky D A , Dmitriev D V , Ponomarev S A , Toropov A I , Zhuravlev K S
Published: March 2022

In this work, the process of phosphorus desorption from epi-ready InP(001) substrates during high-temperature annealing in an arsenic flux was experimentally investigated. An InPAs solid solution and InAs islands were formed on the surface upon annealing. The composition of the solid solution, the surface area fraction occupied by InAs islands, and its height depend on the annealing temperature. The phosphorus desorption rate was determined from the dependence of the arsenic atoms number on the substrate surface on the annealing temperature and the holding time in the arsenic flux. The phosphorus desorption rate increased from 6.03×1010 s−1⋅ cm−2 at an annealing temperature of 500 °C to 4.38×1011 s−1 ⋅ cm−2 at 540 °C. The activation energy of the phosphorus desorption process was 2.7 ± 0.2 eV.
Electron heating in GaN/AlGaN quantum well in a longitudinal electric field
Authors: Melentev G A , Kostromin N A , Vinnichenko M Ya , Firsov D A , Sarkisyan H A
Published: March 2022

The heating of electrons under longitudinal optical phonon scattering in a triangular GaN/AlGaN quantum well was studied theoretically. The energy loss rate of electrons was calculated in consideration of the dynamical screening and the hot phonon effect. The dependence of the electron temperature on the longitudinal electric field was calculated. The integral terahertz emission of hot two-dimensional electrons was simulated. The role of coupled plasmon-phonon mode scattering in the GaN/AlGaN quantum well was discussed.
Multiphoton microscopy of mesoporous silicon
Authors: Spivak Y M , Lemeshko P S
Published: March 2022

In this work, the behavior of the luminescence of mesoporous silicon under irradiation with a femtosecond IR laser is shown by the method of multiphoton microscopy. It was demonstrated that, along with the background photoluminescence of porous silicon, bright photoluminescence centers appear on the layer surface, and under certain conditions. Centers with a different, shorter-wavelength emission spectrum also appear.
A multi-wavelength approach to increase polarimeter diagnostic performance in nuclear fusion reactors
Authors: Wyss I. , Rossi R. , Gaudio P.
Published: March 2022

In future tokamaks, the huge variation of the plasma parameters during a discharge (ramp up, flat top, and ramp down) may involve that a diagnostic suitable for the flat top is not suitable for transients, and vice versa. Moreover, future reactors will start the experimental campaigns in safe scenarios, where events like disruptions are not critical, and they will increase their parameters gradually. Also in this case, a diagnostic optimised for the final target scenario may fail at the beginning of the experimental campaign. Laser-based polarimetry, a plasma diagnostic used in magnetized plasma to measure quantities that are related to the electron density, the magnetic field, and the electron temperature (in the case of relativistic effects), is a typical diagnostic that must be optimised for specific scenarios, since it is affected by several issues (refraction, type-I approximation, noise sensitivity) that limit its range of applicability. The aim of this work is to present a method to solve, or at least alleviate, this type of problem by using a multi-wavelength approach. The main idea consists of measuring the polarisation effects (Faraday rotation and Cotton-Mouton phase shift) with more than one wavelength and then calculating the plasma parameters by a weighted average of the measurements, where the weights are derived from the theory of polarimetry. The analysis is performed simulating the process of measurement introducing a casual error. The outcomes demonstrate that the adoption of a multi-wavelength polarimeter system brings a more accurate measurement in a wider range. Considering that next tokamaks will be implemented with a dual-wavelength interferometer, like the dispersion interferometer-polarimeter of ITER, this proposed approach could be taken into consideration to increase the performances of polarimetry.
Hybridized and Complementary Comparative Analysis of Dissolved Gases in a Power Transformer
Authors: Kaur Kulraj , Bhalla Deepika , Singh Jashandeep
Published: March 2022

Power transformer is considered important equipment both in the transmission and distribution zone of electric power. Safety of power system elements plays a crucial role for enhancing its reliability. Transformer being a major component plays a much vital role and needs to be monitored and maintained at a regular basis. Transformer oil helps in performing the functions of insulation, cooling and helps extinguish arcs. Transformer oil also dissolves the gases which get generated by the degradation of oil, presence of moisture and gas from insulation deterioration of cellulose, gases and moisture from the surrounding, to which the oil is exposed. The dissolved gas present in an oil sample can be helpful in determining the nature of a fault which can vary according to gas types and its concentrations. DGA (Dissolved Gas Analysis) have been used as a suitable tool in enabling the reliability of the system and safety of the transformer for a long time. An analysis of Dissolved gases in oil is analytical method and have been used and interpreted differently by different methods and users. DGA methods using ratios, gas concentration and graphical methods have been presented in this work. The tools use mix of fuzzy based analysis, MATLAB. The basic motivation of the work is to create a platform for DGA analysis so as to provide early and easy detection and diagnosis of Transformer Failures.
Effects of stacking sequences and longitudinal parameter on the dynamic characteristics of multilayer glass epoxy composite
Authors: Desai Saumil , Mehta Vishal
Published: March 2022

In the current scenario, the structures made of composites are drawing attention due to their high spring rate, capacity to withstand high force, reinforcement and optimized mass. Up till now, several materials have been designed and manufactured. The components as well as structures made of these composite materials do expose to dynamic loading during their functions which leads to the failure of the respective component/structure. The dynamic characteristics depend on the material properties, physical dimension, no. of layers, orientation of the fibers and end conditions. Here an analysis is performed to determine the vibration characteristics of multilayer composite beams made of glass epoxy composite. The Cantilever boundary condition is considered. Ten layers are considered. Various stacking are considered with the different fiber orientations. The natural frequency of a multilayer composite beam is sensitive to the length and fiber orientations. As the length and number of layer increase, the natural frequency decreases. The natural frequency for fiber orientation at 900is minimum as compared to other fiber orientations irrespective of the length while the natural frequencies for the 00fiber orientation is more compared to other orientations for out of plane vibrations irrespective of the geometrical dimensions. The natural frequencies for other orientations are more compared to 00orientation for specific modes due to high stiffness in the torsional direction.
Modelling and Analysis of Magnesium-Fiber Composite Material for Aircraft Applications
Authors: Chauhan Nathi Ram , Khera Arhantika , Agarwal Shubhi , Bagri Mehak , Aggarwal Aditi
Published: March 2022

Weight to strength ratio of materials used in the aerospace industry is one of their most important characteristics. Thus, the low density of Magnesium alloys is making them surge as the most sought-after material in the field of aeronautics. Actually, the density of Magnesium alloys is only two third than that of Aluminium alloys. This asset creates an enormous opportunity in making aircraft structures of less weight. In addition to this, good machinability and castability is displayed by Magnesium alloys. Fiber Metal Laminates (FML), which are bound together through epoxy, are being used extensively inside the aircraft enterprise. In this illustration, two varieties of FML (fiber material between 2 layers of magnesium alloys of 2 mm thickness each) are studied. FML-1, which has carbon fiber sandwiched between magnesium alloy, and FML-2 which has Jute fiber sandwiched between magnesium alloy layers. The laminates are then analyzed in the software ANSYS for tensile and bending load systems. The FMLs are compared to basic model of Magnesium alloy having 6 mm thickness and the results are compared for three parameters: Total Deformation, Eq von mises strain, and Eq von mises stress. The investigation concluded that carbon FML performs best under Tensile load system, while FML made of jute fiber is best suited under Bending load system.
Topological and Reliable based selection of Inverter module for PV application under standard parameters of Cost and life-Span
Authors: Sharma Shivam , Kaur Gagandeep , Sharma Naveen K.
Published: March 2022

With the advancement in manufacturing and fabrication process, utilization of PV energy systems is increased throughout the globe which leads to the increase of research over lifespan and reliability index on an entire PV system. This increment results in low average manufacturing as well running costs of the entire PV system. The most important portion of the PV system apart from the PV module is the inverter unit which provides conversion and synchronization between the PV system and OLGS. With vast research carried over design as well controlling the architecture of Inverter, it becomes a tedious task to choose the optimal design based on the application area and capital cost. In this paper, we discuss issues faced by the inverter units on the platform of reliability and life span along with the suitable survey. Further to conclude the work result of Inverter unit connected to selected PV module when connected to OLGS.
Multidisciplinary avenues on the integration of industry 4.0 in the degree of mechanical engineering
Authors: Deshpande Mayank , Khandelwal Mayank , Singh Kunal
Published: March 2022

The world is moving towards Industry 4.0. There has been rapid growth in a different type of technologies being used in industries. Modern industries have been exploiting the digitalization of machines to increase efficiency and analyzing the data for various other purposes. Even though mechanical engineers and manufacturing move hand in hand, in this data-driven production era, mechanical engineers will have to adapt themselves to various other technologies from automation to data analytics for their efficient implementation. This paper proposes a conceptual framework for Industry 4.0, and also discusses how these technological advancements will assist mechanical engineers in various tasks like designing, machining, etc. The suggested framework covers the entire lifecycle from manufacturing to product deployment in the sense of Industry 4.0.
Smart Techniques for Fault Diagnosis in Power Transformer
Authors: Sharma Naveen Kumar , Bhalla Deepika , Manisha  , Kaur Kulraj
Published: March 2022

In a power network installed transformers are among the most expensive equipment. Outage of a transformer causes substantial financial loss not only due to the cost involved in repair or replacement, but also due to loss of revenue until corrective action is taken. To avoid the financial and reliability loss in the past two decades the monitoring of in-service transformer health has become obligatory for the utilities. The tests that were earlier done were to assess the dame of permanent nature. However, it has been known for quite some time that system abnormalities, switching. Loading, ambient conditions contribute to accelerated aging that results in sudden failure or incipient faults. Monitoring the condition of in-service equipment can always reduce failure risk. For early detection of fault dissolved gas analysis, furan analysis and degree of polymerization are the recent techniques that are becoming prevalent. A real-time assessment of the transformer condition using these techniques is an important tool for enhancing system reliability.
Symmetry-protected bound states in the continuum in graphene nanoribbons
Authors: Wang Weihua , You Bin
Published: March 2022

Bound states in the continuum (BICs) have emerged as a significant design principle for producing systems with high-quality (Q) factor states to enhance light–matter interactions. As a particular case, symmetry-protected BICs are flexible to be designed, commonly by utilizing two identical lossless dielectric elements. Herein, different from previous studies, we propose symmetry-protected BICs in a plasmonic structure of two contacting graphene nanoribbons (GNRs), in which two GNRs are not identical and lossy. We show that BICs are achieved when two GNRs are perpendicular to each other, and as the vertical GNR deviates from the vertical direction (inversion symmetry breaking), it will evolve into quasi-BICs, with a new resonance dip appearing in the transmission spectrum. The spectrum curve can be well described by the coupled-mode theory, from which the variation of two fundamental states is clearly seen. Since in the presence of internal loss, the Q-factor of quasi-BICs does not follow the linear formula that is generally valid for symmetry-protected BICs. Alternatively, an extended formula is derived, which predicts exactly the behavior of the Q-factor of quasi-BICs. Besides BICs, the structure can also support plasmonically induced transparency (PIT) like effects, through rotating the vertical GNR to a particular angle. Therefore, a mechanically tunable switch, from BIC to PIT, is achieved here. Our work demonstrates an alternative scheme for BICs, and a new degree of freedom for tuning plasmonic coupling related effects.
Development of the PhysioVessel: a customizable platform for simulating physiological fluid resuscitation
Authors: Berard David , Vega Saul J , Torres Sofia I Hernandez , Polykratis I Amy , Salinas Jose , Ross Evan , Avital Guy , Boice Emily N , Snider Eric J
Published: March 2022

Uncontrolled hemorrhage is a leading cause of death in trauma situations. Developing solutions to automate hemorrhagic shock resuscitation may improve the outcomes for trauma patients. However, testing and development of automated solutions to address critical care interventions, oftentimes require extensive large animal studies for even initial troubleshooting. The use of accurate laboratory or in-silico models may provide a way to reduce the need for large animal datasets. Here, a tabletop model, for use in the development of fluid resuscitation with physiologically relevant pressure-volume responsiveness for high throughput testing, is presented. The design approach shown can be applied to any pressure-volume dataset through a process of curve-fitting, 3D modeling, and fabrication of a fluid reservoir shaped to the precise curve fit. Two case studies are presented here based on different resuscitation fluids: whole blood and crystalloid resuscitation. Both scenarios were derived from data acquired during porcine hemorrhage studies, used a pressure-volume curve to design and fabricate a 3D model, and evaluated to show that the test platform mimics the physiological data. The vessels produced based on data collected from pigs infused with whole blood and crystalloid were able to reproduce normalized pressure-volume curves within one standard deviation of the porcine data with mean residual differences of 0.018 and 0.016, respectively. This design process is useful for developing closed-loop algorithms for resuscitation and can simplify initial testing of technologies for this life-saving medical intervention.
Changes in US background ozone associated with the 2011 turnaround in Chinese NOx emissions
Authors: Miyazaki Kazuyuki , Neu Jessica L , Osterman Greg , Bowman Kevin
Published: March 2022

Assessing the effectiveness of surface ozone air quality regulations is complicated by non-local sources and inhibited by sparse in situ observational networks. Here, we harness satellite measurements of ozone and its precursors over Asia to identify the Asian contribution to background ozone over the United States (US) from 2006-2016 using a state-of-the-art chemical data assimilation system. Our results indicate that Chinese NOx emissions reached an apex in 2011, increasing daily average ozone concentrations over Los Angeles by up to 3.8 ppb at 750 hPa and 0.7 ppb at the surface in 2012 relative to 2006, with somewhat larger impacts in the high altitude regions of the Western US (assuming constant VOC emissions). Decreasing Chinese NOx emissions after 2011 contributed to a reduction of similar magnitude in Western US background ozone from 2012-2016. We also assess the impact of direct assimilation of satellite-based tropospheric ozone profile measurements over Asia and find that it substantially modifies global ozone, including US surface concentrations. These results suggest that measurements of both ozone and its precursors over Asia play a substantial role in evaluating not only local but also global air quality. The simultaneous assimilation of ozone and its precursors proffers a powerful way to constrain the vertical profile of ozone and improve understanding of ozone variations. In the future, a more extensive satellite observing system has great potential to better constrain both local pollution and background ozone globally when employed in conjunction with chemical data assimilation.
Reduced recombination through CZTS/CdS interface engineering in monograin layer solar cells
Authors: Kauk-Kuusik M , Timmo K , Muska K , Pilvet M , Krustok J , Danilson M , Mikli V , Josepson R , Grossberg-Kuusk M
Published: March 2022

The power conversion efficiency of Cu2ZnSnS4 (CZTS) solar cells is still limited by deep defects, low minority carrier lifetime and high recombination rates at the CZTS/CdS interface. The objective of this study was to find an effective method to reduce interface recombination of CZTS monograin layer solar cells. A two-step heterojunction formation process was applied by controlling the intermixing of Cd and Cu in the CZTS/CdS interface, which resulted in improved device efficiency of up to 11.7%. Surface analysis by x-ray photoelectron spectroscopy confirmed Cd diffusion into the surface of CZTS after CdS air-annealing by forming an ultra-thin Cu2Zn
x
Cd1−x
SnS4 layer. Moreover, external quantum efficiency measurements showed that the absorption edge shifts to longer wavelengths with the addition of Cd into the CZTS surface layer. This surface modification and replacement of a CdS:Cu buffer layer by fresh CdS greatly reduced the interface recombination and improved the junction quality, contributing to an enhancement of J
SC ∼3 mA cm−2 (from 20.5 to 23.6 mA cm−2) and fill factor ∼14% (from 59.4% to 67.7%). The serial resistance of the CZTS monograin layer solar cells was significantly reduced from 2.4 Ω cm2 to 0.67 Ω cm2. To understand the electrical behavior of the highest-efficiency CZTS monograin layer solar cell in more detail, the temperature-dependent current–voltage characteristics were analyzed.
Brownian regularity for the Airy line ensemble, and multi-polymer watermelons in Brownian last passage percolation
Authors: Hammond Alan
Published: March 2022

The Airy line ensemble is a positive-integer indexed system of random continuous curves whose finite dimensional distributions are given by the multi-line Airy process. It is a natural object in the KPZ universality class: for example, its highest curve, the Airy

2

_2

process, describes after the subtraction of a parabola the limiting law of the scaled energy of a geodesic running from the origin to a variable point on an anti-diagonal line in such problems as Poissonian last passage percolation. The ensemble of curves resulting from the Airy line ensemble after the subtraction of the same parabola enjoys a simple and explicit spatial Markov property, the Brownian Gibbs property.

In this paper, we employ the Brownian Gibbs property to make a close comparison between the Airy line ensemble’s curves after affine shift and Brownian bridge, proving the finiteness of a superpolynomially growing moment bound on Radon-Nikodym derivatives.

We also determine the value of a natural exponent describing in Brownian last passage percolation the decay in probability for the existence of several near geodesics that are disjoint except for their common endpoints, where the notion of ‘near’ refers to a small deficit in scaled geodesic energy, with the parameter specifying this nearness tending to zero.

To prove both results, we introduce a technique that may be useful elsewhere for finding upper bounds on probabilities of events concerning random systems of curves enjoying the Brownian Gibbs property.

Several results in this article play a fundamental role in a further study of Brownian last passage percolation in three companion papers (Hammond 2017a,b,c), in which geodesic coalescence and geodesic energy profiles are investigated in scaled coordinates.
Doing and allowing good
Authors: Unruh Charlotte Franziska
Published: March 2022

Many people think that the moral reason against doing harm is stronger than the moral reason against allowing harm. What should these people think about doing and allowing good? I address this question by distinguishing two ways of understanding the doing/allowing distinction. The agency view implies that the moral reason for doing good is stronger than the moral reason for allowing good. The imposition view implies that the moral reason against preventing good is stronger than the moral reason against failing to do good. I defend the imposition view and explore its implications for the comparative strength of harm-based and benefit-based reasons.
Evaluating performance of existing computational models in predicting CD8+ T cell pathogenic epitopes and cancer neoantigens
Authors: Buckley Paul R , Lee Chloe H , Ma Ruichong , Woodhouse Isaac , Woo Jeongmin , Tsvetkov Vasily O , Shcherbinin Dmitrii S , Antanaviciute Agne , Shughay Mikhail , Rei Margarida , Simmons Alison , Koohy Hashem
Published: March 2022

T cell recognition of a cognate peptide–major histocompatibility complex (pMHC) presented on the surface of infected or malignant cells is of the utmost importance for mediating robust and long-term immune responses. Accurate predictions of cognate pMHC targets for T cell receptors would greatly facilitate identification of vaccine targets for both pathogenic diseases and personalized cancer immunotherapies. Predicting immunogenic peptides therefore has been at the center of intensive research for the past decades but has proven challenging. Although numerous models have been proposed, performance of these models has not been systematically evaluated and their success rate in predicting epitopes in the context of human pathology has not been measured and compared. In this study, we evaluated the performance of several publicly available models, in identifying immunogenic CD8+ T cell targets in the context of pathogens and cancers. We found that for predicting immunogenic peptides from an emerging virus such as severe acute respiratory syndrome coronavirus 2, none of the models perform substantially better than random or offer considerable improvement beyond HLA ligand prediction. We also observed suboptimal performance for predicting cancer neoantigens. Through investigation of potential factors associated with ill performance of models, we highlight several data- and model-associated issues. In particular, we observed that cross-HLA variation in the distribution of immunogenic and non-immunogenic peptides in the training data of the models seems to substantially confound the predictions. We additionally compared key parameters associated with immunogenicity between pathogenic peptides and cancer neoantigens and observed evidence for differences in the thresholds of binding affinity and stability, which suggested the need to modulate different features in identifying immunogenic pathogen versus cancer peptides. Overall, we demonstrate that accurate and reliable predictions of immunogenic CD8+ T cell targets remain unsolved; thus, we hope our work will guide users and model developers regarding potential pitfalls and unsettled questions in existing immunogenicity predictors.
Role of yoga in managing the consequences of work stress—a review
Authors: K. N. Harini , Nilkantham Savithri
Published: March 2022

The purpose of this study is to systematically review the literature on the role of yoga in managing the consequences of work stress to examine the current body of knowledge in this field and to provide directions for future research in this domain. A comprehensive literature search of 14 databases using 12 different search term combinations in the area of ‘yoga and work stress’ was carried out till the period January 2022 following the PRISMA guidelines to select the relevant English-language peer-reviewed SCImago Ranked articles for review. Two broad classification areas were considered to understand the research question of interest in this study: (i) consequences of work stress [which includes—(a) behavioural; (b) physical; and (c) psychological] and; (ii) schools of thought in yoga for work stress management [which includes—(a) Hatha yoga (HY); (b) Vini yoga (VY); (c) Dru yoga (DY); (d) Integrated yoga (IY); (e) Kundalini yoga (KUY); (f) Kripalu yoga (KRY); (g) Iyengar yoga; (h) Ashtanga yoga (AY); (i) Power yoga (PY); and (j) Yoga (General)]. The main contribution of this study is that it is the first of its kind comprehensive review in the area of ‘yoga and its role in managing the consequences of work stress’ collating the dispersed knowledge in this area by indicating the various understudied stand-alone and combined consequences of work stress and the less researched schools of thought in yoga and yoga practices administered to manage these consequences of work stress, to provide promising avenues for further examination for the development of this research field.
We have reached a dead end for preimplantation genetic testing for aneuploidy
Authors: Gleicher Norbert , Barad David H , Patrizio Pasquale , Orvieto Raoul
Published: March 2022

The hypothesis of preimplantation genetic testing for aneuploidy (PGT-A) was first proposed 20 years ago, suggesting that during IVF elimination of aneuploid embryos prior to transfer will improve implantation rates of remaining embryos and, therefore, increase pregnancy and live birth rates, while also reducing miscarriages. Subsequently, unvalidated and increasingly unrestricted clinical utilization of PGT-A called for at least one properly randomized controlled trial (RCT) to assess cumulative live birth rates following a single oocyte retrieval, utilizing all fresh and frozen embryos of an IVF cycle. Only recently two such RCTs were published, however both, when properly analysed, not only failed to demonstrate significant advantages from utilization of PGT-A, but actually demonstrated outcome deficits in comparison to non-use of PGT-A, when patient selection biases in favour of PGT-A were reversed. Moreover, because of high embryo mosaicism at the blastocyst stage and, therefore, high false-positive rates from trophectoderm biopsies, large numbers of chromosomal-normal embryos with normal pregnancy potential are unnecessarily left unused or discarded, indisputably causing harm to affected couples. We, therefore, strongly call for restricting PGT-A to only research protocols and, as of this point in time, encourage professional societies in the field to follow suit with appropriate practice guidelines.
The Viability of Hematopoietic Progenitor Cell Grafts after Cryopreservation Does Not Predict Delayed Engraftment in Allogeneic Hematopoietic Stem Cell Transplantation
Authors: Fadeyi Emmanuel , Mamo Yafet T , Saha Amit K , Wilson Emily , Pomper Gregory
Published: March 2022

Objective

Due to the COVID-19 pandemic, more peripheral blood stem cell (PBSC) allogeneic grafts are being frozen and infused thawed. Our objective was to study the influence of graft viability on engraftment outcome in patients treated with PBSCs.

Methods

Using trypan blue stain, we compared total nucleated cell (TNC) viability of both fresh and thawed grafts in allogeneic PBSCs.

Results

The viability of thawed PBSC grafts median was 74%, and fresh was 99.0%. The median number of CD34 + cells/kg infused thawed was 6.3 × 106/kg and median time to neutrophil and platelet engraftment was 17.5 and 20 days. Median number of CD34 + cells/kg infused fresh was 5.1 × 106/kg and median time to neutrophil and platelet engraftment was 18 and 19 days. There were no statistically significant differences in the time to engraftment between the 2 groups.

Conclusion

A low TNC viability of thawed PBSC grafts does not have an effect on time to neutrophil and platelet engraftment when more than 2.85 × 106 CD34 + cells/kg are infused.
Game equivalence and expressive power of game description languages: a bisimulation approach
Authors: Jiang Guifei , Perrussel Laurent , Zhang Dongmo , Zhang Heng , Zhang Yuzhi
Published: March 2022

Bisimulations are a key notion to study the expressive power of a modal language. This paper studies the expressivity of Game Description Language (GDL) and its epistemic extension Epistemic GDL (EGDL) through a bisimulation approach. We first define a notion of bisimulation for GDL and prove that it coincides with the indistinguishability of GDL formulas. Based on it, we establish a characterization of the definability of GDL in terms of $k$-bisimulations. Then we design novel notions of bisimulation for EGDL and obtain characterizations of the expressive power of EGDL in terms of them. These characterizations provide a powerful tool to identify the expressive power of game description languages. Finally, we demonstrate with real games that bisimulation can be generalized to capture a wide range of game equivalence.
New evidence for a cosmological distribution of stellar mass primordial black holes
Authors: Hawkins M R S
Published: March 2022

In this paper, we show that to explain the observed distribution of amplitudes in a large sample of quasar light curves, a significant contribution from microlensing is required. This implies the existence of a cosmologically distributed population of stellar mass compact bodies making up a large fraction of the dark matter. Our analysis is based on the light curves of a sample of over 1000 quasars, photometrically monitored over a period of 26 yr. The intrinsic variations in quasar luminosity are derived from luminous quasars where the quasar accretion disc is too large to be microlensed by stellar mass bodies, and then synthetic light curves for the whole sample are constructed with the same statistical properties. We then run microlensing simulations for each quasar with convergence in compact bodies appropriate to the quasar redshift assuming a Lambda cold dark matter cosmology. The synthetic light curve is then superimposed on the amplification pattern to incorporate the effects of microlensing. The distribution of the resulting amplitudes can then be compared with observation, giving a very close match. This procedure does not involve optimizing parameters or fitting to the data, as all inputs such as lens mass and quasar disc size come from independent observations in the literature. The overall conclusion of the paper is that to account for the distribution of quasar light curve amplitudes it is necessary to include the microlensing effects of a cosmologically distributed population of stellar mass compact bodies, most plausibly identified as stellar mass primordial black holes.
Madness
Authors: Garson Justin
Published: March 2022

Since the time of Hippocrates, madness has typically been viewed through the lens of disease, dysfunction, and defect. Madness, like all other disease, happens when something in the mind or brain does not operate the way that it should, or as nature intended. In this paradigm, the role of the healer is simply to find the dysfunction and fix it. This remains the dominant perspective in global psychiatry today. This book presents a different paradigm for conceiving of madness and the forms that it takes. In this paradigm, madness-as-strategy, madness is neither a disease nor a defect, but a designed feature, like the heart or lungs. That is to say, at least sometimes, when someone is mad, everything inside of them is working exactly as it ought and as nature intended. Through engagement with texts spanning from the classical era to Darwinian medicine, Madness: A Philosophical Exploration shows that madness-as-strategy is not a new conception. Thus, more than a history of science or a conceptual genealogy, Madness: A Philosophical Exploration is a recovery mission. In recovering madness-as-strategy, it leads us beyond today’s dominant medical paradigm toward a very different form of thinking and practice. It also draws out the implication of the madness-as-strategy paradigm for philosophers of medicine and psychiatry, historians and sociologists of medicine, and mental health service users, survivors, and activists. It outlines a new conception of mental disorder, it provides a novel reading of the history of madness, and it presents an alternative vision of what it means to be mad.
Postoperative C5 Palsy Following Cervical Laminectomy With Instrumented Fusion Versus Cervical Laminoplasty With Reconstruction
Authors: Kim Jinseong , Shankar Dhruv S. , Bienstock Dennis M. , Gao Michael , Lee Yunsoo , Chaudhary Saad B. , Bronson Wesley H. , Hecht Andrew C.
Published: March 2022

Study Design:

This was a retrospective cohort study.

Objective:

The objective of this study was to investigate whether cervical laminectomy with instrumented fusion (LF) and cervical laminoplasty with reconstruction (LP) are associated with different rates C5 palsy (C5P) at 1-month follow-up in a single surgeon and nationally representative cohort.

Summary of Background Data:

LF and LP both carry a well-known risk of nerve root injury that most commonly presents as C5P which can reduce patient satisfaction, patient function, and impede patient recovery. The procedure type that is more frequently associated with C5P remains largely unclear.

Methods:

We identified patients undergoing primary LF or LP procedures for the treatment of cervical myelopathy in both a single-surgeon series cohort (2004–2018; Mount Sinai Hospital) and a nationally representative cohort drawn from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database (2006–2017). For the single-surgeon cohort, C5P within 1 month of surgery was recorded. For the NSQIP cohort, peripheral nerve injury (PNI) within 1 month of surgery was recorded and used as a proxy for C5P. Postoperative complications including C5P were compared between cohorts. Multivariable logistic regression was used to evaluate the association between procedure type and postoperative C5P or PNI.

Results:

Without adjusting for covariates, LF patients had a higher rate of 1-month C5P in the single-surgeon cohort (8% vs. 0%, P=0.01). An adjusted odds ratio could not be obtained due to the absence of C5P in the LP group. In the national cohort, LP patients had a significantly higher rate of 1-month PNI on unadjusted analysis (11% vs. 16%, P<0.001). After adjusting for covariates, we found no significant difference in odds of 1-month PNI between LF and LP (adjusted odds ratio=0.84, P=0.07).

Conclusions:

Overall, the single-surgeon series suggest that cervical LF is associated with significantly higher rates of postoperative C5P as compared with LP. These findings are not corroborated by nationally representative data, which showed no difference in PNI rates between LF and LP. A surgeon’s training and experience likely contribute to which procedure has a higher propensity for a C5P as a complication. Regardless, both LF and LP patients should be closely monitored for new-onset C5P during follow-up visits.

Level of Evidence:

Level III.
Cervical Total Disk Replacement
Authors: Guyer Richard D. , Coric Domagoj , Nunley Pierce D. , Ohnmeiss Donna D.
Published: March 2022

Study Design:

This study was a post hoc analysis of data collected from 2 Food and Drug Administration (FDA) Investigational Device Exemption (IDE) trials.

Objective:

The purposes of this study were to: (1) measure disk space heights adjacent to the level to be treated with a total disk replacement (TDR); (2) analyze cervical disk space heights to be replaced with TDR; and (3) investigate the frequency of use of a smaller height TDR when available.

Summary of Background Data:

Cervical TDR produces outcomes noninferior or superior to anterior cervical discectomy and fusion. While the restoration of the height of a collapsed, degenerated disk is a surgical goal, there are potential problems with overdistracting the segment with an implant.

Methods:

Disk heights were measured using radiographs from the 1-level Simplify Cervical Artificial Disk IDE trial, producing values for 259 levels adjacent to the treated level and 162 treated levels. The device is available in 4, 5, and 6 mm heights. The 4 mm height became available only after treatment was 13% complete in the single-level trial and was available for all of the 2-level trial.

Results:

Measurements of 259 adjacent levels found that 55.2% of disk spaces had a height of <4 mm. Among operated levels, 82.7% were <4 mm. When a 4 mm TDR was available, it was used in 38.4% of operated levels in the 1-level trial and 54.3% of levels in the 2-level trial.

Conclusions:

Among nonoperated levels, 55.2% were of height <4 mm, suggesting that TDRs of greater heights may potentially overdistract the disk space. The 4 mm TDR was selected by surgeons in 49.4% of all implanted levels, suggesting a preference for smaller TDR height. Further investigation is warranted to determine if the lower height implants are related to clinical and/or radiographic outcomes.

Level of Evidence:

Level III.
After 9,000 laparotomies for blunt trauma, resuscitation is becoming more balanced and time to intervention shorter: Evidence in action
Authors: Douglas Molly , Obaid Omar , Castanon Lourdes , Reina Raul , Ditillo Michael , Nelson Adam , Bible Letitia , Anand Tanya , Gries Lynn , Joseph Bellal
Published: March 2022

BACKGROUND

Several advancements in hemorrhage control have been advocated for in the past decade, including balanced transfusions and earlier times to intervention. The aim of this study was to examine the effect of these advancements on outcomes of blunt trauma patients undergoing emergency laparotomy.

METHODS

This is a 5-year (2013–2017) analysis of the Trauma Quality Improvement Program. Adult (18 years or older) blunt trauma patients with early (≤4 hours) packed red blood cell (PRBC) and fresh frozen plasma (FFP) transfusions and an emergency (≤4 hours) laparotomy for hemorrhage control were identified. Time-trend analysis of 24-hour mortality, PRBC/FFP ratio, and time to laparotomy was performed over the study period. The association between mortality and PRBC/FFP ratio, patient demographics, injury characteristics, transfusion volumes, and American College of Surgeons verification level was examined by hierarchical regression analysis adjusting for interyear variability.

RESULTS

A total of 9,773 blunt trauma patients with emergency laparotomy were identified. The mean ± SD age was 44 ± 18 years, 67.5% were male, and median Injury Severity Score was 34 (range, 24–43). The mean ± SD systolic blood pressure at presentation was 73 ± 28 mm Hg, and the median transfusion requirements were PRBC 9 (range, 5–17) and FFP 6 (range, 3–12). During the 5-year analysis, time to laparotomy decreased from 1.87 hours to 1.37 hours (p < 0.001), PRBC/FFP ratio at 4 hours decreased from 1.93 to 1.71 (p < 0.001), and 24-hour mortality decreased from 23.0% to 19.3% (p = 0.014). On multivariate analysis, decreased PRBC/FFP ratio was independently associated with decreased 24-hour mortality (odds ratio, 0.88; p < 0.001) and in-hospital mortality (odds ratio, 0.89; p < 0.001).

CONCLUSION

Resuscitation is becoming more balanced and time to emergency laparotomy shorter in blunt trauma patients, with a significant improvement in mortality. Future efforts should be directed toward incorporating transfusion practices and timely surgical interventions as markers of trauma center quality.

LEVEL OF EVIDENCE

Therapeutic/care management, level III.
A disturbing trend: An analysis of the decline in surgical critical care fellowship training of Black and Hispanic surgeons
Authors: Hambrecht Amanda , Berry Cherisse , DiMaggio Charles , Chiu William , Inaba Kenji , Frangos Spiros , Krowsoski Leandra , Ricketts Greene Wendy , Issa Nabil , Pugh Carla , Bukur Marko
Published: March 2022

BACKGROUND

Underrepresented minorities in medicine (URiMs) are disproportionally represented in surgery training programs. Rates of URiMs applying to and completing General Surgery residency remain low. We hypothesized that the patterns of URiMs disparities would persist into surgical critical care (SCC) fellowship applicants, matriculants, and graduates.

METHODS

We performed a retrospective analysis of SCC applicants, matriculants, and graduates from 2005 to 2020 using the graduate medical education resident survey and analyzed applicant characteristics using the Surgical Critical Care and Acute Care Surgery Fellowship Application Service from 2018 to 2020. The data were stratified by race/ethnicity and sex. Indicator variables were created for Asian, Hispanic, White, and Black trainees. Yearly proportions for each race/ethnicity and sex categories completing or enrolling in a program were calculated and plotted over time with Loess smoothing lines and overlying 95% confidence bands. The yearly rate and statistical significance of change over time were tested with linear regression models with race/ethnicity and sex proportion as the dependent variables and year as the explanatory variable.

RESULTS

From 2005 to 2020, there were a total of 2,481 graduates. Black men accounted for 4.7% of male graduates with a significant decline of 0.3% per year for the study period of those completing the fellowship (p = 0.02). Black women comprised 6.4% of female graduates and had a 0.6% decline each year (p < 0.01). A similar trend was seen with Hispanic men, who comprised 3.2% of male graduates and had a 0.3% annual decline (p = 0.02). White men had a significant increase in both matriculation to and graduation from SCC fellowships during the same interval. Similarly, Black and Hispanic applicants declined from 2019 to 2020, while the percentage of White applicants increased.

CONCLUSION

Disparities in URiMs representation remain omnipresent in surgery and extend from residency training to SCC fellowship. Efforts to enhance the recruitment and retention of URiMs in SCC training are warranted.

LEVEL OF EVIDENCE

Prognostic and Epidemiologic; level IV.
Healthcare Professionals’ Understandings of the Definition and Determination of Death: A Scoping Review
Authors: Zheng Katina , Sutherland Stephanie , Hornby Laura , Wilson Lindsay , Shemie Sam D. , Sarti Aimee J.
Published: March 2022

Background.

During the 1950s, advances in critical care, and organ transplantation altered the relationship between organ failure and death. There has since been a shift away from traditional cardiocirculatory based to brain-based criteria of death, with resulting academic controversy, despite the practice being largely accepted worldwide. Our objective is to develop a comprehensive description of the current understandings of healthcare professionals regarding the meaning, definition, and determination of death.

Methods.

Online databases were used to identify papers published from 2003 to 2020. Additional sources were searched for conference proceedings and theses. Two reviewers screened papers using predefined inclusion and exclusion criteria. Complementary searches and review of reference lists complemented the final study selection. A data extraction instrument was developed to iteratively chart the results of the review. A qualitative approach was conducted to thematically analyze the data.

Results.

Seven thousand four hundred twenty-eight references were identified. In total, 75 papers met the inclusion criteria. Fourteen additional papers were added from complementary searches. Most were narratives (35%), quantitative investigations (21%), and reviews (18%). Identified themes included: (1) the historical evolution of brain death (BD), (2) persistent controversies about BD and death determination, (3) wide variability in healthcare professionals’ knowledge and attitudes, (4) critical need for BD determination revision.

Conclusions.

We concluded that although BD is widely accepted, there exists variation in healthcare providers’ understanding of its conceptual basis. Death determination remains a divisive issue among scholars. This review identified a need for increased opportunities for formal training on BD among healthcare providers.