bluuebunny/crossref_metadata_2025 huggingface dataset:
Platelet‐rich plasma for androgenic alopecia: A randomized, placebo‐controlled, double‐blind study and combined mice model experiment
Authors: Qu Qian , Zhou Yi , Shi Panli , Du Lijuan , Fan Zhexiang , Wang Jin , Li Xin , Chen Jian , Zhu Decong , Ye Ke , Hu Zhiqi , Miao Yong
Published: March 2021

Background

Platelet rich plasma (PRP) has been accepted as a potential therapy for treating androgenetic alopecia (AGA).

Objective

To fully clarify the underling molecular mechanisms of PRP action on hair growth and promote its clinical applications.

Methods

In this study, we used mice models and protein biochip to explore the specific mechanisms of PRP regulating hair growth. Then, we performed a randomized, placebo‐controlled, double‐blind, half‐head study of 52 AGA patients to verify the therapeutic efficacy of PRP in Chinese AGA patients.

Results

The results confirmed that PRP treatment boosted hair regrowth, accelerated hair cycling, and the effect sustained for more than one hair cycle in mice. Protein biochip evaluation confirmed remarkably upregulated β‐Catenin, PDGF, and AKT signaling and repressed p53 signaling in PRP injection group. Clinically, mean hair count, density, diameter, and anagen hair ratio in PRP group showed a significant improvement at 6 month comparing to control side.

Conclusions

Overall, we elucidated the specific molecular mechanism of PRP action on hair growth and proved the therapeutic efficacy and safety of PRP in Chinese AGA patients.
Rock magnetism of ejected basaltic boulders from Lonar crater, India: Implications for the existence of a short‐lived impact‐generated weak magnetic field
Authors: Arif M. , Misra Saumitra
Published: March 2021

The continuous ejecta deposit around the rim of Lonar impact crater, central India, contains angular basaltic boulders of size ≤5 m. These boulders experienced varying level of shock between 2–30 GPa due to impact, as indicated by the extreme fracturing of these basaltic boulders, fragmentation of plagioclase and titanomagnetite constituents of these ejected boulders, and the presence of maskelynite in them. We measure some rock magnetic properties, e.g., NRM/χ (natural remanent magnetization [NRM]/bulk magnetic susceptibility [χ]), REM (=NRM/saturation isothermal remanent magnetization [SIRM] ratio expressed in %), and anisotropy of magnetic susceptibility (AMS) on 53 subsamples from 18 oriented drill cores of the shocked ejected basaltic boulders from the eastern half of ejecta deposit in the present study. The measured data are similar in many respects to our previous observations on Lonar crater rim shocked basalts (Arif et al. 2012b). For example, a small population of the ejected basaltic boulder samples show very high NRM/χ (between 378 and 989 Am−1; n = 7) and REM (between 1.5 and 7%; n = 4) and the AMS axes of these ejected basaltic boulders show triaxial distributions in stereographic projections. Moreover, some of the ejected basaltic boulders show higher values of squareness ratio (Mrs/Ms) and median destructive field (MDF) suggesting permanent changes in the intrinsic magnetic properties due to impact shock pressure. In stereographic plot, the high coercivity and high temperature (HC_HT) magnetization component of these ejected basaltic boulders are distributed in discrete clusters on the periphery of a small enveloping circle whose center (D = 108.0°, I = +69.2°) lies close to the HC_HT cluster of the crater rim shocked basalts. The center of this enveloping circle and the average HC_HT component of Lonar crater rim shocked basalts have the same statistical orientation, although the former has steeper dip. This distribution suggests the possibility that the ejected basaltic boulders, which were deposited during the modification stage of Lonar crater evolution, were magnetized in an impact‐induced magnetic field that was rapidly decaying just after the impact. Our present study suggests that the ejected basaltic boulders and Lonar crater rim shocked basalts experienced high shock pressure (≥2 GPa) magnetization during impact.
Speaker's reference, semantic reference, sneaky reference
Authors: Michaelson Eliot
Published: March 2021

According to what is perhaps the dominant picture of reference, what a referential term refers to in a context is determined by what the speaker intends for her audience to identify as the referent. I argue that this sort of broadly Gricean view entails, counterintuitively, that it is impossible to knowingly use referential terms in ways that one expects or intends to be misunderstood. Then I sketch an alternative which can better account for such opaque uses of language, or what I call “sneaky reference.” I close by reflecting on the ramifications of these arguments for the theory of meaning more broadly.
Dissecting lesions in a culprit artery of a hemorrhagic focus in the basal ganglia: Histopathological analysis by serial sectioning
Authors: Takada Aya , Saito Kazuyuki , Sakai Kentaro
Published: March 2021

In a hypertensive hemorrhagic focus of the basal ganglia, the culprit arteries have been reported to be associated with dissecting lesions, whose topographical relationship to the rupture sites remains to be clarified. Herein we describe multiple dissecting lesions in the culprit artery of hypertensive hemorrhage of the basal ganglia. A 1.0 × 0.8 × 0.8 cm‐sized bleeding globe was confirmed at a left lenticulostriate artery and histologically analyzed by serial sectioning. Three independent dissecting lesions were identified in the culprit artery. They were situated near the bifurcations, ranging from 240 to 3200 μm in length. The dissections mainly occurred between the intima and media with disruption of the internal elastic lamina (IEL), forming a fresh thrombus within the false lumen. Two rupture sites causing the cerebral hematoma were confirmed away from the dissecting lesions. One was situated close but not adjacent to the longest dissecting lesion; the other, measuring approximately 150 μm in diameter, was adjacent to the bifurcation of an artery. The histopathological findings suggest that the dissecting lesion resulted from medial detachment following IEL disruption in the process of arterial rupture of the culprit artery. We conclude that this was a secondary manifestation during the rupture rather than a cause of the arterial rupture.
Safety and Efficacy of Minimally Invasive Transforaminal Lumbar Interbody Fusion Combined with Gelatin Sponge Impregnated with Dexamethasone and No Drainage Tube after Surgery in the Treatment of Lumbar Degenerative Disease
Authors: Du Jin‐Peng , Wang Xiao‐Hui , Shan Le‐Qun , Wang Wen‐Tao , Li Hou‐Kun , Huang Da‐Geng , Yan Liang , Hao Ding‐Jun
Published: March 2021

Objective

The aim of the present study was to use a gelatin sponge impregnated with dexamethasone, combined with minimally invasive transforaminal lumbar interbody fusion (MIS‐TLIF) and no drainage tube after the operation for early postoperative recurrence of root pain caused by edema.

Methods

A prospective case series study was designed. From September 2015 to January 2018, eligible patients diagnosed with lumbar degenerative disease underwent MIS‐TLIF combined with a gelatin sponge impregnated with dexamethasone and no drainage tube after surgery. The short‐term clinical data were collected, such as visual analog scale (VAS) scores for low back pain and leg pain preoperatively and on postoperative days (POD) 1–10, time bedridden postoperatively, and length of hospital stay postoperatively. Long‐term indicators include the Japanese Orthopaedic Association (JOA) score, the Oswestry Disability Index (ODI) score, and the 36‐Item Short‐Form Health Survey (SF‐36) score, evaluated preoperatively and 1 week, 3 months, and more than 1 year postoperatively.

Results

Complete clinical data was obtained for 139 patients. All patients were followed up for more than 12 months (13.7 ± 3.3 months). The average bedridden period was 1.5 ± 0.4 days and hospital stays were 2.7 ± 0.9 days. The VAS score of leg and back pain on POD 1–10 were all decreased compared with preoperation (all P < 0.0001). At the last follow up, the VAS scores for back pain and leg pain (0.69 ± 0.47; 1.02 ± 0.55) and the ODI score (11.1 ± 3.5) decreased (all P < 0.0001), and the JOA score (27.1 ± 3.2) and the SF‐36 (physical component summary, 50.5 ± 7.3; mental component summary, 49.4 ± 8.9) increased (all P < 0.0001) compared with preoperative values. Patients' early and long‐term levels of satisfaction postoperatively were 92.8% and 97.8%, respectively. At POD 7 and the last follow‐up, the improvement rate of the JOA score, respectively, was 41.8% ± 10.6% and 87.7% ± 8.2%, and clinical effects assessed as significantly effective according to the improvement rate of the JOA score was 16.5% and 66.9%, respectively. There were 2 (1.4%) cases with complications, including 1 (0.7%) case of wound infection and 1 (0.7%) case of deep vein thrombosis. There were no device‐related complications or neurological injuries.

Conclusion

Use of a gelatin sponge impregnated with dexamethasone combined with MIS‐TLIF and no drainage tube after the operation, compared with previous studies, appears to be safe and feasible to reduce recurrent back pain and leg pain after decompression in the treatment of lumbar degenerative disease.
‘The bang was not as loud as I had expected’
Authors: Simchen Ori
Published: March 2021

In 442 of Philosophical Investigations, Wittgenstein criticises the application of Russell's theory of descriptions to the sentence in the title without mentioning Russell or his theory. Wittgenstein is making a general point of wider interest. I have two aims. The first is to situate Wittgenstein's critique within the larger theoretical setting of Russell's theory of descriptions and Frege's theory of indirect reference in light of the familiar problem of quantifying into attitude contexts. The second is to draw broader methodological implications from the foregoing for how best to think of the role of individual semantic paraphrases within the formal semantic study of natural language.
Pathology of salivary gland dysfunction and restoration of function
Authors: Saito Ichiro
Published: March 2021

In this review, the author shows that simultaneous multiple disorders caused by reactivation of Epstein–Barr virus can lead to salivary gland disorders as part of Sjogren's syndrome (SS). Therefore, clinicians must differentiate SS from other diseases when diagnosing and treating salivary gland disorders. In particular, the author explains how microbial infection in SS overcomes immunological tolerance, leading to pathological changes, and how cytokine overexpression and endocrine disrupters contribute to glandular tissue injury. Also, the author suggests that involvement of reactive oxygen species is a common pathogenesis of salivary gland disorders and SS, so regulation of oxidative stress is an effective treatment for both. The results of clinical studies on restoring salivary gland function and regenerating salivary glands with tissue stem cells may provide clues on elucidating the cause of SS.
Leaf N content regulates the speed of photosynthetic induction under fluctuating light among canola genotypes (Brassica napus L.)
Authors: Liu Jiahuan , Zhang Jing , Estavillo Gonzalo M. , Luo Tao , Hu Liyong
Published: March 2021

Nitrogen is an essential element for plant growth, and the relationship between leaf N content and photosynthesis has been widely studied in different species under steady‐state light. However, under natural conditions, the light intensity at the leaf level is always changing, inherently heterogeneous in time and space. Therefore, the effect of leaf N content on photosynthesis under dynamic light conditions needs further study. At present, the effects of leaf N content on leaf non‐steady‐state photosynthesis have not been reported in canola (Brassica napus L.). To clarify the relationship between leaf N content and the speed of the response leaf gas exchange to variations in light intensity, eight genotypes of canola varying in leaf N content were used to study the temporal response of gas exchange to a step increase in irradiance. We found there were significant differences in non‐steady‐state photosynthesis, physiological characteristics, and anatomical traits across genotypes (the maximum amplitude was about fivefold), despite the lack of contrast under normal, steady‐state photosynthesis. In addition, initial stomatal conductance to water vapor in the darkness and leaf N content per leaf area were negatively correlated with the time required to achieve 50% and 100% of the maximum photosynthetic rate. Contrarily, the time required to reach 50% of the maximum stomatal conductance was positively correlated with the time required to achieve 90% of the maximum photosynthetic rate across genotypes. It is concluded that the genotypes of canola with higher N content per leaf area show a faster induction of photosynthesis to fluctuating light conditions.
Nitrification and denitrification in recirculating aquaculture systems: the processes and players
Authors: Preena Prasannan Geetha , Rejish Kumar Vattiringal Jayadradhan , Singh Isaac Sarojini Bright
Published: March 2021

One of the major challenges in any sustainable aquaculture production systems is the accumulation of nitrogenous waste such as ammonia and its biological nitrification products viz nitrite and nitrate. Considering the bio‐security issues, amelioration of these wastes without water exchange can be accomplished only by way of establishing in situ nitrification and denitrification through biofilters/bioreactors activated with nitrifying/denitrifying bioaugmentors. In such systems, coexistence of aerobic denitrifiers, anaerobic ammonia oxidizers (Anammox) and complete ammonia oxidizers (Comammox) together with the autotrophic nitrifiers enhance the coupled nitrification–denitrification. This promotes total nitrogen removal without external carbon supplements or additional anerobic compartment in the system. Various recirculating aquaculture systems (RAS) comprise diverse nitrifying community in biofilters/bioreactors thereby imparting distinctive nitrogen conversion in the system. Meanwhile, the structure and population dynamics of the nitrifying/denitrifying consortia are influenced by the environmental factors forming the decisive factors of the success of the processes. Accordingly, understanding the complexity of nitrifying/denitrifying community composition turns out to be a requirement to facilitate its improvised performance. In this context, the review addresses different biological nitrogen removal systems, significance of nitrification–denitrification in RAS, genetic diversity of the key players in RAS, methods of analysis of their community structure, current application and prospects of the processes in RAS.
Untreated dental disease and lung transplant waitlist evaluation time for individuals with cystic fibrosis
Authors: Alkhateeb Alaa A. , Lease Erika D. , Mancl Lloyd A. , Chi Donald L.
Published: March 2021

Aims

Dental clearance is typically part of the evaluation process prior to placement on the lung transplant waiting list. Individuals with cystic fibrosis (CF) are thought to be at low risk for dental disease. We hypothesized that individuals with CF in need of lung transplantation would have lower dental disease prevalence and shorter waitlist evaluation time than individuals with non‐CF lung diseases.

Methods and Results

We conducted a retrospective study of individuals who received a lung transplant between 2011 and 2017 at the University of Washington (Seattle, WA, USA) (N = 280). Untreated dental disease was assessed by the individual's dentist. Waitlist evaluation time was defined as the time, in days, from the initial evaluation by a transplant pulmonologist to placement on the lung transplant waiting list. We used logistic and linear regression models for hypothesis testing. The prevalence of untreated dental disease did not differ by CF status (p = 0.99). There was no difference in waitlist evaluation time for transplant recipients by CF status (p = 0.78) or by dental disease status (p = 0.93).

Conclusions

Our findings provide further evidence that individuals with CF are not at low risk for dental disease. Ensuring optimal oral health is important for all individuals with lung diseases.
A Recipe for Madness: Parenthood in the Era of Covid‐19
Authors: Elder Laurel , Greene Steven
Published: March 2021

Objectives

This article seeks to understand the economic, mental health, and political impacts on American parents in the era of Covid‐19.

Methods

We draw on survey data from a diverse national sample collected in September 2020 and employ multivariate analysis to explore how Covid‐19 has uniquely affected the attitudes and life experiences of American parents.

Results

We find that Covid‐19 has been unusually burdensome for parents as they are more likely to have experienced negative physical and mental health outcomes and suffer more negative financial impacts. Despite the challenges parents face, they also remain cautious about in‐person school and vaccinations. Although mothers have been the focus of much news coverage, we find that both mothers and fathers have been similarly and negatively impacted by Covid‐19.

Conclusion

American parents are suffering at distinctively high levels during this pandemic. In order to recover, policymakers will need to target outreach and support tailored to the needs and issues facing parents.
Deterrents in recruitment of COVID‐19 convalescent plasma donors: Experience from a hospital‐based blood centre in India
Authors: Dhiman Yashaswi , Coshic Poonam , Pandey Hem Chandra , Khatiwada Basanta , Singh Jasmeet , Mehta Vikas , Gupta Sanjay
Published: March 2021

Introduction

Recruitment of Covid‐19 convalescent plasma (CCP) donors may present as a challenge due to inexperience and differences in donor profile as compared to whole blood donation. Present study highlights the deterrents to recruiting CCP donors at a hospital based blood centre.

Materials and methods

Potential CCP donors were contacted individually by telephone and a group approach through camp organisers from May to July 2020. Recruitment challenges were noted and deferrals of these recruited donors during screening and medical examination was obtained and analysed.

Results

Total 1165 potential CCP donors were contacted. Around 47% donors were lost due to challenges related to information storage and retrieval. Fear of health, family pressure, and fear of a new procedure were major reason (27.2%) for unwillingness to donate. The main reasons for deferral among potential donors were multiparity (38%) and being overage/underage (31.6%). Finally, 468 donors were recruited including 408 by individual approach and 60 by a group approach. From these absence of detectable COVID‐19 antibodies were found in 15.4%. Few donors (9.0%) were deferred as they had not completed 28 days post recovery.

Conclusion

The process of CCP donor recruitment differs from that of whole blood donation and requires an individualised approach with involvement of clinicians in the initial phases of the pandemic. A group approach targeting specific organisations could be adopted for a successful CCP collection program. There is a need to relook into some aspects of donor selection such as consideration of multiparous female donors and overage/underage donors after reviewing scientific evidence.
Lumbosacral intervertebral disk extrusions in 13 dogs
Authors: Bresciani Luca , Trevail Raquel , Clarke Stephen , Gutierrez‐Quintana Rodrigo , Behr Sebastien , Lazzerini Kali , Brocal Josep , Oxley Bill , Pink Jonathan , José‐López Roberto
Published: March 2021

Objective

To describe the clinical presentation, magnetic resonance imaging (MRI) findings, and outcome of dogs treated surgically for lumbosacral intervertebral disk extrusion (IVDE).

Study Design

Retrospective study.

Animals

Thirteen dogs.

Methods

Records and MRI studies of dogs with intraoperatively confirmed lumbosacral IVDE were reviewed. MRI features of thoracolumbar IVDE were applied to all cases. Postoperative outcome was subjectively assessed as excellent, good, or poor.

Results

All dogs had an acute or subacute onset of lumbosacral pain and nerve root signature. Seven dogs had neurological deficits. MRI revealed lateralized herniated disk material and partial to complete disk degeneration in all cases; the extradural material extended cranial and/or caudally from the disk space in 10 cases. All dogs underwent L7‐S1 dorsal laminectomy and removal of extruded disk material. In six dogs, surgery was complicated by inflammatory changes, including one case of epidural steatitis. On reexamination 4–6 weeks postsurgery, outcome was judged as excellent in 11 dogs and poor in the remaining 2 due to contralateral nerve root signature in one case and nonambulatory paraparesis and urinary incontinence in the case with steatitis.

Conclusion

Lumbosacral IVDE in dogs was characterized by acute/subacute onset of lumbosacral pain and nerve root signature and lateralized and often dispersed extradural material over a degenerated L7‐S1 intervertebral disk on MRI. Early decompressive dorsal laminectomy generally resulted in excellent clinical outcome.

Clinical Significance

Observation of these clinical and imaging features in dogs should prompt clinical suspicion of lumbosacral IVDE.
Depth-graded motivic multiple zeta values
Authors: Brown Francis
Published: March 2021

We study the depth filtration on multiple zeta values, on the motivic Galois group of mixed Tate motives over $\mathbb {Z}$ and on the Grothendieck–Teichmüller group, and its relation to modular forms. Using period polynomials for cusp forms for $\mathrm {SL} _2(\mathbb {Z})$, we construct an explicit Lie algebra of solutions to the linearized double shuffle equations, which gives a conjectural description of all identities between multiple zeta values modulo $\zeta (2)$ and modulo lower depth. We formulate a single conjecture about the homology of this Lie algebra which implies conjectures due to Broadhurst and Kreimer, Racinet, Zagier, and Drinfeld on the structure of multiple zeta values and on the Grothendieck–Teichmüller Lie algebra.
On the Validation of Turbulence Models for Wheel and Wheelhouse Aerodynamics
Authors: Nabutola Kaloki L. , Boetcher Sandra K. S.
Published: March 2021

Vehicle aerodynamics plays an important role in reducing fuel consumption. The underbody contributes to around 50% of the overall drag of a vehicle. As part of the underbody, the wheels and wheelhouses contribute to approximately 25–30% of the overall drag of a vehicle. As a result, wheel aerodynamics studies have been gaining popularity. However, a consensus of an appropriate turbulence model has not been reached, partially due to the lack of experiments appropriate for turbulence model validation studies for this type of flow. Seven turbulence models were used to simulate the flow within the wheelhouse of a simplified vehicle body, and results were shown to be incongruous with commonly used experimental data. The performance of each model was evaluated by comparing the aerodynamic coefficients obtained using computational fluid dynamics (CFD) to data collected from the Fabijanic wind tunnel experiments. The various turbulence models generally agreed with each other when determining average values, such as mean drag and lift coefficients, even if the particular values did not fall within the uncertainty of the experiment. However, they exhibited differences in the level of resolution in the flow structures within the wheelhouse. These flow structures are not able to be validated with currently available experimental data. Properly resolving flow structures is important when implementing flow-control devices to reduce drag. Results from this study emphasize the need for spatially and time-resolved experiments, especially for validating large eddy simulation (LES) and detached eddy simulation (DES) for flow within a wheelhouse.
Neural Network-Based Transfer Learning of Manipulator Inverse Displacement Analysis
Authors: Tang Houcheng , Notash Leila
Published: March 2021

In this paper, the feasibility of applying transfer learning for modeling robot manipulators is examined. A neural network-based transfer learning approach of inverse displacement analysis of robot manipulators is studied. Neural networks with different structures are applied utilizing data from different configurations of a manipulator for training purposes. Then, the transfer learning was conducted between manipulators with different geometric layouts. The training is performed on both the neural networks with pretrained initial parameters and the neural networks with random initialization. To investigate the rate of convergence of data fitting comprehensively, different values of performance targets are defined. The computing epochs and performance measures are compared. It is presented that, depending on the structure of the neural network, the proposed transfer learning can accelerate the training process and achieve higher accuracy. For different datasets, the transfer learning approach improves their performance differently.
Fault-Tolerant Control of Programmable Logic Controller-Based Production Systems With Deep Reinforcement Learning
Authors: Zinn Jonas , Vogel-Heuser Birgit , Gruber Marius
Published: March 2021

Fault-tolerant control policies that automatically restart programable logic controller-based automated production system during fault recovery can increase system availability. This article provides a proof of concept that such policies can be synthesized with deep reinforcement learning. The authors specifically focus on systems with multiple end-effectors that are actuated in only one or two axes, commonly used for assembly and logistics tasks. Due to the large number of actuators in multi-end-effector systems and the limited possibilities to track workpieces in a single coordinate system, these systems are especially challenging to learn. This article demonstrates that a hierarchical multi-agent deep reinforcement learning approach together with a separate coordinate prediction module per agent can overcome these challenges. The evaluation of the suggested approach on the simulation of a small laboratory demonstrator shows that it is capable of restarting the system and completing open tasks as part of fault recovery.
Properties of indium tin oxide thin films grown by Ar ion beam sputter deposition
Authors: Bundesmann Carsten , Bauer Jens , Finzel Annemarie , Gerlach Jürgen W. , Knolle Wolfgang , Hellmich Anke , Synowicki Ron
Published: March 2021

Indium tin oxide (ITO) thin films were grown by Ar ion beam sputter deposition under systematic variation of ion energy, geometrical parameters, and O2 background pressure and characterized with regard to the film thickness, growth rate, crystalline structure, surface roughness, mass density, composition, electrical, and optical properties. The growth rate shows an over-cosine, forward-tilted angular distribution with a maximum, which increases with increasing ion energy, increasing ion incidence angle, and decreasing O2 background pressure. ITO films were found to be amorphous with a surface roughness of less than 1 nm. Mass density and composition show only small changes with increasing scattering angle. The electrical resistivity behavior in dependence on the process parameters is complex. It is not only driven by the O2 background pressure but also very much by the scattering angle. The observed behavior can be understood only if competing processes are considered: (i) reduction of the number of oxygen vacancies due to the presence of O2 background gas and (ii) defect generation and preferential sputtering of oxygen at the surface of the growing films due to the impact of high-energy scattered particles. Even though absolute numbers differ, optical characterization suggests a similar systematics.
The rolling elliptical cylinder
Authors: Lindén Johan , Källman Kjell-Mikael , Lindberg Markus
Published: March 2021

Solving the equations of motion for a cylinder with elliptical cross section rolling down an inclined plane constitutes a rather challenging problem. Using Lagrangian mechanics, we have derived the equations of motion analytically and the resulting differential equations are solved numerically. Using a CNC milling machine, we manufactured a solid elliptic cylinder and recorded its dynamics using a high-speed video camera for various inclinations of the plane. We compared theory and experiment by extracting the center of mass coordinates and the angular velocity from the video recording. Limits imposed by the support force reaching zero and insufficient friction to prevent slipping were examined both experimentally and theoretically.
The bound-state solutions of the one-dimensional hydrogen atom
Authors: Boyack Rufus , Marsiglio Frank
Published: March 2021

The one-dimensional hydrogen atom is an intriguing quantum mechanics problem that exhibits several properties which have been continually debated. In particular, there has been variance as to whether or not even-parity solutions exist, and specifically whether or not the ground state is an even-parity state with infinite negative energy. We study a “regularized” version of this system, where the potential is a constant in the vicinity of the origin, and we discuss the even- and odd-parity solutions for this regularized one-dimensional hydrogen atom. We show how the even-parity states, with the exception of the ground state, converge to the same functional form and become degenerate for x > 0 with the odd-parity solutions as the cutoff approaches zero. This differs with conclusions derived from analysis of the singular (i.e., without regularization) one-dimensional Coulomb potential, where even-parity solutions are absent from the spectrum.
Digital imaging of a random walk by computer simulation: Using a simple model to interpret the effects of finite spatio-temporal resolution
Authors: Patra Swayamshree , Dey Swagata , Ray Krishanu , Chowdhury Debashish
Published: March 2021

We discuss computer simulations of a particle that hops forward and backward randomly on a one-dimensional lattice. To track the motion of the particle, we use a data acquisition protocol that mimics a virtual digital optical imaging system. Plots of the data extracted from these images yield a pattern that is similar to the patterns observed in real imaging of a moving particle in a living cell. To explore the physical origin of the observed patterns, we use different spatio-temporal resolutions and show that the characteristics of the observed patterns are determined by the spatial and temporal resolutions of the digital imaging device. The simulations help not only to determine the origin of these patterns in the imaging data, but also to avoid misinterpreting the imaging data in terms of a special property of the particle or its dynamics.
Euler's rigid rotators, Jacobi elliptic functions, and the Dzhanibekov or tennis racket effect
Authors: Peterson Christian , Schwalm William
Published: March 2021

In this paper, the torque-free rotational motion of a general rigid body is developed analytically and is applied to the flipping motion of a T-handle spinning in zero gravity that can be seen in videos on the internet. This flipping motion is known both as the Dzhanibekov effect (after the cosmonaut who reported it) and more recently the tennis racket effect. The presentation is self-contained, accessible to students, and is complementary to the treatment found in most texts in that it involves a time-dependent analytical solution in terms of elliptic functions as opposed to a development based on conservation laws. These two complementary approaches are interesting and useful in different ways. In the present approach, the Euler rigid-body equations are derived and then solved as differential equations that are satisfied by Jacobi elliptic functions. This is analogous to solving the spring–mass harmonic oscillator problem by turning Newton's laws into differential equations that are satisfied by sine and cosine functions. The Jacobi functions are closely related to these trigonometric functions and are only slightly more complicated. They are defined as geometrical ratios on a reference ellipse and developed geometrically without reference to power series or complex variables. However, because these functions are less familiar, they are introduced in a short Appendix where their main properties are derived. Also, a link is provided to a Mathematica script for animating the analytical solution to the present problem.
The mobile phone as a free-rotation laboratory
Authors: Wheatland Michael S. , Murphy Tara , Naoumenko Daniel , Schijndel Daan van , Katsifis Georgio
Published: March 2021

Modern mobile phones contain a three-axis microelectromechanical system (MEMS) gyroscope, capable of taking accurate measurements of the angular velocity along the three principal axes of the phone with a sampling rate of 100 Hz or better. If the phone is tossed in the air, then, neglecting air resistance, it is in free rotation (rotation in the absence of a torque) with respect to its centre of mass, and the phone's gyroscope can be used to record the rotational dynamics. This enables experimental investigation of free rotation. In this paper, we use a mobile phone to demonstrate the steady states for rotation of the phone about two of its principal axes, and the instability in rotation about the third corresponding to the intermediate moment of inertia. We also show the approximate conservation of angular momentum and rotational kinetic energy during motion in the air, and compare the data with numerical solution of Euler's equations for free rotation. Our results demonstrate the capability of smartphones for investigating free rotation, and should be of interest to college and university teachers developing “at home” physics labs for remote learning.
The evolutionary history of Neanderthal and Denisovan Y chromosomes
Authors: Petr Martin , Hajdinjak Mateja , Fu Qiaomei , Essel Elena , Rougier Hélène , Crevecoeur Isabelle , Semal Patrick , Golovanova Liubov V. , Doronichev Vladimir B. , Lalueza-Fox Carles , de la Rasilla Marco , Rosas Antonio , Shunkov Michael V. , Kozlikin Maxim B. , Derevianko Anatoli P. , Vernot Benjamin , Meyer Matthias , Kelso Janet
Published: March 2021

Y chromosome evolution in Neanderthals

The genomes of archaic hominins have been sequenced and compared with that of modern humans. However, most archaic individuals with high-quality sequences available have been female. Petr
et al.
performed targeted sequencing of the paternally inherited Y chromosomes from three Neanderthals and two Denisovans (see the Perspective by Schierup). Comparisons with available archaic and diverse modern human Y chromosomes indicated that, similar to the maternally inherited mitochondria, the human and Neanderthal Y chromosomes were more closely related to each other compared with the Denisovan Y chromosome. This result supports the conclusion that interbreeding between early humans and Neanderthals and selection replaced the more ancient Denisovian-like Y chromosome and mitochondria in Neanderthals.

Science
, this issue p.
1653
; see also p.
1565
Intense x-rays can be (slightly) exciting
Authors: Pfeifer Thomas
Published: March 2021

Imaging of neutral “survivor” atoms excited by x-ray blasts fights radiation damage
Birds do have a brain cortex—and think
Authors: Herculano-Houzel Suzana
Published: March 2021

Like mammals, birds have a pallium that sustains correlates of consciousness
Role of Phylogenetic Structure in the Dynamics of Coastal Viral Assemblages
Authors: Gustavsen Julia A. , Suttle Curtis A.
Published: March 2021

Viruses are major agents of microbial mortality in marine systems, yet little is known about changes in the composition of viral assemblages in relation to those of the microbial communities that they infect. Here, we sampled coastal seawater every 2 weeks for 1 year and used high-throughput sequencing of marker genes to follow changes in the composition of two groups of ecologically important viruses, as well as the communities of bacteria and protists that serve as their respective hosts.
Whole-Genome Transformation Promotes tRNA Anticodon Suppressor Mutations under Stress
Authors: Deparis Quinten , Duitama Jorge , Foulquié-Moreno Maria R. , Thevelein Johan M.
Published: March 2021

In this work, we have identified for the first time the causative elements in a eukaryotic organism introduced by applying whole-genome transformation and responsible for the selectable trait of interest, i.e., high temperature tolerance. Surprisingly, the whole-genome transformants contained just a few single nucleotide polymorphisms (SNPs), which were unrelated to the sequence of the donor DNA.
Integrative Transkingdom Analysis of the Gut Microbiome in Antibiotic Perturbation and Critical Illness
Authors: Haak Bastiaan W. , Argelaguet Ricard , Kinsella Cormac M. , Kullberg Robert F. J. , Lankelma Jacqueline M. , Deijs Martin , Klein Michelle , Jebbink Maarten F. , Hugenholtz Floor , Kostidis Sarantos , Giera Martin , Hakvoort Theodorus B. M. , de Jonge Wouter J. , Schultz Marcus J. , van Gool Tom , van der Poll Tom , de Vos Willem M. , van der Hoek Lia M. , Wiersinga W. Joost
Published: March 2021

While numerous studies have characterized antibiotic-induced disruptions of the bacterial microbiome, few studies describe how these disruptions impact the composition of other kingdoms such as viruses, fungi, and protozoa. To address this knowledge gap, we employed MOFA
+
to systematically integrate viral, fungal, and bacterial sequence data from critically ill patients (with and without sepsis) and healthy volunteers, both prior to and following exposure to broad-spectrum antibiotics.
New zircon radiometric U-Pb ages and Lu-Hf isotopic data from the ultramafic-mafic sequences of Ranau and Telupid (Sabah, eastern Malaysia): Time to reconsider the geological evolution of Southeast Asia?
Authors: Tsikouras Basilios , Lai Chun-Kit , Ifandi Elena , Norazme Nur’Aqidah , Teo Chee-Hui , Xia Xiao-Ping
Published: March 2021

New zircon U-Pb geochronology from a peridotite suite near Ranau and the Telupid ophiolite in Sabah, eastern Malaysia, contradict previous studies, which assumed that the Sabah mafic-ultramafic rocks are largely ophiolitic and Jurassic–Cretaceous in age. We show that these rocks formed during a magmatic episode in the Miocene (9.2–10.5 Ma), which is interpreted to reflect infiltration of melts and melt-rock reaction in the Ranau subcontinental peridotites during extension, and concurrent seafloor spreading forming the Telupid ophiolite further south. Older zircons from the Ranau peridotites have Cretaceous, Devonian, and Neoproterozoic ages. Zircon Lu-Hf isotopic data suggest their derivation from a depleted mantle. However, significant proportions of crustal components have been incorporated in their genesis, as evidenced by their less-radiogenic Hf signature compared to a pristine mantle reservoir. The involvement of a crustal component is consistent with our interpreted continental setting for the Ranau peridotite and formation in a narrow backarc basin for the Telupid ophiolite. We infer that the Sulu Sea, which was expanding throughout much of the Miocene, may have extended to the southwest into central Sabah. The Telupid oceanic strand formed during the split, collapse, and rollback of the Sulu arc due to the subduction of the Celebes Sea beneath Sabah. Incorporation of the Sulu arc in the evolving Miocene oceanic basin is a potential source to explain the involvement of crustal material in the zircon evolution of the Telupid ophiolite.
Unexpected severe intra-abdominal injuries resulting from a ground-level fall in an elderly patient with a large staghorn calculus
Authors: Lightfoot Alexandre , Chan James
Published: March 2021

A 70-year-old woman on warfarin was transported to the emergency department after a ground-level fall, injuring her left backside. Criteria for geriatric trauma activation was not met. An episode of haematuria created suspicion for an intra-abdominal injury, prompting a point-of-care ultrasound (POCUS) Focused Assessment with Sonography for Trauma scan, which was positive. Subsequent pan-scanning discovered a multitude of injuries, including low-grade left renal and splenic lacerations, multiple left rib fractures and a haemothorax. Patient also had a supratherapeutic International Normalized Ratio (INR), which was reversed with 4-factor Prothrombin Complex Concentrate (4F-PCC). She was admitted to the intensive care unit, underwent urgent thoracostomy and had a complicated hospital course. Moreover, an incidental large staghorn calculus in the left kidney might have contributed shearing forces. In summary, under triage of this patient emphasised the importance of performing detailed primary and secondary surveys, including POCUS, for all geriatric ground-level fall patients on anticoagulants to allow for rapid diagnosis and treatment of potential serious injuries.
Nearly fatal hypokalaemia due to non-hypertensive primary hyperaldosteronism in the post partum
Authors: Marques-Sá Juliana , Barbosa Mariana , Fernandes Vera , Santos Maria Joana
Published: March 2021

A previously healthy postpartum 33-year-old woman was admitted at the emergency department after two episodes of syncope. In the waiting room, she collapsed, ventricular fibrillation was detected, and she was reanimated by electric cardioversion. At admission, she was conscient, with blood pressure of 102/74 mm Hg and heart rate of 78 bpm. In the laboratory workup, severe hypokalaemia was found (K+1.77 mEq/L). Abdominopelvic CT revealed a 27 mm nodule in the right adrenal gland. High aldosterone and low plasma renin levels were detected, and the diagnosis of primary hyperaldosteronism was made, although she never had hypertension. Posteriorly, a cosecretion of aldosterone and cortisol was found. Two months after admission, the patient remained stable with normal K+levels under spironolactone and a right adrenalectomy was performed. The cure of primary hyperaldosteronism and a partial adrenal insufficiency were confirmed. K+levels and blood pressure remained normal without treatment and 10 months after surgery hydrocortisone was suspended.
Unusual cause of acute upper airway obstruction: spontaneous pharyngeal haematoma
Authors: Okada Kohei , Okazaki Yuji , Ichiba Toshihisa , Higashi Yusuke
Published: March 2021

Spontaneous pharyngeal haematoma is a rare but life-threatening cause of acute upper airway obstruction, and the clinical manifestation may mimic haemoptysis. A 65-year-old man presented to our emergency department with symptoms of sore throat and haemoptysis. He had no medical history. At arrival, O2saturation was 95% on 5 L/min of oxygen with a mask. Results of a blood examination including a coagulation test were normal. Laryngoscopy showed enlargement of the left pharynx and a narrowed airway. Contrast-enhanced CT showed extravascular leakage of contrast medium inside the left pharyngeal haematoma. Fortunately, the haematoma did not lead to airway obstruction, and it decreased spontaneously. We finally diagnosed this case as spontaneous pharyngeal haematoma. When we examine a patient with a symptom of haemoptysis accompanied by sore throat, it is necessary to consider pharyngeal haematoma and to prepare emergency airway protection for acute upper airway obstruction.
Symptom cluster is associated with prolonged return-to-play in symptomatic athletes with acute respiratory illness (including COVID-19): a cross-sectional study—AWARE study I
Authors: Schwellnus Martin , Sewry Nicola , Snyders Carolette , Kaulback Kelly , Wood Paola Silvia , Seocharan Ishen , Derman Wayne , Hull James H , Valtonen Maarit , Jordaan Esme
Published: March 2021

Background

There are no data relating symptoms of an acute respiratory illness (ARI) in general, and COVID-19 specifically, to return to play (RTP).

Objective

To determine if ARI symptoms are associated with more prolonged RTP, and if days to RTP and symptoms (number, type, duration and severity) differ in athletes with COVID-19 versus athletes with other ARI.

Design

Cross-sectional descriptive study.

Setting

Online survey.

Participants

Athletes with confirmed/suspected COVID-19 (ARICOV) (n=45) and athletes with other ARI (ARIOTH) (n=39).

Methods

Participants recorded days to RTP and completed an online survey detailing ARI symptoms (number, type, severity and duration) in three categories:‘nose and throat’,‘chest and neck’ and‘whole body’. We report the association between symptoms and RTP (% chance over 40 days) and compare the days to RTP and symptoms (number, type, duration and severity) in ARICOVversus ARIOTHsubgroups.

Results

The symptom cluster associated with more prolonged RTP (lower chance over 40 days; %) (univariate analysis) was‘excessive fatigue’ (75%; p<0.0001), ‘chills’ (65%; p=0.004), ‘fever’ (64%; p=0.004), ‘headache’ (56%; p=0.006),‘altered/loss sense of smell’ (51%; p=0.009), ‘Chest pain/pressure’ (48%; p=0.033), ‘difficulty in breathing’ (48%; p=0.022) and ‘loss of appetite’ (47%; p=0.022). ‘Excessive fatigue’ remained associated with prolonged RTP (p=0.0002) in a multiple model. Compared with ARIOTH, the ARICOVsubgroup had more severe disease (greater number, more severe symptoms) and more days to RTP (p=0.0043).

Conclusion

Symptom clusters may be used by sport and exercise physicians to assist decision making for RTP in athletes with ARI (including COVID-19).
Seroepidemiology of hepatitis A and B in the general population in Hong Kong: protocol of a cross-sectional survey using spatial sampling in a highly urbanised city
Authors: Poon Chin Man , Chan Denise P , Lee Shui Shan , Wong Ngai Sze
Published: March 2021

Introduction

Differences in immunisation policies have significantly reshaped the epidemiology of hepatitis A and B in the population. Assessment of the susceptibility and transmission potential of these two types of vaccine-preventable hepatitis would enhance the capacity of public health authorities for viral hepatitis elimination. Focusing on Hong Kong, the objectives of this study comprise the determination of the population-level seroprevalence of hepatitis A and B and an examination of the risk factors for virus transmission and the population impacts of vaccinations.

Methods and analysis

This is a cross-sectional household survey on hepatitis A and B. By using socially homogeneous building groups as sampling frame, eligible members of 1327 spatially selected households would be invited to complete a questionnaire and provide blood samples for serological testing (anti-hepatitis A virus, hepatitis B surface antigen, hepatitis B surface and core antibody). The main measures comprise a set of metrics on the prevalence of hepatitis A and B. Analysis would be conducted to examine the association of risk factors with the tested markers and describe the attitudes towards viral hepatitis vaccination.

Ethics and dissemination

Ethical approval from the Joint Chinese University of Hong Kong—New Territories East Cluster Clinical Research Ethics Committee, and approval for laboratory safety from the Chinese University of Hong Kong have been obtained. The study results will be presented in scientific forums to update on the epidemiology of hepatitis A and B and inform the development of new vaccination strategies in Hong Kong.

Trial registration number

NCT04371276.