bluuebunny/crossref_metadata_2025 huggingface dataset:
Neurodevelopmental Outcomes following Preterm Birth and the Association with Postmenstrual Age at Discharge
Authors: Kellner Polly , Kwon Jenny , Smith Joan , Pineda Roberta
Published: January 2022

Objective This study aimed to (1) define the prevalence of motor, cognitive, and language delays in preterm infants born <32 weeks estimated gestational age (EGA); and (2) identify the relationship between the timing of discharge from the neonatal intensive care unit (NICU) and neurodevelopmental outcome in early childhood.

Study Design This retrospective study of 172 preterm infants born <32 weeks EGA and hospitalized in a level-IV NICU captured medical factors, including timing of discharge, from the NICU stay. Standardized developmental testing at 1 to 2 years corrected age was conducted in the newborn follow-up clinic.

Results At 1 to 2 years corrected age, the sample had an average Bayley Scales of Infant and Toddler Development (Bayley-III) cognitive composite score of 91.5 ± 17.4, language composite score of 84.5 ± 17.3, and motor composite score of 88.9 ± 18.4. Lower EGA at birth, necrotizing enterocolitis, patent ductus arteriosus, and oxygen requirement for >28 days were independently associated with higher postmenstrual age (PMA) at NICU discharge. Higher PMA at discharge was associated with poorer cognitive outcome [p < 0.001, β = −1.1 (−1.6, −0.7)], poorer language outcome [p = 0.049, β = −0.5 (−0.9, −0.003)], and poorer motor outcome [p <0.001, β = −1.0 (−1.5, −0.5)]. For every additional week of hospitalization, scores were an average of 1.1 points lower in cognitive, 1.0 point lower in motor, and 0.5 points lower in language domains of the Bayley-III assessment.

Conclusion Poorer cognitive, language, and motor outcomes were associated with longer hospitalization, even after controlling for medical risk factors known to be associated with poorer outcome. This provides further evidence for the potential role of the environment in impacting developmental outcomes of infants hospitalized in the NICU.

Key Points
COVID-19-Associated Multisystem Inflammatory Syndrome in a Neonate with Atypical Coronary Artery Involvement
Authors: Costa Simonetta , Delogu Angelica B. , Bottoni Anthea , Purcaro Velia , D'Andrea Vito , Paladini Angela , Muto Sara , Marano Riccardo , Savino Giancarlo , Secinaro Aurelio , De Benedetti Fabrizio , Carsetti Rita , Mortari Eva Piano , Spanu Teresa , Vento Giovanni
Published: January 2022

Objective The study aimed to report a novel coronavirus disease 2019 (COVID-19)-associated multisystem inflammatory syndrome in children (MIS-C) in a neonate found to have an atypical diffuse thickening in coronary artery walls whose diagnosis required a multi-imaging approach.

Study Design A neonate presented at birth with multiple organ involvement and coronary artery anomalies. A diagnosis of MIS-C associated with COVID-19 was supported by maternal severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection during pregnancy, and by the presence of both immunoglobulin (Ig)-G against SARS-CoV-2 and spike-specific memory B-cells response in the neonatal blood. Other plausible causes of the multiple organ involvement were excluded.

Result At admission, a severe coronary artery dilatation was identified on echocardiography, supporting the diagnosis of the MIS-C Kawasaki-like disease; however, coronary artery internal diameters were found to be normal using cardiac computed tomography angiography. At discharge, comparing the two imaging techniques each other, the correct diagnosis resulted to be an abnormal thickening in coronary arterial walls. These findings suggest that the inflammatory process affecting the coronary arterial wall in MIS-C could result not only in typical coronary artery lesions such as dilatation of the lumen or aneurysms development but also in abnormal thickening of the coronary artery wall.

Conclusion Our case provides an alert for pediatric cardiologists about the complexity to assess coronary artery involvement in MIS-C and raises the question that whether an abnormal vascular remodeling, with normal inner diameters, is to be considered like coronary artery dilatation for risk stratification.

Key Points
Endoscopic Operating Platforms and Advancements
Authors: Sethi Ila , Rosenbluth Amy
Published: January 2022

The first endoscope was created in 1805 by Philip Bozini in Germany. This endoscope was known as “Lichtleiter,” a light guiding instrument. In the 1950s, the first models of fiberoptic endoscopes were introduced. Since then, the technology associated with endoscopic surgery has grown by leaps and bounds. This article aims to explore current operating platforms and emerging technology associated with endoscopic surgery.
Bilateral Optic Neuritis Caused by Meningococcal Meningoencephalitis
Authors: Zellner Herta , Entenmann Andreas , Unterberger Iris , Muigg Armin , Egger Stephan , Kössler Miriam , Zeiner Fiona , Baumann Matthias , Teuchner Barbara , Janjic Tanja , Putz Diana , Zlamy Manuela
Published: January 2022

In this article, we described a case of pathogen-induced bilateral optic neuritis accompanying meningococcal meningoencephalitis in an adolescent male. A 15-year-old boy presented to our emergency room due to progressive severe headache, stiff neck, diffuse extremity pain, fever, and nausea concerning meningoencephalitis. Intravenous ceftriaxone, metamizole, and ondansetron were started immediately. Due to acute autonomic dysregulation and development of petechiae, he was transferred to the pediatric intensive care unit. Next morning, the patient developed severe visual impairment. Investigations revealed elevated C-reactive protein, procalcitonin and leucocyte count, decreased platelet count, and clotting activation. Cerebrospinal fluid (CSF) analysis revealed increased leucocyte count, protein, and decreased glucose concentration with pathological CSF cytology. Brain magnetic resonance imaging revealed an increased contrast enhancement in the optic nerve sheath, consistent with acute bilateral optic neuritis. He was started on high-dose intravenous pulse methylprednisolone therapy. After treatment with ceftriaxone und pulse steroids, the patient was discharged in good condition without any visual sequel.
Peritoneal Dialysis with Rigid Catheters in Children with Acute Kidney Injury: A Single-Centre Experience
Authors: Garg Manasi , V. Lalitha A. , Vasudevan Anil
Published: January 2022

Peritoneal dialysis (PD) is a simple and preferred modality of dialysis for children with acute kidney injury (AKI) in resource poor countries. The aim of the study is to evaluate the utility and safety of acute PD using rigid catheter in critically ill children admitted to pediatric intensive care unit (PICU) with emphasis on short-term patient and renal outcome and complications. In this retrospective study, outcome and complications of PD using rigid catheter were evaluated in 113 critically ill children admitted in PICU of a tertiary care hospital from 2014 to 2019. The most common causes for AKI were sepsis (39.8%), dengue infection (16.8%), and hemolytic uremic syndrome (13.2%). In 113 patients, 122 PD catheters were inserted, and the median duration of PD was 60 (IQR: 36–89) hours. At the initiation of PD, 64 (56.6%) patients were critically ill requiring mechanical ventilation and inotropes, 26 (23%) had disseminated intravascular coagulation, and 42 (37%) had multiorgan dysfunction syndrome. PD was effective and there was a significant improvement in urea and creatinine, and one-third patients (n = 38; 33.6%) had complete renal recovery at the end of PD. Total complications were seen in 67% children but majority of them were metabolic (39.8%). Total catheter related complications were seen in 21.2% and peritonitis was seen in 4.4%. Catheter removal due to complications was required in 8.8% children. Overall, among children on PD, 53.7% survived. Acute PD with rigid catheters can be performed bedside in absence of soft catheters and significant clearance can be obtained without major life-threatening complications.
Hashimoto's Encephalopathy Masquerading as Rapidly Progressive Dementia and Extrapyramidal Failure
Authors: Aladdin Yasser , Shirah Bader
Published: January 2022

Hashimoto's encephalopathy is a rare immune-mediated disorder characterized by subacute encephalopathy with elevated thyroid antibodies. Hashimoto's encephalopathy is also known as steroid-responsive encephalopathy associated with autoimmune thyroiditis. We report a rare presentation of Hashimoto's encephalopathy presenting with acute neuropsychiatric disturbances, rapidly progressive dementia, seizures, and extrapyramidal failure. Neuroimaging revealed multifocal vasculitides of major cerebral vessels that support the autoimmune vasculitic theory as the underlying pathogenesis for Hashimoto's encephalopathy. Unfortunately, permanent irreversible cerebral damage has already ensued before her presentation to our center, which rendered steroid therapy ineffective. Serological testing for Hashimoto's thyroiditis must be in the investigation of all rapidly progressive dementias as early diagnosis and timely management of autoimmune thyroiditis may salvage sizable and eloquent cerebral tissues. The rarity of the condition should not preclude the investigation of Hashimoto's disease even in the presence of normal levels of thyroid hormones. Delayed diagnosis may result in irreversibly catastrophic encephalopathy in patients who once presented with potentially curable dementia.
Recurrent Bilateral Lower Motor Neuron Type of Facial Palsy with Hearing Impairment: Hyperphosphatemic Familial Tumoral Calcinosis
Authors: Gowda Vykuntaraju K. , Raj Anusha , Vamyanmane Dhananjaya K. , Nagarajappa Vani H. , Srinivas Sahana M. , Tirumale Rajalakshmi , Ranganath Jaya , Gaddehosur Chandan , Vishwanathan Gurudatta B.
Published: January 2022

Hyperphosphatemic familial tumoral calcinosis (HFTC) presents with varied neurological manifestations that have been reported in the literature like facial palsy, vision and hearing impairment, stroke, and headache. In this article, we reported a 12-year-old girl child patient with recurrent facial weakness with bilateral hearing impairment and multiple ulcerative lesions on lower limbs and elbows. On examination, she had lower motor neuron (LMN) facial palsy with conductive hearing loss. The investigations showed hyperphosphatemia (9.3 mg/dL) with normal serum calcium (10.4 mg/dL), alkaline phosphatase (147.9 U/L), parathyroid hormone (23.12 pg/mL), and renal function tests. Elevated serum calcium and phosphorus product (96.72 mg2/mL2) and elevated renal tubular reabsorption of phosphate (TMPxGFR) value (9.16) were noted. Skeletal survey showed hyperostosis in the long bone diaphysis, vertebrae, ribs, pelvic bone, skull, and facial bones with narrowing of cranial ostium, characteristically without any peri-articular soft tissue calcifications. An angiogram showed multiple intravascular calcifications. She was managed with a low-phosphate diet, sevelamer, niacinamide, acetazolamide, sucroferric oxyhydroxide to lower serum phosphate level, and topical sodium thiosulfate ectopic cutaneous calcification. Exome sequencing showed novel homozygous inframe deletion of ACG in FGF23 gene exon 3 at c.374_376 delins position (p. Asp125del) in the proband and a mutation in the heterozygous state in the mother and elder sibling, thus confirming a molecular diagnosis of HFTC. Our case had a unique neurological presentation of recurrent bilateral lower motor nerve facial palsy, hearing loss, multiple ectopic cutaneous calcifications without peri-articular deposits, multiple intravascular, intracranial, and vertebral endplate calcification, which has not been reported earlier. The proband showed a novel pathogenic variant suggesting an expanding phenotype of HFTC.
Contiguous-Level Unilateral Cervical Spine Facet Dislocation—A Report of a Less Discussed Subtype
Authors: Das Sunil Kumar , Sekar Arunkumar , Jaidev Srinivas , Patnaik Ashis , Sahu Rabi Narayan
Published: January 2022

Unilateral facet dislocation of subaxial cervical spine trauma is characterized by dislocation of inferior facet of superior vertebra over the superior facet of inferior vertebra. The injury is due to high-velocity trauma and associated with instability of spinal column. Such unilateral facet dislocations occurring at multiple adjacent levels for some reason are not reported or studied frequently. We have reported two cases of multiple-level dislocation of unilateral facets managed in our hospital with a review of available literature. The injury occurs as one side of the motion segment translates and rotates around an intact facet on the contralateral side. The major mechanism of injury is distractive flexion injury with axial rotation component. The injury is associated with instability secondary to loss of the discoligamentous complex. In cases with multiple-level dislocations of unilateral cervical facets, there are multiple mechanisms associated with significant neurological injury and most of them succumb at the site of injury. Only three other cases are available in English language literature. The neurological outcome is invariably poor. Multiple-level facet dislocations of subaxial cervical spine are reported sparsely in literature. We suspect that due to high-velocity nature of these injuries, most of them succumb soon after injury and not often reported. This article reports two cases of contiguous-level unilateral facet dislocation of subaxial cervical spine with associated injuries and the outcomes with review of literature.
Insufficient social support for fathers of children with developmental disorders
Authors: Ishida Shiori , Okuno Hiromi , Igarashi Hisato , Takahashi Hiroko
Published: January 2022

Many parents carry exceptional burdens in childcare, especially while raising children with developmental disabilities (DD). Japanese local governments provide considerable support to mothers and their families, which indicates that such services are in high demand. However, similar assistance for fathers in the context of children with DD may be lacking. This study evaluated the social support status of fathers raising children with DD towards considering increased paternal support. Multiple-choice questionnaires on support for information (6 items), emotion (7 items), evaluation (3 items), and daily living (3 items) were completed by Japanese fathers (n = 85) and mothers (n = 101) of children with DD attending rehabilitation facilities. Regarding information support, fathers answered “spouse” as the main provider for all items, which differed significantly from mothers. For emotional support, fathers significantly more frequently received assistance from their workplace and spouse. Daily living support was also significantly more predominant for fathers in the workplace. Evaluation support sources were comparable between the respondent groups, with “spouse” being most frequently answered by fathers. These findings indicate a deficiency in external resources for fathers and support a need to consider increasing non-spouse resources and social support for fathers in raising children with DD.
Modeling heats of solution for CuNixM(1−x): M = Rh, Sr, and Ir alloys
Authors: Akande T. H. , Matthew-Ojelabi F. , Agunbiade G. S. , Adesakin G. E. , Ojuola T. A. , Fasiku A.
Published: January 2022

So far, many research works have been carried out on the heats of solutions for binary alloy systems, but research studies on ternary heats of solutions are still scarce. The thermodynamic properties of the ternary CuNixM(1−x) system, where M = Rh, Sr, and Ir, were predicted using the concept of the thermodynamic properties of binary systems for the ternary system. The idea of predicting CuNixM(1−x) values was regarded as the calculation of the values of heats of solutions and Gibbs free energy for the ternary alloys. The embedded atom method formalism was used to calculate the parameters for the heats of solutions of binary alloys in reasonable compliance with the available experiment and was extended to the prediction of the thermodynamic properties of ternary alloys. The calculated heats of solutions of the ternary systems Cu–Ni–Rh, Cu–Ni–Sr, and Cu–Ni–Ir are −0.814, 16.840, and −1.504 eV, respectively. It was observed that the heat of solution decreases as the value of x increases with Rh and Sr, while the heat of solution increases as x increases for Ir. The stability order is Cu–Ni–Ir, Cu–Ni–Rh, and Cu–Ni–Sr. The liquidus temperature TL at various values of x = 0.00, 0.25, 0.50, 0.75, and 1.00 for the ternary alloys is presented.
Nanoscale tip positioning with a multi-tip scanning tunneling microscope using topography images
Authors: Leis Arthur , Cherepanov Vasily , Voigtländer Bert , Tautz F. Stefan
Published: January 2022

Multi-tip scanning tunneling microscopy (STM) is a powerful method to perform charge transport measurements at the nanoscale. With four STM tips positioned on the surface of a sample, four-point resistance measurements can be performed in dedicated geometric configurations. Here, we present an alternative to the most often used scanning electron microscope imaging to infer the corresponding tip positions. After the initial coarse positioning is monitored by an optical microscope, STM scanning itself is used to determine the inter-tip distances. A large STM overview scan serves as a reference map. Recognition of the same topographic features in the reference map and in small scale images with the individual tips allows us to identify the tip positions with an accuracy of about 20 nm for a typical tip spacing of ∼1μm. In order to correct for effects such as the non-linearity of the deflection, creep, and hysteresis of the piezoelectric elements of the STM, a careful calibration has to be performed.
The integrated density of states of the 1D discrete Anderson–Bernoulli model at rational energies
Authors: Sánchez-Mendoza Daniel
Published: January 2022

We show that there is a countable dense set of energies at which the integrated density of states of the 1D discrete Anderson–Bernoulli model can be given explicitly and does not depend on the disorder parameter, provided that the latter is above an energy-dependent threshold.
Molecular dynamics study of nanoscale droplets impacting on textured substrates of variable wettability
Authors: Sun Lijun , Pan Jiaxin , Wang Xin , Jing Dengwei
Published: January 2022

The impact of nanodroplets on a solid surface is widely encountered in industrial processes. Understanding the processes that occur when nanodroplets impact a rough surface is of great significance, but the mechanism and dynamics of these processes remain unclear due to the limitations of experimental tools and the shortcomings of most macroscale models. This paper describes molecular dynamics simulations conducted to explore these nanoscale processes. The wettability and solid fraction of the textured substrate and the effects of different impact velocities are investigated. We demonstrate that the maximum spreading time can be described as a power law of the Weber number and that the maximum spreading factor increases with increasing surface wettability. Owing to changes in the attraction between the nanodroplets and the textured substrate, the maximum spreading factor also increases as the solid fraction increases. Based on energy analysis, a theoretical model is proposed for predicting the maximum spreading factor, and this is found to be in good agreement with the simulation results. The results of this study provide useful guidance for predicting the dynamics of nanodroplet impacts.
Visualization and quantification of the stress distribution on epoxy resin through photoelasticity and infrared radiation techniques
Authors: Chen Lu , Zhang Mingyuan , Li Dejian , Li Yingjun
Published: January 2022

To investigate the applicability of infrared thermography as a method for acquiring dynamic stress distribution in epoxy resin, a comparison of infrared radiation thermography with the photoelasticity technique has been made. A series of four-point bending tests of epoxy resin have been performed to evaluate the stress obtained by infrared radiation and illustrate the capabilities and accuracy of the proposed methods. To compare the stress distribution and evolution of epoxy resin detected by two methods, the experimental results show the validity and reliability of infrared radiation thermography in visualizing and quantifying the distribution and evolution characteristics of solid materials. This research was based on two basic tests, the results indicated that infrared radiation thermography is effective in exploring the dynamic distribution and evolution of stress on solid materials. The proposed testing method is effective in exploring the distribution and evolution of stress on different solid materials.
Quasi-hemispherical pit array textured surface for increasing the efficiency of thin-film solar cells
Authors: Chen Le , Fang Bowen , Ke Qinglin , Wangyang Peihua , Hu Kexiang , Zhang Wentao
Published: January 2022

Enhancing light absorption is an important way for solar cells to increase the conversion efficiency. In this paper, we prepared a quasi-hemispherical pit array texture on the glass surface through the micro-fabrication process. Then, silicon thin-film (a-Si:H) solar cells were deposited on the other smooth surface. Pit array textured cells exhibit a higher short-circuit current density and power conversion efficiency than flat devices by ∼7% and 5%, respectively. The reflectance spectrum of textured solar cells is considerably reduced, and the external quantum efficiency is considerably improved in the 300–800 nm wavelength range. Through COMSOL Multiphysics and finite-difference time-domain (FDTD) simulation, three significant effects identify light-trapping characteristics for textured structures: surface reflection reduction, secondary absorption, and light scattering. As a result, the textured surface of the quasi-hemispherical pit array can considerably increase the efficiency of solar cells. Meanwhile, the Lumerical DEVICE software was used to simulate the electrical characteristics of the cell, and the experimental results were theoretically proven.
Arc-extinguishing characteristics of semi-enclosed structures based on theory of positive shock wave reflection
Authors: Chen Yuning , Wang Jufeng , Huang Ping , Wang Yanlei , Zhang Yiyi
Published: January 2022

Lightning current in the process of discharge can cause the potential differences between insulators to rise, hindering the normal operation of the equipment. To reduce the potential difference between insulators during a lightning strike, this study proposes a semi-enclosed structure to limit the rise of potential between insulators. Lightning-induced overvoltage causes the semi-enclosed structure to discharge, forming an arc channel. Because the arc is compressed by the structure, an overpressure-induced shock wave is generated. Positive reflection occurs when the shock wave hits the wall that damages the development of the arc through superposition. By using the theory of positive reflection of shock waves, the overpressure due to a positively reflected wave, generated by an impulse current of 8/20 µs with a peak value of 10 kA, was as high as 4.8 MPa, 48 times the initial pressure. Moreover, a 3D high-current impulse discharge model was established in COMSOL to simulate the process of shock discharge of the structure in the case of a large current. Finally, current-induced shock tests were carried out in the semi-enclosed structure. The results show that the maximum pressure in the semi-enclosed structure was 4.38 MPa at 10 µs and conductivity dropped to zero at 80 µs. In experiments, the amplitude of the impulse current decreased from 9.54 to 5.72 kA, and the current dropped to zero at about 65 µs. The results show that the semi-enclosed structure can extinguish the arc and limit the rise of potential between insulators.
Basis-set correction based on density-functional theory: Rigorous framework for a one-dimensional model
Authors: Traore Diata , Giner Emmanuel , Toulouse Julien
Published: January 2022

We re-examine the recently introduced basis-set correction theory based on density-functional theory, which consists of correcting the basis-set incompleteness error of wave-function methods using a density functional. We use a one-dimensional model Hamiltonian with delta-potential interactions, which has the advantage of making easier to perform a more systematic analysis than for three-dimensional Coulombic systems while keeping the essence of the slow basis convergence problem of wave-function methods. We provide some mathematical details about the theory and propose a new variant of basis-set correction, which has the advantage of being suited to the development of an adapted local-density approximation. We show, indeed, how to develop a local-density approximation for the basis-set correction functional, which is automatically adapted to the basis set employed, without resorting to range-separated density-functional theory as in previous studies, but using instead a finite uniform electron gas whose electron–electron interaction is projected on the basis set. The work puts the basis-set correction theory on firmer ground and provides an interesting strategy for the improvement of this approach.
Radiation-induced instability of a finite-chord Nemtsov membrane
Authors: Labarbe Joris , Kirillov Oleg N.
Published: January 2022

We consider a problem of stability of a membrane of an infinite span and a finite chord length, submerged in a uniform flow of finite depth with free surface. In the shallow water approximation, Nemtsov [“Flutter effect and emission in the region of anomalous and normal Doppler effects,” Radiophys. Quantum Electron. 28(12), 1076–1079 (1985)] has shown that an infinite-chord membrane is susceptible to flutter instability due to the excitation of long gravity waves on the free surface if the velocity of the flow exceeds the phase velocity of the waves and related this phenomenon with the anomalous Doppler effect. In the present work, we derive a full nonlinear eigenvalue problem for an integrodifferential equation for the finite-chord Nemtsov membrane in the finite-depth flow. In the shallow- and deep-water limits, we develop a perturbation theory in the small added mass ratio parameter acting as an effective dissipation to find explicit analytical expressions for the frequencies and the growth rates of the membrane modes coupled to the surface waves. We find an intricate pattern of instability pockets in the parameter space and describe it analytically. The case of an arbitrary depth flow with free surface requires numerical solution of a new non-polynomial nonlinear eigenvalue problem. We propose an original approach combining methods of complex analysis and residue calculus, Galerkin discretization, Newton method, and parallelization techniques implemented in MATLAB to produce high-accuracy stability diagrams within an unprecedented wide range of a system's parameters. We believe that the Nemtsov membrane plays the same paradigmatic role for understanding radiation-induced instabilities as the Lamb oscillator coupled to a string has played for understanding radiation damping.
Unprecedented severe atomic redistribution in germanium induced by MeV self-irradiation
Authors: Tran Tuan T. , Primetzhofer Daniel
Published: January 2022

We present a pronounced unprecedented surface modification of a crystalline Ge layer under ion irradiation with a Ge ion beam at the energy of 2.5 MeV. Samples were covered by a thin SiN-protection layer to protect from sputtering and surface redeposition phenomena. Under the irradiation conditions, the Ge layer did not become porous as observed for other projectiles and lower energies but develops into a severely uneven morphology with characteristic length scales of several hundred nanometers. The observed roughness monotonically increases with the irradiation doses. We show that this phenomenon is caused neither by the surface erosion effect nor by a non-uniform volumetric expansion. Rather, atomic redistribution in the bulk of the material is the major drive for the uneven surface. Furthermore, the deformation of the Ge layer likely occurs to the largest extent after irradiation, as indicated by the very flat interface around the end-of-range region. The observed morphology modification is discussed based on irradiation-induced plastic flow, coupled with a larger contribution of the electronic component in the ion–solid interactions.
Fracture prediction of CFRP laminates subjected to CW laser heating and pre-tensile loads based on ANN
Authors: Wang Jiawei , Lin Chongyu , Feng Guobin , Li Bin , Wu Lixiong , Wei Chenghua , Lv Yuwei , Cheng Jiajun
Published: January 2022

For the application of composite materials in a complex thermal and mechanical environment, we developed a standard artificial neural network (ANN) model for the fracture prediction of carbon fiber-reinforced polymer (CFRP) laminates under continuous wave laser heating and pre-tensile loads. A substantial amount of data was collected through experimentation and from published references, which were converted into 12 800 binary-classification-type input/output data pairs before being used for model training. Different numbers of hidden neurons were evaluated to determine the optimal architecture of the model, while the “early stopping” and “dropout” methods were used to improve its robustness. The trained ANN model functions as a binary classifier that can predict the fracture probability of CFRP laminates after a certain period of laser irradiation. Subsequently, another 14 sets of experimentally collected data were used for ANN model testing. The correct prediction rate of the model reached 86%, which was higher than two other machine learning models (k-nearest neighbors and random forest models) under the same conditions. As the failure behavior of CFRP laminates has a certain degree of randomness, the fracture probabilities predicted by the ANN model have more practical values than the specific fracture times predicted by existing theories. Results indicate that it is feasible to apply the ANN method to predict the failure behavior of composite materials with discrete mechanical properties in complex thermal environments, and this study provides useful guidance for the engineering applications of composite materials in complex thermal and mechanical environments.
Simple evaluation of dynamic disorder effects on exciton transport
Authors: Carreras Abel , Casanova David
Published: January 2022

Exciton transport in molecular materials is usually well described by Fermi’s golden rule within the Condon approximation. However, when collective or molecular vibrations are thermally accessible, dynamic disorder effects have a sizable impact on the predicted exciton transfer rates and need to be considered for quantitative evaluation. In this work, we derive an analytic expression for the distribution of the electronic couplings that gives direct access to averaged quantities without the need to perform explicit calculations for a distribution of structural conformations. The distribution of exciton couplings and transfer rates obtained by this simple model in the study of singlet exciton transfer in the crystal naphthalene are in very good agreement with the data generated from molecular dynamics.
Thermal stability study of TC11 titanium alloy thin component after surface nanocrystallization induced by laser shock processing
Authors: Nie Xiangfan , Tang Yuyuan , Zhao Feifan , Luo Sihai , He Weifeng , Wei Chen , Song Jingdong , Pang Zhicong
Published: January 2022

Laser shock peening (LSP) can induce the compressive residual stress (CRS) on the surface of the material, and surface nanocrystallization can be realized with a nanocrystal layer, thereby significantly improving the high-cycle fatigue performance. However, due to weak material constrain and the high working temperature of thin aero-engine compressor blades, CRS and refined grain structure are more likely to result in stress relaxation and microstructural recovery under thermal stress load, resulting in reducing the anti-fatigue effect of LSP. In this paper, on the basis of the surface nanocrystallization induced by LSP, residual stress and microstructure of TC11 titanium alloy thin components were measured and observed. The residual stress relaxation was characterized and the microstructure evolution was discussed. Also, the thermal stability mechanism of CRS and the nanostructure on the surface were analyzed. The experimental results show that after thermal loads, the CRS was decreased, and the stress relaxation amplitude was increased with an increase in temperature. After annealing at 400 °C, the dislocation density was significantly reduced, but the grain sizes of surface nanostructure did not greatly increase. After annealing at 400 °C for 2 h, the fatigue strength of the LSPed specimen was reduced compared with that before annealing, but it was still increased compared with the original state without LSP, especially under high-power density for multiple LSP treatment. It can be concluded that the surface nanostructure has good stability and effectively retards the initiation of fatigue cracks on the surface, which ensures the effectiveness of LSP under thermal loads.
Genotypic variation of conservative and profligate water use in the vegetative and reproductive stages of canola (
Authors: Luo Tao , Hu Liyong , Zhang Heping
Published: January 2022

Limited water availability is a major constraint to canola (Brassica napus L.) yield in the Mediterranean-type climate region. Selecting and breeding for genotypes with conservative water use characteristics is a promising strategy to improve yield in this environment. Three experiments were conducted to investigate transpiration responses (TR) to vapour pressure deficit (VPD) and progressive soil drying with 8–20 canola genotypes. We used the linear-plateau model to describe TR to elevated VPD and decreased fraction of transpirable soil water (FTSW) and identified the VPD and FTSW thresholds for plant to limit its transpiration. Canola genotypes showed significant variations in both VPD and FTSW thresholds. The genotypes with conservative water use reduced TR at a lower VPD threshold and decreased TR at a higher FTSW threshold than the profligate ones. We found that the conservative genotypes had low VPD and high FTSW thresholds while the profligate ones had high VPD and low FTSW thresholds. This conservative and profligate water use characteristics were consistent during both vegetative and reproductive stages. Furthermore, the relative yield of genotypes under drought conditions was positively related to the FTSW thresholds during the reproductive stage, indicating the better relative yield performance of conservative genotypes in water-limited farming system. We conclude that canola genotypes with lower VPD and higher FTSW thresholds could conserve water and defer water use for reproductive growth while the profligate genotypes can be deployed to take advantage of high rainfall in the high rainfall zone of southern Australia.
Lipoprotein-associated phospholipase A
2
: A paradigm for allosteric regulation by membranes
Authors: Mouchlis Varnavas D. , Hayashi Daiki , Vasquez Alexis M. , Cao Jian , McCammon J. Andrew , Dennis Edward A.
Published: January 2022

Significance

Lp-PLA
2
is a physiologically important human enzyme and an inflammatory biomarker for assessing risk factors associated with cardiovascular diseases. It is associated with low- and high-density lipoproteins in human plasma and acts on the outside of the phospholipid monolayer that coats these particles, in stark contrast to traditional PLA
2
enzymes that act on bilayer membranes. This study addresses the allosteric activation of Lp-PLA
2
by phospholipid monolayers and membranes, its precise selectivity and specificity for particular oxidized and short acyl-chain phospholipid substrates not previously possible. Of particular importance, this work identifies and confirms by site-directed mutagenesis a phospholipid head-group binding pocket distinct from known drug inhibitor binding pockets that informs us about Lp-PLA
2
’s mechanism of action and creates opportunities for additional therapeutic approaches.
Bacillus anthracis
induces NLRP3 inflammasome activation and caspase-8–mediated apoptosis of macrophages to promote lethal anthrax
Authors: Van Hauwermeiren Filip , Van Opdenbosch Nina , Van Gorp Hanne , de Vasconcelos Nathalia , van Loo Geert , Vandenabeele Peter , Kanneganti Thirumala-Devi , Lamkanfi Mohamed
Published: January 2022

Significance

Anthrax is a deadly infection caused by exposure to
Bacillus anthracis
bacteria. Anthrax lethal toxin (LeTx) has long been recognized as a major determinant of lethal anthrax, which paralyzes the host’s immune defenses by killing off macrophages. Despite the importance of macrophage cytotoxicity in anthrax pathogenesis, the signaling pathways underlying cell death of
B. anthracis
-infected macrophages are poorly understood. This study shows that infection with live
B. anthracis
or LeTx intoxication sensitizes macrophages to TNF-dependent NLRP3 inflammasome activation and caspase-8–mediated apoptosis. Moreover, caspase-8–mediated apoptosis is shown to promote anthrax-associated lethality in vivo. Collectively, the study establishes TNF- and RIPK1 kinase activity–dependent NLRP3 inflammasome activation and macrophage apoptosis as key host–pathogen mechanisms in lethal anthrax.
A content-adaptive unstructured grid based regularized CT reconstruction method with a SART-type preconditioned fixed-point proximity algorithm
Authors: Chen Yun , Lu Yao , Ma Xiangyuan , Xu Yuesheng
Published: January 2022

The goal of this study is to develop a new computed tomography (CT) image reconstruction method, aiming at improving the quality of the reconstructed images of existing methods while reducing computational costs. Existing CT reconstruction is modeled by pixel-based piecewise constant approximations of the integral equation that describes the CT projection data acquisition process. Using these approximations imposes a bottleneck model error and results in a discrete system of a large size. We propose to develop a content-adaptive unstructured grid (CAUG) based regularized CT reconstruction method to address these issues. Specifically, we design a CAUG of the image domain to sparsely represent the underlying image, and introduce a CAUG-based piecewise linear approximation of the integral equation by employing a collocation method. We further apply a regularization defined on the CAUG for the resulting ill-posed linear system, which may lead to a sparse linear representation for the underlying solution. The regularized CT reconstruction is formulated as a convex optimization problem, whose objective function consists of a weighted least square norm based fidelity term, a regularization term and a constraint term. Here, the corresponding weighted matrix is derived from the simultaneous algebraic reconstruction technique (SART). We then develop a SART-type preconditioned fixed-point proximity algorithm to solve the optimization problem. Convergence analysis is provided for the resulting iterative algorithm. Numerical experiments demonstrate the superiority of the proposed method over several existing methods in terms of both suppressing noise and reducing computational costs. These methods include the SART without regularization and with the quadratic regularization, the traditional total variation (TV) regularized reconstruction method and the TV superiorized conjugate gradient method on the pixel grid.
Fabrication, modeling, and characterization of soft twisting electrothermal actuators with directly printed oblique heater
Authors: Cao Yang , Dong Jingyan
Published: January 2022

Soft electrothermal actuators have drawn extensive attention in recent years for their promising applications in biomimetic and biomedical areas. Most soft electrothermal actuators reported so far demonstrated uniform bending deformation, due to the deposition based fabrication of the conductive heater layer from nanomaterial-based solutions, which generally provides uniform heating capacity and uniform bending deformation. In this paper, a soft electrothermal actuator that can provide twisting deformation was designed and fabricated. A metallic microfilament heater of the soft twisting actuator was directly printed using electrohydrodynamic (EHD) printing, and embedded between two structural layers, a polyimide film and a polydimethylsiloxane layer, with distinct thermal expansion properties. Assisted by the direct patterning capabilities of EHD printing, a skewed heater pattern was designed and printed. This skewed heater pattern not only produces a skewed parallelogram-shaped temperature field, but also changes the stiffness anisotropy of the actuator, leading to twisting deformation with coupled bending. A theoretical kinematic model was built for the twisting actuator to describe its twisting deformation under different actuation effects. Based on that model, influence of design parameters on the twisting angle and motion trajectory of the twisting actuator were studied and validated by experiments. Finite element analysis was utilized for the thermal and deformation analysis of the actuator. The fabricated twisting actuator was characterized on its heating and twisting performance at different supply voltages. Using three twisting actuators, a soft gripper was designed and fabricated to implement pick-and-place operations of delicate objects.
Improved dielectric properties and energy-storage densities of BaTiO3-doped PVDF composites by heat treatment and surface modification of BaTiO3
Authors: Sang Xiaodong , Li Xingjia , Zhang Dandan , Zhang Xiuli , Wang Huiping , Li Saisai
Published: January 2022

In this paper, the dielectric properties of barium titanate/polyvinylidene fluoride (BT/PVDF) composites are investigated. The doped BT particles were prepared using a simple heat treatment. It was found that 1000 °C was the optimal temperature for the doped BT particles to improve the dielectric properties of the BT/PVDF composites. Furthermore, we also found that the breakdown strength of the BT/PVDF composites could be significantly enhanced when the surface of the doped BT particles were pre-modified with phthalic acid or KH550. In particular, the BT/PVDF composites doped with KH550-modified BT particles had a maximum energy-storage density of 4.08 J cm−3, which is 81.33% higher than that of BT/PVDF composites doped with BT particles and without any treatment. Therefore, we can conclude that heat treatment and surface modification of doped BT particles could become a new approach to enhance the energy-storage performance of BT/PVDF composites, and which has good application prospects in the field of dielectric energy-storage materials.
Quantum dynamics research in India: a perspective
Authors: Dutta Amit , Sengupta Krishnendu
Published: January 2022

Comprehending out-of-equilibrium properties of quantum many-body systems is still an emergent area of recent research. The upsurge in this area is motivated by tremendous progress in experimental studies, the key platforms being ultracold atoms and trapped ion systems. There has been a significant contribution from India to this vibrant field. This special issue which includes both review articles and original research papers highlights some of these contributions.
Improving accuracy of cavitation severity recognition in axial piston pumps by denoising time–frequency images
Authors: Chao Qun , Wei Xiaoliang , Lei Junbo , Tao Jianfeng , Liu Chengliang
Published: January 2022

The vibration signal is a good indicator of cavitation in axial piston pumps. Some vibration-based machine learning methods have been developed for recognizing pump cavitation. However, their fault diagnostic performance is often unsatisfactory in industrial applications due to the sensitivity of the vibration signal to noise. In this paper, we present an intelligent method for recognizing the cavitation severity of an axial piston pump in a noisy environment. First, we adopt short-time Fourier transformation to convert the raw vibration data into spectrograms that act as input images of a modified LeNet-5 convolutional neural network (CNN). Second, we propose a denoising method for the converted spectrograms based on frequency spectrum characteristics. Finally, we verify the proposed method on the dataset from a test rig of a high-speed axial piston pump. The experimental results indicate that the denoising method significantly improves the diagnostic performance of the CNN model in a noisy environment. For example, using the denoising method, the accuracy rate forcavitation recognition increases from 0.52 to 0.92 at a signal-to-noise ratio of 4 dB.
A two-stage method for real-time baseline drift compensation in gas sensors
Authors: Zhang Chao , Wang Wen , Pan Yong , Cheng Lina , Zhai Shoupei , Gao Xu
Published: January 2022

Baseline drift caused by slowly changing environment and other instability factors affects significantly the performance of gas sensors, resulting in reduced accuracy of gas classification and quantification of the electronic nose. In this work, a two-stage method is proposed for real-time sensor baseline drift compensation based on estimation theory and piecewise linear approximation. In the first stage, the linear information from the baseline before exposure is extracted for prediction. The second stage continuously predicts changing linear parameters during exposure by combining temperature change information and time series information, and then the baseline drift is compensated by subtracting the predicted baseline from the real sensor response. The proposed method is compared to three efficient algorithms and the experiments are conducted towards two simulated datasets and two surface acoustic wave sensor datasets. The experimental results prove the effectiveness of the proposed algorithm. Moreover, the proposed method can recover the true response signal under different ambient temperatures in real-time, which can guide the future design of low-power and low-cost rapid detection systems.
A novel ensemble method based on the SBLMD-ANN-MOPSO approach for predicting milling stability regimes
Authors: Mishra Rohit , Singh Bhagat
Published: January 2022

In recent decades, a lot of work has been done to mitigate self-excited vibration effects in milling operations. Still, a robust methodology is yet to be developed that can suggest stability bounds pertaining to higher metal removal rates (MRRs). In the present work, experimentally-acquired acoustic signals in milling operations have been computed using a modified spline-based local mean decomposition technique in order to cite tool chatter features. Further, three artificial neural network training algorithms; resilient propagation, conjugate gradient-based and Levenberg–Marquardt algorithms, and two activation functions; hyperbolic tangent sigmoid and log sigmoid, have been used to train the acquired chatter vibration and MRR data set. Over-fitting or under-fitting issues may arise from the random selection of a number of hidden neurons. The solution to these problems is also proposed in this paper. Among these training algorithms and activation functions, a suitable one has been selected and further invoked to develop prediction models of chatter severity and MRR. Finally, multi-objective particle swarm optimization has been invoked to optimize the developed prediction models to obtain the most favourable range of input parameters pertaining to stable milling with higher productivity.