Delta Peak Research Articles

Phase space of electron- and muon-neutrino and antineutrino scattering off nuclei

We discuss the electron and muon neutrino and antineutrino double-differential cross sections on carbon in the quasielastic as well as in the multinucleon and one pion production channels. By projecting them in the transferred momentum—transferred energy plane and in the neutrino energy—lepton scattering angle plane, as well as by performing simple considerations on the position of the quasielastic and Delta peaks and on their broadening, we explain the surprising dominance of the muon neutrino and antineutrino cross sections over the electron ones in particular kinematical conditions. Published by the American Physical Society 2024

COMPATIBILITY STUDY OF HYDROCARBON RESINS WITH RUBBER COMPOUNDS FOR TIRE APPLICATIONS

ABSTRACT The addition of hydrocarbon resins to rubber compounds has a significant impact on their properties such as wet grip and rolling resistance. These performance characteristics have a strong correlation with the compatibility of the resin with the rubber matrix. Incompatible resins can cause excessive broadening of the damping curve, which results in poor rolling resistance. Compatibility, however, allows maximization of wet grip while minimizing the effect on rolling resistance. Compatibility is promoted by lower resin molecular weight and structural similarity to the polymers being blended. In this study, a method based on the Fox equation has been developed to quantitatively characterize the compatibility between resin and natural rubber (NR), a binary system. The dynamic shear rheometer (DSR), a tool new to the tire industry, is used to investigate the interaction between resin and two rubbers (i.e., a ternary system of NR–butadiene rubber [BR]–resin and solution polymerized styrene–butadiene rubber [SSBR]–butadiene rubber [BR]–resin), with a specific emphasis on resin partitioning among rubber blends. In addition, the DSR is applied to assess the Tg shift and tangent delta peak height, providing insight into the compatibility between rubbers and resin. A curve-fitting model was developed for the SSBR–BR–resin system to depict the relationship between these two parameters and the physical and chemical properties of resins, with the selection of resins featuring different degrees of aromaticity, Tg, and molecular weight. The findings indicated that higher Tg increased aromaticity and that lower molecular weight of the resin resulted in an elevated Tg shift in the blend, while lower molecular weight led to an increase in the tangent delta peak height. Our findings supply insight into the performance of rubber–resin blends and introduce a new screening tool for characterizing these blends in their green state.

Localization, fractality, and ergodicity in a monitored qubit

We study the statistical properties of a single two-level system (qubit) subject to repetitive ancilla-based measurements. This setup is a fundamental minimal model for exploring the intricate interplay between the unitary dynamics of the system and the nonunitary stochasticity introduced by quantum measurements, which is central to the phenomenon of measurement-induced phase transitions. We demonstrate that this “toy model” harbors remarkably rich dynamics, manifesting in the distribution function of the qubit's quantum states in the long-time limit. We uncover a compelling analogy with the phenomenon of Anderson localization, albeit governed by distinct underlying mechanisms. Specifically, the state distribution function of the monitored qubit, parameterized by a single angle on the Bloch sphere, exhibits diverse types of behavior familiar from the theory of Anderson transitions, spanning from complete localization to almost uniform delocalization, with fractality occurring between the two limits. By combining analytical solutions for various special cases with two complementary numerical approaches, we achieve a comprehensive understanding of the structure delineating the “phase diagram” of the model. We categorize and quantify the emergent regimes and identify two distinct phases of the monitored qubit: ergodic and nonergodic. Furthermore, we identify a genuinely localized phase within the nonergodic phase, where the state distribution functions consist of delta peaks, as opposed to the delocalized phase characterized by extended distributions. Identification of these phases and demonstration of transitions between them in a monitored qubit are our main findings. Published by the American Physical Society 2024

IR absorption band of weak H-Bonded systems: Showcasing the signature of the quantum indirect damping within the framework of a new approach using non-Hermitean Hamiltonian formalism

Herein, we investigate the effects of the irreversible action of the medium on the theoretical elucidation of the IR spectrum of weakly H-bonded systems, a prototypical model which provides a rigorous treatment of the relaxation mechanisms impacts on the IR spectral density. The attention will be focused particularly on the effect of indirect damping on the IRυS(X−H⃗) spectrum beyond the harmonic and adiabatic approximations. The ultimate objective of the present investigation is the treatment of the action of the surrounding of the intermonomer modes of H-bonded systems, which must induce a broadening of the Dirac delta peaks, the nature of which, as shown by Maréchal and Witkowski theory, is a Franck–Condon progression. The quantum treatment of the IR absorption band reveals that quantum relaxation of the intermonomer mode of H-bonded complexes could be successfully approached by a non-Hermitian Hamiltonian formalism. Motivated by development of a second method that will be able to validate the first approach, a computationally efficient algorithm was proposed for elucidating the quantum indirect relaxation using Hermitean Hamiltonians. The real eigenvalues, corresponding to different energies of the system are considered to be complex by adjunction of the imaginary parts, which reflects the action of the indirect irreversible action of the medium. These two crude approaches may pave the way for the incorporation of the mechanism of indirect relaxation in more physical and complex situations dealing, particularly, with tunnelling effects in strong H-bonded species, Fermi resonances, and Davydov coupling for cyclic H-bonds dimers beyond the harmonic and adiabatic assumptions.

Efficacy of Sinopharm Vaccine Among Stem Cell Transplant Recipients During Two Peaks of Delta and Omicron variants of COVID-19.

Considering the dearth of research on the complications of Sinopharm coronavirus disease 2019 (COVID-19) vaccine in immunocompromised individuals and the lack of available data on COVID-19 vaccination from Iran. This study aimed to investigate the efficacy of vaccine of Sinopharm COVID-19 vaccine and its complications in bone marrow transplant (BMT) recipients. This was a retrospective cross-sectional study conducted on 250 patients with BMT who were referred to Montaserieh Hospital, Mashhad, Iran. Among them, 53 cases who received at least two doses of Sinopharm COVID-19 vaccine from March to January 2021 were entered in this study. The data were extracted from a student dissertation (Code:4000370). Sinopharm vaccine side effects were reported only in 7.7% of the patients, and shingles was the only serious side effect of the Sinopharm vaccine, which was observed only in one case. The results also revealed that Sinopharm COVID-19 vaccine side effects were not related to age or gender. Infection with the Delta variant of COVID-19 was reported in 7.5% (n=4) and no mortality was reported among them. Vaccine failure was reported in 39.6% of the cases; however, no mortality was reported among patients infected with the Omicron variant of COVID-19. In summary, it seems that Sinopharm COVID-19 vaccine adverse effects were not serious among stem cell transplant recipients. However, it may lead to some severe complications in the population. Vaccine failure against the Delta and Omicron variants of COVID-19 has been reported among more than one-third of BMT patients; however, no mortality was observed among BMT patients infected with the new variants of COVID-19.

P047 Slow Wave Dynamics in Mild Cognitive Impairment compared with Age Matched Controls: A High Density EEG study.

Abstract Introduction Slow wave activity during non-rapid eye movement (NREM) sleep has been linked with memory consolidation in healthy older adults. To date, there has been limited research in mild cognitively impaired populations, particularly looking across the whole brain using high density EEG. We aimed to determine if the dynamics of slow wave activity (delta power) during the first NREM sleep cycle differ between patients with mild cognitive impairment (MCI) and healthy older adults. Methods Participants were assessed for MCI by a panel of neuropsychologists and clinicians. They underwent full polysomnography including high-density EEG (256 electrodes). We computed the delta power (0.5-4.5Hz) for each NREM cycle and slope between sleep onset and the peak of delta in the first NREM sleep cycle (rise-rate) which were compared between groups using t-tests. Results 17 older adults with MCI and 21 older healthy controls were assessed. The mean delta power in the first NREM cycle did not differ between MCI and controls across the whole brain, but the global rise-rate (1/min) of MCI and controls was 0.0015 and 0.0032 respectively (t-value -2.35, p=0.025). Discussion Global slow wave dynamics in the first NREM period appear to be altered in patients with MCI compared with age-matched controls. The gentler slope of rise-rate to the first delta peak in MCI patients than in healthy controls may indicate the dysfunction of sleep homeostasis in MCI patients. Regional slow wave dynamics, ultra-low frequency delta (0.25-1Hz), and associations with sleep dependent memory consolidation will further be explored.

The rates and symptoms of natural and breakthrough infection pre- and post- Covid-19 non-mRNA vaccination at various peaks amongst Iranian healthcare workers

Background/AimsThe aim of this study was to determine the rate of natural and breakthrough infection and related symptoms of Covid-19 amongst Iranian healthcare workers (HCWs) who were vaccinated by different non-mRNA-based vaccines at peak points.MethodsIn this cross-sectional study, the RT-PCR test was performed for a total of 10,581 HCWs suspicious of Covid-19 infection. For each HCW, the frequency of SARS-CoV-2 infection and the time of transmission based on vaccination administration time and schedule were examined during different waves of the pandemic. Based on these findings, the study patients were divided into three groups: natural, natural/breakthrough, and breakthrough.ResultsIn total, 53% of the HCWs were exposed to SARS-CoV-2 infection between 1 and 5 times within two years after the current pandemic, while 20.7% and 32.3% experienced natural and breakthrough SARS-CoV-2 infection, respectively. Only 6% of the breakthrough-infected HCWs had naturally contracted SARS-CoV-2 infection during the initial waves. The highest natural peaks of infection occurred during the interval administration of the first and second dose of the first vaccination series, while the single highest peak of breakthrough infection belonged to the Omicron wave. It occurred simultaneously with the administration of the third vaccination dose. On the other hand, the highest rate of reinfection was observed amongst people who had received the Sinopharm and Bharat vaccines full-doses.ConclusionThis study compared the clinical differences between the two peaks of Omicron and Delta. This study indicates the rates of natural and breakthrough SARS-CoV-2 infections according to vaccination schedules and different waves of the pandemic.

COVID-19 and All-Cause Mortality by Race, Ethnicity, and Age Across Five Periods of the Pandemic in the United States

Racial/ethnic and age disparities in COVID-19 and all-cause mortality during 2020 are well documented, but less is known about their evolution over time. We examine changes in age-specific mortality across five pandemic periods in the United States from March 2020 to December 2022 among four racial/ethnic groups (non-Hispanic White, non-Hispanic Black, Hispanic, and non-Hispanic Asian) for ages 35+. We fit Gompertz models to all-cause and COVID-19 death rates by 5-year age groups and construct age-specific racial/ethnic mortality ratios across an Initial peak (Mar–Aug 2020), Winter peak (Nov 2020–Feb 2021), Delta peak (Aug–Oct 2021), Omicron peak (Nov 2021–Feb 2022), and Endemic period (Mar–Dec 2022). We then compare to all-cause patterns observed in 2019. The steep age gradients in COVID-19 mortality in the Initial and Winter peak shifted during the Delta peak, with substantial increases in mortality at working ages, before gradually returning to an older age pattern in the subsequent periods. We find a disproportionate COVID-19 mortality burden on racial and ethnic minority populations early in the pandemic, which led to an increase in all-cause mortality disparities and a temporary elimination of the Hispanic mortality advantage at certain age groups. Mortality disparities narrowed over time, with racial/ethnic all-cause inequalities during the Endemic period generally returning to pre-pandemic levels. Black and Hispanic populations, however, faced a younger age gradient in all-cause mortality in the Endemic period relative to 2019, with younger Hispanic and Black adults in a slightly disadvantageous position and older Black adults in a slightly advantageous position, relative to before the pandemic.

Repeated High-Intensity Technique Training and Repeated Sprint Training Elicit Similar Adjustment in Physiological Responses But Divergent Perceptual Responses and Combat-Related Performances in Adolescent Taekwondo Matches.

This study investigated the effects of 4 weeks of repeated sprint training (RST) versus repeated high-intensity technique training (RTT) on the physiological responses (ie,blood lactate), mean and peak heart rate, rating of perceived exertion, technical-tactical performance, and time-motion variables during simulated taekwondo combats. Twenty-four taekwondo athletes (18 male and 6 female; age: 16 [1]y) were randomly and equally assigned to RST (10 × 35-m running sprints interspersed by 10-s rest) or RTT (10 × 6-s bandal-tchagui kicking executions interspersed by 10-s rest) groups in addition to their regular training. Both groups performed simulated combats before and after training. Delta lactate and peak heart rate were attenuated following training (P < .001 and P = .03, respectively), with no differences identified between RTT and RST conditions. Rating of perceived exertion decreased after training only in the RTT (P = .002). Time fighting and preparatory activities increased following training (P < .001), with higher values observed following RTT than RST (P < .001). Nonpreparatory time decreased after training (P < .001), with more pronounced reductions observed following RTT when compared to RST (P < .001). The number of single attacks decreased only following RST (P < .001), whereas combined attacks increased only after RTT training (P < .001). Similar adjustments in the physiological responses to combat were observed following 4 weeks of either RST or RTT, but RTT elicited more favorable perceptual responses and combat-related performance. This highlights the importance of specificity of training and its effective transfer to combat.

A survey of ORF8 sequence and immunoinformatics features during alpha, delta, and wild type peaks of the SARS-CoV-2 pandemic in Iran.

The Coronavirus disease 2019 (COVID-19) pandemic influences all around the world. The SARS-CoV-2 ORF8 accessory gene represents multiple functions in virus-host interaction. The current study aimed to compare the ORF8 substitutions and epitope features of these substitutions in the various SARS-CoV-2 outbreaks including delta, alpha, and wild type variants in Iran from 2020 to 2022. In addition, we evaluate B cell, HLA I and II epitopes, by in-silico approach to ORF8 binding site prediction. The samples were collected from patients diagnosed with SARS-CoV-2 infection via a real-time PCR assay. Then, a conventional PCR was carried out for ORF8 mutations analysis and further Sanger sequencing. Possible important alterations in epitope features of the ORF8 were evaluated by epitope mapping. B cell, HLA class I and II epitopes, evaluated by online databases ABCpred, NetMHCpan-4.1, and NetMHCIIpan-3.2, respectively. The current study results could not represent novel variations in seven full-length ORF8 sequences or major ORF8 deletions in 80 evaluated samples. In addition, we could not find any ORF8 A382 during each outbreak of variants. Epitope mapping represents differences between the Alpha and other variants, especially in B cell potential epitopes and HLA I. The immunoinformatic evaluation of ORF8 suggested epitopes represent major differences for the Alpha variant in comparison with other variants. In addition, having mild pathogenesis of the Omicron variant does not seem to be associated with ORF8 alteration by phylogenetic evaluation. Future in-vitro studies for a clear conclusion about the epitope features of ORF8 are required.

Investigation of Clinical Manifestations and Laboratory Findings of COVID-19 During National Peaks of Alpha, Beta, Delta, and Omicron in the Pediatric Emergency Department of Mofid Children's Hospital, Tehran, Iran

Background: The global spread of the coronavirus since 2019 has caused significant concern. Objectives: In this study, we aimed to investigate the clinical manifestations and laboratory findings of children infected with the alpha, beta, delta, and omicron strains. Methods: We included all patients who were referred to Mofid Children's Hospital during the peak of the alpha strain in November 2020, the beta strain in April 2021, the delta strain in August 2021, and the omicron strain in February 2022, corresponding to the national peaks of four SARS-CoV-2 variants of concern (VOC). All patients had a positive nasopharyngeal PCR test and were admitted to the emergency ward. We analyzed the collected data using SPSS software. Results: A total of 649 patients were included in this survey, of whom 58.1% were male. The most and least frequent clinical manifestations were fever and skin presentation, respectively. The mean white blood cell count (WBC) was 8423.9 ± 5427.3. The mean values for C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were 30.14 ± 20.07 and 38 ± 22.6, respectively. There was no significant association between coronavirus type, age, and gender. Gastroenteritis, urinary tract infection, and croup showed a statistically significant positive correlation with delta, beta, and omicron (P-values of &lt; 0.003, 0.000, and 0.000, respectively). Cough was more frequent in patients infected with alpha and beta subtypes, while lymphocyte counts were elevated in patients suffering from delta, omicron, and alpha. C-reactive protein and ESR levels were significantly increased in patients with delta infection, and in patients with omicron infection, CRP levels were significantly elevated. Conclusions: Our study revealed that the different strains of COVID-19, corresponding to the World Health Organization (WHO) peak of VOCs, can cause variable clinical symptoms in children. These findings could be helpful in the diagnosis of COVID-19.

Signatures of spectral crossovers in the short- and long-range spectral correlations of a disordered spin-chain with Kramers degeneracy

We investigate several distinct spectral crossovers amongst various integrable (Poissonian) and quantum-chaotic (Wigner-Dyson) limits of a $1\mathrm{D}$ disordered quantum spin ($\mathrm{S}=1/2$) model, by tuning the relative amplitudes of various Hamiltonian parameters to retain or break relevant unitary and antiunitary symmetries. The spin model consists of an isotropic and deterministic Heisenberg term, a random Ising term, an anisotropic and antisymmetric, but deterministic Dzyaloshinskii-Moriya (DM) term, and a Zeeman coupling to a random, inhomogeneous magnetic field. Since we are specially interested in crossovers involving a Gaussian symplectic ensemble (GSE) limit, we carry out all our calculations with an odd number of lattice sites (spins) that naturally results in eigenspectra with Kramers degeneracies (KD's). The various crossovers (viz., the reentrant Poissonian-to-GSE-to-Poissonian, Poissonian-to-GUE, GSE-to-GUE and the reentrant Poissonian-to-GOE-to-Poissonian crossovers) are investigated via detailed studies of both short-range (nearest-neighbour-spacings distribution, NNSD) and long-range [spectral rigidity ${\mathrm{\ensuremath{\Delta}}}_{3}(L)$ and number variance ${\mathrm{\ensuremath{\Sigma}}}^{2}(L)$ ] spectral correlations, where $L$ is the spectral interval over which the long-range statistic is examined. The short-range studies show excellent agreement with RMT predictions. One of the highlights of this study is the systematic investigation of the consequences of retaining both eigenvalues corresponding to every Kramers doublet, in a crossover involving the GSE limit, and see how it evolves to a limit where the KD is naturally lifted. This is seen most clearly in the NNSD study of the GSE-to-GUE (Gaussian unitary ensemble) transition, achieved by gradually lifting the KD, using the random magnetic field. The NNSD plot in the GSE limit here exhibits a Dirac delta peak at zero splitting and a renormalized GSE hump at finite splitting, whose general analytical form and its asymptotic limit are derived. With an increasing symmetry breaking magnetic field the NNSD shows an interesting, dynamic two-peaked structure that finally converges to the standard GUE lineshape. We explain this trend in terms of a competition between the splittings amongst distinct Kramers doublets (related to unitary symmetries) and the Zeeman-like splittings induced by a breaking of the antiunitary time-reversal symmetry (TRS). This is investigated via the NNSD, the marginal spectral density (MSD) and the densities of states (DOS) for both spin models and RMT crossover matrix models. The first and the final short-range studies involve reentrant Poissonian-to-GOE(GSE)-to-Poissonian crossovers, where the final Poissonian is obtained by a many-body localization of states in the strongly disordered limit, whereas the initial Poissonian regime involve much more delocalized eigenstates. In the long-range spectral correlation studies, we shed light on the extent of agreement between our physical spin systems and RMT predictions. We find that the spin systems depart from the ideal RMT predictions for relatively finite $L\ensuremath{\sim}10\ensuremath{-}15$ at least, for the spectral rigidity and a much smaller $L\ensuremath{\sim}2\ensuremath{-}4$ for the number variance. It is further seen that the departure is usually sooner at the uncorrelated (Poissonian) upper end compared to the correlated (Wigner-Dyson) lower end. We carry out a detailed comparison between the local and the global crossover points, associated with the short-range and the long-range statistics respectively, and find that in most cases they seem to agree reasonably well, but for a few exceptions. Our studies also show that the long-range correlations may serve to distinguish between the two Poissonian limits (nonlocalized and localized) in the reentrant crossovers, which the short-range correlations fail to distinguish.

Rate of True-Positive Findings of COVID-19 Typical Appearance at Chest CT per RSNA Consensus Guidelines in an Increasingly Vaccinated Population.

BackgroundRSNA COVID-19 chest CT consensus guidelines are widely used, but their true positive rate for COVID-19 pneumonia has not been assessed among vaccinated patients.PurposeTo assess true positive rate of RSNA typical chest CT findings of COVID-19 among fully vaccinated subjects with PCR-confirmed COVID-19 infection compared with unvaccinated subjects.Materials and MethodsPatients with COVID Typical chest CT findings and one positive or two negative PCR tests for COVID-19 within 7 days of their chest CT between January 2021 – January 2022 at a quaternary academic medical center were included. True positives were defined as chest CTs interpreted as COVID Typical and PCR-confirmed COVID-19 infection within 7 days. Logistic regression models were constructed to quantify the association between PCR results and vaccination status, vaccination status and COVID-19 variants, and vaccination status and months.Results652 subjects (median age 59, [IQR, 48–72]); 371 [57%] men) with CT scans classified as COVID Typical were included. 483 (74%) were unvaccinated and 169 (26%) were fully vaccinated. The overall true positive rate of COVID Typical CTs was lower among vaccinated versus unvaccinated (70/169 [41%; 95% CI: 34, 49%] vs 352/483 [73%; 69, 77%]; OR (95% CI): 3.8 (2.6, 5.5); P < .001). Unvaccinated subjects were more likely to have true positive CTs compared with fully vaccinated subjects during the peaks of COVID-19 variants Alpha (OR, 16 [95% CI: 6.1, 42]; P < .001) and Delta (OR, 8.3 [95% CI: 4.2, 16]; P < .001), but no statistical differences were found during the peak of Omicron variant (OR, 1.7 [95% CI: 0.27, 11]; P = .56)ConclusionFully vaccinated subjects with confirmed COVID-19 breakthrough infections had lower true positive rates of COVID Typical chest CT findings.

Automatic detection of subviral particles in fluorescence microscopy images of Marburg virus infected cells using a convolutional neural network

Abstract In collaboration with the Institute of Virology at the University of Marburg, a tracking algorithm has been developed in recent years. Thereby, for the tracking of subviral particles and their intracellular transport through the cell, the detection of these particles is the first major step. In this work a deep-learning based approach for automatic processing of fluorescence video sequences of virus infected cells is presented. The focus of this work was to generate synthetic data for training neuronal networks and to represent a particle using only a single delta peak. It was shown that a simple convolutional network is able to predict the particle positions with an almost identical accuracy as the algorithm developed by Kienzle, Rausch and colleagues [1-3], and that even a small dataset is sufficient for that purpose.

A Deep Learning Approach in Scalable High Efficiency Video Coding for Fast Coding Unit Size Decision

The High Efficiency Video Coding (HEVC) with scalable extension known as SHVC allows encoding the same video with different resolutions in a single bitstream. However, this process increases the encoding complexity. The complexity is increased mainly due to the motion estimation process and the Rate-Distortion Optimization (RDO) search process. The Test Zonal (TZ) algorithm with fast search patterns helps to accelerate the motion estimation process. However, the search patterns may get trapped to local minima, leading to inaccurate motion vectors. Moreover, the RDO search process used to determine the Coding Unit (CU) size increases the complexity. We proposed the Horizontal Subsampling Motion Estimation (HSME) method to find the accurate motion vectors with reduced complexity. The experimental results prove that the HSME method saves the encoding time by 53.03% with a 6.45% increase in Bjøntegaard delta bit rate and 0.28 dB loss in Bjøntegaard Delta Peak Signal-to-Noise Ratio (BD-PSNR) compared to standard SHM-12.1. In addition, we designed the Early Terminated Long- and Short-Term Memory (ET-LSTM) network that predicts the CU partition by taking the output features of the Early Terminated Convolutional Neural Network (ET-CNN). The ET-CNN learns the CU partitions from the residual Coding Tree Unit (CTU) using the deep learning approach. Our proposed method (HSME + ET-CNN + ET-LSTM) achieves 53% savings in encoding time, which is significantly higher than state-of-the-art methods.

Development and Characterization of Fully Renewable and Biodegradable Polyhydroxyalkanoate Blends with Improved Thermoformability.

Poly(3-hydroxybutyrate-co-3-valerate) (PHBV), being one of the most studied and commercially available polyhydroxyalkanoates (PHAs), presents an intrinsic brittleness and narrow processing window that currently hinders its use in several plastic applications. The aim of this study was to develop a biodegradable PHA-based blend by combining PHBV with poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), another copolyester of the PHA family that shows a more ductile behavior. Blends of PHBV with 20% wt., 30% wt., and 40% wt. of PHBH were obtained by melt mixing, processed by cast extrusion in the form of films, and characterized in terms of their morphology, crystallization behavior, thermal stability, mechanical properties, and thermoformability. Full miscibility of both biopolymers was observed in the amorphous phase due to the presence of a single delta peak, ranging from 4.5 °C to 13.7 °C. Moreover, the incorporation of PHBH hindered the crystallization process of PHBV by decreasing the spherulite growth rate from 1.0 µm/min to 0.3 µm/min. However, for the entire composition range studied, the high brittleness of the resulting materials remained since the presence of PHBH did not prevent the PHBV crystalline phase from governing the mechanical behavior of the blend. Interestingly, the addition of PHBH greatly improved the thermoformability by widening the processing window of PHBV by 7 s, as a result of the increase in the melt strength of the blends even for the lowest PHBH content.

COVID-19-related thrombotic complications experience before and during delta wave.

ObjectiveHypercoagulability and thrombotic complications seen in SARS-CoV-2 patients, as well as the associated pathophysiology, have been reported extensively. However, there is limited information regarding the factors related to this phenomenon and its association with the COVID-19 delta variant.MethodsA retrospective review including patients admitted to a tertiary center with a COVID-19 positive test and at least one acute thrombotic event confirmed by imaging between June 2020 and August 2021 was performed. We compared the rates of thrombotic events in patients with COVID-19 before and during the Delta peak. We also analyzed the association of the thrombotic complications with demographic characteristics, comorbidities, anticoagulation strategies, and prothrombotic markers while describing other complications secondary to COVID-19 infection.ResultsOut of 964 patients admitted with COVID-19 diagnosis, 26.5% (n=256) had a thrombotic event evidenced by ultrasound (US) or computerized tomography (CT) scan. Venous thromboembolism was found in 60% (n=153), arterial thrombosis in 23% (n=60), and both venous and arterial thromboses in 17% (n=17) of the study cohort. Of all patients, 94% were not vaccinated. Delta variant wave patients (DW) had thrombotic episodes in 34.7% (n=50/144) of cases compared to 25% (n=206/820) of non-Delta wave (NDW) patients, posing an estimated risk 1.36 times higher in patients infected with COVID-19 during the DW than NDW. Overall, DW subjects were significantly younger (p<0.001) with lower BMI (p=0.021) compared to NDW patients. Statistical analyses showed African American patients were more likely to have arterial thrombosis compared to the other groups when testing positive for COVID-19 (OR: 1.78 [CI: 1.04 – 3.05], p=0.035), whereas immunosuppressed patients had less risk of arterial thrombosis (OR: 0.38 [CI: 0.15 – 0.96], p=0.042). Female gender (OR: 2.15 [CI: 1.20 – 3.85]. p=0.009) and patients with active malignancy (OR: 5.99 [CI: 2.14 – 16.78]. p=0.001) had an increased risk of having multiple thrombotic events at different locations secondary to COVID-19.ConclusionCOVID-19 infection is associated with elevated rates of thrombotic complications and an especially higher risk in patients infected during the Delta variant peak. We highlight the importance of vaccination and the development of new anticoagulation strategies for COVID-19 patients with additional hypercoagulable risk factors to prevent thrombotic complications caused by this disease.

Viscoelastic and Properties of Amphiphilic Chitin in Plasticised Polylactic Acid/Starch Biocomposite.

The enhancement of the PLA thermomechanical properties is significant due to its suitability as a replacement for primary synthetic polymer use in diverse industrial production. The amphiphilic chitin was used as a compatibilizer in PLA/starch biocomposite. The properties of plasticised polylactic acid blended with starch, and amphiphilic chitin was studied for enhanced thermomechanical and viscoelastic properties. Chitin was modified using acetylated substitution reaction and blended with plasticised PLA/starch biocomposite. The biocomposite was prepared with combined compression and melt extrusion techniques. The biocomposite’s thermomechanical, thermal, mechanical, and morphological properties were studied using dynamic mechanical analysis, TGA-DSC, tensile test, and scanning electron microscopy. The storage and loss modulus were significantly enhanced with increased amphiphilic chitin content. Similarly, the single peak of tan delta showed good miscibility of the polymeric blend. Additionally, the modulus increases with frequency change from 1 Hz to 10 Hz. The thermal stability of the biocomposite was observed to be lower than the neat PLA. The tensile properties of the biocomposite increased significantly more than the neat PLA, with P4S4C having the highest tensile strength and modulus of 87 MPa and 7600 MPa. The SEM images show good miscibility with no significant void in the fractured surface. The viscoelastic properties of PLA were enhanced considerably with plasticizer and amphiphilic chitin with improved biodegradability. The properties of the biocomposite can be adapted for various industrial applications.

In Vivo Corneal Biomechanical Properties in a Selected Chinese Population, Measured Using the Corneal Visualization Scheimpflug Technology.

Purpose: To evaluate the repeatability and reproducibility of recalculated dynamic corneal response (DCR) parameters and the biomechanical-compensated intraocular pressure (bIOP) derived from the Corneal Visualization Scheimpflug Technology (Corvis ST), as well as to study the variations of DCR parameters and their relationship with demographic, and ocular characteristics. Methods: A total of 544 healthy subjects were recruited in this study and a series of ophthalmological examinations were performed on their right eyes. Three repeated measurements were obtained at 3-min intervals for 291 of the participants to ensure repeatability. A sum of 100 participants was examined twice within 2-h intervals using two different Corvis ST in the reproducibility study. The repeatability and reproducibility of 37 parameters, including 36 DCR parameters and bIOP, were assessed by the coefficient of repeatability (CR), coefficient of variation (CV), intraclass correlation coefficient (ICC), and within-subject standard deviation (sw). Pearson’s correlation coefficients and stepwise multivariate linear regression models were performed to investigate whether the DCR parameters were related to demographic and ocular characteristics. Results: Of all the 37 parameters, 34 showed excellent (ICC ≥0.90) or good (ICC ≥0.75) repeatability while 27 of the 37 parameters showed excellent (ICC ≥0.90) or good (ICC ≥0.75) reproducibility. In particular, a CV of less than 20% was found for all DCR parameters and bIOP. A fraction of 14 out of 36 DCR parameters was selected for correlation analysis, based on measurement reliability and clinical relevance in referring to previous literature. Age was negatively associated with the Highest concavity delta arc length (HCdArcL) and peak distance (PD) but it positively correlated with the Whole Eye Movement Max Length (WEMML). Intraocular pressure (IOP) and central corneal thickness (CCT) were negatively associated with the deformation amplitude ratio (DARM) [1 mm], A1 Velocity (A1V), and PD, while positively related to the stiffness parameter at applanation 1 (SP-A1). The bIOP was negatively associated with A1V but positively associated with A2 Velocity (A2V). The anterior chamber volume (ACV) was negatively associated with the pachy slope (PS), WEMML, and SP-A1. Conclusion. The Corvis ST showed good precision for the repeatability and reproducibility of 36 DCR parameters and bIOP parameters in healthy eyes. The IOP, CCT, bIOP, Km, and ACV significantly influenced the DCR parameters of the eyes.

Overnight Delta Dynamics Associated with Daytime Psychomotor Performance in Adults with Insomnia and Healthy Controls.

PurposeSleep is vital to cognition, yet underlying mechanisms remain unclear. Although sleep duration and continuity are two well-established contributors, additional factors—including homeostatic sleep drive processes—may also underlie cognition-related sleep restoration. This study investigates the relative contributions of sleep EEG factors to psychomotor functioning in adults with insomnia and healthy controls (HC) to identify the most significant sleep factors supporting psychomotor functioning.Materials and MethodsAdults with insomnia (n = 37) and HC (n = 39) completed 3 nights of polysomnography and a complex psychomotor task (switching attention task; SAT). Univariate correlations identified the most significant predictors (traditional PSG, spectral EEG, initial delta peak, and overnight delta decline) of SAT performance, which were then entered into multivariable linear regressions examining whether predictors remained significant after accounting for shortened/fragmented sleep and whether relationships differed across groups.ResultsIn addition to greater wake after sleep onset (WASO; r = 0.33), a slower overnight delta decline (r = 0.50) and a lower initial delta peak (r = −0.38) were the most significant predictors of poorer SAT performance. Both overnight delta decline (F(7, 68) = 12.52, p < 0.001) and initial delta peak (F(7, 68) = 7.85, p = 0.007) remained significant predictors after controlling for demographics, total sleep time, and WASO. Relationships were analogous across subject groups.ConclusionFindings suggest that, in addition to sleep duration and continuity, processes related to recovery from and dissipation of homeostatic sleep drive may support psychomotor performance and broadly support daytime functioning in individuals with and without insomnia. Future research may examine overnight delta dynamics as transdiagnostic processes supporting cognition-related sleep restoration across a range of clinical populations.