Search

Abstract Laser plasma-based accelerators provide an excellent source of collimated, bright, and adequately coherent betatron-type x-ray pulses with potential applications in science and industry. So far the laser plasma-based betatron radiation has been described within the concept of classical Liénard–Wiechert potentials incorporated in particle-in-cell simulations, a computing power-demanding approach, especially for the case of multi-petawatt lasers. In this work, we describe the laser plasma-based generation of betatron radiation at the most fundamental level of quantum mechanics. In our approach, photon emission from the relativistic electrons in the plasma bubble is described within a nonlinear quantum electrodynamics (QED) framework. The reported QED-based betatron radiation results are in excellent agreement with similar results using Liénard–Wiechert potentials, as well as in very good agreement with betatron radiation measurements, obtained with multi-10-TW lasers interacting with He and multielectron N $$_2$$ 2 gas targets. Furthermore, our QED approach results in a dramatic reduction of the computational runtime demands, making it a favorable tool for designing betatron radiation experiments, especially in multi-petawatt laser facilities.

Abstract Nanowire array targets exhibit high optical absorption when interacting with short, intense laser pulses. This leads to an increased yield in the production of accelerated particles for a variety of applications. However, these interactions are sensitive to the laser prepulse and could be significantly affected. Here, we show that an array of aligned nanowires is imploded when irradiated by an Amplified Spontaneous Emission pedestal of a $$1\,\text{PW}$$ 1 PW laser with an intensity on the order of $$10^{11}\, \mathrm {W \, cm^{-2}}$$ 10 11 W cm - 2 . Using radiation hydrodynamics simulations, we demonstrate that the electron density profile is radially compressed at the tip by the rocket-like propulsion of the ablated plasma. The mass density compression increases up to $$2.9\times$$ 2.9 × when a more dense nanowire array is used. This is due to the ablation pressure from the neighboring nanowires. These findings offer valuable information for selecting an appropriate target design for experiments aimed at enhancing production of accelerated particles.

Small fiber neuropathy (SFN) is a relatively common, but largely understudied neurological syndrome which has affected the lives of many globally. The common symptoms of SFN include pain, dysesthesia, and autonomic dysfunction, which are caused by damage to small nerve fibers. Due to its heterogeneous nature, SFN causes a multitude of symptoms which makes the disease and its subtypes difficult to diagnose. Furthermore, as the pathophysiology of SFN remains largely enigmatic, no cause is found in around 50% of the cases and these are classified as idiopathic SFN (iSFN). The difficult task of diagnosing SFN, and the even more elusive feat of hunting for the underlying etiology, demands accurate, precise, preferably noninvasive, and affordable tools, or a combination of them. Accordingly, appropriate biomarkers for SFN are needed to stratify patients and develop cause-centered treatments in addition to symptomatic treatments. As peripheral axons grow and repair, identifying underlying causes of SFN and intervening early may spur axonal regeneration in young patients, which can greatly improve their symptoms and improve quality of life. This narrative review aims to objectively highlight functional, histological, and molecular biomarkers to aid clinicians in discerning the diagnostic tests they should use to diagnose, confirm and determine the etiology of SFN. The strengths and limitations of each potential biomarker will be discussed. Clearer diagnostic criteria, guidelines, and work-up for SFN are required for clinicians to better identify the disease in patients presenting with non-specific symptoms.

Intracranial stenosis is prevalent among Asians and constitutes a common cause of cerebral ischemia. While the best medical therapy carries stroke recurrence rates in excess of 10% per year, trials with intracranial stenting have been associated with unacceptable peri-procedural ischemic events. Cerebral ischemic events are strongly related to the severity of intracranial stenosis, which is high in patients with severe intracranial stenosis with poor vasodilatory reserve. Enhanced External Counter Pulsation (EECP) therapy is known to improve myocardial perfusion by facilitating the development of collateral blood vessels in the heart. In this randomized clinical trial, we evaluate whether EECP therapy may be useful in patients with severe stenosis of intracranial internal carotid (ICA) or middle cerebral artery (MCA). The review of literature, methods of evaluation, status of currently used therapeutic approaches, and trial protocol have been presented.Clinical trial registrationClinicalTrials.gov, Identifier: NCT03921827.

IntroductionWhite matter hyperintensities (WMHs) have been observed with greater frequency in patients with migraine and are thought to be associated with impaired cognition and function. The relationship between WMHs and right-to-left shunt (RLS) in migraine patients is unknown. We performed a systematic review to determine if there is an association between RLS and WMHs in patients with migraine.MethodsA systematic search of the literature was performed in PubMed and Embase using a suitable keyword search strategy from inception up to 16th June 2021. All studies that included patients with migraine and studied RLS and WMHs were included.ResultsA total of 8 non-randomized observational studies comprising 1125 patients with migraine were included; 576 had an RLS, compared to 549 patients with no RLS. The mean age of the study populations ranged from 28.4 to 43 years, while the average duration from migraine diagnosis ranged from 5.1 to 19 years. The proportion of female to male patients was consistently higher in all studies (60.0–94.4%). Amongst migraine patients with RLS, 338 patients (58.7%) had WMHs. In contrast, 256 (46.6%) of migraine patients without RLS had WMHs. RLS was significantly associated with the presence of WMHs in migraine patients (OR: 1.56, 95% CI: 1.05–2.34, p = 0.03).ConclusionIn migraine patients, RLS was significantly associated with the presence of WMHs. Longitudinal studies are warranted to establish RLS as a risk factor for WMHs in patients with migraine, and to establish the significance of these changes.

Abstract Background and purpose COVID-19 pandemic led to wide-spread use of face-masks, respirators and other personal protective equipment (PPE) by healthcare workers. Various symptoms attributed to the use of PPE are believed to be, at least in part, due to elevated carbon-dioxide (CO2) levels. We evaluated concentrations of CO2 under various PPE. Methods In a prospective observational study on healthy volunteers, CO2 levels were measured during regular breathing while donning 1) no mask, 2) JustAir® powered air purifying respirator (PAPR), 3) KN95 respirator, and 4) valved-respirator. Serial CO2 measurements were taken with a nasal canula at a frequency of 1-Hz for 15-min for each PPE configuration to evaluate whether National Institute for Occupational Safety and Health (NIOSH) limits were breached. Results The study included 11 healthy volunteers, median age 32 years (range 16–54) and 6 (55%) men. Percent mean (SD) changes in CO2 values for no mask, JustAir® PAPR, KN95 respirator and valve respirator were 0.26 (0.12), 0.59 (0.097), 2.6 (0.14) and 2.4 (0.59), respectively. Use of face masks (KN95 and valved-respirator) resulted in significant increases in CO2 concentrations, which exceeded the 8-h NIOSH exposure threshold limit value-weighted average (TLV-TWA). However, the increases in CO2 concentrations did not breach short-term (15-min) limits. Importantly, these levels were considerably lower than the long-term (8-h) NIOSH limits during donning JustAir® PAPR. There was a statistically significant difference between all pairs (p

Plasmodium vivax is the most widespread and difficult to treat cause of human malaria. The development of vaccines against the blood stages of P. vivax remains a key objective for the control and elimination of vivax malaria. Erythrocyte binding-like (EBL) protein family members such as Duffy binding protein (PvDBP) are of critical importance to erythrocyte invasion and have been the major target for vivax malaria vaccine development. In this study, we focus on another member of EBL protein family, P. vivax erythrocyte binding protein (PvEBP). PvEBP was first identified in Cambodian (C127) field isolates and has subsequently been showed its preferences for binding reticulocytes which is directly inhibited by antibodies. We analysed PvEBP sequence from 316 vivax clinical isolates from eight countries including China (n = 4), Ethiopia (n = 24), Malaysia (n = 53), Myanmar (n = 10), Papua New Guinea (n = 16), Republic of Korea (n = 10), Thailand (n = 174), and Vietnam (n = 25). PvEBP gene exhibited four different phenotypic clusters based on the insertion/deletion (indels) variation. PvEBP-RII (179-479 aa.) showed highest polymorphism similar to other EBL family proteins in various Plasmodium species. Whereas even though PvEBP-RIII-V (480-690 aa.) was the most conserved domain, that showed strong neutral selection pressure for gene purifying with significant population expansion. Antigenicity of both of PvEBP-RII (16.1%) and PvEBP-RIII-V (21.5%) domains were comparatively lower than other P. vivax antigen which expected antigens associated with merozoite invasion. Total IgG recognition level of PvEBP-RII was stronger than PvEBP-RIII-V domain, whereas total IgG inducing level was stronger in PvEBP-RIII-V domain. These results suggest that PvEBP-RII is mainly recognized by natural IgG for innate protection, whereas PvEBP-RIII-V stimulates IgG production activity by B-cell for acquired immunity. Overall, the low antigenicity of both regions in patients with vivax malaria likely reflects genetic polymorphism for strong positive selection in PvEBP-RII and purifying selection in PvEBP-RIII-V domain. These observations pose challenging questions to the selection of EBP and point out the importance of immune pressure and polymorphism required for inclusion of PvEBP as a vaccine candidate.

Conservation and management strategies for endangered and threatened species require accurate estimates of demographic parameters such as age and growth. The whale shark, Rhincodon typus, is the largest fish in the world and is highly valued in the eco-tourism sector. Despite conservation concerns and advances in our understanding of their life history, basic demographic parameters for growth, longevity and mortality are of questionable accuracy; previous growth studies could not agree whether the vertebral growth bands were formed annually or biannually. Here, we provide the first validation of the annual formation of growth bands within the vertebrae of the whale shark using bomb radiocarbon assays. Ages of up to 50 years were estimated from sectioned vertebrae of sharks collected in Taiwan and Pakistan. There was no cessation of the formation of growth bands in the vertebrae of older sharks and our study provides the oldest observed longevity for this species. Initial estimates of growth (k = 0.01–0.12) and natural mortality rates (M = 0.09–0.14) are consistent with those expected of long-lived sharks, which highlights their sensitivity to fishing pressure and conservation concerns.

The emergence of a new era reaching beyond current state-of-the-art ultrashort and ultraintense laser technology has been enabled by the approval of around € 850 million worth of structural funds in 2011–2012 by the European Commission for the installation of Extreme Light Infrastructure (ELI). The ELI project consists of three pillars being built in the Czech Republic, Hungary, and Romania. This challenging proposal is based on recent technical progress allowing ultraintense laser fields in which intensities will soon be reaching as high as I0 ∼ 1023 W cm−2. This tremendous technological advance has been brought about by the invention of chirped pulse amplification by Mourou and Strickland. Romania is hosting the ELI for Nuclear Physics (ELI-NP) pillar in Măgurele near Bucharest. The new facility, currently under construction, is intended to serve the broad national, European, and international scientific community. Its mission covers scientific research at the frontier of knowledge involving two domains. The first is laser-driven experiments related to NP, strong-field quantum electrodynamics, and associated vacuum effects. The second research domain is based on the establishment of a Compton-backscattering-based, high-brilliance, and intense γ beam with Eγ ≲ 19.5 MeV, which represents a merger between laser and accelerator technology. This system will allow the investigation of the nuclear structure of selected isotopes and nuclear reactions of relevance, for example, to astrophysics with hitherto unprecedented resolution and accuracy. In addition to fundamental themes, a large number of applications with significant societal impact will be developed. The implementation of the project started in January 2013 and is spearheaded by the ELI-NP/Horia Hulubei National Institute for Physics and Nuclear Engineering (IFIN-HH). Experiments will begin in early 2020.

Electron transport in a nanowire exhibits a distinct behavior following the irradiation of intense laser pulse. Using particle-in-cell simulation, we observe a large-amplitude particle-driven wakefield excitation followed by electron acceleration in the solid density. Besides, we observed the quiver of the electrons across the nanowire under the action of the surrounding laser electric field facilitating deeper wakefield propagation in the nanowire with 2.5× energy gain over a flat target. These results open insights into the laser-energy coupling with nanostructure targets and radiation sources, and motivate the wakefield acceleration in solid density plasma.

To better characterize the increase in lipoprotein lipase (LPL) translation by hypothyroidism, adipocytes were prepared from control and hypothyroid rats. Whereas LPL synthesis was higher in hypothyroid adipocytes, with no change in mRNA levels, there was no increase in hormone-sensitive lipase (HSL) synthesis. To determine whether a transacting translation regulatory factor was present, a cytoplasmic fraction was prepared from control and hypothyroid adipocytes, and added to an in vitro translation system containing the hLPL mRNA. The hypothyroid cell fraction from adipose and heart yielded an increase in LPL translation, when compared to control extracts. Further experiments determined that the control adipocyte extract contained a translation-inhibitory factor that was 8-fold lower in activity in the hypothyroid extract. Using different LPL mRNA constructs in the in vitro translation reaction, the region that controlled translation was localized to nucleotides 1599 to 1638 (proximal 3' untranslated region (UTR)). To confirm the presence of a transacting factor, a sense RNA strand corresponding to this region was added to the in vitro translation reaction. This sense strand competed for the transacting factor in the control cell extract, yet had no effect on the hypothyroid cell extract. Thus, there is a translation repressor factor in the cytoplasm of rat adipocytes, and this factor is greatly reduced in activity in hypothyroid rat adipocytes. Because a similar mechanism of LPL regulation occurs in response to epinephrine, the absence of the translation repressor may be a mechanism for the loss of sensitivity of hypothyroid cells for catecholamines.

Lipoprotein lipase (LPL) is a key enzyme in lipid metabolism and is found predominantly in adipose tissue and muscle. We examined the mechanism of regulation of LPL in muscles composed of different fiber types (soleus, extensor digitorum longus, and heart) in fed, fasted, and hypothyroid rats. In all muscles, the detergent-extractable (EXT) fraction represented approximately 95% of total LPL activity and mass. LPL activity was similar in the heparin-releasable (HR) fractions of heart and soleus (predominantly type I fibers), while in the EXT fraction LPL activity in soleus was 418 +/- 48 nEq/min per g, and in heart was 272 +/- 30 nEq/min per g (P < 0.05). However, LPL activity in extensor digitorum longus (EDL, predominantly type II fibers) was considerably lower (7.9 +/- 0.8 nEq/min per g in EXT, P < 0.0001 versus heart and soleus). LPL immunoreactive mass followed a pattern similar to LPL activity. LPL mRNA levels were quantitated by both Northern blotting and reverse transcriptase-polymerase chain reaction (RT-PCR), and were approximately equal in heart and soleus, and 5-fold lower in EDL. In response to feeding, LPL activity, mass, and mRNA levels in heart were 30% to 50% lower than in fasted rat heart, although feeding had no effect on soleus or EDL. In hypothyroid animals, muscle LPL activity was increased by 3- to 4-fold in the HR (but not EXT) fractions of heart and soleus (P < 0.05), with no change in LPL mass or mRNA. Thus, muscles with oxidative, type I fibers expressed higher levels of LPL mRNA than muscles containing glycolytic, type II fibers.(ABSTRACT TRUNCATED AT 250 WORDS)

Hormone-sensitive lipase (HSL) mediates the lipolysis of triacylglycerol from mammalian adipocytes, resulting in the release of non-esterified fatty acids and glycerol. Although numerous studies have examined the hormonal regulation of HSL, the measurement of HSL mRNA levels in response to hormonal regulators has not been studied. This study was designed to determine the effects of epinephrine, growth hormone, glucagon, and dexamethasone on HSL expression by measuring HSL mRNA levels and glycerol release in primary cultures of rat adipocytes. Exposure of adipocytes to epinephrine at 10(-7) M and 10(-5) M for 4 h resulted in an increase in medium glycerol (209 +/- 46%, and 284 +/- 58% of control, P < 0.001, respectively). However, no change in HSL mRNA levels occurred due to the epinephrine treatment. Similarly, the peptides glucagon (10(-7) M and 10(-5) M for 4 h) and growth hormone (100 ng/ml for 24 h) resulted in increased medium glycerol and had no effect on HSL mRNA levels in adipocytes. Dexamethasone was added to adipocyte cultures for 4 and 24 h, and resulted in a dose-dependent increase of medium glycerol (102 +/- 8%, 138 +/- 8% (P < 0.001), and 168 +/- 24% (P < 0.001) for 10(-8) M, 10(-7) M, and 10(-6) M, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Background: Although the prevalence of extrahepatic manifestations of chronic hepatitis C virus (HCV) infection has been reported from Western countries, their prevalence in East Asian countries is not well known., Aim: To perform a systematic review to quantify the prevalence of selected extrahepatic manifestations of HCV among patients from East Asia., Methods: Medline, CINAHL, EMBASE, Cochrane and country-specific databases were reviewed according to standard guidelines for meta-analyses. Only articles with patients from East Asian countries were included., Results: After review, 34 articles were selected (Japan = 9; China = 5, Korea = 3, Taiwan = 16, multiple countries = 1) with 646 228 subjects, 66 436 with HCV. Mean age for HCV-infected patients was 56 years (range 41-72 years), 50% were male (range 26%-73%). The pooled prevalence of type 2 diabetes in East Asian HCV patients was 19.0% (95% confidence interval 15.6%-22.9%) (n = 19 studies) with an increased risk when compared to non-HCV: odds ratio (OR) 1.58 (1.28-1.94). The prevalence of chronic kidney disease in HCV was 9.2% (5.0%-16.2%) (n = 7 studies), also with a significantly increased risk: OR=1.98 (1.41-2.77). Pooled prevalence of cardiovascular disease in HCV was 8.6% (3.5%-19.9%) (n = 6 studies), also with an increased risk: OR = 1.55 (1.21-1.98). The prevalence of lichen planus in HCV was 8.9% (3.6%-20.6%) (n = 6 studies) while the prevalence of rheumatoid arthritis was 4.5% (0.6%-25.7%) (n = 4 studies)., Conclusions: These data show increased risk of developing extrahepatic manifestations in East Asian patients with HCV. Both hepatic and extrahepatic manifestations of the infection should be used to accurately determine the total burden of the disease in the region., (© 2019 John Wiley & Sons Ltd.)