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The rapid development of ultrafast ultraintense laser technology continues to create opportunities for studying strong-field physics under extreme conditions. However, accurate determination of the spatial and temporal characteristics of a laser pulse is still a great challenge, especially when laser powers higher than hundreds of terawatts are involved. In this paper, by utilizing the radiative spin-flip effect, we find that the spin depolarization of an electron beam can be employed to diagnose characteristics of ultrafast ultraintense lasers with peak intensities around 1020–1022 W/cm2. With three shots, our machine-learning-assisted model can predict, simultaneously, the pulse duration, peak intensity, and focal radius of a focused Gaussian ultrafast ultraintense laser (in principle, the profile can be arbitrary) with relative errors of 0.1%–10%. The underlying physics and an alternative diagnosis method (without the assistance of machine learning) are revealed by the asymptotic approximation of the final spin degree of polarization. Our proposed scheme exhibits robustness and detection accuracy with respect to fluctuations in the electron beam parameters. Accurate measurements of ultrafast ultraintense laser parameters will lead to much higher precision in, for example, laser nuclear physics investigations and laboratory astrophysics studies. Robust machine learning techniques may also find applications in more general strong-field physics scenarios.

Abstract Introduction Hepatitis A virus infections are mostly asymptomatic or mildly symptomatic, and generally this disease has a benign course and resolves spontaneously. However, intrahepatic and rarer extrahepatic manifestations can complicate typical cases of acute hepatitis. Pleural effusion is an extremely rare extrahepatic entity with 20 cases reported in literature. Case presentation We report herein a recent case of both pleural effusion and ascites accompanying hepatitis A infection in a 5-year-old middle eastern child, diagnosed using serological testing and imaging studies, who was treated with supportive management with full resolution after 2 weeks. In addition, we review available literature regarding hepatitis A virus associated with pleural effusion using PubMed and summarize all reported cases in a comprehensive table. Results Literature contains 20 reported cases of serology-confirmed hepatitis A virus presenting with pleural effusion, most in the pediatric population with average age at presentation of 9 years 8 months. The majority of reported patients had right-sided pleural effusion (50%) or bilateral effusion (45%), while only 5% presented with pleural effusion on the left side. Hepatomegaly and ascites occurred concurrently in 80% and 70% respectively. Supportive treatment without invasive procedures (except one chylothorax case) yielded complete recovery in 95% of cases, while only one case progressed to fulminant liver failure followed by death. Conclusion Acute hepatitis A virus rarely presents with pleural effusion, usually following a benign course with spontaneous resolution in most patients. Pleural effusion does not change the prognosis or require any invasive treatment. Thus, further invasive procedures are not recommended and would only complicate this self-resolving benign condition.

An all-optical method of ultrafast spin rotation is put forward to precisely manipulate the polarization of relativistic charged particle beams of leptons or ions. Laser-driven dense ultrashort beams are manipulated via single-shot interaction with a copropagating temporally asymmetric laser pulse of moderate intensity. Using semiclassical numerical simulations, we show that the initial polarization of a lepton (proton) beam can be rotated to any desired orientation by a flexible control over the phase retardation between the spin precession and the momentum oscillation in a temporally asymmetrical (e.g., half-cycle terahertz or frequency-chirped) laser field. In particular, spin ultrafast rotation from the common transverse to the more valuable longitudinal polarization is feasible in a picosecond scale or less. Moreover, the beam quality, in terms of energy and angular divergence, is improved in the rotation process. This method has potential applications in various areas demanding ultrafast spin manipulation, like laser-plasma, laser-nuclear, and high-energy physics.

With the noticed steady increase of global demand for animal proteins coupled with the current farming practices falling short in fulfilling the requested quantities, more attention is being paid for means and methods intended to maximize every available agricultural-resource in a highly sustainable fashion to address the above growing gap between production and consumers' demand. Within this regard, considerable efforts are being invested either in identifying new animal feed ingredients or maximizing the utilization of already established ones. The public preference and awareness of the importance of using waste products generated by fruit-dependent industries (juice, jams, spirits, etc.) has improved substantially in recent years where a genuine interest of using the above waste(s) in meaningful applications is solidifying and optimization-efforts are being pursued diligently. While many of the earlier reported usages of fruit pomaces as feedstuffs suggested the possibility of using minimally processed raw materials alone, the availability of exogenous digestive and bio-conversion enzymes is promising to take such applications to new un-matched levels. This review will discuss some efforts and practices using exogenous enzymes to enhance fruit pomaces quality as feed components as well as their nutrients' accessibility for poultry and swine production purposes. The review will also highlight efforts deployed to adopt numerous naturally derived and environmentally friendly catalytic agents for sustainable future feed applications and animal farming-practices.

Recombinant proteins are becoming increasingly important for industrial applications, where Escherichia coli is the most widely used bacterial host for their production. However, the formation of inclusion bodies is a frequently encountered challenge for producing soluble and functional recombinant proteins. To overcome this hurdle, different strategies have been developed through adjusting growth conditions, engineering host strains of E. coli, altering expression vectors, and modifying the proteins of interest. These approaches will be comprehensively highlighted with some of the new developments in this review. Additionally, the unique features of protein inclusion bodies, the mechanism and influencing factors of their formation, and their potential advantages will also be discussed.

Cranberry processing by-products/pomace can be an excellent source of functionally bioactive molecules such as polyphenolics, complex carbohydrates, fibers, and nutritive minerals. While there are currently few applications for such processing-residues in poultry nutrition, there are many potential opportunities for the development of sustainable and value-added products. The aim of the current work was to investigate the effect(s) of four consecutive weeks of cranberry pomace (CBP) feeding on blood serum metabolic profiles and the cecal microbiota of pasture-raised broiler chickens. Six hundred day-old Cobb 500 broiler chicks were divided into three groups: one group receiving the basal diet, and two groups each receiving the basal diet supplemented with either 1 or 2% of CBP. Blood and cecal samples were collected from the birds before, during, and after the treatment over a period of 64 days for biochemical and 16S rRNA gene sequencing analysis, respectively. The detailed analysis of CBP (and formulated final feed) indicated its content in essential amino- and fatty acids in addition to its richness in dietary fibers. Incorporating the pomace in feed induced a dichotomous response in broilers, with short-term improvements in blood-serum iron and cholesterol levels coupled with long-term modulation of cecal microbiota characterized by an increase in beneficial bacterial taxa (including Bifidobacterium, unclassified_Rikenellaceae, and Faecalibacterium) while decreasing the presence of undesirable ones (unclassified_Synergistaceae and Desulfovibrio, and unclassified_Fusobacteriaceae). Overall, the outcome of this study suggests the possibility of using organic CBP as a feed supplement with potential ability to positively influence blood metabolites and gut microbial community composition in pasture-raised broiler chickens.

Abstract Considerable theoretical and experimental work has lately been focused on waves localized in time and space. In optics, waves of that nature are often referred to as light bullets. The most fascinating feature of light bullets is their propagation without appreciable distortion by diffraction or dispersion. Here, analytic expressions for the fields of an ultra-short, tightly-focused and arbitrary-order Bessel pulse are derived and discussed. Propagation in an under-dense plasma, responding linearly to the fields of the pulse, is assumed throughout. The derivation stems from wave equations satisfied by the vector and scalar potentials, themselves following from the appropriate Maxwell equations and linked by the Lorentz gauge. It is demonstrated that the fields represent well a pulse of axial extension, L, and waist radius at focus, w 0, both of the order of the central wavelength λ 0. As an example, to lowest approximation, the pulse of order l = 2 is shown to propagate undistorted for many centimeters, in vacuum as well as in the plasma. As such, the pulse behaves like a “light bullet” and is termed a “Bessel-Bessel bullet of arbitrary order”. The field expressions will help to better understand light bullets and open up avenues for their utility in potential applications.

Abstract The alarming number of recently reported human illnesses with bacterial infections resistant to multiple antibacterial agents has become a serious concern in recent years. This phenomenon is a core challenge for both the medical and animal health communities, since the use of antibiotics has formed the cornerstone of modern medicine for treating bacterial infections. The empirical benefits of using antibiotics to address animal health issues in animal agriculture (using therapeutic doses) and increasing the overall productivity of animals (using sub-therapeutic doses) are well established. The use of antibiotics to enhance profitability margins in the animal production industry is still practiced worldwide. Although many technical and economic reasons gave rise to these practices, the continued emergence of antimicrobial resistant bacteria is furthering the need to reduce the use of medically important antibiotics. This will require improving on-farm management and biosecurity practices, and the development of effective antibiotic alternatives that will reduce the dependence on antibiotics within the animal industry in the foreseeable future. A number of approaches are being closely scrutinized and optimized to achieve this goal, including the development of promising antibiotic alternatives to control bacterial virulence through quorum-sensing disruption, the use of synthetic polymers and nanoparticles, the exploitation of recombinant enzymes/proteins (such as glucose oxidases, alkaline phosphatases and proteases), and the use of phytochemicals. This review explores the most recent approaches within this context and provides a summary of practical mitigation strategies for the extensive use of antibiotics within the animal production chain in addition to several future challenges that need to be addressed.

Abstract The enzymatic detoxification of deoxynivalenol (DON) is a promising mitigation strategy for addressing this mycotoxin contamination of cereal grains. A recently described bacterium, Devosia mutans 17-2-E-8, capable of transforming DON into its non-toxic stereoisomer 3-epi-DON, holds promise for the development of such applications. Earlier observations suggested that DON epimerization proceeds via a two-step catalysis with 3-keto-DON as an intermediate. The results of this study indicate that NADPH is required for DON epimerization by cell-free protein extracts of D. mutans, while high concentrations of glucose and sucrose have a suppressive effect. Chemically synthesized 3-keto-DON incubated with D. mutans protein fractions enriched by ammonium sulfate precipitation at 35–55% saturation selectively reduced 3-keto-DON to 3-epi-DON, but fell short of supporting the complete epimerization of DON. In addition, seven Devosia species investigated for DON epimerization were all able to reduce 3-keto-DON to 3-epi-DON, but only a few were capable of epimerizing DON. The above observations collectively confirm that the enzymes responsible for the oxidation of DON to 3-keto-DON are physically separate from those involved in 3-keto-DON reduction to 3-epi-DON. The enzymatic nature of DON epimerization suggests that the process could be used to develop genetically engineered crops or microorganisms, ultimately reducing foodborne exposure of consumers and farm animals to DON.

Body reactions to drugs can manifest as Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). TEN is the most severe form of cutaneous reactions with an incidence rate of 1-2 per million cases per year. Despite TEN being a critical and life-threatening condition, there is little to no evidence of clear management protocol. We reported a 5-year-old male child who presented with lamotrigine-induced TEN and was successfully treated with intravenous immune globulin (IVIG) with a burn unit care level, while TEN treatment with IVIG is an appropriate approach with predictable good outcomes, burn unit care is also effective in creating highly favorable effects. Upon reviewing the literature, several studies indicate that TEN patients treated with the combination of IVIG and burn unit care lead to decreased levels of morbidity and mortality than when treated with IVIG or burn unit care alone. Therefore, treatment involving both IVIG and burn unit care should be considered for TEN patients.

Deoxynivalenol (DON) is a major fusarium toxin widely detected in cereal grains. The inadvertent exposure to this fungal secondary-metabolite gives rise to a myriad of adverse health effects including appetite loss, emesis, and suppression of the immune system. While most of the attention this mycotoxin has gained in the past four decades was related to its eukaryotic toxicity (monogastric animals and plants more precisely), recent studies have begun to reveal its negative influence on prokaryotes. Recently presented evidence indicates that DON can negatively affect many bacterial species, raising the possibility of DON-induced imbalances within the microbiota of the human and animal gut, in addition to other environmental niches. This in turn has led to a greater interest in understanding bacterial responses toward DON, and the involved mechanism(s) and metabolic pathways, in order to build a more comprehensive picture of DON-induced changes in both prokaryotes and eukaryotes alike. This study reveals the transcriptomic profiling of Devosia mutans strain 17-2-E-8 after the inclusion of DON within its growth medium. The results highlight three adaptive mechanisms involved in the response of D. mutans 17-2-E-8 to this mycotoxin, which include: (a) activation of adenosine 5’-triphosphate-binding cassette transporters; (b) engagement of a toxin-specific pyrroloquinoline quinone-dependent detoxification pathway; and finally (c) the upregulation of auxiliary coping proteins such as porins, glutathione S-transferases, and phosphotransferases. Some of the identified mechanisms are universal in nature and are shared with other bacterial genera and species.

A simple model is introduced for the fields of a chirped laser pulse. As an application, dynamics of laser-acceleration of a single electron by the fields of a pulse, with a sin4 envelope, is investigated. Multi-GeV energy gains from interaction with pulses of peak intensity I0~1020 W/cm2, are reported.

Automatic event recognition in sports photos is both an interesting and valuable research topic in the field of computer vision and deep learning. With the rapid increase and the explosive spread of data, which is being captured momentarily, the need for fast and precise access to the right information has become a challenging task with considerable importance for multiple practical applications, i.e., sports image and video search, sport data analysis, healthcare monitoring applications, monitoring and surveillance systems for indoor and outdoor activities, and video captioning. In this paper, we evaluate different deep learning models in recognizing and interpreting the sport events in the Olympic Games. To this end, we collect a dataset dubbed Olympic Games Event Image Dataset (OGED) including 10 different sport events scheduled for the Olympic Games Tokyo 2020. Then, the transfer learning is applied on three popular deep convolutional neural network architectures, namely, AlexNet, VGG-16 and ResNet-50 along with various data augmentation methods. Extensive experiments show that ResNet-50 with the proposed photobombing guided data augmentation achieves 90% in terms of accuracy.

Deoxynivalenol (DON) is one of the most common mycotoxins found in cereal grains and grains contaminated with DON can cause health issues for both humans and animals and result in severe economic losses. Currently there is no feasible method to remediate affected grains. The development of a biological method for detoxification is becoming increasingly more plausible with the discovery of microbes which can transform DON to a relatively non-toxic stereoisomer, 3-epi-DON. Although bacteria capable of detoxifying DON have been known for some time, it is only recently an enzyme responsible was identified. In Devosia mutans 17-2-E-8 (Devosia sp. 17-2-E-8) a two-step DON epimerization (Dep) pathway, designated as the Dep system, completes this reaction. DepA was recently identified as the enzyme responsible for the conversion of DON to 3-keto-DON, and in this report, DepB, a NADPH dependent dehydrogenase, is identified as the second and final step in the pathway. DepB readily catalyzes the reduction of 3-keto-DON to 3-epi-DON. DepB is shown to be moderately thermostable as it did not lose significant activity after a heat treatment at 55°C and it is amenable to lyophilization. DepB functions at a range of pH-values (5–9) and functions equally well in multiple common buffers. DepB is clearly a NADPH dependent enzyme as it utilizes it much more efficiently than NADH. The discovery of the final step in the Dep pathway may provide a means to finally mitigate the losses from DON contamination in cereal grains through an enzymatic detoxification system. The further development of this system will need to focus on the activity of the Dep enzymes under conditions mimicking industrially relevant conditions to test their functionality for use in areas such as corn milling, fuel ethanol fermentation or directly in animal feed.

Deoxynivalenol (DON) is a type B trichothecene mycotoxin that is commonly detected in cereals and grains world-wide. The low-tolerated levels of this mycotoxin, especially in mono-gastric animals, reflect its bio-potency. The toxicity of DON is conventionally attributed to its ability to inhibit ribosomal protein biosynthesis, but recent advances in molecular tools have elucidated novel mechanisms that further explain DON’s toxicological profile, complementing the diverse symptoms associated with its exposure. This article summarizes the recent findings related to novel mechanisms of DON toxicity as well as how structural modifications to DON alter its potency. In addition, it explores feasible ways of expanding our understating of DON-cellular targets and their roles in DON toxicity, clearance, and detoxification through the utilization of computational biology approaches.

Deoxynivalenol (DON) is a toxic secondary metabolite produced by several Fusarium species that infest wheat and corn. Food and feed contaminated with DON pose a health risk to both humans and livestock and form a major barrier for international trade. Microbial detoxification represents an alternative approach to the physical and chemical detoxification methods of DON-contaminated grains. The present study details the characterization of a novel bacterium, Devosia mutans 17-2-E-8, that is capable of transforming DON to a non-toxic stereoisomer, 3-epi-deoxynivalenol under aerobic conditions, mild temperature (25-30 oC), and neutral pH. The biotransformation takes place in the presence of rich sources of organic nitrogen and carbon without the need of DON to be the sole carbon source. The process is enzymatic in nature and endures a high detoxification capacity (3 µg DON/h/108 cells). The above conditions collectively suggest the possibility of utilizing the isolated bacterium as a feed treatment to address DON contamination under empirical field conditions.

Background and aim. Metabolic syndrome is recognised as a potential risk factor for the development of hepatocellular carcinoma (HCC). The association between metabolic factors and hepatitis C (HCV)-related HCC has not yet been well clarified. This study was conducted to elucidate the role of metabolic factors in HCV-related HCC.Material and methods. We recruited 147 HCC patients and compared them with 147 matched CHC patients and 320 controls. The plasma levels of homeostasis model assessment-IR (HOMA-IR), adiponectin and lipids for all participants were assessed.Results. The HCC group showed significantly hig-her levels of insulin, glucose, HOMA-IR and adiponectin as well as lower levels of total cholesterol, HDL-C, LDL-C, and triglycerides compared with the matched CHC patients and controls. HOMA-IR did not correlate with pathologic features of HCC, whereas serum adiponectin levels correlated positively with the size of tumour nodules (P = 0.009). Based on stepwise logistic regression analysis, age (OR: 1.456, 95% CI: 1.0721.979, P < 0.01), HOMA-IR (OR: 2.50, 95% CI: 1.70-3.69, P = 0.001), and adiponectin (OR: 1.585, 95% CI: 1.2691.980, P = 0.001) were independently associated with HCC.Conclusions. Metabolic abnormalities are closely associated with the occurrence and development of HCV-related HCC. Patients with CHC and high serum adiponectin levels face a higher risk of developing liver cancer. Insulin resistance, as measured by HOMA-IR, is significantly associated with HCV-related HCC.

Background & aim. Metabolic abnormalities are common in chronic hepatitis C infection (CHC). However, the genotypic differences of these disarrangements in patients infected with CHC genotype 4 (HCV-4) and its association with liver histology and viral loads remain unknown.Material and methods. We consecutively enrolled 183 HCV-4 patients and 106 healthy matched controls; to compare metabolic profiles and assess pattern of association of HCV RNA levels as well as histological factors with the serum lipid profile.Results. HCV-4 infection is associated with higher homeostasis model assessment of insulin resistance (HOMA-IR) index, despite that, a favourable lipid pattern, consisting of an elevation in HDLC and a reduction in serum cholesterol (TC), LDL-C and triglyceride (TG) levels, in comparison with normal matched adults. Significant fibrosis was independently associated with HOMA-IR, portal/periportal inflammation grade, serum cholesterol and age. Univariate association was elucidated between lower LDL-C and TC and Metavir activity score and between higher TG and TC and steatosis. In multivariate analysis, severe hepatitis activity, milder hepatic fibrosis, and triglyceride levels are associated with higher HCV RNA levels.Conclusion. HCV-4 is associated with wide metabolic changes. A proportional relationship is found between serum lipid profiles and hepatitis C viral load and liver histology in patients with HCV-4.

Perforation of the duodenum, which is usually retroperitoneal, is a known complication of endoscopic retrograde cholangiopancreatography (ERCP). Association of the duodenal perforation with pneumothorax is rare and the development of tension pneumothorax is even rarer. We report a case of tension pneumothorax following an ERCP, which we successfully treated with chest tube insertion and laparotomy, and systematically review the other 10 cases reported in the literature. Four of these 10 cases had tension pneumothorax. All were to the right side of the chest. Patients were mainly female (7/10). The median (range) age was 70.5 (55-89) years. Four patients required surgery (40%) and one patient, who was not operated on, died (10%). Clinicians should be aware of this serious complication. Unexplained chest pain, dyspnoea, and oxygen desaturation with abdominal distension during ERCP must raise this possibility. Early clinical recognition and prompt management is essential to improve the outcome.

Mycotoxins are secondary fungal metabolites associated with adverse human health and animal productivity consequences.[...]

Context. Pseudohypoaldosteronism type 1 (PHA1) is a life-threatening disease that causes severe hyperkalemia and cardiac arrest if not treated appropriately or if diagnosis is missed. Objective. To report a case of a newborn with vomiting and lethargy, ultimately diagnosed with pseudohypoaldosteronism. Patient. This case presented to the ED at an age of 14 days in hypovolemic shock. There was a family history of sudden infant death, her sister who was diagnosed with CAH and passed away at 3 months of age despite regular hormone replacement. Our patient had cardiac arrest in ED, due to hyperkalemia; while receiving fluid boluses, cardiopulmonary resuscitation was initiated. After stabilization, diagnostic workup demonstrated persistently low sodium, acidosis, and high potassium, which required peritoneal dialysis. Based on these findings, the patient was diagnosed with CAH. It turned out later that the patient had PHA1. Two years later, the patient had a new sibling with the same disease diagnosed at birth and started immediately on treatment without any complication. Conclusions and Outcome. This case highlights the significant diagnostic and therapeutic challenges in treating children with PHA1. Adrenal crisis is not always CAH; delayed diagnosis can lead to complication and even death. The presence of high plasma renin activity, aldosterone, and cortisol, along with the presence of hyponatremia and hyperkalemia, established the diagnosis of PHA type 1 and ruled out CAH.

This work provides an optimized extraction approach intended to maximize the recovery of dihydromyricetin (DHM) from Chinese vine tea (Ampelopsis grossedentata) leaves. The presented work adopts a Box-Behnken design as a response surface methodology to understand the role and influence of specific extraction parameters including: time, temperature, and solvent composition/ethanol (%) on DHM final yields. Initially, single factor experiments were used to delineate the role of above factors (temperature, time, and solvent composition) before proceeding with three factors-three levels Box-Behnken design with 17 separate runs to assess the effect of multifactorial treatments on DHM recovery rates. The collected data shows that independent variables (solvent composition, time, and temperature) can significantly affect DHM recovery rates with maximum yields resulting from a combined 60 °C, 60% aqueous ethanol, and 180 min treatment. From the empirical point of view, the above optimized extraction protocol can substantially enhance processing and profitability margins with a minimum need of interventions or associated costs.

Mycotoxins, the secondary metabolites of mycotoxigenic fungi, have been found in almost all agricultural commodities worldwide, causing enormous economic losses in livestock production and severe human health problems. Compared to traditional physical adsorption and chemical reactions, interest in biological detoxification methods that are environmentally sound, safe and highly efficient has seen a significant increase in recent years. However, researchers in this field have been facing tremendous unexpected challenges and are eager to find solutions. This review summarizes and assesses the research strategies and methodologies in each phase of the development of microbiological solutions for mycotoxin mitigation. These include screening of functional microbial consortia from natural samples, isolation and identification of single colonies with biotransformation activity, investigation of the physiological characteristics of isolated strains, identification and assessment of the toxicities of biotransformation products, purification of functional enzymes and the application of mycotoxin decontamination to feed/food production. A full understanding and appropriate application of this tool box should be helpful towards the development of novel microbiological solutions on mycotoxin detoxification.

Deoxynivalenol (DON) is a secondary fungal metabolite and contaminant mycotoxin that is widely detected in wheat and corn products cultivated around the world. Bio-remediation methods have been extensively studied in the past two decades and promising ways to reduce DON-associated toxicities have been reported. Bacterial epimerization of DON at the C3 carbon was recently reported to induce a significant loss in the bio-toxicity of the resulting stereoisomer (3-epi-DON) in comparison to the parental compound, DON. In an earlier study, we confirmed the diminished bio-potency of 3-epi-DON using different mammalian cell lines and mouse models and mechanistically attributed it to the reduced binding of 3-epi-DON within the ribosomal peptidyl transferase center (PTC). In the current study and by inspecting the chromatographic behavior of 3-epi-DON and its molecular interactions with a well-characterized enzyme, Fusarium graminearum Tri101 acetyltransferase, we provide the evidence that the C3 carbon epimerization of DON influences its molecular interactions beyond the abrogated PTC binding.

Post-translational modifications of histones play important roles in regulating nucleosome structure and gene transcription. It has been shown that biotinylation of histone H4 at lysine-12 in histone H4 (K12Bio-H4) is associated with repression of a number of genes. We hypothesized that biotinylation modifies the physical structure of nucleosomes, and that biotin-induced conformational changes contribute to gene silencing associated with histone biotinylation.To test this hypothesis we used atomic force microscopy to directly analyze structures of nucleosomes formed with biotin-modified and non-modified H4. The analysis of the AFM images revealed a 13% increase in the length of DNA wrapped around the histone core in nucleosomes with biotinylated H4. This statistically significant (p

Autoresonance laser acceleration of electrons is theoretically investigated using circularly polarized focused Gaussian pulses. Many-particle simulations demonstrate feasibility of creating over 10-GeV electron bunches of ultrahigh quality (relative energy spread of order 10^{-4}), suitable for fundamental high-energy particle physics research. The laser peak intensities and axial magnetic field strengths required are up to about 10^{18} W/cm^{2} (peak power ∼10 PW) and 60 T, respectively. Gains exceeding 100 GeV are shown to be possible when weakly focused pulses from a 200-PW laser facility are used. In our parametric study of this acceleration scheme, substantial challenges still need to be dealt with, especially on the road to realizing experimentally the required high magnetic field strengths and laser powers.

Calculations show that 10 keV helium and carbon ions, injected midway between two identical 1 TW-power crossed laser beams of radial polarization, can be accelerated in vacuum to energies of utility in ion lithography. As examples, identical laser beams, crossed at 10° and focused to waist radii of 7.42 μm, accelerate He^{2+} and C^{6+} ions to average kinetic energies near 75 and 165 keV over distances averaging less than 7 and 6 mm, respectively. The spread in kinetic energy in both cases is less than 1% and the particle average angular deflection is less than 7 mrad. More energy-demanding industrial applications require higher-power laser beams for their direct ion laser acceleration.

By numerically solving the relativistic equations of motion of a single electron in laser fields modeled by those of a Gaussian beam, we demonstrate electron capture by, reflection from, and transmission through the beam. In modeling the fields, terms of order up to ϵ^{5}, where ϵ is the diffraction angle, are retained. All cases of capture are accompanied by energy gain that may reach a few GeV, from fields of present-day intensities. Reflection and transmission, on the other hand, result sometimes in no gain or even in a loss of energy. It is shown that a laboratory static magnetic field may be used to eject a captured electron, a process that sometimes results in even more energy gain. For example, a 2.5 T uniform magnetic field suffices to eject a 3.633 MeV electron injected at 6° to the axis of a linearly polarized beam of a 10 PW power output and aimed at a point near the focus. Such an electron gains 1128 MeV from the laser field alone. However, it emerges with a 1230 MeV net energy gain under the additional action of the small magnetic field.

We point out that, the way it is reported, the solution to the equation of motion of a relativistic electron in the field of two electromagnetic waves advanced recently by Amatuni and Pogorelsky [Phys. Rev. ST Accel. Beams 1, 034001 (1998)] does not handle the case of two copropagating waves differing in frequency. An equivalent form for that solution is rigorously developed.