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This article provided a detailed analysis and discussion on the key points that affect the calibration accuracy of binocular cameras. A planar calibration board based on solid dot marker guided matching was designed, and its superiority over traditional calibration boards through experiments were verified. At the same time, an improved camera calibration method based on two-step RANSAC algorithm was proposed, and the calibration flow of binocular camera was designed for the improved calibration method. This method solves the problem of difficult target size calibration in images and has broad application prospects in the fields of online measurement of image targets and small target image recognition.

Haleakalā National Park and montane areas on east Maui, Hawaiian Archipelago, support critical nesting habitat for endangered ‘ua‘u Hawaiian petrel Pterodroma sandwichensis. Habitat loss, non-native predators, and damage by feral ungulates are limiting factors for ground-nesting petrels at Haleakalā and throughout Hawai‘i. Because nesting habitats differ among the Hawaiian Islands, habitat distribution modeling for Hawaiian petrel has been island specific. Based on 2453 known nest site locations, we provide the first landscape-scale predictive model describing relative abundance and habitat available for nesting petrels throughout upper Haleakalā (1830 to 3055 m). We evaluated (principal components analyses and Pearson’s correlation) 13 spatial landscape and climate predictor variables associated with nest sites and the background landscape followed by random forest modeling to predict nest site density. Six variables (elevation, slope, topographic position index at 2 scales, heat load index, presence-absence ash/cinder, and presence-absence vegetation) indicated nest sites occurred non-randomly throughout the central part of the summit and crater; greatest concentrations were predicted along the crater rim and a ridgeline extending southwest from the summit. Moderately high predicted density occurred in the northeastern and northern crater. Lower elevations to the north, west, and south flanks of Haleakalā had relatively fewer predicted nest sites. Although we focused on higher elevations on Haleakalā, there is no reason to suspect that conservation efforts would not be successful at lower elevations, provided nesting petrels were protected from invasive predators, grazing ungulates, and significant land alteration.

The pathogenesis of posterior longitudinal ligament ossification (OPLL) remains inadequately understood. Mechanical stimulation is one of the important pathogenic factors in OPLL. As one of the mechanical stimulation transduction signals, the yes-associated protein (YAP) interacts with the Wnt/β-catenin signalling pathway, which plays an important role in osteogenic differentiation. This study aimed to demonstrate the role of YAP-Wnt/β-catenin axis in cell differentiation induced by mechanical stress. Primary cells extracted from posterior longitudinal ligament tissues from OPLL or non-OPLL patients were subjected to sinusoidal uniaxial cyclic stretch (5 %, 0.5 Hz, 3 d). The expression of runt-related transcription factor 2, collagen I, osterix, osteocalcin and alkaline phosphatase were compared between the static and the experimental groups. In addition, the cytoskeleton was detected using phalloidin staining while YAP phosphorylation states and nuclear location were identified using immunofluorescence. The results showed that mechanical stretching loading increased the expression of osteogenic genes and proteins in the OPLL group, while it had no significant effect on the control group. When OPLL cells were stretched, YAP exhibited an obvious nuclear translocation and the Wnt/β-catenin pathway was activated. Knocking down YAP or β-catenin could weaken the impact upon osteogenic differentiation induced by mechanical stimulation. YAP-mediated mechanical stimulation promoted osteogenic differentiation of OPLL cells through Wnt/β-catenin pathway and this progress was independent of the Hippo pathway.

Direct laser acceleration of electrons during a high-energy, picosecond laser interaction with an underdense plasma has been demonstrated to be substantially enhanced by controlling the laser focusing geometry. Experiments using the OMEGA EP facility measured electrons accelerated to maximum energies exceeding 120 times the ponderomotive energy under certain laser focusing, pulse energy, and plasma density conditions. Two-dimensional particle-in-cell simulations show that the laser focusing conditions alter the laser field evolution, channel fields generation, and electron oscillation, all of which contribute to the final electron energies. The optimal laser focusing condition occurs when the transverse oscillation amplitude of the accelerated electron in the channel fields matches the laser beam width, resulting in efficient energy gain. Through this observation, a simple model was developed to calculate the optimal laser focal spot size in more general conditions and is validated by experimental data.

ABSTRACT This study investigated the effects of dietary Ferula supplementation on productive performance, egg quality, follicular development, serum levels of reproductive hormones, and reproductive gene expression in aged laying hens. A total of 300 Dawu pink laying hens (65 weeks old) were assigned to four treatments with six replicates per treatment and 10 hens per replicate. The birds were individually housed in wire cages and fed a corn-soybean meal-based diet with added Ferula at doses of 0, 50, 100, and 200 mg/kg for 12 weeks. The results showed that the laying rate in the 100 mg/kg Ferula-supplemented group was higher than in birds of the control group during weeks 1 to 12 (p

Insulin plays important roles in metabolic homeostasis during environmental challenges. The insulin receptor is a key molecule to receive and transduce insulin signals. In the present study, a novel insulin receptor was identified from the Chinese mitten crab Eriocheir sinensis (designated as EsIR). The coding region of EsIR gene was 3573 bp in length and encoded 1190 amino acids with all the functional domains of mammal insulin receptors, including furin-like domain, receptor L domain, transmembrane domain, and tyrosine kinase domain. Phylogenetic analysis showed that the EsIR shared the closest evolutionary relationship with the insulin receptor from Macrobrachium rosenbergii. Cell transfection experiments confirmed that EsIR proteins were localized on the cytomembrane. The mRNA transcripts of EsIR were widely distributed in various tissues with higher abundance in hepatopancreas and eyestalk of E. sinensis. After Aeromonas hydrophila stimulation, the expression level of EsIR mRNA decreased from 3 h to 6 h, and then increased at 12 h. The conserved structure and subcellular localization of EsIR together with its sensitivity to A. hydrophila stimulation implied that EsIR was probably involved in immune response of E. sinensis. The present study provided clues for the further investigation about the evolution and function of the insulin signaling pathway in invertebrates.

For research the behavior and after effects which had been resulted from the coated reactive fragments impacting the steel targets, the 14.5mm ballistic rifle had been adopted to complete the experiments that the 6mm Q235A steel targets was impacted by the steel fragments and the reactive fragments, composed by metal/ polymer coated with steel, with the same mass and size. Afterwards, the v50 ballistic-limited velocity and the law of the damage effects on the after effect-targets had been discovered. The results indicate that the integral strength of the coated reactive fragments was lower than that of the inert steel fragments, which lead to the reductions of the penetration performance. The v50 ballistic-limited velocity, resulted of the coated reactive fragments impacting the 6mm Q235A steel targets, was 709m/s and it was 1.33 times than that of the steel fragments with the same mass and size. The reaming enhanced effects on the after effect-targets could be produced in the condition that the impact velocity of coated reactive fragments should be greater than 900m/s while the residual velocity should be greater than 181m/s, and that it had been strengthened along with the impact velocity increased. The probable reasons of the damage enhanced effects had been analyzed that the coupled damage effects had been resulted from two parts energy. The results will provide important references to the engineering application of reactive fragments for warheads.

ABSTRACT Photoperiod and nutrition are major factors that affect the reproductive efficiency particularly in female animals. In this study we examined the interaction of photoperiod and food restriction on growth, sexual maturation and receptor mRNA expressions of leptin, melatonin, and estrogen in abdominal fat and the ovary of pullets. There were no interaction effects between photoperiod and feeding level on body weight, abdominal fat weight, ovary weight at both 14 wk and 18 wk. Abdominal fat weight of feed restriction group was significantly lower compared with the control group at the age of 14 wk, 18 wk, and age of the first egg (AFE) (p

Experimental measurements using the OMEGA EP laser facility demonstrated direct laser acceleration (DLA) of electron beams to (505 ± 75) MeV with (140 ± 30) nC of charge from a low-density plasma target using a 400 J, picosecond duration pulse. Similar trends of electron energy with target density are also observed in self-consistent two-dimensional particle-in-cell simulations. The intensity of the laser pulse is sufficiently large that the electrons are rapidly expelled along the laser pulse propagation axis to form a channel. The dominant acceleration mechanism is confirmed to be DLA and the effect of quasi-static channel fields on energetic electron dynamics is examined. A strong channel magnetic field, self-generated by the accelerated electrons, is found to play a comparable role to the transverse electric channel field in defining the boundary of electron motion.

Oyster, is a popular shellfish consumed globally. As a bivalve filter-feeding invertebrate mollusk, oyster harbors many microorganisms, which could eventually cause potential health risks of human. Microorganisms were correlated to oyster mortality, shelf life, spoilage, and foodborne pathogenic bacteria. Meanwhile, they could be adjusted by the preservative technologies in order to prolong the shelf life. With the development of molecular biological techniques, such as 16S Polymerase Chain Reaction (PCR), Real-time PCR, Temperature Gradient Gel Electrophoresis (TGGE), Denaturing Gradient Gel Electrophoresis (DGGE), Restriction Fragment Length Polymorphism (RFLP), Fluorescent in situ Hybridization (FISH), etc., microbiological diversity and spoilage mechanism of oyster can be further investigated. The spoilage microbiota belongs to Vibrio, Pseudomonas, Aeromonas, Bacillus, Enterobacteriaceae, Lactic Acid Bacteria (LAB), and Micrococcus, etc., and the main pathogens are Vibrio, Salmonella, Escherichia coli, Listeria, Staphylococcus, Photobacterium, and Shewanella according to current studies. However, little information is available for the spoilage mechanism of entire oyster and different tissues under different preservation conditions. This article reviews the oyster microbiota analysis methods, the impacts of aquaculture and pathogenic bacteria on oyster mortality and food safety, as well as initial and spoilage microbiotas in whole oyster and separated tissues during preservation.

Electron transport chain and oxidative phosphorylation are always a challenging topic for students studying metabolism. We had adopted blended learning in metabolism teaching and evaluated the learning experiences of students. In this project, a pre-class learning aid the "Story Mode" and a post-class learning aid the "Revision Mode" in the "Powerland" was developed that facilitated students learning electron transport chain and oxidative phosphorylation. In the "Story Mode," pathways were presented by short animations and simplified diagram that allowed students to understand basic concepts and recall simple facts of the topic. Students were asked to watch the animations before class to acquire lower level of cognitive learning first, and this facilitated students in understanding more complicated concepts later on during class. Another challenge that students faced was that they were especially weak at integrating metabolic pathways and understand the relationships between these pathways. A metro map was designed in the "Revision Mode" that aided students in knowledge integration, and the functions of biomolecules were summarized in flashcards that helped students in revising the concepts. This interactive self-learning tool was packaged as a courseware using the Articulate Storyline.

As data and protocols are increasingly generated, accessed, and manipulated electronically, many labs are shifting to storing data in electronic laboratory notebooks (ELNs). ELNs provide clear advantages in readability, shareability, searchability, accessibility, and data security over their paper counterparts. Our interdisciplinary program implemented ELNs across several sections of our gateway molecular biology laboratory course and analyzed the impact on 384 students (13 sections total from Fall 2016 to Spring 2018) using surveys, focus groups, and grade data. We found that students prefer the electronic format, citing the ease of transitioning to lab reports and the longevity of their data. Course grades overall were not affected by the change. Based on our experience, we offer suggestions for smoothing the transition to an ELN system in undergraduate and graduate laboratory courses, including use during remote teaching.

Focusing effect of laser-driven positron jets by self-generated target sheath fields has been observed for the first time experimentally and the results are supported by the computational studies. In the experiment, OMEGA EP short-pulse (0.7 ps, 500 J) irradiates mm-size gold targets with a concave back surface and reference flat-surface targets. Both targets exhibited positrons with quasi-monoenergetic energy peaks while targets with concave curvature also showed increased number of positrons at the detector. The data is consistent with hybrid-PIC simulations confirming that the time-varying electric fields driven by electrons escaping from the target significantly change the trajectories of positrons. These simulations show a small radius of curvature on the rear side increases the relative focusing effect and the positrons to electrons ratio in the escaping plasma. For the smallest radius of curvature, positron jets that are up to 10 times denser can be achieved.

The children aged under 5 years from vast African areas badly suffer from falciparum malaria and many of them die of this disease. Therapeutic efficacy of anti-malaria drugs, especially pyrimethamine-sulfadoxine (PS) and chloroquine (CQ) to falciparum malaria is frequently evaluated and reported in recent 10 years. Unfortunately, to date, these widespread materials and researches have not been systematically collected and analyzed. In our study, two investigators were employed to widely and independently gather researches on efficacy of PS vs. CQ mono-therapy of falciparum malaria in children aged below 5 years in unpublished and published databases. Meta-analyses were conducted in categories of PS group and CQ group respectively. Pooled OR of PS vs. CQ was 0.11 (95%CI, 0.05-0.24). PS showed higher therapeutic efficacy to falciparum malaria in less-than-5-year children than CQ. Random model was chosen to analyze for the heterogeneity existence between different studies. Subgroup analyses were performed, but heterogeneity was still presented. Heterogeneity might be caused by different resistance of falciparum malaria to PS and CQ in different settings. Malaria type associated with parasite species, basic information of PS and CQ, and PS & CQ resistant malaria control measures were demonstrated and discussed respectively in detail in this article.

Systematic cold biases exist in the simulation for 2 m air temperature in the Tibetan Plateau (TP) when using regional climate models and global atmospheric general circulation models. We updated the albedo in the Weather Research and Forecasting (WRF) Model lower boundary condition using the Global LAnd Surface Satellite Moderate-Resolution Imaging Spectroradiometer albedo products and demonstrated evident improvement for cold temperature biases in the TP. It is the large overestimation of albedo in winter and spring in the WRF model that resulted in the large cold temperature biases. The overestimated albedo was caused by the simulated precipitation biases and over-parameterization of snow albedo. Furthermore, light-absorbing aerosols can result in a large reduction of albedo in snow and ice cover. The results suggest the necessity of developing snow albedo parameterization using observations in the TP, where snow cover and melting are very different from other low-elevation regions, and the influence of aerosols should be considered as well. In addition to defining snow albedo, our results show an urgent call for improving precipitation simulation in the TP.

Superponderomotive-energy electrons are observed experimentally from the interaction of an intense laser pulse with a relativistically transparent target. For a relativistically transparent target, kinetic modeling shows that the generation of energetic electrons is dominated by energy transfer within the main, classically overdense, plasma volume. The laser pulse produces a narrowing, funnel-like channel inside the plasma volume that generates a field structure responsible for the electron heating. The field structure combines a slowly evolving azimuthal magnetic field, generated by a strong laser-driven longitudinal electron current, and, unexpectedly, a strong propagating longitudinal electric field, generated by reflections off the walls of the funnel-like channel. The magnetic field assists electron heating by the transverse electric field of the laser pulse through deflections, whereas the longitudinal electric field directly accelerates the electrons in the forward direction. The longitudinal electric field produced by reflections is 30 times stronger than that in the incoming laser beam and the resulting direct laser acceleration contributes roughly one third of the energy transferred by the transverse electric field of the laser pulse to electrons of the super-ponderomotive tail.

A series of experiments studying pre-plasma’s effect on electron generation and transport due to a high intensity laser were conducted on the OMEGA-EP laser facility. A controlled pre-plasma was produced in front of an aluminum foil target prior to the arrival of the high intensity short pulse beam. Energetic electron spectra were characterized with magnetic and bremsstrahlung spectrometers. Pre-plasma and pulse length were shown to have a large impact on the temperature of lower energy, ponderomotive scaling electrons. Super-ponderomotive electrons, seen in prior pre-plasma experiments with shorter pulses, were observed without any initial pre-plasma in our experiment. 2D particle-in-cell and radiation-hydrodynamic simulations shed light on and validate these experimental results.

The children aged under 5 years from vast African areas badly suffer from falciparum malaria and many of them die of this disease. Therapeutic efficacy of anti-malaria drugs, especially pyrimethamine-sulfadoxine (PS) and chloroquine (CQ) to falciparum malaria is frequently evaluated and reported in recent 10 years. Unfortunately, to date, these widespread materials and researches have not been systematically collected and analyzed. In our study, two investigators were employed to widely and independently gather researches on efficacy of PS vs. CQ mono-therapy of falciparum malaria in children aged below 5 years in unpublished and published databases. Meta-analyses were conducted in categories of PS group and CQ group respectively. Pooled OR of PS vs. CQ was 0.11 (95%CI, 0.05-0.24). PS showed higher therapeutic efficacy to falciparum malaria in less-than-5-year children than CQ. Random model was chosen to analyze for the heterogeneity existence between different studies. Subgroup analyses were performed, but heterogeneity was still presented. Hetero-geneity might be caused by different resistance of falciparum malaria to PS and CQ in different set-tings. Malaria type associated with parasite species, basic information of PS and CQ, and PS & CQ resistant malaria control measures were demonstrated and discussed respectively in detail in this arti-cle.

Acylcoenzyme A:cholesterol acyltransferase (ACAT) and/or cholesteryl esters have been implicated as important factors in the normal assembly of apolipoprotein (apoB)-containing lipoproteins. The predominant substrate for ACAT is believed to originate from cholesterol contained within the plasma membrane. To investigate a possible role of intestinal plasma membrane cholesterol in triacylglycerol-rich lipoprotein synthesis and secretion, CaCo-2 cells were incubated with agents that are known to interfere with cholesterol transport from the plasma membrane to the ER. Progesterone, verapamil, and trifluoperazine significantly decreased the movement of cholesterol from plasma membrane to endoplasmic reticulum (ER) in CaCo-2 cells. Without altering the synthesis of apoB and independent of their effects on cellular cholesterol esterification, progesterone, verapamil, and trifluoperazine decreased the basolateral secretion of triacylglycerols, cholesteryl esters, and immunoreactive and newly synthesized apoB. The three agents also interfered with the esterification of cholesterol absorbed from taurocholate micelles. As progesterone, verapamil, and trifluoperazine are recognized inhibitors of p-glycoprotein, a variety of agents that have been shown to interfere with p-glycoprotein function were tested to investigate their effects on cholesterol transport and apoB secretion. All the agents significantly decreased in parallel both cholesterol transport and apoB secretion. In contrast, methotrexate, an antimetabolite that does not interact with p-glycoprotein, had no effect. Nigericin, a potassium ionophore, which causes alkalinization of intracellular vesicles, also caused a profound inhibition of cholesterol transport and apoB secretion. Preventing plasma membrane cholesterol from arriving at the ER, or inhibiting the esterification of plasma membrane cholesterol, does not alter apoB secretion. However, the results suggest a possible role for p-glycoprotein in normal cholesterol trafficking and triacylglycerol-rich lipoprotein secretion in CaCo-2 cells. It is postulated that p-glycoprotein might function to maintain the acidic environment of transport vesicles, and therefore, could play a role in the transport of lipids by the intestine.

Elucidation of the secondary structure of the exchangeable apolipoproteins has been hindered by the difficulty in producing crystals suitable for X-ray spectrographic analyses. Consequently, in order to analyze potential structure-function relationships in the family of insect exchangeable apolipoproteins, apolipophorins-III (apoLps-III), two apoLps-III cDNA clones, one from the palo verde beetle (Derobrachus geminatus) and one from the house cricket (Acheta domesticus), have been isolated and sequenced. Multiple sequence alignments of the deduced protein sequences with two previously reported apolipophorins-III from Manduca sexta and Locusta migratoria reveal low sequence identity, suggesting that these proteins are very old and are highly divergent. Computer-assisted predictions of protein structure and subsequent analyses, using the known secondary structure of Locusta migratoria apolipophorin-III as a control, indicate that these insect proteins are composed of five amphipathic helices with characteristics similar to those of the helical domains of the mammalian exchangeable apolipoproteins. Thus, although insect and vertebrate exchangeable apolipoproteins share a common function in assisting lipid transport, precise amino acid identity is less important than the common structural feature of multiple amphipathic helices. Moreover, because these proteins occur widely among insect species, even in those where flight is limited or absent, we hypothesize that apolipophorin-III has a more generalized function in lipid metabolism than had been previously proposed.

The regulation of apoB synthesis and secretion by lipids present within bile was investigated in CaCo-2 cells grown on semipermeable filters. Bile acids decreased the basolateral secretion of immunoreactive apoB. Taurocholic acid decreased the secretion of newly synthesized apoB by increasing the rate of apoB degradation, but had no effect on the synthesis and secretion of apoA-I or trichloroacetic acid-precipitable proteins. The calcium ionophore, A23187, decreased apoB secretion similar to that observed for taurocholate. The addition of the ionophore and taurocholate together did not cause a further decrease in apoB secretion. Cholesterol or its hydroxylated derivative, 25-hydroxycholesterol, did not alter secretion of immunoreactive or newly synthesized apoB. Phosphatidylcholine increased apoB synthesis and secretion without affecting the synthesis or secretion of apoA-I. Phosphatidylcholine also reversed the effect of A23187 on apoB secretion. When phosphatidylcholine was added to the basolateral medium, apoB secretion was not altered. ApoB secretion was not increased by phospholipids of other classes. Dioleoylphosphatidylcholine increased apoB secretion, whereas dipalmitoylphosphatidylcholine did not. Fatty acid-labeled phosphatidylcholine was not hydrolyzed in the apical medium. Only 2% of the added phosphatidylcholine was cell-associated, and of this, 80% of the label remained as phosphatidylcholine with most of the remainder in triacylglycerols, fatty acids, and phosphatidylethanolamine. The results suggest that bile acids decrease apoB secretion by increasing its rate of degradation. This effect may be related to their ionophoric property. Cholesterol flux does not regulate apoB secretion. Phosphatidylcholine, independent of triacylglycerol flux and independent of its hydrolysis, increases the secretion of apoB by increasing apoB synthesis. Luminal phosphatidylcholine may play a role in apoB secretion in the intestine.

We developed a remote lab experience where freshmen grew and analyzed the activity of sourdough starters as a means of engaging with chemical engineering concepts. This six-week hands-on activity was targeted due to its low-cost, non-hazardous materials, and ability to be conducted safely in a non-laboratory setting. By designing the lab to be guided inquiry, we embraced the inherent variability students would encounter running these experiments remotely to create a motivating learning experience.

As more chemical engineering students enter careers beyond the field, students need more guidance in applying their problem solving skills to a challenges beyond the plant or refinery. Since Fall 2019, we have implemented case-based learning across our Material and Energy Balances course to help students practice chemical engineering thinking as a transferable and useful skill beyond typical process calculation examples. We share our approach and examples so other instructors may try teaching with cases.

Vertebrate retinas contain a high level of docosahexaenoic acid (DHA, 22:6n-3) and a relatively low level of arachidonic acid (AA, 20:4n-6). Although it is not known how DHA is selectively concentrated in the retina, the retinal pigment epithelium (RPE) is intimately involved in this process as these cells phagocytize shed rod outer segments (containing DHA) and take up DHA from the circulation. To explore the role of the RPE in the DHA enrichment in the retina, native frog RPE cells (RPE-eyecups) were incubated with [3H]DHA or [3H]AA for short times, or pulsed for up to 1 h with the two labeled fatty acids plus labeled glycerol simultaneously, followed by a chase for up to 7 h. The incorporation of label into various lipids was monitored by thin-layer or high performance liquid chromatography. In short-time incubations, a greater amount of DHA was incorporated into neutral lipids (primarily triglycerides, TG) compared with AA, while similar amounts of both fatty acids were found in phospholipids. On a relative basis, DHA was esterified mainly into TG, with AA into phospholipids. The uptake of each fatty acid correlated linearly with concentration (30-120 nM) and the incorporation pattern was distinct. Interestingly, the uptake and incorporation of labeled DHA or AA were not affected by the presence of unlabeled AA or DHA, respectively. In a pulse-chase experiment, RPE cells were active in the de novo synthesis of glycerolipids, particularly TG, which achieved a specific activity as high as diglycerides and ten times higher than the major phospholipids. The incorporation of DHA into most glycerolipids occurred to a large extent during de novo glycerolipid synthesis, whereas AA was incorporated mainly by deacylation-reacylation reactions. Our results suggest different metabolic pathways for handling DHA and AA in frog RPE. The preferential incorporation of DHA into TG suggests that TG might play an important role in the selective enrichment of DHA in the retina and in the recycling of photoreceptor DHA between the RPE and the retina.

Cone-guided fast ignition laser fusion depends critically on details of the interaction of an intense laser pulse with the inside tip of a cone. Generation of relativistic electrons in the laser plasma interaction (LPI) with a gold cone and their subsequent transport into a copper wire have been studied using a kJ-class intense laser pulse, OMEGA EP (850 J, 10 ps). We observed that the laser-pulse-energy-normalized copper K α signal from the Cu wire attached to the Au cone is significantly reduced (by a factor of 5) as compared to that from identical targets using the Titan laser (150 J, 0.7 ps) with 60 × less energy in the prepulse. We conclude that the decreased coupling is due to increased prepulse energy rather than 10 ps pulse duration, for which this effect has not been previously explored. The collisional particle-in-cell code PICLS demonstrates that the preformed plasma has a significant impact on generation of electrons and their transport. In particular, a longer scale length preplasma significantly reduces the energy coupling from the intense laser to the wire due to the larger offset distance between the relativistic critical density surface and the cone tip as well as a wider divergence of source electrons. We also observed that laser-driven plasma ionization increase in the LPI region can potentially alter the electron density profile during the laser interaction, forcing the electron source to be moved farther away from the cone tip which contributes to the reduction of energy coupling.

Experiments were performed on the Omega EP laser facility to study laser pulse propagation, channeling phenomena and electron acceleration from high-intensity, high-power laser interactions with underdense plasma. A CH plasma plume was used as the underdense target and the interaction of the laser pulse channeling through the plasma was imaged using proton radiography. High-energy electron spectra were measured for different experimental laser parameters. Structures observed along the channel walls are interpreted as having developed from surface waves, which are likely to serve as an injection mechanism of electrons into the cavitated channel for acceleration via direct laser acceleration mechanisms. Two-dimensional particle-in-cell simulations give good agreement with these channeling and electron acceleration phenomena.