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The article offers information on Alberto Rodriguez, editor of "The Journal of South Texas" and a member of the History and Political Sciences Department at Texas A&M University-Kingsville. Topics covered include his book "Urban Borderlands: Situating Race, Class and Ethnicity in South Texas 1910-1960," his work on Mexican immigrant and Mexican American identity, and the effects of the Lower Rio Grande Valley's transformation from an agricultural community into commercial centers.

Background: Lignocellulosic resources are promising feedstocks for the manufacture of bio-based products and bioenergy. However, the inherent recalcitrance of biomass to conversion into simple sugars currently hinders the deployment of advanced bioproducts at large scale. Lignin is a primary contributor to biomass recalcitrance as it protects cell wall polysaccharides from degradation and can inhibit hydrolytic enzymes via non-productive adsorption. Several engineering strategies have been designed to reduce lignin or modify its monomeric composition. For example, expression of bacterial 3-dehydroshikimate dehydratase (QsuB) in poplar trees resulted in a reduction in lignin due to redirection of metabolic flux toward 3,4-dihydroxybenzoate at the expense of lignin. This reduction was accompanied with remarkable changes in the pools of aromatic compounds that accumulate in the biomass. Results: The impact of these modifications on downstream biomass deconstruction and conversion into advanced bioproducts was evaluated in the current study. Using ionic liquid pretreatment followed by enzymatic saccharification, biomass from engineered trees released more glucose and xylose compared to wild-type control trees under optimum conditions. Fermentation of the resulting hydrolysates using Rhodosporidium toruloides strains engineered to produce α-bisabolene, epi-isozizaene, and fatty alcohols showed no negative impact on cell growth and yielded higher titers of bioproducts (as much as + 58%) in the case of QsuB transgenics trees. Conclusion: Our data show that low-recalcitrant poplar biomass obtained with the QsuB technology has the potential to improve the production of advanced bioproducts. [ABSTRACT FROM AUTHOR]

Background: Lignocellulosic resources are promising feedstocks for the manufacture of bio-based products and bioenergy. However, the inherent recalcitrance of biomass to conversion into simple sugars currently hinders the deployment of advanced bioproducts at large scale. Lignin is a primary contributor to biomass recalcitrance as it protects cell wall polysaccharides from degradation and can inhibit hydrolytic enzymes via non-productive adsorption. Several engineering strategies have been designed to reduce lignin or modify its monomeric composition. For example, expression of bacterial 3-dehydroshikimate dehydratase (QsuB) in poplar trees resulted in a reduction in lignin due to redirection of metabolic flux toward 3,4-dihydroxybenzoate at the expense of lignin. This reduction was accompanied with remarkable changes in the pools of aromatic compounds that accumulate in the biomass. Results: The impact of these modifications on downstream biomass deconstruction and conversion into advanced bioproducts was evaluated in the current study. Using ionic liquid pretreatment followed by enzymatic saccharification, biomass from engineered trees released more glucose and xylose compared to wild-type control trees under optimum conditions. Fermentation of the resulting hydrolysates using Rhodosporidium toruloides strains engineered to produce α-bisabolene, epi-isozizaene, and fatty alcohols showed no negative impact on cell growth and yielded higher titers of bioproducts (as much as + 58%) in the case of QsuB transgenics trees. Conclusion: Our data show that low-recalcitrant poplar biomass obtained with the QsuB technology has the potential to improve the production of advanced bioproducts. [ABSTRACT FROM AUTHOR]

We describe how to engineer wave-function delocalization in disordered systems modeled by tight-binding Hamiltonians in d>1 dimensions. We show analytically that a simple product structure for the random on-site potential energies, together with suitably chosen hopping strengths, allows a resonant scattering process leading to ballistic transport along one direction, and a controlled coexistence of extended Bloch states and anisotropically localized states in the spectrum. We demonstrate that these features persist in the thermodynamic limit for a continuous range of the system parameters. Numerical results support these findings and highlight the robustness of the extended regime with respect to deviations from the exact resonance condition for finite systems. The localization and transport properties of the system can be engineered almost at will and independently in each direction. This study gives rise to the possibility of designing disordered potentials that work as switching devices and band-pass filters for quantum waves, such as matter waves in optical lattices. [ABSTRACT FROM AUTHOR]

Automated grasping has a long history of research that is increasing due to interest from industry. One grand challenge for robotics is Universal Picking: the ability to robustly grasp a broad variety of objects in diverse environments for applications from warehouses to assembly lines to homes. Although many researchers now openly share code and data, it is challenging to compare and/or reproduce experimental results to identify which aspects of which approaches work best due to variations in assumptions and experimental protocols, e.g., sensors, lighting, robot arms, grippers, and objects. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Circadian Variations of Infarct Size in Acute Myocardial Infarction" by A. Suaárez-Barrientos, P. Lopez-Romero, and D. Vivas in a previous issue of 2011 and a response by the authors about their article is also presented.

Summary Somatic mutation in neurons is linked to neurologic disease and implicated in cell-type diversification. However, the origin, extent, and patterns of genomic mutation in neurons remain unknown. We established a nuclear transfer method to clonally amplify the genomes of neurons from adult mice for whole-genome sequencing. Comprehensive mutation detection and independent validation revealed that individual neurons harbor ∼100 unique mutations from all classes but lack recurrent rearrangements. Most neurons contain at least one gene-disrupting mutation and rare (0–2) mobile element insertions. The frequency and gene bias of neuronal mutations differ from other lineages, potentially due to novel mechanisms governing postmitotic mutation. Fertile mice were cloned from several neurons, establishing the compatibility of mutated adult neuronal genomes with reprogramming to pluripotency and development. [ABSTRACT FROM AUTHOR]

Dynamical localization prevents driven atomic systems from fast fragmentation by hampering the excitation process. We present numerical simulations within a collinear model of microwave-driven helium Rydberg atoms and prove that dynamical localization survives the impact of electron-electron interaction, even for doubly excited states in the presence of fast autoionization. We conclude that the effect of electron-electron repulsion on localization can be described by an appropriate rescaling of the atomic level density and of the external field with the strength of the interaction. [ABSTRACT FROM AUTHOR]

Missing traces in ground penetrating radar (GPR) B-scans (radargrams) may appear because of limited scanning resolution, failures during the acquisition process or the lack of accessibility to some areas under test. Four statistical interpolation methods for recovering these missing traces are compared in this paper: Kriging, Wiener structures, Splines and the expectation assuming an independent component analyzers mixture model (E-ICAMM). Kriging is an adaptation to the spatial context of the linear least mean squared error estimator. Wiener structures improve the linear estimator by including a nonlinear scalar function. Splines are a commonly used method to interpolate GPR traces. This consists of piecewise-defined polynomial curves that are smooth at the connections (or knots) between pieces. E-ICAMM is a new method proposed in this paper. E-ICAMM consists of computing the optimum nonlinear estimator (the conditional mean) assuming a non-Gaussian mixture model for the joint probability density in the observation space. The proposed methods were tested on a set of simulated data and a set of real data, and four performance indicators were computed. Real data were obtained by GPR inspection of two replicas of historical walls. Results show the superiority of E-ICAMM in comparison with the other three methods in the application of reconstructing incomplete B-scans. [ABSTRACT FROM AUTHOR]

Numerous pharmaceutical drugs have been repurposed for use as treatments for COVID-19 disease. These drugs have not consistently demonstrated high efficacy in preventing or treating this serious condition and all have side effects to differing degrees. We encourage the continued consideration of the use of the antioxidant and anti-inflammatory agent, melatonin, as a countermeasure to a SARS-CoV-2 infection. More than 140 scientific publications have identified melatonin as a likely useful agent to treat this disease. Moreover, the publications cited provide the rationale for the use of melatonin as a prophylactic agent against this condition. Melatonin has pan-antiviral effects and it diminishes the severity of viral infections and reduces the death of animals infected with numerous different viruses, including three different coronaviruses. Network analyses, which compared drugs used to treat SARS-CoV-2 in humans, also predicted that melatonin would be the most effective agent for preventing/treating COVID-19. Finally, when seriously infected COVID-19 patients were treated with melatonin, either alone or in combination with other medications, these treatments reduced the severity of infection, lowered the death rate, and shortened the duration of hospitalization. Melatonin’s ability to arrest SARS-CoV-2 infections may reduce health care exhaustion by limiting the need for hospitalization. Importantly, melatonin has a high safety profile over a wide range of doses and lacks significant toxicity. Some molecular processes by which melatonin resists a SARS-CoV-2 infection are summarized. The authors believe that all available, potentially beneficial drugs, including melatonin, that lack toxicity should be used in pandemics such as that caused by SARS-CoV-2. [ABSTRACT FROM AUTHOR]

Navigating along a set of programmed points in a completely unknown environment is a challenging task which mostly depends on the way the robot perceives and symbolizes the environment and decisions it takes in order to avoid the obstacles while it intends to reach subsequent goals. Tenacity and Traversability (T2)1-based strategies have demonstrated to be highly effective for reactive navigation, extending the benefits of the artificial Potential Field method to complex situations, such as trapping zones or mazes. This paper presents a new approach for reactive mobile robot behavior control which rules the actions to be performed to avoid unexpected obstacles while the robot executes a mission between several defined sites. This new strategy combines the T2 principles to escape from trapping zones together with additional criteria based on the Nearness Diagram (ND)13 strategy to move in cluttered or densely occupied scenarios. Success in a complete set of experiments, using a mobile robot equipped with a single camera, shows extensive environmental conditions where the strategy can be applied. [ABSTRACT FROM AUTHOR]

Presentation skills, such as oral expression and public speaking, have normally been relegated to the background in engineering degree programs. In recent years, however, the labor market has specifically demanded these kinds of skills in engineers. Accordingly, new engineering degrees, adapted to the goals of the Bologna Declaration or ABET criteria, consider presentation skills as being fundamental transferable skills. In practice, however, many engineering degree programs do not specifically foster these skills even though they are included in the syllabus. This paper proposes a presentation-skills training that uses the Master's thesis as an opportunity for fostering presentation-related skills. This activity has students deliver a scheduled series of rehearsals, in front of their classmates and tutors, for their officially assessed presentation of their Master's thesis work. The paper also presents a Web tool specifically designed for uploading recordings of the rehearsal presentations for feedback online as a complementary method for fostering presentation-related skills. Finally, the results of carrying out the proposed resource over a 4-year period from 2009 to 2013 are discussed; they show that students following the proposed methodology had higher than average marks, all receiving an A+, and 82% of them receiving an A+ with distinction. [ABSTRACT FROM AUTHOR]

The efficiency of linear power amplifiers can be improved by modulating its supply voltage according to the peak value of the signal that is being amplified in a technique usually known as envelope tracking. High bandwidth dc/dc converters called envelope amplifiers (EAs) are used to carry out the supply modulation in an efficient manner. In the case of linear RF power amplifiers, the bandwidth requirements over the EA strongly depend on the signal being amplified: in modern telecommunication applications it can range from several hundred kilohhertzs to a few tens of megahertz. The path to achieve such bandwidths usually goes through increased switching frequencies and/or reduced ratio of switching frequency to converter bandwidth. However, these may lead to lower converter efficiency and increased distortion, making the design of EAs a challenging task. This paper addresses the analysis and design of the output filter for Buck converters operating as EA. The output filter must provide enough attenuation at the switching frequency and harmonics to guarantee a desired level of distortion while enabling tracking of wide-bandwidth envelope signals with high converter efficiency. This paper focuses on the use of high-order filters (up to sixth-order Bessel-Thomson, Butterworth, and Legendre-Papoulis filters) in a buck dc/dc converter working as an EA. The filters are analytically described and characterized, and a design procedure that takes into account the major design constraints is proposed, allowing the selection of the appropriate filter for a given application. The proposed analysis and design method are supported by simulation results, as well as by experiments obtained using a 1 MHz buck converter operating as an EA. [ABSTRACT FROM AUTHOR]

A central question for regenerative neuroscience is whether synthetic neural circuits, such as those built from two species, can function in an intact brain. Here, we apply blastocyst complementation to selectively build and test interspecies neural circuits. Despite approximately 10–20 million years of evolution, and prominent species differences in brain size, rat pluripotent stem cells injected into mouse blastocysts develop and persist throughout the mouse brain. Unexpectedly, the mouse niche reprograms the birth dates of rat neurons in the cortex and hippocampus, supporting rat-mouse synaptic activity. When mouse olfactory neurons are genetically silenced or killed, rat neurons restore information flow to odor processing circuits. Moreover, they rescue the primal behavior of food seeking, although less well than mouse neurons. By revealing that a mouse can sense the world using neurons from another species, we establish neural blastocyst complementation as a powerful tool to identify conserved mechanisms of brain development, plasticity, and repair. [Display omitted] • Rat stem cells develop in mouse blastocysts to broadly populate two-species brains • Rat neurons develop synchronously and synapse with cognate mouse neurons • Genetic models of circuit loss or silencing unveil rescue capacity of exogenous neurons • Rat sensory neurons restore the primal behavior of food seeking to anosmic mice Generating brains from two different species via blastocyst complementation enables synchronous development of appropriate interspecies circuits. When host sensory neurons are disabled, donor neurons restore a primal odor-driven food-seeking behavior, showing that one species can sense and respond to the world through the cognate neurons of another. [ABSTRACT FROM AUTHOR]

Cables are complex, high-dimensional, and dynamic objects. Standard approaches to manipulate them often rely on conservative strategies that involve long series of very slow and incremental deformations, or various mechanical fixtures such as clamps, pins, or rings. We are interested in manipulating freely moving cables, in real time, with a pair of robotic grippers, and with no added mechanical constraints. The main contribution of this paper is a perception and control framework that moves in that direction, and uses real-time tactile feedback to accomplish the task of following a dangling cable. The approach relies on a vision-based tactile sensor, GelSight, that estimates the pose of the cable in the grip, and the friction forces during cable sliding. We achieve the behavior by combining two tactile-based controllers: (1) cable grip controller, where a PD controller combined with a leaky integrator regulates the gripping force to maintain the frictional sliding forces close to a suitable value; and (2) cable pose controller, where an linear–quadratic regulator controller based on a learned linear model of the cable sliding dynamics keeps the cable centered and aligned on the fingertips to prevent the cable from falling from the grip. This behavior is possible with the use of reactive gripper fitted with GelSight-based high-resolution tactile sensors. The robot can follow 1 m of cable in random configurations within two to three hand regrasps, adapting to cables of different materials and thicknesses. We demonstrate a robot grasping a headphone cable, sliding the fingers to the jack connector, and inserting it. To the best of the authors' knowledge, this is the first implementation of real-time cable following without the aid of mechanical fixtures. Videos are available at http://gelsight.csail.mit.edu/cable/ [ABSTRACT FROM AUTHOR]

Background: The development of bioenergy crops with reduced recalcitrance to enzymatic degradation represents an important challenge to enable the sustainable production of advanced biofuels and bioproducts. Biomass recalcitrance is partly attributed to the complex structure of plant cell walls inside which cellulose microfibrils are protected by a network of hemicellulosic xylan chains that crosslink with each other or with lignin via ferulate (FA) bridges. Overexpression of the rice acyltransferase OsAT10 is an effective bioengineering strategy to lower the amount of FA involved in the formation of cell wall crosslinks and thereby reduce cell wall recalcitrance. The annual crop sorghum represents an attractive feedstock for bioenergy purposes considering its high biomass yields and low input requirements. Although we previously validated the OsAT10 engineering approach in the perennial bioenergy crop switchgrass, the effect of OsAT10 expression on biomass composition and digestibility in sorghum remains to be explored. Results: We obtained eight independent sorghum (Sorghum bicolor (L.) Moench) transgenic lines with a single copy of a construct designed for OsAT10 expression. Consistent with the proposed role of OsAT10 in acylating arabinosyl residues on xylan with p-coumarate (pCA), a higher amount of p-coumaroyl-arabinose was released from the cell walls of these lines upon hydrolysis with trifluoroacetic acid. However, no major changes were observed regarding the total amount of pCA or FA esters released from cell walls upon mild alkaline hydrolysis. Certain diferulate (diFA) isomers identified in alkaline hydrolysates were increased in some transgenic lines. The amount of the main cell wall monosaccharides glucose, xylose, and arabinose was unaffected. The transgenic lines showed reduced lignin content and their biomass released higher yields of sugars after ionic liquid pretreatment followed by enzymatic saccharification. Conclusions: Expression of OsAT10 in sorghum leads to an increase of xylan-bound pCA without reducing the overall content of cell wall FA esters. Nevertheless, the amount of total cell wall pCA remains unchanged indicating that most pCA is ester-linked to lignin. Unlike other engineered plants overexpressing OsAT10 or a phylogenetically related acyltransferase with similar putative function, the improvements of biomass saccharification efficiency in sorghum OsAT10 lines are likely the result of lignin reductions rather than reductions of cell wall-bound FA. These results also suggest a relationship between xylan-bound pCA and lignification in cell walls. [ABSTRACT FROM AUTHOR]

This paper presents a new control strategy for power factor correctors (PFCs) used to drive high-brightness light-emitting diodes (HB-LEDs). This control strategy is extremely simple and is based on the use of standard peak-current-mode integrated controllers (PCMICs), reducing its cost and complexity in comparison to traditional PFC controllers. In fact, this method is an alternative implementation of the one-cycle control to PFCs belonging to the flyback family of converters, without introducing high complexity for reducing the total harmonic distortion. In this case, the use of a simple exponential compensation ramp instead of a linear one is the proposed solution for drawing a sinusoidal input current. Moreover, the line current is cycle-by-cycle controlled, and therefore, the input-current feedback loop is extremely fast, which allows the use of this type of control with high-frequency lines. The proposed idea is to apply this simple control to a one-stage PFC in order to design a low-cost ac–dc HB-LED driver. However, the application of this control strategy to PFC belonging to the flyback family of converters is not obvious. Design-oriented considerations about its implementation in PCMIC will be provided. Finally, an experimental prototype of this driver was developed. [ABSTRACT FROM PUBLISHER]

Similar pathophysiological mechanisms within autoimmune diseases have stimulated searches for common genetic roots. Polyautoimmunity is defined as the presence of more than one autoimmune disease in a single patient. When three or more autoimmune diseases coexist, this condition is called multiple autoimmune syndrome (MAS). We analyzed the presence of polyautoimmunity in 1,083 patients belonging to four autoimmune disease cohorts. Polyautoimmunity was observed in 373 patients (34.4%). Autoimmune thyroid disease (AITD) and Sjögren's syndrome (SS) were the most frequent diseases encountered. Factors significantly associated with polyautoimmunity were female gender and familial autoimmunity. Through a systematic literature review, an updated search was done for all MAS cases (January 2006-September 2011). There were 142 articles retrieved corresponding to 226 cases. Next, we performed a clustering analysis in which AITD followed by systemic lupus erythematosus and SS were the most hierarchical diseases encountered. Our results indicate that coexistence of autoimmune diseases is not uncommon and follows a grouping pattern. Polyautoimmunity is the term proposed for this association of disorders, which encompasses the concept of a common origin for these diseases. [ABSTRACT FROM AUTHOR]

Similar pathophysiological mechanisms within autoimmune diseases have stimulated searches for common genetic roots. Polyautoimmunity is defined as the presence of more than one autoimmune disease in a single patient. When three or more autoimmune diseases coexist, this condition is called multiple autoimmune syndrome (MAS). We analyzed the presence of polyautoimmunity in 1,083 patients belonging to four autoimmune disease cohorts. Polyautoimmunity was observed in 373 patients (34.4%). Autoimmune thyroid disease (AITD) and Sjögren's syndrome (SS) were the most frequent diseases encountered. Factors significantly associated with polyautoimmunity were female gender and familial autoimmunity. Through a systematic literature review, an updated search was done for all MAS cases (January 2006-September 2011). There were 142 articles retrieved corresponding to 226 cases. Next, we performed a clustering analysis in which AITD followed by systemic lupus erythematosus and SS were the most hierarchical diseases encountered. Our results indicate that coexistence of autoimmune diseases is not uncommon and follows a grouping pattern. Polyautoimmunity is the term proposed for this association of disorders, which encompasses the concept of a common origin for these diseases. [ABSTRACT FROM AUTHOR]

Coronary artery disease (CAD) is a complex disease with genetic and environmental determinants. Although a large number of genetic polymorphisms involved in the pathogenesis of atherosclerosis have been identified, there is still no evidence of a genetic association with CAD. As melatonin might play a role in the pathogenesis of atherosclerosis through its anti-inflammatory and antioxidant properties, we tested whether the expression of six single nucleotide polymorphisms (SNPs) of the melatonin receptor differs in acute myocardial infarction (AMI) patients with acute myocardial infarction (n = 300) compared with healthy age- and sex-matched controls (n = 250). Finally, only MEL1A receptor SNP rs28383653 was selected because of Hardy-Weinberg equilibrium (χ2 = 0.49). The distribution of genotype frequencies for this SNP showed that the unfavourable CT genotype was significantly more frequent in patients with AMI than in controls (4.5% versus 1.3%; P = 0.006). Multivariable analysis showed a significantly higher frequency of the unfavourable CT genotype in AMI patients with peripheral arteriopathy (28% versus 10%; P = 0.01). This finding suggests a synergism effect between the unfavourable genotype (CT) of the MELIA receptor SNP and the vascular disease in this subgroup of patients. To our knowledge, this is the first study to report an association between a genetic polymorphism of the melatonin receptor 1A and CAD. [ABSTRACT FROM AUTHOR]

Objective  This study estimates the association of a first trimester finding of subchorionic hematoma (SCH) with third trimester adverse pregnancy outcomes in women with twin pregnancies. Study Design  Retrospective cohort study of twin pregnancies prior to 14 weeks at a single institution from 2005 to 2019, all of whom had a first trimester ultrasound. We excluded monoamniotic twins, fetal anomalies, history of fetal reduction or spontaneous reduction, and twin-to-twin transfusion syndrome. Ultrasound data were reviewed, and we compared pregnancy outcomes after 24 weeks in women with and without a SCH at their initial ultrasound 6 0/7 to 13 6/7 weeks. Regression analysis was used to control for any differences in baseline characteristics. Results  A total of 760 women with twin pregnancies met inclusion criteria for the study, 68 (8.9%) of whom had a SCH. Women with SCH were more likely to have vaginal bleeding and had their initial ultrasound at earlier gestational ages. On univariate analysis, SCH was not significantly associated with gestational age at delivery, preterm birth, birthweight of either twin, low birthweight percentiles of either twin, fetal demise, or preeclampsia. SCH was associated with placental abruption on univariate analysis, but not after controlling for vaginal bleeding and gestational age at the time of the initial ultrasound (adjusted odds ratio: 2.00, 95% confidence interval: 0.63–6.42). Among women with SCH, SCH size was not associated with adverse pregnancy outcomes. Conclusion  In women with twin pregnancies, the finding of a first trimester SCH is not associated with adverse pregnancy outcomes >24 weeks. [ABSTRACT FROM AUTHOR]

Background: The accuracy of current prediction tools for ischaemic and bleeding events after an acute coronary syndrome (ACS) remains insufficient for individualised patient management strategies. We developed a machine learning-based risk stratification model to predict all-cause death, recurrent acute myocardial infarction, and major bleeding after ACS.Methods: Different machine learning models for the prediction of 1-year post-discharge all-cause death, myocardial infarction, and major bleeding (defined as Bleeding Academic Research Consortium type 3 or 5) were trained on a cohort of 19 826 adult patients with ACS (split into a training cohort [80%] and internal validation cohort [20%]) from the BleeMACS and RENAMI registries, which included patients across several continents. 25 clinical features routinely assessed at discharge were used to inform the models. The best-performing model for each study outcome (the PRAISE score) was tested in an external validation cohort of 3444 patients with ACS pooled from a randomised controlled trial and three prospective registries. Model performance was assessed according to a range of learning metrics including area under the receiver operating characteristic curve (AUC).Findings: The PRAISE score showed an AUC of 0·82 (95% CI 0·78-0·85) in the internal validation cohort and 0·92 (0·90-0·93) in the external validation cohort for 1-year all-cause death; an AUC of 0·74 (0·70-0·78) in the internal validation cohort and 0·81 (0·76-0·85) in the external validation cohort for 1-year myocardial infarction; and an AUC of 0·70 (0·66-0·75) in the internal validation cohort and 0·86 (0·82-0·89) in the external validation cohort for 1-year major bleeding.Interpretation: A machine learning-based approach for the identification of predictors of events after an ACS is feasible and effective. The PRAISE score showed accurate discriminative capabilities for the prediction of all-cause death, myocardial infarction, and major bleeding, and might be useful to guide clinical decision making.Funding: None. [ABSTRACT FROM AUTHOR]

The last five years marked a surge in interest for and use of smart robots, which operate in dynamic and unstructured environments and might interact with humans. We posit that well-validated computer simulation can provide a virtual proving ground that in many cases is instrumental in understanding safely, faster, at lower costs, and more thoroughly how the robots of the future should be designed and controlled for safe operation and improved performance. Against this backdrop, we discuss how simulation can help in robotics, barriers that currently prevent its broad adoption, and potential steps that can eliminate some of these barriers. The points and recommendations made concern the following simulation-in-robotics aspects: simulation of the dynamics of the robot; simulation of the virtual world; simulation of the sensing of this virtual world; simulation of the interaction between the human and the robot; and, in less depth, simulation of the communication between robots. This Perspectives contribution summarizes the points of view that coalesced during a 2018 National Science Foundation/Department of Defense/National Institute for Standards and Technology workshop dedicated to the topic at hand. The meeting brought together participants from a range of organizations, disciplines, and application fields, with expertise at the intersection of robotics, machine learning, and physics-based simulation. [ABSTRACT FROM AUTHOR]

Animal models of human antigen-specific B cell receptors (BCRs) generally depend on "inferred germline" sequences, and thus their relationship to authentic naive human B cell BCR sequences and affinities is unclear. Here, BCR sequences from authentic naive human VRC01-class B cells from healthy human donors were selected for the generation of three BCR knockin mice. The BCRs span the physiological range of affinities found in humans, and use three different light chains (VK3-20, VK1-5, and VK1-33) found among subclasses of naive human VRC01-class B cells and HIV broadly neutralizing antibodies (bnAbs). The germline-targeting HIV immunogen eOD-GT8 60mer is currently in clinical trial as a candidate bnAb vaccine priming immunogen. To attempt to model human immune responses to the eOD-GT8 60mer, we tested each authentic naive human VRC01-class BCR mouse model under rare human physiological B cell precursor frequency conditions. B cells with high (HuGL18HL) or medium (HuGL17HL) affinity BCRs were primed, recruited to germinal centers, and they affinity matured, and formed memory B cells. Precursor frequency and affinity interdependently influenced responses. Taken together, these experiments utilizing authentic naive human VRC01-class BCRs validate a central tenet of germline-targeting vaccine design and extend the overall concept of the reverse vaccinology approach to vaccine development. [ABSTRACT FROM AUTHOR]

A letter to the editor in response to the article "Hypertrophic cardiomyopathy," by Barry Maron and Martin Maron in the January 19, 2013 issue is presented, with authors' reply.

• There is a great need for economically viable methods for upcycling of waste plastics. • One promising approach is depolymerization followed by biological conversion. • Upcycling polyolefins by this method requires cleaving carbon-carbon bonds. • Carbon-carbon bonds can be cleaved with aqueous Fenton chemistry in sulfonated polymers. • We combined experimental studies with ab initio quantum chemical calculations to study this process in detail for polystyrene sulfonate (PSS). Experimental studies and ab initio quantum chemistry calculations were combined to investigate the process by which a Fenton reaction breaks down polystyrene sulfonate. The experimental results show that both molecular weight reduction and loss of aromaticity occur nearly simultaneously, a finding that is supported by the calculations. The results show that more than half of the material is broken down to low molecular weight compounds (< 500 g/mol) with two molar equivalents of H 2 O 2 per styrene monomer. The calculations provide insights into the reaction pathways and indicate that at least two hydroxyl radicals are required to cleave backbone C C bonds or to eliminate aromaticity. The calculations also show that, of the aromatic carbons, hydroxyl radical is most likely to add to the carbon bonded to sulfur. This finding explains the loss of hydrogen sulfite anion early in the process and also the efficient reduction of Fe(III) to Fe(II) through semiquinone formation. Taken together the experimental and computational results indicate that the reaction is very efficient and that very little H 2 O 2 is lost to unproductive reactions. This high efficiency is attributed to the close association of Fe atoms with the sulfonate group such that hydroxyl radicals are generated near the polymer chains. [ABSTRACT FROM AUTHOR]

In this paper, the third quadrant behavior of a high-voltage superjunction mosfet (SJ-FET) in cascode configuration (CC) with a low-voltage silicon mosfet is deeply studied by means of an analytical model and experimental data. The third quadrant dynamic behavior of the SJ-CCs is compared to the standalone counterparts by evaluating their reverse recovery time (tRR), reverse recovery peak current (IRRM), and reverse recovery charge (QRR). An analytical model and experimental results show that the SJ-CC avoids or mitigates the activation of the SJ-FET body diode during the third quadrant operation. As a consequence, the SJ-CC strongly improves the widely used figure-of-merit RON·QRR, which considers the on-state resistance of the transistors (RON). In addition, the results obtained using an SJ-CC are similar or better than those achieved by SJ-FETs with enhanced reverse recovery (i.e., irradiated SJ-FETs). This paper also includes a comparison with commercial wide bandgap switches, concluding that the RON·QRR value provided by the SJ-CC is around eight times higher than that provided by a commercial GaN cascode. [ABSTRACT FROM AUTHOR]

Achieving low cost and high efficiency lignocellulose deconstruction is a critical step towards widespread adoption of lignocellulosic biofuels. Certain ionic liquid (IL)-based pretreatment processes effectively reduce recalcitrance of lignocellulose to enzymatic degradation but require either costly separations following pretreatment or novel IL compatible processes to mitigate downstream toxicity. Here we demonstrate at benchtop and pilot bioreactor scales a separation-free, intensified process for IL pretreatment, saccharification, and fermentation of sorghum biomass to produce the sesquiterpene bisabolene, a precursor to the renewable diesel and jet fuel bisabolane. The deconstruction process employs the IL cholinium lysinate ([Ch][Lys]), followed by enzymatic saccharification with the commercial enzyme cocktails Cellic CTec2 and HTec2. Glucose yields above 80% and xylose yields above 60% are observed at all scales tested. Unfiltered hydrolysate is fermented directly by Rhodosporidium toruloides– with glucose, xylose, acetate and lactate fully consumed during fermentation at all scales tested. Bisabolene titers improved with scale from 1.3 g L−1 in 30 mL shake flasks to 2.2 g L−1 in 20 L fermentation. The combined process enables conversion of saccharified IL-pretreated biomass directly to advanced biofuels with no separations or washing, minimal additions to facilitate fermentation, no loss of performance due to IL toxicity, and simplified fuel recovery via phase separation. This study is the first to demonstrate a separation-free IL based process for conversion of biomass to an advanced biofuel and is the first to demonstrate full consumption of glucose, xylose, acetate, and lactic acid in the presence of [Ch][Lys]. [ABSTRACT FROM AUTHOR]

This paper presents an overview of the inaugural Amazon Picking Challenge along with a summary of a survey conducted among the 26 participating teams. The challenge goal was to design an autonomous robot to pick items from a warehouse shelf. This task is currently performed by human workers, and there is hope that robots can someday help increase efficiency and throughput while lowering cost. We report on a 28-question survey posed to the teams to learn about each team’s background, mechanism design, perception apparatus, planning, and control approach. We identify trends in this data, correlate it with each team’s success in the competition, and discuss observations and lessons learned based on survey results and the authors’ personal experiences during the challenge.

Note to Practitioners—Perception, motion planning, grasping, and robotic system engineering have reached a level of maturity that makes it possible to explore automating simple warehouse tasks in semistructured environments that involve high-mix, low-volume picking applications. This survey summarizes lessons learned from the first Amazon Picking Challenge, highlighting mechanism design, perception, and motion planning algorithms, as well as software engineering practices that were most successful in solving a simplified order fulfillment task. While the choice of mechanism mostly affects execution speed, the competition demonstrated the systems challenges of robotics and illustrated the importance of combining reactive control with deliberative planning. [ABSTRACT FROM AUTHOR]

This paper addresses the identification of the inertial parameters and the contact forces associated with objects making and breaking frictional contact with the environment. Our goal is to explore under what conditions, and to what degree, the observation of physical interaction, in the form of motions and/or applied external forces, is indicative of the underlying dynamics that governs it. In this study we consider the cases of passive interaction, where an object free-falls under gravity, and active interaction, where known external perturbations act on an object at contact. We assume that both object and environment are planar and rigid, and exploit the well-known complementarity formulation for contact resolution to establish a constrained optimization-based problem to estimate inertial parameters and contact forces. We also show that when contact modes are known, or guessed, the formulation provides a closed-form relationship between inertial parameters, contact forces, and observed motions, that turns into a least squares problem.Consistent with intuition, the analysis indicates that without the application of known external forces, the identifiable set of parameters remains coupled, i.e. the ratio of mass moment of inertia to mass and the ratio of contact forces to the mass. Interestingly the analysis also shows that known external forces can lead to decoupling and identifiability of mass, mass moment of inertia, and normal and tangential contact forces. We evaluate the proposed algorithms both in simulation and with real experiments for the cases of a free falling square, ellipse, and rimless wheel interacting with the ground, as well as a disk interacting with a manipulator. [ABSTRACT FROM AUTHOR]