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Introducción. La resistencia a los carbapenémicos se define como la producción de enzimas capaces de inactivar la acción de los antibióticos. Sin embargo, debido al incremento alarmante de la resistencia, se los utiliza con mayor frecuencia, llevando al aumento de la resistencia. Los carbapenémicos son β-lactámicos de amplio espectro con actividad bactericida frente a bacterias Gram positivas y Gramnegativas, considerados como antibióticos de reserva. Objetivo. El objetivo de la presente investigación fue describir la frecuencia de enterobacterias resistentes a carbapenémicos a partir de aislados clínicos, del Hospital Vicente Corral Moscoso durante el periodo 2019-2020. Método. El estudio fuede tipo descriptivo, documental secundario. Resultados. La investigación recopiló un universo de 3732 cultivos positivos, los que presentaron resistencia a los carbapenémicos fueron 400 que corresponde al 10,7% de aislados. El género masculino fue el más representativo con el 60,2% frente al 39,75% del género femenino. El análisis de frecuencia evidenció que, el área de emergencia fue la más representativa con el 59,8% seguido de hospitalización con el 31,3% y UCI con el 7,9%. En el análisis por tipo de muestra se observó resistencia en secreciones respiratorias con un 54,2%. En cuanto a las especies bacterianas se evidenció el predominio de Klebsiella pneumoniae con el 86%, frente al 14% de otras especies. Conclusiones: El presente trabajo sugiere la existencia de un aumento considerable de casos de resistencia a los carbapenémicos en comparación con los diferentes tipos de muestras estudiadas, con predominio de secreciones respiratorias, con el dominio de Klebsiella pneumonie frente a las demás especies bacterianas.

Amyotrophic lateral sclerosis (ALS) is a disease that progressively annihilates spinal cord motor neurons, causing severe motor decline and death. The disease is divided into familial and sporadic ALS. Mutations in the TAR DNA binding protein 43 (TDP-43) have been involved in the pathological emergence and progression of ALS, although the molecular mechanisms eliciting the disease are unknown. Transposable elements (TEs) and DNA sequences capable of transposing within the genome become dysregulated and transcribed in the presence of TDP-43 mutations. We performed RNA-Seq in human motor neurons (iMNs) derived from induced pluripotent stem cells (iPSCs) from TDP-43 wild-type—iMNs-TDP-43WT—and mutant—iMNs-TDP-43M337V—genotypes at 7 and 14 DIV, and, with state-of-the-art bioinformatic tools, analyzed whether TDP-43M337V alters both gene expression and TE activity. Our results show that TDP-43M337V induced global changes in the gene expression and TEs levels at all in vitro stages studied. Interestingly, many genetic pathways overlapped with that of the TEs activity, suggesting that TEs control the expression of several genes. TEs correlated with genes that played key roles in the extracellular matrix and RNA processing: all the regulatory pathways affected in ALS. Thus, the loss of TE regulation is present in TDP-43 mutations and is a critical determinant of the disease in human motor neurons. Overall, our results support the evidence that indicates TEs are critical regulatory sequences contributing to ALS neurodegeneration.

Background The World Health Organization (WHO) has established the AWaRe (Access, Watch and Reserve) classification based on the impact of different antibiotics on antimicrobial resistance. For ambulatory patients, WHO recommends Access antibiotics to represent >60% of all prescriptions, and an Access to Watch (AW) index of ≥1.5. The use of Access and Watch antibiotics has not been evaluated in ambulatory patients in Latin America. The aim of this study was to describe antibiotic use among members of two health plans within a private health insurance in Bolivia. Methods We retrospectively evaluated antibiotic use among 8,405 members of a private healthcare system in Santa Cruz de la Sierra, Bolivia, between Jan-2017 and Dec-2018. Antibiotic use was calculated as defined daily doses (DDD) per 1,000 member-days, and compared between two plans, one a Health Maintenance Organization (HMO) (2,419 members) and the other a Preferred Provider Organization (PPO) (5,986 members). In the HMO plan, members have a general practitioner (GP) as the primary point of care, whereas in the PPO plan, members can access specialists directly without a referral from the GP. Differences between groups were calculated using Byar test with 95% confidence intervals (CI). Results Antibiotic use in DDD/1,000 member-days for the study period was 8.31 in ambulatory, 10.7 in the Emergency Department, and 0.72 in the hospital. Ambulatory antibiotic use in the HMO plan was lower than the PPO plan (6.95 vs. 8.89 DDD/1,000 member-days; diff. –1.94, 95%CI –2.15 to –1.72) (Table). Of all ambulatory antibiotics, 55% were Access and 45% were Watch (AW index: 1.24). By patient group, 52% of pediatric and 58% of adult prescriptions were Access; diff. –6%; p< 0.001 (AW index: 1.07 and 1.39, respectively). By health plan, 62% of HMO and 53% of PPO antibiotics were Access; diff. 9%; p< 0.001 (AW index: 1.13 and 1.67, respectively). Conclusion Ambulatory antibiotic use in this cohort was high. Overall use of Access antibiotics was lower than the recommended by WHO; however, we found less broad-spectrum antibiotic use in the HMO plan compared to the PPO plan. These findings highlight the urgent need for antibiotic stewardship in the ambulatory setting, and the important role of GPs in appropriate antibiotic prescribing. Disclosures Sara E. Cosgrove, MD, Basilea: Member of Infection Adjudication Committee.

Background Several countries in Latin America reported an increase in antibiotic use during the first wave of the COVID-19 Pandemic. Methods We retrospectively evaluated antibiotic use among 10,752 members of a private healthcare system in Santa Cruz de la Sierra, Bolivia, between Jan-Dec 2019 (pre-pandemic) and Jan-Aug 2020 (pandemic). Antibiotic use was calculated as daily defined doses (DDD) per 1,000 member-days, per 100 ambulatory visits, and per 100 inpatient-days, and categorized using the World Health Organization classification (Access, Watch, and Reserve), based on the impact of different antibiotics on antimicrobial resistance. In April 2020, the antibiotic stewardship team developed COVID-19 treatment guidelines for ambulatory and hospitalized patients and provided recommendations on all patients hospitalized due to COVID-19. Due to the nature of the network, guideline use is usually high. During the pandemic period and due to local restrictions, patient interactions were mostly limited to COVID-19 presentations. Differences with 95% confidence intervals (CI) between groups were estimated. Results Pandemic and pre-pandemic antibiotic use in DDD/1,000 member-days was 8.48 and 18.37, respectively (diff. –8.89, 95%CI –10.11 to –9.67). Outpatient DDD/100 ambulatory visits was 67.68 vs. 86.20 (diff. –18.52, 95%CI –19.94 to –17.1), and hospital DDD/per 100 inpatient-days was 39.79 vs. 61.71 (diff. –21.92, 95%CI –26.2 to –17.68) for pandemic and pre-pandemic periods, respectively. During the pandemic period, an overall reduction in macrolides use was also observed (–3.13 DDD/100 ambulatory visits, 95%CI –3.84 to –2.44, and –2.05 DDD/per 100 inpatient-days, 95%CI –2.88 to –1.26). Additionally, an increase in Access antimicrobials (83.3% vs. 79.5%; diff. 3.8%, 95%CI 0.3% to 7.4%) and a reduction in the Watch group (16.7% vs. 20.5%; diff. –3.7%, 95%CI –7.4% to –0.1%) were observed for pandemic and pre-pandemic periods, respectively. Conclusion In this closed network, we observed a reduction in antibiotic use both in ambulatory and inpatient settings. Although, multifactorial, we believe the enhanced antibiotic stewardship approach on COVID-19 patients played a role in limiting antimicrobial use in this private healthcare system. Disclosures All Authors: No reported disclosures.

A correlated human red blood cell membrane fluctuation dependent on d-glucose concentration was found with dual time resolved membrane fluctuation spectroscopy (D-TRMFS). This new technique is a modified version of the dual optical tweezers method that has been adapted to measure the mechanical properties of red blood cells (RBCs) at distant membrane points simultaneously, enabling correlation analysis. Mechanical parameters under different d-glucose concentrations were obtained from direct membrane flickering measurements, complemented with membrane fluidity measurements using Laurdan Generalized Polarization (GP) Microscopy. Our results show an increase in the fluctuation amplitude of the lipid bilayer, and a decline in tension value, bending modulus and fluidity as d-glucose concentration increases. Metabolic mechanisms are proposed as explanations for the results.

The thermodynamic properties of pure compounds are relevant data for process systems engineering. Different first-order group contribution models have been reported in the literature to calculate these properties and they are also widely employed in commercial process simulators. However, they may have some limitations and, consequently, a reliable comparison of these models is required to analyze their performance and to determine the best alternative for the calculation of pure compound properties. This paper reports the implementation and evaluation of several first-order group contribution models to calculate the normal boiling point and critical properties (temperature, pressure, and volume) of pure compounds. The performance of these models was characterized and compared for several compound families using a standardized approach to determine their group contributions and parameters. An artificial neural network model was also applied and assessed to improve the estimations obtained with the best group contribution models. Results showed that the calculation of critical temperature was challenging for several compound families where AARD values ranged from 0.05 to 56.28%, while the group contribution models were more accurate to estimate the critical volume with AARD values ranging from 0.48 to 35.99%. This study allows us to identify the limitations and gaps of this type of thermodynamic models with the objective of improving its performance for the calculation of pure compound thermodynamic properties. The findings of this study can help to enhance the capabilities of thermodynamic models for the calculation of the normal boiling point and critical properties of pure compounds, which are relevant for the process systems engineering of new operations and products.

Spatial transcriptomics (ST) is transforming the way we can study gene expression and its regulation through position-specific resolution within tissues. However, as in bulk RNA-Seq, transposable elements (TEs) are not being studied due to their highly repetitive nature. In recent years, TEs have been recognized as important regulators of gene expression, and thus, TE expression analysis in a spatially resolved manner could further help to understand their role in gene regulation within tissues. We present SpatialTE, a tool to analyze TE expression from ST datasets and show its application in somatic and diseased tissues. The results indicate that TEs have spatially regulated expression patterns and that their expression profiles are spatially altered in ALS disease, indicating that TEs might perform differential regulatory functions within tissue organs. We have made SpatialTE publicly available as open-source software under an MIT license.

The submandibular gland (SG) is a relatively simple organ formed by three cell types: acinar, myoepithelial, and an intricate network of duct-forming epithelial cells, that together fulfills several physiological functions from assisting food digestion to acting as an immune barrier against pathogens. Successful SG organogenesis is the product of highly controlled and orchestrated genetic and transcriptional programs. Mounting evidence links Transposable Elements (TEs), originally thought to be selfish genetic elements, to different aspects of gene regulation in mammalian development and disease. To our knowledge, the role of TEs during murine SG organogenesis has not been studied. Using novel bioinformatic tools and publicly available RNA-Seq datasets, our results indicate that a significant number of genic and intergenic TEs are differentially expressed during the SG development. Furthermore, changes in expression of specific TEs correlated with that of genes involved in cellular division and differentiation, critical aspects for SG maturation. Altogether, we propose that TEs modulate gene networks that operate during SG development. Supplementary Information The online version contains supplementary material available at 10.1186/s13100-021-00251-1.

In mammals, the connections between motor neurons and muscle fibers profoundly reorganize in the early postnatal period. To better understand this synaptic rewiring we traced out all the connectivity in muscles at successive ages in the mouse using serial section scanning electron microscopy in a muscle at birth and Brainbow-based and XFP-based fluorescent reconstructions in neonatal and older muscles respectively. Our data indicate that axons prune about 85% of their branches in the first two weeks of postnatal life, and that while much of this pruning leaves neuromuscular junctions with only one remaining axon (a ∼8-fold reduction), it also causes a ∼6-fold reduction in the number of muscle fibers that possess more than one neuromuscular junction. Unexpectedly, the simplification of the wiring diagram was not haphazard but rather was constrained by the tendency for neurons to maintain co-innervation the longest with other neurons based on their proximity in an abstract rank order. This synaptic ordering preference was even significant at birth when connectivity was the most overlapping but became more striking as development proceeded and was even obvious in the few adult muscle fibers that retained more than one axon at different neuromuscular junctions. Analysis of properties of muscle fibers sharing axons at developing ages and changes in the physical distance between neuromuscular junctions that were maintained in young versus older muscles suggests that the rank order of motor neurons is based on their relative similarity in activity patterns. This same ranking governs both the close-proximity synaptic competitions within neuromuscular junctions and the long-distance competitions that remove or maintain synapses millimeters apart meaning that all neuromuscular rewiring is based on the same global activity ordering rule. We think it is likely that this ranking is related to the ultimate recruitment order of motor axon activity as first described by (Henneman, 1957). Thus the emerging structure of neuromuscular circuitry is a product of its function: initial nearly all-to-all connectivity gives rise to a well-organized system of axons, allowing for the orderly recruitment of neurons during a smoothly graded behavior.

SUMMARY: In vitro modeling of neurodegenerative diseases is now possible by using patient-derived induced pluripotent stem cells (iPS). Through them, it is nowadays conceivable to obtain human neurons and glia, and study diseases cellular and molecular mechanisms, an attribute that was previously unavailable to any human condition. Amyotrophic lateral sclerosis (ALS) is one of the diseases that has gained a rapid advance with iPS technology. By differentiating motor neurons from iPS cells of ALS- patients, we are studying the mechanisms underlying ALS- disease onset and progression. Here, we introduce a cellular platform to help maintain longevity of ALS iPS-motor neurons, a cellular feature relevant for most late-onset human diseases. Long term cultures of patient-derived iPS cells might prove to be critical for the development of personalized-drugs.

Our data proposes that glucose is transferred directly to the cerebrospinal fluid (CSF) of the hypothalamic ventricular cavity through a rapid "fast-track-type mechanism" that would efficiently stimulate the glucosensing areas. This mechanism would occur at the level of the median eminence (ME), a periventricular hypothalamic zone with no blood-brain barrier. This "fast-track" mechanism would involve specific glial cells of the ME known as β2 tanycytes that could function as "inverted enterocytes," expressing low-affinity glucose transporters GLUT2 and GLUT6 in order to rapidly transfer glucose to the CSF. Due to the large size of tanycytes, the presence of a high concentration of mitochondria and the expression of low-affinity glucose transporters, it would be expected that these cells accumulate glucose in the endoplasmic reticulum (ER) by sequestering glucose-6-phosphate (G-6-P), in a similar way to that recently demonstrated in astrocytes. Glucose could diffuse through the cells by micrometric distances to be released in the apical region of β2 tanycytes, towards the CSF. Through this mechanism, levels of glucose would increase inside the hypothalamus, stimulating glucosensing mechanisms quickly and efficiently. KEY MESSAGES: • Glucose diffuses through the median eminence cells (β2 tanycytes), towards the hypothalamic CSF. • Glucose is transferred through a rapid "fast-track-type mechanism" via GLUT2 and GLUT6. • Through this mechanism, hypothalamic glucose levels increase, stimulating glucosensing.

Although molecular dynamics simulations allow for the study of interactions among virtually all biomolecular entities, metal ions still pose significant challenges in achieving an accurate structural and dynamical description of many biological assemblies, particularly to coarse-grained (CG) models. Although the reduced computational cost of CG methods often makes them the technique of choice for the study of large biomolecular systems, the parameterization of metal ions is still very crude or not available for the vast majority of CG force fields. Here, we show that incorporating statistical data retrieved from the Protein Data Bank (PDB) to set specific Lennard-Jones interactions can produce structurally accurate CG molecular dynamics simulations using the SIRAH force field. We provide a set of interaction parameters for calcium, magnesium, and zinc ions, which cover more than 80% of the metal-bound structures reported in the PDB. Simulations performed on several proteins and DNA systems show that it is possible to preclude the use of topological constraints by modifying specific Lennard-Jones interactions.

A challenging aspect of neuroscience revolves around mapping the synaptic connections within neural circuits (connectomics) over scales spanning several orders of magnitude (nanometers to meters). Despite significant improvements in serial section electron microscopy (SSEM) technologies, several major roadblocks have impaired its general applicability to mammalian neural circuits. In the present study, we introduce a new approach that circumvents some of these roadblocks by adapting a genetically-encoded ascorbate peroxidase (APEX2) as a fusion protein to a membrane-targeted fluorescent reporter (CAAX-Venus), and introduce it in single pyramidal neurons in vivo using extremely sparse in utero cortical electroporation. This approach allows us to perform Correlated Light-SSEM (CoLSSEM), a variant of Correlated Light-EM (CLEM), on individual neurons, reconstructing their dendritic and axonal arborization in a targeted way via combination of high-resolution confocal microscopy, and subsequent imaging of its ultrastructural features and synaptic connections with ATUM-SEM (automated tape-collecting ultramicrotome - scanning electron microscopy) technology. Our method significantly will improve the feasibility of large-scale reconstructions of neurons within a circuit, and permits the description of some ultrastructural features of identified neurons with their functional and/or structural connectivity, one of the main goal of connectomics.

Although molecular dynamics simulations allow for the study of interactions among virtually all biomolecular entities, metal ions still pose significant challenges to achieve an accurate structural and dynamical description of many biological assemblies. This is particularly the case for coarse-grained (CG) models. Although the reduced computational cost of CG methods often makes them the technique of choice for the study of large biomolecular systems, the parameterization of metal ions is still very crude or simply not available for the vast majority of CG- force fields. Here, we show that incorporating statistical data retrieved from the Protein Data Bank (PDB) to set specific Lennard-Jones interactions can produce structurally accurate CG molecular dynamics simulations. Using this simple approach, we provide a set of interaction parameters for Calcium, Magnesium, and Zinc ions, which cover more than 80% of the metal-bound structures reported on the PDB. Simulations performed using the SIRAH force field on several proteins and DNA systems show that using the present approach it is possible to obtain non-bonded interaction parameters that obviate the use of topological constraints.

The coordinated movement of organisms relies on efficient nerve-muscle communication at the neuromuscular junction. After peripheral nerve injury or neurodegeneration, motor neurons and Schwann cells increase the expression of the p75NTRpan-neurotrophin receptor. Even though p75NTRtargeting has emerged as a promising therapeutic strategy to delay peripheral neuronal damage progression, the effects of long-term p75NTRinhibition at the mature neuromuscular junction have not been elucidated. We performed quantitative neuroanathomical analyses of the neuromuscular junction in p75NTRnull mice by laser confocal and electron microscopy, which were complemented with electromyography, locomotor tests, and pharmacological intervention studies. Mature neuromuscular synapses of p75NTRnull mice show impaired postsynaptic organization and ultrastructural complexity, which correlate with altered synaptic function at the levels of nerve activity-induced muscle responses, muscle fiber structure, force production, and locomotor performance. Our results on primary myotubes and denervated muscles indicate that muscle-derived p75NTRdoes not play a major role on postsynaptic organization. In turn, motor axon terminals of p75NTRnull mice display a strong reduction in the number of synaptic vesicles and active zones. According to the observed pre and postsynaptic defects, pharmacological acetylcholinesterase inhibition rescued nerve-dependent muscle response and force production in p75NTRnull mice. Our findings revealing that p75NTRis required to organize mature neuromuscular junctions contribute to a comprehensive view of the possible effects caused by therapeutic attempts to target p75NTR.

A heterogeneous physical model with two bindings sites (HPMTBS) was successfully used to explain the adsorption of Cd2+, Ni2+, Zn2+, and Cu2+ ions on flamboyant pods functionalized with citric acid. Experimental results and statistical physics modeling showed that carboxylic and phenolic functionalities of this adsorbent played a relevant role for the adsorption of Cd2+, Ni2+, Zn2+, and Cu2+ ions. Calculations performed with HPMTBS suggested that the removal of these cations was a multi-ionic adsorption process at tested operating conditions. This adsorbent was more effective to remove Cd2+, Ni2+, Zn2+ and Cu2+ ions at high solution temperatures thus indicating an endothermic process with adsorption energies ranging from 20.3 to 29.5 kJ/mol, which were associated to physisorption. The total adsorption capacities varied from 0.10 to 0.32, 0.28 to 0.39, 0.19 to 0.25 and 0.20 to 0.31 mmol/g for Cd2+, Ni2+, Zn2+ and Cu2+, respectively. This difference in adsorption capacities could be attributed to the ionic radius of tested adsorbates. This functionalized biomass can be considered as an alternative adsorbent for facing water pollution by heavy metal ions.

This paper provides a detailed analysis of the recycling of Tetra Pak waste via pyrolysis to recover the most valuable solid products within its composition, char and aluminum, and the subsequent application of the char in the adsorption of mercury in aqueous solutions. The impact of the Tetra Pak pyrolysis conditions on the char and aluminum yields and their associated properties have been analyzed using a variety of physico-chemical techniques. Tetra Pak-derived chars showed outstanding mercury adsorption properties (up to 215.7 mg/g) that can be attributed to the heterogeneous surface chemistry composed mainly by oxygenated functional groups associated to C, Ca, Al and Si. Tetra Pak pyrolysis allowed an effective recovery of aluminum at pyrolysis temperatures of 600 and 800 °C. Higher temperatures, up to 1000 °C, promote its oxidation to aluminum oxide and hydroxide. These findings contribute to increase the versatility in the Tetra Pak reuse to develop new adsorbents with promising performance for water treatment and the associated recovery of aluminum for further industrial applications. This work was supported by Junta de Extremadura and Fondo Europeo para el Desarrollo Regional (GRU18035). JSA would like to acknowledge financial support from MINECO (projects MAT2016-80285-p & PID2019-108453GB-C21).

Involuntary choreiform movements are clinical hallmark of Huntington's disease, an autosomal dominant neurodegenerative disorder caused by an increased number of CAG trinucleotide repeats in the huntingtin gene. Involuntary movements start with an impairment of facial muscles and then affect trunk and limbs muscles. Huntington's disease symptoms are caused by changes in cortex and striatum neurons induced by mutated huntingtin protein. However, little is known about the impact of this abnormal protein in spinal cord motoneurons that control movement. Therefore, in this study we evaluated abnormalities in the motor unit (spinal cervical motoneurons, motor axons, neuromuscular junctions and muscle) in a mouse model for Huntington's disease (BACHD). Using light, fluorescence, confocal, and electron microscopy, we showed significant changes such as muscle fibers atrophy, fragmentation of neuromuscular junctions, axonal alterations, and motoneurons death in BACHD mice. Noteworthy, the surviving motoneurons from BACHD spinal cords were smaller than WT. We suggest that this loss of larger putative motoneurons is accompanied by a decrease in the expression of fast glycolytic muscle fibers in this model for Huntington's disease. These observations show spinal cord motoneurons loss in BACHD that might help to understand neuromuscular changes in Huntington's disease.

Mutations in autophagy genes can cause familial and sporadic amyotrophic lateral sclerosis (ALS). However, the role of autophagy in ALS pathogenesis is poorly understood, in part due to the lack of cell type-specific manipulations of this pathway in animal models. Using a mouse model of ALS expressing mutant superoxide dismutase 1 (SOD1G93A), we show that motor neurons form large autophagosomes containing ubiquitinated aggregates early in disease progression. To investigate whether this response is protective or detrimental, we generated mice in which the critical autophagy gene Atg7 was specifically disrupted in motor neurons (Atg7 cKO). Atg7 cKO mice were viable but exhibited structural and functional defects at a subset of vulnerable neuromuscular junctions. By crossing Atg7 cKO mice to the SOD1G93A mouse model, we found that autophagy inhibition accelerated early neuromuscular denervation of the tibialis anterior muscle and the onset of hindlimb tremor. Surprisingly, however, lifespan was extended in Atg7 cKO; SOD1G93A double-mutant mice. Autophagy inhibition did not prevent motor neuron cell death, but it reduced glial inflammation and blocked activation of the stress-related transcription factor c-Jun in spinal interneurons. We conclude that motor neuron autophagy is required to maintain neuromuscular innervation early in disease but eventually acts in a non–cell-autonomous manner to promote disease progression.

This study reports the application of a neural network approach for modeling and analyzing the sorption performance of different lignocellulosic wastes, namely jacaranda fruit, plum kernels, and nu...

SummaryIndividual mammalian neurons stochastically express distinct repertoires of α, β, and γ protocadherin (Pcdh) proteins, which function in neural circuit assembly. We report that all three subfamilies of clustered Pcdhs can engage in specific homophilic interactions, that cell surface delivery of Pcdhα isoforms requires cis interactions with other Pcdhs, and that the extracellular cadherin domain EC6 plays a critical role in this process. Examination of homophilic interactions between specific combinations of multiple Pcdh isoforms revealed that Pcdh combinatorial recognition specificities depend on the identity of all of the expressed isoforms. A single mismatched Pcdh isoform can interfere with these combinatorial homophilic interactions. A theoretical analysis reveals that assembly of Pcdh isoforms into multimeric recognition units and the observed tolerance for mismatched isoforms can generate cell surface diversity sufficient for single-cell identity. However, the competing demands of nonself discrimination and self-recognition place limitations on the mechanisms by which homophilic recognition units can function.

In this study, the design and construction of an extrusion equipment with spinning fiber devices has been developed to produce polyester fiber from virgin and recycled polyethylene terephthalate (PET). Several operating parameters (i.e., pressure, temperature, feed flow rate, extrusion speed and extruder design) have been analyzed to identify the best process conditions. In particular, this study has focused on a detailed analysis for the processing of recycled raw material for polyester textile fiber applications considering the variability of the process and identifying alternatives to minimize the impact on the quality parameters such as the fiber diameter and mechanical specifications. The experimental results were compared with the values calculated using a theoretical model, which has been developed for these particular cases. The mathematical analysis of the mass flow showed a very good agreement with respect to the experimental data, where there was a percentage difference < 3 %. It was found that the fiber diameter is a function of intrinsic viscosity (VI) or melt flow index (MFI). Finally, the mechanical properties of the fibers were evaluated and results indicated that the fiber with higher average molecular weight showed higher tenacity and lower Young’s modulus values.

In many parts of the nervous system, signals pass across multiple synaptic relays on their way to a destination, but little is known about how these relays form and the function they serve. To get some insight into this question we ask how the connectivity patterns are organized at two successive synaptic relays in a simple, cholinergic efferent pathway. We found that the organization at successive relays in the parasympathetic nervous system strongly resemble each other despite the different embryological origin and physiological properties of the pre- and postsynaptic cells. Additionally, we found a similar developmental synaptic pruning and elaboration strategy is used at both sites to generate their adult organizations. The striking parallels in adult innervation and developmental mechanisms at the relays argue that a general strategy is in operation. We discuss why from a functional standpoint this structural organization may amplify central signals while at the same time maintaining positional targeting. DOI: http://dx.doi.org/10.7554/eLife.23193.001

SummaryThe mammalian Protocadherin (Pcdh) alpha, beta, and gamma gene clusters encode a large family of cadherin-like transmembrane proteins that are differentially expressed in individual neurons. The 22 isoforms of the Pcdhg gene cluster are diversified into A-, B-, and C-types, and the C-type isoforms differ from all other clustered Pcdhs in sequence and expression. Here, we show that mice lacking the three C-type isoforms are phenotypically indistinguishable from the Pcdhg null mutants, displaying virtually identical cellular and synaptic alterations resulting from neuronal apoptosis. By contrast, mice lacking three A-type isoforms exhibit no detectable phenotypes. Remarkably, however, genetically blocking apoptosis rescues the neonatal lethality of the C-type isoform knockouts, but not that of the Pcdhg null mutants. We conclude that the role of the Pcdhg gene cluster in neuronal survival is primarily, if not specifically, mediated by its C-type isoforms, whereas a separate role essential for postnatal development, likely in neuronal wiring, requires isoform diversity.

Summary Using light and serial electron microscopy, we show profound refinements in motor axonal branching and synaptic connectivity before and after birth. Embryonic axons become maximally connected just before birth when they innervate ∼10-fold more muscle fibers than in maturity. In some developing muscles, axons innervate almost every muscle fiber. At birth, each neuromuscular junction is coinnervated by approximately ten highly intermingled axons (versus one in adults). Extensive die off of terminal branches occurs during the first several postnatal days, leading to much sparser arbors that still span the same territory. Despite the extensive pruning, total axoplasm per neuron increases as axons elongate, thicken, and add more synaptic release sites on their remaining targets. Motor axons therefore initially establish weak connections with nearly all available postsynaptic targets but, beginning at birth, massively redistribute synaptic resources, concentrating many more synaptic sites on many fewer muscle fibers. Analogous changes in connectivity may occur in the CNS. Video Abstract

Conventional heavy metal poststaining methods on thin sections lend contrast but often cause contamination. To avoid this problem, we tested several en bloc staining techniques to contrast tissue in serial sections mounted on solid substrates for examination by field emission scanning electron microscopy (FESEM). Because FESEM section imaging requires that specimens have higher contrast and greater electrical conductivity than transmission electron microscopy (TEM) samples, our technique uses osmium impregnation (OTO) to make the samples conductive while heavily staining membranes for segmentation studies. Combining this step with other classic heavy metal en bloc stains, including uranyl acetate (UA), lead aspartate, copper sulfate and lead citrate, produced clean, highly contrasted TEM and scanning electron microscopy (SEM) samples of insect, fish and mammalian nervous systems. This protocol takes 7-15 d to prepare resin-embedded tissue, cut sections and produce serial section images.

Huntington’s disease (HD) is a disorder characterized by chronic involuntary movements, dementia, and psychiatric symptoms. It is caused by a mutation in the gene that encodes for huntingtin protein (HTT), leading to the formation of mutant proteins expressed in various tissues. Although brain pathology has become the hallmark for HD, recent studies suggest that damage of peripheral structures also contributes to HD progression. We previously identified severe alterations in the motor units that innervate cervical muscles in 12-month-old BACHD (Bacterial Artificial Chromosome Huntington’s Disease) mice, a well-established mouse model for HD. Here, we studied lumbar motoneurons and their projections onto hind limb fast-twitch skeletal muscles (tibialis anterior), which control balance and gait in HD patients. We found that lumbar motoneurons were altered in the HD mouse model; the number and size of lumbar motoneurons were reduced in BACHD. Structural alterations were also present in the sciatic nerve and neuromuscular junctions. Acetylcholine receptors were organized in several small patches (acetylcholine receptor fragmentation), many of which were partially innervated. In BACHD mice, we observed atrophy of tibialis anterior muscles, decreased expression of glycolytic fast Type IIB fibers, and at the ultrastructural level, alterations of sarcomeres and mitochondria. Corroborating all these findings, BACHD animals performed worse on motor behavior tests. Our results provide additional evidences that nerve–muscle communication is impaired in HD and that motoneurons from distinct spinal cord locations are similarly affected in the disease.

In this study, we report the application of performance profiles to compare the numerical behavior of the Simulated Annealing and Very Fast Simulated Annealing methods in thermodynamic calculations for process modeling. Specifically, the reliability and efficiency of these stochastic optimization methods have been compared using global optimization problems related to phase stability and equilibrium calculations in non-reactive systems, the prediction of homogeneous azeotropes and the parameter estimation in thermodynamic models. Our results indicate that the Simulated Annealing is more robust to solve these global optimization problems; however, this method is less efficient than the Very Fast Simulated Annealing.

During injury to the nervous system, innate immune cells mediate phagocytosis of debris, cytokine production, and axon regeneration. In the neuro-degenerative disease amyotrophic lateral sclerosis (ALS), innate immune cells in the CNS are activated. However, the role of innate immunity in the peripheral nervous system (PNS) has not been well defined. In this study, we characterized robust activation of CD169/CD68/Iba1+ macrophages throughout the PNS in mutant SOD1 G93A and SOD1 G37R transgenic mouse models of ALS. Macrophage activation occurred pre-symptomatically, and expanded from focal arrays within nerve bundles to a tissue-wide distribution following symptom onset. We found a striking dichotomy for immune cells within the spinal cord and PNS. Flow cytometry and GFP bone marrow chimeras showed that spinal cord microglia were mainly tissue resident derived, dendritic-like cells, whereas in peripheral nerves, the majority of activated macrophages infiltrated from the circulation. Humoral antibodies and complement localized to PNS tissue in tandem with macrophage recruitment, and deficiency in complement C4 led to decreased macrophage activation. Therefore, cross-talk between nervous and immune systems occurs throughout the PNS during ALS disease progression. These data reveal a progressive innate and humoral immune response in peripheral nerves that is separate and distinct from spinal cord immune activation in ALS transgenic mice.

Mutations in FUS cause amyotrophic lateral sclerosis (ALS), including some of the most aggressive, juvenile-onset forms of the disease. FUS loss-of-function and toxic gain-of-function mechanisms have been proposed to explain how mutant FUS leads to motor neuron degeneration, but neither has been firmly established in the pathogenesis of ALS. Here we characterize a series of transgenic FUS mouse lines that manifest progressive, mutant-dependent motor neuron degeneration preceded by early, structural and functional abnormalities at the neuromuscular junction. A novel, conditional FUS knockout mutant reveals that postnatal elimination of FUS has no effect on motor neuron survival or function. Moreover, endogenous FUS does not contribute to the onset of the ALS phenotype induced by mutant FUS. These findings demonstrate that FUS-dependent motor degeneration is not due to loss of FUS function, but to the gain of toxic properties conferred by ALS mutations., The mechanism by which FUS mutations cause familial ALS remains unclear. Here, the authors use mouse transgenic models to show that a toxic gain-of-function underlies motor neuron degeneration, and that the toxicity of mutant FUS does not depend on a loss or excess of FUS activity.

According to the World Energy Council (WEC) the estimated energy of the wave power in the world is in the range of 8,000 to 80,000 TWh/year to depths of 100 meters or higher and actually the utilization of wave energy resource it is possible because it has been implemented in countries like Australia, Indonesia, Nigeria, United Kingdom, Norway, Portugal and Colombia evaluating different types of marine technologies that take the advantage of the kinetic energy in the ocean waves. Mexico according to the National Institute of Statistics and Information (INEGI) has a land area of 1,972,550 km2 of which has a coastline of 11,150 km having potential for the use of their coasts. Baja California with a land area of 71,445 km2 (3.6% of the country) is located on a peninsula in northwest Mexico and has 720 km of coastline on the Pacific Ocean (6.4% nationally) with a range of depths of 25.6 m to 650 m at a distance of the coastline of 15 km, which makes it suitable to evaluate the use of wave energy at local sites. With the completion of this work will contribute to the characterization of the sites that will present the best technical and economic conditions for its implementation, considering the physical characteristics of the site as well as connection points on the transmission lines operated by the Federal Electricity Commission (CFE). For the preparation of this study was carried out in three stages: a) Site Selection, b) Evaluation of Wave Energy and c) Economic evaluation of sites using RETScreen. Based on the characteristics of the coast of Baja California the results obtained are the following: 1) 18 sites were selected with a sea depth averaged of 50 m, the annual density power was 7.5 kW/m, this represents a potential of 210 MW considering an average length of 2 km in each site, 2) The economic evaluation of this type of project was for a period of 30 years in RETScreen, considers an annual inflation rate of 5% and obtains an investment cost of 9,538 US $/kW for this type of generation. We conclude that this source of energy will reduce dependence on fossil fuels and contribute to the generation of electricity in the state of Baja California diversifying the energetic matrix state by the use of clean and renewable sources, which represents an investment opportunity between the public and private sector.

We report that mice lacking the heterogeneous nuclear ribonucleoprotein U (hnRNP U) in the heart develop lethal dilated cardiomyopathy and display numerous defects in cardiac pre-mRNA splicing. Mutant hearts have disorganized cardiomyocytes, impaired contractility, and abnormal excitation-contraction coupling activities. RNA-seq analyses of Hnrnpu mutant hearts revealed extensive defects in alternative splicing of pre-mRNAs encoding proteins known to be critical for normal heart development and function, including Titin and calcium/calmodulin-dependent protein kinase II delta (Camk2d). Loss of hnRNP U expression in cardiomyocytes also leads to aberrant splicing of the pre-mRNA encoding the excitation-contraction coupling component Junctin. We found that the protein product of an alternatively spliced Junctin isoform is N-glycosylated at a specific asparagine site that is required for interactions with specific protein partners. Our findings provide conclusive evidence for the essential role of hnRNP U in heart development and function and in the regulation of alternative splicing.

La presente tesis documenta la instrumentación y las estrategias de control implementadas en un deshidratador de frutas y hortalizas. El objetivo principal de la tesis consistió en determinar la estrategia de control que permite alcanzar las condiciones de deshidratado al menor costo energético, por lo que se planteó el comparar un controlador difuso y un control neuronal. Ambos controles fueron implementados en Python para ser ejecutados en un sistema embebido con sistema operativo basado en el kernel de Linuxel cual realiza las acciones de sincronización con las terminales remotas con capacidad de monitoreo y control. El sistema cuenta con una interfaz web para consultar el estado actual y pasado del sistema así como para modificar los parámetros de control. This thesis documents the instrumentation and control strategies implemented in dehydrator of fruits and vegetables. The main aim of the thesis was determine the better control strategy that achieves the dehydrated condition stolower energy cost, so that was raised comparing a fuzzy controller and neural control. Both controls were implemented in Pythonto run on an embedded device with operating system based onLinux kernel that performs the actions of sync with the remote terminal capable of monitoring and control. The system has a web interface to query the current state.

We describe an image processing tool for helping to organize, annotate and map neuronal circuitry. The tools use high-resolution images serially acquired via scanning electron microscopy (SEM). First, various image processing filters are applied to the serial images to automatically sort and stitch them. In a second step, images are aligned, equalized and filtered to generate 3D volumetric image stacks. Finally, within the 3D volume, the neural processes selected by the user are automatically segmented via parallel programming. Thus, the tool renders a model in which pre- and postsynaptic elements become identified in a connectivity matrix.