Tight Loop Research Articles

Spinal motoneuron excitability is homeostatically-regulated through β-adrenergic neuromodulation in wild-type and presymptomatic SOD1 mice.

Homeostatic feedback loops are essential to stabilize the activity of neurons and neuronal networks. It has been hypothesized that, in the context of Amyotrophic Lateral Sclerosis (ALS), an excessive gain in feedback loops might hyper- or hypo-excite motoneurons (MNs) and contribute to the pathogenesis. Here, we investigated how the neuromodulation of MN intrinsic properties is homeostatically controlled in presymptomatic adult SOD1(G93A) mice and in the age-matched control WT mice. First, we determined that β2 and β3- adrenergic receptors, which are Gs-coupled receptors and subject to tight and robust feedback loops, are specifically expressed in spinal MNs of both SOD1 and WT mice at P45. We then demonstrated that these receptors elicit a so-far overlooked neuromodulation of the firing and excitability properties of MNs. These electrical properties are homeostatically regulated following receptor engagement, which triggers ion channel transcriptional changes and downregulates those receptors. These homeostatic feedbacks are not dysregulated in presymptomatic SOD1 mice, and they set the MN excitability upon β-adrenergic neuromodulation.

Simple (yet Efficient) Function Authoring for Vectorized Engines

Vectorized execution engines process large datasets by decomposing computations into concise (tight) loops, which can be more efficiently executed by modern hardware. Providing loops that are optimal for execution usually adds burden to the software development process, as developers are required to understand details of vectorized execution, columnar data layout, data encodings, and the code compilation process itself, presenting a steep learning curve and challenges to organizations building and scaling large engineering teams. Due to their large quantity, scalar function authoring accentuates this problem. In our experience building the Velox open source execution engine, we have observed that exposing a large number of developers to the complexity inherent to vectorization resulted in a disproportionate amount of bugs and performance inefficiencies. In this paper, we describe the simple function interface (SFI) created to address this issue. SFI highly simplifies scalar function authoring by encapsulating the vectorization complexity required to generate tight loops, and presenting developers with a simpler, conciser, and more natural row-based interface - without sacrificing performance. SFI also hides columnar layout details, while providing developers the flexibility to efficiently implement advanced features such as functions with nested and recursive parameter types, type variables, variadic parameters, and generic types. Today, more than a thousand functions have been added to Velox using the SFI, implementing popular open source SQL dialects and internal domain-specific use cases at Meta, and are in active production use. While this paper presents implementation details, performance pitfalls, experimental results, and our overall experience developing the state-of-the-art Velox vectorized execution engine, we believe the concepts and trade-offs to be fundamentally equivalent and generally applicable to other vectorized engines.

Comparing the impact of different adsorbed layers on the local glass transition of polymer matrices.

Chain adsorption to nanofiller interfaces creating bound layers has become central to understanding property changes in polymer nanocomposites. We determine the impact different kinds of adsorbed layers can have on the local glass transition temperature Tg of polymer matrices in a model film system using a localized fluorescence method. This work compares the adsorption and desorption of adsorbed layers grown in solution with the solution washing characteristics of adsorbed layers formed in the melt, leveraging knowledge about polymer adsorption in solution to infer the structure of adsorbed layers formed in the melt. In the limit of zero concentration after a long time in solution, we find that both kinds of adsorbed layers reach the same limiting adsorbed amount h∞(c → 0) ≈ 1 nm, appearing to evolve to the same thermodynamic equilibrium state of a near monolayer of surface coverage. We propose that melt annealing leads to a coarsening of polymer segment-surface contacts, increasing the length of trains and shrinking loops and tails, slowing the subsequent kinetics of these adsorbed chains in solution. Considering how the pyrene-labeled chains intermix with the adsorbed layer enables us to discriminate between the impact of tails, loops, and trains as threading of loops takes longer. We find that large fluffy loops, tails, and trains have little to no impact on the local Tg. A large 30K increase in local Tg is observed for 30-minsolvent washed well-annealed films at long intermixing times that we attribute to the threading of small tight loops.

Response and damage mechanism of carbon/aramid intra-ply hybrid weft-knitted reinforced composites under low-velocity impact

Response and damage mechanism of carbon/aramid intra-ply hybrid weft-knitted reinforced composites under low-velocity impact

Motile Living Biobots Self-Construct from Adult Human Somatic Progenitor Seed Cells.

Fundamental knowledge gaps exist about the plasticity of cells from adult soma and the potential diversity of body shape and behavior in living constructs derived from genetically wild-type cells. Here anthrobots are introduced, a spheroid-shaped multicellular biological robot (biobot) platform with diameters ranging from 30 to 500microns and cilia-powered locomotive abilities. Each Anthrobot begins as a single cell, derived from the adult human lung, and self-constructs into a multicellular motile biobot after being cultured in extra cellular matrix for 2 weeks and transferred into a minimally viscous habitat. Anthrobots exhibit diverse behaviors with motility patterns ranging from tight loops to straight lines and speeds ranging from 5-50micronss-1 . The anatomical investigations reveal that this behavioral diversity is significantly correlated with their morphological diversity. Anthrobots can assume morphologies with fully polarized or wholly ciliated bodies and spherical or ellipsoidal shapes, each related to a distinct movement type. Anthrobots are found to be capable of traversing, andinducing rapid repair of scratches in, cultured human neural cell sheets in vitro. By controlling microenvironmental cues in bulk, novel structures, with new and unexpected behavior and biomedically-relevant capabilities, can be discovered in morphogenetic processes without direct genetic editing or manual sculpting.

Partition of the space of planar quintic Pythagorean-hodograph curves

Partition of the space of planar quintic Pythagorean-hodograph curves

Cytosolic and mitochondrial translation elongation are coordinated through the molecular chaperone TRAP1 for the synthesis and import of mitochondrial proteins.

A complex interplay between mRNA translation and cellular respiration has been recently unveiled, but its regulation in humans is poorly characterized in either health or disease. Cancer cells radically reshape both biosynthetic and bioenergetic pathways to sustain their aberrant growth rates. In this regard, we have shown that the molecular chaperone TRAP1 not only regulates the activity of respiratory complexes, behaving alternatively as an oncogene or a tumor suppressor, but also plays a concomitant moonlighting function in mRNA translation regulation. Herein, we identify the molecular mechanisms involved, showing that TRAP1 (1) binds both mitochondrial and cytosolic ribosomes, as well as translation elongation factors; (2) slows down translation elongation rate; and (3) favors localized translation in the proximity of mitochondria. We also provide evidence that TRAP1 is coexpressed in human tissues with the mitochondrial translational machinery, which is responsible for the synthesis of respiratory complex proteins. Altogether, our results show an unprecedented level of complexity in the regulation of cancer cell metabolism, strongly suggesting the existence of a tight feedback loop between protein synthesis and energy metabolism, based on the demonstration that a single molecular chaperone plays a role in both mitochondrial and cytosolic translation, as well as in mitochondrial respiration.

Hepatocyte apical bulkheads provide a mechanical means to oppose bile pressure.

Hepatocytes grow their apical surfaces anisotropically to generate a 3D network of bile canaliculi (BC). BC elongation is ensured by apical bulkheads, membrane extensions that traverse the lumen and connect juxtaposed hepatocytes. We hypothesize that apical bulkheads are mechanical elements that shape the BC lumen in liver development but also counteract elevated biliary pressure. Here, by resolving their structure using STED microscopy, we found that they are sealed by tight junction loops, connected by adherens junctions, and contain contractile actomyosin, characteristics of mechanical function. Apical bulkheads persist at high pressure upon microinjection of fluid into the BC lumen, and laser ablation demonstrated that they are under tension. A mechanical model based on ablation results revealed that apical bulkheads double the pressure BC can hold. Apical bulkhead frequency anticorrelates with BC connectivity during mouse liver development, consistent with predicted changes in biliary pressure. Our findings demonstrate that apical bulkheads are load-bearing mechanical elements that could protect the BC network against elevated pressure.

Dynamic analysis and experiment of chaotic circuit of non-homogeneous fractional memristor with bias voltage source

A physical memristor has an asymmetric tight hysteresis loop. In order to simulate the asymmetric tight hysteresis curve of the physical memristor more conveniently, a fractional-order diode bridge memristor model with a bias voltage source is proposed in this paper, which can continuously regulate the hysteresis loop. Firstly, based on fractional calculus theory, a fractional order model of a diode bridge memristor with a bias voltage source is established, and its electrical characteristics are analyzed. Secondly, by integrating it with the Jerk chaotic circuit, a non-homogeneous fractional order memristor chaotic circuit model with a bias voltage source is established, and the influence of bias voltage on its system dynamic behavior is studied. Once again, a fractional-order equivalent circuit model is built in PSpice and validated through circuit simulation. The experimental results are basically consistent with the numerical simulation results. Finally, the experiments on the circuit are completed in LabVIEW to validate the correctness and feasibility of the theoretical analysis. The results indicate that the fractional order memristor with bias voltage source can continuously obtain asymmetric tight hysteresis loop by adjusting the voltage of the bias voltage source. As the bias power supply voltage changes, the non-homogeneous fractional order memristor chaotic system exhibits that the period doubling bifurcation turns into chaos due to the symmetry breaking.

Partial Transection of the External Ear Caused by a Mask Worn for COVID-19 Protection

Introduction. During the COVID-19 pandemic surgical mask-wearing was widely adopted as a means of preventing infections, but there have been several reports of mask-induced skin problems. In this report, we describe a case in which surgery was required for a mask-induced ear injury. Case Report. An otherwise healthy 63-year-old male presented to the plastic surgery department with an auricle injury. He had been using a mask that was too small for his face for more than 1 month; the tight ear loops caused the upper part of his left auricle to begin to dissect, resulting in a large tear. More than a third of the left upper auricle was torn, and the wound surface was epithelialized. The patient had no history of skin disease or psychiatric disorder but was engaged in a job that required wearing a helmet constantly. Surgery was performed to refresh the epithelialized wound surface and suture it, and the patient healed without complication. Conclusion. While mask-wearing mandates and recommendations have considerably eased since the height of the pandemic, the current authors’ experience has brought to light problems related to mask usage. Thus, efforts should be made to investigate the causes of these problems and provide appropriate advice.

Towards fast-charging high-energy lithium-ion batteries: From nano- to micro-structuring perspectives

• Physicochemical fundamentals in electrochemical reactions were summarized in lithium-ion battery systems. • Charge transport effects in high-energy batteries were discussed and analyzed via numerical simulations. • Recent efforts from nano- to micro-structuring for advanced battery electrodes were reviewed. • A feedback loop among structure engineering, characterization and simulation was proposed. Electric vehicles (EVs) have been playing an indispensable role in reducing greenhouse gas emissions for our modern society. However, current EVs are difficult to meet people’s diverse travel needs, especially in long endurance and fast-charging capacities. At the heart of this issue is the physicochemical limit of current lithium-ion batteries (LIBs), which are the core parts for powering the vehicles. Hence, LIBs with simultaneous high energy and power are critically required to further promote the development of EVs. In this review, we first summarize the key electrochemical processes in electrochemical reactions which lead to the corresponding overpotentials in or between multiple battery components. Furthermore, numerical simulations are employed to quantitatively analyze the effects of versatile electrode parameters on electrochemical properties in high-energy NMC811//graphite systems. On the basis of the in-depth understandings from simulation, recent experimental efforts on designing electroactive materials and electrode architectures across multiple length scales are discussed. Among them, nano-structuring can promote local mass transport and stabilize the interfaces at the particle-level, while micro-structuring can establish efficient pathways for charge carriers at the electrode-level. Finally, we conclude that a tight feedback loop among structure engineering, characterization and simulation should be followed to speed up the understanding of the deficiencies existing in current electrode designs as well as point out the possible electrode optimization routes for next-generation fast-charging LIBs.

Calcium, Its Regulatory Hormones, and Their Causal Role on Blood Pressure: A Two-Sample Mendelian Randomization Study.

Vitamin D (Vit-D), parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23) are the major calciotropic hormones involved in the regulation of blood calcium levels from the intestine, kidney, and bone through a tight endocrine feedback loop system. Altered levels of calcium itself or through the effect of its regulatory hormones could affect blood pressure (BP), but the exact mechanisms remain unclear. To evaluate whether a causal relationship exists between serum calcium level and/or the regulatory hormones involved in its homeostasis with BP, we performed a two-sample Mendelian randomization (MR) study. From 4 large genome-wide association studies (GWAS) we obtained independent (r2 < 0.001) single nucleotide polymorphisms (SNPs) associated with serum calcium (119 SNPs), Vit-D (78 SNPs), PTH (5 SNPs), and FGF23 (5 SNPs), to investigate through MR their association with systolic BP (SBP) and diastolic BP (DBP) in a Swedish urban-based study, the Malmö Diet and Cancer study (n = 29 298). Causality was evaluated by the inverse variance weighted method (IVW) and weighted median, while MR Egger and MR-PRESSO were used as sensitivity analyses. Genetically predicted serum calcium level was found to be associated with DBP (IVW: beta = 0.10, SE = 0.04, P = 0.007) and SBP (IVW: beta = 0.07, SE = 0.04, P = 0.04). Genetically predicted Vit-D and PTH showed no association with the traits, while FGF23 was inversely associated with SBP (IVW: beta = -0.11, SE = 0.04, P = 0.01), although this association lost statistical significance in sensitivity analysis. Our study shows a direct association between genetically predicted calcium level and DBP, and a weaker association with SBP. No such clear association was found for genetically predicted calciotropic hormone levels. It is of interest to detect which target genes involved in calcium homeostasis mediate the effect of calcium on BP, particularly for improving personalized intervention strategies.

Long-range enhancement of N501Y-endowed mouse infectivity of SARS-CoV-2 by the non-RBD mutations of Ins215KLRS and H655Y

BackgroundRodents, such as mice, are vulnerable targets, and potential intermediate hosts, of SARS-CoV-2 variants of concern, including Alpha, Beta, Gamma, and Omicron. N501Y in the receptor-binding domain (RBD) of Spike protein is the key mutation dictating the mouse infectivity, on which the neighboring mutations within RBD have profound impacts. However, the impacts of mutations outside RBD on N501Y-mediated mouse infectivity remain to be explored.ResultsHerein, we report that two non-RBD mutations derived from mouse-adapted strain, Ins215KLRS in the N-terminal domain (NTD) and H655Y in the subdomain linking S1 to S2, enhance mouse infectivity in the presence of N501Y mutation, either alone or together. This is associated with increased interaction of Spike with mouse ACE2 and mutations-induced local conformation changes in Spike protein. Mechanistically, the H655Y mutation disrupts interaction with N657, resulting in a less tight loop that wraps the furin-cleavage finger; and the insertion of 215KLRS in NTD increases its intramolecular interaction with a peptide chain that interfaced with the RBD-proximal region of the neighboring protomer, leading to a more flexible RBD that facilitates receptor binding. Moreover, the Omicron Spike that contains Ins214EPE and H655Y mutations confer mouse infectivity > 50 times over the N501Y mutant, which could be effectively suppressed by mutating them back to wild type.ConclusionsCollectively, our study sheds light on the cooperation between distant Spike mutations in promoting virus infectivity, which may undermine the high infectiousness of Omicron variants towards mice.

THE CAUSAL ROLE OF SERUM CALCIUM, PTH AND FGF23 ON BLOOD PRESSURE: A TWO-SAMPLE MENDELIAN RANDOMIZATION

Objective: Parathyroid hormone (PTH) and Fibroblast Growth Factor 23 (FGF23) are among the calciotropic hormones involved in the regulation of blood calcium levels among the intestine, kidney, and bone through a tight endocrine feedback loop system. Altered levels of each of them could affect blood pressure either independently or not by the calcium, but the exact mechanisms remain unclear. To evaluate whether a causal relationship exists between serum calcium level and its homeostasis’ regulatory hormones with blood pressure traits, we performed a Two-Sample Mendelian Randomization. Design and method: From three large genome-wide association studies (GWAS) we obtained independent (r2 &lt; 0.001) and GWAS-significant (p &lt; 5X10-8) single nucleotide polymorphisms (SNPs) associated with serum calcium level (120 SNPs), PTH (5 SNPs), and FGF23 (5 SNPs), to investigate through MR their association with Systolic (SBP) and Diastolic (DBP) blood pressure in a Swedish large-scale cohort study, the Malmö Diet and Cancer (n = 29,298). Causality was evaluated with the Inverse Variance Weighted Method (IVW), and sensitivity analyses through MR-Egger. Results: Serum calcium level was found to be associated with DBP (IWV: beta = 11.9, SE = 4.2, p = 0.004). Surprisingly PTH didn’t show any association with the traits, while FGF23 was inversely associated with the SBP (IWV: beta = -5.0, SE = 2.0, P = 0.01) even if the association lost its significance at sensitivity analysis with MR-Egger. Conclusions: Our study shows a strong direct association between serum calcium level, described by its genetic component, with diastolic blood pressure. These results underline the importance of understanding the target genes that could alter calcium homeostasis and that could bring harmful implications later in life, moreover, it will be relevant for improving personalized intervention strategies. Despite not showing a strong association as the one shown by serum calcium level, the genetically predicted FGF23 level confirms its involvement in the regulation of blood pressure. Further an alyses deserve to be performed to clarify involved gene pathways.

Neotropical Monogenoidea 64. Cosmetocleithrum falsunilatum sp. n. (Monogenoidea, Dactylogyridae) parasite of the gills of Megalodoras uranoscopus (Siluriformes, Doradidae) from the Solimões river, near Iquitos, Peru.

Megalodoras uranoscopus (Eigenmann & Eigenmann) (Siluriformes, Doradidae) (the giant-talking catfishorthe giant-raphael catfish), from the Peruvian Amazon, hosts a new species of Cosmetocleithrum described herein as Cosmetocleithrum falsunilatum sp. n. The male copulatory organ of the new species closely resembles that of Unilatus spp. - with multiple tight loops and non-articulated accessory piece - which reveals its morphological uniqueness among members of Cosmetocleithrum. A phylogenetic analysis using 28S rDNA of available sequences suggests that Cosmetocleithrum is composed by two basal clades, one of them composed by sequences of the new species and C. trachydorasi.

A Systematic Approach to Reduce Wirebond defects caused by Tight Wire Loop Profile on Ball Grid Array Packages

Wirebond quality aspects on a semiconductor manufacturing is one of the key factors to be considered in having a robust product. Certain criteria are defined, met, and affects the output on the product. Other variables from downstream process are also taken in account to affect the response, specific die position or placement on die attach is one example. Without controlling this input factor, unwanted out of specification response will occur and may result to rejections on the next process. This paper will focus on how to address the wire tight loop on wire bond process by analyzing the problem through systematic approach using statistical tools improving the current performance of die placement on BGA products.

Touching Our Breathing through Shape-Change: Monster, Organic Other, or Twisted Mirror

We report on a soma design process, where we designed a novel shape-changing garment—the Soma Corset. The corset integrates sensing and actuation around the torso in tight interaction loops. The design process revealed how boundaries between the garment and the wearer can become blurred, leading to three flavours of cyborg relations. First, through the lens of the monster, we articulate how the wearer can adopt or reject the garment, resulting in either harmonious or disconcerting experiences of touch. Second, it can be experienced as an organic “other”-with its own agency-resulting in uncanny experiences of touch. Through mirroring the wearer’s breathing, the garment can also be experienced as a twisted version of one’s own body. We suggest that a gradual sensitisation of designers-through soma design and reflection on the emerging human-technology relations-may serve as a pathway for uncovering and articulating novel, machine-like, digital touch experiences.

Study on Single Jersey Knitted Fabrics Made from Cotton/ Polyester Core Spun Yarns. Part I: Thermal Comfort Properties

This study focused on the effect of core- sheath ratio, twist and loop length on the thermal comfort properties of single jersey knitted fabrics produced from 100% cotton, 80:20 and 60:40 cotton/polyester core spun yarns. Thermal properties like air permeability, water vapor permeability, thermal conductivity and thermal resistance properties were analyzed with low, medium and high twist and also with loose medium and tight structured fabrics. Box behnken, three level - three variable factorial design software has been used to study the interactive effect of core- sheath ratio, twist and loop length on the thermal comfort properties of single jersey knitted fabrics and response surface equations were derived and design variables were optimized. ANOVA test model reveals the statistical significance of variables on thermal properties with high F-value and low p-values. From this study it is observed that the decrease in cotton ratio decreases the fabric thickness, becomes lighter and more porous with higher thermal conductivity, air permeability, water vapour transmission rate and less thermal resistance. Increase in twist and tight loop structure makes thicker and less porous fabric with higher thermal resistance and lesser air permeability, water vapour transmission rate and thermal conductivity.

True umbilical cord knot and tight nuchal cord loops as a cause of fetal distress and emergent cesarean delivery: A Case report

True umbilical cord knot and tight nuchal cord loops as a cause of fetal distress and emergent cesarean delivery: A Case report

SyncUp

The beauty of synchronized dancing lies in the synchronization of body movements among multiple dancers. While dancers utilize camera recordings for their practice, standard video interfaces do not efficiently support their activities of identifying segments where they are not well synchronized. This thus fails to close a tight loop of an iterative practice process (i.e., capturing a practice, reviewing the video, and practicing again). We present SyncUp, a system that provides multiple interactive visualizations to support the practice of synchronized dancing and liberate users from manual inspection of recorded practice videos. By analyzing videos uploaded by users, SyncUp quantifies two aspects of synchronization in dancing: pose similarity among multiple dancers and temporal alignment of their movements. The system then highlights which body parts and which portions of the dance routine require further practice to achieve better synchronization. The results of our system evaluations show that our pose similarity estimation and temporal alignment predictions were correlated well with human ratings. Participants in our qualitative user evaluation expressed the benefits and its potential use of SyncUp, confirming that it would enable quick iterative practice.