Disentangling Scaling Properties in Anisotropic Fracture

Structure functions of rough fracture surfaces in isotropic materials exhibit complicated scaling properties due to the broken isotropy in the fracture plane generated by a preferred propagation direction. Decomposing the structure functions into the even order irreducible representations of the SO(2) symmetry group (indexed by $m=0,2,4...$) results in a lucid and quickly convergent description. The scaling exponent of the isotropic sector ($m=0$) dominates at small length scales. One can reconstruct the anisotropic structure functions using only the isotropic and the first non vanishing anisotropic sector ($m=2$) (or at most the next one ($m=4$)). The scaling exponent of the isotropic sector should be observed in a proposed, yet unperformed, experiment.Comment: 5 pages, 8 figure

Statistical Physics of Fracture Surfaces Morphology

Experiments on fracture surface morphologies offer increasing amounts of data that can be analyzed using methods of statistical physics. One finds scaling exponents associated with correlation and structure functions, indicating a rich phenomenology of anomalous scaling. We argue that traditional models of fracture fail to reproduce this rich phenomenology and new ideas and concepts are called for. We present some recent models that introduce the effects of deviations from homogeneous linear elasticity theory on the morphology of fracture surfaces, succeeding to reproduce the multiscaling phenomenology at least in 1+1 dimensions. For surfaces in 2+1 dimensions we introduce novel methods of analysis based on projecting the data on the irreducible representations of the SO(2) symmetry group. It appears that this approach organizes effectively the rich scaling properties. We end up with the proposition of new experiments in which the rotational symmetry is not broken, such that the scaling properties should be particularly simple.Comment: A review paper submitted to J. Stat. Phy

A Scalable Heterogeneous Solution for Massive Data Collection and Database Loading

Abstract. Massive collection of data at high rates is critical for many industries. Typically, a massive stream of records is gathered from the business information network at a very high rate. Because of the complexity of the collection process, the classical database solution falls short. The high volume and rate of records involved requires a heterogeneous pipeline comprised of two major parts: a system that carries out massive collection and then uploads the information to a database, and a subsequent data analysis and management system consisting of an Extract Transform and Load component. We developed a massive collection and loading system, based on a highly scalable heterogeneous architecture solution. The solution has been applied successfully for Telco revenue assurance, and can be applied to other industrial areas. The solution was successful in scaling up a Telco client system to handle streams of records ten times larger than was previously possible.

Reduced culture temperature attenuates oxidative stress and inflammatory response facilitating expansion and differentiation of adipose-derived stem cells

BackgroundAdipose-derived stem cell (ASC) expansion under atmospheric oxygen levels (21%) was previously shown to cause increased reactive oxygen species (ROS) accumulation and genetic instability compared to cells cultured under physiological oxygen levels (2–8%). However, since culture under physiological oxygen levels is costly and complicated, a simpler method to reduce ROS accumulation is desirable. The current study aimed to determine whether lower culture temperature can reduce ROS production in ASCs without impairing their culture expansion.MethodsProliferation, differentiation, ROS accumulation, and gene expression were compared between ASC cultures at 35 °C and 37 °C. ASCs isolated either from rat fat depots or from human lipoaspirates were examined in the study.ResultsRat visceral ASCs (vASCs) cultured at 35 °C demonstrated reduced ROS production and apoptosis and enhanced expansion and adipogenic differentiation compared to vASCs cultured at 37 °C. Similarly, the culture of human ASCs (hASCs) at 35 °C led to reduced ROS accumulation and apoptosis, with no effect on the proliferation rate, compared to hASCs cultured at 37 °C. Comparison of gene expression profiles of 35 °C versus 37 °C vASCs uncovered the development of a pro-inflammatory phenotype in 37 °C vASCs in correlation with culture temperature and ROS overproduction. This correlation was reaffirmed in both hASCs and subcutaneous rat ASCs.ConclusionsThis is the first evidence of the effect of culture temperature on ASC growth and differentiation properties. Reduced temperatures may result in superior ASC cultures with enhanced expansion capacities in vitro and effectiveness in vivo

Targeted Delivery of Adipose Derived Stem Cells into a Transplant by Direct Intra-Arterial Administration

Objective: Mesenchymal Stem Cells (MSCs) are adult multipotent cells that possess regenerative and immunosuppressant properties. Homing of MSCs to target organs remains a major challenge as intravenous delivery results in intravascular entrapment of most MSCs in vascularized organs. Intra-Arterial (IA) administration of MSCs to arteries feeding a specific organ improved the delivery of cells to these organs but often resulted in vessels obstruction. To improve targeting of MSCs into a transplant we designed a novel method for IA delivery of MSCs during the transplantation procedure. This study was aimed at evaluating the safety and efficacy of this method.Methods: A syngeneic groin free flap between Lewis rats was performed in all experiment groups. Treatment groups included 3 groups (n ≥ 7) in which 1 × 106, 0.5 × 106 or 0.05 × 106 adipose derived MSCs (ASCs) were administered via a femoral artery branch prior to the final reperfusion of the flap. In vivo real time fluorescence imaging and intravital microscopy were used to define ASCs IA movement after transplantation.Results: High concentrations of ASCs per injection resulted in poor flap survival rates (14.3%) due to flap necrosis. At 0.05 × 106 ASCs, increased long-term flap viability rates (85%) were observed. Whole-body imaging of fluorescently labeled ASCs demonstrated significant targeting of cells into the flap even at such a low cell quantity. ASCs were detected in proximity to small blood vessels within the viable flap.Conclusions: Local IA administration of ASCs into a vascularized transplant/flap is feasible and allows high local cell concentrations with minimal cell dosing

NOX1-induced accumulation of reactive oxygen species in abdominal fat-derived mesenchymal stromal cells impinges on long-term proliferation

Mesenchymal stromal cells (MSCs) are multipotent and can be derived from different adult tissues including fat. Our repeated attempts to produce long-term proliferative cultures of rat abdominal adipose stem cells (aASCs) under normal oxygen concentration (21%) were unsuccessful. We set to examine the events controlling this cytostasis of aASCs and found that it resulted from overproduction of reactive oxygen species (ROS) that led to apoptosis. ROS overproduction in aASCs was accompanied by increased expression of NOX1 but not of NOX2 or NOX4. NOX family members are an important source of intracellular ROS pointing to NOX1 involvement in ROS accumulation. This was verified when aASCs that were grown under 3% oxygen conditions expanded long term, displaying reduced NOX1 expression and decreased ROS accumulation. NOX1 involvement in aASC cytostasis was reaffirmed when cells that were expanded under normoxic conditions in the presence of a specific NOX1 inhibitor, ML171, demonstrated reduced ROS accumulation, reduced apoptosis and long-term expansion. aASC expansion arrest was accompanied also by a weak fat differentiation and migratory potential, which was enhanced by NOX1 inhibition. This suggests an inhibitory role for NOX1-induced ROS overproduction on aASCs, their fat differentiation and migratory potential. In contrast to aASCs, similar cells produced from subcutaneous fat were easily expanded in normoxic cultures, exhibiting low ROS concentrations, a low number of apoptotic cells and improved fat differentiation and migration. Taken together, our results show, for the first time, that NOX1-induced ROS accumulation halts ASC expansion and reduces their differentiation and migratory potential under normoxic conditions. Importantly, this phenotype comprises a tissue-specific signature as it was evident in aASCs but not in subcutaneous ASCs. NOX-induced ROS accumulation and cytokine production by fat are part of the metabolic syndrome. The similarity of this phenomenon to aASC phenotype may indicate that they arise from similar molecular mechanisms

Rapid implementation of teledentistry during the Covid-19 lockdown

Introduction: The current corona virus disease 2019 (COVID-19) outbreak set new challenges to nearly all health plans and large health organizations worldwide, including movement restrictions, strict limitations in healthcare services, especially in the dental profession, and patient fears regarding potential infection. Telehealth can serve as an effective platform for remote connection between dental healthcare providers and patients, and can help reduce the risk of infection when social distancing is required. Objective: The current study aimed to evaluate the quality of treatment provided via teledentistry, as perceived by patients using the service, as well as their willingness to use online distant medical consultation in the future. Methods: Since March 2020, a new online service was implemented in the Oral Medicine Unit and Oral and Maxillofacial Surgery Department in the Galilee Medical Center, to expand the range of services beyond merely emergency treatments. Results: The current study examined the quality of teledentistry services as perceived by 89 patients participating in at least one teleconsultation, and their acceptance of remote healthcare. Satisfaction rates were high in patients who received both full and partial solution to their chief complaint. Moreover, acceptance of the teledentistry platform was high, even in the older age groups. Conclusions: We propose to implement teledentistry services in current and future pandemics, as well as during routine times, to strengthen our health care system with digital technologies

Validating bifidobacterial species and subspecies identity in commercial probiotic products.

BackgroundThe ingestion of probiotics to attempt to improve health is increasingly common; however, quality control of some commercial products can be limited. Clinical practice is shifting toward the routine use of probiotics to aid in prevention of necrotizing enterocolitis in premature infants, and probiotic administration to term infants is increasingly common to treat colic and/or prevent atopic disease. Since bifidobacteria dominate the feces of healthy breast-fed infants, they are often included in infant-targeted probiotics.MethodsWe evaluated 16 probiotic products to determine how well their label claims describe the species of detectable bifidobacteria in the product. Recently developed DNA-based methods were used as a primary means of identification, and were confirmed using culture-based techniques.ResultsWe found that the contents of many bifidobacterial probiotic products differ from the ingredient list, sometimes at a subspecies level. Only 1 of the 16 probiotics perfectly matched its bifidobacterial label claims in all samples tested, and both pill-to-pill and lot-to-lot variation were observed.ConclusionGiven the known differences between various bifidobacterial species and subspecies in metabolic capacity and colonization abilities, the prevalence of misidentified bifidobacteria in these products is cause for concern for those involved in clinical trials and consumers of probiotic products