In Vitro Characterization of Scaffolds for Tissue Engineering - A Review

Scaffolds are artificial structures that replace the natural extracellular matrix (ECM). Scaffolds are capable of supporting three dimensional tissue formations. The natural ECM performs functions, like regulating intercellular communication along with providing support to the cells. A variety of fabricating methods are adopted for preparing scaffolds from a wide range of available biomaterials. The scaffolds thus produced can function as a successful scaffold only if they satisfy the necessary parameters. The suitability of any scaffold for tissue engineering application is tested by using a battery of tests that is a combination of mechanical and biological tests. This paper reviews the test methods adopted by researchers to test the suitability of scaffolds for tissue engineering applications

Classifying the Arithmetical Complexity of Teaching Models

This paper classifies the complexity of various teaching models by their position in the arithmetical hierarchy. In particular, we determine the arithmetical complexity of the index sets of the following classes: (1) the class of uniformly r.e. families with finite teaching dimension, and (2) the class of uniformly r.e. families with finite positive recursive teaching dimension witnessed by a uniformly r.e. teaching sequence. We also derive the arithmetical complexity of several other decision problems in teaching, such as the problem of deciding, given an effective coding $\{\mathcal L_0,\mathcal L_1,\mathcal L_2,\ldots\}$ of all uniformly r.e. families, any $e$ such that $\mathcal L_e = \{L^e_0,L^e_1,\ldots,\}$, any $i$ and $d$, whether or not the teaching dimension of $L^e_i$ with respect to $\mathcal L_e$ is upper bounded by $d$.Comment: 15 pages in International Conference on Algorithmic Learning Theory, 201

A genetic algorithm for cocyclic hadamard matrices

A genetic algorithm for finding cocyclic Hadamard matrices is described. Though we focus on the case of dihedral groups, the algorithm may be easily extended to cover any group. Some executions and examples are also included, with aid of Mathematica 4.0

Human exercise-induced circulating progenitor cell mobilization is nitric oxide-dependent and is blunted in South Asian men

This article is available open access through the publisher’s website. Copyright @ 2010 American Heart Foundation.Objective— Circulating progenitor cells (CPC) have emerged as potential mediators of vascular repair. In experimental models, CPC mobilization is critically dependent on nitric oxide (NO). South Asian ethnicity is associated with reduced CPC. We assessed CPC mobilization in response to exercise in Asian men and examined the role of NO in CPC mobilization per se. Methods and Results— In 15 healthy, white European men and 15 matched South Asian men, CPC mobilization was assessed during moderate-intensity exercise. Brachial artery flow-mediated vasodilatation was used to assess NO bioavailability. To determine the role of NO in CPC mobilization, identical exercise studies were performed during intravenous separate infusions of saline, the NO synthase inhibitor l-NMMA, and norepinephrine.  Flow-mediated vasodilatation (5.8%±0.4% vs 7.9%±0.5%; P=0.002) and CPC mobilization (CD34+/KDR+ 53.2% vs 85.4%; P=0.001; CD133+/CD34+/KDR+ 48.4% vs 73.9%; P=0.05; and CD34+/CD45− 49.3% vs 78.4; P=0.006) was blunted in the South Asian group. CPC mobilization correlated with flow-mediated vasodilatation and l-NMMA significantly reduced exercise-induced CPC mobilization (CD34+/KDR+ −3.3% vs 68.4%; CD133+/CD34+/KDR+ 0.7% vs 71.4%; and CD34+/CD45− −30.5% vs 77.8%; all P<0.001). Conclusion— In humans, NO is critical for CPC mobilization in response to exercise. Reduced NO bioavailability may contribute to imbalance between vascular damage and repair mechanisms in South Asian men.British Heart Foundatio

SiC power MOSFETs performance, robustness and technology maturity

Relatively recently, SiC power MOSFETs have transitioned from being a research exercise to becoming an industrial reality. The potential benefits that can be drawn from this technology in the electrical energy conversion domain have been amply discussed and partly demonstrated. Before their widespread use in the field, the transistors need to be thoroughly investigated and later validated for robustness and longer term stability and reliability. This paper proposes a review of commercial SiC power MOSFETs state-of-the-art characteristics and discusses trends and needs for further technology improvements, as well as device design and engineering advancements to meet the increasing demands of power electronics

NPM1 directs PIDDosome-dependent caspase-2 activation in the nucleolus

The PIDDosome (PIDD–RAIDD–caspase-2 complex) is considered to be the primary signaling platform for caspase-2 activation in response to genotoxic stress. Yet studies of PIDD-deficient mice show that caspase-2 activation can proceed in the absence of PIDD. Here we show that DNA damage induces the assembly of at least two distinct activation platforms for caspase-2: a cytoplasmic platform that is RAIDD dependent but PIDD independent, and a nucleolar platform that requires both PIDD and RAIDD. Furthermore, the nucleolar phosphoprotein nucleophosmin (NPM1) acts as a scaffold for PIDD and is essential for PIDDosome assembly in the nucleolus after DNA damage. Inhibition of NPM1 impairs caspase-2 processing, apoptosis, and caspase-2–dependent inhibition of cell growth, demonstrating that the NPM1-dependent nucleolar PIDDosome is a key initiator of the caspase-2 activation cascade. Thus we have identified the nucleolus as a novel site for caspase-2 activation and function

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

ЭФФЕКТИВНОСТЬ НОЧНОЙ ИНТУБАЦИИ ПРИ ОПЕРАЦИЯХ ПО ПОВОДУ РАКА ОРГАНОВ ПОЛОСТИ РТА – РЕТРОСПЕКТИВНОЕ ИССЛЕДОВАНИЕ

In the post-operative period of maxillofacial oncological operations, tracheostomy is the most commonly used method for securing the airway. These untoward complications made practitioners choose alternative modalities like submental intubation, but literature support on alternatives to tracheostomy for oral oncologic cases is limited. The aim of this observational study is to ascertain whether the use of overnight intubation is a safer and cost-effective practice and if it can be considered an alternative to tracheostomy.Material and methods. 30 patients, 23 males and 7 females in the age group of 34–80 years who underwent treatment for head and neck cancer with major intraoral resection and a unilateral or bilateral neck dissection were included in the study. The following variables were recorded: age, sex, site of tumour, type of neck dissection, use of mandibulotomy/ mandibulectomy, type of reconstruction, duration of stay in ICU, mean hospital stay and Mallampati classification. Postoperative complications, associated with the airway, if any, were recorded simultaneously.Results. None of the 30 patients required re-intubation nor did they develop any respiratory distress post extubation.Conclusion. The purpose of this study is to raise the conscience of every surgeon to cogitate his/her choice of procedure for his/her patients and advocate the use of overnight intubation, as it is a virtuous alternative to tracheostomy.В послеоперационном периоде у больных со злокачественными новообразованиями челюстно-лицевой области трахеостомия является самым распространенным методом, обеспечивающим проходимость воздушных путей. Осложнения трахеостомии побуждают врачей выбирать альтернативные методы, такие как субментальная интубация трахеи. Литературные данные об альтернативных трахеостомии методах при операциях по поводу опухолей органов полости рта ограничены.Цель исследования – выяснить, является ли использование ночной интубации более безопасной и рентабельной по цене, можно ли считать её альтернативой трахеостомии.Материал и методы. Исследование включало 30 больных раком органов головы и шеи (23 мужчины и 7 женщин) в возрасте 34–80 лет, которым была произведена внутриротовая резекция органов полости рта в большом объеме и односторонняя или двусторонняя шейная диссекция. Учитывались следующие параметры: возраст, пол, локализация опухоли, тип шейной диссекции, применение мандибулотомии/мандибулэктомии, тип реконструкции, продолжительность пребывания в реанимации, среднее время пребывания в больнице и классификация Маллампати. Также велась регистрация послеоперационных осложнений, связанных с обеспечением проходимости дыхательных путей.Результаты. Ни один из 30 пациентов не нуждался в повторной интубации, и у них не возникало каких-либо респираторных дистрессов после экстубации.Заключение. Цель этого исследования заключалось в том, чтобы каждый хирург мог обдумать и взвесить свой выбор процедуры для конкретного больного и выступить в поддержку ночной интубации как эффективной альтернативы трахеостомии