Original Effective, Safe Technique of Obtaining Platelet Rich Plasma by Centrifugation of the Blood Plasma in Modified Syringe Containers

The aim: to develop, substantiate an effective and safe technology for producing PRP (platelet rich plasma). To quantify the substrate based on the recommended centrifugation protocols.Materials and methods: the effectiveness of the original harvesting protocol was evaluated by quantifying the number of platelets. The proposed technique is formed basing on the basic principles of double centrifugation of whole blood in test tubes with anticoagulant, separation with the release of a plasma layer with a high content of platelets.The centrifuging mode for quantifying the effectiveness of the substrate was selected according to recommendations based on a study confirming maximum efficiency (160g×10min + 250g×15min).For quantitative evaluation, blood was collected from 10 healthy volunteers (7 men, 3 women) with an average age of 26.0±2.6, and centrifuged in standard mode. Quantitative evaluation of platelets of whole blood and the obtained PRP substrate was carried out with a semi-automatic analyzer.Results: the proposed technique is based on the use as a container for centrifuging a syringe with a LuerLock design, which is hermetically sealed with a congruent plug, adapted by the external size of the centrifuge rotor bowl. Phase selection after centrifugation was performed by aspiration of the syringe contents after centrifugation is performed through a three-way valve. The substrate was obtained by repeated centrifugation of the contents, which allows obtaining a variable volume and platelet concentration in PRP. The amount of platelets (PLT) of whole blood is 227.0±57.0 thousand per ml. PLT PRP 945.0±279.0 thousand per ml.Conclusions: the proposed method of separation of whole blood with the release of the platelet rich plasma demonstrates high efficiency, which corresponds to the level of increasing the number of platelets in reducing the volume at the level of the best ready-made solutions.The equipment is economical and does not require highly specialized equipment and consumables. The proposed technique provides a wide choice to the performer in the received volume of the substrate

Ein Wettrüsten in Südostasien? Veränderte Rüstungsdynamiken, regionale Sicherheit und die Rolle europäischer Waffenexporte

Südostasien rüstet massiv auf. In der letzten Dekade stiegen die Militärausgaben in den Staaten der Region durchschnittlich um 57 Prozent. Als Auslöser für die sprunghaft erhöhten Waffenkäufe wird häufig das zunehmend offensivere Auftreten Chinas im Pazifik benannt. Die Studie zeigt jedoch, dass neben dem „China-Faktor“ auch andere außen- und innenpolitische Faktoren ausschlaggebend waren für den Anstieg der Militärausgaben: anhaltende territoriale Konflikte, militante Aufstands­bewegungen im Innern und der starke politische Einfluss des Militärs. Auch wenn kein direkter Zusammenhang nachgewiesen werden kann zwischen einem Wett­rüsten und einem Anstieg der Wahrscheinlichkeit, dass es zu einem Ausbruch kriegeri­scher Gewalt kommt, so bedeutet dies nicht, dass die Region Südostasien durch die derzeitige Aufrüstung an Stabilität gewönne. Denn mit der quantitativen und qualitativen Erhöhung der militärischen Kapazitäten haben sich Bedrohungsperzep­tionen verstärkt und ist das Misstrauen in der Region größer geworden. Dies zeigt sich an den vermehrten Zusammenstößen zwischen immer höher gerüsteten Sicher­heitskräften. Vor diesem Hintergrund sind Deutschland wie auch viele seiner europäischen Nachbarn gut beraten, die eigene Rolle als zentraler Waffenlieferant Südostasiens viel stärker als bisher strategisch zu durchdenken und kritisch zu hinterfragen. Bislang betrachten Deutschland und die EU das Rüstungsgeschäft mit südostasiatischen Abnehmern primär aus wirtschaftlicher Perspektive. Sie sollten jedoch einen politischen und strategischen Diskurs über die Auswirkungen ihrer Waffenexporte führen. (Autorenreferat

Nonparametric Instrumental Variable Estimation Under Monotonicity

The ill‐posedness of the nonparametric instrumental variable (NPIV) model leads to estimators that may suffer from poor statistical performance. In this paper, we explore the possibility of imposing shape restrictions to improve the performance of the NPIV estimators. We assume that the function to be estimated is monotone and consider a sieve estimator that enforces this monotonicity constraint. We define a constrained measure of ill‐posedness that is relevant for the constrained estimator and show that, under a monotone IV assumption and certain other mild regularity conditions, this measure is bounded uniformly over the dimension of the sieve space. This finding is in stark contrast to the well‐known result that the unconstrained sieve measure of ill‐posedness that is relevant for the unconstrained estimator grows to infinity with the dimension of the sieve space. Based on this result, we derive a novel non‐asymptotic error bound for the constrained estimator. The bound gives a set of data‐generating processes for which the monotonicity constraint has a particularly strong regularization effect and considerably improves the performance of the estimator. The form of the bound implies that the regularization effect can be strong even in large samples and even if the function to be estimated is steep, particularly so if the NPIV model is severely ill‐posed. Our simulation study confirms these findings and reveals the potential for large performance gains from imposing the monotonicity constraint

Evaluation of centrifuging regimes for the purpose of optimizing the platelet rich plasma harvesting protocol

Aim: Based on the classical principles, to determine the optimal conditions for centrifugation, PRP harvesing (platelet-rich plasma). To conduct a quantitative assessment of the substrate obtained under different conditions of centrifugation. Based on the basic principles of obtaining platelet-rich plasma (PRP) by centrifuging in containers with an anticoagulant followed by phase separation to obtain the fnal substrate, the effciency of the technique under the conditions of single and double centrifugation as well as under different conditions of acceleration and centrifugation was evaluated. Blood for follow-up was collected from 20 healthy volunteers (11 men, 9 women) average 25.3±4.1 in syringes of LuerLock design with ACD-A anticoagulant solution, and centrifuged. Centrifugation was carried out under controlled conditions using a centrifuge with rotating bowls of the rotor. Centrifugation was performed at an acceleration of 100–400 g in time intervals up to 20 minutes. Activation of the substrate was performed with calcium chloride solution. Quantitative evaluation of platelets of whole blood and the fnal substrate of PRP was carried out with a semi-automatic analyzer. The obtained results demonstrate the maximum level of harvesting effciency when performing double centrifugation in the 150g × 15 min+250g × 10 min mode. Subject to this centrifugation protocol, it is possible to obtain a substrate that complies with the standardized requirements for PRP. The maximum level of an increase in the number of platelets in the substrate in comparison with whole blood is determined at the level of ×4.36 with concentration (volume reduction) ×5 in comparison with the volume of whole blood. This study demonstrated the advantage of double centrifuging modes over single modes. According to the results of the study, it was possible to determine the conditions for an optimal double-centrifugation mode (acceleration and duration), which allows us to achieve the most effcient concentration of the substrate

Anatomically Constrained Video-CT Registration via the V-IMLOP Algorithm

Functional endoscopic sinus surgery (FESS) is a surgical procedure used to treat acute cases of sinusitis and other sinus diseases. FESS is fast becoming the preferred choice of treatment due to its minimally invasive nature. However, due to the limited field of view of the endoscope, surgeons rely on navigation systems to guide them within the nasal cavity. State of the art navigation systems report registration accuracy of over 1mm, which is large compared to the size of the nasal airways. We present an anatomically constrained video-CT registration algorithm that incorporates multiple video features. Our algorithm is robust in the presence of outliers. We also test our algorithm on simulated and in-vivo data, and test its accuracy against degrading initializations.Comment: 8 pages, 4 figures, MICCA

New methods for econometric inference

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 201-208).Monotonicity is a key qualitative prediction of a wide array of economic models derived via robust comparative statics. It is therefore important to design effective and practical econometric methods for testing this prediction in empirical analysis. Chapter 1 develops a general nonparametric framework for testing monotonicity of a regression function. Using this framework, a broad class of new tests is introduced, which gives an empirical researcher a lot of flexibility to incorporate ex ante information she might have. Chapter 1 also develops new methods for simulating critical values, which are based on the combination of a bootstrap procedure and new selection algorithms. These methods yield tests that have correct asymptotic size and are asymptotically nonconservative. It is also shown how to obtain an adaptive rate optimal test that has the best attainable rate of uniform consistency against models whose regression function has Lipschitz-continuous first-order derivatives and that automatically adapts to the unknown smoothness of the regression function. Simulations show that the power of the new tests in many cases significantly exceeds that of some prior tests, e.g. that of Ghosal, Sen, and Van der Vaart (2000). An application of the developed procedures to the dataset of Ellison and Ellison (2011) shows that there is some evidence of strategic entry deterrence in pharmaceutical industry where incumbents may use strategic investment to prevent generic entries when their patents expire. Many economic models yield conditional moment inequalities that can be used for inference on parameters of these models. In chapter 2, I construct a new test of conditional moment inequalities based on studentized kernel estimates of moment functions. The test automatically adapts to the unknown smoothness of the moment functions, has uniformly correct asymptotic size, and is rate optimal against certain classes of alternatives. Some existing tests have nontrivial power against n-1/2 -local alternatives of a certain type whereas my method only allows for nontrivial testing against (n/ log n)-1/2-local alternatives of this type. There exist, however, large classes of sequences of well-behaved alternatives against which the test developed in this paper is consistent and those tests are not. In chapter 3 (coauthored with Victor Chernozhukov and Kengo Kato), we derive a central limit theorem for the maximum of a sum of high dimensional random vectors. Specifically, we establish conditions under which the distribution of the maximum is approximated by that of the maximum of a sum of the Gaussian random vectors with the same covariance matrices as the original vectors. The key innovation of this result is that it applies even when the dimension of random vectors (p) is large compared to the sample size (n); in fact, p can be much larger than n. We also show that the distribution of the maximum of a sum of the random vectors with unknown covariance matrices can be consistently estimated by the distribution of the maximum of a sum of the conditional Gaussian random vectors obtained by multiplying the original vectors with i.i.d. Gaussian multipliers. This is the multiplier bootstrap procedure. Here too, p can be large or even much larger than n. These distributional approximations, either Gaussian or conditional Gaussian, yield a high-quality approximation to the distribution of the original maximum, often with approximation error decreasing polynomially in the sample size, and hence are of interest in many applications. We demonstrate how our central limit theorem and the multiplier bootstrap can be used for high dimensional estimation, multiple hypothesis testing, and adaptive specification testing. All these results contain non-asymptotic bounds on approximation errors.by Denis Chetverikov.Ph.D

Циторедуктивна хірургія при хіміорезистентній лейоміосаркомі матки

Циторедуктивна хірургія при хіміорезистентній лейоміосаркомі матк