Acoustic emission analysis of the effect of a 2D wedge shaped blade on the compact bone cutting process

Surgeons may use a number of cutting instruments such as osteotomes and chisels to cut bone during an operative procedure. The initial loading of cortical bone during the cutting process results in the formation of microcracks in the vicinity of the cutting zone with main crack propagation to failure occuring with continued loading. When a material cracks, energy is emitted in the form of Acoustic Emission (AE) signals that spread in all directions, therefore, AE transducers can be used to monitor the occurrence and development of microcracking and crack propagation in cortical bone. In this research, number of AE signals (hits) and related parameters including amplitude, duration and absolute energy (abs-energy) were recorded during the indentation cutting process by a wedge blade on cortical bone specimens. The cutting force was also measured to correlate between load-displacement curves and the output from the AE sensor. The results from experiments show AE signals increase substantially during the loading just prior to fracture between 90% and 100% of maximum fracture load. Furthermore, an amplitude threshold value of 64dB (with approximate abs-energy of 1500 aJ) was established to saparate AE signals associated with microcracking (41 – 64dB) from fracture related signals (65 – 98dB). The results also demonstrated that the complete fracture event which had the highest duration value can be distinguished from other growing macrocracks which did not lead to catastrophic fracture. It was observed that the main crack initiation may be detected by capturing a high amplitude signal at a mean load value of 87% of maximum load and unsteady crack propagation may occur just prior to final fracture event at a mean load value of 96% of maximum load. The author concludes that the AE method is useful in understanding the crack initiation and fracture during the indentation cutting process.

Эмпирическая радиолокационная модель суперячейкового конвективного облака

სტატიაში გაანალიზებულია საქართველოს მთიანი რეგიონის სუპერუჯრედიან კონვექციურ ღრუბლებზე მრავალწლიანი რადიოლოკაციური დაკვირვებების მონაცემები.

Радиолокационные характеристики одноячейкового конвективного облака Кахетинского региона Грузии

შესწავლილია აღმოსავლეთ საქართველოს კახეთის რეგიონის ერთუჯრედიანი კონვექციური ღრუბლების რადიოექოს სტრუქტურა და განვითარების დინამიკა. გაანალიზებულია 352 ერთუჯრედიან ღრუბლებზე რადიოლოკაციური დაკვირვების მასალა და დადგენილია ასეთი კლასის ღრუბლების რადიოლოკაციური მახასიათებლების საშუალო და ექსტრემალური მნიშვნელობები.

Зависомость между максимальной радиолокационной отражаемостью одноячейковых конвективных облаков Кахетинского региона Грузии от средней интесивности атмосферных осадков

გაანალიზებულია საქართველოს კახეთის რეგიონის ერთუჯრედიანი კონვექციური ღრუბლების მაქსიმალური რადიოლოკაციური ამრეკვლადობის (Z) და ამ ღრუბლებიდან მოსული ნალექების საშუალო ინტენსივობის (I) შესახებ მონაცეები. სტატისტიკური ამონაკრების მოცულობამ შეადგინა 460 შემთხვევა.

Изменение во времени нормированных значений радиолокационных параметров конвективных облаков под влиянием искусственного воздействия

სტატიაში გამოკვლეულია ზემოქმედებაქმნილი და არაზემოქმედებაქმნილი კონვექციური ღრუბლების ზოგიერთი რადიოლოკაციური პარამეტრის ნორმირებული მნიშვნელობების დროში ცვალებადობა.

Mechanische Charakterisierung von Konstruktionskeramik im oberflächennahen Bereich

Engineering ceramics, indentation methods, crack-resistance, Rayleigh waves, acoustic microscopy, machining parameters, green ceramic bodies, ultrasonic contact impedance, acoustic impedance, residual stress

Fingermorphologie in der Elektrodeposition, ein komplexes Grenzflächenphänomen

Electrodeposition, morphology, density-driven convection, fingering, dispersion relation

Einfluss der Mikrokonvektion auf Selektivität und Stofftransport während der Verdunstung binärer Flüssigkeiten aus porösen Schichten

Interfacial convection, enhancement of mass transfer, packed beds, evaporation, selectivity

Mechanismus und Beeinflussung von Trockenausblühungen aus Kalziumsulfat bei der Konvektionstrocknung von Ziegelrohlingen

Drying, dryer scumming, brick, calcium sulphate, crystallisation, diffusion, convection

Proteomic and Metabolomic Analyses of Mitochondrial Complex I-deficient Mouse Model Generated by Spontaneous B2 Short Interspersed Nuclear Element (SINE) Insertion into NADH Dehydrogenase (Ubiquinone) Fe-S Protein 4 (Ndufs4) Gene.

Eukaryotic cells generate energy in the form of ATP, through a network of mitochondrial complexes and electron carriers known as the oxidative phosphorylation system. In mammals, mitochondrial complex I (CI) is the largest component of this system, comprising 45 different subunits encoded by mitochondrial and nuclear DNA. Humans diagnosed with mutations in the gene NDUFS4, encoding a nuclear DNA-encoded subunit of CI (NADH dehydrogenase ubiquinone Fe-S protein 4), typically suffer from Leigh syndrome, a neurodegenerative disease with onset in infancy or early childhood. Mitochondria from NDUFS4 patients usually lack detectable NDUFS4 protein and show a CI stability/assembly defect. Here, we describe a recessive mouse phenotype caused by the insertion of a transposable element into Ndufs4, identified by a novel combined linkage and expression analysis. Designated Ndufs4(fky), the mutation leads to aberrant transcript splicing and absence of NDUFS4 protein in all tissues tested of homozygous mice. Physical and behavioral symptoms displayed by Ndufs4(fky/fky) mice include temporary fur loss, growth retardation, unsteady gait, and abnormal body posture when suspended by the tail. Analysis of CI in Ndufs4(fky/fky) mice using blue native PAGE revealed the presence of a faster migrating crippled complex. This crippled CI was shown to lack subunits of the "N assembly module", which contains the NADH binding site, but contained two assembly factors not present in intact CI. Metabolomic analysis of the blood by tandem mass spectrometry showed increased hydroxyacylcarnitine species, implying that the CI defect leads to an imbalanced NADH/NAD(+) ratio that inhibits mitochondrial fatty acid β-oxidation.

Low-Dose Vascular Photodynamic Therapy Decreases Tumor Interstitial Fluid Pressure, which Promotes Liposomal Doxorubicin Distribution in a Murine Sarcoma Metastasis Model.

INTRODUCTION: Solid tumors are known to have an abnormal vasculature that limits the distribution of chemotherapy. We have recently shown that tumor vessel modulation by low-dose photodynamic therapy (L-PDT) could improve the uptake of macromolecular chemotherapeutic agents such as liposomal doxorubicin (Liporubicin) administered subsequently. However, how this occurs is unknown. Convection, the main mechanism for drug transport between the intravascular and extravascular spaces, is mostly related to interstitial fluid pressure (IFP) and tumor blood flow (TBF). Here, we determined the changes of tumor and surrounding lung IFP and TBF before, during, and after vascular L-PDT. We also evaluated the effect of these changes on the distribution of Liporubicin administered intravenously (IV) in a lung sarcoma metastasis model. MATERIALS AND METHODS: A syngeneic methylcholanthrene-induced sarcoma cell line was implanted subpleurally in the lung of Fischer rats. Tumor/surrounding lung IFP and TBF changes induced by L-PDT were determined using the wick-in-needle technique and laser Doppler flowmetry, respectively. The spatial distribution of Liporubicin in tumor and lung tissues following IV drug administration was then assessed in L-PDT-pretreated animals and controls (no L-PDT) by epifluorescence microscopy. RESULTS: L-PDT significantly decreased tumor but not lung IFP compared to controls (no L-PDT) without affecting TBF. These conditions were associated with a significant improvement in Liporubicin distribution in tumor tissues compared to controls (P < .05). DISCUSSION: L-PDT specifically enhanced convection in blood vessels of tumor but not of normal lung tissue, which was associated with a significant improvement of Liporubicin distribution in tumors compared to controls.

Stable isotope composition of smectite in suevites at the Ries crater, Germany: Implications for hydrous alteration of impactites

The 24-km diameter Ries crater, Germany, exhibits well-preserved crater filling and surficial melt-rich breccia deposits that are believed to have been altered by post-impact hydrothermal fluids. The alteration mineralogy of the crater filling breccias is characterized by clay (smectite, chlorite) and a zeolite assemblage, and secondary clay phases (smectite, minor halloysite) in surficial melt-bearing breccia deposits. Using stable isotope analysis of secondary smectitic clay fractions, evidence of significant hydrous alteration of impactites at large water/rock ratios was found. The estimated fluid temperatures, using data derived by delta(18)O and delta D fractionation, suggest smectite precipitation in surficial breccias in equilibrium with meteoric fluids at temperatures 16 +/- 5 degrees C in agreement with the long-term variation of modern precipitation in the area. The stable isotope composition of smectite in crater-fill breccia, however, suggests a trend of monotonously increasing temperatures from 43 to 112 degrees C. with increasing depth through the breccia sequence. This demonstrates a different origin of alteration and temperature distribution for the surficial and crater filling melt-bearing impact breccias in the Ries crater. Our results suggest that the inverted structure of hydrothermal systems observed in some terrestrial impact craters, including the Ries crater, could indicate the initial configuration of a thermal anomaly in the crater filling sequence, but which is replaced with a normal hydrothermal convection in crater proper, during the course of post-impact cooling. (C) 2010 Elsevier B.V. All rights reserved.

Force-induced globule-coil transition in laminin binding protein and its role for viral-cell membrane fusion.

The specific interactions of the pairs laminin binding protein (LBP)-purified tick-borne encephalitis viral surface protein E and certain recombinant fragments of this protein, as well as West Nile viral surface protein E and certain recombinant fragments of that protein, are studied by combined methods of single-molecule dynamic force spectroscopy (SMDFS), enzyme immunoassay and optical surface waves-based biosensor measurements. The experiments were performed at neutral pH (7.4) and acid pH (5.3) conditions. The data obtained confirm the role of LBP as a cell receptor for two typical viral species of the Flavivirus genus. A comparison of these data with similar data obtained for another cell receptor of this family, namely human αVβ3 integrin, reveals that both these receptors are very important. Studying the specific interaction between the cell receptors in question and specially prepared monoclonal antibodies against them, we could show that both interaction sites involved in the process of virus-cell interaction remain intact at pH 5.3. At the same time, for these acid conditions characteristic for an endosome during flavivirus-cell membrane fusion, SMDFS data reveal the existence of a force-induced (effective already for forces as small as 30-70 pN) sharp globule-coil transition for LBP and LBP-fragments of protein E complexes. We argue that this conformational transformation, being an analog of abrupt first-order phase transition and having similarity with the famous Rayleigh hydrodynamic instability, might be indispensable for the flavivirus-cell membrane fusion process. Copyright © 2014 John Wiley & Sons, Ltd.

International Olympic Committee consensus statement on thermoregulatory and altitude challenges for high-level athletes

Challenging environmental conditions, including heat and humidity, cold, and altitude, pose particular risks to the health of Olympic and other high-level athletes. As a further commitment to athlete safety, the International Olympic Committee (IOC) Medical Commission convened a panel of experts to review the scientific evidence base, reach consensus, and underscore practical safety guidelines and new research priorities regarding the unique environmental challenges Olympic and other international-level athletes face. For non-aquatic events, external thermal load is dependent on ambient temperature, humidity, wind speed and solar radiation, while clothing and protective gear can measurably increase thermal strain and prompt premature fatigue. In swimmers, body heat loss is the direct result of convection at a rate that is proportional to the effective water velocity around the swimmer and the temperature difference between the skin and the water. Other cold exposure and conditions, such as during Alpine skiing, biathlon and other sliding sports, facilitate body heat transfer to the environment, potentially leading to hypothermia and/or frostbite; although metabolic heat production during these activities usually increases well above the rate of body heat loss, and protective clothing and limited exposure time in certain events reduces these clinical risks as well. Most athletic events are held at altitudes that pose little to no health risks; and training exposures are typically brief and well-tolerated. While these and other environment-related threats to performance and safety can be lessened or averted by implementing a variety of individual and event preventative measures, more research and evidence-based guidelines and recommendations are needed. In the mean time, the IOC Medical Commission and International Sport Federations have implemented new guidelines and taken additional steps to mitigate risk even further.

Desequilibri 234Th/238U per a l'estudi del cicle de partícules al Mediterrani nord-occidental

El desequilibri 238U/234Th s’utilitza per traçar el cicle de les partícules a la part més superficial dels oceans. Això és possible degut a les diferències entre els seus períodes de semidesintegració (T1/2 (234Th)=24,1 d; T1/2 (238U)=4,5 10 9 anys) i a les seves característiques biogeoquímiques: el Th presenta una gran afinitat per les partícules mentre que l’U és conservatiu en aigua de mar. En absència de partícules s’esperaria tenir equilibri secular entre ambdós radionúclids, però com que l’oceà no està lliure de partícules, el 234Th és exportat des de les capes més superficials produint-se un dèficit respecte el seu pare, l’238U. El període de semidesintegració del 234Th és molt adequat per traçar processos d’escales temporals de dies a setmanes, del mateix ordre que el desenvolupament de la floració del fitoplàncton i a la posterior exportació de partícules. En aquest treball es presenten dades obtingudes durant dues campanyes oceanogràfiques realitzades en el marc del Projecte FAMOSO (2009) en el Mediterrani nordoccidental, abans i després de la floració de fitoplàncton de primavera a la zona. Una de les peculiaritats d’aquesta regió és el procés de convecció profunda d’hivern, el qual suposa un important mecanisme de fertilització. A partir dels fluxos de 234Th obtinguts a la columna d’aigua es poden establir les pautes temporals que ha seguit el fitoplàncton en les setmanes prèvies al mostreig. Aquesta informació es compara amb els fluxos obtinguts utilitzant trampes de sediment a la deriva instal·lades durant ambdues campanyes.