60 research outputs found

    A simple thermodynamical witness showing universality of macroscopic entanglement

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    We show that if the ground state entanglement exceeds the total entropy of a given system, then this system is in an entangled state. This is a universal entanglement witness that applies to any physical system and yields a temperature below which we are certain to find some entanglement. Our witness is then applied to generic bosonic and fermionic many body systems to derive the corresponding "critical" temperatures that have a very broad validity.Comment: 3 pages, Torun conference, June 25-28, 200

    Fretting fatigue life prediction using the extended finite element method

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    In this work, fretting fatigue tests available in the literature are modeled using the extended finite element method (XFEM). The aim is to numerically evaluate the stress intensity factors (SIFs) for cracks of different lengths emanating at the end of the contact zone and to estimate the propagation life corresponding to each of the tests. This propagation life is combined with the initiation life calculated analytically using a multiaxial fatigue criterion (Fatemi-Socie), following a initiation-propagation approach for life estimation. The predicted lives are then compared with the reported experimental lives. It is shown that the consideration of the crack-contact interaction through the numerical models tends to improve the life estimation when compared with a fully analytical approach for the calculation of both initiation and propagation lives.Ministerio de Ciencia y Tecnología DPI2007-66995-C0301Ministerio de Ciencia y Tecnología DPI2007-66995-C03-02

    Viral and cellular telomerase RNAs possess host-specific anti-apoptotic functions

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    Human telomerase RNA (hTR) is overexpressed in many cancers and protects T cells from apoptosis in a telomerase-independent manner. The most prevalent cancer in the animal kingdom is caused by the highly oncogenic herpesvirus Marek’s disease virus (MDV). MDV encodes a viral telomerase RNA (vTR) that plays a crucial role in MDV-induced tumorigenesis and shares all four conserved functional domains with hTR. In this study, we assessed whether hTR drives tumor formation in this natural model of herpesvirus-induced tumorigenesis. Therefore, we replaced vTR with hTR in the genome of a highly oncogenic MDV. Furthermore, we investigated the anti-apoptotic activity of vTR, hTR, and their counterpart in the chicken [chicken telomerase RNA (cTR)]. hTR was efficiently expressed and did not alter replication of the recombinant virus. Despite its conserved structure, hTR did not complement the loss of vTR in virus-induced tumorigenesis. Strikingly, hTR did not inhibit apoptosis in chicken cells, but efficiently inhibited apoptosis in human cells. Inverse host restriction has been observed for vTR and cTR in human cells. Our data revealed that vTR, cTR, and hTR possess conserved but host-specific anti-apoptotic functions that likely contribute to MDV-induced tumorigenesis

    Influence of PST and PHF heating conditions on the swirl flow of Al+Mg+TiO2 ternary hybrid water-ethylene glycol based nanofluid with a rotating cone

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    Swirl flow heat exchangers are commonly used in industrial processes such as power generation, chemical processing, and refrigeration. They can be used for both heating and cooling applications and can be designed to handle a wide range of fluid flow rates and temperatures. This study investigated the influence of PST (prescribed surface temperature) and PHF (prescribed heat flux) heating conditions on the swirl flow of Al+Mg+TiO2 ternary hybrid water-ethylene glycol (50/50) based nanofluid with a heated rotating cone. The governing ordinary differential equations were derived from the partial differential equations using the proper similarity transformations. The problem was solved using the Shifted Legendre Collocation Method (SLCM), which is a powerful numerical method. The results showed that the PST heating conditions had a significant impact on the flow and heat transfer characteristics of the ternary hybrid nanofluid. Under PHF heating conditions, the swirl velocity distribution was leading to a noteworthy influence. The use of the Al+Mg+TiO2 ternary hybrid water-ethylene glycol based nanofluid resulted in a significant enhancement in the convective heat transfer coefficient. The SLCM method provided accurate and efficient numerical solutions for the problem, demonstrating its suitability for simulating complex fluid flow and heat transfer problems

    Molecular characterisation and antibiotic sensitivity profile of Pasteurella multocida isolated from poultry farms in Malaysia

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    Fowl cholera has caused significant economic losses in many poultry producing countries worldwide. In Malaysia, outbreaks of fowl cholera are frequently reported and encountered in different types of poultry productions. The objective of this study was to characterise 13 avian Pasteurella multocida, isolated from fowl cholera outbreaks in Central Peninsular Malaysia in the period between 2000 and 2018. The isolates were subjected to multiplex polymerase chain reaction (PCR) for capsular serotyping, disc diffusion method for antimicrobial susceptibility profiles, and molecular genotyping using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The capsular serotyping showed all 13 Pasteurella multocida isolates belonging to capsular serotype A. The antimicrobial susceptibility showed several multidrug resistance strains among the P. multocida isolates. All the isolates were resistant to erythromycin (100%), streptomycin (68%), tetracycline (37%), enrofloxacin (37%), florfenicol (23%), penicillin G (14%), gentamicin (14%), and amoxicillin (14%). The PFGE analysis clustered the isolates into three clones. Group A included isolates with a similarity of 87% from the year 2000, 2013, and 2018. Three sequence types were identified using MLST typing namely, ST129, ST231, and ST355. The ST355 was assigned for the first time in the Rural Industries Research and Development Corporation (RIRDC) database. Besides, ST129 has been reported in India, China, and Sri Lanka, which highlights the possibility of transmission between Asian countries. This study provides an insight into epidemiological information of Pasteurella multocida that causes fowl cholera outbreaks in the central region of Peninsular Malaysia

    Resonant laser-induced breakdown spectroscopy (RLIBS) analysis of traces through selective excitation of aluminum in aluminum alloys

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    We investigated laser-induced breakdown spectroscopy for the detection of traces of magnesium and silicon contained in aluminum alloys by using the same 5 ns optical parametric oscillator laser pulse to ablate the sample and excite selectively an atomic transition of vaporized aluminum (Al I 309.27 nm). The excitation energy of aluminum is then transferred to all components of the gas/plasma phase via particle collisions. The optical emission of the trace elements as a function of the laser wavelength exhibits a high peak when the laser is tuned exactly to the aluminum transition. The on-resonance signal-to-noise ratio of magnesium (Mg 285.21 nm) was maximized near the off-resonance threshold fluence for detection of the magnesium line ( 3c1.78 J cm-2). The detection threshold of the magnesium line decreases below 1.0 J cm-2 when the laser is on resonance for a sample of aluminum alloy containing 150 ppm of magnesium. Under optimal conditions, the limits of detection of magnesium and silicon in aluminum alloy were found to be 0.75 ppm and 80 ppm, respectively, compared to 39 ppm and 5000 ppm, respectively, when the laser was off resonance at the same fluence. The limits of detection obtained by using low fluences and low energy per pulse are similar to those obtained using conventional LIBS but with much higher fluences and higher energy per pulse. The main advantage of this technique is that it allows measuring simultaneously relatively low concentrations of several trace elements while minimizing the damage to the sample. \ua9 2013 The Royal Society of Chemistry.Peer reviewed: YesNRC publication: Ye
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