2,028 research outputs found

    ESD Behavior of RF Switches and Importance of System Efficient ESD Design

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    RF Switches Are Typically Used in the RF Front-End of Portable Devices Such as Antenna or Matching Tuners to Improve the RF Link Performance. They Are Usually the First Active Devices after the Antenna and Are Vulnerable to Primary or Secondary ESD Discharges to the Antennas. This Paper Investigates the ESD Behavior of One of the High Frequency Switches Used in the RF-Front-End of Portable Devices and Expresses the Importance of the ESD Pulse that Passes through the Switch and Reaches the Next Stage in the RF Path, Possibly Damaging the Next Stage

    A review of relationship between presenting symptoms and tumour location in colorectal carcinoma in tertiary centre hospital

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    Colorectal cancer is ranked as the most common cancer for men and the second most common cancer for women according to the Malaysian National Cancer Registry Report (MNCR) 2007-2011. However, delay in the diagnosis of colorectal cancer is still common partly attributable due to late presentation and incorrect diagnosis by the general practitioners. The aim of this study is to determine the relationship between presenting symptoms of colorectal cancer to the location of the tumour in order to prevent delay in diagnosis of colorectal cancer. Between 1996 until 2009, a total of 212 patient data from Hospital Universiti Sains Malaysia were retrospectively analyzed. The demographic and surgical data were obtained. We studied the relationship of the presenting symptoms of colorectal cancer to the location of the tumour. The age of candidate included in this study range from 16 to 93 years old with mean age was 56 and male predominance. In this study, there is a strong relationship between presenting symptoms and the location of the colorectal cancer but no significant relationship between age and sex to the anatomical location of the tumour. The study showed the presenting symptoms of rectal bleeding, change in bowel habit and tenesmus were significantly associated with rectal tumor, intestinal obstruction with left sided tumors and anemia and abdominal mass with right sided tumors (p-value <0.05). However abdominal pain does not follow this role as it is mostly associated with other presenting symptoms and it has no significant relation to the anatomical location of the tumor

    Fever-Induced QTc Prolongation and Ventricular Fibrillation in a Healthy Young Man

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    Long QT syndrome is associated with lethal tachyarrhythmia that can lead to syncope, seizure, and sudden death. Congenital long QT syndrome is a genetic disorder, characterized by delayed cardiac repolarization and prolongation of the QT interval on the electrocardiogram (ECG). Type 2 congenital long QT is linked to mutations in the human ether a go-go-related gene (HERG). There are environmental triggers of adverse cardiac events such as emotional and acoustic stimuli, but fever can also be a potential trigger of life-threatening arrhythmias in long QT syndrome type 2 patients. Herein, we report a healthy young man who experienced fever-induced polymorphic ventricular tachycardia and QT interval prolongation

    Comparison of the force exerted by hippocampal and DRG growth cones

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    Mechanical properties such as force generation are fundamental for neuronal motility, development and regeneration. We used optical tweezers to compare the force exerted by growth cones (GCs) of neurons from the Peripheral Nervous System (PNS), such as Dorsal Root Ganglia (DRG) neurons, and from the Central Nervous System (CNS) such as hippocampal neurons. Developing GCs from dissociated DRG and hippocampal neurons were obtained from P1-P2 and P10-P12 rats. Comparing their morphology, we observed that the area of GCs of hippocampal neurons was 8-10 \ub5m(2) and did not vary between P1-P2 and P10-P12 rats, but GCs of DRG neurons were larger and their area increased from P1-P2 to P10-P12 by 2-4 times. The force exerted by DRG filopodia was in the order of 1-2 pN and never exceeded 5 pN, while hippocampal filopodia exerted a larger force, often in the order of 5 pN. Hippocampal and DRG lamellipodia exerted lateral forces up to 20 pN, but lamellipodia of DRG neurons could exert a vertical force larger than that of hippocampal neurons. Force-velocity relationships (Fv) in both types of neurons had the same qualitative behaviour, consistent with a common autocatalytic model of force generation. These results indicate that molecular mechanisms of force generation of GC from CNS and PNS neurons are similar but the amplitude of generated force is influenced by their cytoskeletal properties

    The role of myosin-II in force generation of DRG filopodia and lamellipodia

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    Differentiating neurons process the mechanical stimulus by exerting the protrusive forces through lamellipodia and filopodia. We used optical tweezers, video imaging and immunocytochemistry to analyze the role of non-muscle myosin-II on the protrusive force exerted by lamellipodia and filopodia from developing growth cones (GCs) of isolated Dorsal Root Ganglia (DRG) neurons. When the activity of myosin-II was inhibited by 30\ue2 ... 1/4M Blebbistatin protrusion/retraction cycles of lamellipodia slowed down and during retraction lamellipodia could not lift up axially as in control condition. Inhibition of actin polymerization with 25\ue2 ...nM Cytochalasin-D and of microtubule polymerization with 500\ue2 ...nM Nocodazole slowed down the protrusion/retraction cycles, but only Cytochalasin-D decreased lamellipodia axial motion. The force exerted by lamellipodia treated with Blebbistatin decreased by 50%, but, surprisingly, the force exerted by filopodia increased by 20-50%. The concomitant disruption of microtubules caused by Nocodazole abolished the increase of the force exerted by filopodia treated with Blebbistatin. These results suggest that; i-Myosin-II controls the force exerted by lamellipodia and filopodia; ii-contractions of the actomyosin complex formed by filaments of actin and myosin have an active role in ruffle formation; iii-myosin-II is an essential component of the structural stability of GCs architecture

    Ergogenic property of Morinda citrifolia L. leaf extract affects energy metabolism in obese Sprague Dawley rats

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    Ergogenic property is the ability to enhance capacity for physical activities through efficient production of energy and is potentially beneficial in weight management for the obese. In this study, ergogenic property of Morinda citrifolia leaf's extract (MCL) was evaluated using AMP-activated protein kinase (AMPK) activity and high fat diet-induced obese rats. Findings from the study showed that MCL demonstrated ergogenic activity via enhancement of AMPK activity using L6 skeletal muscle cell line. Interestingly, the result also revealed that rats treated with the intermediate dosage of MCL experienced the lowest % weight gain. The rats fed the highest dose of 200 mg/kg BW MCL demonstrated the longest swimming time of approximately three times that of green tea and caffeine-fed rats. The highest dose fed rats were also found to have lower glucose and lactate levels, suggesting that energy metabolism was more effective in these rats. In addition, lactate dehydrogenase and creatinine kinase activities, the muscle injury indicators, were found to be the lowest in rats fed the highest MCL dose. The same effect was not seen in rats fed either caffeine or green tea, indicating that MCL treatment is may be protective of the rats' muscles. It was also shown that MCL consisted of various flavonoids with epicatechin, catechin, and quercetin that may be responsible for the effects measured. In conclusion, improvements were seen in rats fed MCL in terms of weight management, endurance capacity, energy metabolism, and muscle injury parameters. PRACTICAL APPLICATIONS: Results of the study revealed that Morinda citrifolia leaf has great potential to be used as functional ingredient in the development of designer food/drink as ergogenic aid for both obese and non-obese individuals. Morinda citrifolia leaf could help in the weight management of obese people and enhance endurance capacity and energy metabolism in active individuals

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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