Since it is difficult for ultrasonic vibration compound machining to get effective cutting mechanism mathematical model through dynamic analysis,and experimental study is shown an effective method to solve this problem,following researches by means of central composite design(CCD) testing are carried out.4-factor and 3-level SiC wafer ultrasonic vibration compound machining test scheme is designed,and then second-order relational model is established between tangential cutting force,surface roughness,and their main process parameters(wire saw speed,workpiece feed rate,rotational speed,and ultrasonic amplitude) by using response surface methodology.According to multiple quadratic fitting of testing data,quadratic equation of cutting force and surface roughness is obtained.Constrains of actual machining condition upon the parameters are analyzed further.With the goal of improving surface quality(minimized surface roughness) of SiC wafer,the parameters optimization model is established.Particle swarm optimization algorithm and its procedure are designed to solve the model.Test proves that the algorithm could achieve optimized process parameters which satisfy multiple constraints rapidly and effectively.
We study a new system of generalized mixed quasi-variational inequalities in Hilbert space.Using the resolvent operator technique of subdifferential operator,we prove that generalized mixed quasi-variational inequalities are equivalent to the fixed point problems;and we suggest and analyze a new explicit two-step iterative method for this system of generalized mixed quasi-variational inequalities.The new iterative method converge under certain mild conditions.
Chemotherapy-induced neuropathic pain is a distressing and commonly occurring side effect of many commonly used chemotherapeutic agents, which in some cases may prevent cancer patients from being able to complete their treatment. Cannabinoid based therapies have the potential to manage or even prevent pain associated with this syndrome. Pre-clinical animal studies that investigate the modulation of the endocannabinoid system (endogenous cannabinoid pathway) are being conducted to better understand the mechanisms behind this phenomenon. Five recent pre-clinical studies identified from Medline published between 2013 and 2016 were selected for review. All studies evaluated the effect of small-molecule agonists or antagonists on components of the endocannabinoid system in rats or mice, using cisplatin or paclitax-el-induced allodynia as a model of chemotherapy-induced neuropathic pain. Activation of the cannabinoid receptor-2 (CB-2) receptor by AM1710 blocked paclitaxel-induced mechanical and cold allodynia in one study. Four studies investigating the activation of both cannabinoid receptor-1 (CB-1) and CB-2 receptors by dual-agonists (WIN55,21 and CP55,940), or by the introduction of inhibitors of endocannabinoid metabolisers (URB597, URB937, JZL184, and SA-57) showed reduction of chemotherapy-induced al-lodynia. In addition, their results suggest that anti-allodynic effects may also be mediated by additional receptors, including TRPV1 and 5-hydroxytryptamine (5-HT1A). Pre-clinical studies demon-strate that the activation of endocannabinoid CB-1 or CB-2 receptors produces physiological effects in animal models, namely the reduction of chemotherapy-induced allodynia. These studies also provide in-sight into the biological mechanism behind the therapeutic utility of cannabis compounds in managing chemotherapy-induced neuropathic pain, and provide a basis for the conduct of future clinical studies in patients of this population.
Insufficient management of cancer-associated chronic and neuropathic pain adversely affects patient quality of life. Patients who do not respond well to opioid analgesics, or have severe side effects from the use of traditional analgesics are in need of alternative therapeutic op-tions. Anecdotal evidence suggests that medical cannabis has potential to effectively manage pain in this patient population. This review presents a selection of representative clinical studies, from small pilot studies conducted in 1975, to double-blind placebo-controlled trials conducted in 2014 that evaluated the efficacy of cannabinoid-based therapies containing tetrahydrocannabinol (THC) and cannabidiol (CBD) for reducing cancer-associated pain. A review of literature published on Medline between 1975 and 2017 identified five clinical studies that evaluated the effect of THC or CBD on controlling cancer pain, which have been reviewed and summarised. Five studies that evaluated THC oil capsules, THC:CBD oromucosal spray (nabiximols), or THC oromucosal sprays found some evidence of cancer pain reduction associated with these therapies. A variety of doses ranging from 2.7-43.2 mg/day THC and 0-40 mg/day CBD were administered. Higher doses of THC were correlated with increased pain relief in some studies. One study found that significant pain relief was achieved in doses as low as 2.7-10.8 mg THC in combination with 2.5-10.0 mg CBD, but there was conflicting evidence on whether higher doses provide superior pain relief. Some reported side effects include drowsiness, hypotension, mental clouding, and nausea and vomiting. There is evidence suggesting that medical cannabis reduces chronic or neu-ropathic pain in advanced cancer patients. However, the results of many studies lacked statistical power, in some cases due to limited number of study subjects. Therefore, there is a need for the conduct of further double-blind, placebo-controlled clinical trials with large sample sizes in order to establish the optimal dosage and efficacy of different cannabis-based therapies.
Intimal (spindle cell) sarcomas of the left atrium are extremely rare primary cardiac tumours with three cases reported (Li et al. (2013), Cho et al. (2006), and Modi et al. (2009)). We present a 69-year-old man who first came to medical attention after experiencing abdominal discomfort. He had a 30 lb weight loss apparently due to dieting. He denied any other constitutional symptoms. His symptoms persisted despite a course of antibiotics for presumed diverticulitis. Laboratory values were within normal limits, though the haemoglobin was 131 g/L (normal: 140-180). Subsequent abdominal computed tomography (CT) scan revealed an abdominal wall mass and intracardiac lesion; the cardiac mass was further characterized by transesophageal echo (TEE), magnetic resonance imaging (MRI), and dedicated cardiac CT. TEE revealed a mass attached to the posterolateral wall of the left atrium above the mitral annulus, and the cardiac CT and MRI confirmed the TEE findings. The patient underwent extensive surgical resection and repair of the left side of the heart. Postoperatively, he developed acute renal failure requiring dialysis and reintubation for volume overload. He became acutely hypotensive, developed multiorgan failure, and succumbed to his illness. Histopathologic examination of the left atrial mass showed an intimal sarcoma.
To evaluate the diagnositic value of fetal neurosonography combined with magnetic resonance imaging (MRI) in fetal agenesis of corpus callosum (ACC). ACC is a common type of CNS malformation with an estimated prevalence of 1 in 4000–5000. Three-dimensional (3D) ultrasound (US) for evaluating fetal brain structures is possible to diagnose pathological findings of the CNS with increasing accuracy. MRI is most commonly used in the case of abnormal findings regarding the CNS by ultrasound. Between January 2014 and Feburary 2019, 268 fetuses, mean gestational age of 28.3 weeks (range 22-40 weeks), with mild ventriculomegaly and diaphanous diaphragm reduction or disappearance diagnosed at prenatal sonography were included in this study. The detailed fetal neurosonography with 3D/4D analyse and intrauterine fast MRI were performed in the 268 fetuses. Postnatal physical examination and diagnostic imaging were the standard of diagnosis. In 268 fetuses, mean axial diameter of the lateral ventricle was 11.9 mm (range 10-18 mm), 157/268 fetuses (58.58%) showed normal morphology of the lateral ventricles, and the entire corpus callosum was visualised. In 111/268 fetuses (41.42%) were confirmed with ACC. 72 cases were diagnosed by detailed fetal neurosonography, 98 cases by intrauterine MRI and 105 cases were diagnosed by US combined with intrauterine MRI. The sensitivity were 73.87%, 88.28% (p < 0.05) and 94.59% respectively. Detailed fetal neurosonography combined with fast MRI can accurately diagnose fetal ACC, especially improve the detection rate of partial ACC, and provide a reliable basis for clinical diagnosis. 4D US can contribuit to improve the detection rate of ACC, however, the accuracy needs further validation of MRI. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
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