Research and Evaluation of the Influence of the Construction of the Gate and the Influence of the Piston Velocity on the Distribution of Gases into the Volume of the Casting

Distribution of gasses to the cast volume and volume of pores can be maintained within the acceptable limits by means of correct setting of technological parameters of casting and by selection of suitable structure and gating system arrangement. The main idea of this paper solves the issue of suitability of die casting adjustment—i.e., change of technological parameters or change of structural solution of the gating system—with regards to inner soundness of casts produced in die casting process. Parameters which were compared included height of a gate and velocity of a piston. The melt velocity in the gate was used as a correlating factor between the gate height and piston velocity. The evaluated parameter was gas entrapment in the cast at the end of the filling phase of die casting cycle and at the same time percentage of porosity in the samples taken from the main runner. On the basis of the performed experiments it was proved that the change of technological parameters, particularly of pressing velocity of the piston, directly influences distribution of gasses to the cast volume.     

县级以下综合医疗机构医务人员对现代结控知识的认识现状调查

目的本文旨在了解医务人员现代结控知识掌握的现状及培训效果?方法于培训前后进行问卷调查,内容包括:病例发现?结核病诊断及化疗?结果培训前疫情报告和转诊,回答正确者占75.2%?71.7%;对临床表现?查痰和诊断依据,回答正确者占83.5%?42.5%?40.8%;抗痨药物?用药方法?化疗原则?短化方案?短化疗程?治愈标准六项,回答正确者占58%?14.4%?20.8%?9.2%?17%?24.3%?培训后再次调查发现,90%以上医务人员对现代结控基本知识已掌握?结论各级医务人员现代结控知识是很贫乏的,因此,对其进行系统培训是极为必要的,此项工作省时?省力?投入少,可收到事半功倍的效果。     

Preservation of the pylorus and resection of the head of the pancreas

The historical evolution of the pylorus-preservation resection of the head of the pancreas is traced from the first resections early in this century to relative standardization of the operation, to a lowering of the operative mortality, and to an interest in improving nutritional status after resection. There are many theoretical advantages for the function of the upper gastrointestinal tract after pylorus and gastric preservation, such as maintenance of gastric capacitance and equilibration of osmotic pressure in gastric digestants, foodstuff digestion and absorption, and bowel motility. After the pylorus-preserving resection, gastric emptying is normal, pyloric function to prevent duodenal reflux is often normal, and gastric acids and serum levels of duodenal hormones are at normal levels, whereas after standard pancreatoduodenectomy, all of these are often abnormal. No prospective blinded studies have been published comparing nutritional values after the two operative procedures, but evidence is presented of a satisfactory result with regard to gastric capacitance, body weight gain, and lack of postgastrectomy symptoms. An undoubted advantage of the pylorus-preserving feature is a simplification of the operation. These gains are achieved without increase in operative mortality, without increase in the incidence of jejunal ulcer, and without theoretical or actual decrease in value of the procedure as a cancer operation, except in patients with duodenal carcinoma proximal to the ampulla of Vater.     

Preservation of the pylorus in resection of the head of the pancreas

Pylorus preservation has been advocated to decrease the morbidity associated with the classical or standard pancreaticoduodenectomy. The proposed advantages are decreased incidence of peptic ulceration, dumping syndrome, and nutritional problems. However, after an initial period of enthusiasm for the procedure, it is now being found that marginal ulceration at the duodenojejunal anastomosis is encountered with increasing frequency. Delay in gastric emptying occurs frequently, with an overall incidence of 30%. With the availability of better pancreatic enzyme supplements, the current incidence of nutritional problems and weight loss after the standard Whipple procedure is unknown. Whether there is a difference in long-term survival after the two procedures performed for adenocarcinoma of the head of the pancreas is still debatable. A controlled trial is needed to answer many of these questions, and pylorus-preserving pancreaticoduodenectomy should be used cautiously until further data become available.     

Studies of the vascular anatomy of the mesorectum support the concept of the total mesorectal excision

The relation between the mesorectal vessels and the mesorectal fascia needs to be clarified, as a total mesorectal excision (TME) probably derives its advantage from the fact that the visceral or mesorectal fascia can be regarded as a “tumor-tight packaging” and does not contain anatomically preformed perforations. The purpose of this investigation was to study both rectal arterial supply and vascular distribution pattern within the mesorectum. The arterial supply to the rectum was studied with the injection technique in 12 porcine and 28 human TME specimens. We stain-marked 12 porcine and 15 human specimens. Thirteen human specimens were angiographed after filling their arterial bed with a radio-opaque substance. The superior rectal artery is the main rectal artery. Terminal branches extend downwards and forward around the rectum to the level of the levator and muscle. The superior rectal artery and vein were found to be enclosed in a fibrous sheath. The main mesorectal vessels do not penetrate the mesorectal fascia. This study supports the hypothesis of bilateral somatic and one central visceral compartment in the pelvis and implies the absolute necessity of tumor removal within an intact mesorectal fascia. Received: 15 August 2000 / Accepted in revised form: 1 October 2000     

Characterization of the beta-adrenoceptor of the adipose cell of the rat

The dose-response curves of the beta-adrenergic agonists isoprenaline (mixed beta 1 and beta 2), prenalterol (beta 1-selective), noradrenaline (more beta 1 than beta 2) and salbutamol (beta 2-selective) were studied on adipose cells of the rat, in vitro. The observed lipolytic potencies were in the order: isoprenaline greater than noradrenaline greater than salbutamol greater than prenalterol. The effects of beta-adrenergic antagonists betaxolol (beta 1-selective) propranolol (non-selective) and ICI 118551 (beta 2-selective) on lipolysis stimulated by the various beta-adrenergic agonists showed that in each case propranolol was the most potent blocking agent. These observations are not compatible with the concept that regulation of lipolysis in adipose tissue is mediated exclusively either by adrenergic receptors of the classical beta 1 type, or of the classical beta 2 type. We propose therefore, that this beta-adrenergic receptor, because of its non-compliance with the current classification system, be termed a 'beta-3' or beta-hybrid' adrenoceptor. Thus cardio-selective beta-adrenergic blocking agents, like betaxolol, may offer a hitherto unrecognized clinical advantage in obese patients undergoing anti-hypertensive therapy by offering a reduced impediment to hormone-induced utilization of calorie stores in adipose tissue.     

Evaluation of contractile state of the left ventricle from the peak of the first derivative of the apexcardiogram

Simultaneous records of the electrocardiogram, phonocardiogram, apexcardiogram (ACG), and the first derivative of the apexcardiogram ($\text{dA}\text{dt}$) were obtained in 50 normal subjects and in 38 patients with ischemic heart disease. This allowed us to measure the ratio of peak $\text{dA}\text{dt}$ to total amplitude of the first derivative in percent and the interval from electrical stimulation to peak $\text{dA}\text{dt}$ (R to peak $\text{dA}\text{dt}$). In 16 additional normal subjects the effects of pharmacological agents with positive and negative inotropic action were studied with the above parameters. During isoprenaline infusion the ratio of peak to total amplitude $\text{dA}\text{dt}$ was increased and the interval R to peak $\text{dA}\text{dt}$ was shortened, while after propranolol the ratio of peak $\text{dA}\text{dt}$ diminished and the interval R to peak $\text{dA}\text{dt}$ showed elongation.In normal subjects the ratio of peak $\text{dA}\text{dt}$ averaged 48 ± 14% and it is significantly lower in patients with ischemic heart disease (32 ± 13%, p < 0.001). In controls the interval R to peak $\text{dA}\text{dt}$ was 73 ± 15 msec., whereas in ischemic heart disease it showed elongation (121 ± 15 msec., p < 0.01).It is concluded that the ratio peak $\text{dA}\text{dt}$ and the interval R to peak $\text{dA}\text{dt}$, expressing noninvasively the rate of pressure changes and the duration of the development of maximum tension during isovolumic contraction, provide useful information on left ventricular function.     

A Stereological Study of the Effects of the Pineal Gland on the Ventral Prostate of the Rat

Several procedures known to influence pineal gland secretion were studied for their effects on the ventral prostate of rats. Stereological measurements were made of volume fractions of acini and glandular epithelium, surface fractions of glandular epithelium, and length fractions of acini. From these figures and the weights of the glands, the volumes, surface areas, and lengths of these features were calculated, as well as the mean epithelial heights, mean acinar diameters, and mean distances between glandular acini. None of these measurements differed in sham-operated controls, pinealectomized, or blinded rats. In blind-anosmic rats, however, there were significant decreases in the weights of the prostates and the volumes of the acini, reflecting significant decreases in the mean diameters of acini. None of the other parameters differed from those of controls, except the length fraction of acini. These results differ from those described by others following castration in rats, indicating that the action of the pineal gland on the ventral prostate may be different from that of androgen deprivation, in this species. Caution should therefore be exercised in the interpretation of the results of experiments in which prostate weights are used as indications of the actions of pineal hormones on the neuroendocrine-gonadal axis.