用无血培养基分离空肠弯曲菌的效果研究

空肠弯曲菌是引起急性腹泻的重要病原菌之一。我们于1986年11月至1987年5月应用无血培养基与改良Camp-BAP含血培养基(简称含血培养基)进行已知空肠弯曲菌株及鸡、人肛拭标本在两种培养基上的检出阳性率、染色形态、菌落特征、菌量分布、抑制杂菌等方面的效果研究,取得了满意结果,现报告如下。     

WCG空肠/结肠弯曲菌无血培养基的研究

本研究的WCG无血培养基与Camp-BAP含血培养基同时进行对已知空肠/结肠弯曲菌的培养计数及599份来自鸡和人类粪便标本中空肠/结肠弯曲菌的分离培养试验,结果表明13株已知空肠/结肠弯曲菌在WCG培养基上生长的菌落数(CFU/ml)、菌落形态、菌体特征和生化特性及5次共599份来自鸡和人类粪便标本分离培养取得与Camp-BAP培养基一致或较优的效果。为此,我们认为WCG无血培养基可代替Camp-BAP含血培养基用作培养分离空肠/结肠弯曲菌。     

三种炭疽杆菌选择性培养基的比较实验

炭疽杆菌的分离培养在临床诊断、防疫检验和海关检疫等方面非常重要，常规炭疽杆菌培养基和现有选择性培养基在从污染环境、动物产品等分离炭疽杆菌时，检出率低，且分离时间长。本实验将3种炭疽杆菌选择性培养基，即；Kinsely氏培养基（简称A培养基尸’，梁旭东等以A培养基为基础研制的水杨素琼脂培养基（简称B培养基）”‘和我局以A培养基为基础研制的鲜血琼脂培养基（简称C培养基）’“从各方面进行比较，结果认为C培养基从污染环境、动物产品中分离炭疽杆菌具有检出率高、检出时间短等特』点。1材料与方法1．1培养基A、B、C和普通培…     

土拉菌单克隆抗体的制备及其特性的研究

用土拉弗朗西斯菌疫苗株作为抗原获得了2株单克隆抗体Ftg和Ft44,其抗体亚类分别为IgC2b和IgM,Ft9单抗识别的抗原位点是土拉菌的外膜蛋白,Ft44识别的是脂多糖。2株单抗均可在酶联免疫吸附试验中检出土拉菌,Ft9单抗还可在凝集和免疫荧光试验中与土拉菌发生特异性反应,并不与相关细菌交叉。     

单因素法筛选恩拉霉素发酵培养基

目的 寻找合适的因素和水平,使响应面法优化恩拉霉素发酵培养基时得到较高效价.方法 通过单因素试验,使用干燥滤纸片法优化积累恩拉霉素的摇瓶培养基,即碳氮比、无机盐和生长因子.结果 得到X24培养基,即玉米粉7.50％、葡萄糖0.50％、黄豆粉3.00％、硫酸铵0.40％、玉米浆粉2.00％、硫酸亚铁0.01％、L-乳酸0.20％、碳酸钙0.50％、豆油0.05％、耐高温α-淀粉酶0.07％.该培养基测得最终效价为4 046 u/g,略高于市售恩拉霉素预混剂的效价.结论 此次筛选为下一步培养基的响应面优化打好基础,同时原料易得、配方简便,可满足实验室使用的需求.     

结核分枝杆菌快速培养基研究

本文介绍一种新型的结核分枝杆菌快速培养基,以琼脂为基础,加入适量促进生长因子,快速培养基平均初生长天数由7.8天缩短为2.8天(菌量为10~2mg/ml)。41例痰标本培养,平均初生长天数由20.82天缩短至6.8天,卫生部结核病控制中心和沈阳市结核病防治所,采用改良罗氏培养基和进口BACTEC·460快速培养基作100例标本对照培养,结果本文介绍的快速培养基生长最快,BACTEC·460培养基次之,改良罗氏法最慢,平均生长时间为8.1天,8.9天,23.2天(北京);和5.93天、7.9天、42.2天。(沈阳)。对比差异非常显著(P<0.01);。     

两种新型隐球菌选择性培养基的比较研究

目的比较咖啡酸玉米琼脂培养基(caffeic acid cornmeal agar medium,CACA)和黑米琼脂培养基(black rice agar medium)对鸽粪中新型隐球菌的分离效果。方法用无菌竹签从鸽舍随机采取鸽粪标本,取0.6g与10ml无菌生理盐水制成悬液,然后按每个平板100μl分别接种咖啡酸玉米琼脂培养基和黑米琼脂培养基,肉眼观察菌落形态、颜色,光学显微镜下观察菌体形态,同时用特异性引物CN4和CN5扩增新型隐球菌URA基因,分别统计两种培养基中出现阳性菌株的平板数目。结果黑米琼脂培养基中新型隐球菌菌落呈棕黄色,外观湿润,状似胶汁。共分离获得23株新型隐球菌,检出率32.86%。CACA中新型隐球菌菌落较黑米琼脂培养基上的菌落小,褐色,干燥。共分离出11株新型隐球菌,检出率为15.71%。黑米琼脂培养基的检出率与CACA比较差异有统计学意义(P<0.05),且丝状真菌覆盖性生长的平板数目少于CACA,污染程度低于CACA;通过墨汁染色,在光学显微镜下观察新型隐球菌菌体呈圆形或卵圆形,外有宽厚荚膜,PCR扩增得到了目的条带产物。结论黑米琼脂培养基作为新型隐球菌的选择性培养基其分离培养效果(检出效果和检出率)优于CACA。     

选择培养基分离鼠疫菌的实验研究

开展鼠疫监测以来一直使用营养琼脂培养基、赫氏培养基和龙胆紫血液培养基分离培养鼠疫菌,这些培养基的缺点是选择性差,所有营养条件要求不高的细菌均可生长,鼠疫菌菌落特征不典型,常常与一些杂菌菌落难以辨认。为此,我们选择国际上认可的耶氏菌选择培养基(Yersinia selective     

一种新的空肠弯曲菌培养基的研究

空肠弯曲菌(空弯菌)在FBPCA和Skirrow培养基上,经42℃24和48小时及37和42℃48小时培养,FBPCA上的菌落数接近,均高于Skirrow培养基。100份鸡粪标本42℃24与48小时的检出率,FBPCA无显著性差异(P>0.05),但均显著地高于Skirrow培养基(P<0.005,P<0.05)。 结果提示FBPCA优于Skirrow培养基,可在42℃24小时及37℃48小时分离空弯菌,空弯菌生长较快,菌落大,数量多,且制备简易、价廉。     

LLSⅡ培养基的研制及其效果考核（一种新的沙门氏菌分离培养基）

沙门氏菌（除甲型副伤寒沙门氏菌外），能在ＬＬＳⅡ培养上形成中心黑色边缘红色或橙黄色菌落，而变形杆菌属和枸橼酸杆菌属的细菌因产生Ｈ２Ｓ的特征被抑制而形成黄色菌落达到从菌落形态上就可以把干扰沙门氏菌分离的产Ｈ２Ｓ的非沙门氏菌的细菌区别开，使分离沙门氏菌的准确率大为提高，节省试剂和器材，并简化手续。采集现场的７８０份标本，沙门氏菌的检出率：ＬＬＳⅡ为２６．８％（２０９／７８０），漏检率为０～８．４％，Ｈ     

Studies on the mass action effect of glucose in NIDDM and IDDM: evidence for glucose resistance

Summary The ability of hyperglycaemia to enhance glucose uptake was evaluated in 9 non-insulin-dependent (NIDDM), 7 insulin-dependent (IDDM) diabetic subjects, and in 6 young and 9 older normal volunteers. Following overnight insulin-induced euglycaemia, a sequential three-step hyperglycaemic clamp (+ 2.8 + 5.6, and + 11.2 mmol/l above baseline) was performed with somatostatin plus replacing doses of basal insulin and glucagon, 3-³H-glucose infusion and indirect calorimetry. In the control subjects as a whole, glucose disposal increased at each hyperglycaemic step (13.1 ± 0.6, 15.7 ± 0.7, and 26.3 ± 1.1 μmol/kg · min). In NIDDM (10.5 ± 0.2, 12.1 ± 1.0, and 17.5 ± 1.1 μmol/kg · min), and IDDM (11.2 ± 0.8, 12.9 ± 1.0, and 15.6 ± 1.1 μmol/kg · min) glucose disposal was lower during all three steps (p < 0.05–0.005). Hepatic glucose production declined proportionally to plasma glucose concentration to a similar extent in all four groups of patients. In control subjects, hyperglycaemia stimulated glucose oxidation (+ 4.4 ± 0.7 μmol/kg · min) only at + 11.2 mmol/l (p < 0.05), while non-oxidative glucose metabolism increased at each hyperglycaemic step (+ 3.1 ± 0.7; + 3.5 ± 0.9, and + 10.8 ± 1.7 μmol/kg · min; all p < 0.05). In diabetic patients, no increment in glucose oxidation was elicited even at the highest hyperglycaemic plateau (IDDM = + 0.5 ± 1.5; NIDDM = + 0.2 ± 0.6 μmol/kg · min) and non-oxidative glucose metabolism was hampered (IDDM = + 1.8 ± 1.5, + 3.1 ± 1.7, and + 4.3 ± 1.8; NIDDM = + 0.7 ± 0.6, 2.1 ± 0.9, and + 7.0 ± 0.8 μmol/kg · min; p < 0.05–0.005). Blood lactate concentration increased and plasma non-esterified fatty acid (NEFA) fell in control (p < 0.05) but not in diabetic subjects. The increments in blood lactate were correlated with the increase in non-oxidative glucose disposal and with the decrease in plasma NEFA. In conclusion: 1) the ability of hyperglycaemia to promote glucose disposal is impaired in NIDDM and IDDM; 2) stimulation of glucose oxidation and non-oxidative glucose metabolism accounts for glucose disposal; 3) both pathways of glucose metabolism are impaired in diabetic patients; 4) impaired ability of hyperglycaemia to suppress plasma NEFA is present in these patients. These results suggest that glucose resistance, that is the ability of glucose itself to promote glucose utilization, is impaired in both IDDM and NIDDM patients. [Diabetologia (1997) 40: 687–697] Received: 20 August 1996 and in revised form: 5 March 1997     

血管扩张药物干预下经桡动脉入径应用7 Fr指引导管治疗冠状动脉分叉病变的可行性与安全性

目的评价血管扩张药物干预下经桡动脉入径应用7 Fr指引导管治疗冠状动脉分叉病变的可行性与安全性。方法入选2012年1月至2014年7月经冠状动脉造影示分叉病变且适合行经皮冠状动脉介入治疗(PCI)的患者,随机分成经桡动脉6 Fr指引导管组(6 Fr组)和7 Fr指引导管组(7 Fr组)。对比观察两组患者动脉鞘管置入成功率、手术操作成功率、完成PCI操作时间、X线透视时间和对比剂用量。随访住院期间、术后30 d内的入径血管相关并发症及主要不良心血管事件。结果共纳入229例冠状动脉分叉病变患者,其中6 Fr组113例,7 Fr组116例。两组患者年龄、性别、体重指数、危险因素、临床特征、住院时间等方面比较,差异均无统计学意义。6 Fr组行常规鞘管置入;7 Fr组先行6 Fr鞘管置入,在充分局部麻醉并给予血管扩张药物的基础上更换为7 Fr动脉鞘管。6 Fr组有4例患者换用7 Fr指引导管进行手术操作;7 Fr组均成功完成PCI术,无患者转至6 Fr组。与6 Fr组相比,7 Fr组完成PCI操作时间更短[(52±9.2)min比(60±10.7)min,P0.0001],球囊应用数量更少[(2.9±0.6)枚比(3.2±0.4)枚,P=0.002],X线透视时间更短[(24±8.2)min比(28±9.4)min,P=0.02]。两组对比剂用量比较,差异无统计学意义[(152±25.8)ml比(158±23.5)ml,P=0.20]。住院期间6 Fr组和7 Fr组前臂血肿[4/113例(3.5%)比6/116例(5.2%),P=0.76]及桡动脉闭塞[4/113例(3.5%)比9/116例(7.8%),P=0.26]的发生率分别比较,差异均无统计学意义。术后30 d随访,两组桡动脉闭塞的发生率相似[2/99例(2.0%)比4/103例(3.9%),P=0.70],且均未见掌弓循环障碍的临床表现。结论在血管扩张药物的作用下,桡动脉血管内径增大,可容性增强,利于7 Fr指引导管分叉病变治疗操作,安全可靠,且并未增加血管并发症发生率。     

Studies on the diabetic syndrome of idiopathic haemochromatosis

Summary Intravenous glucose tolerance test, intravenous tolbutamide test, insulin sensitivity and IL A have been investigated in a series of haemochromatosis patients. It appears that decreased carbohydrate tolerance and decreased insulin sensitivity are present in all subjects. — Serum IL A is within or above normal range and increases after tolbutamide administration. On the basis of the data shown, it is suggested that the decreased carbohydrate tolerance occurring in haemochromatosis is due to impaired peripheral glucose utilization, rather than to pancreatic insular insufficiency as postulated by several authors.

---

Untersuchungen des diabetischen Syndroms bei Patienten mit Hämochromatose

Zusammenfassung In einer Serie von Patienten mit Hämochromatose wurde der intravenöse Glucosetoleranztest, der intravenöse Tolbutamidtest, die Empfindlichkeit gegen Insulin und die insulinähnliche Aktivität des Blutes (ILA) untersucht. — Alle Patienten zeigten eine verminderte Kohlenhydrat-Toleranz und eine herabgesetzte Insulinempfindlichkeit. — Die insulinähnliche Aktivität des Serums lag innerhalb oder oberhalb des Normalbereichs und stieg nach Gabe von Tolbutamid an. — Auf Grund der vorgelegten Ergebnisse kann man vermuten, daß die verminderte Kohlenhydrat-Toleranz bei Patienten mit Hämochromatose eher durch einen herabgesetzten peripheren Glucoseverbrauch als durch eine, von verschiedenen Autoren beschriebene Insuffizienz des Inselapparates verursacht wird.

---

Etudes du syndrome diabétique des hémochromatoses idiopathiques

Résumé On a étudié chez des malades atteints d'hémochromatose idiopathique, le test de tolérance au glucose intraveineux, le test au tolbutamide intraveineux, la sensibilité à l'insuline et l'activité insulinique du sérum (ILA). — Tous les sujets présentaient une diminution de la tolérance au glucose et une sensibilité diminuée à l'insuline. — L'activité insulinique du sérum était à des valeurs normales ou supranormales et augmentait après l'administration de tolbutamide. — Sur la base des résultats obtenus, il est suggéré que la diminution de la tolérance au glucose qui se manifeste dans l'hémochromatose est due plutôt à une altération de l'utilisation périphérique du glucose qu'à l'insuffisance insulaire pancréatique, comme cela a été soutenu par plusieurs auteurs.

     

Studies on the mechanism of xylitol-induced insulin secretion in dogs

Summary The effect of infusion of small doses of xylitol into the pancreatic artery upon insulin release was studied in anaesthetized dogs, in order to decide whether the strong insulin-releasing effect of xylitol in dogs is mediated by a direct action of xylitol upon the islets or indirectly by some of its metabolites. Xylitol or glucose was infused at 0.5–1.0 mg/kg · min either into the femoral vein or into the superior pancreaticoduodenal artery, and the changes in plasma insulin were measured in the superior pancreaticoduodenal vein. Infusion into the pancreatic artery always resulted in a sharp increase in insulin release, whereas intravenous infusion caused no or little increase. Infusion of xylitol into the superior pancreaticoduodenal artery produced a prompt increase in plasma insulin in the superior pancreaticoduodenal vein but not in the splenic vein. These data suggest that xylitol has a direct stimulatory effect upon islet cells. — During intravenous infusion of epinephrine (1.0 g/kg. min), plasma insulin did not increase despite intravenous administration of glucose or xylitol (0.4 g/kg). There was a rebound rise of plasma insulin after cessation of epinephrine infusion. Plasma insulin responses to intravenous injection of glucose or xylitol (0.4 g/kg) were inhibited also by the intravenous infusion of diazoxide (0.2 mg/kg · min), but this was somewhat variable among individual dogs. The suppression by epinephrine or diazoxide of both glucose and xylitol-induced hyperinsulinaemia may suggest that there is some common mechanism between the insulin-releasing effects of glucose and xylitol.

---

Untersuchungen zum Mechanismus der verstärkten Insulinsekretion unter Xylit

Zusammenfassung An anaesthesierten Hunden wurde die Wirkung der Infusion kleiner Xylit-Mengen in die Pankreasarterie auf die Insulinfreisetzung untersucht, um zu klären, ob das Xylit direkt oder über einen seiner Metabolite auf die Insulinausschüttung wirkt. Xylit oder Glucose wurde in Mengen von 0.5–1.0 mg/kg/min entweder in die Femoralvene oder in die A.pankreaticoduodenalis sup. infundiert und die Änderung des PlasmaInsulins in der V.pankreatico-duodenalis sup. gemessen. Zufuhr über die Pankreasarterie löste immer eine abrupte Steigerung der Insulinfreisetzung aus, während intravenöse Gaben zu keinem oder nur einem geringen Anstieg führten. Die Xylit-Infusion in die A.pankreaticoduodenalis sup.bewirkte zwar eine prompte Steigerung der Plasma-Insulinspiegel in der V.pankreatico duodenalis sup., nicht aber in der Milzvene. — Diese Befunde sprechen dafür, daß Xylit die Inselzellen direkt stimuliert. Während einer i.v.Infusion von 1.0 g/kg/min Adrenalin stieg das Plasma-Insulin trotz intravenöser Zufuhr von 0.4 g/kg Glucose oder Xylit nicht an. Nach Beendigung der Adrenalin-Infusion wurde ein verstärkter Wiederanstieg des Plasma-Insulins beobachtet. Auch durch i.v.Gaben von 0.2 mg/kg/min Diazoxid ließ sich die Wirkung der Infusion von 0.4 g/kg Glucose oder Xylit unterdrükken, wobei sich jedoch Unterschiede zwischen den einzelnen Tieren ergaben. Die Aufhebung des Xylit- u. Glucose-Effektes auf die Insulinsekretion durch Adrenalin und Diazoxid könnte darauf hinweisen, daß die Steigerung der Insulinfreisetzung durch Glucose und Xylit auf einem gemeinsamen Mechanismus beruht.

---

Etudes sur le mécanisme de la sécrétion d'insuline provoquée par le xylitol chez des chiens

Résumé L'effet sur la sécrétion d'insuline de l'infusion de petites doses de xylitol dans l'artère pancréatique a été étudié chez des chiens anesthésiés, afin de savoir si l'effet fortement insulino-sécréteur du xylitol chez les chiens est dû à une action directe du xylitol sur les îlots ou à une action indirecte par l'intermédiaire de certains de ses métabolites. Le xylitol ou le glucose était infusé la dose de 0.5–1.0 mg/kg. min, soit dans la veine fémorale, soit dans l'artère pancréatico-duodénale supérieure, et les variations de l'insuline plasmatique étaient mesurées dans la veine pancréatico-duodénale supérieure. L'infusion dans l'artère pancréatique provoquait toujours une rapide augmentation de la sécrétion d'insuline, tandis que l'infusion intraveineuse ne causait pas ou peu d'augmentation. L'infusion de xylitol dans l'artère pancréaticoduodénale supérieure provoquait une augmentation prompte de l'insuline plasmatique dans la veine pancréatico-duodénale supérieure, mais pas dans la veine splénique. Ces données suggèrent que le xylitol a un effet stimulateur direct sur les cellules des îlots. — Pendant l'infusion intraveineuse d'adrénaline (1.0 g/kg. min), l'insuline plasmatique n'augmentait pas malgré l'administration intraveineuse de glucose ou de xylitol (0.4 g/kg). Après l'arrêt de l'infusion d'adrénaline, l'insuline plasmatique présentait un phénomène de rebound. Les réponses de l'insuline plasmatique l'injection intraveineuse de glucose ou de xylitol (0.4 g/kg) étaient également inhibées par l'infusion intraveineuse de diazoxide (0.2 mg/ kg. min), mais ceci était un peu variable selon les chiens. La suppression par l'adrénaline ou le diazoxide de l'hyperinsulinémie provoquée par le glucose et le xylitol peut suggérer qu'il existe un mécanisme commun entre les effets insulino-sécréteurs du glucose et du xylitol.

     

A multivariate logistic regression equation to screen for dysglycaemia: development and validation.

AIMS: To develop and validate an empirical equation to screen for dysglycaemia [impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and undiagnosed diabetes]. METHODS: A predictive equation was developed using multiple logistic regression analysis and data collected from 1032 Egyptian subjects with no history of diabetes. The equation incorporated age, sex, body mass index (BMI), post-prandial time (self-reported number of hours since last food or drink other than water), systolic blood pressure, high-density lipoprotein (HDL) cholesterol and random capillary plasma glucose as independent covariates for prediction of dysglycaemia based on fasting plasma glucose (FPG)>or=6.1 mmol/l and/or plasma glucose 2 h after a 75-g oral glucose load (2-h PG)>or=7.8 mmol/l. The equation was validated using a cross-validation procedure. Its performance was also compared with static plasma glucose cut-points for dysglycaemia screening. RESULTS: The predictive equation was calculated with the following logistic regression parameters: P=1+1/(1+e-X)=where X=-8.3390+0.0214 (age in years)+0.6764 (if female)+0.0335 (BMI in kg/m2)+0.0934 (post-prandial time in hours)+0.0141 (systolic blood pressure in mmHg)-0.0110 (HDL in mmol/l)+0.0243 (random capillary plasma glucose in mmol/l). The cut-point for the prediction of dysglycaemia was defined as a probability>or=0.38. The equation's sensitivity was 55%, specificity 90% and positive predictive value (PPV) 65%. When applied to a new sample, the equation's sensitivity was 53%, specificity 89% and PPV 63%. CONCLUSIONS: This multivariate logistic equation improves on currently recommended methods of screening for dysglycaemia and can be easily implemented in a clinical setting using readily available clinical and non-fasting laboratory data and an inexpensive hand-held programmable calculator.     

Traditional plant treatments for diabetes. Studies in normal and streptozotocin diabetic mice

Summary The effects on glucose homeostasis of eleven plants used as traditional treatments for diabetes mellitus were evaluated in normal and streptozotocin diabetic mice. Dried leaves of agrimony (Agrimonia eupatoria), alfalfa (Medicago saliva), blackberry (Rubus fructicosus), celandine (Chelidonium majus), eucalyptus (Eucalyptus globulus), lady's mantle (Alchemilla vulgaris), and lily of the valley (Convallaria majalis); seeds of coriander (Coriandrum sativum); dried berries of juniper (Juniperus communis); bulbs of garlic (Allium sativum) and roots of liquorice (Glycyrhizza glabra) were studied. Each plant material was supplied in the diet (6.25% by weight) and some plants were additionally supplied as decoctions or infusions (1 g/400 ml) in place of drinking water to coincide with the traditional method of preparation. Food and fluid intake, body weight gain, plasma glucose and insulin concentrations in normal mice were not altered by 12 days of treatment with any of the plants. After administration of streptozotocin (200 mg/kg i.p.) on day 12 the development of hyperphagia, polydipsia, body weight loss, hyperglycaemia and hypoinsulinaemia were not affected by blackberry, celandine, lady's mantle or lily of the valley. Garlic and liquorice reduced the hyperphagia and polydipsia but did not significantly alter the hyperglycaemia or hypoinsulinaemia. Treatment with agrimony, alfalfa, coriander, eucalyptus and juniper reduced the level of hyperglycaemia during the development of streptozotocin diabetes. This was associated with reduced polydipsia (except coriander) and a reduced rate of body weight loss (except agrimony). Alfalfa initially countered the hypoinsulinaemic effect of streptozotocin, but the other treatments did not affect the fall in plasma insulin. The results suggest that certain traditional plant treatments for diabetes, namely agrimony, alfalfa, coriander, eucalyptus and juniper, can retard the development of streptozotocin diabetes in mice.     

Influence of Alloying Elements on the Dynamic Recrystallization of 4 wt.–% Medium Manganese Steels

The hot deformation behaviour of air-hardening martensitic forging steels (of type 1.5132) is presented. The newly developed steels are characterized through dilatometric tests as well as through microstructure analyses with LOM and SEM and hardness measurements. Additionally, the influence of alloying elements on the flow curves at high temperatures is discussed. It is demonstrated that the higher alloying content does not increase the equivalent stresses in comparison to the reference alloys and contrariwise reduces the offset for dynamic recrystallization at temperatures below 1100 ∘C. Furthermore, the effect of different alloying elements on the strain hardening behaviour during hot compression of 4wt.–% medium manganese steels is presented. It is shown that boron reduces the offset for dynamic recrystallization if present in solid solution, while the combined addition of titanium and niobium annihilates the solid drag effect on the prior austenite grain boundaries.