Simulation of Dynamic and Meta-Dynamic Recrystallization Behavior of Forged Alloy 718 Parts Using a Multi-Class Grain Size Model.

Dynamic and meta-dynamic recrystallization occur during forging of alloy 718 aircraft parts and thus change the microstructure during a multistep production route. Since the prediction of the resulting grain structure in a single grain fraction is not able to describe microstructures with bimodal or even multimodal distributions, a multi-class grain size model has been deployed to describe the recrystallization mechanisms during thermomechanical treatments and predict the resulting grain size distributions more accurately. As forging parameters, such as temperature, strain rate and maximum strain influence the flow curve and consequently the recrystallization behavior, a series of double cone compression experiments has been carried out and used to verify and adapt the material parameters for the multi-class grain size model. The recrystallized fractions of the numerical and experimental results are compared and differentiated in view of the recrystallization mechanism, i.e., dynamic and meta-dynamic recrystallization. The strong dependence of the recrystallization kinetics on the initial grain size is highlighted, as well as the influence of different strain rates, which shall represent typical forging equipment.

Histological features of gastric cardia in adults: an autopsy study.

BACKGROUND AND AIMS: The existence, histology and origin of gastric cardiac mucosa are controversial. The aim of the present study was to determine the existence, histological characteristics and length of cardiac mucosa and to correlate these features with the patients' age and the presence of inflammation in the gastric cardia and/or esophagus. METHODS; The cardiac mucosa within the whole esophagogastric junction was histologically analyzed in 38 consecutive autopsy specimens and measured in 24 cases. RESULTS: The cardiac mucosa was identified in all specimens from all cases, with a mean length of 6.7 mm, range 0.927-19.5 mm. In the majority of cases, the length of cardiac mucosa was less than 10 mm (87.5%) and greater than 5 mm (71%). Cardiac mucosa was composed of a combination of pure mucous glands and mucous glands with parietal cells in 74% of cases, and only of mucous glands with parietal cells in 26% of cases. Carditis was recorded in 23.7% cases and reflux esophagitis in 15.8%. The length of cardiac mucosa was not significantly different between cases with and without carditis (p>0.05), between those with and without esophagitis (p>0.05), and between age groups older and younger than 60 years (p>0.05). CONCLUSION: In the adult population, a short histological segment of gastric cardia was consistently present as a normal histological structure. The type, length and circumferential presence of cardiac mucosa were not significantly associated with carditis, esophagitis or age.

A case of a fatal Himalayan black bear attack in the zoo.

We present a case of a 22-year-old male, who was found inside the cage of Himalayan black bears in the Belgrade Zoo. The victim attended the Belgrade Beer festival the previous night, drinking a lot of beer and acting aggressively. A medico-legal autopsy was performed at the Institute of Forensic Medicine in Belgrade. Autopsy findings showed numerous excoriations all over the body surrounded by bruises, as well as spindle-shaped, oval, and partly irregular wounds of variable size, large defects of skin and subcutaneous soft tissue, fractures of the thyroid and cricoid cartilage, and fracture of ribs. Postmortem toxicological analysis revealed the presence of ethanol in vitreous humor and urine and 11-nor Δ9 tetrahydrocannabinolic acid found in the urine. We discussed similar cases from the available literature in different regions of the world. In conclusion, we pointed out that the presented case does not follow the general pattern of Himalayan bear attacks.

Divergent patrilineal signals in three Roma populations.

Previous studies have revealed that the European Roma share close genetic, linguistic and cultural similarities with Indian populations despite their disparate geographical locations and divergent demographic histories. In this study, we report for the first time Y-chromosome distributions in three Roma collections residing in Belgrade, Vojvodina and Kosovo. Eighty-eight Y-chromosomes were typed for 14 SNPs and 17 STRs. The data were subsequently utilized for phylogenetic comparisons to pertinent reference collections available from the literature. Our results illustrate that the most notable difference among the three Roma populations is in their opposing distributions of haplogroups H and E. Although the Kosovo and Belgrade samples exhibit elevated levels of the Indian-specific haplogroup H-M69, the Vojvodina collection is characterized almost exclusively by haplogroup E-M35 derivatives, most likely the result of subsequent admixture events with surrounding European populations. Overall, the available data from Romani groups points to different levels of gene flow from local populations.

In the absence of dental records, do we need forensic odontologists at mass grave sites?

With the exception of exhumations of mass graves in Latin America, forensic dentists and odontologists are rarely involved in the examination of mortal remains recovered from mass graves. The cited reason is often that "there are no dental records-so what is the point"? In this presentation we review the published accounts of examination of remains arising from the conflict in the former Yugoslavia between 1991 and 1999 in which dental examinations are reported. There are roughly 30,000 missing persons of which more than 15,000 mortal remains have been identified, mostly based on DNA. There are 9 sources which describe postmortem dental examinations of 3919 sets of remains; of these, 23% were purported to have been identified specifically from dental information. Of the 8100 listed missing persons from the Srebrenica mass killings in 1995, we located 600 dental records. A sample of 263 charts was examined for information about first molar treatment as we are concerned that dental charting of individuals who lose their first molars may be incorrectly done if allowance is not made for mesial drift of the remaining molars. We found that of all the first molar extractions that are ever going to occur according to these dental charts, 63% have taken place by age 18. The majority of extracted first molars have a functional age of 17 years. We observe that an adult's remains from Srebrenica usually have only second and third molars, which have often drifted forward to occupy the position of the first molar creating the appearance of third molar agenesis. We conclude: that, since dental identifications of victims in mass graves and mass disasters is the exception rather than the rule, even in the absence of DNA-based identifications, international forensic odontologists have an ethical obligation to become more involved in examination of mass grave victims, that there must be more determined searches for antemortem dental records; that local dentists should be approached to participate in the examination of remains and lastly that dental examination and charting by anthropologists and pathologists may be grossly inaccurate. Furthermore, even in the absence of dental records, there is significant information about the individual to be obtained by an oral biologist since many families have useful memories about the oral status of their loved ones who went missing.

[Subarachnoidal hemorrhage from saccular aneurysms as a cause of natural death]. / Subarahnoidalno krvavljenje iz sakularnih aneurizmi kao uzrok prirodne srmti.

INTRODUCTION: Subarachnoidal hemorrhage (SAH) is the fourth most common intracranial cause of death. Approximately 50 to 85 percent of non-traumatic SAH is caused by rupture of congenital berry aneurysm. Symptoms of rupture are typically sudden and without any heralds. In most SAH cases, the vasospasm following the rupture is the most probable cause of death. In forensic pathology, an isolated SAH episode after minor head trauma should be considered dubious, and as mode of death. OBJECTIVE: The objective of this paper was to establish the frequency of sudden natural death caused by SAH originating from ruptured berry aneurysm and to establish the epidemiologic characteristics of the deceased, as well as pathoanatomic characteristics of ruptured aneurysms. MATERIAL AND METHOD: A retrospective autopsy study of the material of the Institute of Forensic Medicine in Belgrade was performed over a period of eighteen years. Some risk factors were estimated: smoking habits, hypertension, alcoholism, and stress 24 hours preceding the rupture. The following pathoanatomic features of berry aneurysms were determined: localization, size, number, spread to surrounding structures and any association with atherosclerosis of brain blood vessels. RESULTS: The analyzed sample consisted of 63 examined individuals: 33 male and 30 female. Their age ranged from 9 to 89 years, with mean age of 46.2 +/- 14.5 years. In our sample, there were 47 smokers (25 male and 22 female), 41 individuals who suffered from hypertension (22 male and 19 female), and 15 alcoholics (14 male and one female). In our sample, physical or mental stress preceded the berry aneurysm's rupture in 26 cases. Most of fatal berry aneurysms were localized in the anterior part of the circle of Willis (41 of them): 20 of them were localized in bifurcations. In 46 cases, the berry aneurysms were less than 5 mm in diameter, in 10 cases with a diameter measuring 5 to 10 mm and in 7 cases the aneurysms were larger than 10 mm in diameter. The association with macroscopically visible atherosclerotic lesions of the arteries of the circle of Willis was evident in 34 cases. Nine people had multilocular berry aneurysms. Polycystic kidney disease associated with berry aneurysms was evident in nine cases. DISCUSSION: The difference between the number of males and females in our sample was not statistically significant (c2=0.014; p>0.10). The age of the deceased mostly ranged from 30 to 60 years. There was no significant difference between the mean age of the males and females in our sample (t=1.65; p>0.05). In our sample, statistically significant localization of fatal berry aneurysm was the anterior part of the circle of Willis (c2=5.74; p<0.05). The frequency of the berry aneurysms larger than 10 mm in diameter was less significant than those with smaller diameters (c2=31.10; p<0.001). The individuals in our sample with aneurysms smaller than 5 mm in diameter were not significantly younger than individuals with larger ones (t=0.98; p>0.05). The number of individuals in our sample with berry aneurysms associated with atherosclerotic lesions was not statistically significant (c2=0.32; p>0.1). CONCLUSION: Sometimes, it is not possible to detect the exact localization of the ruptured berry aneurysm: the rupture may destroy the aneurysm completely. In such case, an autopsy should rule out other possible sources of intracranial bleeding, such as vascular malformations, intraventricular spreading of intracerebral hematomas, neoplasia, hematological disorders, etc.