Design and implementation of a Thomson parabola for fluence dependent energy-loss measurements at the Neutralized Drift Compression eXperiment.

The interaction of ion beams with matter includes the investigation of the basic principles of ion stopping in heated materials. An unsolved question is the effect of different, especially higher, ion beam fluences on ion stopping in solid targets. This is relevant in applications such as in fusion sciences. To address this question, a Thomson parabola was built for the Neutralized Drift Compression eXperiment (NDCX-II) for ion energy-loss measurements at different ion beam fluences. The linear induction accelerator NDCX-II delivers 2 ns short, intense ion pulses, up to several tens of nC/pulse, or 1010-1011 ions, with a peak kinetic energy of ∼1.1 MeV and a minimal spot size of 2 mm FWHM. For this particular accelerator, the energy determination with conventional beam diagnostics, for example, time of flight measurements, is imprecise due to the non-trivial longitudinal phase space of the beam. In contrast, a Thomson parabola is well suited to reliably determine the beam energy distribution. The Thomson parabola differentiates charged particles by energy and charge-to-mass ratio, through deflection of charged particles by electric and magnetic fields. During first proof-of-principle experiments, we achieved to reproduce the average initial helium beam energy as predicted by computer simulations with a deviation of only 1.4%. Successful energy-loss measurements with 1 µm thick silicon nitride foils show the suitability of the accelerator for such experiments. The initial ion energy was determined during a primary measurement without a target, while a second measurement, incorporating the target, was used to determine the transmitted energy. The energy-loss was then determined as the difference between the two energies.

Development and testing of a pulsed helium ion source for probing materials and warm dense matter studies.

The neutralized drift compression experiment was designed and commissioned as a pulsed, linear induction accelerator to drive thin targets to warm dense matter (WDM) states with peak temperatures of ∼1 eV using intense, short pulses (∼1 ns) of 1.2 MeV lithium ions. At that kinetic energy, heating a thin target foil near the Bragg peak energy using He(+) ions leads to more uniform energy deposition of the target material than Li(+) ions. Experiments show that a higher current density of helium ions can be delivered from a plasma source compared to Li(+) ions from a hot plate type ion source. He(+) beam pulses as high as 200 mA at the peak and 4 µs long were measured from a multi-aperture 7-cm-diameter emission area. Within ±5% variation, the uniform beam area is approximately 6 cm across. The accelerated and compressed pulsed ion beams can be used for materials studies and isochoric heating of target materials for high energy density physics experiments and WDM studies.

Droplet evolution in expanding flow of warm dense matter.

We propose a simple, self-consistent kinetic model for the evolution of a mixture of droplets and vapor expanding adiabatically in vacuum after rapid, almost isochoric heating. We study the evolution of the two-phase fluid at intermediate times between the molecular and the hydrodynamic scales, focusing on out-of-equilibrium and surface effects. We use the van der Waals equation of state as a test bed to implement our model and study the phenomenology of the upcoming second neutralized drift compression experiment (NDCX-II) at Lawrence Berkeley National Laboratory (LBNL) that uses ion beams for target heating. We find an approximate expression for the temperature difference between the droplets and the expanding gas and we check it with numerical calculations. The formula provides a useful criterion to distinguish the thermalized and nonthermalized regimes of expansion. In the thermalized case, the liquid fraction grows in a proportion that we estimate analytically, whereas, in case of too rapid expansion, a strict limit for the evaporation of droplets is derived. The range of experimental situations is discussed.

Sudden death due to undiagnosed Wilms' tumor in an adult.

Sudden unexpected deaths due to natural causes constitute a large number of cases encountered by the forensic pathologist. In a majority of such cases, heart disease is responsible for sudden death. Rare disease entities resulting in sudden death are occasionally encountered and may not fit the classic epidemiological profile. We present a case of sudden death due to a previously undiagnosed Wilms' tumor (WT) in an adult. The pathology of WT is discussed, as is the topic of sudden death due to previously unrecognized malignancy.

Deaths and injuries from house fires.

BACKGROUND: We sought to define the factors associated with house fires and related injuries by analyzing the data from population-based surveillance. METHODS: For 1991 through 1997, we linked the following data for Dallas: records from the fire department of all house fires (excluding fires in apartments and mobile homes), records of patients transported by ambulance, hospital admissions, and reports from the medical examiner of fatal injuries. RESULTS: There were 223 injuries (91 fatal and 132 nonfatal) from 7190 house fires, for a rate of 5.2 injured persons per 100,000 population per year. Rates of injury related to house fires were highest among blacks (relative risk, 2.8; 95 percent confidence interval, 2.1 to 3.6) and in people 65 years of age or older (relative risk, 2.6; 95 percent confidence interval, 1.9 to 3.5). Census tracts with low median incomes had the highest rates of injury related to house fires (relative risk as compared with census tracts with high median incomes, 8.1; 95 percent confidence interval, 2.5 to 32.0). The rate of injuries was higher for fires that began in bedrooms or living areas (relative risk, 3.7); that were started by heating equipment, smoking, or children playing with fire (relative risk, 2.6); or that occurred in houses built before 1980 (relative risk, 6.6). Injuries occurred more often in houses without functioning smoke detectors (relative risk, 1.5; 95 percent confidence interval, 1.0 to 2.4). The prevalence of functioning smoke detectors was lowest in houses in the census tracts with the lowest median incomes (P<0.001). CONCLUSIONS: Rates of injuries related to house fires are highest in elderly, minority, and low-income populations and in houses without functioning smoke detectors. Efforts to prevent injuries and deaths from house fires should target these populations.

Death due to microvascular occlusion in sickle-cell trait following physical exertion.

The heterozygous condition characterized by the presence of hemoglobin AS (sickle-cell trait) occurs in approximately 8% of the American black population. Unlike the homozygous state (sickle-cell disease), sickle-cell trait is not widely recognized as a cause of life-threatening illness or death despite over 30 case reports describing fatal or serious complications of exercise in young black males with this condition. These reports identify heat stress, dehydration, viral illness, and poor physical conditioning as factors which may contribute to exertional rhabdomyolysis and sudden death, suggesting multifactorial etiology. However, since sickling is known to occur postmortem, it remains controversial as to whether the pathogenesis of these exercise related deaths involves microvascular obstruction by sickled erythrocytes. We describe three young black individuals with no significant past medical history who died following physical exertion. In all three cases, postmortem hemoglobin electrophoresis demonstrated hemoglobin AS. In none of the cases was the body temperature found to be elevated. These cases serve to remind the forensic community that, in the proper setting, sickle-cell trait must be viewed as a potentially fatal disorder.

Familial filicide and filicide classification.

Filicide is the killing of a child by his or her parent. Despite the disturbing nature of these crimes, a study of filicide classification can provide insight into their causes. Furthermore, a study of filicide classification provides information essential to accurate death certification. We report a rare case of familial filicide in which twin sisters both attempted to kill their respective children. We then suggest a detailed classification of filicide subtypes that provides a framework of motives and precipitating factors leading to filicide. We identify 16 subtypes of filicide, each of which is sufficiently characteristic to warrant a separate category. We describe in some detail the characteristic features of these subtypes. A knowledge of filicide subtypes contributes to interpretation of difficult cases. Furthermore, to protect potential child homicide victims, it is necessary to know how and why they are killed. Epidemiologic studies using filicide subtypes as their basis could provide information leading to strategies for prevention.

A comparative morphological study of human germ cells in vitro or in situ within seminiferous tubules.

For many infertile couples, intracytoplasmic germ cell/spermatozoon injection into unfertilized eggs may be their only hope for producing their own biological children. Thus far, success with injection of pre-spermatozoan germ cells such as round spermatids has not been as great as that of spermatozoon injection. This could be due in part to the difficulty of identifying younger (less mature) male germ cells in testicular biopsy dispersions. To improve the identification of various types of live, dispersed, human testicular cells in vitro, a comparative study of the morphological characteristics of human spermatogenic germ cells in vitro or in situ within seminiferous tubules was conducted. Live human testicular tissue was obtained from an organ-donating, brain-dead person with a high density of various germ cells. A cell suspension was obtained by enzymatic digestion, and cells were cultured for 3 days in an excessive volume (100-fold medium:cells; v:v) of HEPES-TC 199 medium at 5 degrees C and observed live with Nomarski optics (interference-contrast microscopy). For comparative purposes, testes from ten men obtained at autopsy were fixed, embedded in epoxy resin, sectioned at 20 microm, and observed unstained by Nomarski optics. This approach allowed comparison of morphological characteristics of individual germ cells seen in vitro or in situ in the human testis. In both live and fixed preparations from control men with varied daily sperm production rates, Sertoli cells have oval to pear-shaped nuclei with indented nuclear envelopes and large nucleoli, which makes their appearance distinctly different from germ cells. The size, shape, and chromatin pattern of nuclei, and the presence of meiotic metaphase figures, acrosomic vesicles/structures, tails, and/or mitochondria in the middle piece of germ cells are characteristically seen in live cells in vitro and in those cells observed in the fixed seminiferous tubules. Hence, this comparative approach allows verification of the identity of individual germ cells seen in vitro and provides a checklist of distinguishing characteristics of live human germ cells, to be used by scientists and technical staff in infertility clinics when selecting specific germ cells from a testicular aspirate or enzymatically digested biopsy.

Death due to thrombotic thrombocytopenic purpura in pregnancy: case report with review of thrombotic microangiopathies of pregnancy.

Maternal death during pregnancy, although uncommon, may result from a broad range of conditions. In this paper, a case of thrombotic thrombocytopenic purpura diagnosed by postmortem examination is presented. Thrombotic thrombocytopenic purpura is one of a subset of diseases that result in the formation of microthrombi within the vasculature, either as a primary or secondary manifestation. Other conditions included in the differential diagnosis during pregnancy are hemolytic uremic syndrome, systemic lupus erythematosus, preeclampsia-eclampsia and the HELLP syndrome, acute fatty liver of pregnancy, antiphospholipid antibody syndrome, and disseminated intravascular coagulation. The histologic manifestations of these diseases can be similar and in most cases do not provide adequate information to accurately differentiate these diseases in the postmortem period. This paper addresses the need for clinical history (i.e., symptomatology, trimester of onset) and antemortem laboratory testing in addition to a thorough autopsy to accurately differentiate among the conditions named previously. In the absence of an adequate clinical history and antemortem laboratory testing, the more general diagnosis of "thrombotic microangiopathy of pregnancy" is acceptable.

Contact gunshot wound of the head: diagnosis after surgical debridement of the wound.

A case of homicidal contact gunshot wound of the head is described. The victim survived approximately 1 day and one-half following the shooting, during which time the bullet was recovered during surgery, the injuries were 'well-documented', and surgical debridement of the wound destroyed any visible evidence of gunshot residue on the scalp or underlying bone. Autopsy revealed a skull fragment with soot deposition within the depths of the injured brain, allowing an accurate determination of range-of-fire. The case reiterates the importance of performing autopsies on all homicides.

Familial thoracic aortic aneurysms and dissections.

Rupture of thoracic aortic aneurysms and/or dissections is not rare, occurring in approximately 0.6% of all medicolegal autopsies. Most forensic pathologists are aware of the association between thoracic aortic aneurysms/dissections and trauma, atherosclerosis, inflammation and Marfan syndrome. In this report, we discuss a familial form of thoracic aortic dilatation and/or dissection that is distinct from Marfan syndrome. In addition, we review the topic of thoracic aortic aneurysm and dissection and encourage family notification by forensic pathologists when familial forms of aortic disease are suspected at autopsy.

Immersion technique for brain removal in perinatal autopsies.

Perinatal autopsies present forensic patholgists with a variety of challenges, not the least of which involves the removal and examination of very small and sometimes fragile organs. Removal of the immature brain can be particularly troublesome. Even if great care is taken during brain removal, one is often left with no more than a semifluid amorphous mass of softened tissue by the time the brain is ready to be fixed in formalin. We describe a method of perinatal brain removal which helps to preserve brain shape and integrity. By removing the brain while the head (and body) is totally immersed in water, we find that the brain is easier to remove and less apt to destruction. Subsequent fixation in formalin results in well-preserved, intact specimens, allowing for optimal examination and sectioning.

Fatal anaphylaxis due to fire ant stings.

Imported fire ants (Solenopsis invicta and Solenopsis richteri) are the source of a potentially lethal environmental hazard in the southeastern United States. Because of their resistance to natural and chemical control, fire ants can overwhelm their environment, causing destruction of land and animals. Fire ants can also cause a variety of health problems in humans, ranging from simple stings to anaphylaxis and death. We present a case of a 30-year-old woman who died of anaphylaxis following multiple fire ant stings. At autopsy, multiple skin lesions characteristic of those produced by fire ant stings were present on her arm. Postmortem blood samples were positive for imported fire ant venom-specific IgE antibodies (5654 ng/ml) and tryptase (12 ng/ml). Deaths caused by imported fire ant stings are rare but are likely to become more common as the fire ant population expands. In this report, we review deaths due to fire ant stings, discuss postmortem laboratory findings, and stress the importance of recognizing the characteristic skin lesions produced by fire ants.

Sudden death due to obstruction of coronary artery ostium by aortic valve papillary fibroelastoma.

Papillary fibroelastomas are rare endocardial growths that most commonly occur on the cardiac valves. Whether papillary fibroelastomas represent true neoplasms, hamartomas, or degenerative changes is debatable. Whatever their origin, papillary fibroelastomas have a characteristic gross and microscopic appearance, are usually solitary, and are almost always incidental findings at autopsy or during cardiac surgery. We report a case of sudden death caused by occlusion of the right coronary artery ostium by a papillary fibroelastoma of the aortic valve. We discuss the gross and microscopic features, differential diagnosis, and etiology and pathogenesis of this rare and interesting cardiac lesion.

A suicide disguised as a homicide: return to Thor Bridge.

Suicides staged as homicides are uncommon. We present a case of a self-inflicted gunshot wound of the chest disguised by the victim as a homicide, using a method described by Sir Arthur Conan Doyle in his Sherlock Holmes story, "The Problem of Thor Bridge."

Ethnic differences in testicular structure and spermatogenic potential may predispose testes of Asian men to a heightened sensitivity to steroidal contraceptives.

Spermatogenesis in Asian men appears to be more susceptible to suppression by steroidal contraceptives administered in clinical trials than spermatogenesis in Caucasian men. The objective of this study was to determine whether ethnic differences exist in testicular structure and spermatogenic potential that might predispose Asians to a high sensitivity to steroidal contraceptives. Testes from 12 Chinese men were compared to those from 8 Hispanic men and 12 non-Hispanic Caucasian men of ages 29+/-3, 30+/-2, and 29+/-3 years, respectively. Testes were fixed by vascular perfusion with glutaraldehyde, further fixed in osmium, embedded in Epon, and evaluated by stereology using 0.5-microm sections stained with toluidine blue. Homogenates of fixed testes were evaluated for the number of Sertoli cells and the daily sperm production based on pachytene primary spermatocytes (PDSP) or spermatids with spherical nuclei (DSP). Paired parenchymal weight was less (P < 0.05) in Chinese men than in Hispanic or Caucasian men. The PDSP per gram of parenchyma was lower (P < 0.05) and the DSP per gram tended to be lower in Chinese men than in other groups. The histologic appearance, volume density, and length per man of seminiferous tubules were the same among the ethnic groups; however, the diameter of seminiferous tubules was less (P < 0.05) in Chinese than in Hispanic or Caucasian men. The PDSP per man and the DSP per man were lower (P < 0.05) in Chinese than in Hispanic or Caucasian men. The number of Sertoli cells per gram was higher (P < 0.05) in Chinese or Caucasian men than in Hispanic men, but the number of Sertoli cells per man was lower (P < 0.05) in Chinese men than in Hispanic or Caucasian men. Sertoli cell function, measured as the number of germ cells accommodated by a single Sertoli cell, was lower (P < 0.05) in Chinese men than in Caucasian men. The volume density of Leydig cell cytoplasm was greatest (P < 0.05) in Chinese men, but the number of Leydig cells was similar among the ethnic groups. Hence, smaller testes coupled with reduced Sertoli cell number and function and reduced daily sperm production could predispose Asian men to have a heightened negative response of testes to steroidal contraceptives, as compared to Caucasian men. Dampening (by exogenous androgens) of any physiological benefit to spermatogenesis that a high volume density of Leydig cell cytoplasm may bestow on the human testis (that Asian men may have evolved to require) would exacerbate ethnic differences in the spermatogenic response to hormonal contraceptives.

PIP: Multicenter studies conducted by the World Health Organization suggest that the efficacy of spermatogenesis suppression by hormonal contraception differs across racial and ethnic groups. For both androgens alone and androgens in combination with a progestin, the suppression of spermatogenesis to persistent azoospermia occurred in about 90% of Asian men compared to 60-70% of Caucasians. The present study investigated ethnic differences in testicular structure that may affect the sensitivity of the testis to gonadotropin suppression and the spermatogenic potential of the testis. Testes of 12 healthy Asian men from China who died of sudden traumatic injuries and of 8 Hispanic and 12 Caucasian men from the US who died of the same cause were obtained at autopsy and analyzed. Both paired testicular weight and paired testicular parenchymal weight were significantly lower in Chinese men than Hispanic or Caucasian men. Pachytene primary spermatocytes per gram of parenchyma and spermatids with spherical nuclei also were lower in Chinese men than in the other groups. The histologic appearance, volume density, and length per man of seminiferous tubules were the same across ethnic groups, but the volume of seminiferous tubules per man was significantly lower in Chinese men. The number of Sertoli cells per gram was significantly higher in Chinese and Caucasian men than in Hispanic men, but the number of Sertoli cells per man and Sertoli cell function were significantly lower in Chinese men than the other two groups. The volume density of Leydig cell cytoplasm was greater in Chinese men, but the number of Leydig cells was similar across groups. It is postulated that smaller testes, coupled with the reduced number and function of Sertoli cells and reduced daily sperm production, contribute to an inherently lower spermatogenic potential in Asian men, which predisposes them to a heightened negative spermatogenic response to steroidal contraceptives.

Jejunostomy tube failure: malnutrition caused by intraluminal antegrade jejunostomy tube migration.

Complications occurring with jejunostomy feeding tubes are common and sometimes life-threatening. We describe a case of peristalsis-induced intraluminal antegrade migration of a jejunostomy tube's distal end with concomitant retrograde movement of the small bowel over the tube, which was first discovered at autopsy. This ultimately resulted in the jejunostomy feedings entering the distal ileum, therefore bypassing most of the small intestine. Subsequent malnutrition was a contributing factor in the death of the patient, who had required tube feedings after suffering severe head trauma in a motor vehicle accident 29 months earlier. The only nutritional interventions attempted before death involved various attempts at controlling diarrhea. We discuss the incidence, cause, recognition, and prevention of this rarely reported complication of a "functioning" jejunostomy feeding tube.

Death due to a ruptured berry aneurysm in a 3.5-year-old child.

Berry aneurysms in childhood are rare and have certain characteristics that distinguish them from their adult counterparts. A case of death caused by a ruptured berry aneurysm in a child is presented, and the topic is reviewed.

The implantable cardioverter-defibrillator. A potential hazard for autopsy pathologists.

The implantable cardioverter-defibrillator (ICD) is an implantable electronic device that has been proven to be safe and effective in treating various malignant tachyarrhythmias in susceptible individuals. As the use of ICDs becomes more widespread, more individuals with the implanted devices will be encountered at autopsy. Manipulation of an activated ICD can result in electrical shock. To avoid injury, pathologists must be properly prepared to deal with bodies containing activated ICDs. These devices can also provide valuable information that may be helpful in determining the cause and mechanism of death. Herein, we present information regarding the appropriate guidelines and safeguards for pathologists confronted with an activated ICD.

Cardiac perforation due to Wallstent embolization: a fatal complication of the transjugular intrahepatic portosystemic shunt procedure.

The transjugular intrahepatic portosystemic shunt procedure is an effective intervention for patients with bleeding esophageal varices. Potential complications are numerous but rarely serious. A case of hemopericardium, cardiac tamponade, and death caused by perforation of the right atrium and aorta by a stent after embolization from the liver during stent placement is reported.