A 500-kiloton airburst over Chelyabinsk and an enhanced hazard from small impactors.

Most large (over a kilometre in diameter) near-Earth asteroids are now known, but recognition that airbursts (or fireballs resulting from nuclear-weapon-sized detonations of meteoroids in the atmosphere) have the potential to do greater damage than previously thought has shifted an increasing portion of the residual impact risk (the risk of impact from an unknown object) to smaller objects. Above the threshold size of impactor at which the atmosphere absorbs sufficient energy to prevent a ground impact, most of the damage is thought to be caused by the airburst shock wave, but owing to lack of observations this is uncertain. Here we report an analysis of the damage from the airburst of an asteroid about 19 metres (17 to 20 metres) in diameter southeast of Chelyabinsk, Russia, on 15 February 2013, estimated to have an energy equivalent of approximately 500 (±100) kilotons of trinitrotoluene (TNT, where 1 kiloton of TNT = 4.185×10(12) joules). We show that a widely referenced technique of estimating airburst damage does not reproduce the observations, and that the mathematical relations based on the effects of nuclear weapons--almost always used with this technique--overestimate blast damage. This suggests that earlier damage estimates near the threshold impactor size are too high. We performed a global survey of airbursts of a kiloton or more (including Chelyabinsk), and find that the number of impactors with diameters of tens of metres may be an order of magnitude higher than estimates based on other techniques. This suggests a non-equilibrium (if the population were in a long-term collisional steady state the size-frequency distribution would either follow a single power law or there must be a size-dependent bias in other surveys) in the near-Earth asteroid population for objects 10 to 50 metres in diameter, and shifts more of the residual impact risk to these sizes.

The psychological challenge of genital injury.

INTRODUCTION: Injuries sustained from Improvised Explosive Devices (IEDs) can have a devastating impact on bodily integrity; physical injuries can be severe and include traumatic amputation of limbs, pelvic fracture, abdominal trauma, extremity fragmentation wounds and genital trauma. Soldiers suffering from genital trauma can experience overwhelming emotions and adjusting to their injuries is a process that occurs over time, that some find easier than others. This paper explores current practice and identifies guidelines for psychological interventions within this arena. METHODS: Relevant associated literature has been reviewed to identify the long-term consequences of genital trauma and to ascertain best practice in supporting this patient population. Current practices within the Royal Centre for Defence Medicine (RCDM) and the Defence Medical Rehabilitation Centre (DMRC) Headley Court have been explored. RESULTS: There is little published literature in this area. Therefore, in respect of guiding treatment of this patient population, related research on the psychological consequences of prostate and penile cancer, limb amputation, acquired infertility and acquired disability has been used as a base to inform interventions. Current practices at RCDM and DMRC have been found to support interventions within related areas. CONCLUSIONS: There is no published evidence base to guide psychological interventions for genital trauma. Professional multidisciplinary intervention will potentially be beneficial in establishing the long-term needs of this patient population, together with qualitative research exploring the experience of soldiers suffering genital trauma.

Assessment of cerebral autoregulation: the quandary of quantification.

We assessed the convergent validity of commonly applied metrics of cerebral autoregulation (CA) to determine the extent to which the metrics can be used interchangeably. To examine between-subject relationships among low-frequency (LF; 0.07-0.2 Hz) and very-low-frequency (VLF; 0.02-0.07 Hz) transfer function coherence, phase, gain, and normalized gain, we performed retrospective transfer function analysis on spontaneous blood pressure and middle cerebral artery blood velocity recordings from 105 individuals. We characterized the relationships (n = 29) among spontaneous transfer function metrics and the rate of regulation index and autoregulatory index derived from bilateral thigh-cuff deflation tests. In addition, we analyzed data from subjects (n = 29) who underwent a repeated squat-to-stand protocol to determine the relationships between transfer function metrics during forced blood pressure fluctuations. Finally, data from subjects (n = 16) who underwent step changes in end-tidal P(CO2) (P(ET)(CO2) were analyzed to determine whether transfer function metrics could reliably track the modulation of CA within individuals. CA metrics were generally unrelated or showed only weak to moderate correlations. Changes in P(ET)(CO2) were positively related to coherence [LF: ß = 0.0065 arbitrary units (AU)/mmHg and VLF: ß = 0.011 AU/mmHg, both P < 0.01] and inversely related to phase (LF: ß = -0.026 rad/mmHg and VLF: ß = -0.018 rad/mmHg, both P < 0.01) and normalized gain (LF: ß = -0.042%/mmHg(2) and VLF: ß = -0.013%/mmHg(2), both P < 0.01). However, Pet(CO(2)) was positively associated with gain (LF: ß = 0.0070 cm·s(-1)·mmHg(-2), P < 0.05; and VLF: ß = 0.014 cm·s(-1)·mmHg(-2), P < 0.01). Thus, during changes in P(ET)(CO2), LF phase was inversely related to LF gain (ß = -0.29 cm·s(-1)·mmHg(-1)·rad(-1), P < 0.01) but positively related to LF normalized gain (ß = 1.3% mmHg(-1)/rad, P < 0.01). These findings collectively suggest that only select CA metrics can be used interchangeably and that interpretation of these measures should be done cautiously.

Does trauma risk management reduce psychological distress in deployed troops?

BACKGROUND: Military personnel exposed to potentially traumatic events whilst deployed on operational duties may develop psychological problems. The Royal Marines have made extensive use of Trauma Risk Management (TRiM), a peer-support system that operates through practitioners embedded within operational units. TRiM aims to promote recognition of psychological illness and to facilitate social support. AIMS: To evaluate the effects of TRiM in two units at different stages of implementation. METHODS: Royal Marines and Army personnel were surveyed prior to, during and upon return from an operational deployment to Afghanistan. Participants completed measures of general mental health (GHQ12) and traumatic stress [PCL(C)]. RESULTS: We received responses from 180 pre-deployment, 105 during deployment and 137 post-deployment. Personnel within units with experience of TRiM reported lower levels of psychological distress than personnel in the unit who were using TRiM for the first time. Both groups reported higher psychological distress scores before and during deployment, compared with post-deployment. However, we found personnel who reported having more access to social support during deployment reported less psychological distress. CONCLUSIONS: The use of TRiM may assist in increasing the psychological resilience of military personnel through the facilitation of social support; this may have particular utility during operational deployments.

Successful treatment of eosinophilic cystitis with benralizumab.

Eosinophilic cystitis is a rare form of interstitial cystitis. It can be chronic and debilitating due to urinary frequency, dysuria, incontinence, and frequent urinary tract infections. Prior attempts at treatment have included oral and intravesical steroids, antispasmodics, and antibiotics when indicated. Treatment of eosinophilic disorders has recently been improved with the use of monoclonal antibodies directed at interleukin 5. We report here a case of eosinophilic cystitis treated with the interleukin 5 antagonist, benralizumab. The patient had significant improvement in both quality of life measures and biopsy findings.

Noise-stabilized random attractor.

A two-dimensional flow model is introduced with deterministic behavior consisting of bursts that become successively larger, with longer interburst time intervals between them. The system is symmetric in one variable and there are bursts on either side of , separated by the presence of an invariant manifold at . In the presence of arbitrarily small additive noise in the direction, the successive bursts have bounded amplitudes and interburst intervals. This system with noise is proposed as a model for edge-localized modes in tokamaks. With noise, the bursts can switch from positive to negative and vice versa. The probability distribution of burst heights and interburst periods is studied, as is the dependence of the statistics on the noise variance. The modification of this behavior as the symmetry in is broken is studied, showing qualitatively similar behavior if the symmetry breaking is small enough. Experimental observations of a nonlinear circuit governed by the same equations are presented, showing good agreement.

Celiac disease and malignancy.

Fifty-five patients with celiac disease and coexistent malignant disease (27 lymphoma, 28 other malignancies) are described. The important clinical features at presentation of lymphoma were weight loss, abdominal pain, diarrhea, profound weakness and fever, associated with anemia, raised ESR, hypoalbuminemia and steatorrhea. There were no specific features to enable earlier diagnosis. Radiology was unhelpful and in no case were malignant cells seen in the jejunal biopsy. Four of the lymphomas were Hodgkin's disease, none of which involved the bowel; the remainder were reticulum cell sarcoma, 17 of which involved the bowel. Definitive diagnosis prior to death was made in only 18 patients, of whom 16 survived from 2 to 226 days (mean, 76 days). Of the remaining two patients, one is still alive, while the other died 26 years after the original diagnosis of Hodgkin's disease. The possibility of lymphoma should be considered in those who present with celiac disease in middle life and in those who deteriorate for no apparent reason after a period of stability on a gluten-free diet. The index of suspicion for lymphoma in celiac disease should be high and early laparotomy be considered in patients with unexplained deterioration. Twenty-eight patients with 29 carcinomas and 3 other tumors are also described. The presentations of these malignancies were no different from their presentations in non-celiac patients, and their development did not provoke a relapse of celiac disease. Considering the whole series of 55 patients, there was little evidence for the view that malignancy itself was the cause of the flat jejunal mucosal appearances seen in these patients.

Effect of choleretics on biliary and urinary excretion of cholecystographic agents.

Two choleretic agents, taurocholate and cinchophen, were studied in the dog to determine their effect on both the biliary and urinary excretion of two related cholecystographic agents, iopanoic acid and iophenoxic acid. Liver concentrations were determined on biopsies. Trace amounts of radioactively labeled compounds were used for measurements. The effect of the choleretic agent was specific for the cholecystographic compound. Taurocholate increased both biliary and urinary excretion of iopanoic acid and decreased its intrahepatic level, but had no effect on iophenoxic acid. Cinchophen had no effect on iopanoic acid but increased both biliary and urinary excretion of iophenoxic acid. When examined against a pre-existing high rate of bile flow, the active choleretic increased, rather than decreased, the biliary concentration of the cholecystographic compound. The increased excretion in both bile and urine cannot be attributed simply to the lessened concentration gradient from plasma to bile, as proposed by others. The data are consistent with a direct action of the choleretic agent on hepatic mechanisms, either to decrease intracellular binding or to alter the characteristics of transport.

Biliary and urinary excretion of iopanoic acid in the dog.

The urinary and biliary excretion of iopanonic acid was studied in anesthetized dogs infused with sodium iopanoate and trace amounts of 125I-iopanoic acid to provide a wide range of plasma concentrations. Samples of kidney and liver were also analyzed for total radioactivity. The sole excretory product in urine and bile was the glucuronide conjugate. The secretory biliary Tm for for iopanoic acid varied between experiments. Biliary concentration far exceeded that of plasma and liver/plasma ratios were all greater than unity. The fractional rate of urinary excretion varied 1-80% and was strongly correlated with hepatic function, e.g. the rate of bile flow. The data are interpreted to indicate that, depending on the rate of bile flow, the glucuronide formed in the liver is partioned between bile and blood, the latter for urinary excretion. This mechanism is discussed in relation to cholecystographic visualization and to the problem of nephrotoxicity.

Biliary and urinary excretion of tyropanoic acid and its Metabolites in the dog.

The biliary and urinary excretion of tyropanoate-derived material was studied in the anesthetized dog with various plasma levels of tyropanoate. Bile, plasma, urine, and hepatic tissue were analyzed by high-pressure liquid chromatography for the presence of tyropanoate, enantiomers of tyropanoate glucuronide, and other typropanoate metabolites. Approximately 90% of the material secreted in the bile was in the form of tyropanoate glucuronide, equally distributed between (+)- and(-)-tyropanoate glucuronide, and approximately 10% was excreted as other tyropanoate-derived metabolites. It is suggested that the choleretic effect associated with the excretion of tyropanoate is associated with the nonglucuronide metabolites. Tyropanoate itself was not secreted into bile. In plasma, approximately 40% of the material was tyropanoate, while approximately 50% existed as tyropanoate glucuronide and 10% as other tyropanoate metabolites. The plasma concentration of (-)-tyropanoate glucuronide was significantly greater than that of (+)-tyropanoate glucuronide. The urinary excretion of tyropanoate-derived material accounted for up to 35% of the total excretion. The primary metabolite in urine was tyropanoate glucuronide. Tyropanoate accounted for less than 5% of the material in urine, whereas other tyropanoate metabolites contributed approximately 20%. The data suggest that there is a stereoselective disposition of tyropanoate metabolites that may influence the overall disposition of the compound.

Systemic aminocaproic acid reduces fibrinolysis in aqueous humor.

Systemically administered aminocaproic acid has been demonstrated to reduce the incidence of secondary hemorrhage in traumatic hyphema. To directly determine the concentration of aminocaproic acid in the aqueous humor, four groups of rabbits were studied following administration of four different regimens of intravenously administered aminocaproic acid. Plasma and aqueous humor samples were assayed for drug content and antifibrinolytic activity. Peak aqueous humor concentrations of aminocaproic acid ranged from 2.5 to 33 mg/dL and varied according to the systemic dose administered. The antifibrinolytic activity paralleled the aminocaproic acid content, with a peak range from 310 to 683 s. These findings indicate a direct relationship between antifibrinolytic activity and the concentration of aminocaproic acid in aqueous humor.

Anticonnective tissue and other antitissue 'antibodies' in the sera of patients with coeliac disease compared with the findings in a mixed hospital population.

Serum IgG specificities directed against various components of basement membrane and reticulin have been described, and their incidence in 138 patients with coeliac disease has been compared with that in 110 hospital inpatients, 100 normal blood donors, and 1441 other patients. A wide variety of antitissue specificities were observed but only a few appeared to be of any significance. The 'antireticulin' specificities have been subdivided into different groups according to their distinctive histological staining patterns. Specificity directed primarily against endothelial basement membrane was found most frequently in the sera of patients with hiatus hernia (35%) or coeliac disease (22%). The same specificity was also observed in patients with myasthenia gravis and to a lesser extent in Crohn's disease and in a mixed group of patients with unspecified organic gastrointestinal disease. An epithelial basement membrane reactivity was found in patients with rheumatoid arthritis but only rarely in other conditions. Staining of perivascular connective tissue represented a third type of 'antireticulin' specificity. It was found only rarely, although in coeliac disease this reactivity was found more frequently in combination with other connective tissue specificities.

Serum lysozyme in inflammatory bowel and coeliac disease.

Serum lysozyme levels were determined by a turbidometric method using egg white lysozyme as standard in 100 patients with Crohn's disease, 86 with ulcerative colitis, 31 with coeliac disease, and in 38 normal control subjects. Though the levels in Crohn's disease were significantly higher than those in ulcerative colitis and in coeliac disease, there was marked overlap between the disorders and control subjects, and so they were of no value in differential diagnosis. There was some evidence that serum lysozyme levels reflected disease activity in Crohn's disease but not in ulcerative colitis.

Folates in human serum.

Constituent serum folates have been shown to be altered and in some cases raised in diseases in which total folate levels are known to be frequently decreased. Absorption experiments showed that orally administered folate analogues affect the folate pool in different ways. The stability of the 10-formyltetrahydrofolate level in normal subjects is demonstrated.

Serum folates in man.

In an aseptic microbiological assay of folate compounds and their breakdown compounds, using Lactobacillus casei, Streptococcus faecalis, and Pediococcus cerevisiae, 4a-hydroxy-5methyl-4,5,6,7-tetrahydrofolate and 5-methyl-5,8-dihydrofolate were inactive under all conditions to all three organisms and 5-methyl-5,6-dihydrofolate was inactive unless ascorbate was present in the incubation medium, and then only to L. casei. 5-Methyltetrahydrofolate was active only for L. casei, and activity in purified samples to S. faecalis was due to trace amounts of folic acid. Analysis of S. faecalis values in the serum in normal subjects and in patients with various disorders showed that levels of 10-formyltetrahydrofolate are raised in coeliac disease, leukaemia, rheumatoid arthritis, and schizophrenia. 5-Methyltetrahydrofolate is readily absorbed by normal human subjects and by patients with pernicious anaemia but poorly absorbed by patients with coeliac disease or leukaemia. 5-Methyl-5,6-dihydrofolate was quickly absorbed by normal human subjects, being reflected by a considerably raised level of 5-methyltetrahydrofolate in serum when sodium bicarbonate was given by mouth before the 5-methyl-5,6-dihydrofolate. These higher levels were comparable to those in patients with pernicious anaemia after oral administration of 5-methyl-5,6-dihydrofolate. Oral 5-methyl-5,8-dihydrofolate and 4a-hydroxy-5-methyl-tetrahydrofolate did not appear as microbiologically active folates in the serum. The findings of this study suggest that the availability for biological utilisation of the major dietary folate compounds will depend on the amount of gastric acidity and of ascorbate in the intestinal chyme. Many may be unavailable for metabolic utilization in the body.

Effect of oral creatine supplementation on power output and fatigue during bicycle ergometry.

Our purpose was to determine the effect of oral creatine supplementation on exercise performance during high-intensity short-duration bicycle sprinting. Power output was recorded for 12 healthy untrained males (age 24.08 +/- 0.53 yr, weight 81.22 +/- 1.32 kg) before and after 5 days of creatine (n = 6) or placebo (n = 6) supplementation. A double-blind research design was employed. Subjects performed maximal sprints against a constant load (111.8 N) for 15 s. Each one-half pedal revolution was magnetically counted, and subsequent measurements of peak power, time to peak power, total work, and the fatigue index were digitized and stored on disk. Mean values for peak power, time to peak power, total work, and fatigue index were 958.01 +/- 40.66 W, 4.09 +/- 0.82 s, 11.28 +/- 0.46 kJ, and 32.1 +/- 1.58% decline from peak power, respectively. No significant differences were observed within or between groups before or after supplementation for any of the mechanical parameters measured (P > 0.05). These findings suggest that oral creatine supplementation does not positively affect power output or fatigue during continuous high-intensity bicycle exercise in untrained men.

Nine months in space: effects on human autonomic cardiovascular regulation.

We studied three Russian cosmonauts to better understand how long-term exposure to microgravity affects autonomic cardiovascular control. We recorded the electrocardiogram, finger photoplethysmographic pressure, and respiratory flow before, during, and after two 9-mo missions to the Russian space station Mir. Measurements were made during four modes of breathing: 1) uncontrolled spontaneous breathing; 2) stepwise breathing at six different frequencies; 3) fixed-frequency breathing; and 4) random-frequency breathing. R wave-to-R wave (R-R) interval standard deviations decreased in all and respiratory frequency R-R interval spectral power decreased in two cosmonauts in space. Two weeks after the cosmonauts returned to Earth, R-R interval spectral power was decreased, and systolic pressure spectral power was increased in all. The transfer function between systolic pressures and R-R intervals was reduced in-flight, was reduced further the day after landing, and had not returned to preflight levels by 14 days after landing. Our results suggest that long-duration spaceflight reduces vagal-cardiac nerve traffic and decreases vagal baroreflex gain and that these changes may persist as long as 2 wk after return to Earth.

The role of grades in gaining admission to highly selective medical schools.

The authors examine the role of grades in the admission decisions at a group of 19 highly selective medical schools by analyzing over 8,000 applications from Cornell University students for the entering medical school classes of 1982 through 1989. The results illustrate the great influence of the grade-point average (GPA) on the admission decision. Between the GPA levels of 3.0 and 3.8, the chance of acceptance increased by a factor of about two for each increment of .2 in the GPA. For a subset of the nine most selective of the 19 institutions, the chance of acceptance increased by a factor of five for each increment of .2. At these nine schools, of 1,157 applications with a GPA of less than 3.4, only four were approved. The authors suggest the evidence indicates that students often receive encouragement to continue the application process even though the chances of eventual acceptance are negligible.

Topical anesthetic before microneurography decreases pain without affecting sympathetic traffic.

Pain associated with the microneurography procedure varies among human research volunteers, and may influence baseline sympathetic neural activity. The purpose of this study was to evaluate the efficacy and effects of applying a topical anesthetic prior to microneurography. Ten volunteers underwent microneurography twice, separated by a minimum of 4 weeks. Using a single-blind, randomized cross-over design, EMLA cream (2.5% lidocaine and 2.5% prilocaine in oil emulsion) or an aqueous placebo cream was applied 2 h prior to each session. Subjects rated pain on a scale from 0 (no pain) to 4 (extreme pain). The electrocardiogram, and efferent sympathetic nerve traffic from peroneal nerve muscle fascicles at the popliteal fossa were recorded during a 10-min supine rest period. EMLA cream significantly reduced perception of pain (P < 0.05), but did not affect burst reflex latencies from preceding R-waves or total muscle sympathetic nerve traffic (P > 0.05). These data show that use of EMLA cream prior to microneurography is innocuous, and do not support the hypothesis that baseline sympathetic traffic is increased by pain or discomfort associated with microneurography.

Writing induces a right hemisphere linguistic advantage in dysphonetic dyslexic children: implications for attention and capacity models of laterality.

An experiment demonstrated a complete hemispheric processing reversal in 10 male, dysphonetic dyslexic children that occurred during a dichotic listening test of their verbal working memory. Requiring a written response to dichotic digits produced a right hemisphere/left ear superiority in the dysphonetic dyslexics whereas normal subjects and other dyslexics maintained a left hemisphere/right ear advantage. This reversal was unaffected by changes in task difficulty. A second experiment assessed the influence on producing the reversal of concurrent manual interference with left hemisphere verbal processing (responding orally vs. manually) and selective right hemisphere priming (Forward Writing vs. Backward Writing). The dysphonetic children reverted to a strong left hemisphere superiority when recalling the dichotic digits orally. Backward writing produced no ear advantage in either direction. The findings suggest that dysphonetic dyslexia may be related to (1) left hemisphere processing demands that exceed capacity, (2) easily activated right hemisphere processing strategies and (3) failure to coordinate linguistic processing interhemispherically. The results supported a novel hybrid conceptualization of dyslexia consisting of a synthesis of selective activation, and dual processor-limited capacity, theories.