Five-day evaluation of the acceptability and comfort of wearable technology at four anatomical locations during military training.

INTRODUCTION: Wearable sensor technologies enable Defence to optimise human performance, remotely identify physiological abnormalities and enhance medical support. Maximising the acceptability of devices will ensure they are worn alongside other equipment. This study assessed the acceptability and comfort of four devices at different anatomical locations during military training. METHOD: A cross-sectional pilot study during a live firing infantry exercise or adventurous training assessed four anatomical locations concurrently over 5 days: finger, wrist, upper arm and chest. Participants rated comfort, acceptability and preference using a standardised questionnaire after 12 hours and 5 days of wear. RESULTS: Twenty-one regular British Army personnel soldiers participated, aged 24.4 (4.3) years. The upper arm location received the highest rating by participants for comfort, followed in order by wrist, finger and chest (p=0.002, Χ2=40.0). The finger was most commonly identified as uncomfortable during specific activities (76%), followed by chest (48%), wrist (23%) and upper arm devices (14%). There was no significant difference in participant confidence in the devices to collect data or allow movement, but there was a trend towards greater confidence in upper arm and wrist locations to stay in position than the others (p=0.059, Χ2=28.0). After 5 days of wear, 43% of participants said they preferred the upper arm for comfort, followed by wrist (36%), finger (24%) and chest (10%). 73% and 71% would wear the wrist and upper arm devices on deployed operations, compared with 29% and 24% for chest and finger devices, respectively. CONCLUSION: The upper arm location offered greater acceptability and comfort than finger, wrist or chest locations. It is essential to consider such findings from occupationally relevant settings when selecting wearable technology. A larger service evaluation in diverse settings is recommended to guide the choice of the most acceptable wearable devices across different equipment, roles and environments.

Validation of dried blood spot sampling for detecting SARS-CoV-2 antibodies and total immunoglobulins in a large cohort of asymptomatic young adults.

BACKGROUND: Detecting antibody responses following infection with SARS-CoV-2 is necessary for sero-epidemiological studies and assessing the role of specific antibodies in disease, but serum or plasma sampling is not always viable due to logistical challenges. Dried blood spot sampling (DBS) is a cheaper, simpler alternative and samples can be self-collected and returned by post, reducing risk for SARS-CoV-2 exposure from direct patient contact. The value of large-scale DBS sampling for the assessment of serological responses to SARS-CoV-2 has not been assessed in depth and provides a model for examining the logistics of using this approach to other infectious diseases. The ability to measure specific antigens is attractive for remote outbreak situations where testing may be limited or for patients who require sampling after remote consultation. METHODS: We compared the performance of SARS-CoV-2 anti-spike and anti-nucleocapsid antibody detection from DBS samples with matched serum collected by venepuncture in a large population of asymptomatic young adults (N = 1070) living and working in congregate settings (military recruits, N = 625); university students, N = 445). We also compared the effect of self-sampling (ssDBS) with investigator-collected samples (labDBS) on assay performance, and the quantitative measurement of total IgA, IgG and IgM between DBS eluates and serum. RESULTS: Baseline seropositivity for anti-spike IgGAM antibody was significantly higher among university students than military recruits. Strong correlations were observed between matched DBS and serum samples in both university students and recruits for the anti-spike IgGAM assay. Minimal differences were found in results by ssDBS and labDBS and serum by Bland Altman and Cohen kappa analyses. LabDBS achieved 82.0% sensitivity and 98.2% specificity and ssDBS samples 86.1% sensitivity and 96.7% specificity for detecting anti-spike IgGAM antibodies relative to serum samples. For anti-SARS-CoV-2 nucleocapsid IgG there was qualitatively 100% agreement between serum and DBS samples and weak correlation in ratio measurements. Strong correlations were observed between serum and DBS-derived total IgG, IgA, and IgM. CONCLUSIONS: This is the largest validation of DBS against paired serum for SARS-CoV-2 specific antibody measurement and we have shown that DBS retains performance from prior smaller studies. There were no significant differences regarding DBS collection methods, suggesting that self-collected samples are a viable sampling collection method. These data offer confidence that DBS can be employed more widely as an alternative to classical serology.

The use of routine blood tests to assist the diagnosis of COVID-19 in symptomatic hospitalized patients.

INTRODUCTION: Specific patterns of blood test results are associated with COVID-19 infection. The aim of this study was to identify which blood tests could be used to assist in diagnosing COVID-19. METHOD: A retrospective review was performed on consecutive patients referred to hospital with a clinical suspicion of COVID-19 over a period of four weeks. The patient's clinical presentation and severe acute respiratory syndrome coronavirus 2 reverse-transcription polymerase chain reaction (SARS-CoV-2 RT-PCR) were recorded. The patients were divided by diagnosis into COVID (COVID-19 infection) or CONTROL (an alternate diagnosis). A retrospective review of consecutive patients over a further two-week period was used for the purposes of validation. RESULTS: Overall, 399 patients (53% COVID, 47% CONTROL) were analysed. White cell count, neutrophils and lymphocytes were significantly lower, while lactate dehydrogenase and ferritin were significantly higher, in the COVID group in comparison to CONTROL. Combining the white cell count, lymphocytes and ferritin results into a COVID Combined Blood Test (CCBT) had an area under the curve of 0.79. Using a threshold CCBT of -0.8 resulted in a sensitivity of 0.85 and a specificity of 0.63. Analysing this against a further retrospective review of 181 suspected COVID-19 patients, using the same CCBT threshold, resulted in a sensitivity of 0.73 and a specificity of 0.75. The sensitivity was comparable to the SARS-CoV-2 RT PCR. DISCUSSION: Mathematically combining the blood tests has the potential to assist clinical acumen allowing for rapid streaming and more accurate patient flow pending definitive diagnosis. This may be of particular use in low-resource settings.

Does vitamin D supplementation prevent SARS-CoV-2 infection in military personnel? Review of the evidence.

For most individuals residing in Northwestern Europe, maintaining replete vitamin D status throughout the year is unlikely without vitamin D supplementation and deficiency remains common. Military studies have investigated the association with vitamin D status, and subsequent supplementation, with the risk of stress fractures particularly during recruit training. The expression of nuclear vitamin D receptors and vitamin D metabolic enzymes in immune cells additionally provides a rationale for the potential role of vitamin D in maintaining immune homeostasis. One particular area of interest has been in the prevention of acute respiratory tract infections (ARTIs). The aims of this review were to consider the evidence of vitamin D supplementation in military populations in the prevention of ARTIs, including SARS-CoV-2 infection and consequent COVID-19 illness. The occupational/organisational importance of reducing transmission of SARS-CoV-2, especially where infected young adults may be asymptomatic, presymptomatic or paucisymptomatic, is also discussed.

Experience from the selection and nutritional preparation for Expedition ICE MAIDEN: the first successful all-female unassisted Antarctic traverse.

INTRODUCTION: Expedition ICE MAIDEN (Ex IM) was the first all-female unsupported crossing of Antarctica. We describe the prerequisite selection and training, comparing those who formed the final team with other participants, and discuss how the expedition diet was established. METHODS: All women serving in the British Army were invited to participate. Following initial assessments, successful women completed three training/selection ski expeditions. Between expeditions 1 and 2, participants completed 6 months rigorous UK-based training. Weight was measured before and after the 6 months UK-based training, expeditions 2 and 3, and body composition by skinfold before and after expedition 2. Participant feedback, body composition and weight changes were applied to modify the expedition diet and provide weight gain targets prior to Ex IM. RESULTS: Following 250 applications, 50 women were assessed and 22, 12 and seven women attended training expeditions 1, 2 and 3, respectively. The final team of six women lost more weight than other participants during UK-based training (mean (SD) change -1.3 (1.5) kg vs -0.5 (1.6) kg, respectively, p=0.046) and during training expedition 2 (-2.8 (0.8) kg vs -1.7 (0.4) kg, respectively, p=0.048), when they also gained more lean mass (+2.1 (0.8) kg vs +0.4 (0.7) kg, respectively, p=0.004). The Ex IM diet provided 5000 kCal/day, comprising approximately 45% carbohydrate, 45% fat and 10% protein. Median (range) weight change between expedition 3 and Ex IM was +8.7 (-1.9 to +14.3) kg. CONCLUSIONS: The selected Ex IM team demonstrated favourable training-associated body composition changes. Training-associated weight loss informed the expeditionary diet design.

Positive adaptation of HPA axis function in women during 44 weeks of infantry-based military training.

BACKGROUND: Basic military training (BMT) is a useful model of prolonged exposure to multiple stressors. 8-12 week BMT is associated with perturbations in the hypothalamic-pituitary-adrenal (HPA) axis which could predispose recruits to injury and psychological strain. However, characterisations of HPA axis adaptations during BMT have not been comprehensive and most studies included few if any women. METHODS: We studied women undertaking an arduous, 44-week BMT programme in the UK. Anxiety, depression and resilience questionnaires, average hair cortisol concentration (HCC), morning and evening saliva cortisol and morning plasma cortisol were assessed at regular intervals throughout. A 1-h dynamic cortisol response to 1 µg adrenocorticotrophic hormone-1-24 was performed during weeks 1 and 29. RESULTS: Fifty-three women (aged 24 ± 2.5 years) completed the study. Questionnaires demonstrated increased depression and reduced resilience during training (F 6.93 and F 7.24, respectively, both p < 0.001). HCC increased from 3 months before training to the final 3 months of training (median (IQR) 9.63 (5.38, 16.26) versus 11.56 (6.2, 22.45) pg/mg, p = 0.003). Morning saliva cortisol increased during the first 7 weeks of training (0.44 ± 0.23 versus 0.59 ± 0.24 µg/dl p < 0.001) and decreased thereafter, with no difference between the first and final weeks (0.44 ± 0.23 versus 0.38 ± 0.21 µg/dl, p = 0.2). Evening saliva cortisol did not change. Fasting cortisol decreased during training (beginning, mid and end-training concentrations: 701 ± 134, 671 ± 158 and 561 ± 177 nmol/l, respectively, p < 0.001). Afternoon basal cortisol increased during training while there was a trend towards increased peak stimulated cortisol (177 ± 92 versus 259 ± 13 nmol/l, p = 0.003, and 589 ± 164 versus 656 ± 135, p = 0.058, respectively). DISCUSSION: These results suggest a normal stress response in early training was followed quickly by habituation, despite psychological and physical stress evidenced by questionnaire scores and HCC, respectively. There was no evidence of HPA axis maladaptation. These observations are reassuring for women undertaking arduous employment.

Identification of a RELIK orthologue in the European hare (Lepus europaeus) reveals a minimum age of 12 million years for the lagomorph lentiviruses.

The retroviral genus Lentivirus comprises retroviruses characterised from five mammalian orders. Lentiviruses typically undergo rapid rates of evolution, a feature that has allowed recent evolutionary relationships to be elucidated, but has also obscured their distant evolutionary past. However, the slowdown in the rate of evolution associated with genome invasion, as has occurred in the European rabbit, enables longer-term lentiviral evolutionary history to be inferred. Here we report the identification of orthologous RELIK proviruses in the European hare, demonstrating a minimum age of 12 million years for the lagomorph lentiviruses. This finding indicates an association between lentiviruses and their hosts covering much of the evolutionary history of the lagomorphs, and taking place within species with a worldwide distribution.

Calibration of a subcutaneous amperometric glucose sensor. Part 1. Effect of measurement uncertainties on the determination of sensor sensitivity and background current.

The calibration of a continuous glucose monitoring system, i.e. the transformation of the signal I(t) generated by the glucose sensor at time (t) into an estimation of glucose concentration G(t), represents a key issue. The two-point calibration procedure consists of the determination of a sensor sensitivity S and of a background current I(o) by plotting two values of the sensor signal versus the concomitant blood glucose concentrations. The estimation of G(t) is subsequently given by G(t) = (I(t)-I(o))/S. A glucose sensor was implanted in the subcutaneous tissue of nine type 1 diabetic patients during 3 (n = 2) and 7 days (n = 7). For each individual trial, S and I(o) were determined by taking into account the values of two sets of sensor output and blood glucose concentration distant by at least 1 h, the procedure being repeated for each consecutive set of values. S and I(o) were found to be negatively correlated, the value of I(o) being sometimes negative. Theoretical analysis demonstrates that this phenomenon can be explained by the effect of measurement uncertainties on the determination of capillary glucose concentration and of sensor output.

Calibration of a subcutaneous amperometric glucose sensor implanted for 7 days in diabetic patients. Part 2. Superiority of the one-point calibration method.

UNLABELLED: Calibration, i.e. the transformation in real time of the signal I(t) generated by the glucose sensor at time t into an estimation of glucose concentration G(t), represents a key issue for the development of a continuous glucose monitoring system. OBJECTIVE: To compare two calibration procedures. In the one-point calibration, which assumes that I(o) is negligible, S is simply determined as the ratio I/G, and G(t) = I(t)/S. The two-point calibration consists in the determination of a sensor sensitivity S and of a background current I(o) by plotting two values of the sensor signal versus the concomitant blood glucose concentrations. The subsequent estimation of G(t) is given by G(t) = (I(t)-I(o))/S. RESEARCH DESIGN AND METHODS: A glucose sensor was implanted in the abdominal subcutaneous tissue of nine type 1 diabetic patients during 3 (n = 2) and 7 days (n = 7). The one-point calibration was performed a posteriori either once per day before breakfast, or twice per day before breakfast and dinner, or three times per day before each meal. The two-point calibration was performed each morning during breakfast. RESULTS: The percentages of points present in zones A and B of the Clarke Error Grid were significantly higher when the system was calibrated using the one-point calibration. Use of two one-point calibrations per day before meals was virtually as accurate as three one-point calibrations. CONCLUSION: This study demonstrates the feasibility of a simple method for calibrating a continuous glucose monitoring system.

Liberalized screening for blunt carotid and vertebral artery injuries is justified.

BACKGROUND: Current literature suggests that blunt carotid injuries (BCIs) and vertebral artery injuries (BVIs) are more common than once appreciated. Screening criteria have been suggested, but only one previous study has attempted to identify factors that predict the presence of BCI/BVI. This current study was conducted for two reasons. First, we wanted to determine the incidence of BCI/BVI in our institution. Second, we wanted to determine the incidence of abnormal four-vessel cerebral angiograms ordered for injuries and signs believed to be associated with BCI/BVI and thus to determine whether the screening protocol developed was appropriate. METHODS: From August 1998, we used liberalized screening criteria for patients who were prospectively identified and suspected to be at high risk for BCI/BVI if any of the following were present: anisocoria, unexplained mono-/hemiparesis, unexplained neurologic exam, basilar skull fracture through or near the carotid canal, fracture through the foramen transversarium, cerebrovascular accident or transient ischemic attack, massive epistaxis, severe flexion or extension cervical spine fracture, massive facial fractures, or neck hematoma. Four-vessel cerebral angiograms were used for screening for BCI/BVI. RESULTS: Over the 18-month study period, 48 patients were angiographically screened, with 21 patients (44%) being identified as having a total of 19 BCIs and 10 BVIs. Nine patients had unilateral carotid artery injuries and three patients had bilateral carotid artery injuries. Vertebral artery injuries were unilateral in six patients. One patient had bilateral carotid artery injuries and a unilateral vertebral artery injury. One patient had a unilateral carotid artery injury and a unilateral vertebral artery injury, and one patient had a unilateral carotid artery injury and bilateral vertebral artery injuries. During the same study period, 2,331 trauma patients were admitted, with 1,941 (83%) secondary to blunt trauma. The overall incidence of BCI/BVI was 1.1%. The frequency of abnormal angiograms ordered for cerebrovascular accident or transient ischemic attack, massive epistaxis, or severe cervical spine fractures was 100%. The frequency of abnormal angiograms ordered for the other indications was as follows: fracture through foramen transversarium, 60%; unexplained mono- or hemiparesis, 44%; basilar skull fracture, 42%; unexplained neurologic examination, 38%; anisocoria, 33%; and severe facial fractures, 0%. CONCLUSION: The liberalized screening criteria used in this study were appropriate to identify patients with BCI/BVI. This study suggests BCI/BVI to be more common than previously believed and justifies that screening should be liberalized.

Spontaneous renal artery dissection in a healthy man.

We have presented a unique case of isolated renal artery dissection in an otherwise healthy young man, whose diagnosis was demonstrated by renal angiography. He was anticoagulated with warfarin for one year with resolution of the false channel in his renal artery as demonstrated by magnetic resonance angiography. Duplex ultrasonography of his renal artery was important in monitoring his renal artery flow velocities.

FISH 3: a microworld for studying social dilemmas and resource management.

A Java-based microworld environment for studying resource management is described. FISH 3 may be used in research or the classroom to investigate commons dilemmas and resource dilemmas. The program uses ocean fishing as its metaphor; participants ("fishers") experience the metaphor through both graphics ("fish" may be seen in an ocean) and text (e.g., resource replenishment is translated as "spawning"). In either stand-alone or networked modes, either with all human fishers or a mixture of human and computer fishers, 15 parameters such as the number of resource units (fish), participants (fishers), and trials (seasons), payoff values, the rate and period of resource regeneration (spawning), harvesting greed by computer fishers, awareness of other harvesters' actions, uncertainty in the amount of the resource, operating costs, and whether the resource is visible to harvesters may be varied.

Contributions of suppression and excitation to simultaneous masking: effects of signal frequency and masker-signal frequency relation.

This study investigated the contributions of suppression and excitation to simultaneous masking for a range of masker frequencies both below and above three different signal frequencies (750, 2000, and 4850 Hz). A two-stage experiment was employed. In stage I, the level of each off-frequency simultaneous masker necessary to mask a signal at 10 or 30 dB sensation level was determined. In stage II, three different forward-masking conditions were tested: (1) an on-frequency condition, in which the signals in stage I were used to mask probes of the same frequency; (2) an off-frequency condition, in which the off-frequency maskers (at the levels determined in stage I) were used to mask the probes; and (3) a combined condition, in which the on- and off-frequency maskers were combined to mask the probes. If the off-frequency maskers simultaneously masked the signal via spread of excitation in stage I, then the off-frequency and combined maskers should produce considerable forward masking in stage II. If, on the other hand, they masked via suppression, they should produce little or no forward masking. The contribution of suppression was found to increase with increasing signal frequency; it was absent at 750 Hz, but dominant at 4850 Hz. These results have implications for excitation pattern analyses and are consistent with stronger nonlinear processing at high rather than at low frequencies.

Interstitial glucose concentration and glycemia: implications for continuous subcutaneous glucose monitoring.

The changes in plasma glucose concentration and in interstitial glucose concentration, determined with a miniaturized subcutaneous glucose sensor, were investigated in anesthetized nondiabetic rats. Interstitial glucose was estimated through two different calibration procedures. First, after a glucose load, the magnitude of the increase in interstitial glucose, estimated through a one-point calibration procedure, was 70% of that in plasma glucose. We propose that this is due to the effect of endogenous insulin on peripheral glucose uptake. Second, during the spontaneous secondary decrease in plasma glucose after the glucose load, interstitial glucose decreased faster than plasma glucose, which may also be due to the effect of insulin on peripheral glucose uptake. Third, during insulin-induced hypoglycemia, the decrease in interstitial glucose was less marked than that of plasma glucose, suggesting that hypoglycemia suppressed transfer of glucose into the interstitial tissue; subsequently, interstitial glucose remained lower than plasma glucose during its return to basal value, suggesting that the stimulatory effect of insulin on peripheral glucose uptake was protracted. If these observations obtained in rats are relevant to human physiology, such discrepancies between plasma and interstitial glucose concentration may have major implications for the use of a subcutaneous glucose sensor in continuous blood glucose monitoring in diabetic patients.

Gender differences in subjective distress attributable to anticipation of combat among U.S. Army soldiers deployed to the Persian Gulf during Operation Desert Storm.

This study compares perceptions of stress, cohesion, and psychological well-being among 856 male soldiers and 169 female soldiers from combat support and combat service support units deployed to the Persian Gulf during Operation Desert Storm. Three different types of stressors were measured: anticipation of combat, operational stress, and personal stress. Female soldiers scored higher than male soldiers on all three measures of stress but scored lower than males on horizontal and vertical cohesion. In a stepwise discriminant function analysis, anticipation of combat was the most significant discriminator between the genders, followed by horizontal cohesion. Anticipation of combat was a significant predictor of increased psychological symptoms for both genders, but it had a greater effect on the psychological symptoms of female soldiers compared with male soldiers.