Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Making allyship visible: evaluation of a faculty development DEI curriculum

Undergraduate medical learners from historically marginalized groups face significant barriers, which was made concrete at our institution when a student presented her research indicating that Black students felt unsure about which faculty members to approach. To better support our students, we used Kern's model for curriculum development and a critical pedagogy approach to create a Faculty Allyship Curriculum (FAC). A total of 790 individuals attended 90 workshops across 16 months and 20 individuals have completed the FAC. A majority of participants reported they felt at least moderately confident in their ability to teach learners who are underrepresented in medicine, mentor learners who are different than they are, and teach allyship topics. An informal content analysis of open-ended responses indicated changes in awareness, attitude, insight, and use of language and being more likely to display advocacy. For others considering creating a similar program, partnering with an existing program allows for rapid implementation and reach to a wide audience. We also recommend: beginning with a coalition of willing learners to quickly build community and culture change; ensuring that the curriculum supports ongoing personal commitment and change for the learners; and supporting facilitators in modeling imperfection and upstanding, 'calling in' rather than 'calling out' learners.

Perspective: Council for Responsible Nutrition Science in Session. Optimizing Health with Nutrition-Opportunities, Gaps, and the Future

Achieving optimal health is an aspirational goal for the population, yet the definition of health remains unclear. The role of nutrition in health has evolved beyond correcting malnutrition and specific deficiencies and has begun to focus more on achieving and maintaining 'optimal' health through nutrition. As such, the Council for Responsible Nutrition held its October 2022 Science in Session conference to advance this concept. Here, we summarize and discuss the findings of their Optimizing Health through Nutrition - Opportunities and Challenges workshop, including several gaps that need to be addressed to advance progress in the field. Defining and evaluating various indices of optimal health will require overcoming these key gaps. For example, there is a strong need to develop better biomarkers of nutrient status, including more accurate markers of food intake, as well as biomarkers of optimal health that account for maintaining resilience-the ability to recover from or respond to stressors without loss to physical and cognitive performance. In addition, there is a need to identify factors that drive individualized responses to nutrition, including genotype, metabotypes, and the gut microbiome, and to realize the opportunity of precision nutrition for optimal health. This review outlines hallmarks of resilience, provides current examples of nutritional factors to optimize cognitive and performance resilience, and gives an overview of various genetic, metabolic, and microbiome determinants of individualized responses.

Exploring Influences of Eating Behaviors Among Emerging Adults in the Military

OBJECTIVE

Identify factors influencing eating behaviors among emerging adults in the military.

DESIGN

Focused ethnography using interviews, observations, and artifacts for data.

SETTING

Three US Naval installations.

PARTICIPANTS

Thirty-two active-duty Sailors aged 18-25 years.

ANALYSIS

Qualitative data were organized in NVivo and analyzed sequentially to categorize culturally relevant domains and themes using a social ecological model (SEM). Descriptive statistics were used to describe questionnaire data in SPSS (version 27.0, IBM, 2020).

RESULTS

Leaders encouraged healthy eating through policies and messages, but cultural contradictions and environmental barriers undermined Sailors' efforts to eat healthily. Stress and resource constraints (intrapersonal), peer pressure (social), unhealthy food environments and lack of access to food preparation (environmental), and eating on the go because of mission-first norms (cultural) promoted unhealthy eating behaviors. Nutrition and culinary literacy (intrapersonal); peer support and leadership engagement (social); access to healthy, convenient, and low-cost foods (environmental); and indoctrination to healthy eating during recruit training (cultural) positively influenced eating behaviors.

CONCLUSION AND IMPLICATIONS

The eating behaviors of service members are influenced by many modifiable factors. Targeted education, leadership engagement, and policies that make nutritious foods easily accessible, appealing, and preferred are needed.

Hydration: Tactical and Practical Strategies

Full-spectrum Human Performance Optimization (HPO) is essential for Special Operations Forces (SOF). Adequate hydration is essential to all aspects of performance (physical and cognitive) and recovery. Water losses occur as a result of physical activity and can increase further depending on clothing and environmental conditions. Without intentional and appropriate strategic hydration planning, Operators are at increased risk for degradation in performance and exertional heat illness. The purpose of this article is to highlight current best practices for maintaining hydration before, during, and after activity, while considering various environmental conditions. Effective leadership and planning are necessary for preparing Operators for successful military operations.

Role of nutrition in human performance in military populations

The role of nutrition and performance is well established. Service members' physical and cognitive performance, sleep and mood are impacted by nutritional choices. Although many eating patterns have emerged, consensus among experts recommend a dietary pattern focused on predominantly whole plant-based foods. Adequate intakes of fruits, vegetables, whole grains, beans, legumes, nuts and seeds should be prioritised. Implementation of strategic and intentional fuelling strategies around times of activity maintain adequate energy stores, enhance recovery and protect against training injuries. Carbohydrates are prioritised before, during and after activity or a mission, although the type and amount will vary based on duration and intensity of activity. Protein is generally the focus after activity or a mission and may be included before activity depending on individual tolerance. There are no specific recommendations for fat consumption before, during and after exercise that will improve performance. That said, Service members generally tolerate low-fat meals/snacks prior to exercise, limit fat intake during exercise, may include fat as part of the post exercise meal/snack, and generally consume most fat during the maintenance and growth phase. Careful consideration and planning for food and fluid requirements should be made when Service members are exposed to heat, cold and/or altitude. Operational rations are formulated to meet the nutritional needs of all Service members across a variety of diverse climates, environments and altitudes. Service members may use dietary supplements to improve their performance and need to be aware of available resources to help them make informed decisions.

Differential effect of dementia etiology on cortical stiffness as assessed by MR elastography

BACKGROUND

Aging and dementia involve the disruption of brain molecular pathways leading to the alterations in tissue composition and gross morphology of the brain. Phenotypic and biomarker overlap between various etiologies of dementia supports a need for new modes of information to more accurately distinguish these disorders. Brain mechanical properties, which can be measured noninvasively by MR elastography, represent one understudied feature that are sensitive to neurodegenerative processes. In this study, we used two stiffness estimation schemes to test the hypothesis that different etiologies of dementia are associated with unique patterns of mechanical alterations across the cerebral cortex.

METHODS

MR elastography data were acquired for six clinical groups including amyloid-negative cognitively unimpaired (CU), amyloid-positive cognitively unimpaired (A + CU), amyloid-positive participants with mild cognitive impairment (A + MCI), amyloid-positive participants with Alzheimer's clinical syndrome (A + ACS), dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD). Stiffness maps were computed using two neural network inversions with the objective to at least partially separate the parenchyma-specific and morphological effects of neurodegeneration on mechanical property estimates. A tissue-confined inversion algorithm was designed to obtain the best estimate of stiffness in the brain parenchyma itself, while a regionally-aware inversion algorithm was used to measure the tissue stiffness along with the surroundings. Mean stiffness of 15 bilateral gray matter cortical regions were considered for statistical analysis. First, we tested the hypothesis that cortical stiffness changes in the aging brain. Next, we tested the overall study hypothesis by first comparing stiffness in each clinical group to the CU group, and then comparing the clinical groups against one another. Finally, we assessed the spatial and statistical overlap between atrophy and stiffness changes for both inversions.

RESULTS

Cortical brain regions become softer with age for both inversions with larger effects observed using regionally-aware stiffness. Stiffness decreases in the range 0.010-0.027 kPa per year were observed. Pairwise comparisons of each clinical group with cognitively unimpaired participants demonstrated 5 statistically significant differences in stiffness for tissue-confined measurements and 19 statistically different stiffness changes for the regionally-aware stiffness measurements. Pairwise comparisons between clinical groups further demonstrated unique patterns of stiffness differences. Analysis of the atrophy-versus-stiffness relationship showed that regionally-aware stiffness measurements exhibit higher sensitivity to neurodegeneration with findings that are not fully explained by partial volume effects or atrophy.

CONCLUSIONS

Both tissue-confined and regionally-aware stiffness estimates exhibited unique and complementary stiffness differences in various etiologies of dementia. Our results suggest that mechanical alterations measured by MRE reflect both tissue-specific differences as well as environmental effects. Multi-inversion schemes in MRE may provide new insights into the relationships between neuropathology and brain biomechanics.

Iron deficiency and high-intensity running interval training do not impact femoral or tibial bone in young female rats

In the USA, as many as 20 % of recruits sustain stress fractures during basic training. In addition, approximately one-third of female recruits develop Fe deficiency upon completion of training. Fe is a cofactor in bone collagen formation and vitamin D activation, thus we hypothesised Fe deficiency may be contributing to altered bone microarchitecture and mechanics during 12-weeks of increased mechanical loading. Three-week old female Sprague Dawley rats were assigned to one of four groups: Fe-adequate sedentary, Fe-deficient sedentary, Fe-adequate exercise and Fe-deficient exercise. Exercise consisted of high-intensity treadmill running (54 min 3×/week). After 12-weeks, serum bone turnover markers, femoral geometry and microarchitecture, mechanical properties and fracture toughness and tibiae mineral composition and morphometry were measured. Fe deficiency increased the bone resorption markers C-terminal telopeptide type I collagen and tartate-resistant acid phosphatase 5b (TRAcP 5b). In exercised rats, Fe deficiency further increased bone TRAcP 5b, while in Fe-adequate rats, exercise increased the bone formation marker procollagen type I N-terminal propeptide. In the femur, exercise increased cortical thickness and maximum load. In the tibia, Fe deficiency increased the rate of bone formation, mineral apposition and Zn content. These data show that the femur and tibia structure and mechanical properties are not negatively impacted by Fe deficiency despite a decrease in tibiae Fe content and increase in serum bone resorption markers during 12-weeks of high-intensity running in young growing female rats.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

Impact of material homogeneity assumption on cortical stiffness estimates by MR elastography

PURPOSE

Inversion algorithms used to convert acquired MR elastography wave data into material property estimates often assume that the underlying materials are locally homogeneous. Here we evaluate the impact of that assumption on stiffness estimates in gray-matter regions of interest in brain MR elastography.

METHODS

We describe an updated neural network inversion framework using finite-difference model-derived data to train convolutional neural network inversion algorithms. Neural network inversions trained on homogeneous simulations (homogeneous learned inversions [HLIs]) or inhomogeneous simulations (inhomogeneous learned inversions [ILIs]) are generated with a variety of kernel sizes. These inversions are evaluated in a brain MR elastography simulation experiment and in vivo in a test-retest repeatability experiment including 10 healthy volunteers.

RESULTS

In simulation and in vivo, HLI and ILI with small kernels produce similar results. As kernel size increases, the assumption of homogeneity has a larger effect, and HLI and ILI stiffness estimates show larger differences. At each inversion's optimal kernel size in simulation (7 × 7 × 7 for HLI, 11 × 11 × 11 for ILI), ILI is more sensitive to true changes in stiffness in gray-matter regions of interest in simulation. In vivo, there is no difference in the region-level repeatability of stiffness estimates between the inversions, although ILI appears to better maintain the stiffness map structure as kernel size increases, while decreasing the spatial variance in stiffness estimates.

CONCLUSIONS

This study suggests that inhomogeneous inversions provide small but significant benefits even when large stiffness gradients are absent.

Intermittent Fasting: Can It Help Optimize Human Performance?

Nutritional fitness is a key goal of every Special Operations Forces (SOF) Operator, and nutrition is one way of potentially gaining a necessary edge. Although fad diets are popular among SOF Operators, many have no evidence with regard to military-specific tasks. One fad diet-intermittent fasting (IF)-is clearly the rage across the United States (US) and popular as a dietary pattern. Most fad diets are studied in the context of various chronic diseases, in particular, cardiovascular disease, diabetes, and obesity, and there are no data on the benefits among SOF or any military population. Thus, evidence demonstrating improvements in performance is typically lacking. Despite no clear evidence, many still devote their lives to popular fad diets. We address whether IF confers performance improvements in SOF by first discussing the concepts of metabolic flexibility and metabolic shifting, then describing IF and its subtypes, after which we summarize the literature with regard to cardiovascular disease and obesity. We close with how IF impacts performance and discuss who should use consider using IF as a dietary pattern.

Artificial neural networks for magnetic resonance elastography stiffness estimation in inhomogeneous materials

PURPOSE

To test the hypothesis that removing the assumption of material homogeneity will improve the spatial accuracy of stiffness estimates made by Magnetic Resonance Elastography (MRE).

METHODS

An artificial neural network was trained using synthetic wave data computed using a coupled harmonic oscillator model. Material properties were allowed to vary in a piecewise smooth pattern. This neural network inversion (Inhomogeneous Learned Inversion (ILI)) was compared against a previous homogeneous neural network inversion (Homogeneous Learned Inversion (HLI)) and conventional direct inversion (DI) in simulation, phantom, and in-vivo experiments.

RESULTS

In simulation experiments, ILI was more accurate than HLI and DI in predicting the stiffness of an inclusion in noise-free, low-noise, and high-noise data. In the phantom experiment, ILI delineated inclusions ≤ 2.25 cm in diameter more clearly than HLI and DI, and provided a higher contrast-to-noise ratio for all inclusions. In a series of stiff brain tumors, ILI shows sharper stiffness transitions at the edges of tumors than the other inversions evaluated.

CONCLUSION

ILI is an artificial neural network based framework for MRE inversion that does not assume homogeneity in material stiffness. Preliminary results suggest that it provides more accurate stiffness estimates and better contrast in small inclusions and at large stiffness gradients than existing algorithms that assume local homogeneity. These results support the need for continued exploration of learning-based approaches to MRE inversion, particularly for applications where high resolution is required.

Effects of vitamin D supplementation on salivary immune responses during Marine Corps basic training

Vitamin D's role in regulating immune responses may increase during periods of elevated psychological and physiological stress. Due to the high demands placed on US Marine Corps recruits undergoing 12 weeks of basic military training, we hypothesized that vitamin D status would be related to markers of innate mucosal immunity, and daily vitamin D supplementation would augment immune responses during training. Males (n = 75) and females (n = 74) entering recruit basic training during the summer and winter volunteered to participate in a randomized, double-blind, placebo-controlled study. Subjects received either 1000 IU vitamin D₃  + 2000 mg calcium/d (n = 73) or placebo (n = 76) for 12 weeks. Saliva samples were collected pre-training, during (weeks 4 and 8), and post-training (week 12) in order to determine salivary SIgA and cathelicidin (indices of mucosal immunity) and α-amylase (indicator of stress). Initial (baseline) and post-training serum 25(OH)D levels were measured. Results were as follows: serum 25(OH)D levels were 37% higher in recruits entering training in summer compared with winter. A positive relationship was observed between baseline 25(OH)D levels and SIgA secretion rates (-SR). When stress levels were high during summer training, baseline 25(OH)D levels contributed to an increase in salivary secretory immunoglobulin A secretion rates (SIgA-SR) and cathelicidin-SR, the latter only in males. Vitamin D supplementation contributed to the changes in SIgA-SR and cathelicidin-SR, specifically SIgA-SR was higher in the treatment group. These data highlight the importance of vitamin D and mucosal immune responses during arduous basic military training when stress levels are increased.

Calcium and vitamin D supplementation and bone health in Marine recruits: Effect of season

Stress fractures are common overuse injuries caused by repetitive bone loading. These fractures are of particular concern for military recruits and athletes resulting in attrition in up to 60% of recruits that sustain a fracture. Army and Navy recruits supplemented with daily calcium and vitamin D (Ca + D) demonstrated improved bone strength and reduced stress fractures. The aim of the current study was to evaluate whether Ca + D supplementation improves measures of bone health in recruits undergoing United States Marine Corps initial military training (IMT), and whether the effect of supplementation on indices of bone health varied by season. One-hundred ninety-seven Marine recruits (n = 107 males, n = 90 females, mean age = 18.9 ± 1.6 y) were randomized to receive either Ca + D fortified snack bars (2000 mg Ca and 1000 IU vitamin D per day) or placebo divided into twice daily doses during 12 weeks of IMT. Anthropometrics, fasted blood samples, and peripheral quantitative computed tomography (pQCT) scans of the tibial metaphysis and diaphysis were collected upon entrance to- and post-training (12 weeks later). Half of the volunteers entered training in July and the other half started in February. Time-by-group interactions were observed for vitamin D status (25OHD) and the bone turnover markers, BAP, TRAP and OCN. 25OHD increased and BAP, TRAP and OCN all decreased in the Ca + D group (p < .05). Training increased distal tibia volumetric BMD (+1.9 ± 2.8%), BMC (+2.0 ± 3.1%), and bone strength index (BSI; +4.0 ± 4.0%) and diaphyseal BMC (+1.0 ± 2.2%) and polar stress strain index (SSIp; +0.7 ± 2.1%) independent of Ca + D supplementation (p < .05 for all). When analyzed by season, change in BSI was greater in the Ca + D group as compared to placebo in the summer iteration only (T*G; p < .05). No other effects of supplementation on bone tissue were observed. When categorized by tertile of percent change in BSI, recruits demonstrating the greatest changes in BSI and 25OHD entered training with the lowest levels of 25OHD (p < .05). Over all, these results suggest that Ca + D supplementation reduced some markers of bone formation and resorption and the decline in 25OHD over training in volunteers that started training in the summer was prevented by supplementation. Baseline 25OHD and trajectory may impact bone responses to IMT, but little effect of Ca + D supplementation was observed at the investigated doses.

Usefulness of a Risk Assessment Tool to Risk Stratify Dietary Supplements

BACKGROUND

The use of dietary supplements (DSs) is widespread in the military. Service members use DS for any number of reasons, to include supporting general health, increasing energy levels, enhancing performance, and promoting gains in strength. However, some readily available DS products are potentially unsafe. Therefore, the purpose of this study is to assess the ability of military medical students to use the Operation Supplement Safety DS risk assessment tool. The Operation Supplement Safety risk assessment tool was developed to assist Service members in making decisions about safe DS use.

METHODS

Fourth-year medical students used an online assessment tool to risk stratify and evaluate the safety of 12 predesignated DS. The assessment tool consists of seven polar questions (yes/no), with an answer of "yes" given a score of 1 and an answer of "no" given a score of 0. Students recorded responses to each of the seven questions for each of the 12 DSs. The tool then generated a total score for each DS, which was compared to the previously identified correct total score. Students' scores for each individual yes/no question and final conclusion about DS safety were also assessed.

FINDINGS

Forty responses for the 12 DSs were examined. Five supplements were expected to receive a score of ≥4, suggesting they were likely safe. The average scores (± standard deviation [SD]) for each DS vs. the correct safety score were fish oil (5.9 ± 1.4 vs. 7.0), iron (4.2 ± 1.4 vs. 4.0), melatonin (4.9 ± 0.8 vs. 5.0), multivitamin/mineral (3.8 ± 1.1 vs. 4.0), multivitamin/mineral for men (4.0 ± 1.0 vs. 5.0), performance-enhancing supplement A (1.5 ± 1.1 vs. 2.0), performance-enhancing supplement B (2.0 ± 1.0 vs. 3.0), performance-enhancing supplement C (0.6 ± 0.5 vs. 1.0), performance-enhancing supplement D (1.8 ± 1.0 vs. 3.0), performance-enhancing supplement E (1.5 ± 1.3 vs. 1.0), sexual enhancement supplement (1.3 ± 0.7 vs. 1.0), and weight loss supplement (1.1 ± 1.1 vs. 1.0).

DISCUSSION/IMPACT/RECOMMENDATIONS

The DS risk assessment tool provides consumers a quick way to screen DS for safety and can help consumers make more informed decisions when purchasing DS. Scores had minimal intersubject variability and were comparable to expected risk stratification. Our results suggest the assessment tool may be appropriate for medical students to use when investigating the safety of DS. We recommend additional research to verify whether the findings from this study would be similar for other potential users, as well as assess other psychometric properties.

Ketones and Human Performance

Everyone is seeking nutritional strategies that might benefit performance. One approach receiving much attention is ketones, or ketosis. Ketones are very simple compounds made of hydrogen, carbon, and oxygen, and ketosis is a metabolic state whereby the body uses predominantly ketones. Ketosis can be achieved by fasting for longer than 72 hours or by following a very lowcarbohydrate, high-fat diet (ketogenic diet) for several days to weeks. Alternatively, ketone supplements purportedly induce ketosis rapidly and do not require strict adherence to any specific type of diet; however, much of the touted benefits are anecdotal. A potential role for ketosis as a performance enhancer was first introduced in 1983 with the idea that chronic ketosis without caloric restriction could preserve submaximal exercise capability by sparing glycogen or conserving the limited carbohydrate stores. Few human studies on the effects of a ketogenic diet on performance have yielded positive results, and most studies have yielded equivocal or null results, and a few negative results. Many questions about ketones relevant to Special Operations Forces (SOF) remain unanswered. At present, a ketogenic diet and/or a ketone supplement do not appear confer performance benefits for SOF. Instead, Operators should engage with their unit dietitian to develop individualized nutritional strategies based on unique mission requirements. The authors review the concept of a ketogenic diet, describe some potential benefits and risks of ketosis, review the performance literature and how to measure ketone status, and then summarize the landscape in 2017.

A pilot study of nocturnal temporalis muscle activity in TMD diagnostic groups of women

Temporomandibular disorder (TMD) incidences are believed to be related to parafunctional behaviours like teeth clenching. This pilot study aimed to (i) develop an automated clench-detection algorithm, and (ii) apply the algorithm to test for differences in nocturnal clenching in women with and without TMD. Subjects gave informed consent to participate. Adult women were categorised using Diagnostic Criteria for TMD according to presence/absence (+/-) of both TM joint disc placement (DD) and chronic pain (P) into two groups (+DD+P, -DD-P) with 12 subjects each. Surface temporalis electromyography was recorded during oral tasks performed by subjects at two laboratory sessions. The data were used to characterise muscle activity per N of bite force (μV/N) for each subject, develop the clench-detection algorithm and test its accuracy. Ambulatory surface temporalis electromyography was self-recorded by each subject over three nights and analysed using the algorithm and bite force (N) versus muscle activity μV/N calibrations. Bonferroni-adjusted homoscedastic t-tests assessed for significant between-group differences in clenching (P < 0·05). Sensitivity, specificity and accuracy of algorithm-detected laboratory clenches were all ≥96%. During self-recordings 95% of clenches had durations of <4 s and peak forces of <10 N in both groups. Mean clench durations were significantly longer (P = 0·042) in +DD+P (1·9 ± 0·8 s) than -DD-P subjects (1·4 ± 0·4 s). Mean temporalis duty factors (%clench time/total recording time) were significantly larger (P = 0·041) in +DD+P (0·47 ± 0·34%) than -DD-P (0·26 ±0·22%) subjects. Nocturnal temporalis muscle activities detected by a validated algorithm were longer per clench and recording time in +DD+P compared to -DD-P women.

A Novel Eigenvector-based Method to Detect Mild Alzheimer's Disease Using Event-Related Potentials

Event-related potentials (ERPs) are a physiological measure of cognitive function that have shown diagnostic and prognostic utility in Alzheimer's disease (AD). In this study, we used a novel eigenvector-based technique to better understand brain electrophysiological differences between subjects with mild AD and healthy controls (HC). Using ERPs from 75 subjects with mild AD and 95 HC, we first calculated cognitive task eigenvectors within each subject from three conditions and then calculated second-order eigenvector components to compare the AD group to the HC group. A MANOVA of the three second-level components discriminated between AD and HC multivariately (Wilks' lambda=.4297, p<0.0001, R2 = .5703), and also on each of the three components univariately (all 3 p-values<0.0001). The eigenvector-based technique used in this study accurately discriminated between the mild AD group and HC. As such, this analysis method adds to our understanding of the differences in ERP signal between AD and HC, and could provide a sensitive biomarker for diagnosis and monitoring of AD progression.

Parent-reported distress in children under 3 years old during preventive medical and dental care

PURPOSE

This study examined factors related to young children's distress during preventive oral health visits. Additionally, associations between parent-reported child behaviour during the dental visit and during previous medical visits were tested.

METHODS

One hundred twenty-two children under 3 years of age enrolled in a government insurance programme for low-income children were seen for examination, prophylaxis, and fluoride application at a university-based dental clinic. Child distress was rated by parents on a numerical rating scale.

RESULTS

The average age of children enrolled was 23.5 ± 7.3 months. The majority (55.7 %) were judged to have little or no distress pre-examination. Mild or no distress during the examination was reported for 42.6 % of the children and severe distress was reported for 39.4 %. Intensity of distress during the examination was not associated with the child's age, gender, dental health, or previous experience with dental care. Distress was also unrelated to the caregiver's education level or own dental health. Intensity of distress was associated with the child's pre-dental examination distress and distress during prior medical examinations and injections.

CONCLUSIONS

Dental professionals can better anticipate child distress by assessing children before a dental examination and enquiring about previous medical experiences. Strategies to prepare parents and alleviate distress may help children cope with the preventive dental visit.

Oblique lateral radiographs and bitewings; estimation of organ doses in head and neck region with Monte Carlo calculations

OBJECTIVES

When bitewing radiographs are not possible (e.g. patients with special needs), oblique lateral radiographs may offer an alternative. The aims of this study were to assess the impact of horizontal projection angulation, focus-to-skin distance, exposure time and age of the patient on the equivalent radiation dose of several organs in the head and neck region by means of personal computer X-ray Monte Carlo (PCXMC) calculations and to assess the dose obtained from conventional bitewing radiographs.

METHODS

PCXMC v. 2.0 software (STUK(®), Helsinki, Finland) was used to estimate the equivalent radiation doses and the total effective dose. Three exposure times, five age categories, two focus-to-skin distances and eight horizontal geometric angulations were assumed. The organs involved were the thyroid gland, oesophagus, salivary glands, bone marrow, oral mucosa, skull, cervical spine and skin. A similar calculation was also performed for bitewings taken with a rectangular collimator. Results and conclusion Bitewings taken with rectangular collimation decrease the radiation burden of the patient to 50%, compared with circular collimation. In the oblique lateral radiographs, focus-to-skin distance, patient's age and beam collimation had a significant impact on the equivalent doses measured in this study. Exposure time had a significant impact on the equivalent doses of the salivary glands, oral mucosa, skull and skin. Horizontal angulations had a significant impact on the equivalent doses of the thyroid gland, bone marrow, oral mucosa, skull and cervical spine. The total effective radiation dose was significantly influenced by all parameters investigated in this study.

Differences in amounts and types of physical activity by obesity status in US adults

OBJECTIVES

To describe the physical activity patterns across levels of obesity among US adults.

METHODS

The frequency, intensity, and duration of physical activities were compared across obesity status in 7695 adults from NHANES, 1999-2006.

RESULTS

Significantly more normal-weight adults engaged in moderate- and vigorous- intensity activities and for a longer duration than did their overweight or obese counterparts. Lower intensity, longer duration walking contributed to nearly half of all moderate activity among obese subjects.

CONCLUSIONS

Significant differences exist in intensity, frequency, and duration of physical activity by weight status. This information suggests a targeted approach to current physical activity interventions be explored.

Racial Differences in Barriers to Blood Pressure Control in a Family Practice Setting

Objective: Hypertension prevalence in the African American community is greater than in all other ethnic groups. Cultural perceptions of health and disease introduce barriers to providing effective care. The purpose of this study was to identify racial differences in the perceived causes of hypertension, current behaviors performed to control blood pressure, and perceived barriers to preventing or treating hypertension. Methods: A self-administered survey of patients seen for medical care in a primary care network was conducted. The survey was developed to measure perceptions of hypertension etiology and treatments. Data from African American (n = 69) and Caucasian (n = 218) respondents were used to assess racial differences in perceptions of blood pressure control. Results: About half of respondents knew their current blood pressures. African American patients were significantly less likely to believe that hypertension was caused by a lack of exercise and obesity. Significantly more Caucasians were less likely to report cutting down on table salt and taking prescription medications for blood pressure control. Both African Americans and Caucasians believed that sodium reduction was the most easily changed behavior to control their blood pressure, while both groups identified weight loss as being the most difficult. Conclusion: Racial differences exist in the perceived causes and treatments of high blood pressure, indicating a need for further patient education. When treating and counseling patients, physicians and support staff members must be sensitive to racial diversity and strive to offer culturally relevant solutions, especially for behaviors perceived as most difficult to change.

Transcobalamin II receptor polymorphisms are associated with increased risk for neural tube defects

OBJECTIVE

Women who have low cobalamin (vitamin B(12)) levels are at increased risk for having children with neural tube defects (NTDs). The transcobalamin II receptor (TCblR) mediates uptake of cobalamin into cells. Inherited variants in the TCblR gene as NTD risk factors were evaluated.

METHODS

Case-control and family-based tests of association were used to screen common variation in TCblR as genetic risk factors for NTDs in a large Irish group. A confirmatory group of NTD triads was used to test positive findings.

RESULTS

2 tightly linked variants associated with NTDs in a recessive model were found: TCblR rs2336573 (G220R; p(corr)=0.0080, corrected for multiple hypothesis testing) and TCblR rs9426 (p(corr)=0.0279). These variants were also associated with NTDs in a family-based test before multiple test correction (log-linear analysis of a recessive model: rs2336573 (G220R; RR=6.59, p=0.0037) and rs9426 (RR=6.71, p=0.0035)). A copy number variant distal to TCblR and two previously unreported exonic insertion-deletion polymorphisms were described.

CONCLUSIONS

TCblR rs2336573 (G220R) and TCblR rs9426 represent a significant risk factor in NTD cases in the Irish population. The homozygous risk genotype was not detected in nearly 1000 controls, indicating that this NTD risk factor may be of low frequency and high penetrance. 9 other variants are in perfect linkage disequilibrium with the associated single nucleotide polymorphisms. Additional work is required to identify the disease-causing variant. Our data suggest that variation in TCblR plays a role in NTD risk and that these variants may modulate cobalamin metabolism.

Differences in the dietary intake habits by diabetes status for African American adults

BACKGROUND

African Americans (AA) are 1.8 times more likely to develop type 2 diabetes than non-Hispanic Whites. This increased diabetes risk has been linked to high rates of obesity and poor dietary habits; therefore, the purpose of this study is to identify how the nutrient intake profiles of AA adults differ by diabetes status.

METHODS

Dietary intakes of AA adults (aged > or =18 years; n=2,589) were examined from the 1999-2004 National Health and Nutrition Examination Survey. Individuals were stratified into three groups (normoglycemia, pre-diabetes, and diabetes) based on self-reported previous diagnosis, blood glucose and use of glucose-lowering medications. Dietary intakes were collected using 24-hour recalls; energy-adjusted nutrients intake were compared across diabetes status.

RESULTS

Risk for pre-diabetes was 4% higher for every one year increase in age, while the risk for diabetes was 7% higher. Those with diabetes consumed significantly less energy (P=.03) and significantly more energy-adjusted protein (P=.011) and dietary fiber (P<.001) compared to those with normal blood glucose. Mean consumption of carbohydrates were nearly two and a half times the estimated average requirement regardless of diabetes status. Individuals with diabetes had significantly higher intakes of several B-vitamins including thiamin, riboflavin, niacin, folate and B-6 compared to individuals who had normal blood glucose values.

CONCLUSION

This study identifies opportunities for improvement in the dietary habits of African Americans and supports the development of culturally-appropriate diabetes prevention and treatment strategies.

Heart rate variability responses to a psychologically challenging scuba dive

AIM

Given the controversy regarding cardiovascular responses and heart rate variability (HRV) in underwater conditions, the authors assessed the combined effect of psychological stress and scuba diving on cardiac autonomic modulation measured through HRV during and following a diving mission.

METHODS

Ten healthy adults (three females; seven males; Body Mass Index [BMI] 23.7 + or - 2.1; age 26.4 + or - 2.9) performed a 20-minute dive in a neutral buoyancy water tank (27 degrees C) at a depth of five meters. The dive scenario involved repairing components of a scientific instrument using a high fidelity task mock-up. Data for HRV (three from the time domain and three from the frequency domain) were obtained for 20 minutes prior to (PRE), during (DIVE), and for 20 minutes following (POST) the dive sortie.

RESULTS

Heart rate in DIVE was increased when compared to PRE and POST (74 + or - 10 vs. 108 + or - 16 vs. 72 + or - 8 beats x min(-1), respectively). The time domain measure pNN50 (37.3 + or - 16.9 vs. 14.1 + or - 10.1 vs. 22.0 + or - 12.2%, respectively), and the R-R interval (0.72 + or - 0.26 vs. 0.59 + or - 0.11, vs. 0.86 + or - 0.24, respectively) showed a significant decrease in DIVE compared to PRE and POST, while no changes were detected in the frequency domain indices between measurements. During POST, the square root of the mean of squared differences between successive intervals returned to PRE levels, but pNN50 values remained decreased at DIVE levels.

CONCLUSIONS

These findings suggest a decrease in parasympathetic indices during a psychologically challenging scuba dive and a delay in vagal reactivation during the 20-minute period following the dive.

Quantitative Ultrasonography of Calcaneal Bone Mass and Its Relationship to Calcium Consumption Among Impoverished Hispanic Women

Perimenopausal Hispanic women need to be able to build and sustain peak bone mass, but this may be affected by their low socioeconomic status. This feasibility research study provided descriptive information on the relationship between calcium consumption and bone mass measured with sonography at the calcaneus. Little research exists to examine bone health with this specific age or ethnic group of women. This research found a strong positive correlation between the amount of self-reported calcium food consumed and the bone stiffness index recorded using quantitative sonography. The translational impact of this project will inform the development of culturally relevant patient education for Hispanic women of low socioeconomic status to encourage the development of peak bone mass.

Discouraged Advisees? The Influence of Gender, Ethnicity, and Education in the Use of Advice and Finance by UK SMEs

We investigate the influence of gender, ethnicity, and education in the use of external advice and finance by UK small and medium-sized enterprises (SMEs). A conceptual model of ‘discouraged advisees’ was developed as a framework for analysis of the results of a telephone survey of 400 SMEs. We found an association between the use of external advice and the ability to raise bank finance. Furthermore, both men and black and minority ethnic (BME) participants were more likely to use family and friends for advice, whilst women were twice as likely as men to use Business Link. BME business owners were discouraged from using less ‘trusted’ sources, such as Business Link, possibly believing them insufficiently tailored or that they would provide inappropriate advice. Therefore, the findings provide support for our conceptual model of discouraged advisees and have implications for the provision of advice for business owners from BME communities.

Complex interactions with several arms of the complement system dictate innate and humoral immunity to adenoviral vectors

The complement system is known to play critical roles in pathogen identification, initiation of innate immune responses and facilitation of adaptive immune responses. Several studies have suggested that recombinant adenoviruses (rAds) interact with proteins of the complement system within minutes of administration. In this study, we assessed the roles of the alternative (Factor B), classical (C1q and C4) and common (C3) arms of the complement system in the innate and humoral response to systemic rAd administration using mice genetically deficient for each of these functions. Although most plasma cytokines and chemokines induced by Ads appeared to be elicited in a C3-dependent manner, we found that rAd-induced thrombocytopenia was dependent on Factor B and C3, implicating the alternative pathway as responsible for this response. Alteration of the complement-dependent transcriptome response after rAd-induced liver gene expression was also found to be Factor B- and C3-dependent. Ad interactions with the classical and alternative arms of the complement system can also be redundant, as many complement-dependent, Ad-induced innate immune responses appeared to be primarily C3-dependent. We also identified a C3 dependence of Ad-mediated induction of the nuclear factor-kappaB (NF-kappaB) activation pathway. Finally, we confirmed that humoral immune responses to the vector capsid, and the transgene it encodes, are also complement-dependent.

Use of beta-lactamase to hydrolyse interfering antibiotics in vitamin B12 microbiological assay using Lactobacillus leichmannii

The presence of certain antibiotics in patients' sera can invalidate microbiological assays for vitamin B12 using Lactobacillus leichmannii by inhibiting organism growth. Analysis of 3291 consecutive serum vitamin B12 assays in a large general hospital service showed inhibition of growth in 303 samples (9.2%). In nearly all cases the interfering substance was a beta-lactam antibiotic. The value of using a beta-lactamase preparation to eliminate antibiotic effects was studied using antibiotic-containing patient sera and also normal serum to which antibiotics were added. In-vitro additions of penicillins, cephalosporins, and other antibiotics to normal serum resulted in varying levels of organism inhibition, but excellent recovery of a control value after treatment with beta-lactamase (greater than 98%). Patient sera showing inhibition were reassayed in duplicate following treatment with beta-lactamase (n = 200), the overall effectiveness of the treatment being verified by the excellent recovery (greater than 98%) of a cyanocobalamin 'spike' added to a control. In only 0.2% of cases (6 of 3291 samples) was this treatment ineffective and it has thus proved an efficient method of eliminating the problem of antibiotic interference in the vitamin B12 microbiological assay.

The value of the erythrocyte indices as a screening procedure in predicting nutritional deficiencies

The results of a large number of nutritional screen requests (n = 871) were compared with corresponding values of erythrocyte indices considered predictive of nutritional deficiencies to determine if such indices could be used in a prospective screening procedure to restrict the number of serum vitamin B12, folate, and ferritin assays. Low mean cell haemoglobins (MCH less than 27 pg) were found to be superior to low mean cell volumes (MCV less than 77 fl), in predicting low serum ferritin values. The occurrence of deficient ferritin values was 90% when the MCH was very low (MCH less than 23 pg). Vitamin B12 or folate deficiency could not be predicted from the MCV. A normal MCV was found in more than 55% of vitamin B12 deficient samples and some 30% of serum B12 deficients (less than 150 micrograms/l) showed no evidence of anaemia (Hb greater than 12 gm/dl) or macrocytosis (MCV less than 100 fl). It would not seem appropriate to use erythrocyte indices alone as a method of selecting samples for further investigation of folate or vitamin B12 status.

Wild-type adenoviruses from groups A-F evoke unique innate immune responses, of which HAd3 and SAd23 are partially complement dependent

Alternative human and non-human Ad serotype vectors are currently studied for gene therapy and/or vaccine applications to capitalize upon their likely ability to avoid pre-existing immunity to HAd5. However, relatively little attention has been given to the nature and scope of innate immune responses generated by alternative Ad serotypes. In this study, we characterized several innate immune responses after intravenous administration of wild-type Ad serotypes HAd31, HAd3, HAd5, HAd37, SAd23 and HAd41, representing groups A-F, respectively. Notably, biodistribution studies revealed significant differences between the serotypes, with high levels of HAd3 genomes found in the liver and lung, and HAd37 genomes found in the spleen after systemic administration. Relative to similar treatments with other Ad serotypes, HAd3 and SAd23 induced altered innate immune responses, illustrated by induction of higher levels of cellular gene transcription in several tissues, and higher plasma levels of cytokines and chemokines. We also investigated whether complement interactions have a role in HAd3- and SAd23-induced responses. We confirmed complement dependent gene transcription, plasma cytokine/chemokine responses, and liver toxicities incurred after administration of HAd3 and SAd23. This study highlights the potential benefits and/or limitations to the proposed use of alternative Ad serotypes for gene therapy or vaccine applications.

Intensive rotational grazing assists control of gastrointestinal nematodosis of sheep in a cool temperate environment with summer-dominant rainfall

While rotational grazing methods have an accepted role in the management of gastrointestinal nematodosis (GIN) of small ruminants in humid tropical regions, their efficacy and application in cool temperate regions is more controversial. This study evaluated GIN over 2 years in three classes of fine wool Merino sheep (lambs, hoggets and ewes) under three different sheep management systems in a cool tableland environment near Armidale NSW Australia (950m altitude, 30 degrees 31'S, 151 degrees 39'E). The management systems were High input (HI) with high fertiliser inputs, a target of 100% sown pasture, high stocking rate (13.4 dry sheep equivalents/ha) and relatively long grazing periods; Typical (TYP) New England management system with moderate fertiliser inputs and stocking rate (9.3DSE/ha) and relatively long grazing periods; and Intensive rotational grazing (IRG) with moderate fertiliser inputs and stocking rate (8.8DSE/ha) but very short (mean 5 days) grazing periods and long (mean 103 days) rest periods. Twenty sheep of each class in each management treatment were sampled monthly for faecal worm egg counts (WEC, followed by larval differentiation), and body weights with a blood sample taken for haematology every second month. The proportion of sheep with WEC above zero did not differ between management systems but the magnitude of WEC did, with sheep under IRG displaying lower mean WEC than those on the other treatments (IRG: 326, HI: 594, TYP: 536, eggs/g P<0.0001). This was despite a significantly longer mean interval between anthelmintic treatments (IRG: 144 days, HI: 77 days, TYP: 78 days, P<0.0001). The IRG management system also influenced the composition of the infections with sheep on this treatment having a significantly lower proportion of Haemonchus contortus in their faecal cultures (IRG: 59.7%, HI: 79.4%, TYP: 80.9%, P<0.05) and a significantly higher proportion of Trichostrongylus spp. Sheep on the IRG treatment also had a significantly higher haematocrit (HCT) than those on the other management systems. Despite the lower WEC and higher HCT, sheep under IRG also had significantly lower bodyweights and fleece weights overall, although this was only evident in sheep raised to adulthood prior to the experiment, not those raised during the 2-year experimental period. The results demonstrate that IRG systems with short grazing periods and long rest periods between grazing events can assist with control of GIN in cool temperate climates where H. contortus is the dominant parasite.

Folic acid metabolism and mechanisms of neural tube defects

Folate acts as a cofactor for enzymes involved in DNA and RNA biosynthesis. Folate is also involved in the supply of methyl groups to the so-called methylation cycle, which uses methionine and makes homocysteine. The folate cofactor, N5-methyltetrahydrofolate, donates its methyl group to a vitamin B12-dependent enzyme, methionine synthase, which recycles homocysteine back to methionine. The cell's ability to methylate important compounds such as proteins, lipids and myelin will be compromised by deficiency of folate or vitamin B12, resulting in impaired cellular function. Methionine synthase plays another role: it converts circulating N5-methyltetrahydrofolate into tetrahydrofolate. The latter but not the former can act as a substrate for polyglutamate synthase, thereby becoming retained in the cell as polyglutamate. Interruption of DNA biosynthesis or methylation reactions could prevent the proper closure of the neural tube. Such inhibition could be caused by simple deficiency of either folic acid or vitamin B12. Studies comparing serum folate and vitamin B12 status in women who have had an affected pregnancy to those in control women indicate no difference between the two groups and show that most cases are not clinically deficient in either vitamin. A small number of studies using the level of folate in red blood cells, which is a better reflection of tissue stores, confirm this, suggesting instead a metabolic impairment in the biochemical functions of one of these vitamins. The trials using folic acid to prevent neural tube defects thus seem to be effectively overcoming a metabolic block rather than treating folate deficiency.

Vitamin B12 and folate deficiency in later life

OBJECTIVES

to examine the prevalence of vitamin B12 deficiency and folate deficiency in later life in representative samples of the elderly population in the United Kingdom.

DESIGN

a population-based cross-sectional analysis of 3,511 people aged 65 years or older from three studies was used to estimate the age-specific prevalence of vitamin B12 deficiency and of folate deficiency. Vitamin B12 deficiency is conventionally diagnosed if serum vitamin B12 < 150 pmol/l ('low vitamin B12'). We defined 'metabolically significant vitamin B12 deficiency' as vitamin B12 < 200 pmol/l and blood total homocysteine >20 micro mol/l. Folate deficiency, which usually refers to serum folate <5 nmol/l, was defined as 'metabolically significant' if serum folate was <7 nmol/l and homocysteine >20 micro mol/l.

RESULTS

the prevalence of vitamin B12 deficiency, whether defined as low vitamin B12 or metabolically significant vitamin B12 deficiency increased with age in all three studies, from about 1 in 20 among people aged 65-74 years to 1 in 10 or even greater among people aged 75 years or greater. The prevalence of folate deficiency also increased with age, and was similar to that for vitamin B12 deficiencies, but only about 10% of people with low vitamin B12 levels also had low folate levels.

CONCLUSION

the high prevalence of vitamin B12 and folate deficiency observed in older people indicates a particular need for vigilance for deficiency of these vitamins. Reliable detection and treatment of vitamin deficiency could reduce the risk of deficiency-related disability in old age.