Glutamine deprivation alters the origin and function of cancer cell exosomes.

Exosomes are secreted extracellular vesicles carrying diverse molecular cargos, which can modulate recipient cell behaviour. They are thought to derive from intraluminal vesicles formed in late endosomal multivesicular bodies (MVBs). An alternate exosome formation mechanism, which is conserved from fly to human, is described here, with exosomes carrying unique cargos, including the GTPase Rab11, generated in Rab11-positive recycling endosomal MVBs. Release of Rab11-positive exosomes from cancer cells is increased relative to late endosomal exosomes by reducing growth regulatory Akt/mechanistic Target of Rapamycin Complex 1 (mTORC1) signalling or depleting the key metabolic substrate glutamine, which diverts membrane flux through recycling endosomes. Vesicles produced under these conditions promote tumour cell proliferation and turnover and modulate blood vessel networks in xenograft mouse models in vivo. Their growth-promoting activity, which is also observed in vitro, is Rab11a-dependent, involves ERK-MAPK-signalling and is inhibited by antibodies against amphiregulin, an EGFR ligand concentrated on these vesicles. Therefore, glutamine depletion or mTORC1 inhibition stimulates release from Rab11a compartments of exosomes with pro-tumorigenic functions, which we propose promote stress-induced tumour adaptation.

High-Efficiency, 80 mm Aperture Metalens Telescope.

Metalenses promise potential for a paradigm shift of conventional optical devices. However, the aperture sizes of metalenses are usually bound within hundreds of micrometers by the commonly used fabrication methods, limiting their usage on practical optical devices like telescopes. Here, for the first time, we demonstrate a high-efficiency, single-lens, refractive metalens telescope. We developed a mass production-friendly workflow for fabricating wafer-scale (80 mm aperture) metalenses using deep-ultraviolet (DUV) photolithography. Our metalens works in the near-infrared region with nearly diffraction-limited focal spot sizes and a high peak focusing efficiency of 80.84% at 1450 nm experimentally. Based on the metalens, we built a single-lens telescope and acquired images of the lunar surface, revealing its geographical structures. We believe our demonstration of the metalens telescope proves the exciting potential lying in the metasurfaces and could bring new possibilities for areas involving large optical systems, including geosciences, planetary observation, and astrophysical science.

The influence of maturation on exercise-induced cardiac remodelling and haematological adaptation.

Cardiovascular and haematological adaptations to endurance training facilitate greater maximal oxygen consumption ( V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ ), and such adaptations may be augmented following puberty. Therefore, we compared left ventricular (LV) morphology (echocardiography), blood volume, haemoglobin (Hb) mass (CO rebreathing) and V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ in endurance-trained and untrained boys (n = 42, age = 9.0-17.1 years, V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$  = 61.6 ± 7.2 ml/kg/min, and n = 31, age = 8.0-17.7 years, V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$  = 46.5 ± 6.1 ml/kg/min, respectively) and girls (n = 45, age = 8.2-17.0 years, V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$  = 51.4 ± 5.7 ml/kg/min, and n = 36, age = 8.0-17.6 years, V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$  = 39.8 ± 5.7 ml/kg/min, respectively). Pubertal stage was estimated via maturity offset, with participants classified as pre- or post-peak height velocity (PHV). Pre-PHV, only a larger LV end-diastolic volume/lean body mass (EDV/LBM) for trained boys (+0.28 ml/kg LBM, P = 0.007) and a higher Hb mass/LBM for trained girls (+1.65 g/kg LBM, P = 0.007) were evident compared to untrained controls. Post-PHV, LV mass/LBM (boys: +0.50 g/kg LBM, P = 0.0003; girls: +0.35 g/kg LBM, P = 0.003), EDV/LBM (boys: +0.35 ml/kg LBM, P < 0.0001; girls: +0.31 ml/kg LBM, P = 0.0004), blood volume/LBM (boys: +12.47 ml/kg LBM, P = 0.004; girls: +13.48 ml/kg LBM, P = 0.0002.) and Hb mass/LBM (boys: +1.29 g/kg LBM, P = 0.015; girls: +1.47 g/kg LBM, P = 0.002) were all greater in trained versus untrained groups. Pre-PHV, EDV (R2adj  = 0.224, P = 0.001) in boys, and Hb mass and interventricular septal thickness (R2adj  = 0.317, P = 0.002) in girls partially accounted for the variance in V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ . Post-PHV, stronger predictive models were evident via the inclusion of LV wall thickness and EDV in boys (R2adj  = 0.608, P < 0.0001), and posterior wall thickness and Hb mass in girls (R2adj  = 0.490, P < 0.0001). In conclusion, cardiovascular adaptation to exercise training is more pronounced post-PHV, with evidence for a greater role of central components for oxygen delivery. KEY POINTS: It has long been hypothesised that cardiovascular adaptation to endurance training is augmented following puberty. We investigated whether differences in cardiac and haematological variables exist, and to what extent, between endurance-trained versus untrained, pre- and post-peak height velocity (PHV) children, and how these central factors relate to maximal oxygen consumption. Using echocardiography to quantify left ventricular (LV) morphology and carbon monoxide rebreathing to determine blood volume and haemoglobin mass, we identified that training-related differences in LV morphology are evident in pre-PHV children, with haematological differences also observed between pre-PHV girls. However, the breadth and magnitude of cardiovascular remodelling was more pronounced post-PHV. Cardiac and haematological measures provide significant predictive models for maximal oxygen consumption ( V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ ) in children that are much stronger post-PHV, suggesting that other important determinants within the oxygen transport chain could account for the majority of variance in V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ before puberty.

Short-Term Effects of "Composite" Training on Strength, Jump, and Sprint Performance in Hurling Players.

ABSTRACT: Byrne, PJ, Moody, JA, Cooper, S-M, Farrell, E, and Kinsella, S. Short-term effects of "composite training" on strength, jump, and sprint performance in hurling players. J Strength Cond Res 36(8): 2253-2261, 2022-The purpose of this study was to compare the short-term effects of "composite" training to sprint training on strength, jump, and sprint acceleration performance in hurling players. A randomized counterbalanced group design with baseline test, pretest and post-test measures was used. Twenty-five hurling players volunteered to participate and 21 completed the study. Subjects were divided into a "composite" (COMP group, n = 10) or a sprint training (SPRINT group, n = 11) group. Both groups trained twice per week for 7 weeks with the SPRINT group performing 6 repetitions of 20 m sprints and the COMP group completing 6 repetitions (1 repetition = 3 bounce drop jumps [BDJs] with a 20 m sprint after 15 seconds recovery). Significant differences existed pretraining to post-training for the COMP group for BDJ contact time (-7.25%; p = 0.05) and countermovement jump (CMJ) variables (height: 7.43%, p = 0.006; force: 5.24%, p = 0.05; power: 15.11%, p = 0.001). No significant differences were found between groups at baseline and for group by time interactions. Significant improvements were observed pretraining to post-training in both groups for the following: absolute 3 repetition maximum (3RM) back squat strength (12.73-17.62%, p = 0.01), 5 m (5.74-9.49%, p = 0.006-0.04), 10 m (4.27-5.59%, p = 0.007-0.02), and 20 m (3.35-3.98%, p = 0.003-0.01). In conclusion, "composite" training is effective in enhancing fast stretch-shortening cycle efficiency inducing CMJ force and power augmentation. However, "composite" and sprint training are effective training approaches for enhancing maximal strength and sprint performance in a time efficient manner in hurling players.

Acute Effects of "Composite" Training on Neuromuscular and Fast Stretch-Shortening Cycle Drop Jump Performance in Hurling Players.

ABSTRACT: Byrne, PJ, Moody, JA, Cooper, SM, and Kinsella, S. Acute effects of "composite" training on neuromuscular and fast stretch-shortening cycle drop jump performance in hurling players. J Strength Cond Res 35(12): 3474-3481, 2021-"Composite" training is a term developed by the authors and defined as the combination of a plyometric exercise with an explosive activity such as a sprint run, performed as a "combined repetition"/session. The purposes of this study were to investigate the acute effect of a "composite" training session on neuromuscular and fast stretch-shortening cycle bounce drop jumps (BDJs) in hurling players' immediately, after session, and after 7 days of recovery. Eight hurling players first completed a drop jump test to identify individual BDJ drop height, followed 72 hours later with a single "composite" training session. Three repetition maximum (3RM) back squat strength, BDJ, countermovement jump (CMJ), and sprint performance testing were performed 10 minutes before and immediately after session and 7 days after session. An analysis of variance reported a significant decrease in CMJ measures (height, velocity, and eccentric rate of force development) and sprint performance from presession to postsession (p ≤ 0.05). Moreover, a significant increase was evident for CMJ performance (height and power), sprint performance (5 and 20 m), 3RM back squat strength, and BDJ performance (reactive strength index and height) from postsession to post-7-day recovery (p ≤ 0.05). Pairwise comparisons indicated that absolute and relative 3RM strength significantly increased from presession to post-7 days (absolute 3RM: p = 0.0001; relative 3RM: p = 0.01). The findings indicate that "composite" training results in an immediate decline in CMJ measures after session possibly due to acute muscle fatigue, and supercompensation augments maximum lower-limb strength after 7 days of recovery.

Potentiating Response to Drop-Jump Protocols on Sprint Acceleration: Drop-Jump Volume and Intrarepetition Recovery Duration.

Byrne, PJ, Moody, JA, Cooper, SM, Callanan, D, and Kinsella, S. Potentiating response to drop-jump protocols on sprint acceleration: drop-jump volume and intrarepetition recovery duration. J Strength Cond Res 34(3): 717-727, 2020-The purpose of this study was to investigate the postactivation potentiation response first to bounce drop jump (BDJ) volume; second, BDJ intrarepetition recovery duration and recovery duration between BDJs and 20-meter (including 5- and 10-m split times) sprint performance. The study was undertaken in 2 parts, the first part compared different volumes of BDJs and the second part compared different BDJ intrarepetition recovery periods. The effect of recovery periods between the BDJs and the subsequent 20-m sprints was examined in both parts 1 and 2 (15 seconds, 4, 8, and 12 minutes). Fourteen (mean ± SD: age = 20.83 ± 1.26 years; height = 1.77 ± 0.04 m; and mass = 74.89 ± 6.07 kg) (part 1) and 15 (mean ± SD: age = 20.64 ± 1.00 years; height = 1.78 ± 0.06 m; and mass = 75.67 ± 6.28 kg) (part 2) male collegiate and club hurling players volunteered to participate. A randomized cross-over design was used to compare BDJ volumes (1, 2, and 3 sets of 3 repetitions) and BDJ intrarepetition recovery time (15 vs. 60 seconds) after a warm-up followed by 2 baseline 20-m sprints. The results in part 1 reported a significant improvement in 5- and 10-m sprint time for 1 set of 3 BDJs between baseline and 4 minutes (5 m: -2.34%, p = 0.04, effect size [ES] = -0.043; 10 m: -1.42%, p = 0.03, ES = -0.35), and baseline and 12 minutes (5 m: -3.33%, p = 0.03, ES = -0.57; 10 m: -2.13%, p = 0.01, ES = -0.52). Part 2 reported a significant improvement in 5-m sprint time between baseline and 15 seconds (5 m: -3.38%, p = 0.01, ES = -0.83; 10 m: -2.07%, p = 0.02, ES = -0.58) after the BDJs. The findings support the use of 1 set of 3 BDJs using a 15-second intrarepetition recovery period to maximize 5-, 10-, and 20-m sprint performance after 15 seconds of recovery after the final BDJ in hurling players. The acute response to this BDJ protocol proves to be time efficient and effective in acutely improving sprint acceleration.

The Effect of Interactions between Item Discrimination and Item Difficulty on Fit Statistics.

Residual-based fit statistics are among the most common indicators of fit to the Rasch model. There is considerable discussion in the literature of the efficacy of item fit statistics in detecting measurement disturbances. However, to date there has been no investigation of whether these fit statistics are robust to interactions between item discrimination and item difficulty. This study uses simulations to investigate whether interaction effects occur for fit statistics commonly used with the Rasch model. It is found that when the parameters are estimated with the Rasch model, the values of certain item fit statistics vary depending on the interaction between location and discrimination. Specifically, in the study, OUTFIT MNSQ and INFIT MNSQ provide a relatively consistent index of item discrimination across a range of item difficulties, whereas the t-statistic and the log transformed fit residual vary in a systematic fashion that depends on item location.

The independent effects of hypovolaemia and pulmonary vasoconstriction on ventricular function and exercise capacity during acclimatisation to 3800 m.

KEY POINTS: We sought to determine the isolated and combined influence of hypovolaemia and hypoxic pulmonary vasoconstriction on the decrease in left ventricular (LV) function and maximal exercise capacity observed under hypobaric hypoxia. We performed echocardiography and maximal exercise tests at sea level (344 m), and following 5-10 days at the Barcroft Laboratory (3800 m; White Mountain, California) with and without (i) plasma volume expansion to sea level values and (ii) administration of the pulmonary vasodilatator sildenafil in a double-blinded and placebo-controlled trial. The high altitude-induced reduction in LV filling and ejection was abolished by plasma volume expansion but to a lesser extent by sildenafil administration; however, neither intervention had a positive effect on maximal exercise capacity. Both hypovolaemia and hypoxic pulmonary vasoconstriction play a role in the reduction of LV filling at 3800 m, but the increase in LV filling does not influence exercise capacity at this moderate altitude. ABSTRACT: We aimed to determine the isolated and combined contribution of hypovolaemia and hypoxic pulmonary vasoconstriction in limiting left ventricular (LV) function and exercise capacity under chronic hypoxaemia at high altitude. In a double-blinded, randomised and placebo-controlled design, 12 healthy participants underwent echocardiography at rest and during submaximal exercise before completing a maximal test to exhaustion at sea level (SL; 344 m) and after 5-10 days at 3800 m. Plasma volume was normalised to SL values, and hypoxic pulmonary vasoconstriction was reversed by administration of sildenafil (50 mg) to create four unique experimental conditions that were compared with SL values: high altitude (HA), Plasma Volume Expansion (HA-PVX), Sildenafil (HA-SIL) and Plasma Volume Expansion with Sildenafil (HA-PVX-SIL). High altitude exposure reduced plasma volume by 11% (P < 0.01) and increased pulmonary artery systolic pressure (19.6 ± 4.3 vs. 26.0 ± 5.4, P < 0.001); these differences were abolished by PVX and SIL respectively. LV end-diastolic volume (EDV) and stroke volume (SV) were decreased upon ascent to high altitude, but were comparable to sea level in the HA-PVX trial. LV EDV and SV were also elevated in the HA-SIL and HA-PVX-SIL trials compared to HA, but to a lesser extent. Neither PVX nor SIL had a significant effect on the LV EDV and SV response to exercise, or the maximal oxygen consumption or peak power output. In summary, at 3800 m both hypovolaemia and hypoxic pulmonary vasoconstriction contribute to the decrease in LV filling, but restoring LV filling does not confer an improvement in maximal exercise performance.

Experimental and quantitative imaging techniques in interstitial lung disease.

Interstitial lung diseases (ILDs) are a heterogeneous group of conditions, with a wide and complex variety of imaging features. Difficulty in monitoring, treating and exploring novel therapies for these conditions is in part due to the lack of robust, readily available biomarkers. Radiological studies are vital in the assessment and follow-up of ILD, but currently CT analysis in clinical practice is qualitative and therefore somewhat subjective. In this article, we report on the role of novel and quantitative imaging techniques across a range of imaging modalities in ILD and consider how they may be applied in the assessment and understanding of ILD. We critically appraised evidence found from searches of Ovid online, PubMed and the TRIP database for novel and quantitative imaging studies in ILD. Recent studies have explored the capability of texture-based lung parenchymal analysis in accurately quantifying several ILD features. Newer techniques are helping to overcome the challenges inherent to such approaches, in particular distinguishing peripheral reticulation of lung parenchyma from pleura and accurately identifying the complex density patterns that accompany honeycombing. Robust and validated texture-based analysis may remove the subjectivity that is inherent to qualitative reporting and allow greater objective measurements of change over time. In addition to lung parenchymal feature quantification, pulmonary vessel volume analysis on CT has demonstrated prognostic value in two retrospective analyses and may be a sign of vascular changes in ILD which, to date, have been difficult to quantify in the absence of overt pulmonary hypertension. Novel applications of existing imaging techniques, such as hyperpolarised gas MRI and positron emission tomography (PET), show promise in combining structural and functional information. Although structural imaging of lung tissue is inherently challenging in terms of conventional proton MRI techniques, inroads are being made with ultrashort echo time, and dynamic contrast-enhanced MRI may be used for lung perfusion assessment. In addition, inhaled hyperpolarised 129Xenon gas MRI may provide multifunctional imaging metrics, including assessment of ventilation, intra-acinar gas diffusion and alveolar-capillary diffusion. PET has demonstrated high standard uptake values (SUVs) of 18F-fluorodeoxyglucose in fibrosed lung tissue, challenging the assumption that these are 'burned out' and metabolically inactive regions. Regions that appear structurally normal also appear to have higher SUV, warranting further exploration with future longitudinal studies to assess if this precedes future regions of macroscopic structural change. Given the subtleties involved in diagnosing, assessing and predicting future deterioration in many forms of ILD, multimodal quantitative lung structure-function imaging may provide the means of identifying novel, sensitive and clinically applicable imaging markers of disease. Such imaging metrics may provide mechanistic and phenotypic information that can help direct appropriate personalised therapy, can be used to predict outcomes and could potentially be more sensitive and specific than global pulmonary function testing. Quantitative assessment may objectively assess subtle change in character or extent of disease that can assist in efficacy of antifibrotic therapy or detecting early changes of potentially pneumotoxic drugs involved in early intervention studies.

Hyperpolarised xenon magnetic resonance spectroscopy for the longitudinal assessment of changes in gas diffusion in IPF.

Prognosticating idiopathic pulmonary fibrosis (IPF) is challenging, in part due to a lack of sensitive biomarkers. A recent article in Thorax described how hyperpolarised xenon magnetic resonance spectroscopy may quantify regional gas exchange in IPF lungs. In a population of patients with IPF, we find that the xenon signal from red blood cells diminishes relative to the tissue/plasma signal over a 12-month time period, even when the diffusion factor for carbon monoxide is static over the same time period. We conclude that hyperpolarised 129Xe MR spectroscopy may be sensitive to short-term changes in interstitial gas diffusion in IPF.

Adaptation of myocardial twist in the remodelled athlete's heart is not related to cardiac output.

NEW FINDINGS: What is the central question of this study? What is the role of heart muscle function in the increased output of remodelled, larger hearts? What is the main finding and its importance? The greater stroke volume of endurance athletes is not associated with enhanced function of the heart muscle (i.e. left ventricular twist, torsion and twist-to-shortening) in normal and low-oxygen environments. These data indicate that, in the process of cardiac adaptation, left ventricular twist may play an important role that is not related to generating a larger output. Since enlarged hearts with low output can develop in disease, the present findings may influence the future interpretation of heart muscle function in patients. ABSTRACT: Despite increased stroke volume (SV), 'athlete's heart' has been proposed to have a similar left ventricular (LV) muscle function - as represented by LV twist - compared with the untrained state. However, the underpinning mechanisms and the associations between SV/cardiac output and LV twist during exercise are unknown. We hypothesised that endurance athletes would have a significantly lower twist-to-shortening ratio (TwSR, a parameter that relates twist to the shortening of heart muscle layers) at rest, but significantly greater LV muscle function during exercise. Eleven endurance trained male runners and 13 untrained males were tested at rest and during supine cycling exercise in normoxia and hypoxia (increased cardiac output but unaltered SV). Despite the expected cardiac remodelling in endurance athletes, LV twist, torsion, TwSR, strain and strain rate ('LV systolic mechanics') did not differ significantly between groups (P > 0.05). Structural remodelling, as per relative wall thickness, and LV twist did not correlate (r2  = 0.04, P = 0.33). In normoxia and hypoxia, exercise increased LV systolic mechanics in both groups (P < 0.001), but with different relationships to SV and cardiac output. Conversely to our hypothesis, hearts of different size had similar LV systolic mechanics, suggesting that similar twist, torsion and TwSR at rest and during exercise irrespective of cardiac output may be an important mechanism in healthy hearts. We hypothesise that the regulatory 'purpose' of LV twist may be related to the sensing of maximal cardiac myofibre stress, which may act as a biologically purposeful limiter to contraction.

IL-10-producing, ST2-expressing Foxp3+ T cells in multiple sclerosis brain lesions.

CD4+Foxp3+ T regulatory (Treg) cells provide a key defence against inflammatory disease, but also have an ability to produce pro-inflammatory cytokines. The evidence for these two possibilities in multiple sclerosis (MS) is controversial. However, this has largely been based on studies of circulating Treg cells derived from peripheral blood, rather than the central nervous system. We show that Foxp3+ cells in the brains of MS patients predominantly produce interleukin-10 (IL-10) and show high expression of the IL-33 receptor ST2 (associated with potent Treg function), indicating that Treg in the inflamed brain maintain their suppressive function.

Solid, 3-mirror Fabry-Perot etalon.

We present modeling and performance of a solid, fused silica, 3-mirror Fabry-Perot-type etalon. 3-mirror etalons have been known for decades to have superior theoretical performance but for the first time we demonstrate an etalon with sufficient quality to realize the benefits of the more complex design. 3-mirror etalons have better passband shape and higher contrast ratio enabling significantly improved wavelength separation. We show the optical cavity design and construction of the new etalon and show >95% peak transmission, improved passband shape and 20 dB better out-of-band rejection than a similar 2-mirror etalon.

Perceptions of orthodontic specialist training in the United Kingdom: a national survey of postgraduate orthodontic student opinion.

INTRODUCTION: Postgraduate orthodontic education is highly challenging. There is a lack of evidence regarding orthodontic postgraduates' perceptions of their orthodontic education in the United Kingdom. In addition, no study has been conducted to compare the postgraduate orthodontic training experience between UK trainees and international postgraduates. OBJECTIVES: (1) To investigate orthodontic UK trainees' and international postgraduates' perception and satisfaction of their orthodontic education. (2) To compare postgraduate orthodontic training experience between UK trainees and international postgraduates. (3) To compare orthodontic caseload between UK trainees and international postgraduates. METHODS: Utilizing a descriptive, cross-sectional survey, conducted through a web-based self-administered questionnaire, the sample population consisted of all 189 orthodontic postgraduates in the United Kingdom. RESULTS: One hundred and twenty-five questionnaires were completed resulting in a response rate of 66.1%. All three academic years were evenly represented. Ninety five (76%) respondents rated the quality of their postgraduate orthodontic education as excellent. Over 90% of third year postgraduates felt the quality of their education was excellent. The majority of orthodontic trainees (n = 98, 78.4%) were satisfied with the number of cases. Apart from the first year postgraduates, other postgraduates regardless of UK trainee or international postgraduate status reported a high number of cases in treatment, with 45 (36%) respondents treating more patients than the recommended range of 80-120. Postgraduates' responses were less positive regarding their ability to influence the delivery of their programme, whether their programme represented value for money and the fairness of their training. Most of the respondents believed that UK trainees had an advantage in communicating with patients. CONCLUSION: The majority of orthodontic postgraduates rated the quality of their postgraduate education as excellent. Apart from first year postgraduates, other postgraduates irrespective of UK trainee or international postgraduate status reported a high number of cases in treatment. There was no difference in caseload between UK trainee and international postgraduate groups.

Nickel titanium springs versus stainless steel springs: A randomized clinical trial of two methods of space closure.

OBJECTIVE: To compare the clinical performance of nickel titanium (NiTi) versus stainless steel (SS) springs during orthodontic space closure. DESIGN: Two-centre parallel group randomized clinical trial. SETTING: Orthodontic Department University of Manchester Dental Hospital and Orthodontic Department Countess of Chester Hospital, United Kingdom. SUBJECTS AND METHODS: Forty orthodontic patients requiring fixed appliance treatment were enrolled, each being randomly allocated into either NiTi (n = 19) or SS groups (n = 21). Study models were constructed at the start of the space closure phase (T0) and following the completion of space closure (T1). The rate of space closure achieved for each patient was calculated by taking an average measurement from the tip of the canine to the mesiobuccal groove on the first permanent molar of each quadrant. RESULTS: The study was terminated early due to time constraints. Only 30 patients completed, 15 in each study group. There was no statistically significant difference between the amounts of space closed (mean difference 0.17 mm (95%CI -0.99 to 1.34; P = 0.76)). The mean rate of space closure for NiTi coil springs was 0.58 mm/4 weeks (SD 0.24) and 0.85 mm/4 weeks (SD 0.36) for the stainless steel springs. There was a statistically significant difference between the two groups (P = 0.024), in favour of the stainless steel springs, when the mean values per patient were compared. CONCLUSIONS: Our study shows that stainless steel springs are clinically effective; these springs produce as much space closure as their more expensive rivals, the NiTi springs.

Lateral-transfer recirculating etalon spectrometer.

We describe a Fabry-Perot etalon spectrometer with a novel light recirculation scheme to generate simultaneous parallel wavelength channels with no moving parts. This design uses very simple optics to recirculate light reflected from near normal incidence from the etalon at successively higher angles of incidence. The spectrometer has the full resolution of a Fabry-Perot with significantly improved photon efficiency in a compact, simple design with no moving parts. We present results from a conceptual prototype and a corresponding model.

Relationships between Cardiorespiratory and Muscular Fitness with Cardiometabolic Risk in Adolescents.

This study examined the independent relationships between cardiorespiratory and muscular fitness with cardiometabolic risk in adolescents. Subjects were 192 adolescents (118 boys), aged 15-17.5 years. The 2 m multi-stage fitness test assessed cardiorespiratory fitness and the counter movement jump assessed muscular fitness. Additional measures included interleukin-6, C-reactive protein, adiponectin, fibrinogen and plasminogen activator inhibitor-1. Regression analysis revealed that cardiorespiratory fitness was negatively related to cardiometabolic risk (ß = -0.014, p < 0.001). With additional adjustment for muscular fitness the relationship remained significant (ß = -0.015, p < 0.001). Muscular fitness was negatively related to cardiometabolic risk (ß = -0.021, p < 0.001) and remained significant after adjustment for cardiorespiratory fitness. Participants in the least-fit quartile for both cardiorespiratory and muscular fitness had significantly poorer cardiometabolic risk scores than those in the other quartiles. Findings revealed that muscular and cardiorespiratory fitness are significantly associated with cardiometabolic risk independently of one another.

Development of novel calibration model(s) to predict whole-body density in professional football players.

INTRODUCTION: Questions continue to be raised about the validity that is in existence to estimate Db, in professional male footballer players. METHODS: Phase 1: n = 28 anthropometric variables were used on n = 206 footballers, using regression analyses to determine standard error of estimate and R2. A cut-off correlation coefficient set at r = 0.950 and 90% R2. Phase 2: all variables (z-scores, x- = 0.0, SD = ±1.0) to help reduce heteroscedasticity, ß, r, t, significance of t and P-values were calculated. Phase 3: a forced stepwise-backwards regression analysis approach with nine predictors which met the acceptance criteria (r = 0.950, R2 = 90% and ß weights) was used to develop a 'best fit' and a 'practical' calibration model. Phase 4: cross-validation of the two newly developed calibration method using LoA. RESULTS: The 'best fit' model SEM (0.115 g ml-1), the highest R2 (6.6%) (P ≤ 0.005), whereas the 'practical' calibration model SEM (0.115 g ml-1), R2 (4.7%) (P ≤ 0.005) with r values = 0.271 and 0.596 and R2 (%) coefficients = 0.3526 for the 'best fit' and 'practical' calibration models, respectively (P = 0.01). CONCLUSIONS: The two calibration models supported an ecologically and statistically valid contribution and can provide sound judgements about professional footballers' body composition.