Experimental evidence of mosaic structure in strongly supercooled molecular liquids.

When a liquid is cooled to produce a glass its dynamics, dominated by the structural relaxation, become very slow, and at the glass-transition temperature Tg its characteristic relaxation time is about 100 s. At slightly elevated temperatures (~1.2 Tg) however, a second process known as the Johari-Goldstein relaxation, ßJG, decouples from the structural one and remains much faster than it down to Tg. While it is known that the ßJG-process is strongly coupled to the structural relaxation, its dedicated role in the glass-transition remains under debate. Here we use an experimental technique that permits us to investigate the spatial and temporal properties of the ßJG relaxation, and give evidence that the molecules participating in it are highly mobile and spatially connected in a system-spanning, percolating cluster. This correlation of structural and dynamical properties provides strong experimental support for a picture, drawn from theoretical studies, of an intermittent mosaic structure in the deeply supercooled liquid phase.

A microscopic look at the Johari-Goldstein relaxation in a hydrogen-bonded glass-former.

Understanding the glass transition requires getting the picture of the dynamical processes that intervene in it. Glass-forming liquids show a characteristic decoupling of relaxation processes when they are cooled down towards the glassy state. The faster (ßJG) process is still under scrutiny, and its full explanation necessitates information at the microscopic scale. To this aim, nuclear γ-resonance time-domain interferometry (TDI) has been utilized to investigate 5-methyl-2-hexanol, a hydrogen-bonded liquid with a pronounced ßJG process as measured by dielectric spectroscopy. TDI probes in fact the center-of-mass, molecular dynamics at scattering-vectors corresponding to both inter- and intra-molecular distances. Our measurements demonstrate that, in the undercooled liquid phase, the ßJG relaxation can be visualized as a spatially-restricted rearrangement of molecules within the cage of their closest neighbours accompanied by larger excursions which reach out at least the inter-molecular scale and are related to cage-breaking events. In-cage rattling and cage-breaking processes therefore coexist in the ßJG relaxation.

Contrasting two different interpretations of the dynamics in binary glass forming mixtures.

In a series of papers on binary glass-forming mixtures of tripropyl phosphate (TPP) with polystyrene (PS), Kahlau et al. [J. Chem. Phys. 140, 044509 (2014)] and Bock et al. [J. Chem. Phys. 139, 064508 (2013); J. Chem. Phys. 140, 094505 (2014); and J. Non-Cryst. Solids 407, 88-97 (2015)] presented the data on the dynamics of the two components studied over the entire composition range by several experimental methods. From these sets of data, obtained by multiple experimental techniques on mixtures with a large difference ΔTg ≈ 200 K between the glass transition temperatures of two starting glass formers, they obtained two α-relaxations, α1 and α2. The temperature dependence of the slower α1 is Vogel-Fulcher like, but the faster α2 is Arrhenius. We have re-examined their data and show that their α2-relaxation is the Johari-Goldstein (JG) ß-relaxation with Arrhenius T-dependence admixed with a true α2-relaxation having a stronger temperature dependence. In support of our interpretation of their data, we made dielectric measurements at elevated pressures P to show that the ratio of the α1 and α2 relaxation times, τα1(T,P)/τα2(T,P), is invariant to variations of T and P, while τα1(T,P) is kept constant. This property proves unequivocally that the α2-relaxation is the JG ß-relaxation, the precursor of the α1-relaxation. Subsequently, the true but unresolved α2-relaxation is recovered, and its relaxation times with much stronger temperature dependence are deduced, as expected for the α-relaxation of the TPP component. The results are fully compatible with those found in another binary mixture of methyltetrahydrofuran with tristyrene and PS with ΔTg ≈ 283 K, even larger than ΔTg ≈ 200 K of the mixture of TPP with PS, and in several polymer blends. The contrast between the two very different interpretations brought out in this paper is deemed beneficial for further progress in this research area.

Efficacy of a standardized extract of Matricariae chamomilla L., Melissa officinalis L. and tyndallized Lactobacillus acidophilus (HA122) in infantile colic: An open randomized controlled trial.

BACKGROUND: Infant colic (IC) is a prevalent physiological event of infants, which can disrupt the child's home environment. We aimed to investigate the effectiveness of a mixture of Matricariae chamomilla L., Melissa officinalis L. and tyndallized Lactobacillus acidophilus (HA122) compared with Lactobacillus reuteri DSM 17938 and with simethicone for the treatment of IC. METHODS: A multicenter randomized comparative study was conducted in infants with colic, according to Rome III criteria, who were randomly assigned to receive M. chamomilla L., M. officinalis L. and tyndallized L. acidophilus (HA122) (Colimil® Plus® ; Milte Italia Spa, Milan, Italy) (Group A), L. reuteri DSM 17938 (Group B) and simethicone (Group C). Treatment was given to subjects for 28 days. KEY RESULTS: One-hundred and seventy-six patients completed the study. Mean daily crying time at day 28 was significantly lower in group A (-44, 95% CI: -58 to -30, P<.001) and group B (-35, 95% CI: -49 to -20, P<.001) when compared to group C. No significant difference was observed between Group A and Group B (mean difference: -9 minutes, 95% CI -23 to +5, P=.205). At day 28, 39 of 57 (68.4%) of infants in Group C responded to the treatment compared with 57 out of 60 patients (95%) of Group A and 51 out of 59 (86.4%) of Group B (P<.001). CONCLUSIONS: This study suggests that administration of M. chamomilla L., M. officinalis L. and tyndallized L. acidophilus (HA122) and L. reuteri DSM 17938 are significantly more effective than simethicone in IC. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT02708238.

Paediatric ulcerative colitis surgery: Italian survey.

BACKGROUND AND AIMS: Recent epidemiological studies showed an increase in ulcerative colitis among children, especially in its aggressive form, requiring surgical treatment. Although medical therapeutic strategies are standardized, there is still no consensus regarding indications, timing and kind of surgery. This study aimed to define the surgical management of paediatric ulcerative colitis and describe attitudes to it among paediatric surgeons. METHODS: This was a retrospective cohort study. All national gastroenterology units were invited to participate. From January 2009 to December 2013, data on paediatric patients diagnosed with ulcerative colitis that required surgery were collected. RESULTS: Seven units participated in the study. Seventy-one colectomies were performed (77.3% laparoscopically). Main surgical indications were a severe ulcerative colitis attack (33.8%) and no response to medical therapies (56.3%). A three-stage strategy was chosen in 71% of cases. Straight anastomosis was performed in 14% and J-pouch anastomosis in 86% of cases. A reconstructive laparoscopic approach was used in 58% of patients. Ileo-anal anastomosis was performed by the Knight-Griffen technique in 85.4% and by the pull-through technique in 9.1% of patients. Complications after colectomy, after reconstruction and after stoma closure were reported in 12.7, 19.3 and 35% of cases, respectively. CONCLUSIONS: This study shows that there is general consensus regarding indications for surgery. The ideal surgical technique remains under debate. Laparoscopy is a procedure widely adopted for colectomy but its use in reconstructive surgery remains limited. Longer follow-up must be planned to define the quality of life of these patients.

Slowly fading super-luminous supernovae that are not pair-instability explosions.

Super-luminous supernovae that radiate more than 10(44) ergs per second at their peak luminosity have recently been discovered in faint galaxies at redshifts of 0.1-4. Some evolve slowly, resembling models of 'pair-instability' supernovae. Such models involve stars with original masses 140-260 times that of the Sun that now have carbon-oxygen cores of 65-130 solar masses. In these stars, the photons that prevent gravitational collapse are converted to electron-positron pairs, causing rapid contraction and thermonuclear explosions. Many solar masses of (56)Ni are synthesized; this isotope decays to (56)Fe via (56)Co, powering bright light curves. Such massive progenitors are expected to have formed from metal-poor gas in the early Universe. Recently, supernova 2007bi in a galaxy at redshift 0.127 (about 12 billion years after the Big Bang) with a metallicity one-third that of the Sun was observed to look like a fading pair-instability supernova. Here we report observations of two slow-to-fade super-luminous supernovae that show relatively fast rise times and blue colours, which are incompatible with pair-instability models. Their late-time light-curve and spectral similarities to supernova 2007bi call the nature of that event into question. Our early spectra closely resemble typical fast-declining super-luminous supernovae, which are not powered by radioactivity. Modelling our observations with 10-16 solar masses of magnetar-energized ejecta demonstrates the possibility of a common explosion mechanism. The lack of unambiguous nearby pair-instability events suggests that their local rate of occurrence is less than 6 × 10(-6) times that of the core-collapse rate.

A low-energy core-collapse supernova without a hydrogen envelope.

The final fate of massive stars depends on many factors. Theory suggests that some with initial masses greater than 25 to 30 solar masses end up as Wolf-Rayet stars, which are deficient in hydrogen in their outer layers because of mass loss through strong stellar winds. The most massive of these stars have cores which may form a black hole and theory predicts that the resulting explosion of some of them produces ejecta of low kinetic energy, a faint optical luminosity and a small mass fraction of radioactive nickel. An alternative origin for low-energy supernovae is the collapse of the oxygen-neon core of a star of 7-9 solar masses. No weak, hydrogen-deficient, core-collapse supernovae have hitherto been seen. Here we report that SN 2008ha is a faint hydrogen-poor supernova. We propose that other similar events have been observed but have been misclassified as peculiar thermonuclear supernovae (sometimes labelled SN 2002cx-like events). This discovery could link these faint supernovae to some long-duration gamma-ray bursts, because extremely faint, hydrogen-stripped core-collapse supernovae have been proposed to produce such long gamma-ray bursts, the afterglows of which do not show evidence of associated supernovae.

A very faint core-collapse supernova in M85.

An anomalous transient in the early Hubble-type (S0) galaxy Messier 85 (M85) in the Virgo cluster was discovered by Kulkarni et al. on 7 January 2006 that had very low luminosity (peak absolute R-band magnitude M(R) of about -12) that was constant over more than 80 days, red colour and narrow spectral lines, which seem inconsistent with those observed in any known class of transient events. Kulkarni et al. suggest an exotic stellar merger as the possible origin. An alternative explanation is that the transient in M85 was a type II-plateau supernova of extremely low luminosity, exploding in a lenticular galaxy with residual star-forming activity. This intriguing transient might be the faintest supernova that has ever been discovered.

A giant outburst two years before the core-collapse of a massive star.

The death of massive stars produces a variety of supernovae, which are linked to the structure of the exploding stars. The detection of several precursor stars of type II supernovae has been reported (see, for example, ref. 3), but we do not yet have direct information on the progenitors of the hydrogen-deficient type Ib and Ic supernovae. Here we report that the peculiar type Ib supernova SN 2006jc is spatially coincident with a bright optical transient that occurred in 2004. Spectroscopic and photometric monitoring of the supernova leads us to suggest that the progenitor was a carbon-oxygen Wolf-Rayet star embedded within a helium-rich circumstellar medium. There are different possible explanations for this pre-explosion transient. It appears similar to the giant outbursts of luminous blue variable stars (LBVs) of 60-100 solar masses, but the progenitor of SN 2006jc was helium- and hydrogen-deficient (unlike LBVs). An LBV-like outburst of a Wolf-Rayet star could be invoked, but this would be the first observational evidence of such a phenomenon. Alternatively, a massive binary system composed of an LBV that erupted in 2004, and a Wolf-Rayet star exploding as SN 2006jc, could explain the observations.

Adding consumer-providers to intensive case management: does it improve outcome?

OBJECTIVE: Over the past decade, there has been increasing interest in the employment of mental health consumers in various roles as providers of services. Although integration of consumers into case management services has been studied, the roles of consumers have been poorly defined and the benefits have not been established. The goal of this study was to evaluate whether consumers enhance case management outcome through the provision of social support. METHODS: This study compared consumer-assisted and non-consumer-assisted case management with standard clinic-based care. The consumer role focused on the development of social support by using peer staff who matched the profile of participants. A total of 203 clients with severe and persistent mental illness were randomly assigned to one of the three conditions and followed for 12 months. RESULTS: All three programs yielded the same general pattern of improvement over time for symptoms, health care satisfaction, and quality of life. Clients in the three programs also showed similar but small changes in measures of social network behavior. Consumer-assisted case management was unique in its use of peer-organized activities. Non-consumer-assisted case management made greater use of individual contacts with professional staff. Standard clinic-based care relied more on group and on individual therapy. Despite these variations in the pattern of services over a 12-month period, no one program emerged as categorically superior to the others. CONCLUSIONS: Although more research is needed to determine optimal roles for consumers in mental health service delivery, a randomized trial found no evidence that the presence of consumers enhances case management outcome.

Direct coronary stenting versus stenting with balloon pre-dilation: incidence of enzyme release and follow-up results of a multicentre, prospective, randomized study. The CK and Troponin I Estimation in direct STenting (CK TEST) trial.

AIM: The aim of this study was to assess the safety of direct coronary stenting, its influence on costs, duration of the procedure, radiation exposure, clinical outcome and the incidence of periprocedural myocardial damage as assessed by enzyme release determination. METHODS: We randomized 103 patients (109 lesions) to direct stent implant or stent implant following balloon predilatation. Patients with heavily calcified lesions, bifurcations, total occlusions, left main lesions and very tortuous vessels were excluded. Three samples of blood were drawn; before, 12 and 24 h after the procedure and total CK, CK MB mass and troponin I determination was carried out in a single centralized laboratory. RESULTS: Direct stenting was successful in 62/62 lesions (100%). No single loss or embolization of the stent occurred. All stents in the group with predilatation were effectively deployed. The immediate post procedure angiographic results were similar with both techniques. Contrast media consumption and procedural time were significantly lower in direct stenting (150+/-82 cc and 30+/-13 min) than in pre-dilated stenting (184+/-85 cc and 36+/-14 min) (P=0.04 and P=0.036 respectively) while fluoroscopy time was similar (9.1+/-12 vs 9.19+/-15 min, P=0.97). The incidence of enzyme release was similar in the groups with only three non Q MI all in the pre-dilated group (P=0.149). Any elevation of CK MB and troponin I occurred in 7% of direct stent vs 12% of pre-dilated group (P=0.66), isolated troponin I elevation in 21% of both groups. Major adverse cardiac events during hospitalization were 0 in direct and 3 in pre-dilated stenting (P=0.66), but there were no significant differences at follow-up at 1, 6 and 12 months between the 2 groups (target lesion revascularization at 12 months 11 vs 14% in the 2 groups respectively). CONCLUSION: Direct stenting is as safe as pre-dilated stenting in selected coronary lesions. Acute results and myocardial damage as assessed by enzyme release determination are similar, but procedural costs (as measured by resource consumption) and duration of the procedure are lower in direct stenting. Overall success rate and mid-term clinical outcome are similar with both techniques.

Circulating nitric oxide in women affected by weight loss amenorrhea during pulsatile gonadotropin-releasing hormone therapy.

No specific markers of the severity or prognosis of hypothalamic-pituitary-gonadal axis disturbances associated with weight loss amenorrhea (WLA) are currently available. Circulating nitric oxide (NO), which is involved in the control of the reproductive function in women and is correlated with body mass index (BMI), at least in over-weight and obese subjects, might be a marker of the severity and/or progression of WLA. To test this hypothesis, we studied circulating NO levels in 11 women (age 27.1 +/- 1.59 yr) affected by WLA for 5.1 +/- 1.0 yr; in all patients hormonal therapy had been discontinued 10.0 +/- 3.15 months earlier. NO, determined by measuring its stable catabolite nitrite/nitrates (NOx), was compared with some clinical parameters and sex hormone levels. Subsequently, changes in NOx during pulsatile GnRH therapy (120 ng/kg bw sc every 120 min) were compared with the clinical and hormonal data. Fifteen normal women (27.3 +/- 1.6 yr) served as a control group. NOx was significantly lower (p<0.01) in WLA (8.8 +/- 2.0 micromol/l) than in control (18.7 +/- 2.5 micromol/l) subjects. No correlation between NOx and clinical parameters was noted in either WLA or control subjects. As a result of GnRH therapy, ovulatory cycles reappeared in 91% of WLA women. During the 1st cycle, periovulatory 17beta-estradiol levels were 110% higher than those noted in controls. During the 2nd cycle, NOx showed a slight increase in the follicular phase (+12% vs 1st cycle) followed by a drop during the luteal phase (-40% from the follicular phase); indeed, at that time, NOx correlated negatively with progesterone in both WLA (rS -0.32, p<0.05) and control (rS -0.48, p<0.05) subjects. NOx correlated with BMI at the time of the 2nd cycle (rS 0.71, p<0.05). In conclusion, this study shows that in WLA patients: 1) NO is low, as in other conditions of chronic anovulation; 2) it does not correlate with clinical data; 3) it takes longer than sex steroids to increase and show normal-like fluctuations; 4) its fluctuations are restored earlier in patients with greater BMI.

Recombinant human TSH changes the multidisciplinary approach to patients with differentiated thyroid carcinoma. Two-year experience.

BACKGROUND: Recombinant human TSH (rhTSH) is available for monitoring differentiated thyroid carcinoma. rhTSH testing modifies the guidelines for this disease. METHODS: A 2-year experience with rhTSH on 27 consecutive patients with papillary cancer is reported. The aim of the study was to evaluate the sensitivity and specificity of thyroglobulin (Tg) after rhTSH in detecting residual thyroid cancer after primary therapies. Sensitivity and specificity of rhTSH testing were also compared with neck ultrasound (US) and whole-body scan (WBS). Favourable results were regarded as: Tg levels <1 microg/L after rhTSH, no US image indicative of thyroid tissue or suspect neck nodes, and negative WBS after (131)I and (99m)Tc-MIBI. RESULTS: Side effects were mild. Unfavourable baseline Tg levels were noted in 15% of patients with local or metastatic disease. After rhTSH testing, unfavourable Tg levels were noted in a further 17% of patients. After 12-24 months, Tg levels on rhTSH re-testing were favourable in 14 out of 17 patients evaluated and indicative of no disease progression in 1; in 2, they were still indicative of an unsatisfactory effect of further radioiodine therapy. No significant increase in a subunit (alphaSU) was noted after rhTSH administration. Sera from patients with hypothyroidism or collected on the day of TSH peak after rhTSH, showed isoform profiles of TSH (and alphaSU) similar to those found after focusing rhTSH. Agreement between rhTSH testing and neck US was found in 85% of patients. Agreement among rhTSH, neck US and (131)I and (99m)Tc-MIBI WBS was found in 46% of subjects. The specificity of rhTSH testing, neck US, (131)I and (99m)Tc-MIBI WBS was 95%, 84%, 89% and 53%, while sensitivity was 100%, 87%, 40% and 71%, respectively. CONCLUSIONS: Our data show that full bioactivity of TSH after rhTSH is indirectly suggested by the negligible increase in alphaSU after rhTSH and the similar pattern of TSH isoforms after rhTSH and hypothyroidism. Neck US is the most sensitive imaging technique in detecting local or neck node recurrence of the disease, while (99m)Tc-MIBI WBS is the least specific. After primary treatments for papillary thyroid carcinoma, rhTSH testing under L-T4 therapy and neck US may be regarded as first-line evaluations. Under L-T4 regimen, Tg levels lower than 1 microg/L after rhTSH testing seem to be the best index of normality on follow-up in patients with a history of thyroid papillary carcinoma. In these patients, diagnostic (131)I WBS seems to be unnecessary.

Circulating nitric oxide levels increase after anti-androgen treatment in male-to-female transsexuals.

Circulating nitric oxide is produced by the vascular endothelium under the influence of the sex steroid milieu and shows gender difference. Since data on hormonal manipulation in males are scant, the present study was designed to evaluate nitric oxide levels before and after anti-androgen treatment in young male-to-female (MF) transsexuals. Fifteen MF transsexuals aged 23.7 +/- 1.3 yr, with normal testicular volume and normal body mass index were studied. Twenty adult males aged 28.2 +/- 2.4 yr served as controls. A low nitrate diet was administered to all subjects throughout the study, starting 15 days before the beginning. Blood samples were drawn from all subjects on day 0; flutamide 750 mg/day was then administered to transsexuals for 30 days, and another sample was taken on day 30. In all subjects the concentration of nitrite plus nitrate (NOx), two stable compounds into which nitric oxide spontaneously decomposes, was determined; also total testosterone (T) and free testosterone (fT), 17(beta)estradiol (E2), SHBG, delta4-androstenedione (A), DHEAS, 17-hydroxy-progesterone (OHP), LH, FSH and PRL were assayed. All hormones determined in controls and transsexuals were comparable at the beginning of the study. NOx was also comparable in controls (11.0 +/- 1.0 microM/l) and transsexuals (11.1 +/- 1.2 microM/l) and did not significantly correlate with any of the hormones assayed. After 30 days of flutamide administration, LH, T, fT, A and E2 increased; DHEAS decreased, while FSH, SHBG and PRL were unchanged; NOx rose significantly (18.7 +/- 1.7 microM/l; p < 0.05), and its percentage increase with respect to pre-treatment levels correlated with that of E2 (R = 0.77; p < 0.01). Healthy males and MF transsexuals do not differ in terms of sex hormones and NOx levels. In neither group is NOx significantly correlated to any sex hormone assayed. Treatment with flutamide in MF transsexuals elicits an increase in androgens, which are not biologically active because of the androgen receptor blockade, and an increase in the estrogenic milieu, which correlates with the increase in NOx.

Circulating nitric oxide is modulated by recombinant human TSH administration during monitoring of thyroid cancer remnant.

During the administration of recombinant human TSH (rhTSH) to monitor differentiated thyroid carcinoma, mild side effects, such as nausea and headaches, often occur. The origin of these is not clear. Since changes in TSH and thyroid hormones can modulate some endothelial-derived factors, we aimed at testing whether rhTSH administration induces changes in nitric oxide. We studied 25 patients (56.6+/-12.6 yr) who had undergone thyroidectomy followed by ablative radioiodine for papillary thyroid cancer and who were under follow-up. While L-thyroxine therapy continued, thyroglobulin (Tg), TSH, free-T3, free-T4 and nitrite-plus-nitrate (NOx) concentrations were evaluated before and after rhTSH administration (0.9 mg i.m. on 2 consecutive days). Mean TSH showed a huge increase from baseline (0.1+/-0.0 mIU/l) to day 3 (216.3+/-17.5 mIU/l, p<0.001), which was not accompanied by changes in thyroid hormones. Mean baseline NOx levels were 12.6+/-1.2 micromoles/l and showed a significant increase on day 3 (20.1+/-1.2 micromoles/l, p<0.05 vs day 0), followed by progressive reduction from day 6 (18.1+/-2.8 micromoles/l) to day 9 (10.6+/-1.3 micromoles/l, p<0.05 vs day 0). There was a significant (p=0.04) correlation between the percentage increase in TSH and the percentage increase in NOx. On the other hand, increase in TSH did not correlate with the percentage decrease in NOx from day 6 to day 9. No correlation was noted between the increase in TSH or NOx and the occurrence or severity of the symptoms. Our study shows that, during rhTSH testing, circulating nitric oxide increases. This endothelial-derived factor might, in turn, mediate the occurrence of vasomotor headache and nausea in some particularly susceptible patients.

Circulating nitric oxide changes throughout the menstrual cycle in healthy women and women affected by pathological hyperprolactinemia on dopamine agonist therapy.

The aim of the study was to evaluate circulating nitric oxide (NO) levels throughout ovulatory cycles in healthy women and women under long-term treatment with dopamine agonists. Fifty women (aged 32.5 +/- 1.2 years) affected by pathological hyperprolactinemia (prolactin (PRL)-secreting microadenoma, 63%; idiopathic, 19%; 'empty sella', 12%; and PRL-secreting macroadenoma, 6%) and on dopamine-agonist therapy (range 1-10 years) were studied; 37 healthy women (aged 30.4 +/- 1.4 years) served as a control group. Blood samples were collected on days 7, 14 and 21 of the menstrual cycle in order to assay NO, PRL, 17 beta-estradiol and progesterone. In all subjects, ovulatory cycles were recorded. PRL levels were comparable between the two groups and significantly rose during the luteal phase. NO levels recorded throughout the menstrual cycles of healthy controls were significantly higher than those recorded in subjects treated with dopamine-agonist; NO levels in the latter were no different from those recorded in non-treated, non-ovulatory hyperprolactinemic women. However, in both healthy controls and dopamine-agonist-treated women, NO was negatively correlated with progesterone concentration and significantly reduced on day 21. In dopamine-treated patients, NO levels did not correlate with the dose or the duration of dopamine-agonist therapy. We conclude that, in our hyperprolactinemic women on therapy, physiological NO secretion is not fully restored, despite restoration of ovulatory cycles by dopamine-agonist therapy.

Perception of sports photographs: a multidimensional scaling analysis.

Some sports photographs are remarkable for how animate they appear, whereas others seem particularly static or frozen. To explore the aspects of still photographs that might produce a sense of action, 34 observers viewed all possible pairs of 14 previously published images depicting sports figures in action and were asked to judge their similarity under two conditions, image-focus (how similar are the images) or movement-focus (how similar is the type of movement). A separate group of observers also rated each image on eight scales. Multidimensional scaling analyses suggested that in the image-focus condition, subjects tended to organize their judgments around three general dimensions, e.g., on-ground versus off-ground, while in the movement-focus condition the subjects were more likely to cluster the images along the lines of the particular activity, throwing, running, or jumping. We discuss the problem of movement depiction in sports photographs and make suggestions for research on the effects of facial expressions, muscular strain, and amount of limb extension.

Changes in binding of iodomelatonin to membranes of Leydig cells and steroidogenesis after prolonged in vitro exposure to melatonin.

The aim of the present study was to investigate the effects of prolonged exposure to melatonin (MLT) on the binding of iodomelatonin to membranes of rat Leydig cells and the subsequent modulation of testosterone and cyclic adenocine monophosphate (cAMP) secretion from these cells by MLT itself. Leydig cells were Percoll-purified from adult rats and cultured in vitro with MLT (1--100 nmol/L) for 16 h. Binding assays with 2(125I)iodomelatonin were then performed; moreover, testosterone and cAMP secretion during an acute challenge with lutenizing hormone (LH) (20 mIU/mL for 3 h) was assayed by RIA. As a result of prolonged MLT administration, a decrease in maximum binding density (Bmax) and equilibrium dissociation constant (Kd) of the binding of 2(125I)iodomelatonin to purified cell membranes was noted. Higher testosterone and cAMP secretion during LH challenge were recorded in cells pre-incubated with MLT; notwithstanding, the inhibitory effect of acutely administered MLT on LH-challenged secretions was not only retained but also reinforced, as the IC50 was 30% lower in cells pre-treated with the higher concentration of MLT (100 nM). Cycloheximide administration (10 microg/mL for 16 h) did not prevent hyper-sensitization to LH challenge or to acute MLT administration on LH challenge. Pertussis toxin (180 ng/mL for 16 h) prevented hyper-sensitization to LH, but not to acutely administered MLT. Forskolin (10 nmol/L) administration abolished either phenomena. In conclusion, prolonged exposure to MLT modulates the secretion of testosterone by cultured rat Leydig cells. Although MLT receptors were reduced, hyper-sensitization to LH challenge and to acutely administered MLT on LH challenge were observed with the higher concentration of MLT. Reduction in intracellular cAMP as a result of prolonged administration of MLT, could be the primary cause of both phenomena. On the one hand, reduced cAMP could start re-arrangement of the G-proteins and thus LH-dependent adenylate cyclase sensitization. On the other hand, reduced cAMP could render the Leydig cells more responsive to MLT itself through a mechanism which does not involve G-protein re-arrangement.