Do current-density nonlinearities cut off the glass transition?

Extended mode coupling theories for dense fluids predict that nonlinear current-density couplings cut off the singular `ideal glass transition', present in the standard mode coupling theory where such couplings are ignored. We suggest here that, rather than allowing for activated processes as sometimes supposed, contributions from current-density couplings are always negligible close to a glass transition. We discuss in schematic terms how activated processes can nonetheless cut off the transition, by causing the memory function to become linear in correlators at late times.Comment: 4 page

Pteropods are excellent recorders of surface temperature and carbonate ion concentration

Pteropods are among the first responders to ocean acidification and warming, but have not yet been widely explored as carriers of marine paleoenvironmental signals. In order to characterize the stable isotopic composition of aragonitic pteropod shells and their variation in response to climate change parameters, such as seawater temperature, pteropod shells (Heliconoides inflatus) were collected along a latitudinal transect in the Atlantic Ocean (31° N to 38° S). Comparison of shell oxygen isotopic composition to depth changes in the calculated aragonite equilibrium oxygen isotope values implies shallow calcification depths for H. inflatus (75 m). This species is therefore a good potential proxy carrier for past variations in surface ocean properties. Furthermore, we identified pteropod shells to be excellent recorders of climate change, as carbonate ion concentration and temperature in the upper water column have dominant influences on pteropod shell carbon and oxygen isotopic composition. These results, in combination with a broad distribution and high abundance, make the pteropod species studied here, H. inflatus, a promising new proxy carrier in paleoceanography

Dilatancy, Jamming, and the Physics of Granulation

Granulation is a process whereby a dense colloidal suspension is converted into pasty granules (surrounded by air) by application of shear. Central to the stability of the granules is the capillary force arising from the interfacial tension between solvent and air. This force appears capable of maintaining a solvent granule in a jammed solid state, under conditions where the same amount of solvent and colloid could also exist as a flowable droplet. We argue that in the early stages of granulation the physics of dilatancy, which requires that a powder expand on shearing, is converted by capillary forces into the physics of arrest. Using a schematic model of colloidal arrest under stress, we speculate upon various jamming and granulation scenarios. Some preliminary experimental results on aspects of granulation in hard-sphere colloidal suspensions are also reported.Comment: Original article intended for J Phys Cond Mat special issue on Granular Materials (M Nicodemi, Ed.

Evidence for the validity of Protatlanta sculpta (Gastropoda: Pterotracheoidea)

The genus Protatlanta is thought to be monotypic and is part of the Atlantidae, a family of shelled heteropods. These microscopic planktonic gastropods are poorly known, although research on their ecology is now increasing in response to concerns about the effects of ocean acidification on calcareous plankton. A correctly implemented taxonomy of the Atlantidae is fundamental to this progressing field of research and it requires much attention, particularly using integrated molecular and morphological techniques. Here we use DNA barcoding, shell morphology and biogeography to show that the genus Protatlanta includes at least two valid species in the Atlantic Ocean. Protatlanta souleyeti and Protatlanta sculpta were found to be separate species, with different shell morphology and separated by a K2P genetic distance of 19% sequence divergence at the Cytochrome Oxidase 1 gene. This evidence supports the revival of the species name P. sculpta, which was described by Issel in 1911, but has not been recognised as a valid species since 1915

Excellent agreement between genetic and hydrogen breath tests for lactase deficiency and the role of extended symptom assessment

Clinical manifestations of lactase (LCT) deficiency include intestinal and extra-intestinal symptoms. Lactose hydrogen breath test (H2-BT) is considered the gold standard to evaluate LCT deficiency (LD). Recently, the single-nucleotide polymorphism C/T−13910 has been associated with LD. The objectives of the present study were to evaluate the agreement between genetic testing of LCT C/T−13910 and lactose H2-BT, and the diagnostic value of extended symptom assessment. Of the 201 patients included in the study, 194 (139 females; mean age 38, range 17-79 years, and 55 males, mean age 38, range 18-68 years) patients with clinical suspicion of LD underwent a 3-4h H2-BT and genetic testing for LCT C/T−13910. Patients rated five intestinal and four extra-intestinal symptoms during the H2-BT and then at home for the following 48h. Declaring H2-BT as the gold standard, the CC−13910 genotype had a sensitivity of 97% and a specificity of 95% with a κ of 0·9 in diagnosing LCT deficiency. Patients with LD had more intense intestinal symptoms 4h following the lactose challenge included in the H2-BT. We found no difference in the intensity of extra-intestinal symptoms between patients with and without LD. Symptom assessment yielded differences for intestinal symptoms abdominal pain, bloating, borborygmi and diarrhoea between 120min and 4h after oral lactose challenge. Extra-intestinal symptoms (dizziness, headache and myalgia) and extension of symptom assessment up to 48h did not consistently show different results. In conclusion, genetic testing has an excellent agreement with the standard lactose H2-BT, and it may replace breath testing for the diagnosis of LD. Extended symptom scores and assessment of extra-intestinal symptoms have limited diagnostic value in the evaluation of L

The Role of Perceived Control and Cardiac Function among Individuals with Binge Eating Symptomatology

The central aim of this study was to investigate the predictive role of perceived control in binge eating severity, mood reactivity, and possible concomitants with reduced cardiovascular function as measured by high frequency heart rate variability (HF-HRV/RSA). Participants (N = 75) included normal to overweight men and women who completed self-report measures assessing perceived control, binge eating severity, perceived stress, negative affect, and depressive symptom severity prior to a structured clinical interview and second experimental laboratory session. During this second experimental lab session, noninvasive electrical sensors were placed for physiological recordings to measure fluctuations in HF-HRV/RSA in participants randomized to a negative or neutral mood induction task. In addition to physiological data, participants completed self-report measures of mood and stress during baseline assessment, post-mood induction, and following a recovery period. Results indicated that perceived control was predictive of binge eating severity such that higher self-reported perceived control was associated with less severe binge eating symptoms. This association was significantly mediated by perceived stress and depressive symptoms, such that those with greater perceived control also experienced less perceived stress and reduced depressive symptoms, which then significantly predicted less binge eating severity. These associations remained significant across sex and history of major depressive disorder (MDD). No significant associations were observed between perceived control, binge eating severity, and mood, stress, or HF-HRV/RSA reactivity. Results from the current investigation suggest that perceived control may buffer individuals from stress and depressive symptoms and predict less severe binge eating symptoms. Importantly, perceived control is an adaptive variable that can be modified through experience (Surtees et al., 2010). In line with prior research, which suggests that perceived control may be a malleable treatment target and predictive of positive outcomes following CBT for anxiety and mood disorders (Doering et al., 2015), the current results propose that perceived control may be a universal treatment target across various binge eating populations

Excellent agreement between genetic and hydrogen breath tests for lactase deficiency and the role of extended symptom assessment

Clinical manifestations of lactase (LCT) deficiency include intestinal and extra-intestinal symptoms. Lactose hydrogen breath test (H2-BT) is considered the gold standard to evaluate LCT deficiency (LD). Recently, the single-nucleotide polymorphism C/T(-13910) has been associated with LD. The objectives of the present study were to evaluate the agreement between genetic testing of LCT C/T(-13910) and lactose H2-BT, and the diagnostic value of extended symptom assessment. Of the 201 patients included in the study, 194 (139 females; mean age 38, range 17-79 years, and 55 males, mean age 38, range 18-68 years) patients with clinical suspicion of LD underwent a 3-4 h H2-BT and genetic testing for LCT C/T(-13910). Patients rated five intestinal and four extra-intestinal symptoms during the H2-BT and then at home for the following 48 h. Declaring H2-BT as the gold standard, the CC(-13910) genotype had a sensitivity of 97% and a specificity of 95% with a κ of 0.9 in diagnosing LCT deficiency. Patients with LD had more intense intestinal symptoms 4 h following the lactose challenge included in the H2-BT. We found no difference in the intensity of extra-intestinal symptoms between patients with and without LD. Symptom assessment yielded differences for intestinal symptoms abdominal pain, bloating, borborygmi and diarrhoea between 120 min and 4 h after oral lactose challenge. Extra-intestinal symptoms (dizziness, headache and myalgia) and extension of symptom assessment up to 48 h did not consistently show different results. In conclusion, genetic testing has an excellent agreement with the standard lactose H2-BT, and it may replace breath testing for the diagnosis of LD. Extended symptom scores and assessment of extra-intestinal symptoms have limited diagnostic value in the evaluation of LD

Brain glucose utilization in systemic lupus erythematosus with neuropsychiatric symptoms: A controlled positron emission tomography study

In contrast to morphological imaging [such as magnetic resonance imaging (MRI) or computed tomography], functional imaging may be of advantage in the detection of brain abnormalities in cases of neuropsychiatric systemic lupus erythematosus (SLE). Therefore, we studied 13 patients (aged 40±14 years, 11 female, 2 male) with neuropsychiatric SLE who met four of the American Rheumatism Association criteria for the classification of SLE. Ten clinically and neurologically healthy volunteers served as controls (aged 40±12 years, 5 female, 5 male). Both groups were investigated using fluorine-18-labelled fluorodeoxyglucose brain positron emission tomography (PET) and cranial MRI. The normal controls and 11 of the 13 patients showed normal MRI scans. However, PET scan was abnormal in all 13 SLE patients. Significant group-to-group differences in the glucose metabolic index (GMI=region of interest uptake/global uptake at the level of the basal ganglia and thalamus) were found in the parieto-occipital region on both sides: the GMI of the parieto-occipital region on the right side was 0.922±0.045 in patients and 1.066±0.081 in controls (P<0.0001, Mann WhitneyU test), while on the left side it was 0.892±0.060 in patients and 1.034±0.051 in controls (P=0.0002). Parietooccipital hypometabolism is a conspicuous finding in mainly MRI-negative neuropsychiatric SLE. As the parieto-occipital region is located at the boundary of blood supply of all three major arteries, it could be the most vulnerable zone of the cerebrum and may be affected at an early stage of the cerebrovascular diseas

DOTATOC: A powerful new tool for receptor-mediated radionuclide therapy

This study presents the first successful use of a peptidic vector, DOTATOC, labelled with the β-emitting radioisotope yttrium-90, for the treatment of a patient with somatostatin receptor-positive abdominal metastases of a neuroendocrine carcinoma of unknown localization. Tumour response and symptomatic relief were achieved. In addition, the new substance DOTA-TOC was labelled with the diagnostic chemical analogue indium-111 and studied in three patients with histopathologically verified neuroendocrine abdominal tumours for its diagnostic sensitivity and compared with the commercially available OctreoScan. In all patients the kidney-to-tumour uptake ratio (in counts per pixel) was on average 1.9-fold lower with111In-DOTATOC than with OctreoScan. DOTATOC could be a potential new diagnostic and therapeutic agent in the management of neuroendocrine tumour

Inherent-Structure Dynamics and Diffusion in Liquids

The self-diffusion constant D is expressed in terms of transitions among the local minima of the potential (inherent structure, IS) and their correlations. The formulae are evaluated and tested against simulation in the supercooled, unit-density Lennard-Jones liquid. The approximation of uncorrelated IS-transition (IST) vectors, D_{0}, greatly exceeds D in the upper temperature range, but merges with simulation at reduced T ~ 0.50. Since uncorrelated IST are associated with a hopping mechanism, the condition D ~ D_{0} provides a new way to identify the crossover to hopping. The results suggest that theories of diffusion in deeply supercooled liquids may be based on weakly correlated IST.Comment: submitted to PR