Hyperstoichiometric Interaction Between Silver and Mercury at the Nanoscale**

Breaking through the stoichiometry barrier: As the diameter of silver particles is decreased below a critical size of 32?nm, the molar ratio of aqueous HgII to Ag0 drastically increases beyond the conventional Hg/Ag ratio of 0.5:1, leading to hyperstoichiometry with a maximum ratio of 1.125:1 (see figure). Therein, around 99?% of the initial silver is retained to rapidly form a solid amalgam with reduced mercury

Neolithic Mitochondrial Haplogroup H Genomes and the Genetic Origins of Europeans

Haplogroup H dominates present-day Western European mitochondrial DNA variability (\u3e40%), yet was less common (~19%) among Early Neolithic farmers (~5450 BC) and virtually absent in Mesolithic hunter-gatherers. Here we investigate this major component of the maternal population history of modern Europeans and sequence 39 complete haplogroup H mitochondrial genomes from ancient human remains. We then compare this ‘real-time’ genetic data with cultural changes taking place between the Early Neolithic (~5450 BC) and Bronze Age (~2200 BC) in Central Europe. Our results reveal that the current diversity and distribution of haplogroup H were largely established by the Mid Neolithic (~4000 BC), but with substantial genetic contributions from subsequent pan-European cultures such as the Bell Beakers expanding out of Iberia in the Late Neolithic (~2800 BC). Dated haplogroup H genomes allow us to reconstruct the recent evolutionary history of haplogroup H and reveal a mutation rate 45% higher than current estimates for human mitochondria

Urinary pH in panic disorder

Urinary pH was evaluated in panic disorder (PD) patients compared with both psychiatric and healthy control subjects. Fourteen PD patients, eight major depressive disorder (MDD) patients, and 14 healthy control (HC) subjects were examined. All patients were drug-free and met DSM-IV diagnostic criteria. The PD patients had lower urinary pH and higher levels of anxiety than both MDD and HC subjects. Additionally, urinary p inversely correlated with anxiety levels. Although preliminary, these findings suggest that PD patients have lower urinary pH than MDD and HC subjects. Future studies that simultaneously examine both urinary and blood pH in larger numbers of PD patients and patients with other anxiety disorders, before and after treatment, need to be conducted. © 2005 Elsevier Ireland Ltd. All rights reserved.134219920

Urinary pH in panic disorder

Urinary pH was evaluated in panic disorder (PD) patients compared with both psychiatric and healthy control subjects. Fourteen PD patients, eight major depressive disorder (MDD) patients, and 14 healthy control (HC) subjects were examined. All patients were drug-free and met DSM-IV diagnostic criteria. the PD patients had lower urinary pH and higher levels of anxiety than both MDD and HC subjects. Additionally, urinary p inversely correlated with anxiety levels. Although preliminary, these findings suggest that PD patients have lower urinary pH than MDD and HC subjects. Future studies that simultaneously examine both urinary and blood pH in larger numbers of PD patients and patients with other anxiety disorders, before and after treatment, need to be conducted. © 2005 Elsevier Ireland Ltd. All rights reserved.Universidade Federal de São Paulo, Dept Psychiat, BR-04026001 São Paulo, BrazilState Univ Campinas, Dept Med Psychol & Psychiat, Campinas, SP, BrazilWayne State Univ, Dept Psychiat & Behav Neurosci, Detroit, MI 48202 USAUniversidade Federal de São Paulo, Dept Psychiat, BR-04026001 São Paulo, BrazilWeb of Scienc

Measurement of the orbitofrontal cortex: a validation study of a new method

The orbital frontal cortex (OFC) plays a critical role in the pathophysiology of several neuropsychiatric disorders. Few morphometric neuroimaging studies have examined the OFC using different methodologies and have reported discrepant values. Substantial variability in gyri and sulci across individuals as well as unclear landmarks underline the difficulties in obtaining accurate and reliable measurements. We propose a new geometrical method for measuring the OFC taking into account individual brain variability. The OFC was defined by using the intercommissural line and the inferior edge of the frontal lobe as the main landmarks. The medial and lateral subdivisions of OFC were also separately measured using the olfactory sulcus as the boundary to distinguish between them. After resampling and refitting, 10 scans were independently traced by two trained researchers using BRAINS software. Talairach coordinates were identified on each scan from the OFC and surrounding adjacent brain regions to assess the validity of this method. Brain regions were assigned using Talairach Daemon system. OFC volumes were comparable with those previously reported. Sensitivity and specificity for OFC gray matter were 87.6 and 84.8%. respectively. Intraclass coefficients (ICCs) for gray, white, and total OFC were 0.995, 0.994, and 0.997, respectively. ICCs for OFC medial and lateral subdivisions ranged between 0.996 and 0.998. This method appears to be a valid method for measuring the OFC with excellent reliability. This uncomplicated approach is easy to apply and has the potential to be a valuable alternative to the previously published methods. (C) 2003 Elsevier Science (USA). All rights reserved.19366567

Elevated thalamic and prefrontal regional cerebral blood flow in obsessive-compulsive disorder: a SPECT study

Functional neuroimaging studies have pointed to a possible role of cerebral circuits involving the prefrontal and anterior cingulate cortices, the striatum, and thalamus in the pathophysiology of obsessive-compulsive disorder (OCD). Regional cerebral blood flow (rCBF) of 16 drug-free Brazilian patients with OCD and 17 healthy subjects matched for age, gender, handedness and level of education was measured with [99m-Tc] HMPAO single photon emission computed tomography. Analysis of covariance identified four regions of interest with significantly higher rCBF: the right superior and inferior frontal cortex and the right and left thalamus. Positive correlations between symptom severity measured by Clinical Global Impression scores and rCBF were found in the right and left inferior frontal lobes and in the right basal ganglia. Compulsive behavior was inversely correlated with rCBF in the right thalamus, and duration of illness correlated positively with rCBF in the right and left superior frontal lobes and with the right thalamus. The findings of this SPECT study conducted in Brazil are in agreement with prior studies and provide additional support for the involvement of prefrontal-subcortical circuits in the pathophysiology of OCD. Furthermore, the study suggests that similar brain mechanisms appear to be involved cross-culturally. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.123212513

Magnetic resonance imaging study of the orbitofrontal cortex in autism

The orbitofrontal cortex is involved in multiple psychologic functions, such as emotional and cognitive processing, learning, and social behavior. These functions are variably impaired in individuals with autism. The present study examined the size of the orbitofrontal cortex, and its medial and lateral subdivisions, using magnetic resonance imaging (MRI) scans obtained from 40 non-mentally retarded individuals with autism and 41 healthy controls. No differences were observed between the two groups on any of the orbitofrontal cortex measurements. However, when compared with controls, a smaller right lateral orbitofrontal cortex was observed in children and adolescents with autism, whereas a larger right lateral orbitofrontal cortex was found in adult patients. Interestingly, a positive relationship was found in the patient group between circumscribed interests and all orbitofrontal cortex structures. The present study suggests the absence of global volumetric abnormalities in the orbitofrontal cortex in autism and indicates that the functional disturbances in this structure might not be related to anatomic alterations.211086687

Anatomical MRI Study Of Basal Ganglia In Major Depressive Disorder

The basal ganglia form a part of the brain neuroanatomic circuits that may be involved in mood regulation. Decreases in basal ganglia volumes have been previously reported in major depressive disorder patients in comparison to healthy controls. In this study, we measured caudate, putamen, and globus pallidus volumes in 25 patients with major depressive disorder (4 M; age+/-S.D.=41+/-11 years) and 48 healthy controls (29 M; age+/-S.D.=35+/-10 years), using high-resolution magnetic resonance imaging (MRI), in an attempt to replicate prior findings. Unlike most previous studies, we did not find significant differences between patient and control groups in basal ganglia volumetric measures. Nonetheless, there was a significant interaction between diagnosis and cerebral hemisphere, with MDD patients showing decreased asymmetry in globus pallidus volumes in comparison with healthy controls. Furthermore, in the patient group, left putamen volumes correlated inversely with length of illness, and left globus pallidus volume correlated directly with number of prior depressive episodes. These findings suggest that abnormalities in lateralization and possibly neurodegenerative changes in basal ganglia structures participate in the pathophysiology of major depressive disorder