Uniform electron gases

We show that the traditional concept of the uniform electron gas (UEG) --- a homogeneous system of finite density, consisting of an infinite number of electrons in an infinite volume --- is inadequate to model the UEGs that arise in finite systems. We argue that, in general, a UEG is characterized by at least two parameters, \textit{viz.} the usual one-electron density parameter $\rho$ and a new two-electron parameter $\eta$. We outline a systematic strategy to determine a new density functional $E(\rho,\eta)$ across the spectrum of possible $\rho$ and $\eta$ values.Comment: 8 pages, 2 figures, 5 table

Depression rating scales for detection of major depression in people with dementia

This is the protocol for a review and there is no abstract. The objectives are as follows: To identify the accuracy of depression rating scales as screening tools for detecting DpD and compare the diagnostic accuracy of different depression rating scales for detecting MDD among adults with Alzheimer's disease and related forms of dementia. To examine factors that may impact on the accuracy of depression rating scales that are used to diagnose depression. We will examine the reference standard used for verification of DpD, baseline prevalence of DpD in the study population, age of the underlying study population, gender of participants, type of dementia (any-cause dementia versus Alzheimer’s disease), study setting (community or primary care setting, long-term care, tertiary care setting), and study country as potential sources of heterogeneity. We will also evaluate the effects of using different cut-points of individual depression rating scales on the diagnostic accuracy of the scales

A mathematical and computational review of Hartree-Fock SCF methods in Quantum Chemistry

We present here a review of the fundamental topics of Hartree-Fock theory in Quantum Chemistry. From the molecular Hamiltonian, using and discussing the Born-Oppenheimer approximation, we arrive to the Hartree and Hartree-Fock equations for the electronic problem. Special emphasis is placed in the most relevant mathematical aspects of the theoretical derivation of the final equations, as well as in the results regarding the existence and uniqueness of their solutions. All Hartree-Fock versions with different spin restrictions are systematically extracted from the general case, thus providing a unifying framework. Then, the discretization of the one-electron orbitals space is reviewed and the Roothaan-Hall formalism introduced. This leads to a exposition of the basic underlying concepts related to the construction and selection of Gaussian basis sets, focusing in algorithmic efficiency issues. Finally, we close the review with a section in which the most relevant modern developments (specially those related to the design of linear-scaling methods) are commented and linked to the issues discussed. The whole work is intentionally introductory and rather self-contained, so that it may be useful for non experts that aim to use quantum chemical methods in interdisciplinary applications. Moreover, much material that is found scattered in the literature has been put together here to facilitate comprehension and to serve as a handy reference.Comment: 64 pages, 3 figures, tMPH2e.cls style file, doublesp, mathbbol and subeqn package

Surgical management of low grade isthmic spondylolisthesis; a randomized controlled study of the surgical fixation with and without reduction

<p>Abstract</p> <p>Background</p> <p>spondylolisthesis is a condition in which a vertebra slips out of the proper position onto the bone below it as a result of pars interarticularis defect. The slipped segment produces abnormal positioning of the vertebrae in relation to each other along the spinal column and causes mechanical back pain and neural breach.</p> <p>Materials and methods</p> <p>A randomized and double blinded study consisted of 41 patients aged 36-69 years (18 females and 28 males) treated for symptomatic spondylolisthesis between December,2006 and December, 2009. All patients were randomly distributed into two groups I and II. Twenty patients were in Group I; they underwent reduction of the slipped vertebrae by using Reduction-Screw Technique and posterior lumbar interbody fixation (PLIF). Group II consisted of twenty one patients who underwent only surgical fixation (PLIF) without reduction. All patients in this study had same pre and post operative management.</p> <p>Results</p> <p>only one case had broken rod in group I that required revision. Superficial wound infection was experienced in two patients and one patient, from group II, developed wound hematoma. The outcome in both groups was variable on the short term but was almost the same on the long term follow up.</p> <p>Conclusion</p> <p>surgical management of symptomatic low grade spondylolisthesis should include neural decompression and surgical fixation. Reduction of slipped vertebral bodies is unnecessary as the ultimate outcome will be likely similar.</p

Crystal Structure of a Charge Engineered Human Lysozyme Having Enhanced Bactericidal Activity

Human lysozyme is a key component of the innate immune system, and recombinant forms of the enzyme represent promising leads in the search for therapeutic agents able to treat drug-resistant infections. The wild type protein, however, fails to participate effectively in clearance of certain infections due to inherent functional limitations. For example, wild type lysozymes are subject to electrostatic sequestration and inactivation by anionic biopolymers in the infected airway. A charge engineered variant of human lysozyme has recently been shown to possess improved antibacterial activity in the presence of disease associated inhibitory molecules. Here, the 2.04 Å crystal structure of this variant is presented along with an analysis that provides molecular level insights into the origins of the protein's enhanced performance. The charge engineered variant's two mutated amino acids exhibit stabilizing interactions with adjacent native residues, and from a global perspective, the mutations cause no gross structural perturbations or loss of stability. Importantly, the two substitutions dramatically expand the negative electrostatic potential that, in the wild type enzyme, is restricted to a small region near the catalytic residues. The net result is a reduction in the overall strength of the engineered enzyme's electrostatic potential field, and it appears that the specific nature of this remodeled field underlies the variant's reduced susceptibility to inhibition by anionic biopolymers

Fetal Programming of Adult Glucose Homeostasis in Mice

BACKGROUND: Emerging evidence suggests that dietary soy and phytoestrogens can have beneficial effects on lipid and glucose metabolism. We have previously shown that male mice fed from conception to adulthood with a high soy-containing diet had reduced body weight, adiposity and a decrease in glucose intolerance, an early marker of insulin resistance and diabetes. OBJECTIVES: The purpose of this study was to identify the precise periods of exposure during which phytoestrogens and dietary soy improve lipid and glucose metabolism. Since intrauterine position (IUP) has been shown to alter sensitivity to endocrine disruptors, we also investigated whether the combination of IUP and fetal exposure to dietary phytoestrogens could potentially affect adult metabolic parameters. METHODS: Male outbred mice (CD-1) were allowed ad libitum access to either a high soy-containing diet or a soy-free diet either during gestation, lactation or after weaning. Adiposity and bone mass density was assessed by dual x-ray absorptiometry. Glucose tolerance was assessed by a glucose tolerance test. Blood pressure was examined by the tail-cuff system. RESULTS: Here we show that metabolic improvements are dependent on precise windows of exposure during life. The beneficial effects of dietary soy and phytoestrogens on adiposity were apparent only in animals fed post-natally, while the improvements in glucose tolerance are restricted to animals with fetal exposure to soy. Interestingly, we observed that IUP influenced adult glucose tolerance, but not adiposity. Similar IUP trends were observed for other estrogen-related metabolic parameters such as blood pressure and bone mass density. CONCLUSION: Our results suggest that IUP and fetal exposure to estrogenic environmental disrupting compounds, such as dietary phytoestrogens, could alter metabolic and cardiovascular parameters in adult individuals independently of adipose gain

Hepatocellular carcinoma in Pakistan: where do we stand?

Context: From the 1970s till the mid 1990s, hepatitis B was the most common etiological factor for hepatocellular carcinoma (HCC) in Pakistan. Afterwards, a shift in HCC etiology was observed with a steady rise in hepatitis C virus (HCV) related HCC cases. HCV-3a, which is the most prevalent genotype, is also most frequent in HCV related HCC. There was an increase in the proportion of non-B non-C (NBNC) HCC cases as well, which might be attributed to an increase in non-alcoholic fatty liver disease. Evidence Acquisition: The age-standardized rate for HCC is 7.64/100 000 in males and 2.8/100 000 in females. Male to female ratio is 3.6:1. Usual age of presentation is in the fifth and sixth decade. Most patients present with advanced disease, as they are not in a regular surveillance program. This is more so for patients with NBNC chronic liver disease. As many sonologists in Pakistan are practicing without sufficient training to pick up early lesions, alpha-fetoprotein is still recommended to compliment ultrasound in the surveillance of HCC. Results: Majority of HCC patients present with nonresectable disease. Interventions such as transarterial chemoembolization, radiofrequency ablation, resection and chemotherapy including sorafenib are available in selected centers. Pakistan appears to be in an area of intermediate endemicity for HCC. There is a need for population based epidemiological studies to estimate the exact disease burden. Conclusions: Measures to prevent the spread of hepatitis C and B can slow down the epidemic rise in the incidence of HCC in the coming decades. There is a need to implement a proper surveillance program to identify HCC cases at an early stage

Do people with risky behaviours participate in biomedical cohort studies?

BACKGROUND: Analysis was undertaken on data from randomly selected participants of a bio-medical cohort study to assess representativeness. The research hypotheses was that there was no difference in participation and non-participations in terms of health-related indicators (smoking, alcohol use, body mass index, physical activity, blood pressure and cholesterol readings and overall health status) and selected socio-demographics (age, sex, area of residence, education level, marital status and work status). METHODS: Randomly selected adults were recruited into a bio-medical representative cohort study based in the north western suburbs of the capital of South Australia – Adealide. Comparison data was obtained from cross-sectional surveys of randomly selected adults in the same age range and in the same region. The cohort participants were 4060 randomly selected adults (18+ years). RESULTS: There were no major differences between study participants and the comparison population in terms of current smoking status, body mass index, physical activity, overall health status and proportions with current high blood pressure and cholesterol readings. Significantly more people who reported a medium to very high alcohol risk participated in the study. There were some demographic differences with study participants more likely to be in the middle level of household income and education level. CONCLUSION: People with risky behaviours participated in this health study in the same proportions as people without these risk factors