The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Ethnic differences in relations between family process and child internalizing problems. Poster session presented at the biennial meeting of the Society for Research in Child Development,

Background: Family process variables have been linked to child problem behavior, but recent research suggests that child ethnicity may moderate relations between family process and child outcomes. The current study examined how ethnicity moderates relations between parent conflict, parent-child relationship quality, and internalizing problems. Methods: A sample of 101 mother-child dyads was drawn from a larger longitudinal study of childhood-onset depression. Maternal reports of family process factors were used with child reports of anxiety and depressive symptoms. Results: The results indicated a moderating effect of ethnicity for multiple indicators of internalizing symptoms, such that child-rearing disagreement and low levels of mother-child openness were associated with internalizing problems only for European American (not African American) children. Conclusions: Findings suggest that ethnicity moderates the effects of family process factors on child psychopathology. Ethnic differences may be accounted for by the normativeness of family processes and the meaning that children of different ethnic backgrounds assign to these processes

Maternal depression and child internalizing: The moderating role of child emotion regulation

This study tests a model of children’s emotion regulation (ER) as a moderator of the link between maternal depression and child internalizing problems. Participants were 78 children (ages 4 to 7), including 45 children of mothers with a history of child-hood-onset depression (COD) and 33 children of mothers who had never been de-pressed. ER was assessed observationally during a laboratory mood induction. ER behaviors were empirically reduced into 3 categories: (a) negative focus on delay, (b) positive reward anticipation, and (c) behavioral distraction. Linear mixed models in-dicated that positive reward anticipation moderated the effects of maternal COD on children’s internalizing problems, particularly if mothers had current depressive symptoms. Findings suggest that generating positive affect in the face of a potential frustration may be a protective ER strategy for children at risk for depression. Offspring of depressed parents are known to be at increased risk for depression and other psychiatric and psychosocial problems compared to the general population (Beardslee, Bemporad, Keller, & Klerman, 1983). Children of depressed parents are at a three- to fourfold risk for developing depression prior to adult

Wet chemical synthesis strategies to develop aluminum manganese nanoparticles for high density magnetic recording

As the technology era grows rapidly, there is always a need for quick access to stored data. Magnetic tape is one type of recording media used of information storage. Its main use in computer applications is for archival storage and mass storage systems. Magnetic tape is a multi-component material consisting of a base film with a top layer of magnetic particles. Particles that are used for magnetic recording devices must exhibit good magnetic properties including large coercivity and saturation magnetization. As the need for tape performance and storage capacity increases, new types of particulate media are needed to meet these demands. One candidate of particles for future magnetic tape is ferromagnetic AlMn nanoparticles. AlMn has a ferromagnetic tetragonal L10 phase which is exhibited by a class of transition metal alloy systems such as FePt, CoPt, FePd, MnPt, etc. This phase in the AlMn binary system is labeled as the τ phase and has a large anisotropy value of approximately 107 ergs/cc which translates to good magnetic properties suitable for use in magnetic tape. The advantages of producing AlMn nanoparticles for magnetic recording are the low cost and abundance of precursor materials. This dissertation investigated strategies of a solution phase chemical synthesis to produce AlMn nanoparticles. Metal nanoparticle systems are synthesized primarily by the reduction of metal salt precursors with a reducing agent in the presence of stabilizing agents in an organic solvent. Systems of metal nanoparticles with the tetragonal L10 phase characterized by high anisotropy values such as FePt and MnPt are produced via this route, and these techniques are considered as a foundation to make AlMn nanoparticles. Cyclic voltammetry experiments give the reduction potentials of Al and Mn precursors to determine suitable reducing agents. The results of the AlMn nanoparticle synthesis attempts are chronicled by the reducing agent that was used in the reaction. Different combinations of precursors, surfactants, and solvents are used in coordination with the following reducing agents: superhydride (C6H16BLi), potassium (K), hydrogen (H2), lithium aluminum hydride (LiAlH4), and sodium (Na). Also, synthesis attempts of AlMn(X) tertiary nanoparticles and core-shell AlMn nanoparticles are presented. (Published By University of Alabama Libraries

Cigarette Management System: An operating procedures guide to obtaining and managing investigational tobacco products for regulatory science research

Investigational tobacco products, specifically variable nicotine content research cigarettes (SPECTRUM), are available through the National Institute of Drug Abuse Drug Supply Program. Randomized controlled trials using research cigarettes are intended to support tobacco regulatory science research. The current paper provides an in-depth look into managing research cigarettes for two multi-site clinical trials and the design of a computer-based Cigarette Management System (CMS). The paper provides guidance intended for any investigator using similar products on the operating procedures under Good Clinical Practice standards and describes features of the CMS. The CMS and procedures described have been field tested for the past three years and have dispensed over 160,000 cigarette packs to participants. The CMS can accommodate a range of practical issues with real-world study implementation making it a robust application that is scalable to any study

Chemical vapor deposition of thin film materials for electronic and magnetic applications

Chemical vapor deposition (CVD) has been employed to pursue high quality thin film growth for four different materials with excellent electronic or magnetic properties for certain device applications. The relationship between CVD processing conditions and various thin film properties has been systematically studied. Plasma enhanced atomic layer deposition (PEALD) is a special type of CVD technique and can be used for the deposition of very thin (few nanometers) and highly conformal thin films. PEALD of hafnium nitride (HfN) thin film is studied by using tetrakis (dimethylamido) hafnium (IV) (TDMAH) and hydrogen plasma. Prior to thin film deposition, TDMAH adsorption and reaction on hydrogenated Si(100) surface has been investigated by in-situ ATR-FTIR. It has been found that between 100˚C and 150˚C surface adsorbed TDMAH molecules start to decompose based on the ß-hydride elimination mechanism. The decomposition species on the surface has been found hard to desorb at 150˚C, which can contaminate the thin film if the purging/pumping time is insufficient. Uniform and moderately conductive HfNxCy films are deposited on hydrogen terminated Si(100) and thermally grown SiO2 (on Si) substrates by PEALD process. The dependence of thin film resistivity on plasma power is found to be related to the change of surface chemical composition. In vacuo XPS depth profile analysis showed the existence of hafnium carbide phase, which to a certain degree can improve the film conductivity. Direct liquid injection chemical vapor deposition (DLI-CVD) has been utilized for epitaxial growth of nickel ferrite (NiFe2O4), lithium ferrite (LiFe5O8) and barium titanate (BaTiO3) films on various lattice match substrates. For the deposition of nickel ferrite, anhydrous Ni(acac)2 and Fe(acac)3 (acac = acetylacetonate) are used as precursor sources dissolved in N,N-dimethyl formamide (DMF) for the DLI vaporizer system. Epitaxial nickel ferrite films of stoichiometric composition are obtained in the temperature range of 500-800 ºC on both MgO(100) and MgAl2O4(100). Film morphology is found to be dependent on the deposition temperature with atomically smooth films being obtained for deposition temperature of 600 and 700 ºC. Magnetic measurements reveal an increase in the saturation magnetization for the films with increasing growth temperature, which correlates well with the trend for improved epitaxial growth. Nickel ferrite films deposited on MgAl2O4 (100) at 800ºC exhibit saturation magnetization very close to the bulk value of 300 emu/cm3. Out-of-plane FMR measurement shows the narrowest FMR line width of ~160 Oe for films deposited at 600˚C. For lithium ferrite deposition, anhydrous Li(acac) and Fe(acac)3 are dissolved in DMF in a molar ratio of 1:5. Epitaxial growth of lithium ferrite films on MgO(100) are observed in the temperature range of 500˚C to 800˚C. The as grown films show increasing saturation magnetization with increasing deposition temperature due to the improved degree of crystal texture. For barium titanate thin film deposition, Ba(hfa)2*tetraglyme and Ti(thd)2(OPri)2 are dissolved in toluene in a molar ratio of 1:1. Epitaxial growth of barium titanate on MgO(100) has been found at the temperature of 750˚C. Film with a thickness of ~500 nm has a relatively large roughness of ~20 nm. Small amount of F elements, which exists in Ba-F bonds, has been detected in the thin film by XPS. (Published By University of Alabama Libraries

Matilda: a mass filtered nanocluster source

Cluster science provides a good model system for the study of the size dependence of electronic properties, chemical reactivity, as well as magnetic properties of materials. One of the main interests in cluster science is the nanoscale understanding of chemical reactions and selectivity in catalysis. Therefore, a new cluster system was constructed to study catalysts for applications in renewable energy. Matilda, a nanocluster source, consists of a cluster source and a Retarding Field Analyzer (RFA). A moveable AJA A310 Series 1"-diameter magnetron sputtering gun enclosed in a water cooled aggregation tube served as the cluster source. A silver coin was used for the sputtering target. The sputtering pressure in the aggregation tube was controlled, ranging from 0.07 to 1torr, using a mass flow controller. The mean cluster size was found to be a function of relative partial pressure (He/Ar), sputtering power, and aggregation length. The kinetic energy distribution of ionized clusters was measured with the RFA. The maximum ion energy distribution was 2.9 eV/atom at a zero pressure ratio. At high Ar flow rates, the mean cluster size was 20 ~ 80nm, and at a 9.5 partial pressure ratio, the mean cluster size was reduced to 1.6nm. Our results showed that the He gas pressure can be optimized to reduce the cluster size variations. Results from SIMION, which is an electron optics simulation package, supported the basic function of an RFA, a three-element lens and the magnetic sector mass filter. These simulated results agreed with experimental data. For the size selection experiment, the channeltron electron multiplier collected ionized cluster signal at different positions during Ag deposition on a TEM grid for four and half hours. The cluster signal was high at the position for neutral clusters, which was not bent by a magnetic field, and the signal decreased rapidly far away from the neutral cluster region. For cluster separation according to mass to charge ratio in a magnetic sector mass filter, the ion energy of the cluster and its distribution must be precisely controlled by acceleration or deceleration. To verify the size separation, a high resolution microscope was required. Matilda provided narrow particle sized distribution from atomic scale to 4nm in size with different pressure ratio without additional mass filter. It is very economical way to produce relatively narrow particle size distribution. (Published By University of Alabama Libraries

Bromophycoic Acids: Bioactive natural products from a Fijian red alga Callophycus sp.

Bioassay-guided fractionation of extracts from a Fijian red alga in the genus Callophycus resulted in the isolation of five new compounds of the diterpene-benzoate class. Bromophycoic acids A"12E (1"125) were characterized by NMR and mass spectroscopic analyses and represent two novel carbon skeletons, one with an unusual proposed biosynthesis. These compounds display a range of activities against human tumor cell lines, malarial parasites, and bacterial pathogens including low micromolar suppression of MRSA and VREF