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The dopamine transporter gene (DAT1) and visual memory deficits have been consistently reported to be associated with attention-deficit/hyperactivity disorder (ADHD). This study aimed to examine whether a DAT1 haplotype affected functional and structural brain alterations in children with ADHD and whether those alterations were associated with visual memory.
We recruited a total of 37 drug-naïve children with ADHD (17 with the DAT1 rs27048 (C)/rs429699 (T) haplotype and 20 without the CT haplotype) and 37 typically developing children (17 with the CT haplotype and 20 without the CT haplotype). Visual memory was assessed by the pattern recognition memory (PRM) and spatial recognition memory (SRM) tasks. We analyzed functional and structural brain architecture with regional homogeneity (ReHo) and gray matter volume (GMV).
The CT haplotype was associated with decreased ReHo in the left superior occipital gyrus, cuneus, and precuneus; and decreased GMV in the left superior occipital gyrus, cuneus, and precuneus, and in the right angular gyrus. Significant interactions of ADHD and the CT haplotype were found in the right postcentral gyrus for ReHo and in the right supplementary motor area for GMV. For the ADHD-CT group, we found negative correlations of total correct responses in PRM and SRM and positive correlations of mean latency of correct responses in PRM with the GMV in the left superior occipital gyrus, cuneus, and precuneus.
Our findings suggest that the DAT1-related GMV alterations in the posterior cortical regions may contribute to visual memory performance in children with ADHD.
Herbicide-resistant Echinochloa spp. pose a significant threat to U.S. rice production. Two surveys were conducted to characterize Echinochloa resistance to common rice herbicides and provide important demographic information on the populations in Arkansas: one was the Echinochloa Herbicide Resistance Confirmation Survey conducted annually since 2006; the other was the Echinochloa Herbicide Resistance Demographics Survey conducted since 2010. The Resistance Confirmation Survey showed that resistance to propanil (50%) was most prevalent, followed by quinclorac (23%), imazethapyr (13%), and cyhalofop (3%). Multiple resistance increased with time, with 27% of accessions being multiple-resistant, mostly to propanil+quinclorac (12%). The parallel Resistance Demographics Survey tested resistance by species. Of the 264 accessions collected, 73% were junglerice, 14% were rough barnyardgrass, and 11% were barnyardgrass. Overall, this survey also showed resistance to propanil (53%) and quinclorac (28%) being most prevalent, with low frequencies of resistance to cyhalofop (12%) and imazethapyr (6%). Resistance to herbicides was less frequent with barnyardgrass (54%) and rough barnyardgrass (28%) than with junglerice (73%). Multiple resistance was most frequent with junglerice (33%) and least frequent with rough barnyardgrass (8%). Across both surveys, the resistance cases were clustered in the northeast and Grand Prairie regions of the state. Herbicide resistance among Echinochloa populations in rice fields is continuing to increase in frequency and complexity. This is a consequence of sequential selection with different major herbicide sites of action, starting with propanil followed by quinclorac and others.
Multiwall carbon nanotubes (MWCNTs) are utilized to resolve low coupling coefficient issue by dispersing MWCNTs in poly(vinylidene fluoride) matrix to create stress reinforcing network, dispersant, and electron conducting functions for barium titanate (BT) nanoparticles. Various BT and MWCNT percentages of nanocomposite film are fabricated by FDM three-dimensional (3D) printing which can simplify the fabrication process as well as lower cost and design flexibility. Increasing MWCNTs and BT particles gradually increase piezoelectric coefficient (d31) by 0.13 pC/N with 0.4 wt%-MWCNTs/18 wt%-BT. These results provide not only a technique to print piezoelectric nanocomposites but also unique materials combination for sensor application.
This paper develops a model of the optimal timing of interest rate changes. With fixed adjustment costs and ongoing uncertainty, changing the interest rate involves the exercise of an option. Optimal policy therefore has a “wait-and-see” component, which can be quantified using option pricing techniques. We show that increased uncertainty makes the central bank more reluctant to change its target interest rate, and argue that this helps explain recent observed deviations from the Taylor Rule. An optimal wait-and-see policy fits the target interest rates of the Fed and Bank of Canada better than the Taylor Rule.
Understanding the organic chemistry of molecular clouds, particularly the formation of biologically important molecules, is fundamental to the study of the processes which lead to the origin, evolution and distribution of life in the Galaxy. Determining the level of molecular complexity attainable in the clouds, and the nature of the complex organic material available to protostellar disks and the planetary systems that form from them, requires an understanding of the possible chemical pathways and is therefore a central question in astrochemistry. We have thus searched for prebiologically important molecules in the hot molecular cloud cores: Sgr B2(N-LMH), W51 e1/e2 and Orion-KL. Among the molecules searched: Pyrimidine is the unsubstituted ring analogue for three of the DNA and RNA bases. 2H-Azirine and Aziridine are azaheterocyclic compounds. And Glycine is the simplest amino acid. Detections of these interstellar organic molecular species will thus have important implications for Astrobiology. Our preliminary results indicate a tentative detection of interstellar glycine. If confirmed, this will be the first detection of an amino acid in interstellar space and will greatly strengthen the thesis that interstellar organic molecules could have played a pivotal role in the prebiotic chemistry of the early Earth.
Carbon based materials have long been investigated as anodes for lithium ion batteries. Among these materials, porous carbon holds several advantages such as high stability, high specific surface area, and excellent cycling capability. To further enhance the energy storage performance, ceramic nanomaterials have been combined with carbon based materials as hybrid anodes for enhanced specific capacity. The use of metal oxide ceramic nanomaterials could enhance the surface electrochemical reactivity thus leads to the increasing of capacity retention at higher number of cycles. In this research, we synthesized ceria (CeO2) nano-particles on porous carbon to form inorganic-organic hybrid composites as an anode material for Li-ion battery. The high redox potential of ceria is expected to increase the specific capacity and energy density of the system. The electrochemical performance was determined by a battery analyzer. It is observed that the specific capacity could be improved by 77% using hybrid composites anode. The material morphology, crystal structure, and thermal stability were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), and Thermogravimetric Analysis (TGA).
The increasing demand for energy storage devices has propelled research for developing efficient super-capacitors (SC) with long cycle life and ultrahigh energy density. Carbon-based materials are commonly used as electrode materials for SC. Herein, we report a new approach to improve the SC performance utilizing a Porous Carbon/Cerium Oxide nanoparticle (PC-CON) hybrid as electrode material synthesized via a low temperature hydrothermal method. Through this approach, charges can be stored not only via electrochemical double layer capacitance (EDLC) from PC but also through pseudo-capacitive effect from CeO2 nanoparticles (NPs). The electrode-electrolyte interaction due to the electrochemical properties of the electrolyte provides an enhanced voltage window for the SC. Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and X-Ray Diffraction (XRD) measurements were used for the characterization of this PC/CeO2 hybrid material system. The testing results have shown that a maximum of 500% higher specific capacitance could be obtained using PC/CeO2 instead of using PC only.
There are two marine species in the genus Ozobranchus. Ozobranchus branchiatus mainly parasitizes green turtles and O. margoi parasitizes most turtle species. We used sequences for the mitochondrial cytochrome c oxidase subunit I gene (COI sequence analysis), along with morphological diagnosis, to compare the population genetic structures of O. branchiatus and O. margoi collected near Taiwan to those of their populations in the Atlantic. The results provide estimates of the genetic divergence between these leeches in the two regions. Ozobranchus branchiatus had a greater pairwise distance within Taiwan (0.0031–0.0141) than O. margoi (no differences). Phylogenetic tree analysis identified one O. branchiatus clade and one O. margoi clade in Taiwan. The better environmental adaptability and lower host specificity of O. margoi might result in lower genetic divergence among populations.
Autism spectrum disorder (ASD) is a highly heritable neurodevelopmental disorder, yet the search for definite genetic etiologies remains elusive. Delineating ASD endophenotypes can boost the statistical power to identify the genetic etiologies and pathophysiology of ASD. We aimed to test for endophenotypes of neuroanatomy and associated intrinsic functional connectivity (iFC) via contrasting male youth with ASD, their unaffected brothers and typically developing (TD) males.
The 94 participants (aged 9–19 years) – 20 male youth with ASD, 20 unaffected brothers and 54 TD males – received clinical assessments, and undertook structural and resting-state functional magnetic resonance imaging scans. Voxel-based morphometry was performed to obtain regional gray and white matter volumes. A seed-based approach, with seeds defined by the regions demonstrating atypical neuroanatomy shared by youth with ASD and unaffected brothers, was implemented to derive iFC. General linear models were used to compare brain structures and iFC among the three groups. Assessment of familiality was investigated by permutation tests for variance of the within-family pair difference.
We found that atypical gray matter volume in the mid-cingulate cortex was shared between male youth with ASD and their unaffected brothers as compared with TD males. Moreover, reduced iFC between the mid-cingulate cortex and the right inferior frontal gyrus, and increased iFC between the mid-cingulate cortex and bilateral middle occipital gyrus were the shared features of male ASD youth and unaffected brothers.
Atypical neuroanatomy and iFC surrounding the mid-cingulate cortex may be a potential endophenotypic marker for ASD in males.
We aimed to investigate the feasibility of delivering stereotactic radiosurgery (SRS) or hypofractionated stereotactic radiotherapy with the hybrid MRI-LINAC (MRL) system for patients with single brain metastases, and to characterize the dosimetric impact at tissue-air interfaces resulting from the electron return effect (ERE). Material/Methods: 24 patients treated for intact single brain metastases were selected for analysis. Three optimized radiotherapy plans with the same prescribed dose were generated for each case: 1) standard noncoplanar volumetric modulated arc therapy (VMAT), 2) coplanar step-and-shoot intensity modulated radiotherapy (IMRT) on the MRL in the absence (MRL_B=0), and 3) in the presence of the transverse magnetic field (MRL_B=1.5). The plans were evaluated using cumulative dose-volume histograms (DVHs) and by calculation of Paddick conformity index (PCI), V100%, V12Gy minus gross tumor volume (V12Gy – GTV), and V2Gy. The dosimetric impact of ERE to the skin and air cavities was quantified using a 5 mm rim of tissue around tissue-air boundaries. Results: All plans met the objectives with respective to target coverage and OAR constraints. Differences between all investigated dosimetric parameters significantly favored the VMAT plans as compared to the MRL_B=0 and MRL_B=1.5 plans, except for V2Gy. The VMAT plans showed a higher mean (±standard deviation) PCI compared to the MRL_B=0 and MRL_B=1.5 plans (0.85±0.08 vs. 0.79±0.09 vs. 0.78±0.11). In the presence of the magnetic field, ERE resulted in a statistically significant but small increase in mean dose and D2cc in the skin (0.08 Gy, p < 0.0001 and 0.66 Gy, p < 0.0001, respectively) and around air cavities (0.07 Gy, p = 0.0092 and 0.25 Gy, p = 0.0004, respectively). Conclusions: Stereotactic radiation to single brain metastases is feasible using the MRL Monaco treatment planning system; however, in its current iteration, application to small targets deserve careful consideration given the technical limitations resulting in less favorable plan quality compared to that of a noncoplanar standard VMAT technique. The dosimetric impact of ERE at tissue-air boundaries is minor and does not compromise target conformity or dose gradient.
Methylphenidate and atomoxetine are commonly prescribed for treating attention deficit hyperactivity disorder (ADHD). However, their therapeutic neural mechanisms remain unclear.
After baseline evaluation including cognitive testing of the Cambridge Neuropsychological Test Automated Battery (CANTAB), drug-naive children with ADHD (n = 46), aged 7–17 years, were randomly assigned to a 12-week treatment with methylphenidate (n = 22) or atomoxetine (n = 24). Intrinsic brain activity, including the fractional amplitude of low-frequency fluctuations (fALFF) and regional homogeneity (ReHo), was quantified via resting-state functional magnetic resonance imaging at baseline and week 12.
Reductions in inattentive symptoms were related to increased fALFF in the left superior temporal gyrus and left inferior parietal lobule for ADHD children treated with methylphenidate, and in the left lingual gyrus and left inferior occipital gyrus for ADHD children treated with atomoxetine. Hyperactivity/impulsivity symptom reductions were differentially related to increased fALFF in the methylphenidate group and to decreased fALFF in the atomoxetine group in bilateral precentral and postcentral gyri. Prediction analyses in the atomoxetine group revealed negative correlations between pre-treatment CANTAB simple reaction time and fALFF change in the left lingual gyrus and left inferior occipital gyrus, and positive correlations between pre-treatment CANTAB simple movement time and fALFF change in bilateral precentral and postcentral gyri and left precuneus, with a negative correlation between movement time and the fALFF change in the left lingual gyrus and the inferior occipital gyrus.
Our findings suggest differential neurophysiological mechanisms for the treatment effects of methylphenidate and atomoxetine in children with ADHD.
The collision between aqueous drops in air typically leads to coalescence after impact. Rebounding of the droplets with similar sizes at atmospheric conditions is not generated, unless with significantly large pressure or high impact parameters exhibiting near-grazing collision. Here we demonstrate experimentally the creation of a non-coalescent regime through addition of a small amount of water-soluble surfactant. We perform a direct simulation to account for the continuum and short-range flow dynamics of the approaching interfaces, as affected by the soluble surfactant. Based on the immersed-boundary formulation, a conservative scheme is developed for solving the coupled surface-bulk convection–diffusion concentration equations, which presents excellent mass preservation in the solvent as well as conservation of total surfactant mass. We show that the Marangoni effect, caused by non-uniform distributions of surfactant on the droplet surface and surface tension, induces stresses that oppose the draining of gas in the interstitial gap, and hence prohibits merging of the interfaces. In such gas–liquid systems, the repulsion caused by the addition of surfactant, as frequently observed in liquid–liquid systems such as emulsions in the form of an electric double-layer force, was found to be too weak to dominate in the attainable range of interfacial separation distances. These results thus identify the key mechanisms governing the impact dynamics of surfactant-coated droplets in air and imply the potential of using a small amount of surfactant to manipulate impact outcomes, for example, to prevent coalescence between droplets or interfaces in gases.
The relationship between white-matter tracts and executive functions (EF) in attention deficit hyperactivity disorder (ADHD) has not been well studied and previous studies mainly focused on frontostriatal (FS) tracts. The authors explored the microstructural property of several fibre tracts hypothesized to be involved in EF, to correlate their microstructural property with EF, and to explore whether such associations differ between ADHD and typically developing (TD) youths.
We assessed 45 youths with ADHD and 45 individually matched TD youths with a computerized test battery for multiple dimensions of EF. From magnetic resonance imaging, FS tract, superior longitudinal fasciculus (SLF), arcuate fasciculus (AF) and cingulum bundle (CB) were reconstructed by diffusion spectrum imaging tractography. The generalized fractional anisotropy (GFA) values of white-matter tracts were computed to present microstructural property of each tract.
We found lower GFA in the left FS tract, left SLF, left AF and right CB, and poorer performance in set-shifting, sustained attention, cognitive inhibition and visuospatial planning in ADHD than TD. The ADHD and TD groups demonstrated different association patterns between EF and fibre tract microstructural property. Most of the EF were associated with microstructural integrity of the FS tract and CB in TD youths, while with that of the FS tract, SLF and AF in youths with ADHD.
Our findings support that the SLF, AF and CB also involve in a wide range of EF and that the main fibre tracts involved in EF are different in youths with ADHD.
Vancomycin-resistant enterococci (VRE) infections are a public health threat associated with increased patient mortality and healthcare costs. Antibiotic usage, particularly cephalosporins, has been associated with VRE colonization and VRE bloodstream infections (VRE BSI). We examined the relationship between antimicrobial usage and incident VRE colonization at the individual patient level. Prospective, weekly surveillance was undertaken for incident VRE colonization defined by negative admission but positive surveillance swab in a medical intensive care unit over a 17-month period. Antimicrobial exposure was quantified as days of therapy (DOT)/1000 patient-days. Multiple logistic regression was used to analyse incident VRE colonization and antibiotic DOT, controlling for demographic and clinical covariates. Ninety-six percent (1398/1454) of admissions were swabbed within 24 h of intensive care unit (ICU) arrival and of the 380 patients in the ICU long enough for weekly surveillance, 83 (22%) developed incident VRE colonization. Incident colonization was associated in bivariate analysis with male gender, more previous hospital admissions, longer previous hospital stay, and use of cefepime/ceftazidime, fluconazole, azithromycin, and metronidazole (P < 0·05). After controlling for demographic and clinical covariates, metronidazole was the only antibiotic independently associated with incident VRE colonization (odds ratio 2·0, 95% confidence interval 1·2–3·3, P < 0·009). Our findings suggest that risk of incident VRE colonization differs between individual antibiotic agents and support the possibility that antimicrobial stewardship may impact VRE colonization and infection.
In this chapter, we present a MetaOmics software suite to combine multiple transcriptomic studies for meta-analysis. MetaOmics contains more than a dozen in-housedeveloped methods and consists of seven subpackages for different data analysis and biological objectives: MetaQC for quality control assessment, MetaDE for differentially expressed gene detection, MetaPath for pathway enrichment analysis, MetaPCA for dimension reduction, MetaClust for clustering analysis, MetaNetwork for network analysis, and MetaPredict for prediction analysis.With the increasing number of experimental data accumulated in the public domain, application of related omics metaanalysis methods provides increased statistical power and validated conclusions to improve disease treatment and mechanism understanding.
With the advances in high-throughput experimental technology in the past decades, the production of genomic data has become affordable and large genomic data are prevalent in recent biomedical research. Effective data management and analysis tools are essential to fully decipher the biological information inside the tremendous amount of experimental data. In the past decade, enormous bodies of transcriptomic data have been accumulated from microarray experiments, which resulted in several large public data depositories, such as Gene Expression Omnibus (GEO) and ArrayExpress. Recent development of next generation sequencing (NGS) technology accelerated the data accumulation in databases like Sequence Read Archive (SRA). In general, each individual study often has small or moderate sample size. As a result, the statistical power of candidate marker or pathway detection in each study is often limited, the reproducibility of the conclusions is relatively low, and the generalizability of the inferred information has been frequently criticized. Combining multiple studies has emerged as an appealing practice because of improved statistical power and estimation accuracy, while it may also provide validation about the final conclusion. Many “transcriptomic meta-analysis” methods have been developed and widely applied in the real data analysis. In the literature, however, most of the methods were proposed to identify candidate marker genes differentially expressed between two or multiple conditions. Similar “meta-analysis” ideas can be extended for enriched pathway detection, clustering analysis, dimension reduction, and network and disease classification analysis (see Ramasamy et al. (2008) and Tseng et al. (2012) for more details). In this chapter, we first introduce statistical methods in the “MetaOmics” software suite, including those still under development in our lab.
Limitations in sample size, overly inclusive antibiotic classes, lack of adjustment of key risk variables, and inadequate assessment of cases contribute to widely ranging estimates of risk factors for Clostridium difficile infection (CDI).
To incorporate all key CDI risk factors in addition to 27 antibiotic classes into a single comprehensive model.
Retrospective cohort study.
Kaiser Permanente Southern California.
Members of Kaiser Permanente Southern California at least 18 years old admitted to any of its 14 hospitals from January 1, 2011, through December 31, 2012.
Hospital-acquired CDI cases were identified by polymerase chain reaction assay. Exposure to major outpatient antibiotics (10 classes) and those administered during inpatient stays (27 classes) was assessed. Age, sex, self-identified race/ethnicity, Charlson Comorbidity Score, previous hospitalization, transfer from a skilled nursing facility, number of different antibiotic classes, statin use, and proton pump inhibitor use were also assessed. Poisson regression estimated adjusted risk of CDI.
A total of 401,234 patients with 2,638 cases of incident CDI (0.7%) were detected. The final model demonstrated highest CDI risk associated with increasing age, exposure to multiple antibiotic classes, and skilled nursing facility transfer. Factors conferring the most reduced CDI risk were inpatient exposure to tetracyclines and first-generation cephalosporins, and outpatient macrolides.
Although type and aggregate antibiotic exposure are important, the factors that increase the likelihood of environmental spore acquisition should not be underestimated. Operationally, our findings have implications for antibiotic stewardship efforts and can inform empirical and culture-driven treatment approaches.
Infect. Control Hosp. Epidemiol. 2015;36(12):1409–1416
The synthesis of biocompatible noble metal nanoparticles dispersible in a wide range of biological media with control of polycrystalinity and nanogeometry, pH sensitivity and salt tolerance has been a challenging requirements. The role of 3-aminopropyltrimethoxysilane (3-APTMS) and organic reducing reagents for real time synthesis of amphilic noble metal nanoparticles meeting these requirements are demonstrated justifying the following; (1) 3-APTMS capped noble metal ions are converted into respective metal nanoparticles in the presence of one of organic reducing agents i.e., cyclohexanone, tetrahydrofuran hydroperoxide (THF-HPO), formaldehyde, acetaldehyde, acetone, t-buty dimethyl keotone, 3-Glycidoxy-propyltrimethoxysilane (3-GPTMS); (2) 3-APTMS acts as micelle, promotes the interaction of metal ions with organic reducing agent, precisely controls the size of metal nanoparticles, pH sensititvity and salt tolerance and also provides a suitable medium for nanoparticles suspension, (3) the use of suitable organic reagent precisely controls the polarity of as made noble metal nanoparticles allowing specific biological interactions, and (4) 3-APTMS significantly increases the stability and controls the pH sensitivity and salt tolerance of metal nanoparticles. The as synthesized nanomaterials show potential viability in biomedical applications from many angles i.e. (a) as potential bioelectrocatalyst, (b) selective interaction with active proteins and cellular components, and (c) peroxidase mimetic.