P200 and phonological processing in Chinese word recognition

The present study examined the relationship between P200 and phonological processing in Chinese word recognition. Participants did a semantic judgment task on pairs of words. The critical pairs were all semantically unrelated in one of three conditions: homophonic, rhyme, or phonologically unrelated. Noting the possibility that P200 may be affected by phonological similarity and orthographic similarity and that literature studies may not have assessed such effects separately, the present study used visually dissimilar word pairs sharing no phonetic radicals. Relative to the control pairs, both the homophonic and rhyme pairs elicited a significantly larger P200 with a scalp distribution centering at the centro-parietal areas. The results present strong evidence that P200 can be modulated by lexical phonology alone, independent of sub-lexical phonology, or lexical or sub-lexical orthography. P200 effects were comparable in amplitude and topography between the homophonic and the rhyme conditions, suggesting that P200 is sensitive to phonology at both the syllabic and the sub-syllabic levels.

A strain-driven morphotropic phase boundary in BiFeO3

Piezoelectric materials, which convert mechanical to electrical energy and vice versa, are typically characterized by the intimate coexistence of two phases across a morphotropic phase boundary. Electrically switching one to the other yields large electromechanical coupling coefficients. Driven by global environmental concerns, there is currently a strong push to discover practical lead-free piezoelectrics for device engineering. Using a combination of epitaxial growth techniques in conjunction with theoretical approaches, we show the formation of a morphotropic phase boundary through epitaxial constraint in lead-free piezoelectric bismuth ferrite (BiFeO3) films. Electric field-dependent studies show that a tetragonal-like phase can be reversibly converted into a rhombohedral-like phase, accompanied by measurable displacements of the surface, making this new lead-free system of interest for probe-based data storage and actuator applications.

Evaluation of Seed and Soil Treatments with Novel Bacillus subtilis Strains for Control of Soybean Root Rot Caused by Fusarium oxysporum and F. graminearum

Fusarium root rot is an important disease of soybean in Ontario, Canada. This study is to select antagonistic bacterial agents as effective alternatives to chemical pesticides for the control of root rots caused by Fusarium oxysporum and F. graminearum. Twenty-two Bacillus subtilis strains from soybean and corn roots were tested in dual cultures for inhibition of mycelial growth of F. oxysporum and F. graminearum. All strains significantly reduced mycelial growth of F. oxysporum by approximately 17 to 48% and of F. graminearum by 10 to 32%. Ten B. subtilis strains selected based on their larger fungal inhibition zones were evaluated against macroconidial germination. These strains inhibited the spore germination of F. oxysporum by 20 to 48% and of F. graminearum by 14 to 32% in cell-free filtrates. Under greenhouse conditions, the efficacy of seed and soil treatments with B. subtilis strains against the two Fusarium root rot pathogens was evaluated based on root rot severity, seedling emergence, plant height, and root dry weight. Six B. subtilis strains (SB01, SB04, SB23, SB24, SB28, and SB33) from soybean roots and two strains (CB01 and CH22) from corn roots significantly reduced the severity of the two Fusarium root rots in seed or soil treatments. Strains SB01, SB04, SB23, and SB24 were the most effective treatments against both pathogens in either seed or soil treatment. When applied as seed treatments, these four strains reduced root rot severity by 43 to 63% and increased emergence by 13 to 17%, plant height by 9 to 18%, and root dry weight by 8.4 to 19%. When used as soil treatments, they reduced root rot severity by 68 to 74% and increased emergence by 14 to 18%, plant height by 11 to 23%, and root dry weight by 16 to 24%. These results suggest that the novel strains of B. subtilis identified in this research can be effective alternatives to fungicides in managing Fusarium root rots of soybean, and a greater level of efficacy may be achieved when they were used as soil treatments than seed treatments.

The morphology of Au@MgO nanopeapods

The structure of metal nanoparticles embedded inside dielectric nanowires/nanotubes, namely nanopeapods, has been of increasing interest due to their unusual photoresponse and optical adsorption properties. This paper presents a type of new inorganic nanopeapod: faceted Au nanoparticles inside MgO nanowires. The Au self-assembles into a nanoparticle chain during the vapor-liquid-solid growth of the MgO nanowires for which gold also serves as the catalyst. Surprisingly such a chain can follow the whole axis of the MgO nanowires even if the latter zigzag, provided that the amount of gold is sufficient. It is shown that such Au@MgO nanopeapods form not only under metalorganic chemical vapor deposition conditions (Lai et al 2009 Appl. Phys. Lett. 94 022904), but also under our conventional vapor transport deposition condition. This new nanopeapod material might be a candidate for the study of electronic and/or plasmonic wave transport along nanowires.

Risk and protective factors in association with mental health problems among people living with HIV who were former plasma/blood donors in rural China

A random sample of 271 people living with HIV (PLWH) who were former plasma/blood donors and a convenience sample of 67 HIV negative villagers were anonymously interviewed. Compared with the non-PLWH, PLWH reported higher prevalence of symptoms of depression (adjusted OR = 2.53, p=0.001), anxiety (adjusted OR = 1.85, p=0.04), and stress (adjusted OR = 1.77, p=0.06). Of the PLWH respondents, 81.7% received Highly Active Antiretroviral Therapy (HAART); 32.1% of whom reported some side effects. Respectively 13.7%, 37.4%, and 38.4% PLWH perceived discrimination from their family members, relatives/friends, and neighbors. Absence of HAART, poor physical function, perceived discrimination from relatives and friends, and low level of resilience were associated with depression (stepwise regression; beta = - 0.28-0.17, R-square = 0.22), anxiety and stress (R-square = 0.32 and 0.16, respectively). The majority of respondents (70.1%) desired group intervention as a means for providing psychological support services. Relevant programs should both remove risk factors (e.g., absence of medical treatment, HIV-related discrimination) and promote protective factors (e.g., resilience). Support group is one of the potentially useful approaches to provide psychological support services.

Alterations in the processing of non-drug-related affective stimuli in abstinent heroin addicts

Long-term exposure to drug may alter the neural system associated with affective processing, as evidenced by both clinical observations and behavioral data documenting dysfunctions in emotional experiences and processing in drug addicts. Although many imaging studies examined neural responses to drug or drug-related cues in addicts, there have been few studies explicitly designed to reveal their neural abnormalities in processing non-drug-related natural affective materials. The present study asked abstinent heroin addicts and normal controls to passively view standardized affective pictures of positive, negative, or neutral valence and compared their brain activities with functional MRI. Compared to normal controls, addicts showed reduced activation in right amygdala in response to the affective pictures, consistent with previous reports of blunted subjective experience for affective stimuli in addicts. Furthermore, in two visual cortical areas BA 19 and 37, while the controls showed greater responses to positive pictures than to negative ones replicating literature findings, the addicts showed the opposite pattern. The results reveal a complex pattern of altered processing of non-drug-related affective materials in addicts showing both heightened and blunted neural responses in different brain regions and for different stimulus valence. The present study highlights the importance of brain imaging research on drug addicts' processing of affective stimuli in understanding disruptions in their emotion circuitry.

Contextual effects on number-time interaction

Time perception has long been known to be affected by numerical representations. Recent studies further demonstrate that when participants estimate the duration of Arabic numbers, number magnitude, though task-irrelevant, biases duration judgment to produce underestimation for smaller numbers and overestimation for larger numbers. Such effects were found in the present study to be significantly reduced when a weight unit gram was suffixed to the numbers rendering the mental magnitude differences between different numbers less distinctive. The effects were enhanced when a different unit kilogram was suffixed to the numbers enlarging the perceived magnitude differences between different numbers. The results indicate that effects of number magnitude on duration estimation should not be attributed to the mathematical differences between numbers but to how the numbers are perceived to differ from each other in magnitude in specific contexts when they denote concrete items. The results also provide new evidence for the theoretical proposal of a common generalized magnitude system and indicate that the system must be extended to include other action-oriented magnitudes, such as weight.

Enhanced Field Emission from Argon Plasma-Treated Ultra-sharp alpha-Fe(2)O(3) Nanoflakes

Hematite nanoflakes have been synthesized by a simple heat oxide method and further treated by Argon plasmas. The effects of Argon plasma on the morphology and crystal structures of nanoflakes were investigated. Significant enhancement of field-induced electron emission from the plasma-treated nanoflakes was observed. The transmission electron microscopy investigation shows that the plasma treatment effectively removes amorphous coating and creates plenty of sub-tips at the surface of the nanoflakes, which are believed to contribute the enhancement of emission. This work suggests that plasma treatment technique could be a direct means to improve field-emission properties of nanostructures.

Fertility preservation for female cancer patients: early clinical experience

OBJECTIVE

To characterize the early experience of a clinical program designed to provide strategies for fertility preservation to female cancer patients about to undergo chemotherapy or radiation therapy.

DESIGN

Retrospective chart review; case-control study.

SETTING

Academic medical center.

PATIENT(S)

Sixty-five female cancer patients and 57 age-matched infertility patients.

INTERVENTION

Enrollment in a program for fertility preservation.

MAIN OUTCOME MEASURE(S)

Choice of active participation, fertility preservation option selection, clinical outcomes of patients undergoing oocyte retrieval, attitudes regarding embryo disposition.

RESULT(S)

Of 65 patients referred to the program, 18 declined to undergo embryo, oocyte, or tissue cryopreservation. Six were found not to be eligible for medical reasons. Of the remaining 41 patients, 35 chose to cryopreserve embryos, four chose to cryopreserve oocytes, and two chose to undergo ovarian tissue freezing. Fewer oocytes were recovered from the embryo cryopreservation group when compared with an age-matched control group, but the mean number of zygotes generated was similar. Attitudes regarding embryo disposition were different between the two groups. No serious clinical sequelae resulted from participation.

CONCLUSION(S)

Fertility preservation techniques employing available technology may provide safe and practical options to female cancer patients facing chemotherapy or radiation therapy. A significant number of otherwise appropriate participants decline active management. Cancer patients display different attitudes regarding embryo disposition when compared with infertility patients without cancer.

An ERP study on the time course of phonological and semantic activation in Chinese word recognition

With the event-related potential (ERP) technique, we examined the time course of phonological and semantic activation in Chinese word recognition. Participants did a semantic judgment task and a homophone judgment task over the same set of word pairs. Each pair was of either high or low word frequency and the two words were either unrelated or related semantically or phonologically, i.e., being homophones. For high-frequency words, both the semantically related pairs in the homophone task and the homophonic pairs in the semantic task elicited ERP responses different from the unrelated control pairs in the N400 component but not any component earlier, suggesting a similar time course for semantic and phonological activation. For low-frequency words, the semantically related pairs in the homophone task were associated with a similar modulation of N400. However, compared to the unrelated controls, the homophonic pairs in the semantic task elicited a larger P200, a component implicated in phonological processing in the literature, and thus demonstrated a phonological activation earlier than semantic activation. The results showed that word frequency affects the time course of semantic and phonological activation suggesting that phonology is not invariably activated before semantics in Chinese word recognition.

Neural correlates of regulation of positive and negative emotions: an fmri study

Regulation of emotion is important for adaptive social functioning and mental well-being. This functional magnetic resonance imaging study identified neural correlates of regulation of positive or negative emotion. Twelve healthy female Chinese participants performed the experimental task that required them to simply view emotional pictures or to regulate their emotions induced by these pictures while their brain activities were monitored by a 1.5 T MRI scanner. The neuroimaging findings indicate that the left superior and lateral frontal regions (BA8/9) are common neural correlates of regulation of both emotions. For regulation of positive or negative emotion, changes of BOLD responses in the prefrontal regions and the left insula are associated with regulation of positive emotion; whereas activity of the left orbitofrontal gyrus, the left superior frontal gyrus, and the anterior cingulate gyrus appears to be involved in regulation of negative emotion. According to the participants' self-report, they appeared to be more effective in regulating positive than negative emotions, which may relate to the distinct patterns of neural activity associated with regulation of the specific emotion. As a conclusion, our findings suggest that there are shared as well as valence-specific neurocognitive mechanisms underlying regulation of positive and negative emotions. Enhanced knowledge about the neural mechanisms of emotion regulation helps improve understanding of the complex interplay of emotion and cognition underlying human behaviors.

Multifunctional CuO nanowire devices: p-type field effect transistors and CO gas sensors

We report the properties of a field effect transistor (FET) and a gas sensor based on CuO nanowires. CuO nanowire FETs exhibit p-type behavior. Large-scale p-type CuO nanowire thin-film transistors (10(4) devices in a 25 mm(2) area) are fabricated and we effectively demonstrate their enhanced performance. Furthermore, CuO nanowire exhibits high and fast response to CO gas at 200 degrees C, which makes it a promising candidate for a poisonous gas sensing nanodevice.

Optimizing double emulsion process to decrease the burst release of protein from biodegradable polymer microspheres

The process parameters such as the compositions of inner and outer aqueous phase and emulsification technique of the primary emulsion were optimized to decrease the burst release of BSA from biodegradable polymer microspheres in double emulsion method. It was found that diminished burst release of -14% was achieved for the microspheres produced by formulations, where no phosphate was present in the inner water phase (non-buffered system). Primary emulsion made by probe sonication rather than homogenization or mechanical stirring led to microspheres with insignificant burst effect. Microspheres obtained using 0.1% aqueous Tween 80 solution as the outer aqueous phase, frequently exhibit reduced burst effect of 2.7%. Low microsphere yield (52.1%), however, was observed. Microsphere yield was, therefore, enhanced by addition of additive such as sodium chloride, glucose or mannitol into the outer aqueous phase. Decrease in BSA entrapment was observed in the presence of sodium chloride, but reduction in entrapment efficiency was observed in the case of glucose. Burst release increased from 2.7% to 9.5% or 3.4% as 2.5% sodium chloride or 7.5% glucose was added into the outer aqueous phase respectively. Marked burst release (>20%) was observed in the presence of additive of higher concentration independent of sodium chloride or glucose. As far as surfactant type was concerned, diminished burst was found when PVP or Tween 80 rather than PVA was utilized as the surfactant during microsphere preparation. In addition to PLGA, the copolymers of L-lactide (LLA) and dimethyl trimethylene carbonate (DTC) or trimethylene carbonate (TMC) were also evaluated. Insignificant burst effect was found for the microspheres composed of DTC or TMC copolymers.

Preparation of bovine serum albumin loaded poly (D, L-lactic-co-glycolic acid) microspheres by a modified phase separation technique

BSA-loaded mcirospheres were prepared by a modified phase separation method, in which petroleum ether (PE) containing a certain amount of Span 80 rather than poly (dimethylsiloxane) (PDMS) was adopted as coacervating agent. Process parameters such as Span 80 concentration, the volume and addition rate of coacervating agent, polymer concentration, agitation rate during the phase separation process and PE type were evaluated to optimize the protein encapsulation. It was found microspheres with high yield (>80.0%) and entrapment efficiency (>90%) could be obtained using PE containing 5.0% Span 80 as the coacervating agent. Microspheres with small particle size (<10 microm) could be produced successfully with appropriate process parameters. In vitro release study suggested that burst release was significantly influenced by Span 80 concentration, polymer concentration and PE type and the burst release could be reduced to <20% with optimized formulation. A biphasic release behavior in vitro test was observed for the microspheres prepared by this method. GC analysis demonstrated that residual solvent of DCM and petroleum ether was decreased dramatically in comparison with PDMS used as a conventional coacervating agent.

An improvement of double emulsion technique for preparing bovine serum albumin-loaded PLGA microspheres

A modified double emulsion technique was adopted to prepare bovine serum albumin (BSA) loaded poly (D,L-lactic-co-glycolic acid) (PLGA) microspheres. In the formulations, polysorbates (Tween) such as Tween20, Tween40 or Tween80, instead of frequently used poly (vinyl alcohol) (PVA), was used as the emulsifier. Microspheres with porous surface, large particle size, low microsphere yield (approximately 65.4%) and BSA entrapment efficiency (approximately 25.2%) were obtained when Tween80 aqueous solution alone was used as the outer aqueous phase. However, microspheres with smooth surface, high yield and BSA entrapment efficiency could be produced successfully by introducing sodium chloride or glucose into the outer aqueous phase. Adding 5.0%(w/v) sodium chloride into the continuous phase led to increase in microsphere yield and BSA entrapment efficiency from 65.4% and 25.2% to approximately 100% and 76.6%, respectively. Microsphere yield and BSA entrapment efficiency increased from 64.5% and 25.2% to 97.2% and 89.3%, respectively, when 15.0%,(w/v) glucose was added into the continuous phase. In constrast to the microspheres prepared in the presence of additive, a more marked burst release was observed for microspheres prepared without additive in the continuous phase, which may be attributed to the porous morphology of the latter.

Verbal working memory deficits in abstinent heroin abusers

BACKGROUND

A prevailing belief is that opioids tend not to impair cognitive performance in opioid-dependent users. However, the impact of heroin abuse on verbal memory, especially on working memory, is not well studied and the results available are inconsistent.

OBJECTIVE

This study was carried out to test the hypothesis that abstinent heroin abusers have intact working memory capacity.

METHODS

N-back task and backward digit span task were used to measure the verbal working memory capacity in 28 abstinent heroin abusers and 25 controls matched for age, education level and gender. Forward digit span task was used as a control task to measure short-term memory capacity.

RESULTS

Compared with the control subjects, heroin abusers showed normal backward/forward digit spans but significant performance impairment in the n-back task.

CONCLUSION

Abstinent heroin abusers have intact short-term memory capacity but impaired verbal working memory capacity.

Mammary gland expression of antibacterial peptide genes to inhibit bacterial pathogens causing mastitis

As a step toward prevention of bovine mastitis, a plasmid-mediated gene transfer technique was used to enable mammary cells to synthesize and secrete bovine lactoferricin and bovine tracheal antibacterial peptides. For this purpose, a series of mammary tissue-specific expression vectors, harboring the antibacterial peptide gene, the 5'-flanking regulation sequence of goat beta-casein, and the bovine growth hormone polyadenylation signal sequence, were constructed using a eukaryotic expression vector pIRES1-neo. The mammary gland tissue-specific expression vector carrying the antimicrobial peptide genes dissolved in physiologic saline was injected directly into the lactating mammary glands of goats. The milk samples after injection were checked by Tricine-SDS-PAGE and bacterium inhibition zone assay. The results of these tests showed that the mammary gland tissue-specific expression vector driven by the goat beta-casein gene promoter could efficiently direct the expression of antibacterial peptides in goat milk; the expression of antibacterial proteins lasted for 3 to 6 d. All of the milk samples collected from the mammary glands that had been injected with different vectors harboring the antibacterial peptide gene(s) exhibited bacteriostatic activity against different bacterial pathogens. These results demonstrated that the mammary gland tissue-specific expression vector could be used to introduce antibacterial peptide gene into the goat mammary gland, enabling secretion of a bioactive form of antibacterial peptide in the milk. This successful expression of antibacterial peptides in goat mammary glands provided a possible method to prevent mastitis in ruminants.

Strain-induced polarization rotation in epitaxial (001) BiFeO3 thin films

Direct measurement of the remanent polarization of high quality (001)-oriented epitaxial BiFeO3 thin films shows a strong strain dependence, even larger than conventional (001)-oriented PbTiO3 films. Thermodynamic analysis reveals that a strain-induced polarization rotation mechanism is responsible for the large change in the out-of-plane polarization of (001) BiFeO3 with biaxial strain while the spontaneous polarization itself remains almost constant.

An electrophysiological signature for proactive interference resolution in working memory

We used event-related potentials (ERPs) to study the temporal dynamics of proactive interference in working memory. Participants performed a Sternberg item-recognition task to determine whether a probe was in a target memory set. Familiar negative probes were found to be more difficult to reject than less familiar ones. A fronto-central N2 component peaking around 300 ms post-probe-onset differentiated among target probes, familiar and less familiar non-target probes. The study identifies N2 as the ERP signature for proactive interference resolution. It also indicates that the resolution process occurs in the same time window as target/non-target discrimination and provides the first piece of electrophysiological evidence supporting a recent interference resolution model based on localization data [Jonides, J., Nee, D.E., 2006. Brain mechanisms of proactive interference in working memory. Neuroscience 139, 181-193].

Genetics of Leaf Rust Resistance in Brambling Wheat

The CIMMYT-developed spring wheat 'Brambling' has a high level of adult-plant resistance (APR) to leaf rust caused by Puccinia triticina. Our objectives were to determine the genetic basis of resistance in seedlings and adult plants and the magnitude of genotype × environment effects on the expression of APR. Brambling was crossed with spring wheat 'Jupateco 73S' that is highly susceptible to current predominant P. triticina races in Mexico and the United States. The F₁, F_2:3, F_4:5, F_4:6, and F_5:7 recombinant inbred lines (RILs) were evaluated under artificial field epidemics in Mexico and St. Paul, MN. The RILs also were tested with five races of P. triticina in greenhouse seedling experiments. A DNA marker was used to postulate the presence of slow-rusting gene Lr34 in the RILs. F₁ data suggested strong dominant effect of the APR genes in Brambling. The proportion of homozygous susceptible lines in each generation indicated the presence of three effective resistance genes in adult plants of Brambling in tests in Mexico and three or four genes in tests in St. Paul. The RILs segregated for seedling genes Lr14a and Lr23 and adult-plant slow-rusting gene Lr34 derived from Brambling and Lr17a from Jupateco 73S. Gene Lr23 conditioned APR to P. triticina races present in the St. Paul nursery and accounted for the additional effective gene at this location. Expression of APR was influenced by the environment in the RILs, even though Brambling displayed a consistent response, indicating that stability of APR can be achieved by combinations of slow-rusting resistance genes.

Working memory selection and competition between target and distractor representations

A working memory selection task combining directed-forgetting and memory-scanning paradigms was used to test the hypothesis that difficulty in selecting target from distractor items in working memory depends on the competition between target and distractor representations, as is commonly assumed in perceptual selection research. Participants memorized two trigrams and were then cued to select one as the new memory set and forget the other. They later saw a test letter and made judgment as to whether the letter was in the selected trigram, i.e., the new memory set. Selection difficulty was examined by manipulating the type of selection cues and the time the cue could be utilized. While re-presenting the targets in the cue display facilitated selection, re-presenting distractors did not impede selection. The results suggest that working memory selection may depend more on the activation from representations of the target than of the distractor.

Varicella among adults: data from an active surveillance project, 1995-2005

We report detailed population-based data on varicella among adults. In 2 US varicella active surveillance sites with high vaccine coverage among young children, the incidence of varicella among adults declined 74% during 1995-2005. A low proportion (3%) of adults with varicella had been vaccinated, with no improvement over the decade of program implementation, suggesting that the decline was likely secondary to herd-immunity effects. Compared with children, adults had more severe varicella in terms of both clinical presentation and frequency of complications. However, <30% of adults with varicella were treated with acyclovir. Among adolescents, illness severity was intermediate between that in children and adults. Varicella cases are preventable through vaccination. As we enter the second decade of the varicella vaccination program in the United States, we need to ensure that susceptible adolescents and adults are adequately protected from varicella by vaccination and that those who acquire varicella are appropriately treated with effective antiviral treatment.

Changing varicella epidemiology in active surveillance sites--United States, 1995-2005

Significant reductions in varicella incidence were reported from 1995 to 2000 in the varicella active surveillance sites of Antelope Valley (AV), California, and West Philadelphia (WP), Pennsylvania. We examined incidence rates, median age, and vaccination status of case patients for 1995-2005. Coverage data were from the National Immunization Survey. By 2005, coverage among children 19-35 months of age reached 92% (AV) and 94% (WP); 57% and 64% of case patients in AV and WP, respectively, were vaccinated; and varicella incidence declined by 89.8% in AV and 90.4% in WP. Incidence declined in all age groups, especially among children <10 years of age in both sites and among adolescents 10-14 years of age in WP. In AV, since 2000, the incidence among adolescents 10-14 and 15-19 years of age increased. Implementation of school requirements through 10th grade in WP may explain the differences in the decline in incidence among adolescents. Continued surveillance will be important to monitor the impact that the 2-dose vaccine policy in children has on varicella epidemiology.