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Our research focuses on developing environmentally friendly biodegradable ultrafiltration (UF) membranes for small-scale water purification in areas lacking infrastructure or during emergencies. To address biofouling challenges without resorting to harmful chemicals, we incorporate bio-based extracts, such as methyl gallate from A. occidentale leaves, a Malaysian ulam herb, known for its quorum sensing inhibition (QSI) properties. The methyl gallate enriched extract was purified by solvent partitioning and integrated into cellulose-based UF membranes (0 to 7.5% w w-1) through phase inversion technique. The resulting membranes exhibited enhanced anti-organic fouling and anti-biofouling properties, with flux recovery ratio (FRR) of 87.84 ± 2.00% against bovine serum albumin and FRRs of 76.67 ± 1.89% and 69.57 ± 1.77% against E. coli and S. aureus, respectively. The CA/MG-5 membrane showed a 224% improvement in pure water flux (PWF) compared to the neat CA membrane. Our innovative approach significantly improves PWF, presenting an environmentally friendly method for biofouling prevention in UF membrane applications.
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Anacardium , Incrustaciones Biológicas , Escherichia coli , Membranas Artificiales , Extractos Vegetales , Ultrafiltración , Purificación del Agua , Incrustaciones Biológicas/prevención & control , Ultrafiltración/métodos , Extractos Vegetales/farmacología , Extractos Vegetales/química , Escherichia coli/efectos de los fármacos , Anacardium/química , Purificación del Agua/métodos , Staphylococcus aureus/efectos de los fármacos , Ácido Gálico/análogos & derivados , Ácido Gálico/farmacología , Ácido Gálico/química , Albúmina Sérica Bovina/químicaRESUMEN
BACKGROUND: Perinatal maternal depression may affect fetal neurodevelopment directly or indirectly via exposures such as smoking, alcohol, or antidepressant use. The relative contribution of these risk factors on child executive function (EF) has not been explored systematically. METHODS: A prospective pregnancy cohort of 197 women and their children was studied to determine whether maternal depression diagnosis and the trajectory of maternal depressive symptoms (MDSs) from early pregnancy to 12 months postpartum predicts child EF at age 4 (measured using the preschool age psychiatric assessment, NEPSY-II, and Shape School task) using latent growth curve modeling. Indirect effects of smoking, alcohol, and antidepressant use were also formally tested. RESULTS: Increasing maternal perinatal depressive symptoms over time predicted more inattentive symptoms, poorer switching, and motor inhibition, but not cognitive inhibition. When adjusted for multiple comparison, and after accounting for maternal cognition and education, the association with child inattentive symptoms remained significant. However, diagnosed depression did not predict child EF outcomes. Prenatal exposure to smoking, alcohol, and antidepressants also did not mediate pathways from depressive symptoms to EF outcomes. Our findings were limited by sample size and statistical power to detect outcome effects of smaller effect size. CONCLUSIONS: This study suggests that increasing MDSs over the perinatal period is associated with poorer EF outcomes in children at age 4 - independent of prenatal smoking, drinking, or antidepressant use. Depressive chronicity, severity, and postpartum influences may play crucial roles in determining childhood outcomes of EF.
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Depresión Posparto , Depresión , Niño , Embarazo , Preescolar , Humanos , Femenino , Función Ejecutiva/fisiología , Estudios Prospectivos , Fumar , Madres/psicología , Antidepresivos , Depresión Posparto/epidemiología , Depresión Posparto/psicologíaRESUMEN
This work demonstrates oscillation frequency modulation in a NbO2-based relaxation oscillator device, in which the oscillation frequency increases with operating temperature and source voltage, and decreases with load resistance. An annealing-induced oxygen diffusion at 373 K was carried out to optimize the stoichiometry of the bulk NbO2to achieve consistent oscillation frequency shift with device temperature. The device exhibits stable self-sustained oscillation in which the frequency can be modulated between 2 and 33 MHz, and a wider operating voltage range can be obtained. An additional surface treatment step was employed during fabrication to reduce the surface roughness of the bottom electrode and to remove surface contaminants that affect the interfacial properties of the device. The device frequency tunability coupled with high oscillating frequency and high endurance capability of more than 1.5 × 108cycles indicates that the Pt/NbO2/Pt device is particularly suitable for applications in an oscillatory neural network.
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BACKGROUND: The development of childhood anxiety disorders (CADs) is likely to depend on pathways that can be programmed by early-life risk factors. We test the hypothesis that early-life maternal factors can predict this programming effect on CAD. METHODS: Data were obtained from 198 women and children from the Mercy Pregnancy and Emotional Wellbeing Study (MPEWS), a cohort study with data collected across pregnancy, postpartum and until 4 years of age. Maternal antenatal depression was measured using the Structured Clinical Interview for DSM-IV (SCID-IV), together with antenatal hair cortisol concentrations, maternal childhood trauma and parenting stress at 6 months postpartum. CAD was assessed with the Preschool Age Psychiatric Assessment and the Child Behaviour Checklist. RESULTS: Antenatal depression, a history of maternal childhood trauma and lower gestational age at birth were each associated with anxiety disorders at 4 years of age in their children. A multivariate binary logistic model with these early predictors explained approximately 9% of variance in CAD outcome at 4 years of age; however, only maternal trauma and gestational age were significant predictors in the model. The effect of early parenting stress on CAD was found to vary by the concentration of maternal antenatal hair cortisol, whereby postpartum parenting stress was associated with CAD only when there were higher maternal antenatal cortisol levels. CONCLUSIONS: This study suggests the importance of maternal factors pre-conception, pregnancy and in the postnatal period, which predict CADs and this is consistent with a developmental programming hypothesis for CAD.
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Depresión Posparto , Trastorno Depresivo , Complicaciones del Embarazo , Ansiedad , Trastornos de Ansiedad/epidemiología , Trastornos de Ansiedad/psicología , Niño , Preescolar , Estudios de Cohortes , Depresión/psicología , Trastorno Depresivo/psicología , Femenino , Humanos , Recién Nacido , Madres/psicología , Responsabilidad Parental/psicología , Embarazo , Complicaciones del Embarazo/epidemiología , Complicaciones del Embarazo/psicologíaRESUMEN
Prader-Willi Syndrome (PWS) is a rare genetic disorder associated with emotional/behavioral disturbances. These difficulties are well documented in the literature, but the positive attributes of these individuals are not described. Taking a strengths-based approach, the aim of this study was to describe the emotional/behavioral strengths and difficulties in children and young people with PWS from their parent caregivers' perspectives. Parent caregivers of 52 individuals with PWS aged 4-24 years (median = 12.1 years; including 22 males) completed the parent form of the Developmental Behavior Checklist (DBC-P), including its original two open-ended questions regarding positive traits. Prevalences of emotional/behavioral disturbances were comparable to those reported in previous literature: common behaviors of concern across studies being skin-picking (75%), impulsivity (69%), poor sense of danger (67%), lying (67%), and tantrums (54%). Total DBC-P scores showed that just over half (n = 28, 54%) had scores indicative of clinically significant behavior problems. However, thematic analysis of caregivers' written comments regarding their children's strengths resolved into three themes: warmth (94%), persistence (41%), and skills (41%). Warmth encompassed friendliness, happiness, and empathy. A strength-based approach to behavioral difficulties in PWS provides a more balanced view of the children and a more holistic foundation for interventions.
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Trastornos Mentales , Síndrome de Prader-Willi , Problema de Conducta , Adolescente , Cuidadores , Niño , Emociones , Humanos , Masculino , Síndrome de Prader-Willi/epidemiología , Síndrome de Prader-Willi/genéticaRESUMEN
BACKGROUND: The impact of COVID-19 (SARS-CoV-2) pandemic school lockdowns on the mental health problems and feelings of loneliness of adolescents with neurodevelopmental disorders (NDDs) is hypothesized to be greater than that of their non-NDD peers. This two and a half year longitudinal study compared changes in the mental health and loneliness of Western Australian adolescents pre-COVID-19 (November 2018 and April 2019), immediately prior to COVID-19 school lockdowns (March 2020), and post schools reopening (July/August 2020). METHODS: An age-and-gender matched sample of 476 adolescents with-or-without NDDs completed online assessments for mental health and loneliness. RESULTS: Adolescents with NDDs reported elevated levels of adverse mental health across all four waves of data collection. These young people experienced little change in mental health problems and feelings of loneliness over time, and any increase during school lockdowns returned to, or fell below pre-COVID-19 levels once schools reopened. In comparison, adolescents without NDDs experienced significant increases from a low baseline in depression symptoms, externalizing symptoms, feelings of isolation, and having a positive attitude to being alone, and evidenced a significant decline in positive mental wellbeing. Quality of friendships were unaffected by COVID-19 school lockdowns for all adolescents regardless of NDD status. Of the adolescents with NDDs, those with Attention-Deficit/Hyperactivity Disorder reported a significant increase in positive mental wellbeing following school lockdowns. CONCLUSIONS: Adolescents with NDDs emerged relatively unscathed from COVID-19 school lockdowns and the short term impacts associated with these were not maintained over time. These findings should be considered in the context of this study's geographical location and the unpredictability of school lockdowns. Learning to live with school lockdowns into the future may be a critical element for further investigation in the context of interventions.
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COVID-19 , Trastornos del Neurodesarrollo , Adolescente , Humanos , Preescolar , Salud Mental , Soledad/psicología , Estudios Longitudinales , SARS-CoV-2 , Australia/epidemiología , Control de Enfermedades Transmisibles , Instituciones AcadémicasRESUMEN
The study used regularized partial correlation network analysis (EBICglasso) to examine the structure of DSM-5 internet gaming disorder (IGD) symptoms (network 1); and the associations of the IGD symptoms in the network with different types of motivation as defined in the self-determination theory i.e., intrinsic motivation (engaging in an activity for something unrelated to the activity), identified regulation (engaging in the activity because it aligns with one's values and/or goals), external regulation (engagement in activity being driven by external rewards and/or approval), and amotivation (engaging in an activity without often understanding why) (network 2). Participants were 968 adults from the general community. They completed self-rating questionnaires covering IGD symptoms and different types of motivation. The findings for network 1 showed mostly positive connections between the symptoms within the IGD network. The most central symptom was loss of control, followed by continuation, withdrawal symptoms, and tolerance. In general, these symptoms were more strongly connected with each other than with the rest of the IGD symptoms. The findings for network 2 showed that the different types of motivation were connected differently with the different IGD symptoms. For instance, the likeliest motivation for the preoccupation and escape symptoms is intrinsic motivation, and for negative consequences, it is low identified regulation. Overall, the findings showed a novel understanding of the structure of the IGD symptoms, and the motivations underlying them. The clinical implications of the findings for assessment and treatment of IGD are discussed.
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Trastorno de Adicción a Internet , Motivación , Adulto , Humanos , Trastorno de Adicción a Internet/diagnóstico , Autonomía Personal , RecompensaRESUMEN
Individuals with Prader-Willi syndrome (PWS) often have excessive daytime sleepiness and emotional/behavioral disturbances. The objective of this study was to examine whether daytime sleepiness was associated with these emotional/behavioral problems, independent of nighttime sleep-disordered breathing, or the duration of sleep. Caregivers of individuals with PWS (aged 3 to 25 years) completed the Pediatric Sleep Questionnaire (PSQ), Epworth Sleepiness Scale for Children and Adolescents (ESS-CHAD), and the parent version of the Developmental Behavior Checklist (DBC-P). Sleep adequacy was adjusted for age by computing sleep duration against age-specific recommendations. The associations between ESS-CHAD and the total DBC and its subscale scores were evaluated by linear regression, adjusted for sleep-related breathing difficulties, sleep adequacy, and body mass index (BMI). There were 54 responses for individuals with PWS (including 22 males) aged 4.4-24.0 (mean 12.5) years. Daytime sleepiness predicted a substantial proportion of the variance in total DBC-P scores in the unadjusted model (28%; ß = 0.028; p < 0.001) and when adjusted for sleep adequacy, BMI, and sleep-related breathing difficulties (29%; ß = 0.023; p = 0.007). This relationship was not moderated by BMI Z-scores, but the relationship was more prominent for children younger than 12 years than for children older than 12 years.Conclusions: These findings provide preliminary novel evidence that daytime sleepiness may drive the expression of emotional/behavioral disturbances, and should be explored as a potential modifiable risk factor for these disturbances in PWS, particularly pre-adolescent children.
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Trastornos de Somnolencia Excesiva , Síndrome de Prader-Willi , Problema de Conducta , Adolescente , Niño , Trastornos de Somnolencia Excesiva/complicaciones , Emociones , Humanos , Masculino , Síndrome de Prader-Willi/complicaciones , SueñoRESUMEN
BACKGROUND: Consistent research findings indicate that parents and teachers observe genuinely different Attention Deficit/Hyperactivity Disorder (ADHD) behaviours in their respective settings. OBJECTIVE: To evaluate the utility of information provided by teacher informant assessments (INFAs) of ADHD symptoms, and the implications of aggregation algorithms in combing parents' information, i.e. using 'or-rule' (endorsement by either one informant) versus 'and-rule' (endorsement by both informants). METHOD: Teacher ratings on Conners scales and clinical data from parental accounts on 1383 probands and their siblings from the IMAGE study were analysed. The psychometric properties of teacher and combined ratings using the item response theory model (IRT) are presented. Kappa coefficients, intraclass correlations and linear regression were employed. RESULTS: First, teacher endorsement of symptoms is located in a narrow part of the trait continuum close to the average levels. Symptoms exhibit comparable perception in the measurement of the trait(s) with similar discrimination ability and information (reliability). Second, the IRT properties of the 'or-rule' ratings are predominantly influenced by parent-INFAs; and the 'and-rule' ratings predominantly by teacher-INFAs ratings. Third, parent-teacher INFAs agreement was low, both for individual items (κ = 0.01-0.15) and for dimensional scores (r = 0.12-0.16). The 'or-rule' captured milder expressions of ADHD symptoms, whereas the 'and-rule' indexed greater severity of ADHD. CONCLUSIONS: Parent and teacher-INFAs provide different kinds of information, while both are useful. Teacher-INFA and the 'and-rule' provide a more accurate index of severity than an additive symptom count. Parent-INFA and the 'or-rule' are more sensitive for detecting cases with milder ADHD.
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Trastorno por Déficit de Atención con Hiperactividad/diagnóstico , Padres/psicología , Psicometría/métodos , Maestros/psicología , Femenino , Humanos , Masculino , Reproducibilidad de los ResultadosRESUMEN
Undesired browning reaction catalyzed by polyphenol oxidase (PPO) has reduced the nutritional quality and customer acceptance of the products. The inhibitory effects of six coastal plants including Sonneratia alba, Rhizophora apiculata, Syzygium grande, Rhizophora mucronata, Hibiscus tiliaceus and Bruguiera gymnorhiza on PPO in banana, sweet potato and ginger were studied based on oxidation of pyrocatechol. Banana exhibited the highest PPO activity (141,600 U), followed by sweet potato (43,440 U) and ginger (26,880 U). Banana PPO was strongly inhibited by R. apiculata (70.87%) and sweet potato PPO was strongly inhibited by S. alba (82.00%). In general, most banana PPO was the most susceptible to inhibition with all inhibitors having inhibition higher than 60.00% at 0.5 mg/ml and ginger PPO was the least susceptible with all inhibitors showing less than 50.00% inhibition at 0.5 mg/ml. Coastal plant extracts are potentially to be developed as natural inhibitors for preventing enzymatic browning of fruits and vegetables.
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BACKGROUND: Children and adolescents with intellectual disability are at risk of developing psychiatric symptoms and disorders; yet, the estimates reported in the literature have been inconsistent, presenting a potential barrier for service planning and delivery. Sources of variability could arise from differences in measurement instruments as well as subgroup membership by severity of intellectual disability, gender and age. This systematic review aimed to address these gaps. METHOD: MEDLINE and PsycINFO databases were searched from inception to 2018 and selected studies were reviewed. Studies were included if they reported point prevalence estimates of mental health symptomology or diagnoses in a general population of 6- to 21-year-old individuals with intellectual disability. The Joanna Briggs Institute Prevalence Critical Appraisal Checklist was applied to eligible papers to appraise their scientific strength. Pooled prevalence for mental health symptomology was determined using a random-effects meta-analysis. RESULTS: A total of 19 studies were included, including 6151 children and adolescents. The pooled prevalence estimate captured by the Developmental Behaviour Checklist was 38% (95% confidence interval = [31, 46]), contrasting with 49% (95% confidence interval = [46, 51]) captured by the Child Behaviour Checklist; both rates were higher than a non-intellectual disability population. Severity of intellectual disability did not significantly influence the Developmental Behaviour Checklist risks. Insufficient data were available to conduct statistical analyses on the effects of age, gender and socioeconomic status. Of diagnosed psychiatric disorders, attention deficit/hyperactivity disorder (30%), conduct disorder (3-21%) and anxiety disorders (7-34%) were the most prevalent conditions. CONCLUSION: This review consists of the largest sample hitherto evaluated. In the intellectual disability population, mental health comorbidities could be better detected by a symptom phenotype than a psychiatric diagnostic phenotype. Crucially, future research needs to address the effect of measurement validity in the intellectual disability population. Estimated prevalence rates were high compared to the general population, indicating the importance of systematic screening, case detection and appropriate management.
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Discapacidad Intelectual , Adolescente , Adulto , Trastornos de Ansiedad , Niño , Comorbilidad , Humanos , Discapacidad Intelectual/epidemiología , Salud Mental , Prevalencia , Adulto JovenRESUMEN
OBJECTIVE: There is ongoing uncertainty about the structure and definition of alexithymia. Conceptually, alexithymia has traditionally been defined as a multidimensional trait with four components: difficulty identifying feelings, difficulty describing feelings, externally orientated thinking, and difficulty fantasizing. However, some authors suggest that difficulty fantasizing might not be a component, and others suggest low emotional reactivity is a fifth component. In this study, we sought to clarify this issue using factor analysis. METHOD: In a sample of adults (N = 508), we administered a comprehensive battery of psychometric measures and analyzed their latent structure using exploratory factor analysis. RESULTS: Subscales assessing difficulty identifying feelings, difficulty describing feelings, and externally orientated thinking all loaded well together on the alexithymia factor. However, none of the subscales assessing aspects of difficulty fantasizing (i.e., daydreaming frequency, vividness, content, or use of daydreams to regulate emotions) loaded on the alexithymia factor. Similarly, no emotional reactivity subscales loaded on the alexithymia factor, and alexithymia was associated with higher (not lower) levels of emotional reactivity for negative emotions. CONCLUSIONS: Difficulty fantasizing and low emotional reactivity are not components of the latent alexithymia construct. The traditional four-component definition of alexithymia likely warrants refinement to a more parsimonious three-component solution.
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Síntomas Afectivos , Emociones , Adulto , Cognición , Análisis Factorial , Humanos , PsicometríaRESUMEN
AIMS: Up to 50% of children with attention deficit hyperactivity disorder (ADHD) also present with difficulties with motor proficiency. Several assessments of motor proficiency are available for occupational therapists, though the validity of these measures in an ADHD population requires further exploration. The aim of this paper was to evaluate the consistency of scores obtained using the long-form and short-form of the Bruininks-Oseretsky Test of Motor Proficiency-Second Edition (BOT-2) in a school-age ADHD sample. METHOD: The BOT-2 long-form was administered to 84 school-age children (78 males) with ADHD; short-form scores were extracted from the relevant long-form items. RESULTS: Long-form and short-form total scores were highly correlated (r = .87), though the average short-form score was significantly higher. As a categorical measure, 52 children were classified as "at-risk" for movement difficulties by the long-form; but only 36 by the short-form, yielding a false-negative rate of 30.77%. The sensitivity of short-form could be improved by raising the cut-off thresholds of short-form scores as identified by receiver operating characteristic curve analysis but did not yield practical utility. INTERPRETATION: As a continuous indicator (i.e. total scores), the short-form is comparable to the long-form. However, the short-form overestimates the child's motor proficiency relative to the long-form and yields an unacceptably high rate of false negatives as a categorical measure. The current revision of the short-form is therefore not recommended as a screening nor diagnostic instrument in an ADHD population. In the absence of ADHD-specific norms, use of the long-form provides greater opportunity for occupational therapists to identify those at-risk for movement difficulties. However, any assessment of motor proficiency should be accompanied by a broader comprehensive assessment to best understand a child's motor functioning.
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Trastorno por Déficit de Atención con Hiperactividad/complicaciones , Niños con Discapacidad/rehabilitación , Trastornos de la Destreza Motora/diagnóstico , Destreza Motora/fisiología , Encuestas y Cuestionarios/normas , Niño , Femenino , Humanos , Masculino , Trastornos de la Destreza Motora/etiología , Pruebas NeuropsicológicasRESUMEN
OBJECTIVES: Retrospective recall of dissociative symptoms has been found to mediate the association between childhood abuse and deliberate self-harm (DSH) in later life. To disentangle the effect of recall bias, we tested whether dissociation symptoms ascertained during an acute DSH presentation mediates this link. METHOD: All participants with DSH were recruited during emergency presentation. Seventy-one individuals aged 11-17 years with overdose (OD) and/or self-injury (SI) participated in semi-structured interviews and psychiatric assessment to measure abuse and dissociation. An age- and gender-matched comparison group of 42 non-psychiatric patients admitted to the same service were also assessed. RESULTS: The DSH groups reported significantly higher levels of abuse and dissociation compared to comparison group. Dissociation significantly mediated the association between abuse and DSH. Of the four dissociation subtypes, 'depersonalisation' was the primary mediator. Adolescents with chronic patterns of DSH and the 'OD + SI' self-harm type reported more severe dissociation. CONCLUSION: Exposure to abuse significantly increased the risk of DSH in adolescence. This association was mediated by dissociation. Our findings suggest a possible dose-response relationship between dissociation with DSH chronicity and the 'OD + SI' self-harm type, implicating the importance of evaluating dissociation and depersonalisation symptoms as well as abuse exposure in DSH management.
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Maltrato a los Niños/estadística & datos numéricos , Trastornos Disociativos/epidemiología , Sobredosis de Droga/epidemiología , Conducta Autodestructiva/psicología , Adolescente , Estudios de Casos y Controles , Niño , Comorbilidad , Trastornos Disociativos/psicología , Femenino , Humanos , Masculino , Factores de Riesgo , Reino Unido/epidemiologíaRESUMEN
Food browning is undesirable as it causes deterioration in food quality and appearance. This phenomenon was related to polyphenol oxidase (PPO), which catalyzes conversion of phenolic compounds into o-quinones. The present work evaluated the use of chemical and natural anti-browning agents to prevent the browning of ginger PPO. Sodium metabisulfite (5 mM) is a better chemical inhibitor compared to l-cysteine and sodium chloride as 55.00% of ginger PPO inhibition was achieved. The percentage of inhibition increased as the concentration of anti-browning agents increases. The addition of heated onion, chili pepper and pineapple extracts exhibited a stronger inhibitory effect on ginger PPO than unheated extracts. Heated chili pepper extract was the best natural inhibitor found in this study and it inhibited the ginger PPO (47.97%) mixed-competitively. Natural anti-browning agents have potential to be used to control the browning of ginger as well as other vegetables and fruits.
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This paper presents the enzymatic liquefaction process for honey jackfruit optimized with Pectinex® Ultra SP-L and Celluclast® 1.5 L individually or in combinations at different concentrations (0-2.5% v/w) and incubation time (0-2.5 h). Treatment with combinations of enzymes showed a greater effect in the reduction of viscosity (83.9-98.8%) as compared to single enzyme treatment (64.8-87.3%). The best parameter for enzymatic liquefaction was obtained with 1.0% (v/w) Pectinex® Ultra SP-L and 0.5% (v/w) Celluclast® 1.5 L for 1.5 h. Spray drying process was carried out using different inlet temperatures (140-180 °C) and maltodextrin concentrations (10-30% w/w). Results indicated that the spray-dried honey jackfruit powder produced at 160 °C with 30% w/w maltodextrin gave the highest product yield (66.90%) with good powder qualities in terms of water activity, solubility, moisture content, hygroscopicity, color and bulk density. The spray-dried honey jackfruit powder could potentially be incorporated into various food products.
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In view of ICD-11 revision, we evaluate whether the 18 DSM-IV diagnostic items retained by DSM-5 could be further improved (i) in predicting ADHD 'caseness' and 'impairment' and (ii) discriminating ADHD without CD (ADHD - CD) cases from ADHD with CD (ADHD + CD) cases. In a multi-centre study sample consisting of 1497 ADHD probands and 291 unaffected subjects, 18 diagnostic items were examined for redundancy; then each item was evaluated for association with caseness, impairment and CD status using Classical Test Theory, Item-Response Theory and logistic regression methods. First, all 18 DSM-IV items contributed significantly and independently to the clinical diagnosis of ADHD. Second, not all the DSM-IV items carried equal weighting. "Often loses things", "forgetfulness" and "difficulty sustaining attention" mark severity for Inattentiveness (IA) items and "often unduly noisy", "exhibits a persistent pattern of restlessness", "leaves seat in class" and "often blurts out answers" for Hyperactivity/Impulsivity (HI) items. "Easily distracted", "inattentive to careless mistakes", "often interrupts" and "often fidgets" are associated with milder presentations. In the IA domain, "distracted" yields most information in the low-severity range of the latent trait, "careless" in the mid-severity range and "loses" in the high-severity range. In the HI domains, "interrupts" yields most information in the low-severity range and "motor" in the high-severity range. Third, all 18 items predicted impairment. Fourth, specific ADHD items are associated with ADHD + CD status. The DSM-IV diagnostic items were valid and not redundant; however, some carried more weight than others. All items were associated with impairment.
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Trastorno por Déficit de Atención con Hiperactividad/diagnóstico , Manual Diagnóstico y Estadístico de los Trastornos Mentales , Problema de Conducta/psicología , Comorbilidad , Femenino , Humanos , MasculinoRESUMEN
Helical membrane proteins generally have a hydrophobic nature, with apolar side chains comprising the majority of the transmembrane (TM) helices. However, whenever polar side chains are present in the TM domain, they often exert a crucial role in structural interactions with other polar residues, such as TM helix associations and oligomerization. Moreover, polar residues in the TM region also often participate in protein functions, such as the Schiff base bonding between Lys residues and retinal in rhodopsin-like membrane proteins. Although many studies have focused on these functional polar residues, our understanding of stand-alone polar residues that are energetically unfavored in TM helixes is limited. Here, we adopted bacteriorhodopsin (bR) as a model system and systematically mutated 17 of its apolar Leu or Phe residues to polar Asn. Stability measurements of the resulting mutants revealed that all of these polar substitutions reduced bR stability to various extents, and the extent of destabilization of each mutant bR is also correlated to different structural factors, such as the relative accessible surface area and membrane depth of the mutation site. Structural analyses of these Asn residues revealed that they form sidechain-to-backbone hydrogen bonds that alleviate the unfavorable energetics in hydrophobic and apolar surroundings. Our results indicate that membrane proteins are able to accommodate certain stand-alone polar residues in the TM region without disrupting overall structures.