Online Drift Compensation for Chemical Sensors Using Estimation Theory

Sensor drift from slowly changing environmental conditions and other instabilities can greatly degrade a chemical sensor\u27s performance, resulting in poor identification and analyte quantification. In the present work, estimation theory (i.e., various forms of the Kalman filter) is used for online compensation of baseline drift in the response of chemical sensors. Two different cases, which depend on the knowledge of the characteristics of the sensor system, are studied. First, an unknown input is considered, which represents the practical case of analyte detection and quantification. Then, the more general case, in which the sensor parameters and the input are both unknown, is studied. The techniques are applied to simulated sensor data, for which the true baseline and response are known, and to actual liquid-phase SH-SAW sensor data measured during the detection of organophosphates. It is shown that the technique is capable of estimating the baseline signal and recovering the true sensor signal due only to the presence of the analyte. This is true even when the baseline drift changes rate or direction during the detection process or when the analyte is not completely flushed from the system

The influence of blanching, anti-browning agent and processing time on some physico-chemical properties and appearance of green peppers (Capsicum sinensis) during canning

Central Composite Rotatable Design (CCRD) was used to generate twenty combinations of these factors: blanching time, processing time and sodium metabisulphite concentration. The optimized conditions were then adapted for the canning process of green pepper. Blanching time ranged from 0-1 min whereas processing time and sodium metabisulphite concentration ranged from 10-30 min and 0-0.2%, respectively. The canned products were analyzed for physico-chemical qualities using standard analytical methods. Results obtained from various physico-chemical analyses showed variable trends and influences of the linear, quadratic and exponential interactions on the measured quality indices such as pH of the drained liquid, drained weight of the canned product, leached solids and colour of the canned products. The results showed significant (p.0.05) quadratic effect of sodium metabisulphite as well as linear effect of blanching time on the drained weight of the canned green pepper. Generally, the pH of the medium decreased (increased acidity) with increasing processing time, which was also positively associated with the extent or amount of leaching. Additionally, all three factors were observed to have affected (to variable extent) the colour of the canned products. Blanching and processing times also affected the degree of browning. There was a strong significant (p.0.05) influence of the quadratic factors of blanching time, processing time and sodium metabisulphite concentration on the colour properties (a-values, b-values and L-values) of the canned products. Statistical analysis showed significant (p.0.05) linear effects of blanching time and sodium salt concentration as well as the combined effect of both factors on all the colour properties. All the studied parameters had significant  regression coefficients (p.0.05) suggesting the studied parameters  contributed significantly to the observed changes. Colour of the canned  products changed from green toward redness with increasing blanching time at all concentrations of sodium metabisulphite. Optimal processing  combination of 0 min blanching time, 10 min processing time and sodium metabisulphite concentration of 0.2% produced a highly acceptable canned pepper product with preferred physico-chemical and appearance properties.Key words: Canning, pepper, blanching, antibrowning agent

Roasting effects on phenolic content and free-radical scavenging activities of pulp preconditioned and fermented cocoa (Theobroma cacao) beans

Polyphenols are phytochemicals responsible for the astringency, bitterness, green flavours and antioxidant activities in Theobroma cacao beans. Polyphenols degradation in cocoa beans during roasting is crucial to the flavour outcome and it is influenced by factors such as temperature, time and pod storage. Antioxidants are compounds that help to inhibit oxidation reactions caused by free radicals such as singlet oxygen, superoxide, peroxyl radicals, hydroxyl radicals and peroxynitrite thereby preventing damage to the cells and tissues. Their mechanisms of action include scavenging reactive oxygen and decreasing localised oxygen concentration thereby reducing molecular oxygen’s oxidation potential, metabolising lipid peroxides to non-radical products and chelating metal ions to prevent generation of free radicals in humans. The study aimed at investigating changes in total polyphenols, anthocyanins, o-diphenols and antioxidant activity (free-radical scavenging activities) after roasting of pulp preconditioned and fermented cocoa beans using standard analytical methods. A 4×4 full factorial design with the principal experimental factors as pod storage time (0, 3, 7 and 10 days) and roasting duration (0, 15, 30 and 45 minutes) at 120oC were used to study the changes in the total polyphenols, anthocyanins, o-diphenols and % free-radical scavenging activities of the cocoa beans. Variable decrease in total polyphenols, odiphenols and anthocyanins were observed with increase in pre-conditioning (pod storage time) and roasting duration. However, variable trends were observed for the % free-radical scavenging activities. The total polyphenols, anthocyanins and o-diphenols in the cocoa beans after 45 minutes roasting decreased in the range 132.24 to 57.17 mg/g, 6.71 to 1.07 mg/kg and 15.94 to 8.25 mg/g respectively at all pod storage treatments. The total polyphenols of the fermented, dried and unstored (freshly harvested) cocoa beans was 132.25 mg/g which reduced to 122.14 mg/g (7.6% degradation), 116.721 mg/g (11.7% degradation) and 92.22 mg/g (30.3% degradation) after storage for 3, 7 and 10 days, respectively. The optimum decrease in the % freeradical scavenging activity was 7 days and above of pods storage. Increasing roasting time caused a continuous decrease in the % free-radical scavenging activity from 89.10% to 74.31% after 45 minutes for beans from the unstored (freshly harvested) pods. However, pod storage caused an increase in the % free radical scavenging activities during roasting. Pulp pre-conditioning (pod storage) and roasting duration could be used to reduce the astringency and bitterness caused by polyphenols, o-diphenols and anthocyanins in cocoa beans as well as increase the antioxidant activity imparted by cocoa.Key words: Cocoa, pod storage, roasting, polyphenols

Organic nitrate and secondary organic aerosol yield from NO3 oxidation of ß-pinene evaluated using a gas-phase kinetics/aerosol partitioning model

The yields of organic nitrates and of secondary organic aerosol (SOA) particle formation were measured for the reaction NO3+beta-pinene under dry and humid conditions in the atmosphere simulation chamber SAPHIR at Research Center Julich. These experiments were conducted at low concentrations of NO3 (NO3+N2O5 < 10 ppb) and beta-pinene (peak similar to 15 ppb), with no seed aerosol. SOA formation was observed to be prompt and substantial (similar to 50% mass yield under both dry conditions and at 60% RH), and highly correlated with organic nitrate formation. The observed gas/aerosol partitioning of organic nitrates can be simulated using an absorptive partitioning model to derive an estimated vapor pressure of the condensing nitrate species of p(vap) similar to 5x10(-6) Torr (6.67x10(-4) Pa), which constrains speculation about the oxidation mechanism and chemical identity of the organic nitrate. Once formed the SOA in this system continues to evolve, resulting in measurable aerosol volume decrease with time. The observations of high aerosol yield from NOx-dependent oxidation of monoterpenes provide an example of a significant anthropogenic source of SOA from biogenic hydrocarbon precursors. Estimates of the NO3+beta-pinene SOA source strength for California and the globe indicate that NO3 reactions with monoterpenes are likely an important source (0.5-8% of the global total) of organic aerosol on regional and global scales

Community perspectives of complex trauma assessment for Aboriginal parents: 'Its important, but how these discussions are held is critical'

Background and Purpose: Becoming a parent can be an exciting and also challenging transition, particularly for parents who have experienced significant hurt in their own childhoods, and may be experiencing ‘complex trauma.’ Aboriginal and Torres Strait Islander (Aboriginal) people also experience historical trauma. While the parenting transition is an important time to offer support for parents, it is essential to ensure that the benefits of identifying parents experiencing complex trauma outweigh any risks (e.g., stigmatization). This paper describes views of predominantly Aboriginal stakeholders regarding (1) the relative importance of domains proposed for complex trauma assessment, and (2) how to conduct these sensitive discussions with Aboriginal parents. Setting and Methods: A co-design workshop was held in Alice Springs (Central Australia) as part of an Aboriginal-led community-based participatory action research project. Workshop participants were 57 predominantly Aboriginal stakeholders with expertise in community, clinical, policy and academic settings. Twelve domains of complex trauma-related distress had been identified in existing assessment tools and through community consultation. Using story-telling and strategies to create safety for discussing complex and sensitive issues, and delphi-style methods, stakeholders rated the level of importance of the 12 domains; and discussed why, by whom, where and how experiences of complex trauma should be explored. Main Findings: The majority of stakeholders supported the importance of assessing each of the proposed complex trauma domains with Aboriginal parents. However, strong concerns were expressed regarding where, by whom and how this should occur. There was greater emphasis and consistency regarding ‘qualities’ (e.g., caring), rather than specific ‘attributes’ (e.g., clinician). Six critical overarching themes emerged: ensuring emotional and cultural safety; establishing relationships and trust; having capacity to respond appropriately and access support; incorporating less direct cultural communication methods (e.g., yarning, dadirri); using strengths-based approaches and offering choices to empower parents; and showing respect, caring and compassion. Conclusion: Assessments to identify Aboriginal parents experiencing complex trauma should only be considered when the prerequisites of safety, trusting relationships, respect, compassion, adequate care, and capacity to respond are assured. Offering choices and cultural and strengths-based approaches are also critical. Without this assurance, there are serious concerns that harms may outweigh any benefits for Aboriginal parents

CALCULATION OF INTERFACIAL TENSIONS BETWEEN MACROMOLECULAR SOLUTIONS AND SOLTROL-130 FROM CONTACT ANGLES MEASUREMENTS

ABSTRACT The determination of the surface tension of some liquids or solutions has been carried out using a tensiometer. The determination of the contact angle between the liquids and a planar surface has also been carried out using photography. Polar and dispersive contributions of the surface tension were obtained by calculation while the polarities of the liquids and solutions were determined applying Wu equations. This method gave the different results for solutions prepared from macromolecular compounds (acroleine -ethanolamine macromolecular solution 1g/l, acroleinediethanolamine macromolecular solution 1g/l, polyglutaraldehyde-ethanolamine macromolecular solution 0.7 g/l and polyglutaraldehyde -diethanolamine macromolecular solution 1 g/l) synthesized by Malonda from glutaraldehyde and acroleine. The dispersive and polar contributions of the surface tension were computed and used to calculate the interfacial tensions of solutions by the simple measurement of the contact angle. The results have revealed that the computed interfacial tensions were comparable to the values measured directly by the tensiometer for polyglutaraldehydeethanolamine macromolecular solution 0.7 g/l and polyglutaraldehyde -diethanolamine macromolecular solution 1 g/l) making an interface with Soltrol-130 of 17.1 and 16.9 dynes/cm compared to direct measured values of 17.2 and 17.7 dynes/cm respectively representing 1% and 5% error, respectively

Parenting after a history of childhood maltreatment: a scoping review and map of evidence in the perinatal period

BACKGROUND AND AIMS:Child maltreatment is a global health priority affecting up to half of all children worldwide, with profound and ongoing impacts on physical, social and emotional wellbeing. The perinatal period (pregnancy to two years postpartum) is critical for parents with a history of childhood maltreatment. Parents may experience 'triggering' of trauma responses during perinatal care or caring for their distressed infant. The long-lasting relational effects may impede the capacity of parents to nurture their children and lead to intergenerational cycles of trauma. Conversely, the perinatal period offers a unique life-course opportunity for parental healing and prevention of child maltreatment. This scoping review aims to map perinatal evidence regarding theories, intergenerational pathways, parents' views, interventions and measurement tools involving parents with a history of maltreatment in their own childhoods. METHODS AND RESULTS:We searched Medline, Psychinfo, Cinahl and Embase to 30/11/2016. We screened 6701 articles and included 55 studies (74 articles) involving more than 20,000 parents. Most studies were conducted in the United States (42/55) and involved mothers only (43/55). Theoretical constructs include: attachment, social learning, relational-developmental systems, family-systems and anger theories; 'hidden trauma', resilience, post-traumatic growth; and 'Child Sexual Assault Healing' and socioecological models. Observational studies illustrate sociodemographic and mental health protective and risk factors that mediate/moderate intergenerational pathways to parental and child wellbeing. Qualitative studies provide rich descriptions of parental experiences and views about healing strategies and support. We found no specific perinatal interventions for parents with childhood maltreatment histories. However, several parenting interventions included elements which address parental history, and these reported positive effects on parent wellbeing. We found twenty-two assessment tools for identifying parental childhood maltreatment history or impact. CONCLUSIONS:Perinatal evidence is available to inform development of strategies to support parents with a history of child maltreatment. However, there is a paucity of applied evidence and evidence involving fathers and Indigenous parents.Catherine Chamberlain, Graham Gee, Stephen Harfield, Sandra Campbell, Sue Brennan, Yvonne Clark, Fiona Mensah, Kerry Arabena, Helen Herrman, Stephanie Brown, for the ‘Healing the Past by Nurturing the Future’ grou

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London