Metallic Wood through Deep-Cell-Wall Metallization: Synthesis and Applications

Metallic wood combines the unique structural benefits of wood and the properties of metals and is thus promising for applications ranging from heat transfer to electromagnetic shielding to energy conversion. However, achieving metallic wood with full use of wood structural benefits such as anisotropy and multiscale porosity is challenging. A key reason is the limited mass transfer in bulk wood where fibers have closed ends. In this work, programmed removal of cell-wall components (delignification and hemicellulose extraction) was introduced to improve the accessibility of cell walls and mass diffusion in wood. Subsequent low-temperature electroless Cu plating resulted in a uniform continuous Cu coating on the cell wall, and, furthermore, Cu nanoparticles (NPs) insertion into the wood cell wall. A novel Cu NPs-embedded multilayered cell-wall structure was created. The unique structure benefits compressible metal-composite foam, appealing for stress sensors, where the multilayered cell wall contributes to the compressibility and stability. The technology developed for wood metallization here could be transferred to other functionalizations aimed at reaching fine structure in bulk wood.

Ultrastrong Ionotronic Films Showing Electrochemical Osmotic Actuation

A multifunctional soft material with high ionic and electrical conductivity, combined with high mechanical properties and the ability to change shape can enable bioinspired responsive devices and systems. The incorporation of all these characteristics in a single material is very challenging, as the improvement of one property tends to reduce other properties. Here, a nanocomposite film based on charged, high-aspect-ratio 1D flexible nanocellulose fibrils, and 2D Ti3 C2 Tx MXene is presented. The self-assembly process results in a stratified structure with the nanoparticles aligned in-plane, providing high ionotronic conductivity and mechanical strength, as well as large water uptake. In hydrogel form with 20 wt% liquid, the electrical conductivity is over 200 S cm-1 and the in-plane tensile strength is close to 100 MPa. This multifunctional performance results from the uniquely layered composite structure at nano- and mesoscales. A new type of electrical soft actuator is assembled where voltage as low as ±1 V resulted in osmotic effects and giant reversible out-of-plane swelling, reaching 85% strain.

Gradience Free Nanoinsertion of Fe3O4 into Wood for Enhanced Hydrovoltaic Energy Harvesting

Hydrovoltaic energy harvesting offers the potential to utilize enormous water energy for sustainable energy systems. Here, we report the utilization and tailoring of an intrinsic anisotropic 3D continuous microchannel structure from native wood for efficient hydrovoltaic energy harvesting by Fe3O4 nanoparticle insertion. Acetone-assisted precursor infiltration ensures the homogenous distribution of Fe ions for gradience-free Fe3O4 nanoparticle formation in wood. The Fe3O4/wood nanocomposites result in an open-circuit voltage of 63 mV and a power density of ∼52 μW/m2 (∼165 times higher than the original wood) under ambient conditions. The output voltage and power density are further increased to 1 V and ∼743 μW/m2 under 3 suns solar irradiation. The enhancement could be attributed to the increase of surface charge, nanoporosity, and photothermal effect from Fe3O4. The device exhibits a stable voltage of ∼1 V for 30 h (3 cycles of 10 h) showing good long-term stability. The methodology offers the potential for hierarchical organic-inorganic nanocomposite design for scalable and efficient ambient energy harvesting.

ZnO microrods sandwiched between layered CNF matrix: Fabrication, stress transfer, and mechanical properties

Functional metal oxide particles are often added to the polymers to prepare flexible functional polymer composites with adequate mechanical properties. ZnO and cellulose nanofibrils (CNF) outstand among these metal oxides and the polymer matrices respectively due to their various advantages. Herein, we in situ prepare ZnO microrods in the presence of CNF, which resultes in a layered composite structure. The ZnO microrods are sandwiched between the CNF layers and strongly bind to highly charged CNF, which provides a better stress transfer during mechanical activity. Digital image correction (DIC) and finite element analysis-based computational homogenization methods are used to investigate the relationship between mechanical properties and composite structure, and the stress transfer to the ZnO microrods. Full-field strain measurements in DIC reveal that the in situ ZnO microrods preparation leads to their homogenous distribution in the CNF matrix unlike other methods, which require external means such as ultrasonication. The computational homogenization technique provides a fairly good insight into the stress transfer between constituents in microstructure as well as a good prediction of macroscopic mechanical properties, which otherwise, would be challenging to be assessed by any ordinary mechanical testing in the layered composites. Finally, we also demonstrate that these composites could be used as physiological motion sensors for human health monitoring.

Aqueous synthesis of highly functional, hydrophobic, and chemically recyclable cellulose nanomaterials through oxime ligation

Cellulose nanofibril (CNF) materials are candidates for the sustainable development of high mechanical performance nanomaterials. Due to inherent hydrophilicity and limited functionality range, most applications require chemical modification of CNF. However, targeted transformations directly on CNF are cumbersome due to the propensity of CNF to aggregate in non-aqueous solvents at high concentrations, complicating the choice of suitable reagents and requiring tedious separations of the final product. This work addresses this challenge by developing a general, entirely water-based, and experimentally simple methodology for functionalizing CNF, providing aliphatic, allylic, propargylic, azobenzylic, and substituted benzylic functional groups. The first step is NaIO₄ oxidation to dialdehyde-CNF in the wet cake state, followed by oxime ligation with O-substituted hydroxylamines. The increased hydrolytic stability of oximes removes the need for reductive stabilization as often required for the analogous imines where aldehyde groups react with amines in water. Overall, the process provides a tailored degree of nanofibril functionalization (2-4.5 mmol/g) with the possible reversible detachment of the functionality under mildly acidic conditions, resulting in the reformation of dialdehyde CNF. The modified CNF materials were assessed for potential applications in green electronics and triboelectric nanogenerators.

Functionalized Wood Veneers as Vibration Sensors: Exploring Wood Piezoelectricity and Hierarchical Structure Effects

Functional wood materials often rely on active additives due to the weak piezoelectric response of wood itself. Here, we chemically modify wood to form functionalized, eco-friendly wood veneer for self-powered vibration sensors. Only the piezoelectricity of the cellulose microfibrils is used, where the drastic improvement comes only from molecular and nanoscale wood structure tuning. Sequential wood modifications (delignification, oxidation, and model fluorination) are performed, and effects on vibration sensing abilities are investigated. Wood veneer piezoelectricity is characterized by the piezoresponse force microscopy mode in atomic force microscopy. Delignification, oxidation, and model fluorination of wood-based sensors provide output voltages of 11.4, 23.2, and 60 mV by facilitating cellulose microfibril deformation. The vibration sensing ability correlates with improved piezoelectricity and increased cellulose deformation, most likely by large, local cell wall bending. This shows that nanostructural wood materials design can tailor the functional properties of wood devices with potential in sustainable nanotechnology.

Factors Associated with Disposable Menstrual Absorbent Use Among Young Women in India

CONTEXT

Hygienic use of absorbent products during menstruation is a challenge for young women in India, especially among the underprivileged, who lack knowledge and access to resources. Reuse of menstrual absorbents can be unhygienic and result in adverse health and other outcomes.

METHODS

Data from the 2015-2016 National Family Health Survey-4 for 233,606 menstruating women aged 15-24 were used to examine levels and correlates of exclusive use of disposable absorbents during menstruation. Bivariate and logistic regression analyses were conducted to identify disparities in exclusive use by such characteristics as caste, mass media exposure and interaction with health workers.

RESULTS

Exclusive use of disposable absorbents was low among young women overall (37%), and varied substantially by caste and other characteristics. Compared with women from general castes, those from scheduled castes, scheduled tribes and other backward classes had reduced odds of exclusive disposable absorbent use (odds ratios, 0.8-0.9). Disposable absorbent use was negatively associated with lower levels of education and household wealth, and rural residence. Compared with women who reported daily media exposure, those exposed less frequently had reduced odds of disposable absorbent use (0.7-0.9). Among those who recently met with a health worker, odds of use were lower if menstrual hygiene had not been discussed (0.9).

CONCLUSIONS

Promoting awareness of proper menstrual hygiene-through education, media campaigns and discussion with reproductive health workers-and targeted interventions to disseminate and subsidize the purchase of disposable sanitary napkins should be pursued to address health disparities.

Association between modern contraceptive use and child mortality in India: A calendar data analysis of the National Family Health Survey (2015-16)

Background

Influence of contraceptive use on increased gap between successive births and attributed reduced risk of child deaths is well documented in developing countries. However, there is scarcity of evidence on direct contribution of contraceptive use on child survival especially in Indian context.

Methods

Using information given in the reproductive calendar history of the National Family Health Survey of India conducted in 2015–16, this study examines the effect of modern contraceptive use on childhood mortality – infant mortality rate (IMR) and under-five mortality rate (U5MR). Bivariate analysis and cox proportional hazard model is applied in the study.

Results

Finding reveals that use of reversible contraceptives prior to birth resulted in low childhood mortality rates. IMR is 35 per 1000 live births among births with preceding use of modern reversible contraceptives as compared to 44 per 1000 live births among births with no use. Similarly, U5MR is 41 per 1000 live births as compared to 61 per 1000 live births among births with preceding use of contraceptive and no use respectively. The use of reversible modern contraceptives prior to birth is protective against child mortality even among births with preceding birth interval of less than 24 months.

Conclusions

This study provides evidence of dual benefit of contraceptive use. Such information is important for promoting evidence-based advocacy to expand use of family planning services. This will help the country to achieve Sustainable Development Goal 3.2 which calls for end of preventable deaths during childhood.

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First paper providing evidence of direct effect of modern contraceptive use on child mortality in India.

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Contraceptive use increases birth intervals, and births with large preceding birth intervals have higher chances of survival.

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Use of modern contraceptive prior to birth reduces risk of child mortality even in the absence of large birth intervals.

Phosphorous-Doped Graphitic Material as a Solid Acid Catalyst for Microwave-Assisted Synthesis of β-Ketoenamines and Baeyer-Villiger Oxidation

Synthesis of phosphorous-doped graphitic materials (P-Gc) using phytic acid as a precursor was done in a microwave oven in a cost- and time-effective green way. The material was used as a solid acid catalyst for microwave (MW)-assisted synthesis of β-ketoenamines and Baeyer-Villiger (BV) oxidation. In the case of BV oxidation, hydrogen peroxide (H2O2) was used as a green oxidant. For β-ketoenamines, in most cases, 100% conversion with an ∼95% yield was achieved in ethyl acetate medium. In solvent-free conditions, the yield of β-ketoenamines was ∼75%. A kinetic study suggested that the resonance stabilization of the positive reaction center happens in the transition state for β-ketoenamine synthesis. In BV oxidation, cyclic ketones were converted to their corresponding cyclic esters in good to high yields (∼80% yield) in a shorter reaction time (6-20 min). As per our knowledge, this is the first report of BV oxidation catalyzed by a heteroatom-doped graphitic material. For BV oxidation, the phosphoric acid functional groups present in P-Gc might increase the electrophilicity of the carbonyl group of the ketones to compensate for the weakness of H2O2 as a nucleophile and a spiro-bisperoxide intermediate has been identified in high-resolution mass spectrometry.

A Flexible Composite Mechanical Energy Harvester from a Ferroelectric Organoamino Phosphonium Salt

A new binary organic salt diphenyl diisopropylamino phosphonium hexaflurophosphate (DPDP⋅PF₆ ) was shown to exhibit a good ferroelectric response and employed for mechanical energy harvesting application. The phosphonium salt crystallizes in the monoclinic noncentrosymmetric space group Cc and exhibits an H-bonded 1D chain structure due to N-H⋅⋅⋅F interactions. Ferroelectric measurements on the single crystals of DPDP⋅PF₆ gave a well-saturated rectangular hysteresis loop with a remnant (P_r ) polarization value of 6 μC cm^-2 . Further, composite devices based on polydimethylsiloxane (PDMS) films for various weight percentages (3, 5, 7, 10 and 20 wt %) of DPDP⋅PF₆ were prepared and examined for power generation by using an impact test setup. A maximum output peak-to-peak voltage (V_PP ) of 8.5 V and an output peak-to-peak current (I_PP ) of 0.5 μA was obtained for the non-poled composite film with 10 wt % of DPDP⋅PF₆ . These results show the efficacy of organic ferroelectric substances as potential micropower generators.

Human rights approach to maternal & child health: has India fared well?

BACKGROUND & OBJECTIVES

The objectives of the study were to examine: right to access maternal health; right to access child health; and right to access improved water and sanitation in India.

METHODS

We used large-scale data sets like District Level Household Survey conducted in 2007-08 and National Family Health Surveys conducted during 1992-93, 1998-99, and 2005-06 to fulfil the objectives. The selection of the indicator variables was guided by the Human Rights' Framework for Health and Convention of the Rights of the Child- Articles 7, 24 and 27. We used univariate and bivariate analysis along with ratio of access among non-poor to access among poor to fulfil the objectives.

RESULTS

Evidence clearly suggested gross violation of human rights starting from the birth of an individual. Even after 60 years of independence, significant proportions of women and children do not have access to basic services like improved drinking water and sanitation.

INTERPRETATION & CONCLUSIONS

There were enormous socio-economic and residence related inequalities in maternal and child health indicators included in the study. These inequalities were mostly to the disadvantage of the poor. The fulfilment of the basic human rights of women and children is likely to pay dividends in many other domains related to overall population and health in India.

Consent and coercion: examining unwanted sex among married young women in India

CONTEXT

Although there is a growing body of research examining the issue of nonconsensual sex among adolescents, few studies have looked at coerced sex within marriage in settings where early marriage is common, or at sex that may not be perceived as forced, but that is unwanted.

METHODS

A cross-sectional study, using both survey research and in-depth interviews, was conducted among 1,664 married young women in Gujarat and West Bengal, India. Descriptive data and multinomial logistic regression were used to identify the prevalence and risk factors for occasional and frequent unwanted sex. Qualitative data were analyzed to examine the context in which unwanted sex takes place.

RESULTS

Twelve percent of married young women experienced unwanted sex frequently; 32% experienced it occasionally. The risk of experiencing unwanted sex was lower among women who knew their husband fairly well at the time of marriage, regularly received support from their husband in conflicts with other family members or lived in economically better-off households. Frequent unwanted sex was associated with not yet having had a child or having become pregnant, with lower education and with agreeing with norms that justify wife beating.

CONCLUSION

For married young women, sex is not always consensual or wanted. Further research is required to determine the effects of unwanted sex on sexual and reproductive health outcomes and to help programs develop the best strategies for dealing with coerced sex within marriage.

Can women's childbearing and contraceptive intentions predict contraceptive demand? Findings from a longitudinal study in Central India

CONTEXT

To predict the need for contraceptive services, family planning program managers often rely on levels of unmet need derived from measures of childbearing intentions. However, women's intention to use a method has not received as much attention as a measure of contraceptive demand.

METHODS

A survey was conducted in 1999 in rural Madhya Pradesh, India, among a subsample of women who had participated in the 1992-1993 National Family Health Survey (NFHS). The women's childbearing and contraceptive behaviors were compared with the intentions they had stated in the NFHS, and logistic regression was performed to analyze the association between socioeconomic and demographic variables and inconsistent behavior.

RESULTS

Among women who were fecund and married in 1992-1993, 29% of those who intended to have children and 61% of those who intended not to have children failed to adhere to their intentions by 1999. Furthermore, 51% of women who were not practicing contraception at the time of the NFHS but planned to do so acted against their intention by 1999, as did 29% of those who planned not to use a method. NFHS respondents who intended both not to have children and to use a method were more likely than others to have used a method by 1999 (63% vs. 25-41%). Age and history of child death were key factors associated with inconsistency between women's intentions and behavior.

CONCLUSIONS

In India, use of both contraceptive and childbearing intentions predicts contraceptive demand better than use of either indicator alone, and may thus help program planners estimate future demand for contraceptive services.

Inhaler devices for the treatment of asthma and chronic obstructive airways disease (COPD)

The research evidence on the effectiveness of inhaler devices for the treatment of asthma and chronic obstructive pulmonary disease published in a recent issue of Effective Health Care is reviewed.

Comparison of the effectiveness of inhaler devices in asthma and chronic obstructive airways disease: a systematic review of the literature

BACKGROUND

Asthma and chronic obstructive pulmonary disease (COPD) are common diseases of the airways and lungs that have a major impact on the health of the population. The mainstay of treatment is by inhalation of medication to the site of the disease process. This can be achieved by a number of different device types, which have wide variations in costs to the health service. A number of different inhalation devices are available. The pressurised metered-dose inhaler (pMDI) is the most commonly used and cheapest device, which may also be used in conjunction with a spacer device. Newer chlorofluorocarbons (CFC)-free inhaler devices using hydrofluoroalkanes (HFAs) have also been developed. The drug is dissolved or suspended in the propellant under pressure. When activated, a valve system releases a metered volume of drug and propellant. Other devices include breath-actuated pMDIs (BA-pMDI), such as Autohaler and Easi-Breathe. They incorporate a mechanism activated during inhalation that triggers the metered-dose inhaler. Dry powder inhalers (DPI), such as Turbohaler, Diskhaler, Accuhaler and Rotahaler, are activated by inspiration by the patient. The powdered drug is dispersed into particles by the inspiration. With nebulisers oxygen, compressed air, or ultrasonic power is used to break up solutions or suspensions of medication into droplets for inhalation. The aerosol is administered by mask or by a mouthpiece. There has been no previous systematic review of the evidence of clinical effectiveness and cost-effectiveness of these different inhaler devices.

OBJECTIVES

To review systematically the clinical effectiveness and cost-effectiveness of inhaler devices in asthma and COPD.

METHODS

The different aspects of inhaler devices were separated into the most clinically relevant comparisons. Methods involved systematic searching of electronic databases and bibliographies for randomised controlled trials (RCTs) and systematic reviews. Pharmaceutical companies and experts in the field were contacted for further information. Trials that met the inclusion criteria were appraised and data extraction was under-taken by one reviewer and checked by a second reviewer, with any discrepancies being resolved through agreement. RESULTS--IN VITRO CHARACTERISTICS VERSUS IN VIVO TESTING AND CLINICAL RESPONSE: There is evidence that when comparative testing is performed on inhaler devices using the same methods, there is some correlation between particle size measurements and clinical response. However, the measurements are dependent upon the methods used, and a single measure of a device in isolation is of limited value. Also, there is little data on comparing devices of different types. There is currently insufficient data to verify the ability of in vitro assessments to predict inhaler performance in vivo. RESULTS--EFFECTIVENESS OF METERED-DOSE INHALERS FOR THE DELIVERY OF CORTICOSTEROIDS IN ASTHMA: The review of three trials in children and 21 trials in adults demonstrated no evidence to suggest clinical benefits of any other inhaler device over a pMDI in corticosteroid delivery. RESULTS--EFFECTIVENESS OF METERED-DOSE INHALERS FOR THE DELIVERY OF BETA-AGONISTS IN STABLE ASTHMA: In children, 11 studies were reviewed, of which seven compared the Turbohaler with the pMDI. One study found a significant treatment difference in peak expiratory flow rate, although there were differences in the patients' baseline characteristics. In adults, a review of 70 studies found no demonstrable difference in the clinical bronchodilator effect of short-acting b2-agonists delivered by the standard pMDI compared with that produced by any other DPI, HFA-pMDI or the Autohaler device. The finding that HFA-pMDIs may reduce treatment failure and oral steroid requirement in beta-agonist delivery needs further confirmatory research in adequately randomised clinical trials. RESULTS--EFFECTIVENESS OF NEBULISERS VERSUS METERED-DOSE INHALERS FOR THE DELIVERY OF BRONCHODILATORS IN STABLE ASTHMA: In children, three included trials compared different devices with a nebuliser and demonstrated no evidence of clinical superiority of nebulisers over inhaler devices in bronchodilator delivery. A total of 23 studies in adults found no equivalence for the main pulmonary outcomes and no evidence of difference in other outcomes. RESULTS--EFFECTIVENESS OF METERED-DOSE INHALERS FOR THE DELIVERY OF BETA-AGONISTS IN COPD: Only two studies were included in this review. No evidence of clinical difference was found in beta-agonist delivery. RESULTS--EFFECTIVENESS OF NEBULISERS VERSUS METERED-DOSE INHALERS FOR THE DELIVERY OF BRONCHODILATORS IN COPD: Evidence from 14 trials demonstrated equivalence for the main outcomes of pulmonary function. For other outcomes there was no evidence of treatment difference in bronchodilator delivery. RESULTS--PATIENTS' ABILITY TO USE METERED-DOSE INHALERS: Differences among studies and the heterogeneity of the results make it difficult to draw conclusions about inhaler technique differences between device types. The review of technique after teaching the correct technique suggests that there is no difference in patients' ability to use DPI or pMDIs. RESULTS--ECONOMIC ANALYSIS: The total number of NHS prescriptions for inhaler therapy for asthma in 1998 was over 31 million, with a net ingredient cost in excess of 392 million GB pounds. This economic assessment uses decision analysis to estimate the relative cost-effectiveness of inhaler devices for the delivery of bronchodilator and corticosteroid inhaled therapy. Overall, there were no differences in patient outcomes among the devices. On the assumption that the devices were clinically equivalent, pMDIs were the most cost-effective devices for asthma treatment.

CONCLUSIONS

This systematic review examined the evidence from clinical trials evaluating the clinical effectiveness of different inhaler devices in the delivery of inhaled corticosteroids and beta2-bronchodilators for patients with asthma and COPD. The evidence from the published clinical literature demonstrates no difference in clinical effectiveness between nebulisers and alternative inhaler devices compared to standard pMDI with or without a spacer device. The cost-effectiveness evidence therefore favours pMDIs (or the cheapest inhaler device) as first-line treatment in all patients with stable asthma unless other specific reasons are identified. Patients can use pMDIs as effectively as other inhaler devices as long as the correct inhalation technique is taught. CONCLUSIONS--RECOMMENDATIONS FOR RESEARCH: Further clinical trials are required to demonstrate any differences in the clinical effectiveness and cost-effectiveness of inhaler devices and nebulisers compared with pMDIs. These should be of sufficient statistical power and methodological rigour to demonstrate any clinical benefit. Trials should be undertaken in community settings to ensure the generalisability of results. Outcome measures should be more patient-centred and report adverse effects more completely. Reporting of data from trials should be improved.

A modified procedure for calculating person years of life lost

"This study has proposed a modified procedure for the calculation of PYLL [person years of life lost] which takes competing risk of death into consideration. An application of the modified and old procedures to the data on ten leading causes of death in Bombay shows that the old procedure underestimates the actual PYLL in...all the causes of death under study except dysentery, pneumonia and prematurity. This study suggests tuberculosis, pneumonia, prematurity, heart disease and dysentery in males and pneumonia, prematurity, dysentery, tuberculosis and heart disease in females in that order, as the first five leading causes of death in Bombay in 1984."