Magnetic exchange interactions and non-Debye relaxation in spin-3/2 frustrated Kagomé magnet Co3V2O8

We report the experimental determination of the magnetic exchange parameter (J/kB= 2.88 ± 0.02 K) for the Spin-3/2 ferromagnetic (FM) Kagomé lattice system: Co3V2O8using the temperature dependence of dc-magnetic susceptibilityχ(T) data by employing the fundamental Heisenberg linear chain model. Our results are quite consistent with the theoretically reported nearest neighbor dominant FM exchange coupling strengthJex-NN∼2.45 K. Five different magnetic phase transitions (6.2-11.2 K) and spin-flip transitions (9.6-7.7 kOe) have been probed using the∂(χT)/∂Tvs.T, heat capacity (CP-T) and differential isothermal magnetization curves. Among such sequence of transitions, the prominent ones being incommensurate antiferromagnetic (AFM) state at 11.2 K, commensurate AFM state at 8.8 K, and commensurate FM state across 6.2 K. All the successive magnetic phase transitions have been mapped onto a single H-T plane through which one can easily distinguish the above-mentioned different phases. The magnetic contribution of theCP-TnearTN(11.2 K) has been analyzed using the power-law expressionCM=A|T-TN|-αresulting in the critical exponentα= 0.18 ± 0.01 (0.15 ± 0.003) forTTN), respectively for the Co3V2O8. It is interesting to note that non-Debye type dipole relaxation is quite prominent in Co3V2O8and was evident from the Kohlrausch-Williams-Watts analysis of complex modulus and impedance spectra (0⩽β⩽1). Mott's variable-range hopping of charge carriers process is evident through the resistivity analysis (ρac-T-1/4) in the temperature range 275 ∘C-350 ∘C. Moreover, the frequency-dependent analysis ofσac(ω) follows Jonscher's power law yielding two distinct activation energies (Ea∼0.37 and 2.29 eV) between the temperature range 39 ∘C-99 ∘C and 240 ∘C-321 ∘C.

Spin glass states in multicomponent layered perovskites

Temperature-dependent dc-magnetization and ac-susceptibility curves have been recorded for series of single and double layered Ruddlesden-Popper multicomponent perovskites with chemical formula A2BO4 and A3B2O7, respectively, with (La, Sr) on A-sites and up to 7 different cations on the B-sites (Ti, Cr, Mn, Fe, Co, Ni, Cu). The phase purity and chemical homogeneity of the compounds were investigated by X-ray diffraction and energy dispersive X-ray spectroscopy. Independently of the composition, spin glassiness is observed in both systems. Scaling analyses suggest the materials undergo spin glass phase transitions at low temperatures. Yet, qualitative differences are observed between the single-layered and double-layered systems, which are discussed in the light of the spatial dimensionality and magnetic interaction in layered oxide perovskites.

Reentrant canonical spin-glass dynamics and tunable field-induced transitions in (GeMn)Co2O4Kagomé lattice

We report on the reentrant canonical semi spin-glass characteristics and controllable field-induced transitions in distorted Kagomé symmetry of (GeMn)Co2O4. ThisB-site spinel exhibits complicated, yet interesting magnetic behaviour in which the longitudinal ferrimagnetic (FiM) order sets in below the Néel temperatureTFN∼ 77 K due to uneven moments of divalent Co (↑ 5.33μB) and tetravalent Mn (↓ 3.87μB) which coexists with transverse spin-glass state below 72.85 K. Such complicated magnetic behaviour is suggested to result from the competing anisotropic superexchange interactions (JAB/kB∼ 4.3 K,JAA/kB∼ -6.2 K andJBB/kB∼ -3.3 K) between the cations, which is extracted following the Néel's expression for the two-sublattice model of FiM. Dynamical susceptibility (χac(f, T)) and relaxation of thermoremanent magnetization,MTRM(t) data have been analysed by means of the empirical scaling-laws such as Vogel-Fulcher law and Power law of critical slowing down. Both of which reveal the reentrant spin-glass like character which evolves through a number of intermediate metastable states. The magnitude of Mydosh parameter (Ω ∼ 0.002), critical exponentzυ= (6.7 ± 0.07), spin relaxation timeτ0= (2.33 ± 0.1) × 10-18s, activation energyEa/kB= (69.8 ± 0.95) K and interparticle interaction strength (T0= 71.6 K) provide the experimental evidences for canonical spin-glass state below the spin freezing temperatureTF= 72.85 K. The field dependence ofTFobtained fromχac(T) follows the irreversibility in terms of de Almeida-Thouless mean-field instability in which the magnitude of crossover scaling exponent Φ turns out to be ∼2.9 for the (Ge0.8Mn0.2)Co2O4. Isothermal magnetization plots reveal two field-induced transitions across 9.52 kOe (HSF1) and 45.6 kOe (HSF2) associated with the FiM domains and spin-flip transition, respectively. Analysis of the inverse paramagnetic susceptibilityχp-1χp=χ-χ0after subtracting the temperature independent diamagnetic termχ0(=-3 × 10-3emu mol-1Oe-1) results in the effective magnetic momentμeff= 7.654μB/f.u. This agrees well with the theoretically obtainedμeff= 7.58μB/f.u. resulting the cation distributionMn0.24+↓A[Co22+↑]BO4in support of the Hund's ground state spin configurationS=3/2andS= 1/2of Mn4+and Co2+, respectively. TheH-Tphase diagram has been established by analysing all the parameters (TF(H),TFN(H),HSF1(T) andHSF2(T)) extracted from various magnetization measurements. This diagram enables clear differentiation among the different phases of the (GeMn)Co2O4and also illustrates the demarcation between short-range and long-range ordered regions.

Using scenario‐based assessments to examine the feasibility of integrating preventive nutrition services through the primary health care system in Bangladesh

The National Nutrition Services of Bangladesh aims to deliver nutrition services through the primary health care system. Little is known about the feasibility of reshaping service delivery to close gaps in nutrition intervention coverage and utilization. We used a scenario‐based feasibility testing approach to assess potential implementation improvements to strengthen service delivery. We conducted in‐depth interviews with 31 service providers and 12 policymakers, and 5 focus group discussions with potential beneficiaries. We asked about the feasibility of four hypothetical scenarios for preventive and promotive nutrition service delivery: community‐based events (CBE) for pregnant women, well‐child services integrated into immunization contacts; CBE for well‐children, and well‐child visits at facilities. Opinions on service delivery platforms were mixed; some recommended new platforms, but others suggested strengthening existing delivery points. CBE for pregnant women was perceived as feasible, but workforce shortages emerged as a key barrier. Challenges such as equipment portability, upset children and a fast‐moving service environment suggested low feasibility of integrating nutrition into outreach immunization contacts. In contrast, CBE and facility‐based well‐child visits emerged as feasible options, conditional on having the necessary workforce, structural readiness and budget support. On the demand side, enabling factors include using interpersonal communication and involving community leaders to increase awareness, organizing events at a convenient time and place for both providers and beneficiaries, and incentives for beneficiaries to encourage participation. In conclusion, integrating preventive and promotive nutrition services require addressing current challenges in the health system, including human resource and logistic gaps, and investing in creating demand for preventive services.

This study uses a scenario‐based feasibility testing approach to explore potential interventions to strengthen preventive and promotive nutrition service delivery through the primary health care system.

Our findings highlight three highly feasible potential platforms (community‐based events [CBE] for pregnant women, CBE for well‐children and well‐child visits at facilities) to expand preventive services. Scaling these community‐based services requires addressing current challenges in the health system (including human resource and logistic gaps) and investment in demand creation for these services.

Adolescent birth and child undernutrition: an analysis of demographic and health surveys in Bangladesh, 1996-2017

Adolescent birth is a major global concern owing to its adverse effects on maternal and child health. We assessed trends in adolescent birth and examined its associations with child undernutrition in Bangladesh using data from seven rounds of Demographic and Health Surveys (1996–2017, n = 12,006 primiparous women with living children <5 years old). Adolescent birth (10–19 years old) declined slowly, from 84% in 1996 to 71% in 2017. Compared with adult mothers (≥20 years old), young adolescent mothers (10–15 years old) were more likely to be underweight (+11 pp), have lower education (−24 pp), have less decision‐making power (−10 pp), live in poorer households (−0.9 SD) with poorer sanitation (−15 pp), and have poorer feeding practices (10 pp), and were less likely to access health and nutrition services (−3 to −24 pp). In multivariable regressions controlled for known determinants of child undernutrition, children born to adolescents had lower height‐for‐age Z‐scores (−0.29 SD for young and −0.10 SD for old adolescents (16–19 years old)), weight‐for‐age Z‐score (−0.18 and −0.06 SD, respectively) as well as higher stunting (5.9 pp) and underweight (6.0 pp) than those born to adults. In conclusion, birth during adolescence, a common occurrence in Bangladesh, is associated with child undernutrition. Policies and programs to address poverty and improve women's education can help delay marriage, reduce early childbearing, and improve child growth.

Early marriage and early childbearing in South Asia: trends, inequalities, and drivers from 2005 to 2018

Early marriage (EM) and early childbearing (ECB) have far-reaching consequences. This study describes the prevalence, trends, inequalities, and drivers of EM and ECB in South Asia using eight rounds of Demographic and Health Survey data across 13 years. We report the percentage of ever-married women aged 20-24 years (n = 105,150) married before 18 years (EM) and with a live birth before 20 years (ECB). Relative trends were examined using average annual rate of reduction (AARR). Inequalities were examined by geography, marital household wealth, residence, and education. Sociodemographic drivers of changes for EM were assessed using regression decomposition analyses. We find that EM/ECB are still common in Bangladesh (69%/69%), Nepal (52%/51%), India (41%/39%), and Pakistan (37%/38%), with large subnational variation in most countries. EM has declined fastest in India (AARR of -3.8%/year), Pakistan (-2.8%/year), and Bangladesh (-1.5%/year), but EM elimination by 2030 will not occur at these rates. Equity analyses show that poor, uneducated women in rural areas are disproportionately burdened. Regression decomposition analysis shows that improvements in wealth and education explained 44% (India) to 96% (Nepal) of the actual EM reduction. Investments across multiple sectors are required to understand and address EM and ECB, which are pervasive social determinants of maternal and child wellbeing.

Effective coverage of nutrition interventions across the continuum of care in Bangladesh: insights from nationwide cross-sectional household and health facility surveys

INTRODUCTION

Improving the impact of nutrition interventions requires adequate measurement of both reach and quality of interventions, but limited evidence exists on advancing coverage measurement. We adjusted contact-based coverage estimates, taking into consideration the inputs required to deliver quality nutrition services, to calculate input-adjusted coverage of nutrition interventions across the continuum of care from pregnancy through early childhood in Bangladesh.

METHODS

We used data from the 2014 Bangladesh Demographic and Health Surveys to assess use of maternal and child health services and the 2014 Service Provision Assessment to determine facility readiness to deliver nutrition interventions. Service readiness captured availability of nutrition-specific inputs (including human resources and training, equipment, diagnostics and medicines). Contact coverage was combined with service readiness to create a measure of input-adjusted coverage at the national and regional levels, across place of residence, and by maternal education and household socioeconomic quintiles.

RESULTS

Contact coverage varied from 28% for attending at least four ANC visits to 38% for institutional delivery, 35% for child growth monitoring and 81% for sick child care. Facilities demonstrated incomplete readiness for nutrition interventions, ranging from 48% to 51% across services. Nutrition input-adjusted coverage was suboptimal (18% for ANC, 23% for institutional delivery, 20% for child growth monitoring and 52% for sick child care) and varied between regions within the country. Inequalities in input-adjusted coverage were large during ANC and institutional delivery (14-17 percentage points (pp) between urban and rural areas, 15 pp between low and high education, and 28-34 pp between highest and lowest wealth quintiles) and less variable for sick child care (<2 pp).

CONCLUSION

Nutrition input-adjusted coverage was suboptimal and varied subnationally and across the continuum of care in Bangladesh. Special efforts are needed to improve the reach as well as the quality of health and nutrition services to achieve the Sustainable Development Goals.

Neutron diffraction evidence for local spin canting, weak Jahn-Teller distortion, and magnetic compensation in Ti1-x Mn x Co2O4 spinel

A systematic study using neutron diffraction and magnetic susceptibility is reported on Mn substituted ferrimagnetic inverse spinel Ti_1-x Mn _x Co₂O₄ in the temperature interval 1.6 K [Formula: see text] T [Formula: see text] 300 K. Our neutron diffraction study reveals cooperative distortions of the TO₆ octahedra in the Ti_1-x Mn _x Co₂O₄ system for all the Jahn-Teller active ions T  =  Mn³⁺ , Ti³⁺ and Co³⁺ , having the electronic configurations 3d ¹, 3d ⁴ and 3d ⁶, respectively which are confirmed by the x-ray photoelectron spectroscopy. Two specific compositions (x  =  0.2 and 0.4) have been chosen in this study because these two systems show unique features such as; (i) noncollinear Yafet-Kittel type magnetic ordering, and (ii) weak tetragonal distortion with c/a  <  1, in which the apical bond length d _c (T _B -O) is longer than the equatorial bond length d _ab (T _B -O) due to the splitting of the e _g level of Mn³⁺ ions into [Formula: see text] and [Formula: see text]. For the composition x  =  0.4, the distortion in the T _B O₆ octahedra is stronger as compared to x  =  0.2 because of the higher content of trivalent Mn. Ferrimagnetic ordering in Ti_0.6Mn_0.4Co₂O₄ and Ti_0.8Mn_0.2Co₂O₄ sets in at 110.3 and 78.2 K, respectively due to the presence of unequal magnetic moments of cations, where Ti³⁺ , Mn³⁺ , and Co³⁺ occupy the octahedral, whereas, Co²⁺ sits in the tetrahedral site. For both compounds an additional weak antiferromagnetic component could be observed lying perpendicular to the ferrimagnetic component. The analysis of static and dynamic magnetic susceptibilities combined with the heat-capacity data reveals a magnetic compensation phenomenon (MCP) at T _COMP  =  25.4 K in Ti_0.8Mn_0.2Co₂O₄ and a reentrant spin-glass behaviour in Ti_0.6Mn_0.4Co₂O₄ with a freezing temperature of  ∼110.1 K. The MCP in this compound is characterized by sign reversal of magnetization and bipolar exchange bias effect below T _COMP with its magnitude depending on the direction of external magnetic field and the cooling protocol.

Quality-Adjusted Coverage of Nutrition Interventions Across the Continuum of Care: Insights from Household and Health Facility Data in Bangladesh

Objectives

Improving the impact of nutrition interventions requires adequate measurement of both reach and quality of interventions, but limited evidence exists on advancing coverage measurement. We adjust crude health coverage estimates, taking into consideration the inputs required to deliver quality nutrition services, across the continuum of care in Bangladesh.

Methods

We used data from Bangladesh Demographic and Health Surveys 2014 to assess use of maternal and child health services and Service Provision Assessments 2014 to determine facility readiness to deliver nutrition interventions during antenatal (ANC), institutional delivery, and postnatal care (PNC). Service readiness was computed as the mean availability of four nutrition-specific inputs, capturing human resources and training, equipment, diagnostics, and medicines. Crude coverage was combined with service readiness to create a measure of input-adjusted nutrition coverage at the national and regional levels, across place of residence, and by maternal educational and household socio-economic quintiles.

Results

Crude coverage varied, with greater use of any ANC (79%) and postnatal care (61–81%), than institutional delivery (37%). Nutrition service readiness was lower than crude coverage at each time point, such that nutrition input-adjusted coverage was 45% for ANC, 25% for institutional delivery, and 38–49% for preventive and sick child postnatal care, respectively. Input-adjusted coverage varied by 10–22 percentage points (pp) between regions within the country. Inequalities in input-adjusted coverage were large during ANC and institutional delivery (12–17 pp between urban and rural areas, ∼17pp between low and high education, and 30–36pp between highest and lowest wealth quintiles), and less variable for postnatal care (&lt;10%).

Conclusions

Nutrition input-adjusted coverage was suboptimal and varied sub-nationally and across the continuum of care in Bangladesh. Special efforts are needed to improve the reach as well as the quality of health and nutrition services to achieve the Sustainable Development Goals.

Funding Sources

Bill & Melinda Gates Foundation through A4NH.

How Has Early Marriage, a Critical Social Determinant of Child Stunting and Wasting, Changed over a Decade in South Asia? Trends, Inequities and Drivers, 2005 to 2018

Objectives

In South Asia, many women are married before their 18th birthday and give birth soon after. Delaying marriage is an attractive nutrition policy target as previous research shows that early marriage (EM) is associated with poor child growth outcomes, operating through many pathways. We sought to describe the prevalence, trends, inequities and predictors of EM in South Asia.

Methods

We used Demographic and Health Survey data available in the last 15 years for 7 South Asian countries: Afghanistan (AF; 2015), Bangladesh (BG; 2007, 2014), India (IN; 2006, 2016), Maldives (MV; 2009, 2017), Nepal (NP; 2005, 2016), and Pakistan (PK; 2007, 2018). EM was defined as the percentage of women aged 20–24 years who were married before 18 years of age. Our analyses included 133,680 women. The prevalence and absolute burden in terms of number of individuals affected were estimated for each survey round. Relative trends were examined using average annual rate of reduction (AARR). Inequities were examined by geography, wealth, place of residence, and education. Regression decomposition was used to examine the contribution of improvements in wealth and education to EM reductions.

Results

The most recent rounds of data show that EM is common in BG (69%), AF (52%), NP (52%), IN (41%), and PK (37%) but not MV (4%). IN accounts for 68% of the regional burden, with 21.9 million women married early in 2016. The fastest reductions in EM have occurred in IN (59% to 41% over 10 years, an AARR of −3.8% per year), PK (−2.8% per year), and BG (−1.5% per year). EM prevalence varies subnationally, e.g., from 5% to 52% for states within IN in 2016. Equity analysis shows that EM disproportionately burdens women who are poor, uneducated, and live in rural areas. Progress in narrowing these inequalities has been slow in the past decade. When examining predictors of EM, completion of secondary school was associated with a 20% (PK) to 36% (NP) lower EM prevalence. Decomposition analysis shows that improvements in wealth and education alone predicted between 46% (PK) and 96% (NP) of the actual EM reduction.

Conclusions

EM remains highly prevalent in South Asia and trends indicate an enduring problem. The nutrition community should invest in building linkages with researchers and practitioners to further understand and address this important social determinant of poor child growth.

Funding Sources

A4NH/IFPRI.

Using Novel Scenario-Based Assessments to Examine Feasibility of Integrating Preventive Nutrition Services Through the Primary Healthcare System in Bangladesh

Objectives

Bangladesh's National Nutrition Services aims to deliver nutrition services to pregnant women and children through the primary health care system. Previous research highlighted gaps in coverage of preventive nutrition intervention delivery through this system but little is known about feasibility of reshaping service delivery to close the gaps. Prior to designing new approaches, we used a novel scenario-based feasibility testing approach to assess potential to strengthen service delivery.

Methods

We interviewed 32 service providers and 16 policymakers and conducted 4 focus group discussions with potential beneficiaries, asking respondents about the feasibility of four hypothetical scenarios for preventive service delivery: community-based events (CBE) for pregnant women; well-child services integrated into immunization contacts; CBE for well-children and well-child visits at facilities. Transcribed interviews were systematically coded, synthesized and interpreted using a pre-defined framework.

Results

Opinions on the need for new platforms for preventive services were mixed; some recommended new platforms, but others suggested strengthening existing delivery points. CBE for pregnant women were perceived as feasible, but workforce shortages emerged as a key challenge. Challenges such as equipment portability, upset children, and a fast-moving service environment suggested low feasibility of integrating nutrition into immunization contacts. In contrast, CBE and facility-based well-child visits emerged as feasible options, conditional on having the necessary workforce, structural readiness and budget support. On the demand side, enabling factors include using interpersonal communication and involving community leaders to increase awareness, organizing events at a convenient time and place for both providers and beneficiaries, and incentives for beneficiaries to encourage participation.

Conclusions

A scenario-based approach is an efficient method to assess potential feasibility options for nutrition service delivery. Introducing preventive nutrition services requires addressing current challenges in the health system, including human resource and logistic gaps, and investing in creating demand for preventive services.

Funding Sources

Bill & Melinda Gates Foundation, through A&T, managed by FHI 360.

Why Are Adolescent Mothers More iikely to Have Stunted and Underweight Children Than Adult Mothers? A Path Analysis Using Data from 30,000 Bangladeshi Mothers, 1996–2014

Objectives

Adolescent pregnancy is a major global concern due to its adverse effects on maternal and child health and wellbeing. Bangladesh has one of the highest rates of adolescent pregnancy globally. We sought to examine trends in adolescent pregnancy and associated factors in Bangladesh in the last two decades, and to understand why children of adolescent mothers are at high risk of poor growth.

Methods

Data were from 6 rounds of Bangladesh Demographic and Health Survey (1996–2014). Women aged 15–49 years who gave birth in the 5 years preceding each survey (n = 30,331) were classified based on age at first birth: ≤19 years (adolescence), 20–24 years (young adulthood), and ≥25 years (adulthood). Trend analysis was used to assess the progress over time. Multivariable regression and structural equation models were used to understand how adolescent pregnancy is linked to child undernutrition through maternal nutritional status, education and bargaining power, health service use, child feeding and living conditions.

Results

Adolescent pregnancy has declined slowly, from 84% in 1996 to 73% in 2014. Children born to adolescent mothers had lower z-scores for height-for-age (mean difference: −0·64 SD), weight-for-age (−0·45 SD), and higher prevalence of stunting (18 percentage points [pp]) and underweight (12pp) than children born to adult mothers. Compared to adult mothers, adolescent mothers were shorter (−0·8 cm), lighter (−6.9 kg), more likely to be underweight (+14pp), had lower education (−4·3 years), less decision-making power (−9pp), and lived in poorer households (−0·79 SD) with poorer sanitation (−23pp) (all P &lt; 0.05). Adolescent mothers were less likely to access ANC (−20pp), institutional delivery (−42pp), postnatal care services (−24pp) and had poorer complementary feeding practices (−15pp). In path analyses, these intermediate factors explained 66% of the association between adolescent pregnancy and child anthropometry, with the strongest links being through women's weight, education, socioeconomic status and complementary feeding practices.

Conclusions

Adolescent pregnancy is still the norm in Bangladesh. Policies and programs to address poverty and improve women's education can help to improve women's health, reduce early childbearing and break the intergenerational cycle of poverty and undernutrition.

Funding Sources

A4NH at IFPRI.

Can Multiple Forms of Undernutrition Among Children and Women Be Tackled Efficiently? A Case of Shared Determinants (P11-124-19)

Objectives

Globally, it is recognized that multiple forms of undernutrition exist. Yet, little evidence exists on co-existence of multiple forms of undernutrition or on the potential shared determinants of these manifestations. Therefore, using data from India, we aimed to: 1) estimate the co-occurrence of undernutrition among children (stunting and anemia) and women (underweight and anemia); and 2) identify their shared determinants.

Methods

We used National Family Health Survey data from 2016 (n = 126,338 children 6–59 mo; 159,752 women). We examined co-occurrence of stunting and anemia among children and underweight and anemia among women, comparing observed versus expected frequencies using chi-square tests. We used multivariate logistic regression models to study associations between nutrition outcomes and determinants (household, maternal and child-level), and identified determinants that were shared across the outcomes.

Results

The observed co-occurrence of stunting and anemia among children was 25% and of underweight and anemia among women was 15%. Observed frequencies were significantly greater than expected frequencies for all comparisons (P < 0.0001). Women's education (OR: 0.60 to 0.84), wealth status (OR: 0.56 to 0.81) and improved sanitation (OR: 0.74 to 0.94) were protective against all forms of undernutrition. Care during pregnancy was protective against stunting (OR = 0.83; P < 0.001) and anemia (OR = 0.94; P < 0.001) among children and underweight (OR = 0.88; P < 0.001) among women. Maternal underweight (OR = 1.31; P < 0.001) and anemia (OR = 1.09; P < 0.001) were risk factors for child undernutrition.

Conclusions

Co-occurrence of undernutrition is prevalent among women and children in India. Multiple forms of undernutrition also share similar determinants. Investing in reducing poverty, improving education, sanitation, and use of antenatal care could address multiple forms of undernutrition, thus ensuring more efficient use of resources.

Funding Sources

Bill & Melinda Gates Foundation through POSHAN, led by International Food Policy Research Institute.

Effect of elevated carbon dioxide on soil hydrothermal regimes and growth of maize crop (Zea mays L.) in semi-arid tropics of Indo-Gangetic Plains

To see the effect of climate change on the variation of soil hydrothermal regimes and growth of maize crop, an experiment was conducted in free-air carbon dioxide enrichment (FACE) facility during the kharif season of 2015 at Climate Change Facility of Indian Agricultural Research Institute, New Delhi, India. Under elevated CO₂ and ambient condition, surface bulk density (BD) were 1.38 Mgm^-3 and 1.44 Mgm^-3, respectively but BD were not significantly different. During different days after sowing (DAS), in 0 to 10-cm soil depth, soil water content (SWC) in FACE varied between 14.58-20.70%, whereas in ambient condition, SWC variations were in between 19.33-22.94%. In 10 to 20-cm soil depth, SWC ranged in between 20.47-27.14% in FACE and 23.57-25.42% in ambient condition for different DAS. It is also observed that the arrival of peak surface ST was 1 h early in elevated CO₂ condition. Photosynthetic rate increased by 5.7% on 44 DAS and 18.1% on 70 DAS under elevated carbon dioxide condition. Elevated carbon dioxide had reduced the stomatal conductance but the reduction was not significant. Like variation in air temperature for climate change, more intensive study is required to see the effect of climate change on soil temperature and its effect on crop growth.

Mn and As doping of β-FeSi2via a chemical method

β-FeSi₂ has been doped with Mn and As by chemical reduction which results in uniform doping and hence cost-effectiveness.

Effect of limited nickel availability on methane emission from EDTA treated soils: coenzyme M an alternative biomarker for methanogens

Methanogens utilize simple carbon compounds to produce methane (CH(4)) under strictly anaerobic condition. During methanogenesis, methyl coenzyme M (MeCoM) is reduced by MeCoM reductase enzyme to CH(4) involving a nickel-containing cofactor F(430). In this experiment, strong chelating agent like ethylenediaminetetraacetic acid (EDTA) was applied in soil to study its feasibility for suppressing methanogen activity and CH(4) production in soil. Application of EDTA significantly (P≤0.05) reduced CH(4) production in soil. Application of 60 ppm EDTA (soil weight basis) was the most effective among all treatments. Applied EDTA forms complex compounds with heavy metals like nickel (Ni) and increases Ni concentration in soil solution. Since methanogenesis is intracellular process, it is necessary for methanogens to assimilate those Ni-EDTA complexes inside cell to utilize Ni in EDTA treated soils. Results indicated that methanogens cannot utilize Ni in the presence of EDTA and that significantly (P≤0.05) reduced mcrA gene (coding MeCoM reductase enzyme) copy number and Co-M concentration in soil. Due to high correlation (r=0.901(*)) between Co-M concentration and mcrA gene copy numbers, Co-M concentration could be used as an alternative biomarker for methanogens. Therefore, it could be propose that 60 ppm EDTA could be an optimum dose to suppress CH(4) emission from soil by restricting Ni availability to methanogens.

Surface-modified cobalt oxide nanoparticles: new opportunities for anti-cancer drug development

The development of smart nanoparticles that can exhibit the anti-cancer activity, introduces better efficacy and lower toxicity for treatment. The present study was aimed to evaluate the anti-cancer activity of surface functionalized CoO nanoparticles against Jurkat (T-cell lymphoma) and KB (oral carcinoma) cell lines. The nano-sized cobalt oxide nanoparticles (CoO) was prepared by thermal decomposition method followed by surface modification using phosphonomethyl iminodiacetic acid (PMIDA). The PMIDA-coated CoO nanoparticle was characterized by X-ray diffraction, dynamic light scattering, and transmission electron microscopy; and the conjugation was analyzed by Fourier transform infrared spectroscopy. The resultant nanoparticles with an average size less than 100 nm measured by dynamic light scattering and transmission electron microscopy. Cytotoxicity study, flow cytometric analysis and scanning electron micrographs have been revealed that PMIDA-coated nanoparticles significantly enhances the cellular uptake of the nanoparticle and thus facilitates apoptosis of cancer cell (Jurkat and KB). For the application of PMIDA-coated CoO nanoparticles in the medical field, doxorubicin, a potent anti-cancer drug, has been used in similar fashion in this experimental design and all these effects or patterns were observed.

Changes in enzymatic activities and microbial properties in vermicompost of water hyacinth as affected by pre-composting and fungal inoculation: a comparative study of ergosterol and chitin for estimating fungal biomass

In this experiment, three different fungal species, viz. Trichoderma viridae, Aspergillus niger and Phanerochaete chrysosporium, were inoculated in 7 day and 15 day partially decomposed water hyacinth to study their effect on enzymatic activities, microbial respiration and fungal biomass of the final stabilized product. The results suggested that increasing the duration of pre-composting from 7 days to 15 days did not show any significant effect on the activities of hydrolytic enzymes. Inoculation of fungi significantly (P < or = 0.05) increased cellulase, protease and acid and alkaline phosphatase activities. The highest value of ergosterol was recorded in A. niger-inoculated vermicomposts. Inoculation of P. chrysosporium in initial organic waste registered the highest chitin content in vermicompost. A comparison of fungal biomass and chitin content revealed a conversion factor of 2.628 with a standard deviation of 0.318. Due to significant correlation (r = 0.864), this conversion factor allows for the calculation of fungal biomass from chitin, which is comparatively more stable than ergosterol.

Changes in microbial properties and nutrient dynamics in bagasse and coir during vermicomposting: quantification of fungal biomass through ergosterol estimation in vermicompost

In this experiment, different microorganisms viz., Trichoderma viridae, Aspergillus niger and Bacillus megaterium were inoculated in bagasse and coir with the objective to study their effect on nutrient dynamics and microbial properties, specially effect on fungal status in these waste materials. Fungal biomass (FBC) was calculated from the ergosterol content in the vermicompost samples. Inoculation of B. megaterium registered comparatively higher TP content in the final stabilized product. Vermicomposting increased microbial biomass carbon (MBC) and nitrogen (MBN) content in bagasse and coir. Microbial biomass carbon to nitrogen ratio (MBC/ MBN) was comparatively narrower in fungi inoculated vermicomposts and FBC/MBC ratio was increased up to 11.69 from 9.51 of control during vermicomposting.

Effect of microbial inoculation during vermicomposting of different organic substrates on microbial status and quantification and documentation of acid phosphatase

In this experiment, three microbial strains were inoculated in two different organic wastes to study their effect on the humic acids content, acid phosphatase activity and microbial properties of the final stabilized products. Pyrophosphate extract of vermicomposts were analyzed through polyacrylamide gel electrophoresis to study the nature of a isozymes in different treatments. Results suggested that vermicomposting increased humic acids content and acid phosphatase activity in organic substrates and microbial inoculation further enhanced the rate of humification and enzyme activity. Although humic acids content in different microorganism-inoculated vermicomposts were statistically at par, acid phosphatase activity in these treatments was significantly (P<0.05) different. Results revealed that microbial respiration was increased due to vermicomposting, but a reduction in microbial biomass was recorded after stabilization of organic wastes. Although vermicomposting increased the value of microbial quotient (qCO(2)), microbial inoculation did not show any significant effect on qCO(2). The zymogram revealed that two isozymes of acid phosphatase (group II and group III) were present in all vermicompost samples and higher acid phosphatase activity in fungi-inoculated vermicomposts might be due to the presence of an additional isozyme (group I) of acid phosphatase.

Bio-functionalization of magnetite nanoparticles using an aminophosphonic acid coupling agent: new, ultradispersed, iron-oxide folate nanoconjugates for cancer-specific targeting

The present study describes a systematic approach towards the design and development of novel, bio-functionalized, magneto-fluorescent nanoparticles for cancer-specific targeting. Biocompatible, hydrophilic, magneto-fluorescent nanoparticles with surface-pendant amine, carboxyl or aldehyde groups, to be later used for bio-conjugation, were designed using an aminophosphonic acid coupling agent. These magneto-fluorescent nanoparticles were further functionalized with folic acid, using diverse conjugation strategies. A series of new iron-oxide folate nanoconjugates with excellent aqueous dispersion stability and reasonably good hydrodynamic sizes under a wide range of physiological conditions were developed. These ultradispersed nanosystems were analyzed for their physicochemical properties and cancer-cell targeting ability, facilitated by surface modification with folic acid. The nanoparticle size, charge, surface chemistry, magnetic properties and colloidal stability were extensively studied using a variety of complementary techniques. Confocal microscopy, performed with folate receptor positive human cervical HeLa cancer cells, established that these non-cytotoxic iron-oxide folate nanoconjugates were effectively internalized by the target cells through receptor-mediated endocytosis. Cell-uptake behaviors of nanoparticles, studied using magnetically activated cell sorting (MACS), clearly demonstrated that cells over-expressing the human folate receptor internalized a higher level of these nanoparticle-folate conjugates than negative control cells.

Changes in organic - C, N, P and K and enzyme activities in vermicompost of biodegradable organic wastes under liming and microbial inoculants

The aim of this work was to study the effect of different organic wastes, viz. cow dung, grass, aquatic weeds and municipal solid waste with lime and microbial inoculants on chemical and biochemical properties of vermicompost. Cow dung was the best substrate for vermicomposting. Application of lime (5 g/kg) and inoculation of microorganisms increased the nutrient content in vermicompost and also phosphatases and urease activities. Bacillus polymyxa, the free-living N-fixer, increased N-content of vermicompost significantly (p < or = 0.01) as compared to other inoculants.

A mathematical model on the effect of M. denticulata weed on different winter crops

Many weeds interfere with the productivity of wheat and other winter annual crops; however, one common weed Medicago denticulata, appears to have a beneficial effect. An experiment was conducted at Agricultural Experimental Farm of the Indian Statistical Institute, Giridih, Jharkhand to observe the effect of M. denticulata (a legume) on different crops yield of barley (Hordeum vulgare Sensu lato), linseed (Linum usitatissimum L.), Indian mustard [Brassica juncea (L.) Czernj. & Cosson] and wheat (Triticum aestivum L.). The commensalisms interaction was studied, in which one species benefits, while the other is unaffected, between the crops, M. denticulata and other weeds, to observe the role of medicago as biological control agent of other weeds for enhancement of crop productivity. Further, a statistical test was performed to establish the effect of M. denticulata and weed infestations based on one-step Markov structure of the covariance matrix of the biomass. This permitted development of a mathematical model of a crop-M. denticulata-other weeds system and their interactions through direct and indirect competition for resources. Crops yield decreased considerably due to the presence of other weeds, while it increased due to introduction of medicago and hence medicago acted as a controlling agent in a crop-M. denticulata-other weeds system. Our mathematical analysis supported the experimental findings. The model parameters are estimated through a nonlinear least square and stochastic differential equations. Moreover, some thresholds for the growth of medicago population came out from our analysis that may be used as a biological control threshold for the enhancement of crop productivity.

Preparation of nanocrystalline alpha-Al2O3 using plant fiber

Nanocrystalline alpha-Al2O3 ceramic powders have been prepared from aqueous poly vinyl alcohol (PVA)-aluminum nitrate solution and jute (plant fiber). Soluble Al-ion-PVA solution formed a uniform coating on the surface of jute once it dried completely. Slow hydrolysis of aluminum ion with ammonium hydroxide deposited aluminum hydroxide on the jute surface. Decomposition of the dried aluminum hydroxide-coated jute at high temperature (1150 degrees C/2 hrs) resulted in the formation of single-phase, nanocrystalline alpha-Al2O3 with the corresponding average X-ray and TEM particle size approximately 50 nm. Precursor and heat-treated powders have been characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analysis. This method can be used to produce high-temperature as well as low-temperature nanocrystalline oxides.

A comparative study of classical vs. desmoplastic medulloblastomas

Classical and desmoplastic medulloblastomas (MBs) have been suspected to be biologically different, though comparative studies on markers of biological aggressiveness in these two variants are sparse in the literature. 87 classical and 43 desmoplastic variants of MB were studied with respect to clinical and histological characteristics, MIB-1 labeling index (MIB-1 LI), apoptotic index (AI), ratio of AI to MIB-1 LI, expression of p53 and Bcl-2 protein and 3-year progression-free survival. The only differences documented between the variants were with regard to age distribution and location. Thus, classical histology cases occurred predominantly in children and 80% were midline in location. In contrast, lateral location was seen more frequently with tumors of desmoplastic histology, which occurred in an almost equal distribution between children (56%) and adults (44%). No difference was noted between the variants with regard to proliferation index, apoptotic index, their ratio on or their molecular controls (p53 and Bcl-2). This was reflected in the clinical outcome wherein no significant difference was observed in the 3-year progression-free survival between the variants. It is concluded that the two histological variants of medulloblastoma are not different with regard to biological parameters of aggressiveness. The growth rate and clinical outcome in medulloblastomas have no correlation with the histological variant.

High-lipid diet intake is a possible predisposing factor in the development of hypogonadal osteoporosis

The effects of a high-lipid diet on the intestinal transference of Ca2+ and the activities of intestinal enzymes were studied in ovariectomized rats. The plasma Ca2+ level and urinary loss of Ca2+ were also observed. Ovariectomy decreased both alkaline phosphatase (AP) and calcium ATPase (Ca(2+)-ATPase) activity, and also reduced the mucosal transference of Ca2+ in all parts of the small intestine. Although the plasma Ca2+ level did not change significantly, the urinary loss of Ca2+ was enhanced. A high-lipid diet supplement enhanced all these parameters in ovariectomized rats. It is therefore believed that a high-lipid diet may promote osteoporosis in ovariectomized rats as the result of Ca2+ transfer and enhanced urinary Ca2+ loss.

Mechanism of chloramphenicol-induced modulation of mouse ileal motility

The effect of chloramphenicol (CAP) on the intestinal motility of mice was studied. Acute and chronic CAP treatment significantly increased the food transit time. CAP produced concentration-dependent inhibition of motility of the isolated ileum of mice. Prazosin, propranolol, atropine, ouabain and chlorpromazine all failed to modulate or counteract the CAP-induced inhibition of ileal motility. However, naloxone and hexamethonium slightly modified the inhibitory response of CAP. The inhibitory response of CAP was markedly counteracted by cystine, a guanylate cyclase inhibitor. CAP increased the activity of Ca(++)-ATPase in the ileum in all experiments. Our results suggest that the CAP-induced inhibition of the intestinal motility is not mediated through adrenergic, cholinergic and cAMP or through inhibition of the electrogenic pump. Compared to thiamphenicol (TAP), CAP, with a p-NO2 group in its structure, exhibited more pronounced alteration of both intestinal motility and Ca(++)-ATPase activity. We, therefore, suggest that greater inhibition of ileal motility induced by CAP is possibly a p-NO2-cGMP-Ca(++)-ATPase-mediated mechanism.

Mechanism of inhibition of smooth muscle of guinea-pig taenia coli by chloramphenicol

The effects of antibiotic chloramphenicol (CAP) on Ca(2+)-ATPase activity and muscle tension were examined in guinea-pig taenia coli. In general, when CAP was added to the resting tissue no inhibition was observed except when a tonus was present, caused by either ouabain, high K+ or acetylcholine. Ouabain and high K(+)-induced sustained contractions were concentration-dependently inhibited by CAP. The sustained contraction induced by high K+ was more strongly inhibited by CAP than ouabain (IC50 value: high K+ 0.29 mumol/ml; ouabain 0.34 mumol/ml). In Ca(2+)-free solution, inhibition of ouabain-induced sustained contracture by CAP was more pronounced. CAP increased the activity of Ca(2+)-ATPase in taenia coli in all experiments. In presence of cystine, CAP-induced inhibition and increase in Ca(2+)-ATPase activity could not be observed. CAP analogue thiamphenicol (TAP), devoid of p-NO2 group, showed insignificant response on smooth muscle inhibition and Ca(2+)-ATPase activity. These findings suggest that CAP inhibits smooth muscle contractility by decreasing cytosolic Ca2+ ([Ca2+]i) level through a cGMP mediated increase in Ca(2+)-ATPase activity and this action is possibly related with the p-NO2 group present in its molecule like other nitro-compounds.

The effect of chloramphenicol on mucosal transference of glucose in mice; the role of intestinal alkaline phosphatase in this process

The effect of chloramphenicol (CAP) on the mucosal transference of glucose in mice and its relation with the activities of different small intestinal enzymes were studied. CAP produced an increase in the mucosal transference of glucose in jejunum and a decrease in ileum. However, CAP reduced the activity of Na(+)-K(+)-ATPase in both of these segments. Treatment with ouabain could not alter the effects of CAP. Under similar experimental conditions, the activity of alkaline phosphatase (AP) was reduced in jejunum but increased in ileum. In presence of theophylline, the CAP-induced increase in the transference in jejunum was further enhanced, whereas in acute experiments with ileum theophylline counteracted the reduced transference to the control level. In presence of Zn2+, CAP-induced changes in jejunum were reversed whereas in ileum the decrease was more pronounced. Like AP, CAP altered the activity of Ca(2+)-ATPase in both segments. It is proposed that in presence of CAP an inverse relationship exists between the activity of AP and the glucose transference in these segments. It is further revealed that such differential changes in the transference of glucose may be due to site specific alterations in the activity of AP.