Search

The electromagnetic interference shielding and microwave attenuation capabilities of ZnO semiconductor nanocomposites have recently been improved using a variety of approaches by correctly modifying their permittivity. To improve microwave attenuation, ZnO semiconductor nanostructures have been combined with graphene, multi-wall carbon nanotubes, metal nanoparticles and their alloys, two-dimensional MXene, spinel ferrite magnetic nanoparticles, polymer systems, and textiles. This paper covers the opportunities and constraints that these cutting-edge nanocomposites in the field of electromagnetic wave absorption encounter as well as the research progress of ZnO semiconductor-based nanocomposite. The structure-function relationship of electromagnetic wave absorption nanocomposites, design strategies, synthesis techniques, and various types of advanced nanocomposites based on ZnO semiconductor are also covered. In order to design and prepare high efficiency ZnO semiconductor based electromagnetic wave absorbing materials for use in applications of next-generation electronics and aerospace, this article can offer some useful ideas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Microbial fuel cell (MFC) is a promising alternative to energy-intensive conventional wastewater technology. However, poor electron transfer efficiency, low coulombic recovery (CR), and high capital cost highly restricted its practical application. In this work, spatial electroactive biofilm is successfully developed on the carbonaceous skeleton derived from phenolic foam, which highly improved the bio-capacitance and Geobacter abundance of bioanode. Compared with carbon cloth (CC) anode, the optimal spatial electroactive biofilm (3DP_900) enriched the Geobacter abundance up to 56.8% from 17.2%, and obtained an extraordinary electroactive biomass loading of about 339 ± 63 μg cm -2 and a remarkable bio-capacitance of about 3.4 F. In general, spatial biofilm highly reduces the barriers to electron transfer (R ct ) and mass transfer (R d ) in anodic substrate oxidation reaction and obtains the lowest R ct of 2.0 ± 0.2 Ω and R d of 35 ± 3.3 Ω in 3DP_900, which also supports the highest power density at 0.347 ± 0.027 W m -2 and the highest CR at 69.2%. More importantly, due to its mature preparation technology, carbonized phenolic foam (2 cm thick pieces) reduces the capital cost of electrode preparation by three orders of magnitude from 1157.3 USD m -2 of CC to 5.2 USD m -2 . Overall, this work offers an effective and scalable electrode to achieve high substrate utilization rate and energy recovery efficiency, and considers the economic cost of electrode fabrication for the further construction of pilot-scale MFCs equipment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In this paper, we have studied the structural, optical, dielectric and magnetic properties of Eu 3+ , Bi 3+ co-doped LaVO 4 phosphors prepared by solid state reaction method. Rietveld structural analysis of the samples confirms the monoclinic crystal structure with P2 1 /n space group. The particles size of Eu 3+ doped LaVO 4 phosphor increased in presence of Bi 3+ ion. The excitation spectrum of Eu 3+ , Bi 3+ co-doped LaVO 4 phosphor reveals bands due to charge transfer state (CTS) and electronic transitions of Eu 3+ and Bi 3+ ions. The Eu 3+ doped LaVO 4 phosphor gives intense red emission centred at 613 nm due to 5 D 0  →  7 F 2 transition of Eu 3+ ion excited at 266, 355 and 394 nm wavelengths. When Bi 3+ and Eu 3+ ions are co-doped in the LaVO 4 phosphor the photoluminescence intensity is enhanced upto two times. The photoluminescence intensity is largest for the 266 nm excitation. This is due to energy transfer from CTS and ( 1 P 1 , 3 P 1 ) levels of the Bi 3+ ion to 5 D 4 level of the Eu 3+ ion and increase in the particles size of phosphor. The Eu 3+ , Bi 3+ co-doped LaVO 4 phosphors also show excellent dielectric and magnetic properties with a variation in frequency and magnetic field, respectively. Thus, the Eu 3+ , Bi 3+ co-doped LaVO 4 phosphor may be useful in fabricating displays devices, red emitting phosphors, dielectric capacitors and magnetic devices., Competing Interests: Declaration of competing interest This article is free from conflicts of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Pesticide lifecycle management encompasses a range of elements from legislation, regulation, manufacturing, application, risk reduction, monitoring, and enforcement to disposal of pesticide waste. A survey was conducted in 2017-2018 to describe the contemporary global status of pesticide lifecycle management, to identify where the gaps are found. A three-tiered questionnaire was distributed to government entities in 194 countries. The response rate was 29%, 27% and 48% to the first, second and third part of the questionnaire, respectively. The results showed gaps for most of the selected indicators of pesticide management, suggesting that pesticide efficacy and safety to human health and the environment are likely being compromised at various stages of the pesticide lifecycle, and at varying degrees across the globe. Low-income countries generally had the highest incidence of gaps. Particular shortcomings were deficiencies in pesticide legislation, inadequate capacity for pesticide registration, protection against occupational exposure to pesticides, consumer protection against residues in food, and environmental protection against pesticide contamination. Policy support for, and implementation of, pesticide use-reduction strategies such as integrated pest management and integrated vector management has been inadequate across regions. Priority actions for structural improvement in pesticide lifecycle management are proposed, including pesticide use-reduction strategies, targeted interventions, and resource mobilization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier B.V.)

The Pr(3+)/Yb(3+) co-doped La2O3 and La(OH)3 nano-phosphors have been synthesized through solution combustion method. The structure and morphology of the samples have been studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The physical and optical properties of the samples have been measured and compared. A broad intense infrared emission centered at 850nm due to (1)I6→(1)G4 transition along with sharp green emission centerd at 513nm due to (3)P0→(3)H4 transition are observed on excitation with 976nm laser. The emission intensity of Pr(3+) is optimized with concentration and it is maximum at 0.08mol%. The annealed samples are found to be more crystalline and emit larger photoluminescence due to removal of quenching centers. The power dependent study of green upconversion emission indicates the involvement of two photons. The phosphor in La(OH)3 phase is more stable though the photoluminescence emission is slightly weak. La(OH)3 is less toxic compared to La2O3 and is biocompatible. It generates more heat and can be used in biothermal treatment., (Copyright © 2015 Elsevier B.V. All rights reserved.)

We report the structural and optical properties of Yb(3+), Pr(3+) co-doped Y2O3 nano-phosphor synthesized through solution combustion method. The structural studies reveal the nano-crystalline structure of the sample. The energy dispersive spectroscopy (EDS) measurements confirm the presence of Y, O, Pr and Yb elements in the sample. Fourier transform infrared studies show the vibrational features of the samples. The fluorescence spectra of the samples have been monitored on excitation with 976 nm and the intense green upconversion emission observed at 552 nm is due to (3)P0→(3)H5 electronic transition. The concentration of Pr(3+) ion in the sample is optimized and the fluorescence intensity is maximum at 0.08 mol% of Pr(3+). The power dependence studies reveal the involvement of two photons in the emission process. The possible mechanism of upconversion has been discussed on the basis of schematic energy level diagram. The sample annealed at higher temperature enhances the fluorescence intensity up to 8 times and this enhancement is discussed in terms of the removal of optical quenching centers. The nano-phosphor can be applicable in the field of display devices and green laser., (Copyright © 2014 Elsevier B.V. All rights reserved.)

We report Eu3+, Sm3+ co-doped La(OH)3 nano-crystalline red emitting phosphor prepared following combustion synthesis protocol. The structural and morphological information about the synthesized samples have been explored using X-ray diffraction (XRD) and transmission electron microscopic (TEM) techniques. The optical properties of the samples have been investigated under 355 nm laser excitations. The sample emits intense red emissions at 625 and 707 nm due to 5D0→7F2 and 5D0→7F4 transitions in Eu3+ ion, respectively. The concentrations of both, Eu3+ and Sm3+ in the samples were optimized at 1 mol% to get maximum fluorescence. The presence of Sm3+ in the Eu3+ doped sample enhances the emission intensity up to two times. The samples annealed at higher temperature show significant enhancement in the emission intensity. The life time studies show an efficient energy transfer from Sm3+ to Eu3+ ions and have been discussed with the help of schematic energy level diagram. This enhancement in the emission intensity is discussed in terms of the rare earth ion concentration, annealing temperature and energy transfer., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: Injecting drug use is the primary mode of HIV transmission and acquisition in Afghanistan. People who inject drugs (PWID) in the country have been characterized by high risk injecting behavior and a high burden of HCV infection. We aimed to estimate the burden of HIV, HCV, and other infectious diseases and to identify the correlates of HIV and HCV infection among PWID living in three major Afghan cities in 2009., Methods: Epidemiologic data was collected among PWID for the integrated biological and behavioral surveillance (IBBS) survey between May and August, 2009 in three Afghan cities. Data were collected using a structured questionnaire and biologic specimens to screen for HIV, HBV, HCV, syphilis, and HSV-2 using rapid testing kits. Multiple logistic regression models were constructed to identify correlates of infection., Results: Among 548 participants, pooled HIV prevalence was 7.1% (Mazar-i-Sharif: 1.0%, Kabul: 3.1%, Herat: 18.4%) and HCV prevalence was 40.3%. Almost all participants with HIV infection were co-infected with HCV (94.9%). Pooled prevalence estimates for other diseases included 7.1% for HBV, 5.5% for syphilis; and 9.3% for HSV-2. Living in Herat, ever in prison and time injecting were independently associated with HIV infection. Living in Kabul, Herat and time injecting were independently associated with HCV infection., Conclusions: There is a high and heterogeneous burden of HIV and HCV among PWID in Afghan cities. Provision of comprehensive harm reduction services to PWID in Afghanistan is warranted to reduce exposures associated with HIV and HCV infection, especially in the city of Herat., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

In the present work, Sm(3+) doped La(OH)(3) nano-phosphor (~40 nm) has been synthesized using combustion synthesis method and detailed structural and spectroscopic characterizations are carried out. On excitation with 532 nm, several photoluminescence peaks extending over green to NIR regions have been observed and assigned to be due to 4f-4f transitions of Sm(3+) ions. A bright orange-red perception is observed in annealed sample, which is 10 times higher than as synthesized sample. Time resolved emission spectroscopy reveals pronounced effect of heating, which induce good crystalline in the host., (Copyright © 2012 Elsevier B.V. All rights reserved.)

In view of extensive uses of lambda-cyhalothrin, a new generation type II synthetic pyrethroid, human exposure is quite imminent. The present study has therefore been carried out to investigate effect of lambda-cyhalothrin on brain dopaminergic and serotonergic systems and functional alterations associated with them. Post-lactational exposure to lambda-cyhalothrin (1.0 mg/kg or 3.0 mg/kg body weight, p.o.) from PD22 to PD49 caused a significant decrease in the motor activity and rota-rod performance in rats on PD50 as compared to controls. Decrease in motor activity in lambda-cyhalothrin treated rats was found to persist 15 days after withdrawal of exposure on PD65 while a trend of recovery in rota-rod performance was observed. A decrease in the binding of ³H-Spiperone, known to label dopamine-D2 receptors in corpus striatum associated with decreased expression of tyrosine hydroxylase (TH)-immunoreactivity and TH protein was observed in lambda-cyhalothrin treated rats on PD50 and PD65 compared to controls. Increase in the binding of ³H-Ketanserin, known to label serotonin-2A receptors in frontal cortex was observed in lambda-cyhalothrin exposed rats on PD50 and PD65 as compared to respective controls. The changes were more marked in rats exposed to lambda-cyhalothrin at a higher dose (3.0 mg/kg) and persisted even 15 days after withdrawal of exposure. The results exhibit vulnerability of developing rats to lambda-cyhalothrin and suggest that striatal dopaminergic system is a target of lambda-cyhalothrin. Involvement of serotonin-2A receptors in the neurotoxicity of lambda-cyhalothrin is also suggested. The results further indicate that neurobehavioral changes may be more intense in case exposure to lambda-cyhalothrin continues., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Present "green" synthesis is an efficient, easy-going, fast, renewable, inexpensive, eco-friendly and non-toxic approach for nanosilver formation, which offers numerous benefits over physiochemical approaches. The X-ray diffraction (XRD) pattern suggests the formation and crystallinity of nanosilver. The average particle size of silver nanoparticles was 8.25±1.37 nm as confirmed by transmission electron microscopy (TEM). The UV-vis absorption spectrum shows a characteristic absorption peak of silver nanoparticles at 410 nm. FTIR confirms Azadirachtin as reducing and stabilizing agent for nanosilver formation. In addition, the nanosilver modified electrode (Ag/GC) exhibited an excellent electro-catalytic activity toward the reduction of hydrogen peroxide (H(2)O(2)). The produced nanosilver is stable and comparable in size. These silver nanoparticles show potential applications in the field of sensors, catalysis, fuel cells and nanodevices., (Copyright © 2012 Elsevier B.V. All rights reserved.)

In total, 129 Plasmodium vivax isolates from different geographical areas in India were analysed for point mutations in the P. vivax dihydrofolate reductase gene that were associated with pyrimethamine resistance. A gradual increase in the frequency of mutant genotypes was observed from north to south (p <0.0001). In the northern region (Delhi, Panna and Nadiad), the wild-type genotype was most prevalent, while the mutant genotype predominated in the coastal regions of southern India (Navi Mumbai, Goa and Chennai). Isolates from the Car-Nicobar islands showed only mutant genotypes. The differential geographical pattern of mutations may be associated with the transmission pattern.

Camel lactoferrin is the first protein from the transferrin superfamily that has been found to display the characteristic functions of iron binding and release of lactoferrin as well as transferrin simultaneously. It was remarkable to observe a wide pH demarcation in the release of iron from two lobes. It loses 50 % iron at pH 6.5 and the remaining 50 % iron is released only at pH values between 4.0 and 2.0. Furthermore, proteolytically generated N and C-lobes of camel lactoferrin showed that the C-lobe lost iron at pH 6.5, while the N-lobe lost it only at pH less than 4.0. In order to establish the structural basis of this striking observation, the purified camel apolactoferrin was crystallized. The crystals belong to monoclinic space group C2 with unit cell dimensions a=175.8 A, b=80.9 A, c=56.4 A, beta=92.4 degrees and Z=4. The structure has been determined by the molecular replacement method and refined to an R-factor of 0.198 (R-free=0.268) using all the data in the resolution range of 20.0-2.6 A. The overall structure of camel apolactoferrin folds into two lobes which contain four distinct domains. Both lobes adopt open conformations indicating wide distances between the iron binding residues in the native iron-free form of lactoferrin. The dispositions of various residues of the iron binding pocket of the N-lobe of camel apolactoferrin are similar to those of the N-lobe in human apolactoferrin, while the corresponding residues in the C-lobe show a striking similarity with those in the C-lobes of duck and hen apo-ovotransferrins. These observations indicate that the N-lobe of camel apolactoferrin is structurally very similar to the N-lobe of human apolactoferrin and the structure of the C-lobe of camel apolactoferrin matches closely with those of the hen and duck apo-ovotransferrins. These observations suggest that the iron binding and releasing behaviour of the N-lobe of camel lactoferrin is similar to that of the N-lobe of human lactoferrin, whereas that of the C-lobe resembles those of the C-lobes of duck and hen apo-ovotransferrins. Hence, it correlates with the observation of the N-lobe of camel lactoferrin losing iron at a low pH (4.0-2.0) as in other lactoferrins. On the other hand, the C-lobe of camel lactoferrin loses iron at higher pH (7.0-6.0) like transferrins suggesting its functional similarity to that of transferrins. Thus, camel lactoferrin can be termed as half lactoferrin and half transferrin., (Copyright 2001 Academic Press.)