Interfacial engineering in 3D/2D and 1D/2D bismuth ferrite (BiFeO3)/Graphene oxide nanocomposites for the enhanced photocatalytic activities under sunlight.

3D-particulate and 1D-fiber structures of multiferroic bismuth ferrite (BiFeO3/BFO) and their composites with 2D-graphene oxide (GO) have been developed to exploit the different scheme of interfacial engineering as 3D/2D and 1D/2D systems. Particulates and fibers of BFO were developed via sol-gel and electrospinning fabrication approaches respectively and their integration with GO was performed via the ultrasonic-assisted chemical reduction process. The crystalline and phase formation of BiFeO3 and GO was confirmed from the XRD patterns obtained. The electron microscopic images revealed the characteristic integration of 3D particulates (with average size of 100 nm) and 1D fibers (with diameter of ~150 nm and few µm length) onto the 2D GO layers (thickness of ~27 nm). XPS analysis revealed that the BFO nanostructures have been integrated onto the GO through chemisorptions process, where it indicated that the ultrasonic process engineers the interface through the chemical modification of the surface of these 3D/2D and 1D/2D nanostructures. The photophysical studies such as the impedance and photocurrent measurements showed that the charge separation and recombination resistance is significantly enhanced in the system, which can directly be attributed to the effective interfacial engineering in the developed hetero-morphological composites. The degradation studies against a model pollutant Rhodamine B revealed that the developed nanocomposites exhibit superior photocatalytic activity via the effective generation of OH radicals as confirmed by the radical analysis studies (100% degradation in 150 and 90 min for 15% GO/BFO particulate and fiber composites, respectively). The developed system also demonstrated excellent photocatalytic recyclability, indicated their enhanced stability.

Multidentate ligand approach for conjugation of perovskite quantum dots to biomolecules.

Building compatible surface on perovskite quantum dots (PQDs) for applications like sensing analytes in aqueous medium is highly challenging and if achieved by simple means can revolutionize disease diagnostics. The present work reports the surface engineering of CsPbBr3 QDs via "simple ligand exchange process" to achieve water-compatible QDs towards detection of biomolecules. The monodentate oleic acid ligand in CsPbBr3 QDs is exchanged with dicarboxylic acid containing (bidentate) ligands such as folic acid (FA), ethylenediamine tetra-acetic acid (EDTA), succinic acid (SA) and glutamic acid (GA) to develop an efficient water-compatible PQD-ligand system. optical and theoretical studies showed the existence of a stronger binding between the perovskite and succinic acid ligand as compared to oleic acid (OA) and all other ligands. Replacement of OA with SA and retention of crystal structure is validated using spectroscopic and microscopic tools. It is observed that SA ligands facilitate better electronic coupling with PQDs and show significant improvement in fluorescence and stability. Further N-Hydroxy succinimide (NHS), which is a well-known compound to activate carboxyl groups, is used to bind onto SA PQDs as multidentate ligand, to form water stable PQDs. SA PQDs react with NHS (in water) to form multidentate ligand passivated PQDs that show very high photoluminescence (PL) as compared to OA PQDs in toluene. This also results in the formation of an NHS ester that allows bioconjugation with PQDs. This simple probe in water is further utilized for sensing a highly hydrophilic bovine serum albumin (BSA) protein as a model target to demonstrate the potential and effectiveness of this process to create compatible QDs for the successful conjugation of biomolecules. Although the focus of this work is to demonstrate bioconjugation and not achieving higher sensitivity levels, the intrinsic sensing level of these compatible QDs towards BSA shows a detection limit of 51.47 nM, which is above par with other reports in literature.

Optimization of N doping in TiO2 nanotubes for the enhanced solar light mediated photocatalytic H2 production and dye degradation.

Herein, we report the optimization of nitrogen (N) doping in TiO2 nanotubes to achieve the enhanced photocatalytic efficiencies in degradation of dye and H2 gas evolution under solar light exposure. TiO2 nanotubes have been produced via hydrothermal process and N doping has been tuned by varying the concentration of urea, being the source for N, by solid-state dispersion process. The structural analysis using XRD showed the characteristic occupancy of N into the structure of TiO2 and the XPS studies showed the existence of Ti-N-Ti network in the N-doped TiO2 nanotubes. The obtained TEM images showed the formation of 1D tube-like structure of TiO2. Diffuse reflectance UV-Vis absorption spectra demonstrated that the N-doped TiO2 nanotubes can efficiently absorb the photons of UV-Vis light of the solar light. The optimized N-doped TiO2 nanotubes (TiO2 nanotubes vs urea @ 1:1 ratio) showed the highest degradation efficiency over methyl orange dye (∼91% in 90 min) and showed the highest rate of H2 evolution (∼19,848 µmol h-1.g-1) under solar light irradiation. Further, the recyclability studies indicated the excellent stability of the photocatalyst for the durable use in both the photocatalytic processes. The observed efficiency was ascribed to the optimized doping of N-atoms into the lattices of TiO2, which enhanced the optical properties by forming new energy levels of N atoms near the valence band maximum of TiO2, thereby increased the overall charge separation and recombination resistance in the system. The improved reusability of photocatalyst is attributed to the doping-induced structural stability in N-doped TiO2. From the observed results, it has been recognized that the established strategy could be promising for synthesizing N-doped TiO2 nanotubes with favorable structural, optical and photocatalytic properties towards dye degradation and hydrogen production applications.

Recent case studies on the use of ozone to combat coronavirus: Problems and perspectives.

Coronavirus pandemic has created havoc in the world. COVID-19 is now officially labeled as Severe Acute Respiratory Syndrome-related Coronavirus-SARS-CoV-2. Therefore, it is equally important to combat the virus both inside the human body as well as in the environment. These viruses, being RNA viruses, are found to be susceptible to ozone. Ozone being an unstable molecule can breakup into its split products namely reactive oxygen species and ozonides creating a toxic environment for these viruses. Ozone mainly prevents the membrane fusion with the host cell, thus interfering with their replication. With vast applications of the gas, it has created a new spark in the field of medicine in combating these viruses and many other organisms. In this context, this article provides insights from recent clinical and research studies on the problems and possibilities in employing the ozone to combat the coronaviruses.

Correction: Compliments of confinements: substitution and dimension induced magnetic origin and band-bending mediated photocatalytic enhancements in Bi1-xDyxFeO3 particulate and fiber nanostructures.

Correction for 'Compliments of confinements: substitution and dimension induced magnetic origin and band-bending mediated photocatalytic enhancements in Bi1-xDyxFeO3 particulate and fiber nanostructures' by M. Sakar et al., Nanoscale, 2015, 7, 10667-10679.

Adaptive locomotion of artificial microswimmers.

Bacteria can exploit mechanics to display remarkable plasticity in response to locally changing physical and chemical conditions. Compliant structures play a notable role in their taxis behavior, specifically for navigation inside complex and structured environments. Bioinspired mechanisms with rationally designed architectures capable of large, nonlinear deformation present opportunities for introducing autonomy into engineered small-scale devices. This work analyzes the effect of hydrodynamic forces and rheology of local surroundings on swimming at low Reynolds number, identifies the challenges and benefits of using elastohydrodynamic coupling in locomotion, and further develops a suite of machinery for building untethered microrobots with self-regulated mobility. We demonstrate that coupling the structural and magnetic properties of artificial microswimmers with the dynamic properties of the fluid leads to adaptive locomotion in the absence of on-board sensors.

Materials and Mechanisms of Photo-Assisted Chemical Reactions under Light and Dark Conditions: Can†Day-Night Photocatalysis Be Achieved?

The photoassisted catalytic reaction, conventionally known as photocatalysis, is expanding into the field of energy and environmental applications. It is widely known that the discovery of TiO2 -assisted photochemical reactions has led to several unique applications, such as degradation of pollutants in water and air, hydrogen production through water splitting, fuel conversion, cancer treatment, antibacterial activity, self-cleaning glasses, and concrete. These multifaceted applications of this phenomenon can be enriched and expanded further if this process is equipped with more tools and functions. The term "photoassisted" catalytic reactions clearly emphasizes that photons are required to activate the catalyst; this can be transcended even into the dark if electrons are stored in the material for the later use to continue the catalytic reactions in the absence of light. This can be achieved by equipping the photocatalyst with an electron-storage material to overcome current limitations in photoassisted catalytic reactions. In this context, this article sheds lights on the materials and mechanisms of photocatalytic reactions under light and dark conditions. The manifestation of such systems could be an unparalleled technology in the near future that could influence all spheres of the catalytic sciences.

Ni supported CdIn2S4 spongy-like spheres: a noble metal free high-performance sunlight driven photocatalyst for hydrogen production.

Nickel supported CdIn2S4 (Ni-CIS) spongy-like spheres have been developed using alcoholysis followed by a sulfidation process. The formation of nanocrystalline-single phase CdIn2S4 was confirmed using X-ray diffraction studies. Electron microscopy images showed that the spongy-like spheres are composed of CdIn2S4 nanoparticles with average sizes of around 25 nm. X-ray photoelectron spectra indicated the presence of elements with their respective stable oxidation states that led to the formation of single phase CdIn2S4 with enhanced structural integrity and chemical composition. The absorption spectra indicated the visible light activity of the material and the band gap energy is deduced to be 2.23 eV. The photocatalytic efficiency of the synthesized Ni-CIS in relation to its ability to produce hydrogen under solar light irradiation is estimated to be 1060 µmol g-1 h-1, which is around 5.5 and 3.6 fold higher than that of Pt-CIS (180 µmol g-1 h-1) and Pd-CIS (290 µmol g-1 h-1), respectively, as obtained in this study. Accordingly, the mechanism of the observed efficiency of the Ni-CIS nanoparticles is also proposed. The recyclability test showed consistent hydrogen evolution efficiency over 3 cycles (9 h), which essentially revealed the excellent photo- and chemical-stability of the photocatalyst. The strategy to utilize non-noble metals such as Ni, rather than noble-metals, as a co-catalyst opens up a new possibility to develop low cost and high-performance sunlight-driven photocatalysts as achieved in this study.

The role of ovarian reserve markers in prediction of clinical pregnancy.

To evaluate the role of ovarian reserve markers in the prediction of clinical pregnancy and embryo transfer accomplishment among poor responder IVF applicants. 304 female poor responder IVF applicants were included in this prospective cohort study conducted at the IVF-unit. Antral follicle count, FSH, LH, E2, AMH and IVF outcomes were compared in pregnant and non-pregnant groups as well as in ET vs. non-ET groups. The number of retrieved oocytes was significantly correlated positively with AMH and AFC, and negatively with FSH and age. Quartiles of FSH and AFC were similar to the rate of pregnancy. Quartiles of AMH (<25%/25-75% and <25%/>75%) were statistically significant. Mean serum levels for AMH were significantly lower in the non-ET group. Our findings seem to indicate that day 3 AMH values can predict ET accomplishment with a sensitivity of 96% and a specificity of 35%. Quartiles of AMH <25% (< 0.21 ng/mL) can predict the IVF results among poor responder IVF applicants. Impact statement Various cut-off values have been determined for day 3 serum AMH values. These values help to determine the groups that are expected to give normal, high or low response to stimulation and decide the treatment options. In contrast to other groups of patients, poor responders cannot reach the embryo transfer stage for several reasons. These are; absence of a mature oocyte after oocyte pick-up, fertilisation failure without male factor or poor embryo quality. In the present study; a cut-off value of 0.33 ng/mL for the prediction of ET accomplishment in poor responder patients was determined with a sensitivity of 96%. Additionally, clinical pregnancy could not be achieved under the value of 0.21 ng/mL day 3 AMH values. It is important to clarify the embryo transfer success of poor responder patients prior to expected treatment success. Pre-treatment counselling for these patients would lessen the disappointment that may develop after treatment. The cost-effectiveness of treatments below these AMH values can be determined by further studies.

Importance of cervical length in dysmenorrhoea aetiology.

The objective of this prospective case-control study was to determine whether uterine corpus and cervical length measurements have a role in dysmenorrhoea aetiology in virgins. Patients with severe primary dysmenorrhoea with visual analog scale scores of ≥7 composed the dysmenorrhoea group (n = 51), while the control group (n = 51) was of women with painless menstrual cycles or with mild pain. Longitudinal and transverse axes of the uterine cervix and uterine corpus were measured. Correlation between severity of dysmenorrhoea and uterine cervix and corpus axes was calculated. Longitudinal and transverse axes of uterine cervix as well as uterine cervix volume were significantly higher in the dysmenorrhoea group compared to the controls. There was a significant positive correlation between severity of dysmenorrhoea and the length of cervical longitudinal and transverse axes and uterine cervical volume. Our findings reveal longer cervical length and greater cervical volume in young virgin patients with dysmenorrhoea and severe pain compared to those with no or less pain.

Is there an effect of thyroid autoimmunity on the outcomes of assisted reproduction?

We aimed to evaluate the role of thyroid autoantibodies (TAA) on the outcomes of intracytoplasmic sperm injection-embryo transfer (ICSI-ET). A prospective case-control study was conducted in the in vitro fertilisation (IVF) centre of Suleymaniye Maternity Training and Research Hospital, Istanbul, Turkey between July 2013 and March 2014. A total of 49 (19.52%) TAA-positive and 202 TAA-negative patients were enrolled. Demographic characteristics and laboratory parameters were recorded. All patients underwent ICSI-ET. Thirty-one TAA-positive patients (32 cycles) and 121 TAA-negative patients (126 cycles) completed the study. Mean female age, body mass index (BMI), type of infertility, duration of infertility, antral follicle count (AFC), anti-Müllerian hormone (AMH), basal follicle stimulating hormone (bFSH), luteinising hormone (bLH), and oestradiol (bE2), prolactin and thyroid hormone profiles, male age and aetiology of infertility of both groups were similar (p > 0.05). There was no significant difference between groups in terms of duration and dose of gonadotropin (Gn) therapy, day of human chorionic Gn (hCG) administration, serum E2 and progesterone levels, number of collected oocytes, ratio of fertilisation, number of available embryos, positive pregnancy test, biochemical pregnancy, clinical pregnancy, ratio of miscarriage and ongoing pregnancy (p > 0.05). In conclusion, we failed to demonstrate a significant role of TAA on the outcomes of ICSI-ET in euthyroid patients. Further studies with larger numbers of participants are required to clarify these data.

The effect of Ramadan fasting and maternal hypoalbuminaemia on neonatal anthropometric parameters and placental weight.

In Islamic religion, daytime fasting during the month called Ramadan is an annual practice. In this study, we aimed to investigate the effect of Ramadan fasting and maternal hypoalbuminaemia on neonatal growth parameters. A prospective case-control study was conducted in Diyarbakir and Istanbul, Turkey. The sample size of fasting group was 168 and that of non-fasting group was 170. Demographic characteristics, obstetrics ultrasonographic findings and laboratory parameters of the participants were recorded. Neonatal anthropometric parameters and placental weight were noted. The mean placental weight was significantly higher in the fasting group (p = 0.037). Also, in the fasting group, pregnant women with hypoalbuminaemia had significantly higher placental weight (p = 0.009). In conclusion, the mean placental weight in the fasting group was significantly higher. Also a significant correlation between placental weight and maternal serum albumin level was observed in the fasting group.

Particulates vs. fibers: dimension featured magnetic and visible light driven photocatalytic properties of Sc modified multiferroic bismuth ferrite nanostructures.

We report the magnetic and visible light driven photocatalytic properties of scandium (Sc) substituted bismuth ferrite (BSFO) particulate and fiber nanostructures. An increasing concentration of Sc was found to reduce the crystallite size, particle size and band gap energy of the BSFO nanostructures, which was evident from X-ray diffraction, field emission scanning electron microscopy and UV-Visible diffuse reflectance spectroscopy analysis respectively. The temperature dependent magnetic studies carried out using a SQUID magnetometer suggested that the origin of the magnetic properties in the pure BFO system could be the emergence of an antiferromagnetic-core/ferromagnetic-shell like structure, in contrast to the modified spin canted structures in the case of the BSFO nanostructures. The observed photocatalytic efficiency was attributed to the enhanced band bending process and recombination resistance in the BSFO nanostructures. For a comparative study, the photocatalytic activities of some selected compositions were also investigated under simulated solar light along with natural solar light.

Compliments of confinements: substitution and dimension induced magnetic origin and band-bending mediated photocatalytic enhancements in Bi(1-x)Dy(x)FeO3 particulate and fiber nanostructures.

The manifestation of substitution and dimension induced modifications in the magnetic origin and photocatalytic properties of Dy substituted bismuth ferrite (BDFOx) particulate and fiber nanostructures are reported herein. A gradual transformation from rhombohedral to orthorhombic structure is observed in BFO with the increasing concentration of Dy. Substitution induced size reduction in particulate and fiber nanostructures is evident from the scanning and transmission electron micrographs. Energy band structures of both particulate and fiber nanostructures are considerably influenced by the Dy substitution, which is ascribed to the formation of new energy states underneath the conduction band of host BFO. Field dependent and temperature dependent magnetic studies reveal that the origin of magnetism in pure BFO systems is due to the antiferromagnetic-core/ferromagnetic-shell like structure. On the other hand, it gets completely switched into 'canted' spin structures due to the substitution induced suppression of cycloidal spins in BFO, which is found to be the origin of magnetism in BDFOx particulate and fiber nanostructures. The visible light driven photocatalytic activity of BDFOx nanostructures is found to be enhanced with increasing concentration of Dy. Substitution induced band gap modification, semiconductor band bending phenomenon mediated charge transfer and reduced recombination resistances are attributed to the observed photocatalytic enhancements in these nanostructures.

Versatility of electrospinning in the fabrication of fibrous mat and mesh nanostructures of bismuth ferrite (BiFeO3) and their magnetic and photocatalytic activities.

This study demonstrates the fabrication of electrospun bismuth ferrite (BiFeO3/BFO) fiber mat and fibrous mesh nanostructures consisting of aligned and random fibers respectively. The formation of these one dimensional (1D) nanostructures was mediated by the drum and plate collectors in the electrospinning process that yielded aligned and random nanofibers of BFO respectively. The single phase and rhombohedral crystal structure of the fabricated 1D BFO nanostructures are confirmed through X-ray diffraction (XRD) studies. X-ray photoelectron spectroscopy (XPS) studies indicated that the fabricated fibers are stoichiometric BFO with native oxidation states +3. The surface texture and morphology are analyzed using the field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) techniques. The average size of fibers in mat and mesh nanostructures is found to be 200 nm and 150 nm respectively. The band gap energy of BFO mat and mesh deduced from their UV diffuse reflectance spectra (UV-DRS) was found to be 2.44 eV and 2.39 eV, respectively, which evidenced the improved visible light receptivity of BFO mesh compared to that of the mat. Magnetization studies using a super conducting quantum interference device (SQUID) magnetometer revealed the weak ferromagnetic properties of BFO mesh and mat nanostructures that could emerge due to the dimension induced suppression of cycloidal spin structures. The photocatalytic degradation properties of the fibrous mesh are found to be enhanced compared to that of the mat. This could be attributed to the reduced band gap energy and an improved semiconductor band-bending phenomenon in the mesh that favoured the transportation of excited charge carriers to the photocatalyst-dye interfaces and the production of more number of reactive species that lead to the effective degradation of the dye molecules.

Role of oxygen vacancy and Fe-O-Fe bond angle in compositional, magnetic, and dielectric relaxation on Eu-substituted BiFeO(3) nanoparticles.

The influence of oxygen vacancies on the dielectric relaxation behavior of pure and Eu-substituted BiFeO3 nanoparticles synthesized by a sol-gel technique has been studied using impedance spectroscopy in the temperature range of 90 °C to 180 °C. The electric relaxation time and activation energy of the oxygen vacancies can be calculated from the Arrhenius equation, and found to be 1.26 eV and 1.76 eV for pure and Eu-substituted BiFeO3, respectively. Substitution induces structural disorder and changes in the Fe-O-Fe bond angle, leading to alteration of the magnetic properties, observed from magnetic studies and evaluated using Rietveld refinement of the XRD patterns. X-ray photoelectron spectroscopy (XPS) confirms the shifting of the binding energy of the Bi 4f orbital, establishing Eu substitution at the Bi site. Calculation of the area under the Fe(2+)/Fe(3+) (2p) and O (1s) XPS spectra gives approximate values of the oxygen vacancies.

Noninvasive assessment of subclinical atherosclerosis in normotensive gravidae with gestational diabetes.

AIM: Carotid artery intima-media thickness (CIMT), hyperhomocysteinemia, microalbuminuria, and nitric oxide reflect subclinical atherosclerosis and predict the risk of future cardiovascular events. We aimed to evaluate the presence of subclinical atherosclerosis and endothelial dysfunction in normotensive patients with gestational diabetes mellitus (GDM) noninvasively. PATIENTS AND METHODS: We enrolled 41 normotensive patients with GDM and 44 healthy gravidae in the study. Serum homocysteine and nitric oxide levels, urinary albumin excretion (microalbuminuria), and CIMT were evaluated along with lipid parameters and anthropometric measurements. RESULTS: Patients with GDM had significantly higher levels of serum homocysteine, urinary albumin excretion, and increased CIMT (p < 0.001, p=0.005, and p < 0.001, respectively). Nitric oxide levels were significantly reduced in the patient group (p < 0.001). There was a significant difference between groups in terms of low-density lipoprotein (LDL) but not of high-density lipoprotein (HDL) and triglyceride levels. A significant correlation was observed between CIMT and serum LDL, HDL, homocysteine, nitric oxide levels, and urinary albumin excretion. Microalbuminuria was significantly correlated with serum homocysteine levels (p=0.03) but not with nitric oxide. CONCLUSION: Independent of elevated blood pressure, subclinical atherosclerosis and endothelial dysfunction exist in normotensive patients with GDM. Further studies with a large number of participants are required to clarify these data.

Synthesis of silver and silver/gold anisotropic nanostructures for surface enhanced Raman spectroscopy applications.

We are reporting the one pot chemical reduction synthesis of isotropic spherical silver nanoparticles of size around 4-8 nm and some anisotropic nanostructures of silver and silver-gold systems such as silver nanoprisms of size around 60-80 nm, silver/gold prismatic core/shell nanostructures of size around 30-50 nm and alloy like silver-gold prismatic nanoframes of size around 40-60 nm and investigated their plasmonic properties for the surface enhanced Raman spectroscopy (SERS) applications. Morphology and shape dependent plasmonic properties of these nanostructures were characterized by using high resolution transmission electron microscopy (HRTEM) and UV-Visible spectroscopy techniques respectively. The surface enhanced Raman spectroscopy (SERS) properties of all the fabricated nanostructures were investigated on Methylene Blue (MB) molecule. A gradual improvement in the SERS effect was observed with respect to the change of morphology from spherical to nanoframes and the order of SERS effect was found to be nanoframes > core/shell prismatic nanostructures > nanoprisms > spherical nanoparticles. Our investigation revealed that the phenomenon of the improved SERS effect of anisotropic silver and silver-gold nanostructures is primarily attributed to their prismatic geometrical configurations.

Chromosome heteromorphisms are more frequent in couples with recurrent abortions.

Chromosomal heteromorphism is considered a variant of a normal karyotype, but it is more frequent in couples with repeated miscarriages. We investigated chromosomal heteromorphism in couples with repeated miscarriages in comparison with a control group. A total of 455 couples who applied to our genetic diagnosis laboratory in Diyarbakir, Turkey, were evaluated for chromosome heteromorphisms; 221 of these couples (the study group) had recurrent abortions and 234 of them (the control group) had no history of abortions and had at least one living child. The patient group of couples with recurrent abortions were found to have a significantly higher rate of chromosome heteromorphism (8.4%) in comparison with the control group (4.9%). When the patients were evaluated according to gender, males had a significantly higher rate of chromosome heteromorphism (11.3%) than females (5.4%). We conclude that since couples with recurrent abortion and males have higher rate of chromosome heteromorphism, cases of heteromorphism should not be disregarded in the etiological investigation of recurrent abortions. Further research should be done to investigate the phenotypic effects of chromosome heteromorphism.