Controlling the Crystallographic Orientation of Graphite Electrodes for Fast-Charging Li-Ion Batteries.

In this study, we report a new design paradigm for an electrode preparation method that drastically improves the fast-charging capabilities of a graphite (Gt) anode by controlling the crystallographic orientation. The crystallographic orientation of the Gt electrode is achieved under a dynamic magnetic field using commercially available neodymium magnets. When the slurry of the Gt electrode is tape casted using the conventional method with no magnetic field, the crystallographic orientation is dominated with (002) planes along with other random planes. However, once the slurry of the Gt electrode is casted and dried under a magnetic field, the Gt particles tend to orient themselves along the (100), (101), and (110) planes which are all aligned vertically to the current collector. This striking difference allows the oriented Gt electrode to reach 80% state of the charge in only 50 min at 1C charge rate, whereas the randomly distributed Gt electrode reaches 80% state of the charge in 138 min at 1C charge rate using a constant current-constant voltage charging protocol. The outstanding electrochemical performance of the oriented Gt electrodes was characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, electrochemical cycling, and electrochemical impedance spectroscopy techniques.

A systematic study to understand the effects of particle size distribution of magnetic fingerprint powders on surfaces with various porosities.

This study intends to design magnetite (Fe3 O4 )-based magnetic fingerprint powders with different particle size distributions. It also investigates the influence of particle size distribution on the visualization of latent fingermarks with as little background staining as possible on the surfaces with various porosities in a systematic way. Two strategies were used to prepare the magnetic fingerprint formulations for this study: milling of coarse magnetite particles for different durations, and mixing of sieved fine particles with different size ranges with coarse particles. Particle size analyses of the prepared magnetic powders, optical microscopy-based roughness analysis of the surfaces and SEM measurements of the visualized fingerprints and representative powders were performed. Mag2 of the formulations prepared through milling and Mag5 and Mag6 of the formulations prepared through sieving and mixing were more successful in the development of latent prints than the rest of the solutions.

Complete chorioamniotic separation and persistence of a yolk sac associated with triploidy.

BACKGROUND: Triploidy is a highly lethal condition, and is thus very rarely observed in live births. It may result in significant medical risk to the pregnant woman. CASE: A 32-year-old multigravid woman presented for prenatal care. Ultrasound examination at 14+3 weeks of gestation revealed a viable fetus with appropriate fetal biometry, but with evidence of chorioamniotic separation (CAS) and persistence of the yolk sac. Two weeks later, repeat ultrasound showed a large multicystic placenta and early fetal symmetrical growth restriction with persistence of CAS and yolk sac, raising the suspicion of fetal aneuploidy. Amniocentesis showed a fetal karyotype of 69,XXX. The histology of the placental tissue was a partial hydatidiform mole. CONCLUSION: Persistence of chorioamniotic separation and yolk sac during the early second trimester cannot be considered a reassuring finding. In such cases, fetal karyotyping should be considered, especially when an additional abnormality is found.

Contexte : La triploïdie est une pathologie grandement mortelle; ainsi, il est très rare d'en constater la présence dans le cadre d'une naissance vivante. Elle peut en venir à constituer un risque médical considérable pour la femme enceinte. Cas : Une femme multigravide de 32 ans a sollicité nos services pour l'obtention de soins prénataux. L'examen échographique mené à 14+3 semaines de gestation a révélé la présence d'un fœtus viable qui présentaient une biométrie fœtale appropriée, tout en indiquant également des signes de séparation chorioamniotique (CAS) et la persistance du sac vitellin. Deux semaines plus tard, la tenue d'un deuxième examen échographique a révélé la présence d'un large placenta multikystique et d'un retard de croissance fœtal symétrique précoce, en plus d'indiquer la persistance de la CAS et du sac vitellin, ce qui nous a menés à soupçonner la présence d'une aneuploïdie fœtale. L'amniocentèse a indiqué la présence d'un caryotype fœtal 69,XXX. L'histologie du tissu placentaire a indiqué qu'il s'agissait d'une môle hydatiforme partielle. Conclusion : La persistance de la séparation chorioamniotique et du sac vitellin aux débuts du deuxième trimestre ne peut être considérée comme étant une constatation rassurante. Dans de tels cas, la tenue d'un caryotypage fœtal devrait être envisagée, particulièrement lorsque la présence d'une autre anomalie est constatée.

Prenatal diagnosis of adrenal neuroblastoma: a case report with a brief review of the literature.

A case of adrenal cystic neuroblastoma detected at 37 weeks of gestation is reported. Postnatal ultrasonographic examination showed slightly increased in size demonstrating marked septations within the cyst. After the tumor was resected, histopathological examinations confirmed the diagnosis. The patient is developing normally at 1 year of age.

Prenatal diagnosis of fetal ovarian cyst: case report and review of the literature.

Foetal ovarian cysts are the most frequently encountered intra-abdominal cystic masses diagnosed prenatally. The aetiology of foetal ovarian cysts is still unknown, but hormonal stimulation is generally considered to be responsible for the disease. The diagnosis is made by the exclusion of other cystic lesions confined to the foetal abdomen. In this article we report antenatally-detected foetal ovarian cyst with a review of the available literature. Antenatal ultrasonography (USG) revealed an abdominal cystic mass 41×33 mm in diameter in a 33-week gestation female foetus. The normal anatomy of other foetal abdominal organs suggested that an ovarian cyst was the most likely diagnosis. In the antenatal follow-up period, the cyst diameter increased with time. After delivery, USG scan confirmed the antenatal findings. Due to abdominal distension and respiratory distress, ovarian cystectomy was performed on the second postnatal day. The histopathological evaluation of the surgical material reported a serous cystadenoma of the ovary with non-malignant properties.

The pro-angiogenic properties of multi-functional bioactive glass composite scaffolds.

The angiogenic properties of micron-sized (m-BG) and nano-sized (n-BG) bioactive glass (BG) filled poly(D,L lactide) (PDLLA) composites were investigated. On the basis of cell culture work investigating the secretion of vascular endothelial growth factor (VEGF) by human fibroblasts in contact with composite films (0, 5, 10, 20 wt %), porous 3D composite scaffolds, optimised with respect to the BG filler content capable of inducing angiogenic response, were produced. The in vivo vascularisation of the scaffolds was studied in a rat animal model and quantified using stereological analyses. The prepared scaffolds had high porosities (81-93%), permeability (k = 5.4-8.6 x 10⁻9 m²) and compressive strength values (0.4-1.6 MPa) all in the range of trabecular bone. On composite films containing 20 wt % m-BG or n-BG, human fibroblasts produced 5 times higher VEGF than on pure PDLLA films. After 8 weeks of implantation, m-BG and n-BG containing scaffolds were well-infiltrated with newly formed tissue and demonstrated higher vascularisation and percentage blood vessel to tissue (11.6-15.1%) than PDLLA scaffolds (8.5%). This work thus shows potential for the regeneration of hard-soft tissue defects and increased bone formation arising from enhanced vascularisation of the construct.

SERS not to be taken for granted in the presence of oxygen.

Oxidation of the Ag nanoparticle surface has a dramatic effect on the adsorption, orientation, and SERS detection limit of nitroaromatic molecules in aqueous solutions. Ultrasensitive SERS detection of p-nitrophenol can be achieved when oxidation of surface-immobilized Ag nanoparticles is inhibited by replacing the oxygen dissolved in water with argon gas. The presence of silver oxide at the nanoparticle surface hinders charge transfer between the aromatic ring and the underlying Ag metal surface and drastically decreases the overall detection sensitivity.

Substrates with discretely immobilized silver nanoparticles for ultrasensitive detection of anions in water using surface-enhanced Raman scattering.

Positively charged silver nanoparticles, Ag [+], obtained by UV-assisted reduction of silver nitrate using branched poly(ethyleneimine) (BPEI) and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) solutions as reducing agents, were immobilized on glass surfaces to produce substrates active in surface-enhanced Raman scattering (SERS). Negatively charged silver nanoparticles, Ag [-], synthesized via a modified citrate reduction method, were also investigated for comparison. At a sparse surface coverage of 30 nanoparticles/microm(2), substrates with immobilized Ag [+] showed increasing SERS sensitivity to a variety of anions in water in the order SO(4)(2-) < CN(-) < SCN(-) approximately ClO(4)(-), with corresponding binding constants of 10(5), 3.3 x 10(5), and 10(7) (for both SCN- and ClO(4)(-)) M(-1), respectively. This order followed the Hofmeister series of anion binding in water. Significantly, substrates with Ag [+] allowed limit of detection values of 8.0 x 10(-8) M (8 ppb) and 2.7 x 10(-7) M (7 ppb) for environmentally relevant perchlorate (ClO(4)(-)) and cyanide (CN(-)) anions, respectively. In contrast, substrates with immobilized Ag [-], even upon subsequent modification by a monolayer of BPEI for positive surface charge of the nanoparticles, showed a drastically lower sensitivity to these anions. The high sensitivity of substrates with Ag [+] for anion detection can be attributed to the presence of two types of functional groups, amino and amide, on the nanoparticle surface resulting from UV-assisted fragmentation of BPEI chains. Both amino and amide provide strong binding of anions with Ag [+] nanoparticles due to the synergistic effect through a combination of electrostatic, hydrogen bonding, and dispersive interactions.

Synthesis of positively charged silver nanoparticles via photoreduction of AgNO3 in branched polyethyleneimine/HEPES solutions.

Branched polyethyleneimine (BPEI) and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) were used collaboratively to reduce silver nitrate under UV irradiation for the synthesis of positively charged silver nanoparticles. The effects of molar ratio of the ingredients and the molecular weight of BPEI on the particle size and distribution were investigated. The mechanism for the reduction of Ag+ ions in the BPEI/HEPES mixtures entails oxidative cleavage of BPEI chains that results in the formation of positively charged BPEI fragments enriched with amide groups as well as in the production of formaldehyde, which serves as a reducing agent for Ag+ ions. The resultant silver nanoparticles are positively charged due to protonation of surface amino groups. Importantly, these positively charged Ag nanoparticles demonstrate superior SERS activity over negatively charged citrate reduced Ag nanoparticles for the detection of thiocyanate and perchlorate ions; therefore, they are promising candidates for sensing and detection of a variety of negatively charged analytes in aqueous solutions using surface-enhanced Raman spectroscopy (SERS).

Control of specific attachment of proteins by adsorption of polymer layers.

This study concerns the design of protein-resistant polymer adsorbed layers for the control of surface binding of biospecific recognition entities. Polymer surface layers were prepared using the adsorption of poly(allylamine hydrochloride) (PAH), poly(l-lysine) (PL), and branched and linear polyethyleneimine (PEI) and further modified by the covalent attachment of biotin for specific avidin attachment. The adsorption of PAH, PL, and PEI on silicon substrates was studied as a function of pH and ionic strength using ellipsometry. Average dry layer thicknesses of approximately 10, approximately 5, approximately 9, and approximately 3 A (+/-1 A) were obtained when polymer adsorption occurred from solutions at pH 9.5 that contained 0.5 M NaCl for PAH, PL, branched PEI, and linear PEI, respectively. These polymers showed significant differences in their efficiency to suppress nonspecific avidin adsorption. At low ionic strength, avidin adsorption occurred on all polymer-coated surfaces at basic pH values, despite the same positive electrostatic charge for protein globules and the surface. Though the net electrostatic repulsion between avidin molecules and branched PEI was efficiently screened in a protein solution of pH 7 and 0.15 M NaCl, branched-PEI coatings of high molecular weight were unique in their ability to provide avidin-resistant surfaces as a result of steric hindrance from the branched architecture of adsorbed polymer chains. All polymers studied were effective in suppressing avidin adsorption at pH 3 as a result of protonation of the avidin surface functional groups at this pH. Branched-PEI-coated surfaces were also effective for the suppression of smaller positively charged proteins such as lysozyme and ribonuclease A at pH 7 and 0.15 M NaCl. They were also resistant to the adsorption of negatively charged proteins such as BSA and fibrinogen at pH 7 and 0.75 M NaCl. Furthermore, by using PEI-modified protein-repellent surfaces, selective binding of avidin was achieved to surface-bound silver nanoparticles, which should provide a promising application for the label-free detection of biological species using surface-enhanced Raman scattering (SERS).

The recycling of the coal fly ash in glass production.

The recycling of fly ash obtained from the combustion of coal in thermal power plant has been studied. Coal fly ash was vitrified by melting at 1773 K for 5 hours without any additives. The properties of glasses produced from coal fly ash were investigated by means of Differential Thermal Analysis (DTA), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) techniques. DTA study indicated that there was only one endothermic peak at 1003 K corresponding to the glass transition temperature. XRD analysis showed the amorphous state of the glass sample produced from coal fly ash. SEM investigations revealed that the coal fly ash based glass sample had smooth surface. The mechanical, physical and chemical properties of the glass sample were also determined. Recycling of coal fly ash by using vitrification technique resulted to a glass material that had good mechanical, physical and chemical properties. Toxicity characteristic leaching procedure (TCLP) results showed that the heavy metals of Pb, Cr, Zn and Mn were successfully immobilized into the glass. It can be said that glass sample obtained by the recycling of coal fly ash can be taken as a non-hazardous material. Overall, results indicated that the vitrification technique is an effective way for the stabilization and recycling of coal fly ash.