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Three-dimensional (3D) printing technology is a promising method for bone tissue engineering applications. For enhanced bone regeneration, it is important to have printable ink materials with appealing properties such as construct interconnectivity, mechanical strength, controlled degradation rates, and the presence of bioactive materials. In this respect, we develop a composite ink composed of polycaprolactone (PCL), poly(D,L-lactide-co-glycolide) (PLGA), and hydroxyapatite particles (HAps) and 3D print it into porous constructs. In vitro study revealed that composite constructs had higher mechanical properties, surface roughness, quicker degradation profile, and cellular behaviors compared to PCL counterparts. Furthermore, in vivo results showed that 3D-printed composite constructs had a positive influence on bone regeneration due to the presence of newly formed mineralized bone tissue and blood vessel formation. Therefore, 3D printable ink made of PCL/PLGA/HAp can be a highly useful material for 3D printing of bone tissue constructs.
Declining pulse production has caused wide concern in recent years. A field experiment was conducted to investigate effects of balance fertilizers based on soil test values and targeted yield equations on soil biological activities, soil quality, nutrient acquisition and grain yield of lentil. Treatments included the use of farmyard manure (FYM), bio-inoculants and inorganic fertilizers at different rates and combinations. The results revealed significant improvement in nodulation, microbial counts, microbial biomass carbon (MBC), soil respiration, soil enzymes and soil organic carbon (SOC) with integrated approaches (i.e. fertilizer plus FYM or bio-inoculants); these improvements led to achievement of the specific target yield of 1.50 t/ha. Although the highest yield was achieved with fertilizers applied for a target yield of 2.0 t/ha, there was significant decline in nodulation, microbial counts, MBC, soil respiration, soil enzymes, SOC and soil quality. Correlation between soil quality index (SQI) and grain yield suggested a significant influence of balanced fertilization based on soil tests and target yield. Principal component analysis revealed the average contribution of soil quality indicators towards SQI was in descending order of SOC > acid phosphatase activity > total culturable fungi > available phosphorus > BMC, which are crucial for sustainable lentil production in alluvial soils.
A new species, Gentiana arunii D.Maity, S.K.Dey, J.Ghosh & Midday, from alpine pasture in Sikkim Himalaya is described and illustrated, and placed in Gentiana section Chondrophyllae Bunge. The new species is compared morphologically with two related taxa, Gentiana glabriuscula T.N.Ho and Gentiana pluviarum W.W.Sm. subsp. subtilis (Harry Sm.) T.N.Ho.
The visceralizing potential of apparently dermotropic Leishmania donovani in Sri Lanka (L. donovani-SL) was investigated through long-term follow-up of cutaneous leishmaniasis (CL) patients and in vivo and in vitro experimental infection models. CL patients (n = 250) treated effectively with intra-lesional antimony therapy were followed-up six monthly for 4 years. There was no clinical evidence of visceralization of infection (VL) during this period. Infection of BALB/c mice with L. donovani-SL (test) through intra-dermal route led to the development of cutaneous lesions at the site of inoculation with no signs of systemic dissemination, in contrast to the observations made in animals similarly infected with a visceralizing strain of L. donovani-1S (control). Cytokine (IL-10, IFN-γ) release patterns of splenocytes and lymph node cell cultures derived from mice primed with experimental infections (with either test or control parasites) revealed significantly high IFN-γ response associated with test mice with CL, while prominent IL-10 levels were observed in association with control mice with VL. Furthermore, diminished infection efficiency, intracellular growth and survival of L. donovani-SL parasites compared with L. donovani-1S were evident through in vitro macrophage infection experiments. These studies confirm, for the first time, the essential dermotropic nature of L. donovani-SL suggesting natural attenuation of virulence of local parasite strains.
Blazar OJ287 exhibits large thermal flares at least twice every 12 years. The times of these flares have been predicted successfully using the model of a quasi-Keplerian eccentric black hole binary where the secondary impacts the accretion disk of the primary, creating the thermal flares. New measurements of the historical light curve have been combined with the observations of the 2015 November/December flare to identify the impact record since year 1886, and to constrain the orbit of the binary. The orbital solution shows that the binary period, now 12.062 years, is decreasing at the rate of 36 days per century. This corresponds to an energy loss to gravitational waves that is 6.5 ± 4 % less than the rate predicted by the standard quadrupolar gravitational wave (GW) emission. We show that the difference is due to higher order gravitational radiation reaction terms that include the dominant order tail contributions.
A new species of Kuepferia (Gentianaceae), K. pringlei D.Maity & Sentu K.Dey from north Sikkim, Eastern Himalaya, is described and illustrated. Details of habitat, phenology and conservation status are given, and it is compared to related species. This previously undescribed species is most similar to, but distinct from, Kuepferia leucantha (Harry Sm. ex T.N.Ho & S.W.Liu) Adr.Favre, known from Bhutan and China.
A total of 7185 faecal specimens collected from infants and children with gastroenteritis in seven different regions of Japan during 1995–2009 were examined for adenovirus by polymerase chain reaction. Adenovirus was detected in 568 (7·9%) patients. The adenovirus activity peak was in winter and spring seasons (December–March) during the study period in the Japanese paediatric population. During the last 15 years, adenovirus 41 was the most predominant strain in Japan.
A novel methodology using a combination of ion scattering, x-ray reflectivity (SXR), and small angle neutron scattering was used to characterize the structure and properties of a hydrogen silsesquioxane (HSQ) based porous low-k dielectric films after varying process conditions. The dielectric constant and the remaining Si-H fraction (degree of cure) of the samples were varied from 1.5 to 2.2 and from 30 % to 52 %, respectively, by controlling the mass ratio of the solvent and the HSQ resin in the initial solutions and the wet ammonia treatment time. We determined the density depth profile, average mass density, wall density, porosity, average pore size, average wall thickness, pore connectivity and atomic composition. The chemical bond structures were also measured using Fourier transform infrared (FTIR) spectroscopy. The density profile of each porous low-k film was uniform and only two layers were required to fit the experimental SXR data. Higher dielectric constant films show significantly higher wall densities and lower porosities and pore sizes. The measured increases in the wall density with lower Si-H fractions are consistent with the FTIR results.
Low-k dielectric films have been developed using a new silsesquioxane based chemistry that allows both the electrical and mechanical properties to be tuned to specific values. By controlling the composition and film processing conditions of spin-on formulations, dielectric constants in the range 1.5 to 3.0 are obtained with modulus values that range from 1 to 30 GPa. The modulus and dielectric constant are tuned by controlling porosity, which varies from 0 to >60%, and final film composition which varies from HSiO3/2 to SiO4/2. The spin-on formulation includes hydrogen silsesquioxane resin and solvents. Adjusting the ratio of solvents to resin in the spin-on formulation controls porosity. As-spun films are treated with ammonia and moisture to oxidize the resin and form a mechanically self-supporting gel. Solvent removal and further conversion to a more “silica-like” composition occur during thermal curing at temperatures of 400 to 450°C. The final film composition was controlled through both room temperature oxidation and thermal processing. Final film properties are optimized for a balance of electrical, mechanical and thermal properties to meet the specific requirements of a wide range of applications. Processed films exhibit no stress corrosion cracking or delamination upon indentation, with indenter penetration exceeding the film thickness, and followed by exposure to water at room temperature. Films also exhibit high adhesive strength (> 60MPa) and low moisture absorption. Processing conditions, composition and properties of thin are discussed.
Sapovirus, a member of the family Caliciviridae, is one of the major causative agents of viral gastroenteritis affecting all age groups. A total of 3232 faecal specimens collected from infants and children with gastroenteritis in five different regions of Japan during 2003–2009 were examined for sapovirus by reverse transcription–polymerase chain reaction. Sapoviruses were detected in 131 (4·05%) patients with the peak observed mainly in the cold season (November–March) in Japan during 2003–2009. During the last 6 years, sapovirus GI/1 was the predominant strain in Japan followed by GIV, GII/3, GII/6, GII/2, GII/12 and GI, respectively.
Sol-gel processing represents a promising method of fabrication for thin films of electronic ceramics which are useful in a number of packaging and device applications. In this study, the influence of acid and base catalysts on the structure of PbTiO3 gels and films (0.1–1.0 μm) was investigated, for the purpose of inducing and identifying gel structures which were the most suitable as precursors for thin dielectric layer. Continuous, crack-free films, with dielectric strengths in excess of 106 V/cm were developed. Basic solutions gelled rapidly, phase separated, and were probably more crosslinked than acidic gels. Acidic gels seemed more capable of polymeric rearrangement during drying, yielding denser amorphous structures with microcrystalline regions. High-field dielectric constants (1 MV/m ac) in the range K=30–40 and K=160–170, were determined for amorphous and crystalline films, respectively.
Ferroelectric Pb(Zr0.52Ti0.48)O3 or PZT (52/48) thin-films (0.5 μm) were integrated onto Pt passivated Si wafers (3–4 inches) by polymeric solgel processing followed by rapid thermal annealing. Dense and crack-free perovskite microstructures were obtained by densification of the amorphous gel-matrix prior to crystallization. The films exhibited submicron grains (0.2–0.6 μm) with a columnar growth habit. High field measurements on thin-films determined Pr, Psp, and Ec in the ranges of 29–32 μC/cm2. 44–58 μC/cm2, and 50–60 kV/cm, respectively, and ferroelectric switching times below 3 ns.
Sol-gel processing represents a promising method of fabrication for thin films of electronic ceramics which are useful in a number of packaging and device applications. In this study, the influence of acid and base catalysts on the structure of PbTiO3 gels and films (0.1-1.0μm) was investigated, for the purpose of inducing and identifying gel structures which were the most suitable as precursors for thin dielectric layers. Continuous, crack-free films, with dielectric strengths in excess of 106 V/cm were developed. Basic solutions gelled rapidly, phase separated, and were probably more crosslinked than acidic gels. Acidic gels seemed more capable of polymeric rearrangement during drying, yielding denser amorphous structures with microcrystalline regions. High-field dielectric constants (1 MV/m ac) in the range K=30–40, and K=160–170, were determined for amorphous and crystalline films, respectively.
A modification of the standard Sawyer-Tower circuit method of displaying ferroelectric hysteresis allowed the technique to be extended to sinusoidal switching frequencies of 2 MHz. Using this method, probe station measurements of switched remanent polarization were made for two films: excimer-laser-deposited lead zirconate titanate (PZT) and sol-gel PZT. Switched remanent polarization and dielectric constant were measured as a function of frequency between 100 Hz and 2 MHz and as a function of elapsed switching cycles at the 1-MHz rate. Both films showed decreasing switched remanent polarization and dielectric constant with increasing frequencies. This effect is attributed to limitations in domain wall velocity.
High-resolution electron microscopic examination of alkoxide thin-film gels has been employed to study the drying and aging of thin-film Pb(Zr0.45Ti0.55)O2 (OR) 2 as it evolves from the gel to the ferroelectric perovskite product. The initially amorphous film is observed to aggregate to form ordered islands with inter-metal distances close to that of the final structure embedded in a highly disordered matrix. When these aggregates are at the surface they grow and decompose more rapidly to the perovskite product. The progress to a polycrystalline final state is followed and recorded in real time and in time-lapse at high resolution.
The nanostructure evolution of PZT, PT and T thin films has been studied by high-resolution electron microscopy (HREM) supported by other techniques such as thermal analysis, thermal mass spectrometric analysis and X-ray diffraction analysis. The evolution follows a common progression from amorphous film, to the development of condensed regions that develop crystalline order, to the final polycrystalline oxide thin film. If the precursor gel contains lead, the film develops fluctuating surface “blisters” that evolve to an oxide final product as well. Minor structural and compositional differences exist across the final oxide thin film.
In the present work we have studied efficacy of ion beam induced epitaxial crystallization (IBIEC) to recover amorphous layers (300 – 350 nm) produced by MeV Kr ions in Si(100) and studied the associated changes occurring on surface and interface of the recrystallized region. IBIEC experiments were carried out at sample temperatures in the range of 200 − 400°C using 1 MeV N+ ion beam. Rutherford backscattering-Channeling technique showed planar and gradual recovery of the amorphous layer as a function of temperature. Transmission electron microscopy measurements show good crystalline structure of the recovered region at 400°C while at lower temperatures nano-crystalline Si formation embedded in the amorphous structure is evident. The surface topography studied by atomic force microscopy shows development of islands after IBIEC. The rms roughness is around 0.5 nm and average height of the islands is found to be 1.8 nm. The observed epitaxial growth and the surface topographical features have been correlated.