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Elderly patients have been consistently shown to receive suboptimal therapy for cancers of the head and neck. This study was performed to determine the peri-operative outcomes of these patients and compare them with those of younger patients.
In this retrospective analysis, 115 patients aged 70 years or more undergoing major surgery for head and neck cancers were matched with 115 patients aged 50–60 years, and univariate analysis was performed.
Elderly patients had a reduced performance status (p < 0.001) and more co-morbid illnesses (p = 0.007), but a comparable intra-operative course. They had a longer median hospital stay (p = 0.016), longer intensive care unit stay (p = 0.04), longer median tracheostomy dependence (p = 0.04) and were more often discharged with feeding tubes (p < 0.001). They also had a higher incidence of post-operative non-fatal cardiac events (p = 0.045).
Elderly patients with good performance status should receive curative-intent surgery. Although hospital stay and tube dependence are longer, morbidity and mortality are comparable with younger patients.
Socioeconomic difficulties affect the cognitive and emotional development of children. However, the focus of prior studies has largely been on poverty and material hardship. This study expands on the existing literature by examining the impact of familial transient financial difficulties during infancy on long-term cognitive and behavioral outcomes.
The National Longitudinal Surveys of Youth (79) were used to assess the association between a transient drop in family income by 50% or more (called transient income decline or TID) during the first 3 years of life and later-life Peabody Individual Achievement Math and Reading scores and behavior problem index (BPI) scores (N = 8272–17 348; median assessment age = 9 years). A subsample of matched siblings (N = 2049–4238) was examined to tease out maternal and intra-familial effects.
Exposure to TID predicted increased total and externalizing BPI scores (std. coefficients of 0.10 and 0.09, respectively, p < 0.01) in the overall sample. Among matched siblings, exposure to TID predicted increased total, externalizing, and internalizing BPI scores (std. coefficients of 0.27, 0.25, and 0.23, respectively, p < 0.01).
Familial transient financial difficulties can have long-lasting behavioral effects for infants. The study identifies an early risk factor and at-risk children, thus providing insight into developing early intervention measures for infants to avoid long-term behavioral problems.
An international Low Frequency VLBI Network (LFVN) has been organized for observations at 327 MHz and 1665 MHz frequencies with MARK-II and S2 recording terminals. Data on the interplanetary medium and spike-like solar bursts were obtained in first preliminary experiments.
This paper presents a detailed analysis of 80 type III radio bursts, two noise storms and 10 type II radio bursts observed in the 30-80 MHz range with the new radio spectrograph (Madurai Solar Radio Spectrograph) when it was operated on a daily basis during the periods December 1997 — April 1998 and August 1998. Results from statistical analysis of type III bursts are in agreement with earlier results. Employing a technique of separating the background continuum of noise storms show that the continuum is produced by electron accumulated from the preceding bursts. Also it is seen that the number of occurrences of type I bursts is maximum during the maximum of the background continuum. Comparison of records of type II bursts from MSRS with other spectrographs (Culgoora & Hiraiso) for the same bursts indicate that the sensitivity of the MSRS at low frequencies is much better than the other spectrographs.
The focused ion beam (FIB) has the necessary precision, spatial resolution and control over ion delivery for potential nano-scale doping of nanostructures such as semiconductor quantum dots (QDs). The ion current density in a FIB is 0.1-10 A/cm2, which is at least three orders of magnitude higher than that in a commercial broad beam ion implanter. Therefore an understanding of FIB implantation damage and recovery is of substantial interest. In this work we employ Raman probes of wavelengths 514 nm and 405 nm for quantifying ion implantation damage—both before and after annealing—in 30 kV Si2+, Ge2+ and Ga+ implants (fluences: 1x1012-5x1015 ions/cm2) into Si(100), for the purpose of understanding the effect of ion species on damage recovery.
An investigation was carried out to quantify and characterize the corrosion behavior of
AZ61A magnesium alloy joints. Extruded 6-mm-thick Mg alloy plates of AZ61A grade were
butt-welded using a solid-state, environmentally cleaner welding process, the friction
stir welding process. The weld specimens underwent immersion, salt spray, pitting and
galvanic corrosion tests in order to quantify and characterize the corrosion rates of the
welds with the influence of different pH values, chloride ion concentrations and the
corrosion time. The corrosion rates, microstructure, scanning electron microscopy and
X-ray diffraction analysis concluded the optimum parameters for the usage of the magnesium
alloy welds for the best service applications.
The effect of sulfur and hydrogen plasma treatment on the Schottky barrier and photoluminescence (PL) properties of p-InP is reported. Both the treatments increase the barrier height of Au/p-InP diodes and band to band PL. This is explained as being due to a shift in the surface fermi level position towards the P vacancy related pinning level in the top half of the band gap. The H+ treatment passivates the shallow and deep levels as observed from the C-V depth profile and PL respectively.
During a routine survey, the scalloped hammerhead shark, Sphyrna lewini was caught from Nagapattinam coastal waters, south-east coast of India. It is the second time this species has occurred after a long period along the Indian coast, and this substantiates the possibility of its entry from another place.
The properties of turbulent mixing in a Richtmyer–Meshkov (RM) unstable fluid layer are studied under the impact of a single shock followed by a reshock wave using simultaneous velocity–density measurements to provide new insights into the physics of RM mixing. The experiments were conducted on a varicose fluid layer (heavy fluid) interposed in air (light fluid) inside a horizontal shock tube at an incident Mach number of 1.21 and a reflected reshock Mach number of 1.14. The light–heavy–light fluid layer is observed to develop a nonlinear growth pattern, with no transition to turbulence upon impact by a single shock (up to ). However, upon reshock, enhanced mixing between the heavy and light fluids along with a transition to a turbulent state characterized by the generation of significant turbulent velocity fluctuations () is observed. The streamwise and spanwise root-mean-squared velocity fluctuation statistics show similar trends across the fluid layer after reshock, with no observable preference for the direction of the shock wave motion. The measured streamwise mass flux () shows opposing signs on either side of the density peak within the fluid layer, consistent with the turbulent material transport being driven along the direction of the density gradient. Measurements of three of the six independent components of the general Reynolds stress tensor () show that the self-correlation terms and are similar in magnitude across much of the fluid layer, and much larger than the cross-correlation term . Most importantly, the Reynolds stresses () are dominated by the mean density, cross-velocity product term (), with the mass flux product and triple correlation terms being negligibly smaller in comparison. A lack of homogeneous mixing (and, possibly, a long-term imprint of the initial conditions) is observed in the spanwise turbulent mass flux measurements, with important implications for the simulation and modelling of RM mixing flows.
Bis(diglycidyl)ether of bisphenol-A-aniline (BP-AN) based second-order nonlinear optical (NLO) polymers containing triene chromophores have been developed through post-polymer functionalization reactions. One-pot aldol condensation reaction of dicyanomethylidene functionalized verbenone as well as isophorone compounds with aldehyde functionalized BP-AN polymer enabled the introduction of various chromophore moieties with high degree of functionalization. These polymers were studied using various structural (1H NMR, FTIR), linear (UV-Vis) and NLO characterization techniques. A d33 value of ca. 139 pm/V at 1.064 µm was determined for a representative polymer containing verbenone unit. We have observed fast photo-bleaching in these polymers. Detailed studies on the photophysical properties of this class of materials have been carried out using various analytical techniques, the structure-properties relationship and photo-bleaching mechanisms will be presented.
Functionalized aromatic-bis(benzothiazoles) have been synthesized by our group and have shown promise as conductive n-dopable polymers and oligomers. When reduced (n-doped) these materials typically exhibit conductivity on the order of tens of S/cm. Here we examine the material properties of this family of derivatized, conductive aromatic-bis(benzothiazoles). A variety of synthetic approaches have been examined to produce these polymers and oligomers, and will be discussed. Material characterization has been accomplished by spectro-electrochemistry, nuclear magnetic resonance (NMR), electron spin resonance (ESR), Fourier Transform Infrared (FTIR) spectroscopy, and direct current (DC) conductivity.
Nickel monosilicide (NiSi) is a leading contender to replace the currently used class of silicides for contacts to the source, drain and gate regions in Complimentary Metal-Oxide- Semiconductor (CMOS) circuits. In this work, the effect of substrate hydrogenation by a hydrogen plasma treatment prior to nickel deposition and silicidation was studied. The sheet resistance of the silicide film shows a significant decrease under hydrogenation of the Si substrate prior to Ni evaporation/anneal for projected silicidation temperatures below 600°C. Correspondingly, the Si region near the interface is decorated with defects. At higher silicidation temperatures, the sheet resistance rises along with greater in-diffusion of Ni into the hydrogenated Si samples. Secondary Ion Mass Spectrometry, Transmission Electron Microscopy and Hall effect measurements are used to characterize the samples.
The sidewalls of etched Si lines will be the carrier channel surfaces in FinFET devices. These surfaces must be as smooth as possible for optimal device performance. Thus, the ability to quantitatively measure sidewall roughness is essential to process development. A methodology to quantitatively measure Fin sidewall roughness by AFM is presented. The samples were prepared for measurement by cleaving along the length of the Fins or dense-line test structures and by FIB polishing to bring the edge of the sample close to the sidewall of the etched feature. The cleaved and FIB-polished sample was mounted 17 degrees shy of normal. This exposes the sidewall on the top surface while preventing shadowing of the lower part of the sidewall due to contact between the side of the probe support and the cleaved or polished edge. Quantitative AFM measurements taken by this method show meaningful differences in the sidewall roughness for samples that have seen different sidewall smoothing treatments. The average observed rms roughness values for various surface-smoothing treatments range from 0.8 to 1.8 Å for a 50 nm square area.
The effect of hydrogenation on the photoluminescence (PL) of InP : Mg, InP : Zn and undoped n-InP is presented. An increase in the near band edge pl intensity due to passivation of non-radiative centers was observed in all the samples. A donor - acceptor pair transition was observed before hydrogenation in the InP : Mg sample and after hydrogenation in the InP : Zn sample due to the acceptor deactivation. In n-InP the enhancement of donor bound exciton after hydrogenation points to the absence of donor passivation.
We study the stability range for a coherent interface between Ge quantum dots and an epitaxial Si shell. The critical radius at which coherency is lost is evaluated as a function of Si shell thickness and Ge nanocrystallite radius by comparing the energy of the system in the coherent and incoherent state. We find that the system is coherent up to a Ge nanocrystallite radius of about 100 Å, irrespective of the Si shell thickness. Nanocrystallites of radii larger than 270 Å lose coherency by the generation of perfect dislocation loops. In nanocrystallites of intermediate radii ( between 100 Å and 270 Å), the coherency is lost by the introduction of partial dislocation loops enclosing a stacking fault. As the shell thickness decreases, the critical radius increases.
One-pot post-polymerization modification reactions such as azo-coupling and tricyanovinylation reactions were employed to synthesize a series of polymers containing different nonlinear optical (NLO) chromophoric as well as ionic functionalities. We have extended and established the versatility of our earlier reported post-modification strategy to incorporate various heteroaromatic chromophores as well as ionic functionalities in the polymers, at the final stage of synthesis. The correlation between different heteroaromatic chromophore structures and the NLO properties of the polymers was extensively studied. Polymers containing heteroaromatic chromophores exhibit improved temporal stability and enhanced NLO activity. Polymers with ionic chromophores were employed to fabricate NLO active ultra-thin films using electrostatic selfassembling (ESA) technique. Attempts were also made to synthesize second order NLO active polydiacetylene derivatives using post azo-coupling reaction.
We have utilized “in situ” X-ray Absorption Fine Structure Spectroscopy to investigate the structure and composition of thin oxide films of nickel and iron that have been prepared by electrodeposition on a graphite substrate from aqueous solutions. The films are generally disordered. Structural information has been obtained from the analysis of the data. We also present initial findings on the local structure of heavy metal ions, e.g. Sr and Ce, incorporated into the electrodeposited nickel oxide films. Our results are of importance in a number of technological applications, among them, batteries, fuel cells, electrochromic and ferroelectric materials, corrosion protection, as well as environmental speciation and remediation.