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Previous genetic association studies have failed to identify loci robustly associated with sepsis, and there have been no published genetic association studies or polygenic risk score analyses of patients with septic shock, despite evidence suggesting genetic factors may be involved. We systematically collected genotype and clinical outcome data in the context of a randomized controlled trial from patients with septic shock to enrich the presence of disease-associated genetic variants. We performed genomewide association studies of susceptibility and mortality in septic shock using 493 patients with septic shock and 2442 population controls, and polygenic risk score analysis to assess genetic overlap between septic shock risk/mortality with clinically relevant traits. One variant, rs9489328, located in AL589740.1 noncoding RNA, was significantly associated with septic shock (p = 1.05 × 10–10); however, it is likely a false-positive. We were unable to replicate variants previously reported to be associated (p < 1.00 × 10–6 in previous scans) with susceptibility to and mortality from sepsis. Polygenic risk scores for hematocrit and granulocyte count were negatively associated with 28-day mortality (p = 3.04 × 10–3; p = 2.29 × 10–3), and scores for C-reactive protein levels were positively associated with susceptibility to septic shock (p = 1.44 × 10–3). Results suggest that common variants of large effect do not influence septic shock susceptibility, mortality and resolution; however, genetic predispositions to clinically relevant traits are significantly associated with increased susceptibility and mortality in septic individuals.
Pharyngocutaneous fistulae are dreaded complications following total laryngectomy. This paper presents our experience using 3–5 ml gastrografin to detect pharyngeal leaks following total laryngectomy, and compares post-operative videofluoroscopy with clinical follow-up findings in the detection of pharyngocutaneous fistulae.
A retrospective case–control study was conducted of total laryngectomy patients. The control group (n = 85) was assessed clinically for development of pharyngocutaneous fistulae, while the study group (n = 52) underwent small-volume (3–5 ml) post-operative gastrografin videofluoroscopy.
In the control group, 24 of 85 patients (28 per cent) developed pharyngocutaneous fistulae, with 6 requiring surgical correction. In the study group, 24 of 52 patients (46 per cent) had videofluoroscopy-detected pharyngeal leaks; 4 patients (8 per cent) developed pharyngocutaneous fistulae, but all cases resolved following non-surgical management. Patients who underwent videofluoroscopy had a significantly lower risk of developing pharyngocutaneous fistulae; sensitivity and specificity in the detection of pharyngocutaneous fistulae were 58 per cent and 100 per cent respectively.
Small-volume gastrografin videofluoroscopy reliably identified small pharyngeal leaks. Routine use in total laryngectomy combined with withholding feeds in cases of early leaks may prevent the development of pharyngocutaneous fistulae.
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.
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.
Cerebrospinal fluid rhinorrhoea is the abnormal leakage of cerebrospinal fluid into the nasal cavity. The posterior wall of the frontal sinus can be the site of such leakage. Traditionally, these leaks were repaired via external osteoplastic or neurosurgical approaches. Despite advances in instrumentation, it is difficult to manage superiorly or laterally placed defects endoscopically. We present a new technique of endoscopic repair of frontal sinus posterior wall defects, via access holes drilled in the anterior wall of the frontal sinus.
Preliminary study involving patients presenting with frontal sinus cerebrospinal fluid leaks, with defects in the frontal sinus posterior wall, between 2006 and 2010.
Patients were treated in a tertiary referral centre for nose and sinus diseases. Patient records were reviewed and analysed.
Nine patients underwent external frontal sinusotomy under endoscopic vision. Repair was successful in all cases, with no complications. Follow up ranged from three months to three years.
External frontal sinusotomy and endoscopic repair is a simple, precise and cosmetically acceptable alternative to osteoplastic and major neurosurgical techniques for management of frontal sinus posterior wall defects. This new, previously undescribed technique enables otolaryngologists to play a role in managing such defects.
An important metallurgical difficulty in arc welding of high-strength aluminum alloys is
formation of solidification cracking. In this work, an attempt is made to reduce the
solidification cracking in welding of aluminum alloys through vibratory treatment. The
material used for the investigation is AA2014 aluminum alloy, which is highly prone to
solidification cracking. Vibratory treatment was carried out in the frequency range of 100
Hz to 3700 Hz. Weldments made with and without vibratory treatment were compared using
weld cracking tests and other characterization tests such as microstructural analysis. The
test results show that by applying vibratory treatment, solidification cracking can be
largely controlled in arc welding.
To present our experience in managing cerebrospinal fluid rhinorrhoea using the cartilage inlay (underlay) technique to repair skull base defects larger than 4 mm.
Retrospective study involving patients presenting with cerebrospinal fluid rhinorrhoea between 1994 and 2008.
Patients were treated in a tertiary referral centre for nose and sinus diseases. Patients' medical records were reviewed and analysed.
A total of 62 patients were operated upon using a cartilage inlay technique to repair bony skull base defects ranging in size from 4 to 20 mm (widest diameter). Of these 62 patients, 16 constituted revisions of earlier procedures undertaken elsewhere. The success rate of the technique was 100 per cent. Patient follow up ranged from six months to 16 years, with a median follow up of 15 months. Three patients had minor post-operative sinus infections; no serious complications were encountered.
Extradural cartilage inlay appears to be an effective technique in the management of cerebrospinal fluid rhinorrhoea, especially for large defects and revision procedures. To our knowledge, the described patients represent the largest reported series of cerebrospinal fluid rhinorrhoea cases managed using the cartilage inlay technique. We believe that the crucial factors in our high success rate for cerebrospinal fluid fistula repair are: precise identification of the bony defect; meticulous preparation of the graft bed; careful elevation of the dura; judicious use of just enough graft tissue; and adequate graft support.
To evaluate the type of aerobic bacteria commonly isolated from peritonsillar abscesses.
A retrospective study involving 60 patients presenting with peritonsillar abscess treated between 2003 and 2006.
The patients were treated in a tertiary care, teaching hospital. The records of the patients were reviewed and analysed.
Gram-positive organisms were commonly isolated from the abscesses. However, an increasing trend towards Gram-negative bacterial isolates was noted. The antibiogram showed changing patterns of sensitivity, with a resistance to penicillin.
There is an increasing incidence of Gram-negative aerobic bacteria causing peritonsillar abscess. Appropriate antibiotics for Gram-negative bacteria should be included in the regimen if such bacteria are isolated in culture and sensitivity studies.
Empirical antibiotics with Gram-negative cover will be appropriate as adjunctive therapy.
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.
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.
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 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.
While crystallite-rotation experiments of the type pioneered by Gleiter and his co-workers have provided a great deal of information about the variation of grain boundary energy with crystal misorientation, certain aspects of the experiments still remain puzzling. Notably, crystal rotation rates do not follow the form predicted by consideration of the Read-Shockley equation; and Chan and Balluffi have shown that in some cases certain crystallites are able to escape from the energy cusps that trap others . In this paper we re-examine the crystallite rotation mechanism and rotation rates from the perspective of the interactions of grain boundary dislocations with the free surfaces that terminate the grain boundary.
Laboratory studies have been made on molecules of astrophysical interest such as AlO, CO, CrO, SiS, NH+ and OH. Vibrational and rotational constants have been determined more accurately in the various electronic states.
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