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The decision to routinely leave a nasogastric tube after pancreatoduodenectomy remains controversial. We sought to determine the impact of immediate nasogastric tube removal versus early nasogastric tube removal (24 h) on postoperative outcomes.A retrospective review of our institution's prospective ACS-NSQIP database identified patients that underwent pancreatoduodenectomy from 2015 to 2018. Outcomes were compared among patients with immediate nasogastric tube removal versus early nasogastric tube removal.A total of 365 patients were included in primary analysis (no nasogastric tube, n = 99; nasogastric tube removed24 h, n = 266). Thirty-day mortality and infectious, renal, cardiovascular, and pulmonary morbidity were similar in comparing those with no nasogastric tube versus early nasogastric tube removal on univariable and multivariable analyses (P0.05). Incidence of delayed gastric emptying (11.1 versus 13.2%) was similar between groups. Patients with no nasogastric tube less frequently required nasogastric tube reinsertion (n = 4, 4%) compared to patients with NGT24 h (n = 39, 15%) (OR = 3.83, 95% CI [1.39-10.58]; P = 0.009).Routine gastric decompression can be safely avoided after uneventful pancreaticoduodenectomy.

Distilled water plus 0.1% surfactant suspensions of spores of Aspergillus flavus and Aspergillus parasiticus were exposed to several radiation levels of cobalt-60 gamma rays. Spores of A. flavus isolate M-141 were exposed to radiation levels of approximately 16, 90 and 475 Krads and inoculated onto a sterile rice substrate which was then monitored for aflatoxin production. In this initial trial with A. flavus M-141, aflatoxins B1 and M production on rice increased as radiation dose increased. At the highest dose, this increase was more than 50 times higher than the non-irradiated controls. Spores of an aflatoxin G1-producing A. parasiticus isolate, M-1094, were exposed to 90, 215 and 430 Krads and resulted in increased production of aflatoxins G1, B1, and M. Aflatoxin production by M-1094 was highest at the low and medium dose levels. Irradiation of spores of this isolate with 430 Krads produced no observable spore germination or growth on rice and no detectable aflatoxin after 1 week of incubation at 27 ...

We have determined with infrared spectroscopic ellipsometry how the nature of the interface between a thin polyldimethyl siloxane) (PDMS) coating and its substrate affects the rate of PDMS crosslinking reactions. Reactions between vinyl (-CH=CH 2 ) end groups on PDMS and silyl (SiH) groups in a crosslinker (hydrosilylation) and between SiH groups and silanol (SiOH) groups, during the so-called postcure crosslinking stage, have been probed in situ. The overall consumption of SiH follows first-order reaction kinetics. The first-order reaction coefficient (k 1 ) for the hydrosilylation crosslinking reaction is the same for coatings on three different substrates: native oxide on silicon (SiO 2 /Si), polystyrene (PS), and poly(ethylene terephthalate). For the slower postcure reactions, however, the rate of SiH consumption depends on the substrate. In 2.5-μm PDMS coatings on PS, k 1 is about seven times greater than k 1 in the same coating on SiO 2 /Si. In PDMS coatings on a PDMS substrate, when the effect of the interface is thus minimal, k 1 is 16 times higher than on SiO 2 /Si. The dependence of k 1 on the type of interface is probably the result of the interfacial segregation and complexation of the Pt catalyst for the postcure reactions. We propose that polar surfaces more strongly attract Pt and form complexes that inhibit the postcure reactions.

In a novel application, infrared spectroscopic ellipsometry is used to provide clear evidence for the formation of a covalent bond at a polymer/polymer interface. Specifically, there is evidence for the formation of a Si-O-C bond resulting from a reaction between the silyl (SiH) group of a poly(hydrogen methyl siloxane) crosslinker used in poly(dimethyl siloxane) and the carboxylic acid group of poly(acrylic acid). This covalent bond formation could explain the source of the "lock-up" that is sometimes found between acrylic pressure-sensitive adhesives and a silicone-coated release liner.

We consider reasons why the crosslinking reaction rate in poly(dimethyl siloxane) (PDMS) network coatings might differ from the rate found in the bulk and specifically examine the influence of coating thickness. Infrared spectroscopic ellipsometry (IRSE) is employed as an in situ probe of the reactions between vinyl (–CHCH2) end groups on PDMS and SiH groups in a crosslinker and between unreacted SiH groups and hydroxyl/silanol groups within PDMS coatings, all on silicon substrates. Measurements of the concentrations of SiH groups (using the characteristic vibration at 2160 cm−1) were obtained from coatings between 1 and 27 μm in thickness, over temperatures ranging from 25 to 120 °C. First-order kinetics are exhibited in the consumption of SiH groups. The reaction rate constant is found to decrease with increasing coating thickness. Although there is evidence that the Pt catalyst segregates to the interface with the substrate, this phenomenon does not appear to have an impact on the thickness dependence. The diffusion of water into the silicone might be the rate-limiting step in the reactions, however, and therefore lead to the observed thickness dependence of the reaction rate.

Organosilanes are extensively used to promote the adhesion of surface coatings and adhesives to different substrates, including metals. The surface concentration and spatial distribution of the organosilane on a particular material are important factors in determining its efficiency as an adhesion promoter. The powerful combination of atomic force microscopy (AFM) with X-ray photoelectron spectroscopy (XPS) was adopted to characterise the adsorption of aminopropyltriethoxysilane (APS) on the Al alloy L157-T6. Complementary information on the distribution of the adsorbed APS was obtained using the force–volume (FV) approach in AFM. The combined AFM/XPS study revealed that the coverage and stuctural integrity of the APS film were dependent on the concentration of the silane in solution. Greater coverage and better structural integrity were obtained by adsorbing the APS film from a 3% silane (in methanol) solution than from a 6% solution.

Novel phthalocyanine (Pc) molecules have been designed and synthesized to incorporate a thiol moiety for the formation of monolayer films onto gold-coated optical waveguides via the technique of self-assembly. The thiol moiety is connected to the Pc macrocycle by either a (CH2)11 or (CH2)3 hydrocarbon chain. Both Pc SAMs have been characterized on the metal surface using reflection absorption infrared (RAIR) spectroscopy. The RAIR spectra suggest that the two Pc molecules lie in a different orientation with respect to the gold surface. This behavior can be rationalized with consideration of the different structures (the different alkyl connecting chain lengths and different macrocyclic peripheral side chains) of the two Pc molecules. The fluorescence emission spectrum of each of the Pc SAMs has been obtained by exciting each monolayer along the longitudinal axis of the optical waveguide via laser-induced evanescent wave stimulation. The use of the longer mercaptoalkyl connecting chain appears to inhibit q...

The formation and characterisation of a novel self-assembled monolayer film for gas sensing are reported. The phthalocyanine 1,1′4,4′,8,8′,11,11′,15,15′,18,18′,22,22′-tetradecakishexyl-225,25′-(3,3′-dithiodipropyl)diphthalocyanine, has been synthesised from its hydroxypropyl precursor, via a two-step reaction. The disulfide functionality of the molecule has been used to produce a self-assembled phthalocyanine monolayer on a gold substrate. The phthalocyanine monolayer has been characterised using reflection absorption infrared spectroscopy (RAIRS).

Three mercaptoamines have been lithiated in the presence of various Lewis bases. 2-Mercaptopyrimidine (I), containing a NC(S)NH–(as an amine)/NC(–SH)N–(as a thiol) unit, affords [graphic omitted]S)Li·hmpa]n1. 2-Mercaptothiazoline (II), with a –SC(S)NH–/–SC(–SH)N– unit, gives [graphic omitted]S)Li·tmen]n2. 2-Mercaptobenzimidazole (III), having a –NHC(S)NH–/–NHC(–SH)N– unit, gives, when dilithiated, {[graphic omitted]Li2·3hmpa}n3[hmpa = hexamethylphosphoramide, (Me2N)3PO; tmen = Me2NCH2CH2NMe2]. The solid-state structures of complexes 1–3 were solved by X-ray crystallography. Complex 1 is polymeric (n=∞): each unit contains a (NCS)Li chelate feature with a terminal hmpa molecule on Li, and these units are then associated via intermolecular N→Li co-ordinations using the third (N) heteroatom of the organic anion. Complex 2 is a dimeric (n= 2) S–Li compound with each Li bearing a tmen molecule; dimerisation is achieved by N→Li intermonomer interactions, but the third (ring S) heteroatom is not involved with metal centres. The dilithiated species 3 is also a dimer (n= 2) and each Li is chelated by an (NCS) unit of its organic dianion; the two end-Li atoms of the dimer are each co-ordinated to two terminal hmpa molecules, while the two central Li atoms are linked by two µ-hmpa molecules, which effect dimerisation. The structural diversities displayed by 1–3 have been probed, and thereby in part rationalised, by ab initio(6-31G basis set) and MNDO molecular-orbital calculations on the amine/thiol isomers of I–III, and on their uncomplexed and complexed lithiated derivatives (as monomers). In particular, the optimised structures predict and reproduce the (NCS)Li chelating modes found in 1 and 3 and help to explain why direct S–Li bonding is found in 2.

The hydrophilicity of pedal mucus trails deposited by snails influences the settlement of marine organisms and can potentially influence the trailing and homing mechanisms of terrestrial snails. The composition of pedal mucus deposited as a trail on a solid substrate by the giant African land snail (Achatina marginata) has been probed non-invasively using infrared ellipsometry. The primary chemical groups in the mucus (in its native state) have been identified through their characteristic infrared absorption frequencies. Water vapour sorption in the mucus trails in equilibrium with the atmosphere was measured as a function of the relative humidity (RH). When RH=84%, the mucus contains 53 volume percent water. The water sorption isotherm of the mucus trail can be described through a Flory–Huggins polymer/solvent interaction parameter of χ=0.54±0.1, which is comparable to the value for some synthetic hydrophilic polymers, such as poly(vinyl pyrrolidone).

The purpose of this study was to investigate the cause of hip complaints following conformal neutron therapy delivered by opposed lateral and oblique anterior ports to treat prostate cancer. Twenty-seven patients with hip complaints following neutron or mixed neutron and photon therapy for prostate cancer had 34 magnetic resonance imaging (MRI) studies 3-39 (mean 15.3) months following treatment; for comparison, 13 similarly treated patients without hip complaints were imaged 1-32 (mean 13.8) months post-treatment; 25/40 imaged patients received concurrent nonsteroidal hormone therapy. Coronal and axial images of the hips/pelvis were obtained utilizing T1 weighted spin echo and fat suppressed inversion recovery (STIR) sequences. Signal amplitude (SA) of involved muscles was measured on the STIR images and normalized to that of the psoas outside the treatment field. Hip complaints ranged from mild soreness or motion limitation to severe pain and limitation of ambulation; presence and severity of symptoms (sx) were significantly related to neutron dose (P = 0.020 and 0.0001) but not to hormone therapy (each P0.17). Normalized SA of the obturator muscles differed significantly with neutron dose (P = 0.013), the presence, and the severity, of sx (P = 0.0002 and 0.0007); estimated extent of abnormal muscle also differed significantly with neutron dose (P = 0.039), presence, and severity, of sx (P = 0.00004 and 0.0007); [hormone treatment had a profound effect on SA (P = 0.0001) and extent (P = 0.005) which was independent of sx (P = 0.10 and 0.14, respectively) and neutron dose (P = 0.33 and 0.32, respectively)]. Subcutaneous changes localized lateral to the greater trochanter were seen in all, and edema of the subjacent gluteus muscles in many, symptomatic hips; only 4/13 asymptomatic hips showed subcutaneous changes, 6 had mild gluteus edema. Avascular necrosis of the femoral head was seen in 5 symptomatic hips, with marked acetabular necrosis in 3 of these; small joint effusions were seen in 8 symptomatic hips; asymptomatic hips had no significant bone or joint abnormalities. Neutron therapy for prostate cancer designed to spare the rectum results in significant dose-dependent, musculoskeletal complications which are well demonstrated by MRI. SA abnormalities of irradiated muscle correlate significantly with neutron dose and both presence and severity of hip sx. Protocol modifications have been implemented to reduce these complications. MRI provides an objective means to assess both complications and the success of new protocols in ameliorating them. Concurrent hormone therapy has a profound effect on muscle changes on MRI which is independent of neutron dose and sx.

L-692,429 is a novel nonpeptidyl growth hormone secretagogue that has been demonstrated to stimulate growth hormone secretion in rats, dogs, and humans after intravenous administration. We have examined the pharmacokinetics and disposition of L-692,429 in male Sprague-Dawley rats, beagle dogs, and chimpanzees. Plasma clearance (CLp) of L-692,429 in dogs after intravenous dosing was approximately 18 ml/min/kg and was constant between the doses of 0.1 and 0.9 mg/kg. In rats, CLp after intravenous dosing increased from 3 to 12 ml/min/kg in a dose-dependent manner between 0.1 and 5 mg/kg. In chimpanzees, CLp after an intravenous dose of L-692,429 at 0.5 mg/kg was 5.7 ml/min/kg. In vitro binding of L-692,429 to plasma proteins of dogs, chimpanzees, and humans was approximately 87%, 94%, and 93.5%, respectively, and was independent of concentration. In contrast, plasma binding of L-692,429 was concentration-dependent in rats and decreased from 98.5% to 90.6% between 0.01 and 10 micrograms/ml. Metabolism of L-692,429 was minimal in rats, but moderate in dogs, with the major metabolite being a derivative monohydroxylated at the benzolactam moiety. Thus, the faster clearance of L-692,429 in dogs likely is caused by less extensive plasma protein binding and higher metabolic clearance. The nonlinear pharmacokinetics in rats probably is the result of concentration-dependence in plasma binding. The results of these studies suggest that plasma protein binding plays a major role in determining the values of CLp of L-692,429 among the species. After an intravenous dose of [3H]L-692,429 to rats, liver, kidney, lung, and heart had the highest levels of radioactivity at the early time points, but the gastrointestinal tract had increasing concentrations at later time points. Most of the radioactivity was cleared from all tissues by 24 hr, indicating that L-692,429 did not accumulate in tissues. After intravenous dosing of [3H]L-692,429 to rats and dogs, recoveries of total radioactivity in urine and feces corresponded to approximately 10% and 90%, respectively. Greater than 70% of radioactivity was recovered in bile of rats within 24 hr after intravenous dosing of [3H]L-692,429, indicating that biliary excretion was the primary route of elimination. Based on the combined recoveries of the radioactive dose in bile and urine after an oral dose of L-692,429, oral absorption in rats was approximately 3%. The poor absorption may be the result of the zwitterionic nature of this compound.

By influencing the regulation of the mechanisms of angiogenesis, erythropoietin production, blood flow, myocardial glucose uptake, glycogenolysis, systolic blood pressure, respiration, plasma norepinephrine and epinephrine levels, adenosine may exert a significant effect on the body's adaptation response to exercise. However, adenosine's possible influence over the vasodilatory response to exercise in skeletal muscle is controversial and more research is required to resolve this issue. Various popular exercise training methods, such as cyclic training, interval training, and the 'warm down' from training may increase adenosine levels and thereby might enhance the response of adenosine-influenced adaptive mechanisms. Among the several classes of drugs which may enhance extracellular adenosine levels and thereby might augment adenosine-influenced adaptive mechanisms, are the anabolic steroidal and some readily available non-steroidal anti-inflammatory drugs (NSAIDs).

A diphthalocyanine disulfide (Pc) molecule has been deposited as a monolayer on gold-coated substrates through the process of self-assembly. To establish the molecular orientation of the Pc molecule on the gold surface the two complementary techniques of transmission IR and reflection absorption IR (RAIR) spectroscopies were used. The appearance of IR absorption bands associated with the Pc nucleus in the transmission spectrum, and their absence in the RAIR spectrum, suggests that the Pc self-assembled monolayer (SAM) is orientated with the macrocycle parallel to the metal surface. The Pc SAM has been used in conjunction with surface plasmon resonance (SPR) to establish the utility of combining these techniques for optical gas sensing. The SPR reflectivity curves for the gold substrate and the Pc SAM on the gold substrate have been obtained. On exposure of the Pc SAM to the environmentally important NO2 gas, changes of the reflectivity signal were obtained in proportion to the concentration of the analyte gas. The results obtained show that the monolayer deposition technique of self-assembly is an ideal method for the production of chemically sensitive substrates which can be combined with surface plasmon resonance for the optical sensing of gaseous species.

Self-assembled monolayers of three straight-chain alkanethiols [CH3(CH2)nSH, n= 11, 15, 17] have been formed on a gold substrate from cyclohexane solution and characterised using IR spectroscopy. Over a period of ca. six months, the relative intensities of the C–H stretching bands in the IR spectra were observed to change. These changes are explained by a tilting of the molecules from their initial position away from the surface normal upon oxidation of the thiolate root. This temporal dependence of the tilt angle has implications for the stability of self-assembled monolayers.

Largactil has been used in Shaughnessy Hospital in a total of 330 cases. The drug was used intravenously during surgery, and orally and intramuscularly in conjunction with usual premedication. in general the intramuscular route was felt to be the most satisfactory.

A study has been made of the response of normal lithium fluoride and that depleted of 6Li when exposed to pure gamma rays and to the mixed neutron-plus-gamma fields of reactors. Results from a stud...

A simple one antenna X-band transmitter-receiver for demonstrating the Doppler shift from a moving metal reflector is described. A 132-scale slot car and track provide a convenient constant-speed target whose speed is measured by the Doppler shift. The usable range is over 20 ft.

When exposed to a source of ionizing radiation of doses ranging from 10/ sup 6/ to 10/sup 10/ ergs/g carbon, nitrous oxide decomposes linearly as a function of the absorbed dose in the ratio N/sub 2/: O/sub 2/: NO/sub 2/: 1.0: 0.14; 0.48 as stable products. With the addition of a small amount of U/sup 235/ to the dosimeter, the gas can be used in neutron dosimetry. The principle of Hartech and Dondes was utilized in the development of nitrous oxide in the dosimetry program associated with the Lockheed Radiation Effects Reactor (RER). This has included the design of practical dosimeters and vacuum analytical apparatus, equipment calibration, and the development of a routine method. Although the reactor exposure data produced a similar curve to that of the pure gamma data, there are definite indications of the neutron effect in the decomposition values of the gas bias the gamma dose. However, the expected break in the decomposition curve is obtained at the equivalent dose of 10/sup 11/ ergs/g carbon. The advantages of nitrous oxide as a total-dose dosimeter include post-irradiation stability, flexibility, and economy. It is adaptable to a variety of uses, including high-flux material testing and total-dose monitoring in areasmore » of high radiation exposure.« less

SummaryThe addition of 4% 1:20 liver concentrate to purified rations increased the rate of growth and aided in the maintenance of a general healthy appearance of rabbits. The improved performance noted when liver extract was added is apparently not attributable to known nutrients including folic acid, biotin, p-aminobenzoic acid and cystine. The results indicate that liver contains an unidentified factor essential for the maximum rate of growth of the rabbit.

An attempt has been made to review the pertinent literature on the subject of chronic pulmonary emphysema where it may have some bearing on the practice of anaesthesia Some dogmatic statements may have been made concerning procedures and techniques, particularly on the problem of anaesthetic management, but these by no means constitute the perfect solution to this serious problem. In addition to a knowledge of normal pulmonary physiology and function tests, the anaesthetist should be well aware of the abnormal physiology and altered function tests which are a part of this disease. Pulmonary function studies should perhaps be used more frequently along with a basis of classification for severity of disease. The anaesthetic risk would then be more easily computed and the optimum anaesthetic management would then follow.

An anthropometric survey of limited scope was undertaken in October and November 1966, involving 200 Royal Air Force and Royal Navy aircrew. The 44 measurements taken on each subject were mainly those used in the drafting of patterns for the R.A.E. experimental range of aircrew functional garments. The acquired data have been tabulated and presented in a form primarily suitable for functional clothing sizing purposes. Tables and graphs are also included which give the data in a form suitable for use in aircrew work-space studies etc. Comparisons are made between specimen garment size-rolls for the 200 subjects based on chest girth/torso hoop, chest girth/stature and weight/stature as control parameters. From the experience gained during this survey, suggestions are made regarding measuring techniques and procedures.