Showing papers by "Research Triangle Park published in 1973"
TL;DR: The possibility exists that extra 14th ribs could be regarded as indicators of teratogenic potency of a drug at some higher dosage; but the data presented did not demonstrate the usefulness of the other skeletal variants examined as signals ofTeratogenic potential.
Abstract: Skeletal variations were studied in 20-day rat fetuses from pregnant females given acetazolamide, actinomycin D, or sodium salicylate and in vehicle-treated and untreated controls. A slight increase over untreated control values as regards resorptions, malformations, and certain skeletal variants was noted in some vehicle-treated groups. Supernumerary 14th ribs were designated as rudimentary (less than half the length of the 13th rib) or extra (half or greater than half the length of the 13th rib) on the basis of actual measurement showing a bimodal distribution in length. The occurrence of rudimentary 14th ribs was highly variable after vehicle or teratogen treatment. Extra 14th ribs occurred in a dose-related fashion after actinomycin D (days 7 and 9) and sodium salicylate (which sometimes also produced 15th ribs), but not after acetazolamide treatment. Sternebrae were variable in form after most treatments and these changes showed a slight but insignificant increase after actinomycin D or sodium salicylate on day 9. The incidence of variations of vertebral centra was highly changeable after all treatments but was consistently greater after sc treatment with water or acetazolamide and appeared to be dose related after sodium salicylate. The authors believe that none of these skeletal variants should in themselves be considered as malformations. The possibility exists that extra 14th ribs could be regarded as indicators of teratogenic potency of a drug at some higher dosage; but the data presented did not demonstrate the usefulness of the other skeletal variants examined as signals of teratogenic potential.
206 citations
TL;DR: Multiple studies have confirmed that TMP-SMZ has a wide spectrum of in vitro activity, and the only outstanding exception is Pseudomonas aeruginosa, from heavy inocula, resistance to TMP develops rapidly, but the rate is markedly reduced by the presence of SMZ.
Abstract: The ultimate effect on bacteria of trimethoprim (TMP) and sulfamethoxazole (SMZ) is to deprive them of folate coenzymes; the spectra of in vitro activity of TMP and SMZ are therefore similar although TMP is usually 20-100 times more active than is SMZ. The synergy of TMP and SMZ can be demonstrated in vitro by increases in bacteriostatic and bactericidal activities. There is an optimal ratio for producing these effects, and it corresponds to the ratios of the MIC of each drug when acting alone; however, synergy does occur over a wide range of ratios. The in vitro activity of TMP-SMZ depends on the medium in which it is measured; traces of thymidine will almost completely abolish activity. The size of the inoculum also affects activity. The activity is not affected in vitro or in vivo by the presence of exogenous folates except in the case of Streptococcus faecalis. Resistance to one of the drugs as measured by conventional tests may not abolish synergy; synergy is maximal, however, when the organism is susceptible to both drugs. Multiple studies have confirmed that TMP-SMZ has a wide spectrum of in vitro activity. The only outstanding exception is Pseudomonas aeruginosa. From heavy inocula, resistance to TMP develops rapidly, but the rate is markedly reduced by the presence of SMZ. The retarding effects of the sulfonamide depend on the degree of susceptibility of the organism and become small with highly resistant strains. R-factors conferring resistance to TMP have been identified, although at present they are rare. Susceptibility testing presents no problems provided a suitable medium and a small inoculum are used. A single combined disk containing 1.25 tg of TMP and 23.75 9g of SMZ is adequate for routine tests.
197 citations
TL;DR: In this article, the perturbational molecular orbital treatment of hyperconjugation (σ-π conjugation) is applied to rationalize trends in a number of experimental properties of compounds of C, Si, Ge, and Sn.
183 citations
TL;DR: Three lines of evidence suggest that the single period of edema formation produced by the intrapleural injection of carrageenin in the first 5 hr is analogous to the second phase of the biphasic rat hindlimb reaction to this irritant.
Abstract: SummaryThe intrapleural injection of 500 μg of carrageenin produces an acute inflammatory reaction in the rat in which it is possible to recover quantitatively the inflammatory cells that are mobilized and the exudate. The time courses of exudate formation and neutrophil mobilization strongly suggest that these phenomena are related. Both curves are sigmoid, and increase sharply between the first and third hours. Aspirin at 90 mg/kg, p.o., produced 83% inhibition of exudate formation at three hours but by the seventh hour the inhibition was only 31%. Neutrophil mobilization was only slightly inhibited by aspirin at three hours. However, the neutrophil mobilization which occurred between the third and seventh hours was completely blocked by aspirin. Monocyte mobilization started two hours after injection of the carrageenin and continued at a fixed rate through the seventh hour. There was no mobilization of monocytes in the aspirin-treated animals for the first five hours. Thereafter the rate of mobilizatio...
176 citations
TL;DR: The combination, TMP-SMZ, has a broader spectrum of antimicrobial activity, is more rapidly bactericidal, and is less susceptible to the development of resistance, than either of the component drugs.
Abstract: Tetrahydrofolate (FAH4) participates in biosynthetic reactions that are vital to cellular growth and survival. In microorganisms, dihydrofolate (FAH2) is synthesized de novo from p-aminobenzoic acid. In mammals, folic acid (FA), FAH, and FAH4 are assimilated from food. In all species FAH4 is reoxidized to FAH2 in the synthesis of thymidylate, and the enzyme, dihydrofolate reductase, is essential to the maintenance of FAH4 pools. Trimethoprim (TMP) selectively inhibits microbial reductases, but its effectiveness is strikingly enhanced when the synthesis of FAH2 is simultaneously blocked by sulfamethoxazole (SMZ). The combination, TMP-SMZ, has a broader spectrum of antimicrobial activity, is more rapidly bactericidal, and is less susceptible to the development of resistance, than either of the component drugs.
148 citations
TL;DR: The novel heme prosthetic group of Escherichia coli NADPH-sulfite reductase (EC 1.8.1.2) has been identified as an iron tetrahydroporphyrin of the isobacteriochlorin type (adjacent pyrrole rings reduced) with eight carboxylic acid side chains.
140 citations
TL;DR: Kinetic parameters suggest a possible influence on ACh synthesis of the in vivo concentration ratio, CoA/acetyl‐CoA, on the basis of a Theorell‐Chance mechanism.
Abstract: — Choline acetyltransferase (EC 2.3.1.6) was partially purified from human caudate nucleus and putamen, human sciatic nerve, rabbit and rat brain, and rabbit sciatic nerve. Kinetic constants were determined under the same conditions for all six extracts. Extrapolated Km values were between 6.6 and 18 μM for acetyl-CoA and between 0.4 and 1.2 mM for choline. Product inhibition patterns indicated that ChAc from both central and peripheral nervous tissues of man and the rabbit obeys a Theorell-Chance mechanism. Kinetic parameters suggest a possible influence on ACh synthesis of the in vivo concentration ratio, CoA/acetyl-CoA.
107 citations
TL;DR: It is recommended that a lower limit of acceptability for dissolution-rate be established for dissolve-rate for digoxin tablets to be used in patients.
106 citations
TL;DR: Laryngo- tracheobronchitis was the major condition productive of excess, acute, lower-respiratory disease in children in heavily polluted communities in the Salt Lake Basin and Rocky Mountain communities.
Abstract: Studies carried out in four distinct geographic areas of the United States involving 20,472 children and adults clearly linked excessive, acute respiratory disease with communities heavily polluted with sulfur dioxide and suspended sulfates. Pollution exposure of three years or longer was an important component in increased risk for acute respiratory disease. Laryngo- tracheobronchitis was the major condition productive of excess, acute, lower-respiratory disease in children in heavily polluted communities in the Salt Lake Basin and Rocky Mountain communities. The effect of pollution on excess, acute respiratory disease was found to be independent of socioeconomic status and cigarette smoking.
84 citations
TL;DR: The findings furnish direct, quantitative support for the idea that it is the inhibition of orotidine 5'-phosphate decarboxylase by the nucleotides of oxipurinol that is primarily responsible for the increased urinary excretion of Orotic acid and orotazine in patients treated with allopurinols.
83 citations
TL;DR: It is concluded that the enzymatic locus of action of the compound is dihydrofolate reductase, and the selective action of TMP is based on its ability to distinguish structural differences in reductases isolated from various organisms.
Abstract: The biochemical basis of the activity of trimethoprim (TMP) is reviewed. It is concluded that the enzymatic locus of action of the compound is dihydrofolate reductase. The selective action of TMP is based on its ability to distinguish structural differences in reductases isolated from various organisms. The chemical nature of these variations in species may consist of changes in certain amino acids in regions adjacent to the active site of the reductase. Attention is directed to areas in which our knowledge of the biochemistry of TMP is incomplete.
TL;DR: Findings suggest that control mechanisms can maintain uridine nucleotide levels in a normal range, even in the presence of strong inhibitors of de novo UMP biosynthesis.
TL;DR: It was concluded that initiation of protein synthesis can occur with unformylated met-tRNA(F) in E. coli.
Abstract: Escherichia coli grew exponentially at a reduced rate in the presence of 50 or 100 μg of trimethoprim/ml if the low-molecular-weight products of folate metabolism or their precursors (thymidine, purines, methionine, glycine, and pantothenate) were supplied in the medium. Folate metabolism was inhibited 99.9% by these concentrations of trimethoprim, but a low level of formylation of methionyl transfer ribonucleic acid (met-tRNAF) could be detected. However, in a medium containing all major amino acids, nucleosides, and vitamins, formylation of met-tRNAF was undetectable in the presence of trimethoprim. No other amino-masked amino acids were detected, and methionine remained a major amino-terminal amino acid of mature proteins. met-tRNAF was rapidly labeled with exogenous methionine and was associated with 30s ribosomal subunits and 70s ribosomes. It was concluded that initiation of protein synthesis can occur with unformylated met-tRNAF in E. coli. Changes in macromolecular composition were associated with the lack of formylation, in particular a fourfold increase in both met-tRNAF and ribosomal subunits. These changes would tend to compensate for the low specific rate of initiation with unformylated met-tRNAF.
TL;DR: The plasma polymerization of organic compounds was used to prepare a composite reverse osmosis membrane which consists of an ultrathin semipermeable membrane formed by plasma polymerisation of an organic compound or compounds and a porous substrate as mentioned in this paper.
Abstract: The plasma polymerization of organic compounds was used to prepare a composite reverse osmosis membrane which consists of an ultrathin semipermeable membrane formed by plasma polymerization of an organic compound or compounds and a porous substrate. Many nitrogen-containing compounds (aromatic amines, heteroaromatic compounds, aliphatic amines, and nitriles) were found to yield excellent reverse osmosis membranes by plasma polymerization directly onto porous substrates such as Millipore filters, porous polysulfone filters, and porous glass tubes. Factors involved in the preparation of reverse osmosis membranes by plasma polymerization were investigated and discussed. The plasma polymerized membranes have the following unique features: (1) very stable performance independent of salt concentration and applied pressure (practically no water flux decline was observed with many membranes): (2) salt rejection and water flux both increase with time in the initial stage of reverse osmosis (consequently, the performance of the membrane improves with time of operation); (3) very high salt rejection (over 99%) with high water flux (up to 38 gfd) can be obtained with 3.5% NaCl at 1500 psi (membranes perform equally well under conditions of sea water conversion and brakish water treatment).
TL;DR: A more accurate, easy to perform technique with the use of xylene has been developed for determining the difference between the attachment and ingestion of polystyrene latex spheres.
Abstract: Phagocytosis is a two-step process involving attachment and ingestion of particulate material. It is often difficult to determine under a light microscope whether the particles are actually ingested or are merely attached to the cell. A more accurate, easy to perform technique with the use of xylene has been developed for determining the difference between the attachment and ingestion of polystyrene latex spheres. The xylene treatment dissolves the extracellular spheres, leaving only the intracellular spheres to be counted by the experimenter to obtain a more accurate phagocytic index. This technique also allows an investigator to get an ingestion index, an attachment index, or both.
TL;DR: In this paper, the small-angle x-ray scattering (SAXS) patterns of a number of linear polyethylene and polyoxymethylene (POM) samples have been measured and compared to the intensity functions of one-dimensional paracrystalline lattices.
Abstract: The small-angle x-ray scattering (SAXS) patterns of a number of linear polyethylene (PE) and polyoxymethylene (POM) samples have been measured and compared to the intensity functions of one-dimensional paracrystalline lattices. It was found that the ratio of the angular positions of the second and first scattering maxima (θ2/θ1) is generally less than or equal to 2.0, implying that the paracrystalline lattice statistics are symmetric or moderately skewed to larger periods. The Bragg spacing (“long period”) of such samples is within 3% of the identity period of the macrolattice. With quenched POM the ratio θ2/θ1 is substantially larger than 2.0, which indicates either extremely asymmetric lattice statistics or coexisting structures within the material. From consideration of the reduced widths of the first scattering maxima, it was found that some broadening is present in addition to that from the paracrystallinity. This excess broadening could result from a finite lattice length of ∼1000 A. The need for careful experimental technique for obtaining the actual position of the scattering maximum is emphasized. In addition, it is demonstrated that the scattering curve and the correlation function of the system yield essentially the same apparent structural periods.
TL;DR: In this paper, the effects of gas plasma generated by electrodeless glow discharge on polymers were investigated as functions of gas pressure, discharge power, exposure time, and type of plasma gas.
Abstract: The effects of gas plasma generated by electrodeless (inductive coupling) glow discharge on polymers were investigated as functions of gas pressure, discharge power, exposure time, and type of plasma gas. A remarkable similarity between the plasma susceptibilities of low molecular weight organic compounds and polymers was observed; i.e., polymers which have ether, carbonyl, ester, or carboxylic acid attached to a nonaromatic structure are very susceptible to plasma. The weight loss was proportional to the exposure time and exposed area. The discharge power and type of gas were found to have a great influence on both the rate of weight loss and the morphology of the exposed surface. The predominant effect of plasma on polymers was found to be degradation (manifested by weight loss). The crosslinking effect was found to be marginal with many polymers; however, significant crosslinking was observed with double bond-containing polymers. The crosslinking was examined by swelling the treated films. With copolymers of styrene–butadiene, 4-vinylpyridine–butadiene, methacrylic acid-butadiene, and acrylic acid–butadiene, the crosslinking was greatly dependent on the discharge power, the butadiene content of the copolymers, and the exposure time. Both degradation and crosslinking by gas plasma were generally limited to the exposed surface; however, the propagation of crosslinking in the direction of thickness was observed with copolymers of styrene–butadiene. The plasma of organic vapor also cause degradation of plasma-susceptible polymers, particularly at high wattage, although the deposition of polymer occurs simultaneously.
TL;DR: Results indicated that adenosine was directly phosphorylated to 5'-adenosine monophosphate by a nucleoside kinase, and inosine appeared to proceed to the nucleotide, at least partially, through an initial conversion to hypoxanthine.
Abstract: 14C-Labeled adenosine, inosine, hypoxanthine, and adenine were extracted by the isolated rat heart in amounts proportional to their concentration in the perfusion medium between 0.05 and 5 µM. With each of the precursor materials, nearly all of the radioactivity retained by the heart was identified as acid-soluble nucleotide. Nucleotide formation from the four isotopic precursors occurred at similar rates when the concentration of the precursors was below 1 µM. Above this concentration, the heart appeared to utilize adenosine for nucleotide synthesis at rates three to five times those for the other purines. Several experimental approaches were employed to determine the predominant enzymatic routes in the rat heart for the conversion of the nucleosides adenosine and inosine to nucleotides. The results indicated that adenosine was directly phosphorylated to 5'-adenosine monophosphate by a nucleoside kinase. Inosine appeared to proceed to the nucleotide, at least partially, through an initial conversion to h...
TL;DR: In this article, the authors used the scanning Michelson interferometer, cooled solid state detectors, the fast minicomputer, and the multiple pass long path cell for infrared detection of air pollutants.
Abstract: Infrared detection of air pollutants has been extended to the parts-per-billion sensitivity range. The increased detection sensitivity results from the use of the scanning Michelson interferometer, cooled solid state detectors, the fast minicomputer, and the multiple pass long path cell. Forming ratios of spectra with the aid of the computer extracts obscure information and minimizes the interferences of atmospheric water and carbon dioxide. Almost all of the significant gaseous pollutants can be measured by the method described, even at concentrations smaller than one part pollutant to one billion parts air.
TL;DR: An enzymic basis is established for the evidence obtained in vivo which indicate that malaria synthesize their folate cofactors de novo, and it is suggested that the antimalarial action of sulfonamides and DDS is due to their inhibition of plasmodial H2pteroate synthetase.
Abstract: SYNOPSIS. Cell-free extracts of the rodent malaria parasite Plasmodium berghei synthesized dihydropteroate (H2pteroate) and dihydrofolate (H2folate) from 2-amino-4-hydroxy-6-hydroxymethyl-7,8-dihydropteridine (hydroxymethyldihydropteridine) and p-aminobenzoate (pAB) or p-aminobenzoylglutamate (pABG). The reaction was demonstrated also in extracts of Plasmodium gallinaceum, Plasmodium lophurae and Plasmodium knowlesi, by the use of a microbiologic assay method and pABG as cosubstrate.
Some of the properties of the enzymes involved were investigated in P. berghei preparations, utilizing a radioactive assay which measures the conversion of [7-14C]pAB to [14C]H2pteroate. Apparent Km values of 0.28 μM for [7-14C]pAB, 0.037 mM for pABG and 0.8 μM for hydroxymethyldihydropteridine were obtained. The reaction had absolute requirements for ATP and Mg++, and was stimulated by dithiothreitol. The enzymes required for the reaction were eluted together from Sephadex G-200 columns in a molecular weight range of 200,000–250,000. In bacteria hydroxymethyldihydropteridine is converted 1st by a pyrophosphokinase to pyrophosphorylmethyldihydropteridine, and this compound is then condensed with pAB to form H2pteroate by H2pteroate synthetase. Both enzymic activities were demonstrated in P. berghei preparations and separated by DEAE-Sephadex chromatography.
The enzymic synthesis of H2pteroate by P. berghei is inhibited by several sulfonamides and diaminodiphenylsulfone (DDS). The latter compound is shown to be competitive with pAB, with a Ki value of 0.38 μM; pABG is also a competitive inhibitor. These data establish an enzymic basis of support for the evidence obtained in vivo which indicate that malaria synthesize their folate cofactors de novo. It is suggested that the antimalarial action of sulfonamides and DDS is due to their inhibition of plasmodial H2pteroate synthetase.
TL;DR: Analysis of daily mortality for 422 places in the United States from 1962 to 1966 provided a consistent set of mortality predictors of three classes: annual cycle, day of week, and Christmas holidays; influenza epidemics; and days or spells of extreme cold or heat.
Abstract: Analysis of daily mortality for 422 places in the United States from 1962 to 1966 provided a consistent set of mortality predictors of three classes: annual cycle, day of week, and Christmas holidays; influenza epidemics; and days or spells of extreme cold or heat. Analysis of deaths for New York metropolitan region, with daily SO2 measurements in Manhattan at the Davis Laboratory, showed the pollution measurement contributes significantly to prediction of deaths. Mortality was 1.5% iess than expected on 232 days with SO2 levels below 30μg/cu m and 2% greater than expected on 260 days with SO2 levels above 500μg/cu m, after correcting for the other factors. Coefficient of haze (COHS) does as well as SO2 in predicting death. A parallel analysis in the Philadelphia area showed similar, but weaker, SO2 and COHS effect.
TL;DR: In this paper, the rates of polymer deposition from various olefinic monomers in an electrodeless glow discharge were studied, and it was found that the polymer deposition is controlled by the monomer flow rate and Ro (in pure monomers flow) is proportional to the flow rate of monomer Fw (based on the weight).
Abstract: The rates of polymer deposition from various olefinic monomers in an electrodeless glow discharge were studied. The previously found empirical relationship (with styrene in part I) between the rate of polymer deposition R, the monomer pressure pM, and gas pressure px in a steady-state flow system (i.e., R = a(pM)2 [1 + b(px)], R being nearly independent of the discharge power) was also found with all monomers investigated. (The effect of gas was examined with nitrogen in this study.) However, it was found that the polymer deposition is controlled by the monomer flow rate and Ro (in pure monomer flow) is proportional to the flow rate of monomer Fw (based on the weight); i.e., Ro = kFw, where k is a characteristic rate constant of the polymerization. Olefinic monomers can be generally classified into two major groups, i.e., type A monomers which predominantly polymerize, and type B monomers which decompose in a glow discharge. Type B monomers have smaller values of a and k compared to type A monomers. The values of a and k for type A monomers both increase with increasing molecular weight of the monomer. The values of k for all monomers investigated are within roughly an order of magnitude, indicating that the reactivity levels of monomers are very similar in a glow discharge polymerization.
TL;DR: In this paper, the rates of polymer deposition from various organic compounds which do not contain an olefinic doublebond in an electrodeless glow discharge were studied, and the results showed that the polymerization rates of these unconventional monomers are by and large similar to those reported in the previous study.
Abstract: The rates of polymer deposition from various organic compounds which do not contain an olefinic doublebond in an electrodeless glow discharge were studied. The polymerization rates of these unconventional monomers are by and large similar to those of olefinic monomers reported in the previous study (part II). The rate of polymer deposition R0 from pure monomer flow can be characterized, according to the analysis used in part II, by Ro = apM2 and R0 = kFw, where pM is the vapor pressure of the monomer, Fw is the weight basis flow rate of the monomer. Type A monomers which predominantly polymerize and type B monomers which decompose in a glow discharge were also found with these unconventional monomers. The effects of structural factors on the values of a amd k and on the classification of types A and B were examined. These structures and groups—aromatic, heteroaromatic, nitrogen-containing (e.g., >NH,NH2,CN), Si-containing, and olefinic doublebond—favor the polymerization. These structures and groups—oxygen-containing chlorine, aliphatic hydrocarbon chains, and cyclic hydrocarbon chains—favor the decomposition of the monomer in a glow discharge. It is postulated that the polymerization of organic compounds proceed by the recombination of excited species (probably free radicals) created by glow discharge and reexcitation followed by further recombinations in the vapor phase and at the interface.
TL;DR: Improved procedures for extraction of polar metabolites and for enzymic cleavage of conjugated products were applied and a new metabolite, the 3-oxide of TMP, was identified, and urinary levels of this product were also measured.
Abstract: Urinary concentrations of trimethoprim (TMP) and its metabolites were measured in eight healthy subjects after oral administration of 160 mg of TMP in two tablets of Septra@ (trimethoprim-sulfamethoxazole). Improved procedures for extraction of polar metabolites and for enzymic cleavage of conjugated products were applied. The 1-oxide and conjugates of demethylated metabolites were found in substantially higher concentrations than those previously reported. A new metabolite, the 3-oxide of TMP, was identified, and urinary levels of this product were also measured.
TL;DR: The fraction of ribosomes engaged in protein synthesis in Escherichia coli growing at specific growth rates ranging from 0.3 to 1.2 h(-1) was estimated and the increase in the fraction of polyribosomes had begun within 30 s after a shift-up from glucose-minimal medium, and was complete within 2 to 5 min, indicating that the function of Ribosomes is regulated.
Abstract: The fraction of ribosomes engaged in protein synthesis in Escherichia coli growing at specific growth rates ranging from 0.3 to 1.2 h−1 was estimated from measurements of nascent protein/ribosome and of polyribosomes. Both measurements showed that the fraction of ribosomes synthesizing protein increased with specific growth rate, from 30 to 70% over the range studied. Polyribosome measurements made at different specific growth rates in four E. coli strains showed no significant differences between strains. The increase in the fraction of polyribosomes had begun within 30 s after a shift-up from glucose-minimal medium, and was complete within 2 to 5 min. These results indicate that the function of ribosomes is regulated.
TL;DR: The anesthetic activity and acute toxicity of the optically pure enantiomers of various disubstituted barbituric acids containing and optically active 5-(1-methylbutyl)alkyl group and of their racemates was determined in mice after iv and ip administration.
TL;DR: The free ends of microfibrils are point vacancy defects of the micro-fibrillar superlattice which, under applied stress, open and form microcracks long before the sample fails.
Abstract: Drawn crystalline polymers, fibers and films, exhibit a characteristic fibrous structure with the long and narrow microfibril as the basic element. The highly oriented microfibrils originating from the same stack of parallel lamellae of the starting material form the fibril which, as a rule, differs a little in drawing ratio from adjacent fibrils. As a consequence of this variation and the location of the ends of microfibrils on the outer boundary of the fibril, this is the area of reduced strength where the fracture phenomena start. The free ends of microfibrils are point vacancy defects of the microfibrillar superlattice which, under applied stress, open and form microcracks long before the sample fails. The radial crack propagation first breaks the microfibrils adjacent to the microcrack at the point vacancy and produces a great many radicals as a consequence of the rupture of tie molecules in at least one amorphous layer of each broken microfibril. Longitudinal crack propagation proceeds alon...
TL;DR: For the cause-specific analyses, the pattern of mortality was reasonably consistent for each analysis sub-category implying that excess deaths were not solely due to any of these three specific principal causes.
TL;DR: In this paper, the effect of particle size and interparticle "gap" lengths on the small-angle x-ray scattering of a paracrystalline one-dimensional macrolattice has been examined.
Abstract: The effect of previously proposed distributions of particle size and interparticle “gap” lengths on the small-angle x-ray scattering of a paracrystalline one-dimensional macrolattice has been examined. It was concluded that the general paracrystalline model, in which the fluctuations of crystalline and amorphous thickness both contribute to the destruction of long-range order, best describes the structure of lamellar aggregates in semicrystalline polymers. By using this model, the influence of symmetric and asymmetric lattice statistics on the positions of the scattering maxima were investigated. It was found that positively skewed thickness distributions result in the second-order maximum occurring at an angle greater than twice that of the first-order maximum (sx2/sx1 > 2.0); the position of the first-order maximum is generally greater than the Bragg angle of the structure. With negatively skewed distributions, the ratio of the scattering angles, sx2/sx1, is less than 2.0, and the first maximum is displaced below the Bragg angle. Qualitatively similar behavior is found with lattices characterized by symmetric lattice statistics, though these deviations from the Bragg conditions are smaller than in the case of negatively skewed distributions. The ratio of the scattering angles of the second and first maxima best reflects the general shape of the lattice statistics in a paracrystalline lattice. The effect of a transition zone, having properties intermediate between those of the crystalline and amorphous regions, was also considered. While the intensity of the higher-order maxima is decreased, no significant shift of the scattering angles results from the incorporation of such a transition zone.