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In image processing, leaf shape recognition requires a huge database of similar images. Normal leaf image database construction requires more time and space. On the other hand, mobile offline applications are not able to contain huge image database with high pixel ratio. To solve this problem, mainly in medicinal plant identification, small leaf descriptors are necessary to completely provide the required plant information. Presently, the Botanists use shape reference table to recognize the following shapes of the leaf: ovate, cordate, elliptical, oblong, lanceolate and linear. As the shape numbers are invariant under scale, rotation and translation, which is highly desirable property for object recognition and chain code techniques preserve data by allowing large data reduction. Hence, in the proposed Shape Descriptor Algorithm for Medicinal Plant Identification (SDAMPI), we developed a descriptor to resolve the pixel selection issue of Freeman chain code and generate a unique leaf shape number. This leaf shape digital descriptor will act as a reference table for medicinal plant leaf shape identification. The performance of the proposed descriptor is evaluated through Jaccard similarity index graph and Levenshtein distance (LD) graph. From the results, it is confirming that, SDAMPI descriptor can detect Medicinal plant leaf shapes more accurately than existing methods.

Funding Acknowledgements This is an unfunded project Background Early mobilization is considered as a complex task in an intensive care unit (ICU) and patients are often on prolonged bed rest leading to physical deconditioning. Intensive care early mobility programs have been recognized to be safe and have shown positive outcomes. However, implementing early mobility program as a standard of care remains a challenge. Coronary Intensive Care Unit (CICU) provides complex care for cardiac critically ill patients. In February 2018, the CICU multidisciplinary team (MDT) started a quality improvement project to implement early mobility program in the unit. Purpose This project aimed to investigate the feasibility of implementing an Early Mobility Protocol in CICU to increase the number of patients mobilized to more than 95%. Secondary objective was to explore the impact of the protocol on the mobility level of the patients at the time of discharge or transfer from the CICU. Methods A multidisciplinary mobility task force including Physicians, nurses, physiotherapists and respiratory therapists was formed to analyze the barriers in implementing an early mobility program. A staff survey was conducted to identify the need for a standard early mobility protocol. Root cause analysis and Pareto analysis was done. An evidence based early mobility protocol was developed and implemented. All non-mechanical ventilated patients were included in the first phase and all mechanical ventilated patients were included in the second phase of the project. A standard ICU Mobility scale (IMS) was used for scoring the mobility level of the patients. This quality improvement project is based on "Institute for Healthcare Improvement" model. Periodical staff education and training programs about early mobilization were conducted to improve staff confidence. Change ideas were implemented using multiple Plan Do Study Act cycles. Results The total number of patients included from 1st March 2018 till 31st December 2019 was 2356. This included both the genders. In March 2018, only 68% of non-mechanical ventilated patients were mobilized, that reached to 88% by November 2018. This gradually increased to 100% in May 2019 and is currently sustained at 100%. In November 2019, only 50% of mechanical ventilated patients were mobilized which gradually increased to 66.66% and 75% in middle and end of December 2019. The mean IMS score at discharge or transfer from CICU was "8". From patient-family experience survey, 93.75% of patients perceived that the program was helpful in regaining mobility and 96.25% of patients felt that the program helped in regaining their autonomy. Conclusion The result shows that it is safe and feasible to implement an early mobility program in a Coronary Intensive Care Unit. A standardized mobility protocol can lead to efficient mobilization practice facilitating early transfers from ICUs without any complications. This could further enhance the collaboration of the MDT members leading to culture change in ICUs.

Yogurt is one of the popular dairy products produced by the bacterial fermentation of milk. Researches proved that fruit enriched Rice-based yogurt is good alternative for the traditional yogurt. Hence, four different combinations of rice-based yogurt were prepared by adding rice slurry. Rice-based yogurt containing 25% milk and 75% rice slurry scored best in microbial analysis. Count of both Streptococcus salivarius ssp. thermophilus and Lactobacillus delbrueckii ssp. bulgaricus were higher in this combination but organoleptic quality was poor. The one with 75% milk and 25% slurry scored best in organoleptic analysis as it scored high in all the characters under study. Hence the combination with 75% milk and 25% slurry was selected and was enriched with the fruit pulps of Annona, Papaya and Guava. The one with 20% Annona fruit pulp and one with 5% Papaya fruit pulp were selected as the best combinations as they got the highest overall acceptability score and the count of both the bacteria were higher in these combinations, proved that fruit enrichment doesn’t affect bacteria in yogurt. Cost analysis proved that collection of fruits from wild will help to reduce the price of the yogurt. Thus, Rice-based Probiotic Yogurt with 75% milk and 25% rice slurry with 20% Annona fruit pulp and one with 5% Papaya fruit pulp were developed as best combinations and can replace normal yogurts currently available in the market with low cost.

Accuracy in identification of any plant is achieved by understanding and extracting the plant features. Image processing techniques has gained interest in identifying the plants in realist and accurate manner. Among them, Edge detection techniques has very important role in creation of database for plant identification. Edge filtering and optimization technique to create continuous edges makes Canny edge detection widely popular to retrieve image characteristics. The proposed contour based image segmentation process filter morphological features from plant leaves. Detailed vein and texture extraction of plant leave using Canny edge detector are explained.

Studies on plant identification through image processing consider shape, color and texture features of leafs. But botanist's uses leaf morphology, leaf arrangement, types of venation, leave shapes, leave bases, leaf margins and leaf apices for recognizing a plant. This paper introduces the leaf venation, leaf margin, leaf apies, and leaf bases models for improving plant leaf identification. These new features along with shape, color and feature increases the accuracy of the plant identification.

Aim: The purpose of the survey was to understand the role of positron emission tomography (PET) in clinical radiotherapy practice among the radiation oncologists' in India. Settings and Design: An online questionnaire was developed to survey the oncologists on their use of PET, viewing protocols, contouring techniques practiced, the barriers on the use of PET and the need for training in use of PET in radiotherapy. The questionnaire was sent to about 500 oncologists and 76 completed responses were received. Results: The survey shows that radiation oncologists use PET largely to assess treatment response and staging but limitedly use it for radiotherapy treatment planning. Only manual contouring and fixed threshold based delineation techniques (e.g. 40% maximum standard uptake value [SUV max ] or SUV 2.5) are used. Cost is the major barrier in the wider use of PET, followed by limited availability of FDG radionuclide tracer. Limited or no training was available for the use of PET. Conclusions: Our survey revealed the vast difference between literature suggestions and actual clinical practice on the use of PET in radiotherapy. Additional training and standardization of protocols for use of PET in radiotherapy is essential for fully utilizing the capability of PET.

The Centella asiatica is known as Gotukola. The essential oil is extracted by Clevenger apparatus. The oil yield from whole plant C. asiatica is 0.8 mL in 1 Kg. The essential oil is analyzed by GC‐MS. There are 43 volatile compounds are identified from essential oil of C. asiatica . P‐Cymene‐(44%) is the predominant compound in essential oil of C. asiatica .

NMR spectroscopy of 13C-labeled human low density lipoprotein (LDL) has been employed to characterize the lysine (Lys) residues in apo B-100. Reductive methylation with [13C]formaldehyde converts up to two-thirds of the Lys to the dimethylamino derivative; this pool of Lys is exposed at the surface of the LDL particle. The [13C]dimethyl-Lys which are visualized exhibit resonances at chemical shifts of 42.8 and 43.2 ppm (pH 7.6) indicating that they exist in two different microenvironments; this is a reflection of the native conformation of apo B associated with lipid, because the labeled, reduced, and alkylated protein gives a single resonance when dissolved in 7 M guanidine hydrochloride. The pH dependences of the Lys chemical shifts indicate that the two types of Lys titrate with different pK values; "active" Lys have a pK of 8.9, while "normal" Lys have a pK of 10.5. About 53 active Lys and 172 normal Lys are exposed on the surface of LDL with the remaining 132 Lys which are present in the human apo B-100 molecule being buried and unavailable for methylation. Addition of paramagnetic ions indicates that the active and normal Lys have different exposures to the aqueous phase; apparently this is a reflection of folding of the apo B molecule. The relative involvement of active and normal Lys in binding of apo B-100 to the LDL receptor on fibroblasts was explored by measuring the decrease in receptor binding as a function of the degree of methylation of the two types of Lys. Upper limits of 21 active and 31 normal Lys in the entire apo B-100 molecule are involved in the binding of LDL to the receptor. It is likely that these Lys are located in domains of apo B which contain clusters of basic amino acid residues and also bind heparin. If the sequence corresponding to apo B-48 (residues 1-2151) which does not bind to the receptor is excluded, then the above limits are halved; an upper limit of 10 active Lys may be particularly involved in receptor binding.

The surface chemistry of the wear scars formed on Cu‐3% Al alloy worn by a carburized steel ring have been studied by high‐resolution scanning Auger electron spectroscopy. A FALEX‐1 tester was used to perform the wear experiments. A number of conditions were studied including wear scars produced in an unlubricated air environment and wear scars produced using a 1% stearic acid dodecane lubricant. Iron was detected on the surface and in the near surface region of the lubricated and unlubricated specimens. Carbon and oxygen deposits a few tens of nanometers thick produced a mottled appearance on the lubricated wear scar. The iron transfer on the lubricated specimens was associated with the deposits, which were most likely a metallic soap. In addition to the iron, a larger concentration of aluminum was measured in the soap deposits. Iron was also detected on the dry wear scar. In this case, iron was not associated with any hydrocarbon deposits, but was randomly distributed throughout the wear scar. The iron concentration varied by more than an order of magnitude from one location to another and the iron Auger signal increased as the surface was removed by ion sputtering. The iron was probably in the form of very small particles incorporated into a Cu–Al ‘‘transfer layer.’’

ESCA, in combination with ion sputtering, was used to obtain compositional depth profiles of complex glasses which had been leached in DI water. The earliest and most obvious feature of aqueous attack was alkali depletion from the near surface regions of the glasses. Further corrosion was slowed by a surface buildup of various elements, which included aluminum, iron, nickel, titanium, zirconium, cerium, and neodymium. Elemental releases were calculated from the ESCA results, which were corrected for variations in the sputter rate through the reaction layer, and were compared to those measured directly by ICP solution analysis. The degree of agreement between the two methods was used to assess the importance of matrix dissolution in addition to selective component leaching in the aqueous corrosion of the glasses.

Thermolysis of 3,5,7-triphenyl-1,2(4H)-diazepine (1) gives, besides the known 2,4,6-triphenyl-pyridine (2), 3,5,6-triphenyl-1,2(4H)-diazepine (3) and 3,5,6-triphenyl-1,2(1H)-diazepine (4) whose structures are deduced on the basis of spectroscopic and chemical evidence. Neat thermolysis of 1 and the related 5-(p-methoxyphenyl)-3,7-diphenyl-1,2(4H)-diazepine (24a) and 5-(p-chlorophenyl)-3,7-diphenyl-1,2(4H)-diazepine (24c) gives only the corresponding pyridine derivatives 2, 26a, and 26c in low yields. Photolysis of 1 in ethanol affords the somewhat unstable 3,5,7-triphenyl-1,2-diazabicyclo[3.2.0]hepta-2,6-diene (21) which upon thermolysis undergoes cycloreversion to 1 and upon hydrolysis provides 3,5-diphenylpyrazole (23) and aceto-phenone. In contrast, photolysis of 1 as well as of 24a and 24c in acetone results in the formation of the pyridine (26a, 26c) and pyrazole (25a, 25c) derivatives respectively in low yields. Irradiation of 5-(P-dimethylaminophenyl)-3,7-diphenyl-1,2(4H)-diazepine (24d) under these conditions gives the photo-oxygenation product 24e. The observed thermolysis and photolysis results of 1 are compared and contrasted with those reported for the closely related 4,4-dimethyl-3,7-diphenyl-1,2(4H)-diazepine (16).

The photochemical behavior of a number of substituted derivatives of thiochroman-4-one 1-oxide has been examined. In contrast to the analogous sulfones these sulfoxides undergo a variety of photochemical rearrangements. At least three distinct pathways have been recognized; β-hydrogen abstraction or rearrangement to cyclic sulfenates, which then undergo further reaction by homolysis of the S—O bond, appearing to be particularly favorable processes. In a small number of examples, photochemical deoxygenation is observed as a competing reaction. Mechanisms which attempt to account for the influence of structural variations on the particular pathway followed have been proposed.

Extensive (d, t) and (d, Be) fast neutron sputtering results obtained by Batelle-Northwest are summarized for Nb and Au. The measured sputtering ratios are in the range of 10 −5 atoms/fast neutron. These results are compared to other available experimental results and to theoretical estimates. Some implications of fast neutron sputtering for future reactors are summarized.

Neutron sputtering yield measurements of niobium are reported for 14.8‐MeV (d,t) neutrons and for fast neutrons in the forward direction produced by 40‐MeV deuteron bombardment of a thick Be target. Six irradiations were performed with 23 niobium targets with a range of 1.7×1015 to 6.1×1016 (d,t) neutrons. One irradiation was performed with five niobium targets irradiated with a range of 4.7×1016 to 4.5×1017 (d,Be) neutrons. Sputtering targets included single crystals and annealed and cold‐worked material with various surface preparations. Target preparation overlapped or was identical, in several cases, to that used by another research group which has reported the observation of fast‐neutron‐induced ’’chunk’’ or micrometer particle emission. Several cm2 of collector which faced Nb targets irradiated to fluences of (0.4–1.1) ×1016 (d,t) neutrons/cm2 were carefully examined by scanning electron microscopy, but no evidence for neutron‐produced chunk emission ?0.5 μm was found. Thermal neutron activation ana...

Embrittlement of iron of variable impurity levels and identical thermal histories was shown to be dependent on the sulfur enrichment at grain interfaces and the applied cathodic potential. A fracture mode transition from transgranular ductile rupture to brittle intergranular failure was observed as a function of the grain boundary sulfur concentration. This mode change causes a dramatic loss in ductility at a threshold sulfur content of about 13% of monolayer on the fracture surface. A relationship is suggested between the roles S and H play in reducing boundary strength in iron.

A relationship between fracture mode, grain boundary composition, and hydrogen pressure has been determined for nickel straining electrode samples tested at cathodic potentials. This relationship can be expressed as C /SUB s/ ..cap alpha.. P /SUP -n/ /SUB H2/ where C /SUB s/ is the critical grain boundary sulfur concentration corresponding to 50 pct transgranular and 50 pct intergranular fracture and P /SUB H2/ is the hydrogen pressure. The value of n was found to be between 0.34 and 0.9. This expression was derived by relating C /SUB s/ to th hydrogen overpotential with the Nernst equation. At a cathodic test potential of -0.3 V (SCE). C /SUB s/ was equal to 0.20 monolayers of sulfur and at higher cathodic potentials or higher hydrogen pressures, C /SUB s/ decreased such that at -0.72 V (SCE) C /SUB s/ was equal to 0.045 monolayers of sulfur. The inverse hydrogen pressure dependence observed with cathodic hydrogen is similar to that for the hydrogen permeation rate or a critical hydrogen concentration derived by Gerberich et al. for gaseous hydrogen. This similarity between gaseous and cathodic hydrogen suggests that grain boundary impurities contribute to the hydrogen embrittlement process without altering the embrittlement process althoughmore » this result does not indicate whether decohesion or plasticity dependent processes are responsible for the combined sulfur-hydrogen effect on the intergranular fracture of nickel.« less

Neutron induced direct nuclear recoil sputtering ratios have been measured for a variety of 14.8 MeV (d, t) neutron induced reactions in Nb, Mo, V and 316 SS. Absolute recoil sputtering ratios for forward and backward sputtering are reported. Forward sputtering ratios are typically in the range of 10 −9 –10 −7 recoil atoms per (d, t) neutron while backward sputtering ratios are usually several orders of magnitude lower. Some of the implications of radioactive particle ejection in the first wall region of fusion reactors are discussed. It is shown that radioactivity ejected into the fusion reactor coolant channels by direct nuclear recoil and by lattice dynamic neutron sputtering, may have a significant effect on the design and maintenance of fusion reactors.

A simple procedure is outlined to obtain relative sensitivity curves that allow data collected on one Auger electron spectrometer to be related to data collected on a different spectrometer or to a standard data set. Data collected on three CMA systems demonstrate that dN/dE peak‐to‐peak amplitude ratios for pure elements can vary considerably but in a systematic manner for different systems. Such differences can be produced by variations in system design, by specimen or electron gun alignment, spectrometer contamination or other problems. However, if the differences in relative sensitivity are considered in the data analysis, data sets from different systems can be interrelated with reasonable accuracy.

A calculation has been made of the radionuclide product ejection from several elemental metal foils and a stain‐steel alloy foil from (n,x) reactions in a normally incident 14.8‐MeV neutron flux and compared with experimental data. The recoiling heavy products from the (n,x) reactions were assumed to propagate on the average in straight lines with a definite range‐vs‐energy relationship. With this assumption, for each distance x from the surface, an angle ϑcmc is found such that product nuclei at center‐of‐mass angles ϑcm

The effect on stress on the rate of H2S adsorption on iron has been examined using Auger Electron Spectroscopy (AES). A specially designed Ultra High Vacuum (UHV) straining stage allowed samples to be cleaned, aligned, strained, and dosed with H2S in front of the AES analyzer. An applied stress was observed to increase the H2S adsorption rate on annealed zone-refined iron by as much as 60 percent. This increase was observed in spite of the already high sticking coefficients reported for H2S adsorption on iron of 0.3 to 1.0. Stress-enhanced adsorption could be a factor for environmentally sensitive materials properties such as crack growth and stress corrosion. It was also observed that surface damage produced by ion sputtering also influenced the H2S adsorption rate and comparisons have been made between the effect of ion damage and stress on adsorption.

The addition of 0.06 monolayers of antimony to the grain boundaries of iron with 0.3 monolayers of sulfur was found to have no effect on the fracture toughness or subcritical crack growth behavior at cathodic potentials. Tests were conducted using compact tension type samples tested in 1N H2SO4 at cathodic potentials of −0.6V (SCE) to −1.25V (SCE). The absence of any effect of antimony on the fracture toughness was related to iron being in a “minimum” fracture toughness condition such that further segregation of an embrittling element had no effect. Also, the subcritical intergranular crack growth threshold was found to decrease with increasing cathodic potential consistent with results reported by others for transgranular fracture of steels in gaseous hydrogen.

Antimony, segregated to grain boundaries of iron, was found to be five times more effective than sulfur in promoting intergranular fracture of iron when tested in IN H2SO4 at cathodic potentials. A decrease in the ductility of iron accompanied the fracture mode change at increasing cathodic potentials. The effectiveness of antimony relative to sulfur was determined from straining electrode tests on iron and iron + 250 appm antimony alloys heat treated at 800 °C and 600 °C to produce different grain boundary chemical compositions. Grain boundary compositions were determined by Auger Electron Spectroscopy (AES). Similar grain boundary sulfur concentrations of 0.2 monolayers were observed by AES for the iron and iron + 250 appm antimony alloy after an anneal of 240 hours at 600 °C, while 0.08 monolayers of antimony was observed for the iron + 250 appm antimony alloy. These results suggest that sulfur and antimony do not compete for grain boundary sites.

Procedures are described for rapid, high yield chemical separation of niobium and vanadium from surfaces of quartz, silicon, and carbon following thermal neutron activation. Practical detection limits for stable niobium and vanadium are 7·1010 and 6·1011 atoms respectively. Application of these procedures to controlled thermonuclear reactor materials studies is discussed.

This paper presents the results of a round‐robin neutron‐sputtering experiment in which six independent research groups have participated. Targets of cold‐rolled niobium prepared by two standard techniques were used by all participants. Three participating groups used (d,t) neutrons of about 14.8 MeV, one group used (d,Be) neutrons produced by 40‐MeV deutrons on a thick Be target, and two groups used 16‐MeV protons in transmission. The emission of micrometer‐sized particles was observed by two groups and not observed by the other four. This particle emission was observed by two of the groups who used (d,t) neutrons in their irradiations. Chunk emission was observed for only one of the two standardized target types used in the round robin. The round‐robin results support the concept that the neutron‐sputtering yield of Nb, including atomic and chunk emission, has an estimated probable value no larger than 10−4 atoms per neutron. However, sputtering yields in the range 1.4×10−5 to ≲2.6×10−3 are reported here. The probable value for the sputtering yield was found to be independent of the two target preparations and the method of analysis, whether or not chunks were observed during analysis.

The percent intergranular fracture and tensile ductility of iron tested at cathodic potentials in IN H2SO4 was found to depend primarily on the grain boundary sulfur concentration. Zone refined and vacuum melted iron with different bulk sulfur, oxygen, and nitrogen but similar carbon concentrations were evaluated. The grain boundary chemistry was measured by Auger Electron Spectroscopy and the fracture mode and ductility by uniaxial straining electrode tests at potentials of -0.60 to -2.0 V (SCE) in IN H2SO4. The tensile ductility, as measured by the total strain and reduction of area, of both irons decreased with increasing cathodic potentials. The fracture mode and ductility at a potential of - 0.6 V (SCE) was related to the grain boundary sulfur concentration with increasing sulfur resulting in an increasing percent intergranular fracture and a decreasing ductility. The fracture mode and ductility was not related to the grain boundary oxygen, nitrogen or carbon concentrations but large bulk nitrogen concentrations did promote cleavage and quasicleavage fracture.

The effect of grain boundary chemistry on the tensile ductility and fracture mode of nickel at cathodic potentials was investigated in the present study. Recent work has shown that the fracture behavior and ductility of iron at cathodic potentials is dependent on the concentration of sulfur at grain interfaces. A threshold sulfur content was identified above which the fracture mode changed from transgranular ductile rupture to intergranular fracture. The existence of this transition in iron supplements the growing amount of evidence linking grain boundary chemistry and intergranular hydrogen embrittlement. Indications that a similar relationship might exist for nickel prompted the present research.

High‐energy neutrons such as those from the (d,t) reaction are capable of producing radioactive recoil particles which can be ejected from the surfaces of irradiated materials. We have made extensive measurements of such recoil emission probabilities with 14.8‐MeV (d,t) neutrons and some measurements with a 40‐MeV (d,Be) neutrons source. Recoil emission ratios are reported for targets of Nb, Mo, V, 316 SS, Fe, Ni, Cr, Ti, and Au which include 23 different fast‐neutron‐induced reactions. The total radioactive recoil sputtering ratio for each target range in magnitude from 3×10−8 to 3×10−7 recoil atoms/neutron for forward sputtering. Effective recoil atom ranges have been obtained from the experimental data and these are compared with theoretically calculated ranges. Various metallurgical preparations were used for the targets. Some implications of this radioactive recoil sputtering, regular neutron sputtering, and chemical corrosion to future controlled fusion machines are discussed. Neutron ejection of ra...

The surface composition and elemental depth profiles of native oxide films formed on amorphous FeCrNiPB alloys have been studied using both Auger electron spectroscopy (AES) and x‐ray photoelectron spectroscopy (XPS). Although both AES and XPS are surface sensitive techniques, differences in electron escape depths for various Auger and photoelectron peaks result in different sample volumes being analyzed by the two methods. This is found to be significant for specimens that have thin surface films with a varying elemental depth composition such as passive layers. Standard XPS and AES analysis of the data from the surface films using either published or bulk normalized sensitivity factors gave different results for the film composition from the two techniques. In addition, AES and XPS sputter profiles were dissimilar. A ’’true’’ depth profile was constructed using an iterative method, considering escape depth broadening effects and the measured profiles. Model calculations of XPS and AES film compositions ...

Specimens of Fe, Fe+1000 appm P and Fe+1000 appm P+800 appm Mn were evaluated. A grain boundary phosphorus concentration of 0.2 monolayers was insufficient to promote intergranular fracture. This is in contrast to the effect of sulfur where grain boundary concentraions exceeding 0.13 monolayers caused 100% fracture. Phosphorus competes with and reduces grain boundary sulfur segregation and has a beneficial effect on ductility. 10 refs.

The effectiveness of sulfur, phosphorus, and antimony in promoting the intergranular embrittlement of nickel was investigated using straining electrode tests in IN H2SO4 at cathodic potentials. Sulfur was found to be the critical grain boundary segregant due to its large enrichment at grain boundaries (104 to 105 times the bulk content) and the direct relationship between sulfur coverage and hydrogen-induced intergranular failure. Phosphorus was shown to be significantly less effective than sulfur or antimony in inducing the intergranular hydrogen embrittlement of nickel. The addition of phosphorus to nickel reduced the tendency for intergranular fracture and improved ductility because phosphorus segregated strongly to grain interfaces and limited sulfur enrichment. The hydrogen embrittling potency of antimony was also less than that of sulfur while its segregation propensity was considerably less. It was found that the effectiveness of segregated phosphorus and antimony in prompting intergranular embrittlementvs that of sulfur could be expressed in terms of an equivalent grain boundary sulfur coverage. The relative hydrogen embrittling potencies of sulfur, phosphorus, and antimony are discussed in reference to general mechanisms for the effect of impurity segregation on hydrogen-induced intergranular fracture.

The protonation of the 1,2(4H)-diazepines 2a, 2b, and the 1,2(1H)-diazepine 3a in various acidic media has been studied by u.v. and n.m.r. spectroscopy. Compounds 2a and 3a undergo protonation to give 4a and 7a, respectively, whereas 2b provides the monoprotonated species 4b in dilute acid and the diprotonated form 4c in strongly acidic solution. Spectral characteristics of crystalline 1,2(4H)-diazepinium perchlorates 4a, 4d, 7a, and 7c correlate well with those observed for the corresponding free bases in acidic solutions; 7a-ClO4 and 7c-ClO4 were obtained either from 2a and 2c or from 3a and 3c, respectively. In trifluoroacetic acid-d-D2O, deuterium exchange at C4 and C6 of 2a, 2b, and 3a was observed indicating the presence of small equilibrium concentrations of species 1a, 1c and/or 1d, and 1b under these conditions. Temperature variable n.m.r. spectroscopy provides evidence for ring inversion phenomena for the protonated forms 4a and 7a. In the case of 4a, the activation energy, ΔGc≠ = 10.2 ± 0.2 kcal/mol (Tc = 8 ± 3°) has been estimated. The difference in the activation energy between the free base and the protonated form, ΔG≠ (2a)—ΔG≠ (4a) = 6–7 kcal/mol is attributed to strong repulsive N1—N2 lone pair interaction in 2a in the transition state for the ring inversion process.Under vigorous acidic conditions, the 1, 2(4H)-diazepines 2a–c give pyrazoles (10a–c), pyridines (12a–c), and acetophenone. Using identical conditions, the 1,2(4H)-diazepinium salt, 7a-ClO4 provides pyrazole 11a and pyridine 12a and, in addition, the 1-methylaminopyridinium salt 13a. However, rearrangement also proceeds under very mild conditions (ethanol–water) as shown for 7a-ClO4 and 7c-ClO4 which yield compounds 11a and 12a, and 11c, 12c, and 13c, respectively. The 1, 2(1H)-diazepine 3a gives 11a, 12a, and 13a in ethanol–water solution and exclusively 13a in trifluoroacetic acid. The mechanism of these reactions is discussed in terms of formation of open-chain (15) and diaziridine-type (19) intermediates. Electrocylic mechanisms are eliminated from consideration on the basis of the absence of products 23, 24, and 25 which should have been observed from the reactions of 2b, 2c, and 7c-ClO4 if these pathways were operative.

The sub-critical intergranular crack growth behavior of iron and nickel showed several similarities and a few differences. The fracture thresholds and intergranular crack growth rates of iron and nickel were very similar which is consistent with the previously observed similarity of the effect of segregated sulfur and cathodic hydrogen on the fracture mode transition of these materials. The differences in their sub-critical crack growth behavior included the presence of a stage III crack growth regime in iron and its absence in nickel and the decrease in the fracture threshold of iron, K /SUB TH/, with increasing cathodic potential and the absence of a dependence of the K /SUB TH/ of nickel on cathodic potential. The present results were obtained with the same material used for the fracture mode transition tests but with compact tension (CT) samples in which the fracture mode was 100% intergranular for all cathodic potentials. Therefore, the present results represent the effect of cathodic potential on the intergranular crack growth rates of iron and nickel with large grain boundary sulfur concentrations (about 0.3 monolayers). The sub-critical crack growth behavior of iron and nickel with 0.3 monolayers of sulfur in their grain boundaries is similar. The fracture thresholdsmore » and Stage II crack growth rates are comparable; however, Stage III crack growth was observed in iron and not in nickel. The absence of Stage II crack growth in nickel was related to the large plastic zone size in nickel (about 47 mm) as compared to iron (about 2.6 mm).« less

X‐ray photoelectron spectroscopy was used to examine the composition and chemical state of anodically‐formed corrosion layers on FeNiCrPB amorphous alloys in a 1/2 M Na2SO4 solution with pH 5. Amorphous alloys are highly resistant to corrosion and particular attention was given to the chemical states of Cr and P, the elements known to play a major role in the corrosion resistance. A careful sample transfer procedure was established to minimize changes in the sample during transfer from solution to vacuum. A systematic and reproducible progression of chemical states was observed that was related to structure in the polarization curve and to elemental stability diagrams. The largest change in the P 2p oxidation state occurred between 0 and 700 mVSCE while the Cr2p3/2 oxidation state changed between 700 and 1150 mVSCE. Surface concentrations of P and Fe increased with increasing anodic potential, while concentrations of Ni, Cr, and B decreased.

Phosphorus bulk diffusion rates in one sputter-deposited and two liquid-quenched FeNi-based amorphous alloys were determined by measuring the kinetics of phosphorus segregation to a free surface. The diffusion rates for the three materials were found (1) to obey an Arrhenius relationship, (2) to be identical within experimental error and (3) to equal the rate of phosphorus diffusion in bulk iron. The average diffusion activation energy (approximately 1.85 eV atom −1 ) measured for these materials is different from the activation energies frequently obtained for stress relaxation and several other properties of the material, indicating that phosphorus diffusion is not the primary mechanism that controls these properties in the amorphous alloy.

The mass spectra of thiochromanone (I), isothiochromanone (II)-2-, 3- and 8-methylthiochromanone and the sulfoxides and sulfones derived from these cyclic sulfides have been determined and the major fragmentation routes established. For the iso series loss of SO or SO2 competes effectively with the retro-Diels-Alder reaction; however, for the thiochromanone derivatives the retro-Diels-Alder reaction is the major fragmentation route. There is no evidence for rearrangement of the sulfoxides or sulfones to sulfenates or sulfinates, respectively, prior to fragmentation.

We have previously described the inhibitory effect of interferon preparations on the multiplication of L1210 cells in vitro and presented the experimental results suggesting that interferon itself was the responsible factor (3, 4, 6) . This inhibition could be due to a decrease in the number of cells capable of dividing, to a prolongation of the cell generation time, to a decrease in the doubling potential of each cell between subcultivation and the stationary phase, or to a combination of these effects . We present here the results of experiments designed to test each of these possibilities by analyzing the effect of interferon on the division cycle of L1210 cells .

NMR spectroscopy of 13C-labeled human low density lipoprotein (LDL) has been employed to characterize the lysine (Lys) residues in apo B-100. Reductive methylation with [13C]formaldehyde converts up to two-thirds of the Lys to the dimethylamino derivative; this pool of Lys is exposed at the surface of the LDL particle. The [13C]dimethyl-Lys which are visualized exhibit resonances at chemical shifts of 42.8 and 43.2 ppm (pH 7.6) indicating that they exist in two different microenvironments; this is a reflection of the native conformation of apo B associated with lipid, because the labeled, reduced, and alkylated protein gives a single resonance when dissolved in 7 M guanidine hydrochloride. The pH dependences of the Lys chemical shifts indicate that the two types of Lys titrate with different pK values; "active" Lys have a pK of 8.9, while "normal" Lys have a pK of 10.5. About 53 active Lys and 172 normal Lys are exposed on the surface of LDL with the remaining 132 Lys which are present in the human apo B-100 molecule being buried and unavailable for methylation. Addition of paramagnetic ions indicates that the active and normal Lys have different exposures to the aqueous phase; apparently this is a reflection of folding of the apo B molecule. The relative involvement of active and normal Lys in binding of apo B-100 to the LDL receptor on fibroblasts was explored by measuring the decrease in receptor binding as a function of the degree of methylation of the two types of Lys. Upper limits of 21 active and 31 normal Lys in the entire apo B-100 molecule are involved in the binding of LDL to the receptor. It is likely that these Lys are located in domains of apo B which contain clusters of basic amino acid residues and also bind heparin. If the sequence corresponding to apo B-48 (residues 1-2151) which does not bind to the receptor is excluded, then the above limits are halved; an upper limit of 10 active Lys may be particularly involved in receptor binding.