172,530 research outputs found
Effects of chitosan treatment on avocado postharvest diseases and expression of phenylalanine ammonia-lyase, chitinase and lipoxygenase genes
No full textStem-end rot (Lasiodiplodia theobromae) and anthracnose (Colletotrichum gloeosporioides) are major postharvest diseases in avocado that cause severe postharvest losses throughout the supply chain. One of the strategies to reduce development of such decay agents resides in the application of resistance inducers (e.g. chitosan), capable of reducing fungal growth and inducing resistance in fruit tissues. The influence of chitosan treatment (1% or 1.5% w/v) was investigated on decay incidence, gene expression of phenylalanine ammonia-lyase (PAL), chitinase (CHI) and lipoxygenase (LOX) and antioxidant enzyme activity [superoxide dismutase (SOD) and catalase (CAT)] in i) drop-inoculated (without wounding) or ii) artificially infected (with wounding) avocado (cv. ‘Hass’) with L. theobromae or C. gloeosporioides pathogens and also in iii) naturally infected (natural inoculum) avocado. Fruit were dipped in 1% or 1.5% w/v chitosan dissolved in water for 3 min, followed by storage for 14 d and 28 d respectively at 7.5 °C, and thereafter for 5 d at 18 °C to simulate market shelf conditions. Chitosan at 1.5% significantly reduced the incidence of stem-end rot and anthracnose in both inoculated and naturally infected avocados. The up-regulation of PAL and down-regulation of LOX genes moderately allowed higher epicatechin contents (90 mg kg−1 FW) in the exocarp, which could have contributed to improved anthracnose control. The up-regulation of CHI genes and higher SOD activity could have contributed to control of stem-end rot. Chitosan solution (1.5%) retained moderate levels of C7 sugars and firmness up to 5 d shelf life. The control of stem-end rot and anthracnose of avocados obtained with 1.5% chitosan can be ascribed to a combination of its antifungal and eliciting properties
Comment on a paper by Rindani and Sivakumar
No full textIn a recent work Rindani and Sivakumar claim to have found a new spin-3/2 theory with novel properties. It is shown here that the system which they consider is equivalent to the conventional Rarita-Schwinger equation. Their approach therefore appears unlikely to succeed in eliminating any of the long-standing problems associated with the interacting spin-3/2 field
On inverse-positivity of sub-direct sums of matrices
No full text<p>Slides from 18th Conference of the International Linear Algebra Society (ILAS), held in Providence, Rhode Island, USA on June 3-7, 2013.</p>
<p>These slides augment the paper:</p>
<p>Shani Jose and K. C. Sivakumar. <strong>On inverse-positivity of sub-direct sums of matrices</strong>. Linear Algebra and its Applications, Volume 439, Number 6, pp. 1670-1677, 2013.</p
Moore-Penrose inverses of perturbed operators on Hilbert spaces
No full text<p>Slides from Prairie Analysis Seminar 2013, held in Department of Mathematics, Kansas State University<br>Manhattan, KS, USA on September 27-28, 2013.</p>
<p>These slides augment the paper:</p>
<p>Shani Jose and K. C. Sivakumar. <strong>On nonnegative Moore-Penrose inverses of perturbed matrices</strong>. J. Appl. Math., (2013), Article ID 680975, 7 pages.</p
Novel Pt-Ru nanoparticles formed by vapour deposition as efficient electrocatalyst for methanol oxidation, Part II. Electrocatalytic activity
No full textThe methods developed and described in paper–part I are employed to prepare nanometer size Pt-Ru particles on a Vulcan XC72R substrate with controlled metal loading. Transmission Electron Microscopy (TEM) confirmed uniform particles size (average diameter 2nm) and homogeneous dispersion of the particles over the substrate. Energy Dispersive X-ray absorption (EDX) analysis confirmed the compositional homogeneity. The catalytic activity of these supported nanoparticles with regard to methanol electrooxidation is investigated using cyclic voltammetry (CV), chronoamperometry (CA) and CO-stripping voltammetry techniques at temperatures between 25°C and 60°C. Such investigation concerns supported catalysts prepared with c.a. 10 and 18 wt% overall metal loading (Pt + Ru) onto the Vulcan XC72R substrate. Comparative testing of our catalysts and a commercial Pt-Ru/Vulcan reveals markedly superior activity for our catalysts. In fact, we observe for the latter a five-fold increase of the oxidation current as compared to a commercial Pt-Ru/Vulcan with equal metal loading. One of the reasons for the greater activity is found to be the very high dispersion of the metals over the substrate, i.e. the large surface area of the active phase. Other reasons are plausibly ascribable to the varied Pt/Ru composition and/or reduced presence of contaminants at the catalyst surface
An additional record of Fejervarya manoharani Garg and Biju from the Western Ghats with a description of its complete mitochondrial genome
No full textKiran, S. Kumar, Anoop, V. S., Sivakumar, K. C., Dinesh, Raghunathan, Mano, J. P., Kaushik, Deuti, Sanil, George (2017): An additional record of Fejervarya manoharani Garg and Biju from the Western Ghats with a description of its complete mitochondrial genome. Zootaxa 4277 (4): 491-502, DOI: https://doi.org/10.11646/zootaxa.4277.4.
Effect of third metal on the electrocatalytic activity of PtRu/Vulcan for methanol electrooxidation
No full textThe effect of a third metal on the activity of PtRu/Vulcan towards methanol oxidation reaction (MOR) is studied. An efficient method to prepare ternary catalysts was used, which allows the introduction of the third metal to PtRu/Vulcan without altering its particle size or dispersion. Ni, Mo, Co, and Ir were chosen and added to PtRu/Vulcan, based on theoretical and experimental literature results, anticipating enhancement in the catalytic activity of PtRu/Vulcan. The composition of the third metal can be varied from trace to considerable amounts. TEM and EDX analysis were used to determine the particle size, dispersion and the composition of the ternary catalysts. Cylic voltammetry, chronoamperometry and CO-stripping voltammetry were used to analyze and compare the activities of the catalysts at 25°C. It has been found that addition of even trace amounts of third metal significantly affects the catalytic activity of PtRu towards MOR
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Macrochlamys leggeae Chandra & Sivakumar 2019, sp. nov.
No full textMacrochlamys leggeae sp. nov. (Figures 2 aı 3a – bı 4a – b; Table 1) Type material Holotype: 1 ex. (SL 10.28 mmı SW 7.08 mm) (NZSI M.31208/8)ı 300 m north-east of the Pushpawati River (30.72573°Nı 079.59150°E) 3544 mı Chamoli Districtı Uttarakhandı Western Himalayaı India; coll. S.K. Sajanı 28 August 2016. Paratypes: 4 ex. dry/ 7 ex. wet (NZSI M.31209/8)ı 300 m north-east of the Pushpawati River (30.72573° Nı 079.59150°E) 3544 mı Chamoli Districtı Uttarakhandı Western Himalayaı India (Figure 5)ı 5 ex. (NZSI MO.147)ı 300 m north-east of the Pushpawati River (30.72573° Nı 079.59150°E) 3544 mı Chamoli Districtı Uttarakhandı Western Himalayaı India deposited at Northern Regional Centreı Zoological Survey of Indiaı Dehradunı Uttarakhandı India; 2 ex. (NZSI M.316 – 319) 300 m north-east of the Pushpawati River (30.72573° Nı 079.59150°E) 3544 mı Chamoli Districtı Uttarakhandı Western Himalayaı India deposited at High Altitude Regional Centreı Zoological Survey of Indiaı Solanı Himachal Pradeshı Indiaı same date as holotype. Diagnosis The new species Macrochlamys leggeae has the following combination of characters: spire height is lowı the body whorl globose and largeı aperture width is greater than heightı lower whorl countı embryonic shell largerı smooth radial stair in protochonch and external shell surfaceı fewer teeth in each rowı penis very small (Figures 2 aı 3a – bı 4a – bı 7a – gı 8; Tables 1 – 2). Description The shell is medium (SL 8.66 – 10.28 mm)ı thin and smoothı convex and sub-globosely depressed; apex is obtuse and depressedı shell surface has smooth lirae over the whole bodyı shell pale in colour and horny; body whorl broad and globsely rounded at periphery and whorl largeı about two-thirds of shell height and convexı slightly descending in frontı spire is low (SH 1.16 ± 0.01 mm); whorls 4 ¼ – 5; peristome simple and thinı aperture is broadly ovate-lunate in shape; howeverı the width of the aperture is greater than its height (AH 4.76 ± 0.28 mm and AW 5.02 ± 0.33 mm)ı columellar region is straight and reflected at the perforationı umbilicus of shell narrowly perforate. Radula Each row of the radula consists of 73 teeth with the formula 22-1-13-1-13-1-22 (36-1-36). Central tooth (c) triangular tricuspid with large mesoconus (m). Lateral teeth (lt) asymmetric tricuspid with very small ectoconus (ec) and larger endoconus (et). Rachidian tooth central cusp base width 10.19 µm and rachidian tooth central cusp height 29.49 µm (Figure 7a – g). Genital organ Atrium (at) very shortı penis (p) short and cylindrical and corresponding to penial verge (pv)ı length of penis 1.20 mmı epiphallus (e) long and slender tubeı double length of penisı epiphallic caecum (epc) having one coiled circle located at middle of epiphallus and attached with penial retractor muscle (prm). Flagellum (fl) slightly larger then penis lengthı with single fold. Vas deferens (vd) thin slender tube connected between distal end of epiphallus and free oviduct (fo). Vagina (v) smaller than penis in length (0.8 mm) and cylindrical in shape. Dart apparatus (da) 4 times as long as penisı stout and cylindrical in shape and attached to proximal end of vaginaı tip of da attached with dart retractor muscle (drm). Gametolytic sac (gs) prolonged and bulbousı around 1 mm in diameter. Gametolytic duct (gd) long (double penis length)ı stout and cylindrical in shapeı free oviduct (fo) as long as penis and a cylindrical tube. Oviduct (ov) with large lobulesı with prostate gland (pg) running alongside. Hermaphrodite duct (hd) coiled and approximately 5 mm in length (Figure 8). External features Animal about 4 – 5 mm in length with reticulated skinı the shell is pale yellowı with a large and globose body whorl. The body surface is dark chocolate brown in colourı while the tentacle is darker. The caudal horn is raised and same colour as the body. The posterior left dorsal lobe is short and slightly visible. The animal secretes a very light slime during locomotion. Distribution. The specimens were collected from 300 m north-east of the Pushpawati River (30.72573°Nı 079.59150°E) 3544 mı Chamoli Districtı Uttarakhandı Western Himalayaı India (Figures 4c – fı 5). Habitat. The new species was usually found more than 3500 m above sea level on the ground surface and on small bushes (vegetation) of Meconopsis aculeata and Aconitum sp. in the sub-alpine zone of the main valley. This species is probably endemic to this particular region and known only from the type locality (Figure 5). The species is mostly active during the monsoon and post-monsoon season. Etymology. The specific epithet ‘leggeae’ is named after Joan Margaret Leggeı Botanist of the Royal Botanical Gardensı Kewı who came to India to study flora of the Valley of Flowersı and lost her life there on 4 July 1939. Remarks. The new species M. leggeae sp. nov. is compared with M. nuda (Pfeifferı 1852) (Figure 2e). In M. nuda the shell is thickı larger and less globose and the spire is highı and the aperture is shortı while in the new species the shell is thin and sub-globoseı and the aperture is wider than long. Howeverı the height of the body whorl is greater than in M. nuda and the number of whorls is also fewer (4 ¼ – 5)ı whereas in M. nuda the whorl number is 5 – 5 ½. In M. vesicula (Bensonı 1838) the shell is larger in size (SL 13.05 ± 1.38 mm)ı whereas the ratio of the aperture height to shell height is also greater (4.48 mm). In M. glauca (Pfeifferı 1846) the shell is also large in size (SL 16.64 ± 3 mm)ı and the height to width ratio of the aperture is also less (0.93 mm) than in M. leggeae (0.95 mm). In comparison to M. kuluensis Blanfordı 1904 the shell length and width are also greater (SL 11.28 ± 2.02 mmı SW 8.41 ± 1.49 mm)ı and the aperture ratio is greater than in M. leggeae. In M. leggeae the diameter of the spire without the last whorl is also less than in all the compared species (4.80 ± 0.28 mm) (see Tables 1 and 2; Figure 2b – d). The unique large body whorlı aperture openingı and morphometric measurements are reliable characters to distinguish the species. Statistical species differentiation. For morphometric differentiation among five individuals of Macrochlamys leggeae sp. nov. (paratype NZSI M.31ı209/8ı n = 5) and five individuals each of the congeneric species M. vesicula ı M. glauca ı M. kuluensis and M. nuda (n = 5)ı a PCA was performedı using Past3. The variables SL/SW – shell length/shell widthı AH/AW – aperture height/aperture widthı AW/SH – aperture width/spire heightı HBW/AH – height of the body whorl/aperture heightı and HBW/SH – height of the body whorl/spire height were calculated. PC1 explained 93.7% of the total variance and PC2 explained 5% of the variance in th eshell ratio (Figure 6). The most significant variance was observed in the ratios AW/SH (0.822) and HBW/SH (0.567) which are significantly different from those of the closely related species (Tables 1 and 3; Figure 6). (Continued) (Continued)Published as part of Sajan, Sheikh, Basudev Tripathy, Chandra, Kailash & Sivakumar, Kuppusamy, 2019, A new species of the genus Macrochlamys Grayı 1847 (Stylommatophora: Ariophantidae) from Western Himalayaı India, pp. 797-813 in Journal of Natural History 53 (13) on pages 800-808, DOI: 10.1080/00222933.2019.1615566, http://zenodo.org/record/367562
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
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