Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 17 de 17
Filter
Add more filters










Publication year range
1.
Zootaxa ; 5094(4): 501-552, 2022 Feb 08.
Article in English | MEDLINE | ID: mdl-35391437

ABSTRACT

The Zoological Survey of India, Western Regional Centre, Pune (ZSI-WRC) contains 1887 specimens of mostly unstudied marine brachyuran crabs. The present systematic study on the marine crabs of ZSI-WRC reports 62 species in 44 genera, 18 families and nine superfamilies. Of these, four genera and 13 species are new distributional records within India. We also record three species for the first time from the Indian waters: Metopograpsus cannicci Innocenti, Schubart Fratini, 2020 (Grapsidae MacLeay, 1838), Varuna yui Hwang Takeda, 1986 (Varunidae H. Milne Edwards, 1853), and Ilyograpsus paludicola (Rathbun, 1909) (Macrophthalmidae Dana, 1851). The record of Varuna yui is significant as it is the first time it has been found from the western Indian Ocean. The subfamily Ilyograpsinae tevi, 2005, has likewise not previously been reported from India. The taxonomy of the poorly known menippid crab, Sphaerozius scaber (Fabricius, 1798), is clarified with the designation of a lectotype, and its taxonomy is discussed. Sphaerozius scaber can be distinguished from the only congener S. nitidus Stimpson, 1858, by its prominently tuberculated carapace, palm and carpus of the chelipeds, and the strongly curved male first gonopod, with the distal part gently tapering into a truncate tip. Sphaerozius scaber is a new addition to the west coast of India. With the inclusion of the present new records, India is now known to have 939 species of marine brachyuran crabs in 375 genera of 63 families.


Subject(s)
Brachyura , Lice Infestations , Animal Shells , Animals , Humans , India , Male
2.
Zootaxa ; 4674(2): zootaxa.4674.2.2, 2019 Sep 24.
Article in English | MEDLINE | ID: mdl-31716010

ABSTRACT

A new species of the hitherto monotypic gecarcinucid freshwater crab genus, Arcithelphusa Pati Sudha Devi, 2015, is described from the Western Ghats, in the Wayanad district of Kerala, India. Arcithelphusa tumpikkai sp. nov. can be easily distinguished from the only congener, A. cochleariformis Pati Sudha Devi, 2015, mainly by its relatively broader carapace, the presence of a short flagellum on the exopod of the third maxilliped, and the relatively less stout male first gonopod, with a sharply bent and relatively long terminal segment. The diagnosis for Arcithelphusa is emended to include the new species, which can be useful in distinguishing it from the closely related genus Cylindrotelphusa Alcock, 1909. The state of Kerala now has 38 species of gecarcinucid crabs, including the present new species.


Subject(s)
Brachyura , Decapoda , Lice Infestations , Animals , Fresh Water , India , Male
3.
Zootaxa ; 4440(1): 1-73, 2018 Jun 25.
Article in English | MEDLINE | ID: mdl-30313127

ABSTRACT

The taxonomy of three morphologically related and endemic genera of the northern Western Ghats (Ghatiana Pati Sharma, 2014, Gubernatoriana Bott, 1970, and Inglethelphusa Bott, 1970) is re-assessed to accommodate several new taxa. We describe a new genus, Sahyadriana gen. nov. and its five new species [S. billyarjani sp. nov., S. pachyphallus sp. nov., S. sahyadriensis sp. nov. (type species), S. tenuiphallus sp. nov., and S. woodmasoni sp. nov.]. Additionally, three new species each of Ghatiana (Gh. botti sp. nov., Gh. pulchra sp. nov., and Gh. rathbunae sp. nov.) and Gubernatoriana (Gu. longipes sp. nov., Gu. marleshwarensis sp. nov., and Gu. wallacei sp. nov.) are described. Five species previously in Gubernatoriana are now transferred to Sahyadriana gen. nov., viz. S. alcocki (Pati in Pati, Thackeray Khaire, 2016) comb. nov., S. pilosipes (Alcock, 1909) comb. nov., S. thackerayi (Pati in Pati, Thackeray Khaire, 2016) comb. nov., S. triangulus (Pati Sharma, 2014) comb. nov., and S. waghi (Pati in Pati, Thackeray Khaire, 2016) comb. nov. Gubernatoriana basalticola Klaus, Fernandez Yeo, 2014, is transferred to Ghatiana. Inglethelphusa is still proved to be monotypic. Consequently, Ghatiana now contains eight species, three of which are new; Gubernatoriana, four species, including three new species; Inglethelphusa, one species; and Sahyadriana gen. nov., ten species, including five new species. Sahyadriana pilosipes is rediscovered more than a century after its description. All these genera can be separated from other Indian gecarcinucid crabs by the absence of a flagellum on the exopod of the third maxilliped and a very short G2. The relevant identification keys are revised. Currently, 120 species of freshwater crabs under 35 genera and two families are found in India. Kerala is the most species-rich (35 species) state in India followed by Maharashtra (29 species) and Assam (21 species). The Western Ghats of India now includes 17 genera and 58 species of gecarcinucid crabs. A checklist and distribution of Indian freshwater crabs is provided.


Subject(s)
Brachyura , Decapoda , Animals , Fresh Water , India , Lice Infestations
4.
RSC Adv ; 8(52): 30021-30039, 2018 Aug 20.
Article in English | MEDLINE | ID: mdl-35547290

ABSTRACT

The dynamic disorder and electric field effects on charge transport in triphenylamine-benzimidazole based molecular solids have been investigated using electronic structure calculations, molecular dynamics and Monte-Carlo simulations. During the charge propagation, the energy loss of the carrier in each hopping step is monitored by Monte-Carlo simulation. We derive a survival probability correlated momentum-energy distribution for drift-diffusion analysis and we demonstrate the dispersion initiated charge trapping mechanism which is indeed ideal for light emission efficiency via recombination. In the present model, the proposed carrier drift energy-current density expression and Shockley diode current density equation are used to study the current density-voltage characteristics; accordingly the ideality factor (∼1.8-2.0) dictates the deviation of Einstein's classical diffusion-mobility relation (where the ideality factor is unity). The dual mechanism of electric field assisted site energy gap on coherent-like transport and the electric field stretched dispersion on recombination are observed in tris(3'-(1-phenyl-1H-benzimidazole-2-yl)biphenyl-4-yl)amine (TBBI) and tris(4'-(1-phenyl-1H-benzimidazole-2-yl)biphenyl-4-yl)amine (TIBN) molecular systems, which can be used as host materials in organic light emitting diodes (OLEDs). We find the transport going from coherent to incoherent, due to the conversion mechanism of dynamic to static disorder. This can also be a controlled by applied electric field. By adjusting the applied electric field, film thickness and changing the π-stacked molecular aggregation via substitutions, one can fix the dispersive parameter and accordingly calculate the charge transport properties to design efficient host-materials for photovoltaic and light emitting diode devices.

5.
Zootaxa ; 4237(1): zootaxa.4237.1.11, 2017 Feb 26.
Article in English | MEDLINE | ID: mdl-28264310

ABSTRACT

A new species of potamid freshwater crab, Himalayapotamon garhwalense n. sp., is described from a stream near Khanda in Pauri Garhwal district of Uttarakhand, India. The new species is differentiated from all congeners by a suite of carapace and gonopod features, including the short, stout and conical G1 terminal joint with gradually tapered distal portion. Himalayapotamon Pretzmann, 1966, is now represented by 11 species including H. garhwalense n. sp. An identification key to the species in the genus is provided.


Subject(s)
Brachyura , Animals , Fresh Water , India
6.
ACS Appl Mater Interfaces ; 9(12): 10664-10672, 2017 Mar 29.
Article in English | MEDLINE | ID: mdl-28267317

ABSTRACT

Generation of hydrogen by photochemical, electrochemical, and other means is a vital area of research today, and a variety of materials have been explored as catalysts for this purpose. C3N4, MoS2, and nitrogenated RGO (NRGO) are some of the important catalytic materials investigated for the hydrogen evolution reaction (HER) reaction, but the observed catalytic activities are somewhat marginal. Prompted by preliminary reports that covalent cross-linking of 2D materials to generate heteroassemblies or nanocomposites may have beneficial effect on the catalytic activity, we have synthesized nanocomposites wherein C3N4 is covalently bonded to MoS2 or NRGO nanosheets. The photochemical HER activity of the C3N4-MoS2 nanocomposite is found to be remarkable with an activity of 12778 µmol h-1 g-1 and a turnover frequency of 2.35 h-1. The physical mixture of C3N4 and MoS2, on the other hand, does not exhibit notable catalytic activity. Encouraged by this result, we have studied electrochemical HER activity of these composites as well. C3N4-MoS2 shows superior activity relative to a physical mixture of MoS2 and C3N4. Density functional theory calculations have been carried out to understand the HER activity of the nanocomposites. Charge-transfer between the components and greater planarity of cross-linked layers are important causes of the superior catalytic activity of the nanocomposites. Covalent linking of such 2D materials appears to be a worthwhile strategy for catalysis and other applications.

7.
Phys Chem Chem Phys ; 18(40): 28198-28208, 2016 Oct 12.
Article in English | MEDLINE | ID: mdl-27722590

ABSTRACT

We present a theoretical investigation of small aggregates of quadrupolar (A-π-D-π-A or D-π-A-π-D) charge-transfer dyes, with attention focused on the role of intermolecular interactions in determining their optical properties. We tackle the theoretical issue by adopting essential-state models (ESMs), which describe an isolated molecule in terms of a minimal number of electronic states, corresponding to the resonance structures. ESMs quite naturally describe intermolecular interactions relaxing the dipolar approximation and accounting for molecular polarizabilities. The approach is applied to curcuminoid and squaraine dyes, two families of chromophores with weak and strong quadrupolar character, respectively. The method is validated against experiment and for curcuminoids also against time-dependent density functional theory. ESMs rationalize the strong ultra-excitonic effects recurrently observed in the experimental optical spectra of aggregates of highly polarizable quadrupolar dyes, offering a valuable tool to exploit the supramolecular design of material properties.

8.
Zootaxa ; 4083(4): 569-86, 2016 Feb 23.
Article in English | MEDLINE | ID: mdl-27394247

ABSTRACT

Five new species of gecarcinucid freshwater crabs, Ghatiana atropurpurea n. sp., Ghatiana splendida n. sp., Gubernatoriana alcocki Pati n. sp., Gubernatoriana thackerayi Pati n. sp., and Gubernatoriana waghi Pati n. sp. are described from the Western Ghats in Maharashtra and Goa states of India. Ghatiana atropurpurea n. sp. can be differentiated from other species of Ghatiana Pati & Sharma, 2014 by the shape and colour of its carapace, and the sigmoid-shaped male first pleopod (G1). Ghatiana splendida n. sp. is separated from its congeners mainly by its long anterolateral margin of the carapace and short terminal article of the G1. Besides, the colour pattern (deep pink carapace and chelipeds, orange ambulatory legs) of G. splendida n. sp. is exceptional among its congeners. Gubernatoriana alcocki n. sp. is unique among species of Gubernatoriana Bott, 1970 due to its inwardly curved tip of the terminal article of the G1. The stout and cone-shaped terminal article of the G1 of G. thackerayi n. sp. is characteristic among its congeners. In addition, G. thackerayi n. sp. has a unique colouration amongst congeners (violet-red carapace and ambulatory legs, orange-red chelipeds). Gubernatoriana waghi n. sp. can be distinguished from its congeners by the quadrate-shaped carapace, narrow frontal margin, pointed tips of the cheliped fingers, short terminal article of the G1 and very short or vestigial terminal article of the male second pleopod (G2). The body colour (burnt orange carapace and ivory coloured chelipeds and ambulatory legs) of G. waghi n. sp. is also important to distinguish live crabs of the genus. Key to the species of Ghatiana and Gubernatoriana is provided.


Subject(s)
Brachyura/classification , Animal Distribution , Animal Structures/anatomy & histology , Animal Structures/growth & development , Animals , Body Size , Brachyura/anatomy & histology , Brachyura/growth & development , Ecosystem , Female , India , Male , Organ Size
9.
Zootaxa ; 3963(3): 416-24, 2015 May 27.
Article in English | MEDLINE | ID: mdl-26249406

ABSTRACT

A new species of freshwater crab, Spiralothelphusa gibberosa n. sp. is described from rice fields near Kizhoor in Thrissur district of Kerala in southern India. The new species is easily differentiated from its congeners by its first male pleopod (G1), which has a long, less strongly twisted terminal segment and distal portion of subterminal segment in addition to a setose hump on the outer margin of the non-twisted portion. Key to the species of the genus Spiralothelphusa Bott, 1968, is provided. We recognized S. wuellerstorfi (Heller, 1862), as a new record to Maharashtra based on specimens wrongly identified as S. hydrodroma (Herbst, 1794), by Pati & Sharma (2014).


Subject(s)
Brachyura/classification , Animal Distribution , Animal Structures/anatomy & histology , Animal Structures/growth & development , Animals , Body Size , Brachyura/anatomy & histology , Brachyura/growth & development , Ecosystem , Female , India , Male , Organ Size
10.
Indian J Med Microbiol ; 33 Suppl: 15-9, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25657137

ABSTRACT

PURPOSE: Human cytomegalovirus (HCMV) is the commonest pathogen causing congenital infection globally. The diagnosis of congenital infection is based either on viral isolation (in cell culture) or demonstration of HCMV DNA from the urine. Saliva is also being used as an alternative sample to urine for the same. The objective of this study was to compare the following assays-polymerase chain reaction (PCR) from urine, saliva and blood, serology (anti-HCMV IgM) and antigen detection (HCMV pp65 antigenaemia) for the diagnosis of congenital HCMV infection. MATERIALS AND METHODS: Urine and blood samples were collected from 31 infants (median age: 13 weeks) with suspected HCMV infection. For 18 infants, additional saliva samples were collected and all the above assays were compared. RESULTS: PCR for HCMV DNA from urine and anti-HCMV IgM were performed for all 31 infants. Of these, 22 (70.9%) were positive for both assays. In 18 (of the 22) infants positive by both assays, PCR for HCMV DNA from saliva was positive in all 18 (100%), PCR from blood in 7/18 (38.8%) and HCMV pp65 antigenaemia only in 1/18 (5.5%) of the infants. CONCLUSION: Detection of HCMV DNA in urine combined with anti-HCMV IgM are suitable assays to diagnose HCMV infection in infants. Both PCR from the blood and HCMV pp65 antigenaemia lack sensitivity in infants. Salivary PCR combines convenience with high sensitivity and can substitute PCR from urine, especially in the outpatient and field settings. To the best of our knowledge, this is the first study from India to evaluate salivary PCR for the diagnosis of congenital HCMV infection.


Subject(s)
Cytomegalovirus Infections/congenital , Cytomegalovirus Infections/diagnosis , Cytomegalovirus/genetics , Cytomegalovirus/immunology , Enzyme-Linked Immunosorbent Assay , Polymerase Chain Reaction , Antibodies, Viral/immunology , Antigens, Viral/blood , Antigens, Viral/immunology , DNA, Viral , Enzyme-Linked Immunosorbent Assay/methods , Female , Humans , Infant , Infant, Newborn , Male , Polymerase Chain Reaction/methods
11.
Clin Infect Dis ; 58(10): 1467-72, 2014 May.
Article in English | MEDLINE | ID: mdl-24567248

ABSTRACT

BACKGROUND: A high rate of congenital cytomegalovirus (CMV) has been documented in human immunodeficiency virus (HIV)-exposed infants in industrialized settings, both in the pre- and post-highly active antiretroviral therapy (HAART) era. Only limited data on the birth prevalence of congenital CMV among infants of HIV-infected women on prenatal antiretroviral (ARV) prophylaxis are available from sub-Saharan Africa, despite a high prevalence of both infections. We evaluated the prevalence of congenital CMV in HIV-exposed infants in the Western Cape, South Africa. METHODS: HIV-infected mothers were recruited in the immediate postnatal period at a referral maternity hospital between April and October 2012. Maternal and infant clinical data and newborn saliva swabs were collected. Saliva swabs were assayed by real-time polymerase chain reaction for CMV. Data were analyzed using univariate and multivariate logistic regression analyses to determine specific demographic, maternal, and newborn characteristics associated with congenital CMV. RESULTS: CMV was detected in 22 of 748 newborn saliva swabs (2.9%; 95% confidence interval [CI], 1.9%-4.4%). Overall, 96% of mothers used prenatal ARV prophylaxis (prenatal zidovudine, 43.9%; HAART, 52.1%). Maternal age, gestational age, prematurity (<37 weeks' gestation), type of ARV prophylaxis, length of ARV prophylaxis, birth weight, small for gestational age, and infant feeding choice were not significantly different between CMV-infected and -uninfected infants. Maternal CD4 count <200 cells/µL during pregnancy was independently associated with congenital CMV (adjusted odds ratio, 2.9; 95% CI, 1.2-7.3). A negative correlation between CMV load in saliva and maternal CD4 count was observed (r = -0.495, n = 22, P = .019). CONCLUSIONS: The birth prevalence of congenital CMV was high despite prenatal ARV prophylaxis, and was associated with advanced maternal immunosuppression.


Subject(s)
Anti-HIV Agents/therapeutic use , Cytomegalovirus Infections/congenital , Cytomegalovirus Infections/epidemiology , HIV Infections/drug therapy , Pregnancy Complications, Infectious/drug therapy , AIDS-Related Opportunistic Infections , Adult , Antiretroviral Therapy, Highly Active , Cytomegalovirus/isolation & purification , Cytomegalovirus Infections/transmission , Cytomegalovirus Infections/virology , Female , HIV Infections/prevention & control , Humans , Infant , Infant, Newborn , Infectious Disease Transmission, Vertical , Nevirapine/therapeutic use , Pregnancy , Prevalence , South Africa/epidemiology , Viral Load , Zidovudine/therapeutic use
12.
Phys Chem Chem Phys ; 13(28): 12734-44, 2011 Jul 28.
Article in English | MEDLINE | ID: mdl-21677974

ABSTRACT

Resonance Energy Transfer (RET) is investigated in pairs of charge-transfer (CT) chromophores. CT chromophores are an interesting class of π conjugated chromophores decorated with one or more electron-donor and acceptor groups in polar (D-π-A), quadrupolar (D-π-A-π-D or A-π-D-π-A) or octupolar (D(-π-A)(3) or A(-π-D)(3)) structures. Essential-state models accurately describe low-energy linear and nonlinear spectra of CT-chromophores and proved very useful to describe spectroscopic effects of electrostatic interchromophore interactions in multichromophoric assemblies. Here we apply the same approach to describe RET between CT-chromophores. The results are quantitatively validated by an extensive comparison with time-dependent density functional theory (TDDFT) calculations, confirming that essential-state models offer a simple and reliable approach for the calculation of electrostatic interchromophore interactions. This is an important result since it sets the basis for more refined treatments of RET: essential-state models are in fact easily extended to account for molecular vibrations in truly non-adiabatic approaches and to account for inhomogeneous broadening effects due to polar solvation. Optically forbidden (dark) states of quadrupolar and octupolar chromophores offer an interesting opportunity to verify the reliability of the dipolar approximation. In striking contrast with the dipolar approximation that strictly forbids RET towards or from dark states, our results demonstrate that dark states can take an active role in RET with interaction energies that, depending on the relative orientation of the chromophores, can be even larger than those relevant to allowed states. Essential-state models, whose predictions are quantitatively confirmed by TDDFT results, allow us to relate RET interaction energies towards allowed and dark states to the supramolecular symmetry of the RET-pair, offering reliable design strategies to optimize RET-interactions.

13.
Chemphyschem ; 12(5): 937-43, 2011 Apr 04.
Article in English | MEDLINE | ID: mdl-21384487

ABSTRACT

The changes in the electronic and magnetic properties of graphene induced by interaction with semiconducting oxide nanoparticles such as ZnO and TiO(2) and with magnetic nanoparticles such as Fe(3)O(4), CoFe(2)O(4), and Ni are investigated by using Raman spectroscopy, magnetic measurements, and first-principles calculations. Significant electronic and magnetic interactions between the nanoparticles and graphene are found. The findings suggest that changes in magnetization as well as the Raman shifts are directly linked to charge transfer between the deposited nanoparticles and graphene. The study thus demonstrates significant effects in tailoring the electronic structure of graphene for applications in futuristic electronic devices.

14.
Phys Rev Lett ; 101(17): 176805, 2008 Oct 24.
Article in English | MEDLINE | ID: mdl-18999773

ABSTRACT

We combine molecular dynamics simulations and density functional theory to analyze the electrical structure and transmission probability in four different DNA sequences under physiological conditions. The conductance in these sequences is primarily controlled by interstrand and intrastrand coupling between low-energy guanine orbitals. Insertion of adenine-thymine base pairs between the guanine-cytosine rich domains acts as a tunneling barrier. Our theory explains recent length dependent conductance data for individual DNA molecules in water.


Subject(s)
DNA/chemistry , Water/chemistry , Base Sequence , Computer Simulation , DNA/metabolism , Electric Conductivity , Electron Transport , Models, Chemical , Models, Molecular , Nucleic Acid Conformation , Solutions , Structure-Activity Relationship , Thermodynamics
15.
Phys Rev Lett ; 88(16): 166601, 2002 Apr 22.
Article in English | MEDLINE | ID: mdl-11955244

ABSTRACT

We present a theory of nonequilibrium long range charge transfer between donor and acceptor centers in a model polymer mediated by magnetic exciton (Kondo) bound states. Our model produces electron tunneling lengths easily exceeding 10 A, as observed recently in DNA and organic charge transfer systems. This long ranged tunneling is effective for weak to intermediate donor-bridge coupling, and is enhanced both by weak to intermediate strength Coulomb hole-electron attraction (through the orthogonality catastrophe) and by coupling to local vibrational modes.

16.
J Am Chem Soc ; 123(30): 7287-91, 2001 Aug 01.
Article in English | MEDLINE | ID: mdl-11472155

ABSTRACT

We investigate here the relationship between molecular architecture and two-photon absorption (TPA) processes in a class of alkyl-substituted 4-quinopyran chromophores. We find that TPA cross sections diverge as the one-photon gap energy nears one-half of the two-photon gap. The molecular strategy proposed here to tune these two-excitation gaps for maximizing TPA cross sections is to twist the molecule about the bond connecting the chromophore donor and acceptor phenylene fragments. Extremely large TPA cross sections, determined by the absorption bandwidth, can then be realized (imaginary part of the third-order polarizability approximately 2.6 x 10(5) x 10(-36) esu) for fundamental photon energies near 1.0 eV, when the torsional angle approaches 104 degrees. The required torsional angle is achieved by introduction of sterically encumbered 2,2',2' ',2' " tertiary alkyl substituents.

17.
Indian J Ophthalmol ; 39(3): 134-5, 1991.
Article in English | MEDLINE | ID: mdl-1841890

ABSTRACT

In recent times zinc is emerging as a nutrient of clinical importance and had been found to be low in serum in various disease conditions. In the current study 11 control cases and 22 corneal ulcer cases were taken. Their serum zinc level was measured by atomic absorption spectrophotometer. Serum zinc level in recalcitrant corneal ulcer cases was found to be below normal.


Subject(s)
Corneal Ulcer/blood , Zinc/blood , Humans , Spectrophotometry, Atomic
SELECTION OF CITATIONS
SEARCH DETAIL
...