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The three body fragmentation of methane dication has been studied using the technique of cold target recoil ion momentum spectroscopy. The process is initiated by impact of energetic Ar9+ ions on neutral methane and the data is subsequently collected in coincidence with Ar8+ projectile. By analysing the dissociation channels leading to (H + H+ + CH 2 + ) and (H + H 2 + + CH+) fragments, it is concluded that these fragments are formed in a sequential manner via formation of molecular intermediates CH 3 + and CH 2 + respectively. It is shown that these molecular intermediates carry a few eVs as their internal energies, part of which is released when they emit an H-atom with the open possibility that the final detected fragments may still be internally excited. This was accomplished by analysing the two-steps of the sequential process in their own native frames. For a molecular system having three-dimensional structure, our results prove to be an ideal example to highlight the importance of using native frames for correct interpretation of the obtained results. Our results indicate that the dissociation of methane dication can be a major source of production of H-atoms in addition to H+ fragments with the probability of the two being of similar order. [ABSTRACT FROM AUTHOR]

The three-body breakup of [ C 2 H 2 ] 3 + formed in collision with Xe9+ moving at 0.5 atomic units of velocity is studied by using recoil ion momentum spectroscopy. Three-body breakup channels leading to (H+, C+, CH+) and (H+, H+, C 2 + ) fragments are observed in the experiment and their kinetic energy release is measured. The breakup into (H+, C+, CH+) occurs via concerted and sequential modes, whereas the breakup into (H+, H+, C 2 + ) shows only the concerted mode. By collecting events coming exclusively from the sequential breakup leading to (H+, C+, CH+), we have determined the kinetic energy release for the unimolecular fragmentation of the molecular intermediate, [ C 2 H ] 2 + . By using ab initio calculations, the potential energy surface for the lowest electronic state of [ C 2 H ] 2 + is generated, which shows the existence of a metastable state with two possible dissociation pathways. A discussion on the agreement between our experimental results and these ab initio calculations is presented. [ABSTRACT FROM AUTHOR]

Guar gum is a specialty galactomannan that serves as an abundant, renewable and sustainable feedstock. Nevertheless, its films cannot be used for sustained drug delivery due to certain drawbacks such as susceptibility towards microbial contamination, high swelling rate, non-porous structure, and brittleness. Therefore, functionalization of galactomannan has been achieved by crosslinking with malonic acid, a green, water-soluble, simple organic dicarboxylic acid with minimum chain length possessing natural plasticizer properties using a green chemistry approach. Interestingly, malonic acid also acts as an auto catalyst during acylation and subsequent crosslinking. The reaction conditions were optimized by varying the concentrations of malonic acid (0.5%, 1.5%, and 2% w/v), temperature (55 °C, 100 °C, 120 °C, and 140 °C) and time (5, 10, and 15 min) to introduce 1,3-propane dioates in the galactomannan chains resulting in flexible crosslinked films of galactomannans. Furthermore, the effect of low and high curing temperatures on crosslinking has been investigated by the analysis of the degree of crosslinking for the first time. The mechanism of crosslinking with a dicarboxylic acid has also been proposed. Detailed analysis of films has been achieved by NMR (1D & 2D), FTIR, XRD, TGA and DSC. Furthermore, curcumin has been loaded in these crosslinked films and kinetic studies via the Korsmeyer--Peppas model demonstrate that curcumin has a non-Fickian diffusion controlled release (DCR) mechanism. The antibacterial, antifungal and antioxidant studies show that the prepared formulation has potential utility in sustained drug delivery and other biomedical applications. Altogether, these studies provide a foundation to develop a sustained drug release system using crosslinked films for wound healing, anticancer therapy and many more. [ABSTRACT FROM AUTHOR]

Purpose: Chemical eye injury is an acute emergency that can result in vision loss. Neurotrophic keratitis (NK) is the most common long-term manifestation of chemical injury. NK due to alkali burn affects ocular surface health and is one of its most common causes. Here, we established a rabbit model of corneal alkali burns to evaluate the severity of NK-associated changes. Material methods: Alkali burns were induced in NZ rabbits by treating the cornea with (i) a 5 mm circular filter paper soaked in 0.75 N NaOH for 10 s (Mild NK) and (ii) trephination using a guarded trephine (5 mm diameter and 150-micron depth), followed by alkali burn, with a 5 mm circular filter paper soaked in 0.75 N NaOH for 10 s (a severe form of NK). Immediately after, the cornea was rinsed with 10 mL of normal saline to remove traces of NaOH. Clinical features were evaluated on Day 0, Day 1, Day 7, Day 15, and Day 21 post-alkali burn using a slit lamp, Pentacam, and anterior segment optical coherence tomography (AS-OCT). NK-like changes in epithelium, sub-basal nerve plexus, and stroma were observed using in vivo confocal microscopy (IVCM), and corneal sensation were measured using an aesthesiometer post alkali injury. After 21 days, pro-inflammatory cytokines were evaluated for inflammation through ELISA. Results: Trephination followed by alkali burn resulted in the loss of epithelial layers (manifested using fluorescein stain), extensive edema, and increased corneal thickness (550 µm compared to 380 µm thickness of control) evaluated through AS-OCT and increased opacity score in alkali-treated rabbit (80 compared to 16 controls). IVCM images showed complete loss of nerve fibers, which failed to regenerate over 30 days, and loss of corneal sensation—conditions associated with NK. Cytokines evaluation of IL6, VEGF, and MMP9 indicated an increased angiogenic and pro-inflammatory milieu compared to the milder form of NK and the control. Discussion: Using clinical parameters, we demonstrated that the alkali-treated rabbit model depicts features of NK. Using IVCM in the NaOH burn animal model, we demonstrated a complete loss of nerve fibers with poor self-healing capability associated with sub-basal nerve degeneration and compromised corneal sensation. This pre-clinical rabbit model has implications for future pre-clinical research in neurotrophic keratitis. [ABSTRACT FROM AUTHOR]

We report on the direct experimental evidence of hydrogen migration in triply charged acetylene. The roaming hydrogen atom in a triply charged molecular ion is counter intuitive. The three body breakup channel C 2 H 2 3 + → H + + C + + C H + is studied using the technique of recoil ion momentum spectroscopy. The triply charged ion was generated in collisions of the neutral parent with a slow highly charged Xe9+ ion. Three different dissociation pathways have been identified and separated, namely, concerted breakup in an acetylene configuration, concerted breakup in a vinylidene configuration, and sequential breakup via a [ C 2 H ] 2 + intermediate, and the branching ratio for all three pathways are determined. [ABSTRACT FROM AUTHOR]

The ion-induced fragmentation of C H 4 2 + into H+ and C H 3 + is studied using a cold target recoil ion momentum spectroscopy in coincidence with the charge state of the post-collision projectile. Using constant velocity Ar9+ and N3+, results from four different datasets are presented, with a selection on the final charge state of the projectile (Ar8+ or Ar7+ and N2+ or N+). Three distinct dissociation pathways (I, II, and III) are observed for each dataset, with the mean kinetic energy release values of around 4.7, 5.8, and 7.9 eV, respectively. The electronic states that are populated correspond to electronic configurations (1 t 2 ) − 2 and (2 a 1 ) − 1 (1 t 2 ) − 1 of the methane dication, C H 4 2 + . The relative branching ratios between the three pathways are discussed as a function of the charge state of the post-collision projectile, and a strong correlation with the specific nature of the ion–molecule interaction is found. The existing ab initio calculations have provided an explanation only for pathway II. In this article, we propose an explanation for pathway III, but pathway I still remains unexplained and requires further theoretical efforts. A discussion of the dependence of dissociation on the mode of excitation is presented. [ABSTRACT FROM AUTHOR]

Electron acceleration due to the beating of two linearly polarized lasers of finite spot size at an arbitrary angle in a vacuum has been investigated. The interference at certain angles due to these lasers with slightly different frequencies interacting at any arbitrary angle has been studied. Due to the constructive interference between these lasers, their resultant electric and magnetic field points out in a particular direction, where the electron is injected for effective trapping and noticeable acceleration has been observed. Sensitiveness of chirp parameters on electron acceleration have been observed. Along with this, a periodic frequency chirp plays a crucial role in the improved acceleration of electron. In this way, electron energy is enhanced more conveniently. [ABSTRACT FROM AUTHOR]

Epigenetic mechanisms modulate gene expression and function without altering the base sequence of DNA. These reversible, heritable, and environment-influenced mechanisms generate various cell types during development and orchestrate the cellular responses to external stimuli by regulating the expression of genome. Also, the epigenetic modifications influence common pathological and physiological responses including inflammation, ischemia, neoplasia, aging and neurodegeneration etc. In recent past, the field of epigenetics has gained momentum and become an increasingly important area of biomedical research As far as eye is concerned, epigenetic mechanisms may play an important role in many complex diseases such as corneal dystrophy, cataract, glaucoma, diabetic retinopathy, ocular neoplasia, uveitis, and age-related macular degeneration. Focusing on the epigenetic mechanisms in ocular diseases may provide new understanding and insights into the pathogenesis of complex eye diseases and thus can aid in the development of novel treatments for these diseases. In the present review, we summarize the clinical perspective of infectious keratitis, role of epigenetics in infectious keratitis, therapeutic potential of epigenetic modifiers and the future perspective. [ABSTRACT FROM AUTHOR]

The technique of recoil ion momentum spectroscopy is employed to determine the complete momentum vectors for three fragment dissociation channels, [D2O](q+2) → (D+ + D+ + Oq+) with q = 1, 2, or 3 formed in collisions of isolated water molecules with 450 keV Xe9+ ions. The kinetic energy released in each of these dissociation channels is measured and angular correlations between the fragment momenta are determined. From the angular correlations of the three fragment ions with the direction of the incoming beam, a strong anisotropy in the emission of recoil fragments is reported. It is inferred that the molecular plane prefers to lie orthogonal to the incoming beam direction with certain orientations being more preferred than others and a clear signature of non-coplanar dissociation is also observed. [ABSTRACT FROM AUTHOR]

We report experimental evidence for molecular deformation due to a vibrationally active transition state of multiply charged acetylene molecules under the impact of low energy Ar8+ projectiles. “Butterflylike” structures are observed in the experimental coincidence spectra between hydrogen and carbon ionic fragments. Such structures can be generated by numerical simulations and are found to originate from the bending motion of the dissociating molecule. Angular distributions for dissociation products from triply charged C2H2 ion are reported. [ABSTRACT FROM AUTHOR]

• Electron acceleration by chirped echelon phase modulated (EPM) linearly polarised laser pulse in vacuum. • Enhancement in electron energy of about 2.5 GeV on account of suitable values of laser and magnetic field parameters. • Optimization of electron injection angle and magnetic field for enhanced electron acceleration. • Sensitiveness of chirp parameter and EPM gradient parameter on electron acceleration. Electron acceleration employing chirped echelon phase modulated (EPM) linearly polarised (LP) laser pulse in vacuum under the influence of axial magnetic field has been explored. Echelon supported laser pulse with phase modulation sustains the trapping of pre-accelerated electron in the most favourable phase. Furthermore, the addition of linear frequency chirp enlarges the electron laser interaction duration. Here, application of axial magnetic field serves a critical role in boosting the electron acceleration upto larger distances in the laser propagation direction. So, few MeV electron can be expedited up to GeV energy and retains it upto longer distances due to the collective influence of the frequency chirp and phase modulation. Effect of laser initial intensity, pulse duration, beam waist and electron injection is taken into consideration and optimized for enhanced energy gain. It is observed that the electron of initial energy ˜0.5 MeV can achieve energy of ˜2.5 GeV with I ∼ 1.38 × 10 20 W/cm2 due to chirped LP EPM laser pulse in the existence of suitable axial magnetic field (˜41.7 MG) at most favourable values of electron injection angle and EPM gradient parameter. [ABSTRACT FROM AUTHOR]

Introduction: Abnormal Uterine Bleeding is one of the commonest presentations of patients in gynecology OPD (Outdoor patient department). Abnormal uterine bleeding is a common sign of a number of different uterine disorders ranging from dysfunctional (non-organic) abnormalities or complications of pregnancy to organic lesions such as polyps, hyperplasia, or carcinoma. Materials and methods: Present study included 200 patients who attended OPD of Gynecology Department, with complaints of abnormal uterine bleeding. All the biopsy specimens were sent to Pathology Department. We had made an appropriate histopathological diagnosis for each case. The data was collected and analyzed statistically. Results: Out of 200 cases studied, 21% were found out to be secretory endometrium, 30% proliferative endometrium, 9% simple hyperplasia without atypia, 5% complex hyperplasia without atypia, 8% endometrial hyperplasia with atypia, 3% endometrial polyp, 8% chronic nonspecific endometritis, 2% tuberculous endometritis, 1% Arias-stella reaction, 10% products of conception, 1% complete and partial hydatidiform mole, 1% endometrial carcinoma and 1% squamous cell carcinoma of cervix. Conclusion: Endometrial biopsy is a safe, reliable and less time consuming outpatient procedure which can be used as an initial diagnostic tool in the patients with abnormal uterine bleeding.Introduction: Abnormal Uterine Bleeding is one of the commonest presentations of patients in gynecology OPD (Outdoor patient department). Abnormal uterine bleeding is a common sign of a number of different uterine disorders ranging from dysfunctional (non-organic) abnormalities or complications of pregnancy to organic lesions such as polyps, hyperplasia, or carcinoma. Materials and methods: Present study included 200 patients who attended OPD of Gynecology Department, with complaints of abnormal uterine bleeding. All the biopsy specimens were sent to Pathology Department. We had made an appropriate histopathological diagnosis for each case. The data was collected and analyzed statistically. Results: Out of 200 cases studied, 21% were found out to be secretory endometrium, 30% proliferative endometrium, 9% simple hyperplasia without atypia, 5% complex hyperplasia without atypia, 8% endometrial hyperplasia with atypia, 3% endometrial polyp, 8% chronic nonspecific endometritis, 2% tuberculous endometritis, 1% Arias-stella reaction, 10% products of conception, 1% complete and partial hydatidiform mole, 1% endometrial carcinoma and 1% squamous cell carcinoma of cervix. Conclusion: Endometrial biopsy is a safe, reliable and less time consuming outpatient procedure which can be used as an initial diagnostic tool in the patients with abnormal uterine bleeding. [ABSTRACT FROM AUTHOR]

Introduction: Cervical cancer is the major health burden in India. For detection in early stage, the screening test is Pap smear. To check the sensitivity and specificity of Bethesda system, the cytological findings have to be correlated with histology considering histopathology as gold standard. Materials and methods: This was a retrospective study conducted in Pathology Department of at tertiary care center; Saraswati Institute of Medical Science (SIMS), Hapur. Cytopathological findings were correlated with corresponding follow-up histopathological findings using revised 2014 Bethesda System. Results: Most of patients were of age group 41-50 years which was 56 (37.33%), followed by the age group 51-60 years which was 40 (26.67%). Majority cases were of parity 3 which were 51 cases (34%) followed by parity 4 which were 40 (26.67) with mean parity of patient being 3.30. Conclusion: The Pap smear has good sensitivity and specificity in detecting pre-neoplastic lesions of uterine cervix and it is cost effective too. [ABSTRACT FROM AUTHOR]

We investigate dissociation in flight of metastable molecular dications formed by ultrashort, intense laser pulses using the cold target recoil ion momentum spectroscopy technique. A method for retrieving the lifetime(s) of the transient metastable state(s) as well as the complete three-dimensional momenta of the dissociating fragments is presented. Specifically, we demonstrate and discuss this approach by focusing on dissociation in flight of the ethylene dication going to the deprotonation channel. Two lifetimes are found to be associated with this process, C2H42+→ C2H3+ + H+: τ1 = 202 ± 10 ns and τ2 = 916 ± 40 ns. For the corresponding channel in deuterated ethylene, lifetimes of τ1 = 269 ± 29 ns and τ2 = 956 ± 83 ns are obtained. [ABSTRACT FROM AUTHOR]

Events from the sequential and concerted modes of the fragmentation of OCS3+ that result in coincident detection of fragments C+, O+, and S+ have been separated using a newly proposed representation. An ion beam of 1.8 MeV Xe9+ is used to make the triply charged molecular ion, with the fragments being detected by a recoil ion momentum spectrometer. By separating events belonging exclusively to the sequential mode of breakup, the electronic states of the intermediate molecular ion (CO2+ or CS2+) involved are determined, and from the kinetic energy release spectra, it is shown that the low lying excited states of the parent OCS3+ are responsible for this mechanism. An estimate of branching ratios of events coming from sequential versus concerted mode is presented. [ABSTRACT FROM AUTHOR]

In an inverse free-electron laser (IFEL) scheme, a comparative study of single electron acceleration is carried out using a tightly focused Gaussian laser beam along with helical and planar wiggler fields. The effect of laser and wiggler field parameters is analyzed on single-electron dynamics and its acceleration. For the laser field descriptions, up to fifth-order corrections are included in the diffraction angle to study the effect of a tight laser pulse on electron acceleration. The Lorentz equation is solved using the fourth-order Runge Kutta method. Our numerical results indicate that considerable electron energy is attained for the helical and planar wiggler both for the optimal laser and wiggler field parameters, respectively. The effect of the laser field, its waist -size, and the effect of the wiggler field and its tapering along undulator length is studied for both helical and planar wiggler. The total electron energy gain for the helical wiggler case is 1.3 GeV due to the long interaction length while for the planar wiggler case, the electron energy gain is limited to 300 MeV only due to its shorter interaction length. This comparative analysis will certainly help us to understand the electron dynamics in IFEL and show the importance of helical wiggler over planar wiggler. [ABSTRACT FROM AUTHOR]

Members of the green fluorescent protein (GFP) family may undergo irreversible phototransformation upon irradiation with UV light. This provides clear evidence for the importance of the higher-energy photophysics of the chromophore, which remains essentially unexplored. By using time-resolved action and photoelectron spectroscopy together with high-level electronic structure theory, we directly probe and identify higher electronically excited singlet states of the isolated para- and meta-chromophore anions of GFP. These molecular resonances are found to serve as a doorway for very efficient electron detachment in the gas phase. Inside the protein, this band is found to be resonant with the quasicontinuum of a solvated electron, thus enhancing electron transfer from the GFP to the solvent. This suggests a photophysical pathway for photoconversion of the protein, where GFP resonant photooxidation in solution triggers radical redox reactions inside these proteins. [ABSTRACT FROM AUTHOR]

A new stability-indicating reversed-phase high-performance thin-layer chromatographic (RP-HPTLC) method for densitometric analysis of thiocolchicoside was developed and validated. The chromatograms were developed using aluminum plates pre-coated with silica gel 60 RP-18 F254S as a stationary phase and methanol : water (70 : 30 v/v) as a mobile phase. The compact band for thiocolchicoside was observed at Rf value of 0.60 ± 0.02 at an absorption wavelength of 377 nm. The linear regression data for the calibration plots (R² = 0.9984) was found with respect to peak area in the concentration range of 100-600 ng per band. The limit of detection (LOD) and limit of quantification (LOQ) were 9.77 ng and 29.63 ng, respectively. The drug was exposed to acidic and alkaline hydrolysis, oxidation, photo degradation, and dry heat conditions. The peaks of degradation products were well-resolved from the peak of the standard drug with significantly different Rf values. Statistical analysis proved that the established RP-HPTLC method is reproducible, selective, and accurate for the determination of thiocolchicoside in its formulations. The method can effectively separate the drug from its degradation products, and it can be considered as stability-indicating assay. [ABSTRACT FROM AUTHOR]

Abstract: We examine the effect of wiggler magnetic field on pulse slippage of short pulse laser-induced third harmonic generation in plasma. The process of third harmonic generation of an intense short pulse laser in plasma is resonantly enhanced by the application of a magnetic wiggler. The laser exerts a ponderomotive force at second harmonic driving density oscillations. The second harmonic oscillations coupled with electron velocity at the laser frequency, produces a non-linear current, driving the third harmonic. Third harmonic pulse generates in the fundamental pulse domain. However, the group velocity of the third harmonic wave is greater than the fundamental wave. Hence, the third harmonic pulse saturates strongly and moves forward from the fundamental pulse at shorter distance than the second harmonic pulse. [Copyright &y& Elsevier]

Unique characteristics of terahertz (THz) radiation can provide novel information in different fields of science and technology. In order to meet the demanding applications, the efficient THz radiations are highly needed. Therefore, in the present paper, we propose new schemes based on the interaction of nonrelativistic lasers with plasma. When an intense laser beam interacts with plasma, the electrons of plasma start oscillating and drives a nonlinear ponderomotive force results a nonlinear oscillatory velocity. By the beating of density ripple with this nonlinear velocity, a nonlinear current density appears. An efficient THz radiation is generated during laser-plasma interaction due to this nonlinear current density. The equations for terahertz field are derived with the help of Maxwell's 3rd and 4th equations to obtain the normalized amplitude of terahertz radiation. Scheme offered here is the adapted one to achieve efficient THz radiation by optimizing the laser-plasma parameters. [ABSTRACT FROM AUTHOR]