147 research outputs found
Spectroscopic study of Herbig Ae/Be stars in the Galactic Anti-center region from LAMOST DR5
We study a sample of 119 Herbig Ae/Be stars in the Galactic anti-center
direction using the spectroscopic data from Large sky Area Multi-Object fiber
Spectroscopic Telescope (LAMOST) survey program. Emission lines of hydrogen
belonging to the Balmer and Paschen series, and metallic lines of species such
as FeII, OI, CaII triplet are identified. A moderate correlation is observed
between the emission strengths of H and FeII 5169 \r{A}, suggesting a
possible common emission region for FeII lines and one of the components of
H. We explored a technique for the extinction correction of the HAeBe
stars using diffuse interstellar bands present in the spectrum. We estimated
the stellar parameters such as age and mass of these HAeBe stars, which are
found to be in the range 0.1 -- 10 Myr and 1.5 -- 10 , respectively.
We found that the mass accretion rate of the HAeBe stars in the Galactic
anti-center direction follows the relation
, which is similar to the relation derived for
HAeBe stars in other regions of the Galaxy. The mass accretion rate of HAeBe
stars is found to have a functional form of with age, in agreement with previous studies.Comment: 18 pages, 11 figures, 3 tables, accepted for publication in MNRA
PORPHYSOMES-A PARADIGM SHIFT IN TARGETED DRUG DELIVERY
A novel drug delivery system is the one that ensures optimum dose at the right time, at the right location. Porphysomes are among those drug delivery systems. Porphysomes are a means of vesicular drug delivery systems. They are liposome-like structures composed completely of porphyrin lipid. The porphysomes encapsulates the active medicament in vesicular structure. They are having an aqueous core which can be loaded with the medicament. They have the capacity to destroy the disease tissues. They absorb the heat in the near infrared region and release this heat to destroy the diseased tissues. Porphysomes are having immense applications in the field of positron-electron therapy (PET), photoacoustic imaging, photothermal therapy etc. This review article discusses regarding the Porphysome-the drug delivery system, its advantages and disadvantages, composition, method of preparation, applications and various aspects related to the porphysomal drug delivery
CRYPTOSOMES: A REVOLUTIONARY BREAKTHROUGH IN NOVEL DRUG DELIVERY
The vesicular drug delivery systems are promising approaches to overthrown the problems of drugs having lesser bioavailability and rapid elimination from the body. The four type of lipid based drug delivery systems are: solid-lipid particulate system, emulsion based system, solid lipid tablet and vesicular system. Cryptosomes, a novel emerging vesicular drug delivery system which can overcome the disadvantages associated with conventional drug delivery systems like high stability, increased bioavailability, sustained release, decreased elimination of rapidly metabolizable drugs etc. The word Cryptosome was orginated from Greek word ‘’Crypto’’ means hidden and ‘’Soma’’ means body. It is formed from the mixture of phospholipids like distearoyl phosphatidyl ethanolamine-polyethylene glycol (DSPE-PEG) with distearoylphosphatidylcholine. These entire information regarding its origin and formation is explained in Dinesh Kumar et al. Vesicular systems symbolizes the use of vesicles in the different fields as carrier system or additives. This review disclose various vesicular drug delivery system and point out the advancement of cryptosome in the world of drug delivery.
This review would help researchers involved in the field of vesicular drug delivery
FORMULATION AND EVALUATION OF LORAZEPAM ENCAPSULATED COLLAGEN/PECTIN BUCCAL PATCH
Objective: To formulate and characterize Lorazepam loaded buccal patches using mucoadhesive, biodegradable, natural polymers-pectin (hydrophilic) and collagen (lipophilic) for treating epileptic seizures.
Methods: Lorazepam loaded buccal patches were prepared by solvent casting method and were subjected to various Physico-chemical evaluation parameters to find the optimized buccal patch. The in vitro drug release study and ex vivo permeation study was carried out. The stability study and histopathological study of optimized Lorazepam loaded buccal patch was also carried out.
Results: From in vitro drug release study, it was found that Lorazepam loaded buccal patch (B4) exhibited maximum drug release of 96.16 %±0.07 than other formulations at the end of 4 h, indicating an initial burst release followed by sustained release with release kinetics as Higuchi diffusion model. Based on the in vitro drug release, % drug content, % swelling index, folding endurance, B4 formulation was considered as optimised formulation and was further characterized. Ex vivo permeation study revealed that the cumulative amount of drug permeated from optimised Lorazepam loaded buccal patch (B4) was higher (3831.4±0.21µg/cm2) than marketed Midazolam buccal solution (1724±0.12 µg/cm2) and control drug solution (895.42±0.07 µg/cm2) with an enhancement ratio of 4.8. B4 formulation also showed a higher flux value (12.52±0.02µg/cm2/hr) compared to marketed formulation (5.732±0.01 µg/cm2) and control drug solution (2.563±0.03 µg/cm2) of P<0.05. The histopathological study using bovine buccal mucosa revealed that the B4 formulation is safe for buccal application. The stability study confirmed that B4 formulation is stable in both room and refrigeration conditions. Hence the formulated Lorazepam loaded buccal patch seems to be a promising carrier for the enhanced buccal delivery of Lorazepam in treating epileptic seizures.
Conclusion: The formulated Lorazepam loaded collagen/pectin buccal patch was found to be an efficient and stable route for the buccal delivery of Lorazepam in treating acute epileptic seizures which could be further explored scientifically
Self-sorting of nonmuscle myosins IIA and IIB polarizes the cytoskeleton and modulates cell motility
Nonmuscle myosin II (NMII) is uniquely responsible for cell contractility and thus defines multiple aspects of cell behavior. To generate contraction, NMII molecules polymerize into bipolar minifilaments. Different NMII paralogs are often coexpressed in cells and can copolymerize, suggesting that they may cooperate to facilitate cell motility. However, whether such cooperation exists and how it may work remain unknown. We show that copolymerization of NMIIA and NMIIB followed by their differential turnover leads to self-sorting of NMIIA and NMIIB along the front–rear axis, thus producing a polarized actin–NMII cytoskeleton. Stress fibers newly formed near the leading edge are enriched in NMIIA, but over time, they become progressively enriched with NMIIB because of faster NMIIA turnover. In combination with retrograde flow, this process results in posterior accumulation of more stable NMIIB-rich stress fibers, thus strengthening cell polarity. By copolymerizing with NMIIB, NMIIA accelerates the intrinsically slow NMIIB dynamics, thus increasing cell motility and traction and enabling chemotaxis
A review of antibiotic synergy in carbapenemase-producing bacteria
The problem of antibiotic resistance has garnered too much attention over the last few decades for posing a global hazard to the clinical handling and the inhibition of several deadly infections caused by bacteria. It burdens the world not only clinically but also economically... Antibiotic agents known as carbapenems are a very effective and typically designated for the treatment of multidrug-resistant (MDR) bacterial infections. To identify a suitable antibiotic combination to be used in vivo, one must be able to determine the synergism between the antibiotics in vitro. Several methods, such as the checkerboard method, multiple-combination bactericidal test, time-kill and E-test, have been used for this purpose. However, the lack of proper standardization procedures, types of bacterial agents, bacterial load, stage of infection and other factors make it very difficult to reproduce or correlate the results with other methods.Carbapenem-destroying lactases, which have recently emerged as mechanisms of resistance, are increasing in number and decreasing the treatment alternatives available. These infections are treated with colistin and tigecycline, but monotherapy may result in clinical breakdown because of a variety of factors. To control these infections, clinicians often choose combinations of drugs over monotherapy. There is an extreme lack of information on synergistic antibiotic combinations accounting for the diverse mechanisms of GNB resistance commonly encountered. The incidence of carbapenem-resistant GNB in Indian articles is also unknown. Therefore, we anticipate that this study may provide methodology for the selection of an appropriate antibiotic combination
Mental health status and perceived burden in caregiving spouses of persons with psychotic illness (a study from India)
Mental illness poses a great deal of burden on other family members, particularly the primary caregiver. In the Indian context for a married person with mental illness, the caregiving burden is usually experienced by the spouse, who is considered to be the ‘natural’ option. This quantitative study used survey methodology to assess caregiving burden in fifty spouses of persons diagnosed with a psychotic illness. Data was collected at a neuro-psychiatric facility in Tiruchirappalli, India. The Depression, Anxiety and Stress Scale and the Burden Assessment Schedule were the instruments administered to assess the mental health status of the spouse and their perceived burden. Findings revealed that the majority of spouses were classified as experiencing ‘severe’ and ‘extremely severe’ in terms of their depression, anxiety and stress levels and ‘high’ in terms of perceived burden. The specific ‘type’ of clinical diagnosis, however, did not differentiate the spouses on the key variables studied. The correlation of these key variables with other background variables has also been examined. The implications of the results of this study for psychosocial intervention have also been discussed in this article
Are Narrow-line Seyfert 1 Galaxies Powered by Low-mass Black Holes?
Narrow-line Seyfert 1 galaxies (NLS1s) are believed to be powered by the accretion of matter onto low-mass black
holes (BHs) in spiral host galaxies with BH masses MBH ∼ 106–108 Msun. However, the broadband spectral energy distribution of the γ-ray-emitting NLS1s are found to be similar to flat-spectrum radio quasars. This challenges our
current notion of NLS1s having low MBH. To resolve this tension of low MBH values in NLS1s, we fitted the
observed optical spectrum of a sample of radio-loud NLS1s (RL-NLS1s), radio-quiet NLS1s (RQ-NLS1s), and
radio-quiet broad-line Seyfert 1 galaxies (RQ-BLS1s) of ∼500 each with the standard Shakura–Sunyaev accretion
disk (AD) model. For RL-NLS1s we found a mean log(MBH,AD/Msun) of 7.98 ± 0.54. For RQ-NLS1s and RQ-BLS1s
we found mean log(MBH,AD/Msun) of 8.00 ± 0.43 and 7.90 ± 0.57, respectively. While the derived MBH,AD values of
RQ-BLS1s are similar to their virial masses, for NLS1s the derived MBH,AD values are about an order of magnitude
larger than their virial estimates. Our analysis thus indicates that NLS1s have MBH similar to RQ-BLS1s and their
available virial MBH values are underestimated, influenced by their observed relatively small emission line widths.
Considering the Eddington ratio as an estimation of the accretion rate and using MBH,AD, we found the mean accretion
rate of our RQ-NLS1s, RL-NLS1s, and RQ-BLS1s as 0.06, 0.05 and 0.05, respectively. Our results, therefore, suggest that NLS1s have BH masses and accretion rates that are similar to BLS1s.</p
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