The theoretical basis for simultaneous oscillation of 2N - 3 laser lines is due to interference of N (for all even N > or = 2) pump beams in a distributed-feedback dye laser is described. Multiple gratings are produced in a dye solution by interference patterns of N/2 pairs of a frequency-doubled Nd:YAG laser. N/2 pairs of mutually time-delayed pulses induce multiple gratings of different periodicities, of which 2N - 3 gratings support oscillation of 2N - 3 lines and the remaining gratings, because of their larger periods, cannot support Bragg scattering. The maximum number of laser lines depends on the mutual delay between adjacent pairs of beams, coherence, states of polarization, pulse lengths, and of course the number of pulses. For three pairs of excitation beams derived from the same source through wave-front or amplitude phase division techniques, the output lasing lines varied from a minimum of three to a maximum of nine. This research was carried out by pumping of a dye solution with two, four, and six pulses, but the principle may be extended to multiple output lines, depending on the number of pump pulses and on the gain of the dye solution.
The goal of this study is to assess the risk of overexposure, when DFB dye laser is used for medical treatment in pulsed mode operation. Results of experimental study showing an unexpected rise of energy in pulses of distributed feedback dye laser (DFDL) output due to temperature phase gratings in dye cell during passively Q switched and mode-locked operation is reported. This unintended increase in the number of pulses, pulse duration, per pulse energy may cause side effects, when used for selective photothermolysis. To probe this phenomenon the most commonly used Rh6G dye was excited with 10-20 pulses of second harmonic of a passively Q switched and mode-locked Nd:yttrium-aluminum-garnet(YAG) laser. The outputs of DFDL and Nd:YAG laser were recorded by an Imacon-675 streak camera. The peak of DFDL output pulses was found delayed proportionally from the peak of the Nd:YAG pulses by more than an interpulse period of excitation laser. A computer program was used to simulate the experimentally measured results to estimate the thermal decay constants and energy retained by medium. The delay between peaks of Nd:YAG (input) and DFDL (output) pulses was found to vary from 10 to 14 ns for various cavity lengths. It was interesting to note that for smaller inter-pulse periods the effect of gradual gain buildup satisfied the threshold conditions for some of the pulses that otherwise cannot lase. This may lead to unintended increase in energy fluence causing overexposure-induced bio effects.
Seaweed cultivation has garnered significant interest, driven by its wide range of biomass benefits. However, comprehensive assessments from various perspectives are imperative to ensure the sustainable cultivation of seaweed. Biotic and Abiotic factors can significantly impact seaweed yield in complex commercial farming. Biotic factors include bacteria, fungi, viruses, and other algae, while abiotic factors include environmental conditions such as temperature, salinity, light intensity, and nutrient availability. Additionally, the susceptibility of seaweeds to pests and diseases further compounds the issue, leading to potential crop losses. This study endeavours to shed light on the immense potential of macroalgae cultivation and underscores the pressing need for scientific advancements in this field. The comprehensive review clearly explains the latest developments in seaweed cultivation and highlights significant advances from diverse seaweed research. Moreover, it provides insightful glimpses into possible future developments that could shape the trajectory of this promising industry.
Gelucire 50/13 alone and solid dispersions in this material containing two model drugs (10% w/w caffeine and paracetamol) have been studied with a view to establishing the mechanism underpinning changes in drug-release characteristics as a function of storage time and temperature. The lipid systems were fabricated into tablets and stored for up to 180 days at temperatures of 20 and 37 degrees C. The dispersions were studied using differential scanning calorimetry (DSC), scanning electron microscopy, and dissolution testing. DSC studies indicated that the Gelucire 50/13 exists in two principal melting forms (melting points 38 and 43 degrees C) that undergo transformation to the higher melting form on storage at 37 degrees C. Scanning electron microscopy studies indicated that the systems exhibit "blooming," with crystal formation on the surface being apparent on storage at both temperatures. The dissolution rate increased on storage, with the effect being particularly marked at higher storage temperatures and for the paracetamol systems. However, whereas these changes corresponded well to those seen for the morphology, the correlation between the changes in dissolution and those of the DSC profiles was poor. The study has suggested a novel explanation for the storage instability of Gelucire 50/13 whereby the change in dissolution is associated not with molecular rearrangement as such but with the gross distribution of the constituent components, this in turn altering the physical integrity of the lipid bases.
Cancer is a prominent cause of morbidity and mortality worldwide, in spite of advances in therapeutic interventions and supportive care. In 2018 alone, there were 18·1 million new cancer cases and 9·6 million deaths indicating the need for novel anticancer agents. Plant-based products have often been linked with protective effects against communicable and non-communicable diseases. Recently, we have shown that animals such as crocodiles thrive in polluted environments and are often exposed to carcinogenic agents, but still benefit from prolonged lifespan. The protective mechanisms shielding them from cancer could be attributed to the immune system, and/or it is possible that their gut microbiota produce anticancer molecules. In support, several lines of evidence suggest that gut microbiota plays a critical role in the physiology of its host. Here, we reviewed the available literature to assess whether the gut microbiota of animals thriving in polluted environment possess anticancer molecules.
BACKGROUND: The prevalence of type 2 diabetes mellitus (T2DM) is increasing at an alarming rate in developing countries. The accompanying complications of T2DM can be reduced by maintaining a good adherence to medication and self-care activities.
OBJECTIVES: To evaluate medication adherence and self-care behaviors among patients with T2DM.
METHODS: A total of 497 subjects with T2DM were recruited from three hospitals and a government clinic in the state of Selangor, Malaysia. Previously validated scales were used to measure medication adherence (Morisky Medication Adherence Scale) and diabetes self-care activities (Summary of Diabetes Self-Care Activities). Pearson correlation coefficient was used to investigate the relationship between the risk factors and medication adherence. Pearson χ2 test of association was used to test significant association.
RESULTS: The mean age of the subjects was 55.5 years. The mean Morisky Medication Adherence Scale score was 5.65 ± 1.97, indicating a moderate adherence level to medication. Among the subjects who had low adherence level, 50.9% were Malays, followed by 34.2% Indians. The Pearson χ2 test of association indicated a significant association (P = 0.000) between ethnicity and medication adherence. The subjects had better self-care behaviors in their general diet (mean 5.04 ± 1.88) and poor self-care behaviors in blood sugar testing (mean 2.13 ± 2.34).
CONCLUSIONS: The Malaysians had a moderate medication adherence level, whereas they were nonadherent to blood glucose testing. Emphasis on self-care activities and medication adherence is relevant to improve outcomes in the management of T2DM.
The genus Garcinia is reported to possess antimicrobial, anti-inflammatory, anticancer, hepatoprotective and anti-HIV activities. Garcinia hombroniana in Malaysia is used to treat itching and as a protective medicine after child birth. This study was aimed to isolate the chemical constituents from the bark of G. hombroniana and explore their possible pharmacological potential. Ethyl acetate extract afforded one new (1) and six (2-7) known 3 → 8 rotameric biflavonoids. Their structures were elucidated by UV, IR and NMR (1D and 2D) spectroscopy together with electron ionization/ESI mass spectrometric techniques and were identified as (2R, 3S) volkensiflavone-7-O-rhamnopyranoside (1), volkensiflavone (2), 4″-O-methyl-volkensiflavone (3), volkensiflavone-7-O-glucopyranoside (4), morelloflavone (5), 3″-O-methyl-morelloflavone (6) and morelloflavone-7-O-glucopyranoside (7). The absolute configuration of compound 1 was assigned by circular dichroism spectroscopy as 2R, 3S. The coexistence of conformers of isolated biflavonoids in solution at 25 °C in different solvents was confirmed by variable temperature NMR studies. At room temperature (25 °C), compounds 1-7 exhibited duplicate NMR signals, while at elevated temperature (90 °C), a single set of signals was obtained. Compound 5 showed significant in vitro antioxidant activities against 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis-3-ethyl benzthiazoline-6-sulfonic acid radicals. The antibacterial studies showed that compounds 5 and 6 are the most active against Staphylococcus aureus, Bacillus subtilis and Escherichia coli. Compounds 3 and 6 also showed moderate antituberculosis activity against H38 Rv. Based on the research findings, G. hombroniana could be concluded as a rich source of flavanone-flavone (3 → 8) biflavonoids that exhibit rotameric behaviour at room temperature and display significant antioxidant and antibacterial activities.
Here, we hypothesized that the microbial gut flora of animals/pests living in polluted environments, produce substances to thwart bacterial infections. The overall aim of this study was to source microbes inhabiting unusual environmental niches for potential antimicrobial activity. Two cockroach species, Gromphadorhina portentosa (Madagascar) and Blaptica dubia (Dubia) were selected. The gut bacteria from these species were isolated and grown in RPMI 1640 and conditioned media were prepared. Conditioned media were tested against a panel of Gram-positive (Methicillin-resistant Staphylococcus aureus, Streptococcus pyogenes, Bacillus cereus) and Gram-negative (Escherichia coli K1, Salmonella enterica, Serratia marcescens, Pseudomonas aeruginosa, Klebsiella pneumoniae) bacteria, as well as the protist pathogen, Acanthamoeba castellanii. The results revealed that the gut bacteria of cockroaches produce active molecule(s) with potent antibacterial properties, as well as exhibit antiamoebic effects. However, heat-inactivation at 95°C for 10 min had no effect on conditioned media-mediated antibacterial and antiamoebic properties. These results suggest that bacteria from novel sources i.e. from the cockroach's gut produce molecules with bactericidal as well as amoebicidal properties that can ultimately lead to the development of therapeutic drugs.
SIGNIFICANCE AND IMPACT OF THE STUDY: The bacteria isolated from unusual dwellings such as the cockroaches' gut are a useful source of antibacterial and antiamoebal molecules. These are remarkable findings that will open several avenues in our search for novel antimicrobials from unique sources. Furthermore studies will lead to the identification of molecules to develop future antibacterials from insects.
The aims of the present research were to mask the intensely bitter taste of sumatriptan succinate and to formulate orally disintegrating tablets (ODTs) of the taste masked drug. Taste masking was performed by coating sumatriptan succinate with Eudragit EPO using spray drying technique. The resultant microspheres were evaluated for thermal analysis, yield, particle size, entrapment efficiency and in vitro taste masking. The tablets were formulated by mixing the taste masked microspheres with different types and concentrations of superdisintegrants and compressed using direct compression method followed by sublimation technique. The prepared tablets were evaluated for weight variation, thickness, hardness, friability, drug content, water content, in vitro disintegration time and in vitro drug release. All the tablet formulations disintegrated in vitro within 37-410 s. The optimized formulation containing 5% Kollidon CL-SF released more than 90% of the drug within 15 min and the release was comparable to that of commercial product (Suminat®). In human volunteers, the optimized formulation was found to have a pleasant taste and mouth feel and disintegrated in the oral cavity within 41 s. The optimized formulation was found to be stable and bioequivalent with Suminat®.
A polyglycolised glyceride carrier, Gelucire 50/13, was incorporated with paracetamol as a model drug, filled into hard gelatin capsules and stored at three different temperatures for various lengths of time. The resultant solidified matrix within the capsule was subjected to thermal analysis using differential scanning calorimetry (DSC) to ascertain its supramolecular structure. Polymorphic transformations towards more stable gelucire forms were observed upon aging the matrices, with samples stored at a temperature near the melting range of the lower temperature gelucire melting fraction showing the most profound changes. The increase in the rate of drug release from aged samples could be correlated to the alterations to the supramolecular structure of the gelucire. Accelerated drug release from aged samples could also be seen from in vivo studies using healthy human volunteers, although the extent of absorption was not affected. Therefore, even though the sustainability of release may be compromised by aging the gelucire matrices, the bioavailability of the incorporated drug is unlikely to be affected.
The aim of this study was to formulate cost effective taste-masked orally disintegrating tablets of ondansetron, a bitter drug using different superdisintegrants by a wet granulation technique. Microcrystalline cellulose (Avicel) as a diluent and disintegrant in addition to aspartame as a sweetener were used in all formulations. The prepared tablets were evaluated for weight variation, thickness, hardness, friability, drug content, water content, in vitro disintegration time and in vitro drug release. The tablets' hardness was maintained in the range of 2-3 kg and friability was <1% for all batches. All tablet formulations disintegrated rapidly in vitro within 5.83 to 33.0 sec. The optimized formulation containing 15% Polyplasdone XL-10 released more than 90% of drug within 5 min and the release was comparable to that of a commercial product. In human volunteers, optimized formulation was found to have a pleasant taste and mouth feel and they disintegrated in the oral cavity within 12 sec. The stability results were also satisfactory. A pharmacokinetic study with the optimized formulation was performed in comparison with a reference (Zofer MD 8®) and they were found to be bioequivalent. In conclusion, a cost effective ondansetron orally disintegrating tablet was successfully prepared with acceptable hardness, desirable taste and rapid disintegration in the oral cavity.
The usefulness and validity of blood glucose measurement as an index of diabetic control were assessed with reference to serum fructosamine. Two hundred and twenty-eight non-insulin dependent diabetic out-patients were studied in the usual clinical setting. Fasting blood glucose (FBG) concentration was positively correlated with serum fructosamine (r = 0.42, t = 6.78 p less than 0.01). On the basis of their serum fructosamine concentrations, patients were divided into 3 groups. They were good control (fructosamine less than or equal to 288 umol/l), acceptable control (fructosamine less than or equal to 320 umol/l) and poor control groups (fructosamine greater than 320 umol/l). The mean fasting blood glucose concentration was significantly higher in the latter than the former 2 groups. However, at each level of control, there was a wide range of FBG concentrations. Thus, the value of FBG in predicting glycaemic control is limited. Its positive predictive value was only 32%, and its overall accuracy as an index of diabetic control was only 58% though its negative predictive value was high (93%). In 162 patients with poor diabetic control as indicated by their serum fructosamine concentrations, 81 (50%) of them had FBG less than 10 mmol/l on their clinic visit day. Fasting blood glucose is therefore not a reliable measure of good diabetic control, though it is useful in predicting poor control. FBG is simple to measure, cheap and rapidly available on clinic day, thus ensuring its continuing use. Doctors should be aware of its limitations and should not rely solely on FBG to assess diabetic control.
Study site: Diabetic clinic, Hospital Mentakab, Pahang, Malaysia
Solid lipid nanoparticles of atovaquone (ATQ-SLN) were prepared by high shear homogenization method using tripalmitin, trilaurin, and Compritol 888 ATO as the lipid matrices and Phospholipon 90H, Tween 80, and poloxamer 188 as the surfactants. Optimization of the formulations was conducted using 6 sets of 2(4) full-factorial design based on four independent variables that were the number of homogenizing cycles, concentration of the lipid, concentration of the co-surfactant, and concentration of the main surfactant. The dependent variables were particle size and polydispersity index (PdI). The homogenizing cycles showed a negative influence on the dependent variables which reduced both the particle size and the PdI value. Moreover, a combination of certain percentages of the main surfactant and co-surfactant also showed a negative influence that reduced both the particle size and PdI value. Selected formulations from each design were further characterized for the entrapment efficiency and yield. The optimised formulation of ATQ-SLN consisted of trilaurin, Phospholipon 90H and Tween 80 with a particle size of 89.4 ± 0.2 nm and entrapment efficiency of 83.0 ± 1.7%. The in-vitro release evaluation of the formulation showed a complete and immediate release of ATQ from the SLN that could be a solution to improve the poor aqueous solubility and hence poor bioavailability of the drug.
The dichloromethane bark extract of Garcinia hombroniana yielded one new cycloartane triterpene; (22Z,24E)-3β-hydroxycycloart-14,22,24-trien-26-oic acid (1) together with five known compounds: garcihombronane G (2), garcihombronane J (3), 3β acetoxy-9α-hydroxy-17,14-friedolanostan-14,24-dien-26-oic acid (4), (22Z, 24E)-3β, 9α-dihydroxy-17,14-friedolanostan-14,22,24-trien-26-oic acid (5) and 3β, 23α-dihydroxy-17,14-friedolanostan-8,14,24-trien-26-oic acid (6). Their structures were established by the spectral techniques of NMR and ESI-MS. These compounds together with some previously isolated compounds; garcihombronane B (7), garcihombronane D (8) 2,3',4,5'-tetrahydroxy-6-methoxybenzophenone (9), volkensiflavone (10), 4''-O-methyll-volkensiflavone (11), volkensiflavone-7-O-glucopyranoside (12), volkensiflavone-7-O-rhamnopyranoside (13), Morelloflavone (14), 3''-O-methyl-morelloflavone (15) and morelloflavone-7-O-glucopyranoside (16) were evaluated for cholinesterase enzymes inhibitory activities using acetylcholinesterase and butyrylcholinesterase. In these activities, compounds 1-9 showed good dual inhibition on both the enzymes while compounds 10-16 did not reasonably contribute to both the cholinesterases inhibitory effects.
Microbial electrosynthesis is a new approach to converting C1 carbon (CO2) to more complex carbon-based products. In the present study, CO2, a potential greenhouse gas, was used as a sole carbon source and reduced to value-added chemicals (acetate, ethanol) with the help of bioelectrochemical reduction in microbial electrosynthesis systems (MES). The performance of MES was studied with varying electrode materials (carbon felt, stainless steel, and cobalt electrodeposited carbon felt). The MES performance was assessed in terms of acetic acid and ethanol production with the help of gas chromatography (GC). The electrochemical characterization of the system was analyzed with chronoamperometry and cyclic voltammetry. The study revealed that the MES operated with hybrid cobalt electrodeposited carbon felt electrode yielded the highest acetic acid (4.4 g/L) concentration followed by carbon felt/stainless steel (3.7 g/L), plain carbon felt (2.2 g/L), and stainless steel (1.87 g/L). The alcohol concentration was also observed to be highest for the hybrid electrode (carbon felt/stainless steel/cobalt oxide is 0.352 g/L) as compared to the bare electrodes (carbon felt is 0.22 g/L) tested, which was found to be in correspondence with the pH changes in the system. Electrochemical analysis revealed improved electrotrophy in the hybrid electrode, as confirmed by the increased redox current for the hybrid electrode as compared to plain electrodes. Cyclic voltammetry analysis also confirmed the role of the biocatalyst developed on the electrode in CO2 sequestration.
This article summarises the development of mental health legislation in Singapore in three distinctive periods: pre-1965; 1965-2007 and 2007 onwards. It highlights the origin of mental health legislation and the relationship between mental health services and legislation in Singapore. The Mental Health (Care and Treatment) Act 2008 and Mental Capacity Act 2008 are described in detail.
Parasitic infections have remained a significant burden on human and animal health. In part, this is due to lack of clinically-approved, novel antimicrobials and a lack of interest by the pharmaceutical industry. An alternative approach is to modify existing clinically-approved drugs for efficient delivery formulations to ensure minimum inhibitory concentration is achieved at the target site. Nanotechnology offers the potential to enhance the therapeutic efficacy of drugs through modification of nanoparticles with ligands. Amphotericin B, nystatin, and fluconazole are clinically available drugs in the treatment of amoebal and fungal infections. These drugs were conjugated with gold nanoparticles. To characterize these gold-conjugated drug, atomic force microscopy, ultraviolet-visible spectrophotometry and Fourier transform infrared spectroscopy were performed. These drugs and their gold nanoconjugates were examined for antimicrobial activity against the protist pathogen, Acanthamoeba castellanii of the T4 genotype. Moreover, host cell cytotoxicity assays were accomplished. Cytotoxicity of these drugs and drug-conjugated gold nanoparticles was also determined by lactate dehydrogenase assay. Gold nanoparticles conjugation resulted in enhanced bioactivity of all three drugs with amphotericin B producing the most significant effects against Acanthamoeba castellanii (p ＜ 0.05). In contrast, bare gold nanoparticles did not exhibit antimicrobial potency. Furthermore, amoebae treated with drugs-conjugated gold nanoparticles showed reduced cytotoxicity against HeLa cells. In this report, we demonstrated the use of nanotechnology to modify existing clinically-approved drugs and enhance their efficacy against pathogenic amoebae. Given the lack of development of novel drugs, this is a viable approach in the treatment of neglected diseases.