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1.
Ophthalmology ; 129(6): 661-667, 2022 06.
Article in English | MEDLINE | ID: mdl-35143800

ABSTRACT

PURPOSE: To evaluate the outcomes of uveitic macular edema at 6 and 12 months in patients treated with methotrexate or mycophenolate mofetil. DESIGN: Subanalysis of a block-randomized, observer-masked, multicenter clinical trial. PARTICIPANTS: Patients were enrolled in the First-line Antimetabolites as Steroid-sparing Treatment (FAST) Uveitis Trial between August 2013 and August 2017. METHODS: Patients were randomized to oral methotrexate 25 mg weekly or mycophenolate mofetil 1.5 g twice daily for 12 months, along with a corticosteroid taper. In addition to standardized clinical examination, all patients underwent spectral-domain OCT imaging at each visit. At the 6-month primary end point, patients who achieved treatment success continued the same treatment for a subsequent 6 months, and treatment failures switched to the other treatment group. MAIN OUTCOME MEASURES: Prespecified 6-month primary outcome and 12-month outcomes of central subfield thickness and visual acuity. RESULTS: Of 216 patients in the FAST Trial, 42 eyes (30 patients) in the methotrexate group and 55 eyes (41 patients) in the mycophenolate group had uveitic macular edema. Baseline median central subfield thickness was 359 µm and 342 µm in the methotrexate and mycophenolate groups, respectively. At 12 months, for those who stayed on the same treatment, macular thickness decreased from baseline by 30.5 µm (interquartile range [IQR], -132.3 to 4.0) and 54 µm (IQR, -95.5 to -4.5) in the methotrexate and mycophenolate groups, respectively (P = 0.73). In patients who switched treatment at 6 months, macular thickness decreased from baseline by 12.5 µm (IQR, -32.3 to -0.5) and 50 µm (IQR, -181.0 to -10.0) in the methotrexate and mycophenolate groups, respectively (P = 0.34). At 12 months, 7 of 19 eyes (37%) on methotrexate had resolution of macular edema compared with 15 of 25 eyes (60%) on mycophenolate (P = 0.10). For those who switched treatments, 8 of 17 eyes (47%) on methotrexate and 6 of 11 eyes (55%) on mycophenolate had resolution of macular edema (P = 0.92). CONCLUSIONS: Treatment with methotrexate or mycophenolate mofetil for uveitic macular edema results in similar improvements in macular thickness at 6 and 12 months. At 12 months, approximately half of eyes in each antimetabolite group still had persistent macular edema.


Subject(s)
Macular Edema , Uveitis , Antimetabolites/therapeutic use , Enzyme Inhibitors/therapeutic use , Humans , Immunosuppressive Agents , Macular Edema/diagnosis , Macular Edema/drug therapy , Macular Edema/etiology , Methotrexate/therapeutic use , Mycophenolic Acid/therapeutic use , Steroids/therapeutic use , Tomography, Optical Coherence , Treatment Outcome , Uveitis/complications , Uveitis/diagnosis , Uveitis/drug therapy
2.
Bull Environ Contam Toxicol ; 109(6): 962-968, 2022 Dec.
Article in English | MEDLINE | ID: mdl-35366066

ABSTRACT

Inland lake is one of the important sources of freshwater ecosystem and serves as a sentinel to the changing aquatic biodiversity. Chlorophyll-a (Chl-a) is a major biological indicator and essential measure of the eutrophic status of lake water because it is strongly related to algae biomass. In the present research, bio-optical algorithms were developed based on the semi-empirical approach using the spectral wavelengths of 400 to 800 nm from hyperspectral remote sensing measurement and compared with Sentinel-2MSI image for estimation of Chl-a concentration in the lake water. The results show that the bio-optical algorithm can estimate and predict the algae pigment (Chl-a) concentration in the eutrophic lake with good accuracy of R2 of 0.8958, root mean squared error of 13.028, and mean absolute percentage error of 8.44%. The developed algorithm will be suitable and potential for monitoring algae spatial dynamics and assessment in an inland lake.


Subject(s)
Ecosystem , Lakes , Hyperspectral Imaging , Environmental Monitoring/methods , Eutrophication , Water
3.
Indian J Crit Care Med ; 25(2): 166-171, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33707894

ABSTRACT

BACKGROUND: Critically ill patients are under stress, leading to a catabolic response and higher energy expenditure. The associated malnutrition leads to adverse outcomes. AIMS AND OBJECTIVES: This study aims to assess the nutritional adequacy (>80% of prescribed calories) in mechanically ventilated (MV) patients and its effects on patients' outcomes. It also aims to identify the causes of deviation from the nutrition prescription. MATERIALS AND METHODS: This is a prospective observational study involving all adult critically ill patients requiring MV for >48 hours. Patients were prescribed enteral nutrition (EN) targeted to achieve 25 kcal/kg (IBW) of energy and 1.2 g/kg of proteins daily. Standard polymeric formula feeds were initiated as continuous infusion as per the feeding protocol in the intensive care unit (ICU). Data were collected on demography, body mass index (BMI), indication for ICU admission, admission category, and admission APACHE II and SOFA scores, and nutritional risk was captured with mNUTRIC score. Nutritional data on type of feed initiated, amount of calories prescribed/achieved, time taken to initiate feeds, reasons for not starting/delay in the initiation of feeds, time taken to achieve the prescribed calories, and reasons for interruptions of feeds were collected. Primary outcome analyzed was adequacy of nutrition (>80% prescribed dose), and secondary outcomes analyzed were ventilator days and ICU LOS. RESULTS: A total of 622 MV patients were analyzed. 36.1% of patients were at nutritional risk (mNUTRIC χ5). 89% of patients received EN, and the time taken to start EN in these patients was 10 hours (6-20) (median [IQR]). Only 29.6% of patients achieved nutritional adequacy. Time taken for this was 36 hours (median). On average, patients on MV received 63% (1025 kcal) and 57% (41 g) of their prescribed calories and proteins, respectively. The most common reasons for withholding feeds were airway-related procedures (68.2%) followed by GI intolerance (15%). Frequent interruptions of EN, patients on >1 vasopressors, and surgical admissions were reasons for nutritional inadequacy. Nutritional adequacy had no impact on clinical outcomes. CONCLUSION: Despite following guidelines and feeding protocols, there exists a wide gap between prescribed nutrition and what is actually delivered in MV patients. HOW TO CITE THIS ARTICLE: Kalaiselvan MS, Arunkumar AS, Renuka MK, Sivakumar RL. Nutritional Adequacy in Mechanically Ventilated Patient: Are We Doing Enough? Indian J Crit Care Med 2021;25(2):166-171.

4.
Ophthalmology ; 127(10): 1405-1415, 2020 10.
Article in English | MEDLINE | ID: mdl-32564920

ABSTRACT

PURPOSE: To evaluate the efficacy and safety of intravitreal sirolimus in the management of noninfectious uveitis of the posterior segment (NIU-PS). DESIGN: Combined analysis of 2 phase 3, randomized, double-masked, multinational, 6-month studies. PARTICIPANTS: Adults with active NIU-PS (intermediate uveitis, posterior uveitis, or panuveitis; defined as vitreous haze [VH] ≥1.5+ on modified Standardization of Uveitis Nomenclature scale). METHODS: Patients were randomized 1:1:1 to receive intravitreal sirolimus 44 µg (n = 208), 440 µg (n = 208), or 880 µg (n = 177) on days 1, 60, and 120. Patients discontinued medications for NIU-PS except for systemic corticosteroids, which were tapered according to protocol. Enrollment in the 880-µg group was terminated after interim results found no significant difference in efficacy compared with the 440-µg dose. MAIN OUTCOME MEASURES: The primary efficacy end point was the percentage of patients with VH of 0 at month 5 in the study eye without the use of rescue therapy. Secondary efficacy end points included VH of 0 or 0.5+, corticosteroid-tapering success, and changes in best-corrected visual acuity (BCVA). Safety measures included ocular and nonocular adverse events. RESULTS: A total of 592 patients were randomized. Significantly higher proportions of patients treated with 440 µg compared with 44 µg intravitreal sirolimus achieved VH of 0 (21.2% vs. 13.5%; P = 0.038) and VH of 0 or 0.5+ (50.0% vs. 40.4%; P = 0.049) at month 5. Best-corrected visual acuity was stable (absolute change <5 ETDRS letters) or improved >5 letters in 80.1% and 80.2% of patients in the 440-µg and 44-µg groups, respectively. At month 5, corticosteroids were tapered successfully in 69.6% and 68.8% of patients in the 440-µg and 44-µg groups, and among these patients, VH of 0 or 0.5+ was achieved by 43.5% and 28.1% in the 440-µg and 44-µg groups. Both doses were generally well tolerated. Mean changes from baseline intraocular pressure (IOP) in the study eye at each analysis visit were minimal in all treatment groups. CONCLUSIONS: Intravitreal sirolimus 440 µg improved ocular inflammation, as measured by VH, compared with the 44-µg dose, with minimal impact on IOP, while preserving BCVA.


Subject(s)
Posterior Eye Segment/diagnostic imaging , Sirolimus/administration & dosage , Uveitis, Posterior/drug therapy , Aged , Dose-Response Relationship, Drug , Double-Blind Method , Female , Follow-Up Studies , Humans , Immunosuppressive Agents/administration & dosage , Intraocular Pressure/drug effects , Intravitreal Injections , Male , Tomography, Optical Coherence/methods , Uveitis, Posterior/diagnosis
5.
Environ Monit Assess ; 189(2): 61, 2017 Feb.
Article in English | MEDLINE | ID: mdl-28101739

ABSTRACT

The general public spends a major portion of their time in an indoor environment and hence receives a considerable amount of radiation. Knowledge about indoor radiation is important in order to arrive at the actual effective dose received by residents. The indoor radon, thoron, and progeny concentrations observed in the present study were found to vary with seasons of a given year. The highest and lowest indoor average radon, thoron, and progeny levels were observed during winter and summer seasons, respectively. The concentrations of indoor radon, thoron, and progenies were found to vary with the type of houses. The highest 222Rn, 220Rn, and progeny concentrations were observed in mud houses and the lowest values were recorded in wooden houses. The indoor 222Rn concentration correlated well with concentration of its grandparent 238U in underlying soil with a correlation coefficient of 0.87. The correlation between indoor 220Rn and 232Th in the underlying soil was found to be 0.64. The estimated effective doses received by the general public in the present study due to indoor radon and thoron were 1.49 ± 0.49 and 1.30 ± 0.53 mSv/year, respectively. The annual effective doses due to radon and thoron progenies were estimated as 0.76 ± 0.27 and 0.47 ± 0.23 mSv/year, respectively. The contributions from 222Rn, 220Rn, and corresponding progenies to the annual effective doses received were 37, 32, 19, and 12%, respectively. The general public living in the study area receives an inhalation dose of 4.02 mSv/year due to indoor radon, thoron, and progenies, which were found to be less than the action limit of ICRP 2009.


Subject(s)
Air Pollutants, Radioactive/analysis , Air Pollution, Indoor/analysis , Inhalation Exposure/statistics & numerical data , Radiation Exposure/statistics & numerical data , Radiation Monitoring , Radon/analysis , Air Pollution, Indoor/statistics & numerical data , Housing/statistics & numerical data , Humans , Seasons
6.
Emerg Infect Dis ; 22(2): 192-200, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26812231

ABSTRACT

Trematodes are recognized as a group of emerging parasites in tropical countries. We identified a trematode as a cause of ocular granulomas that developed in children who bathed in ponds or rivers in South India. DNA was isolated from patients' surgically excised granulomas and from the trematode cercariae (larvae) released by the snail Melanoides tuberculata in water in which the children bathed. Real-time and conventional PCRs were performed that targeted ribosomal DNA regions spanning the internal transcribed spacer 2 and 28S sequences of this trematode. The PCR-amplified products were subjected to bidirectional sequencing. Analysis of sequences for the granuloma samples and the trematode cercariae showed maximum sequence similarity with Procerovum varium (family Heterophyidae). Our results confirmed the etiology of the ocular infection, implicating snail vectors as environmental risk factors for ocular parasitosis.


Subject(s)
Eye Infections, Parasitic/epidemiology , Eye Infections, Parasitic/parasitology , Trematoda/genetics , Trematode Infections/epidemiology , Trematode Infections/parasitology , Adolescent , Animals , Base Sequence , Child , DNA, Helminth , Female , Geography , Granuloma/epidemiology , Granuloma/parasitology , Humans , India/epidemiology , Male , Molecular Sequence Data , Sequence Alignment , Sequence Analysis, DNA , Snails/parasitology , Trematoda/classification , Trematoda/isolation & purification
7.
Ophthalmology ; 123(11): 2413-2423, 2016 11.
Article in English | MEDLINE | ID: mdl-27692526

ABSTRACT

PURPOSE: To evaluate the efficacy and safety of intravitreal sirolimus in the treatment of noninfectious uveitis (NIU) of the posterior segment (i.e., posterior, intermediate, or panuveitis). DESIGN: Phase III, randomized, double-masked, active-controlled, 6-month study with intravitreal sirolimus. PARTICIPANTS: Adults with active NIU of the posterior segment (intermediate, posterior, or panuveitis), defined as a vitreous haze (VH) score >1+. Subjects discontinued NIU medications before baseline, except for systemic corticosteroids, which were allowed only for those already receiving them at baseline and were rapidly tapered after baseline per protocol. METHODS: Intravitreal sirolimus assigned 1:1:1 at doses of 44 (active control), 440, or 880 µg, administered on Days 1, 60, and 120. MAIN OUTCOME MEASURES: The primary efficacy outcome was the percentage of subjects with VH 0 response at Month 5 (study eye) without use of rescue therapy. Secondary outcomes at Month 5 were VH 0 or 0.5+ response rate, corticosteroid tapering success rate (i.e., tapering to a prednisone-equivalent dosage of ≤5 mg/day), and changes in best-corrected visual acuity (BCVA). Adverse events during the double-masked treatment period are presented. RESULTS: A total of 347 subjects were randomized. Higher proportions of subjects in the intravitreal sirolimus 440 µg (22.8%; P = 0.025) and 880 µg (16.4%; P = 0.182) groups met the primary end point than in the 44 µg group (10.3%). Likewise, higher proportions of subjects in the 440 µg (52.6%; P = 0.008) and 880 µg (43.1%; P = 0.228) groups achieved a VH score of 0 or 0.5+ than in the 44 µg group (35.0%). Mean BCVA was maintained throughout the study in each dose group, and the majority of subjects receiving corticosteroids at baseline successfully tapered off corticosteroids (44 µg [63.6%], 440 µg [76.9%], and 880 µg [66.7%]). Adverse events in the treatment and active control groups were similar in incidence, and all doses were well tolerated. CONCLUSIONS: Intravitreal sirolimus 440 µg demonstrated a significant improvement in ocular inflammation with preservation of BCVA in subjects with active NIU of the posterior segment.


Subject(s)
Posterior Eye Segment/pathology , Retina/pathology , Sirolimus/administration & dosage , Uveitis/drug therapy , Visual Acuity , Adolescent , Adult , Aged , Aged, 80 and over , Dose-Response Relationship, Drug , Double-Blind Method , Female , Follow-Up Studies , Humans , Immunosuppressive Agents/administration & dosage , Intravitreal Injections , Male , Middle Aged , Retrospective Studies , Time Factors , Tomography, Optical Coherence , Treatment Outcome , Uveitis/diagnosis , Young Adult
8.
Colorectal Dis ; 17(12): 1055-61, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26096269

ABSTRACT

AIM: The UK national bowel cancer awareness campaigns in 2012 were intended to improve survival of patients with colorectal cancer (CRC) by raising public awareness and prompting symptomatic individuals to seek medical attention early. The aim of the present study was to compare the number of CRCs diagnosed, tumour stage at diagnosis, survival and number of investigations performed during the campaigns compared with a similar time period in 2011. METHOD: A retrospective study was carried out of 1439 consecutive referrals through the 2-week wait pathway (2WW) to our colorectal unit during the February and September 2012 campaigns. Patient demographics, number of referrals, investigations performed and newly diagnosed cases of CRC with their respective staging were determined and compared with a group in 2011. Two-year survival was evaluated by Kaplan-Meier statistics. RESULTS: Referrals through the 2WW increased by 55-60% and endoscopic and the number of radiological investigations performed increased by over 70% during the awareness campaigns. Although new diagnoses of CRC nearly doubled, the increase in the patients referred meant the diagnostic yield remained low at 6%. The bowel cancer awareness campaigns did not alter the tumour stage at presentation, as over 50% of patients were diagnosed with Stage 3 and 4 CRC and there was no significant difference in 2-year survival. CONCLUSION: The UK bowel cancer awareness campaigns appear to have improved public awareness of CRC and encouraged symptomatic individuals to seek urgent medical attention. The increase in 2WW referrals has not translated into better survival for symptomatic patients, partly due to the proportion presenting with advanced disease.


Subject(s)
Colorectal Neoplasms/diagnosis , Early Detection of Cancer/statistics & numerical data , Health Promotion/statistics & numerical data , Referral and Consultation/statistics & numerical data , Adult , Aged , Aged, 80 and over , Colorectal Neoplasms/mortality , Colorectal Neoplasms/psychology , Female , Health Knowledge, Attitudes, Practice , Health Promotion/methods , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Retrospective Studies , United Kingdom , Young Adult
9.
ScientificWorldJournal ; 2015: 174512, 2015.
Article in English | MEDLINE | ID: mdl-26759829

ABSTRACT

Wireless Body Area Network (WBAN) is effectively used in healthcare to increase the value of the patient's life and also the value of healthcare services. The biosensor based approach in medical care system makes it difficult to respond to the patients with minimal response time. The medical care unit does not deploy the accessing of ubiquitous broadband connections full time and hence the level of security will not be high always. The security issue also arises in monitoring the user body function records. Most of the systems on the Wireless Body Area Network are not effective in facing the security deployment issues. To access the patient's information with higher security on WBAN, Game Theory with Stackelberg Security Equilibrium (GTSSE) is proposed in this paper. GTSSE mechanism takes all the players into account. The patients are monitored by placing the power position authority initially. The position authority in GTSSE is the organizer and all the other players react to the organizer decision. Based on our proposed approach, experiment has been conducted on factors such as security ratio based on patient's health information, system flexibility level, energy consumption rate, and information loss rate. Stackelberg Security considerably improves the strength of solution with higher security.


Subject(s)
Remote Sensing Technology/methods , Telemedicine/methods , Game Theory
10.
ScientificWorldJournal ; 2015: 786497, 2015.
Article in English | MEDLINE | ID: mdl-26000337

ABSTRACT

Bioinformatics and genomic signal processing use computational techniques to solve various biological problems. They aim to study the information allied with genetic materials such as the deoxyribonucleic acid (DNA), the ribonucleic acid (RNA), and the proteins. Fast and precise identification of the protein coding regions in DNA sequence is one of the most important tasks in analysis. Existing digital signal processing (DSP) methods provide less accurate and computationally complex solution with greater background noise. Hence, improvements in accuracy, computational complexity, and reduction in background noise are essential in identification of the protein coding regions in the DNA sequences. In this paper, a new DSP based method is introduced to detect the protein coding regions in DNA sequences. Here, the DNA sequences are converted into numeric sequences using electron ion interaction potential (EIIP) representation. Then discrete wavelet transformation is taken. Absolute value of the energy is found followed by proper threshold. The test is conducted using the data bases available in the National Centre for Biotechnology Information (NCBI) site. The comparative analysis is done and it ensures the efficiency of the proposed system.


Subject(s)
Algorithms , Computational Biology/methods , Sequence Analysis, DNA/methods , Computer Simulation , Exons , Genomics/methods , Humans , Open Reading Frames , Reproducibility of Results , Wavelet Analysis
11.
Ophthalmology ; 121(8): 1643-8, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24697913

ABSTRACT

PURPOSE: To evaluate the reliability of clinical grading of vitreous haze using a new 9-step ordinal scale versus the existing 6-step ordinal scale. DESIGN: Evaluation of diagnostic test (interobserver agreement study). PARTICIPANTS: A total of 119 consecutive patients (204 uveitic eyes) presenting for uveitis subspecialty care on the study day at 1 of 3 large uveitis centers. METHODS: Five pairs of uveitis specialists clinically graded vitreous haze in the same eyes, one after the other using the same equipment, using the 6- and 9-step scales. MAIN OUTCOME MEASURES: Agreement in vitreous haze grade between each pair of specialists was evaluated by the κ statistic (exact agreement and agreement within 1 or 2 grades). RESULTS: The scales correlated well (Spearman's ρ = 0.84). Exact agreement was modest using both the 6-step and 9-step scales: average κ = 0.46 (range, 0.28-0.81) and κ = 0.40 (range, 0.15-0.63), respectively. Within 1-grade agreement was slightly more favorable for the scale with fewer steps, but values were excellent for both scales: κ = 0.75 (range, 0.66-0.96) and κ = 0.62 (range, 0.38-0.87), respectively. Within 2-grade agreement for the 9-step scale also was excellent (κ = 0.85; range, 0.79-0.92). Two-fold more cases were potentially clinical trial eligible on the basis of the 9-step than the 6-step scale (P<0.001). CONCLUSIONS: Both scales are sufficiently reproducible using clinical grading for clinical and research use with the appropriate threshold (≥ 2- and ≥ 3-step differences for the 6- and 9-step scales, respectively). The results suggest that more eyes are likely to meet eligibility criteria for trials using the 9-step scale. The 9-step scale appears to have higher reproducibility with Reading Center grading than clinical grading, suggesting that Reading Center grading may be preferable for clinical trials.


Subject(s)
Diagnostic Techniques, Ophthalmological , Eye Diseases/classification , Uveitis/classification , Vitreous Body/pathology , Cross-Sectional Studies , Humans , Observer Variation , Reproducibility of Results , Sickness Impact Profile
12.
Ophthalmology ; 121(10): 1863-70, 2014 Oct.
Article in English | MEDLINE | ID: mdl-24917273

ABSTRACT

OBJECTIVE: To compare the relative effectiveness of methotrexate and mycophenolate mofetil for noninfectious intermediate uveitis, posterior uveitis, or panuveitis. DESIGN: Multicenter, block-randomized, observer-masked clinical trial. PARTICIPANTS: Eighty patients with noninfectious intermediate, posterior, or panuveitis requiring corticosteroid-sparing therapy at Aravind Eye Hospitals in Madurai and Coimbatore, India. INTERVENTION: Patients were randomized to receive 25 mg weekly oral methotrexate or 1 g twice daily oral mycophenolate mofetil and were monitored monthly for 6 months. Oral prednisone and topical corticosteroids were tapered. MAIN OUTCOME MEASURES: Masked examiners assessed the primary outcome of treatment success, defined by achieving the following at 5 and 6 months: (1) ≤0.5+ anterior chamber cells, ≤0.5+ vitreous cells, ≤0.5+ vitreous haze and no active retinal/choroidal lesions in both eyes, (2) ≤10 mg of prednisone and ≤2 drops of prednisolone acetate 1% a day, and (3) no declaration of treatment failure because of intolerability or safety. Additional outcomes included time to sustained corticosteroid-sparing control of inflammation, change in best spectacle-corrected visual acuity, resolution of macular edema, adverse events, subgroup analysis by anatomic location, and medication adherence. RESULTS: Forty-one patients were randomized to methotrexate and 39 to mycophenolate mofetil. A total of 67 patients (35 methotrexate, 32 mycophenolate mofetil) contributed to the primary outcome. Sixty-nine percent of patients achieved treatment success with methotrexate and 47% with mycophenolate mofetil (P = 0.09). Treatment failure from adverse events or tolerability was not different by treatment arm (P = 0.99). There were no differences between treatment groups in time to corticosteroid-sparing control of inflammation (P = 0.44), change in best spectacle-corrected visual acuity (P = 0.68), or resolution of macular edema (P = 0.31). CONCLUSIONS: There was no statistically significant difference in corticosteroid-sparing control of inflammation between patients receiving methotrexate or mycophenolate mofetil. However, there was a 22% difference in treatment success favoring methotrexate.


Subject(s)
Immunosuppressive Agents/therapeutic use , Methotrexate/therapeutic use , Mycophenolic Acid/analogs & derivatives , Uveitis/drug therapy , Administration, Oral , Adult , Female , Humans , Immunosuppressive Agents/adverse effects , Macular Edema/drug therapy , Male , Methotrexate/adverse effects , Middle Aged , Mycophenolic Acid/adverse effects , Mycophenolic Acid/therapeutic use , Visual Acuity , Young Adult
13.
Acc Chem Res ; 46(8): 1720-30, 2013 Aug 20.
Article in English | MEDLINE | ID: mdl-23634641

ABSTRACT

Metal nanoparticles contain the active sites in heterogeneous catalysts, which are important for many industrial applications including the production of clean fuels, chemicals and pharmaceuticals, and the cleanup of exhaust from automobiles and stationary power plants. Sintering, or thermal deactivation, is an important mechanism for the loss of catalyst activity. This is especially true for high temperature catalytic processes, such as steam reforming, automotive exhaust treatment, or catalytic combustion. With dwindling supplies of precious metals and increasing demand, fundamental understanding of catalyst sintering is very important for achieving clean energy and a clean environment, and for efficient chemical conversion processes with atom selectivity. Scientists have proposed two mechanisms for sintering of nanoparticles: particle migration and coalescence (PMC) and Ostwald ripening (OR). PMC involves the mobility of particles in a Brownian-like motion on the support surface, with subsequent coalescence leading to nanoparticle growth. In contrast, OR involves the migration of adatoms or mobile molecular species, driven by differences in free energy and local adatom concentrations on the support surface. In this Account, we divide the process of sintering into three phases. Phase I involves rapid loss in catalyst activity (or surface area), phase II is where sintering slows down, and phase III is where the catalyst may reach a stable performance. Much of the previous work is based on inferences from catalysts that were observed before and after long term treatments. While the general phenomena can be captured correctly, the mechanisms cannot be determined. Advancements in the techniques of in situ TEM allow us to observe catalysts at elevated temperatures under working conditions. We review recent evidence obtained via in situ methods to determine the relative importance of PMC and OR in each of these phases of catalyst sintering. The evidence suggests that, in phase I, OR is responsible for the rapid loss of activity that occurs when particles are very small. Surprisingly, very little PMC is observed in this phase. Instead, the rapid loss of activity is caused by the disappearance of the smallest particles. These findings are in good agreement with representative atomistic simulations of sintering. In phase II, sintering slows down since the smallest particles have disappeared. We now see a combination of PMC and OR, but do not fully understand the relative contribution of each of these processes to the overall rates of sintering. In phase III, the particles have grown large and other parasitic phenomena, such as support restructuring, can become important, especially at high temperatures. Examining the evolution of particle size and surface area with time, we do not see a stable or equilibrium state, especially for catalysts operating at elevated temperatures. In conclusion, the recent literature, especially on in situ studies, shows that OR is the dominant process causing the growth of nanoparticle size. Consequently, this leads to the loss of surface area and activity. While particle migration could be controlled through suitable structuring of catalyst supports, it is more difficult to control the mobility of atomically dispersed species. These insights into the mechanisms of sintering could help to develop sinter-resistant catalysts, with the ultimate goal of designing catalysts that are self-healing.


Subject(s)
Metal Nanoparticles/chemistry , Catalysis , Particle Size , Surface Properties , Temperature
14.
Acta Crystallogr Sect E Struct Rep Online ; 70(Pt 10): 199-202, 2014 Oct 01.
Article in English | MEDLINE | ID: mdl-25484651

ABSTRACT

In the title compounds, C27H28N2O3, (I), and C28H30N2O3, (II), the conformation about the C=N bond is E. The piperidine rings adopt chair conformations with the attached phenyl rings almost normal to their mean planes, the dihedral angles being 85.82 (8) and 85.84 (7)° in (I), and 87.98 (12) and 86.42 (13)° in (II). The phenyl rings are inclined to one another by 52.87 (8)° in (I) and by 60.51 (14)° in (II). The main difference in the conformation of the two compounds is the angle of inclination of the phen-oxy-carbonyl ring to the piperidine ring mean plane. In (I), these two planes are almost coplanar, with a dihedral angle of 2.05 (8)°, while in (II), this angle is 45.24 (13)°. In the crystal of (I), mol-ecules are linked by C-H⋯O hydrogen bonds, forming inversion dimers with R 2 (2)(14) loops. The dimers are linked via C-H⋯π inter-actions forming a three-dimensional network. In the crystal of (II), there are no significant inter-molecular inter-actions present.

15.
Acta Crystallogr Sect E Struct Rep Online ; 70(Pt 5): o551, 2014 May 01.
Article in English | MEDLINE | ID: mdl-24860359

ABSTRACT

In the title compound, C27H29N3O2, the piperidine ring exists in a chair conformation with an equatorial orientation of the phenyl and methyl substituents. The C-C=N bond angles are significantly different [119.1 (2) and 127.2 (2)°]. The phenyl rings are inclined to one another by 44.90 (14)°, and by 80.85 (13) and 79.62 (12)° to the mean plane of the piperidine ring. The terminal pyridine ring is inclined to the piperidine ring mean plane by 74.79 (15)°. In the crystal, mol-ecules are linked by C-H⋯π inter-actions, forming a three-dimensional network.

16.
Acta Crystallogr Sect E Struct Rep Online ; 70(Pt 6): o713, 2014 Jun 01.
Article in English | MEDLINE | ID: mdl-24940283

ABSTRACT

The title piperidine derivative, C26H26N2O3, has an E conformation about the N=C bond. The piperidine ring has a chair conformation and its mean plane is almost perpendicular to the attached phenyl rings, making dihedral angles of 87.47 (9) and 87.34 (8)°. The planes of these two phenyl rings are inclined to one another by 60.38 (9)°. The plane of the terminal phenyl ring is tilted at an angle of 32.79 (9)° to the mean plane of the piperidine ring. The mol-ecular conformation is stabilized by two intra-molecular C-H⋯O contacts. There are no significant inter-molecular inter-actions in the crystal.

17.
Sci Rep ; 14(1): 6290, 2024 03 15.
Article in English | MEDLINE | ID: mdl-38491186

ABSTRACT

BC (Breast cancer) is the second most common reason for women to die from cancer. Recent workintroduced a model for BC classifications where input breast images were pre-processed using median filters for reducing noises. Weighed KMC (K-Means clustering) is used to segment the ROI (Region of Interest) after the input image has been cleaned of noise. Block-based CDF (Centre Distance Function) and CDTM (Diagonal Texture Matrix)-based texture and shape descriptors are utilized for feature extraction. The collected features are reduced in counts using KPCA (Kernel Principal Component Analysis). The appropriate feature selection is computed using ICSO (Improved Cuckoo Search Optimization). The MRNN ((Modified Recurrent Neural Network)) values are then improved through optimization before being utilized to divide British Columbia into benign and malignant types. However, ICSO has many disadvantages, such as slow search speed and low convergence accuracy and training an MRNN is a completely tough task. To avoid those problems in this work preprocessing is done by bilateral filtering to remove the noise from the input image. Bilateral filter using linear Gaussian for smoothing. Contrast stretching is applied to improve the image quality. ROI segmentation is calculated based on MFCM (modified fuzzy C means) clustering. CDTM-based, CDF-based color histogram and shape description methods are applied for feature extraction. It summarizes two important pieces of information about an object such as the colors present in the image, and the relative proportion of each color in the given image. After the features are extracted, KPCA is used to reduce the size. Feature selection was performed using MCSO (Mutational Chicken Flock Optimization). Finally, BC detection and classification were performed using FCNN (Fuzzy Convolutional Neural Network) and its parameters were optimized using MCSO. The proposed model is evaluated for accuracy, recall, f-measure and accuracy. This work's experimental results achieve high values of accuracy when compared to other existing models.


Subject(s)
Algorithms , Breast Neoplasms , Female , Humans , Breast Neoplasms/diagnostic imaging , Image Processing, Computer-Assisted/methods , Neural Networks, Computer , British Columbia
18.
Int J Biol Macromol ; 273(Pt 1): 132954, 2024 Jun 07.
Article in English | MEDLINE | ID: mdl-38852726

ABSTRACT

This study explores the potential of liposome encapsulated silica immobilized cytochrome P450 monooxygenase (LSICY) for bioremediation of mercury (Hg2+). Current limitations in Hg2+ reduction, including sensitivity to factors like pH and cost, necessitate alternative methods. We propose LSICY as a solution, leveraging the enzymatic activities of cytochrome P450 monooxygenase (CYPM) for Hg2+ reduction through hydroxylation and oxygenation. Our investigation employs LSICY to assess its efficacy in mitigating Hg2+ toxicity in Oryza sativa (rice) plants. Gas chromatography confirmed gibberellic acid (GA) presence in the Hg2+ reducing bacteria Priestia megaterium RP1 (PMRP1), highlighting a potential link between CYP450 activity and plant health. This study demonstrates the promise of LSICY as a sustainable and effective approach for Hg2+ bioremediation, promoting a safer soil environment.

19.
Am J Ophthalmol ; 2024 Jun 21.
Article in English | MEDLINE | ID: mdl-38909740

ABSTRACT

PURPOSE: To compare the effectiveness of methotrexate (MTX) and mycophenolate mofetil (MMF) in achieving corticosteroid-sparing control of uveitis in patients with Vogt-Koyanagi-Harada (VKH) disease. METHODS: A subanalysis of patients with VKH from the First-line Antimetabolites as Steroid-sparing Treatment (FAST) Uveitis Trial, a randomized, observer-masked, comparative effectiveness trial, with comparisons by treatment (MTX versus MMF) and disease stage (acute versus chronic). Individuals with noninfectious uveitis were placed on a standardized corticosteroid taper and block randomized 1:1 to either 25mg weekly oral MTX or 1.5g twice daily oral MMF. The primary outcome was treatment success defined by corticosteroid-sparing control of uveitis at 6 months. Additional outcomes included change in best spectacle-corrected visual acuity (BSCVA), retinal central subfield thickness (CST), and resolution of serous retinal detachment (SRD). RESULTS: Ninety-three out of 216 enrolled patients had VKH; 49 patients were randomized to MTX and 44 to MMF, of which 85 patients (46 on MTX, 39 on MMF) contributed to the primary outcome. There was no significant difference in treatment success by antimetabolite (80.4% for MTX compared to 64.1% for MMF; P=.12) or in BSCVA improvement (P=.78). Methotrexate was superior to MMF in reducing CST (P=.003) and resolving SRD (P=.02). There was no significant difference in treatment success by disease stage (P=.25), but patients with acute VKH had greater improvement in BSCVA (P<.001) and reduction of CST (P=.02) than chronic VKH patients. CONCLUSIONS: MTX and MMF have comparable outcomes as corticosteroid-sparing immunosuppressive therapies for VKH. Visual acuity improvement was greater in acute vs chronic VKH. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00182929.

20.
Indian J Med Res ; 138: 129-34, 2013.
Article in English | MEDLINE | ID: mdl-24056567

ABSTRACT

BACKGROUND & OBJECTIVES: In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, this study was undertaken to assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate and methanol solvent extracts from the medicinal plant Pithecellobium dulce against the mosquito vectors, Anopheles stephensi and Aedes aegypti (Diptera: Culicidae). METHODS: Larvicidal activity of P. dulce plant extracts was studied in the range of 60 to 450 mg/l against early third instar larvae of An. stephensi and Ae. aegypti in the laboratory. The larval mortality was observed after 24 h of exposure. The ovicidal activity was determined against An. stephensi and Ae. aegypti to various concentrations ranging from 100 to 750 mg/l under the laboratory conditions. Mean per cent hatchability of the eggs were observed after 48 h post treatment. RESULTS: All leaf and seed extracts showed moderate larvicidal and ovicidal effects; however, the highest larval mortality was found in methanol extract of leaf of P. dulce against the larvae of An. stephensi and Ae. aegypti with the LC50 and LC90 values 145.43, 155.78 mg/l and 251.23, 279.73 mg/l, respectively. The per cent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. Zero hatchability was observed at 400 mg/l for leaf methanol extract and 625 mg/l for seed methanol extract of P. dulce against An. stephensi and Ae. aegypti, respectively. Compared to leaf extracts, seed extracts have low potency against the two mosquitoes. INTERPRETATION & CONCLUSIONS: The present results suggest that the leaf and seed extracts of P. dulce have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes.


Subject(s)
Aedes , Anopheles , Culicidae/physiology , Fabaceae/physiology , Pest Control, Biological , Aedes/growth & development , Animals , Anopheles/growth & development , Larva/growth & development
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