Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 255
Filter
1.
Semina cienc. biol. saude ; 45(1): 35-44, jan./jun. 2024. tab; ilus
Article in Portuguese | LILACS | ID: biblio-1554878

ABSTRACT

O aplicativo móvel CalcVAN foi desenvolvido para auxiliar os profissionais de saúde para otimizar as doses de vancomicina em pacientes hospitalizados. Porém, é imprescindível avaliar a sua usabilidade antes de disponibilizá-lo para prática clínica. Assim, o objetivo do estudo é avaliar a usabilidade do aplicativo móvel na perspectiva dos profissionais de saúde. Trata-se de um estudo descritivo, de avaliação heurística da usabilidade de um aplicativo móvel. Foram convidados profissionais da área de saúde com expertise no tema de gerenciamento de antimicrobianos e vancomicina. O instrumento validado Smartphone Usability questionnaiRE (SURE) foi utilizado para mensuração da usabilidade por meio de um questionário on-line. Vinte e um especialistas participaram do estudo, com média de idade de 32,6 anos, sendo a maioria de mulheres (n = 14, 66,7%), profissionais farmacêuticos (n = 13, 61,9%), com pós-graduação lato sensu (n = 10, 47,6%), que trabalhavam em hospitais públicos ou privados (n = 15, 71,4%) e com média de experiência em 9,7 anos. Com base na interpretação dos resultados obtidos pelo instrumento SURE, a média de usabilidade geral do CalcVAN foi de 83 pontos, com escore menor de 78 e maior de 90 pontos. O teste de usabilidade foi enquadrado nos dois últimos níveis, 70 e 80, onde os profissionais de saúde passaram a concordar fortemente e totalmente, indicando que o aplicativo móvel apresenta uma usabilidade satisfatória. O CalcVAN atingiu uma usabilidade satisfatória e atende as necessidades e exigências dos profissionais de saúde, mostrando--se eficiente para realizar as funções propostas.


The CalcVAN app was developed to assist healthcare professionals in optimizing vancomycin doses for hospitalized patients. However, the usability test before making it available for clinical practice is essential. Therefore, the study aims to evaluate the usability of the app from the perspective of health professionals. A descriptive study, a heuristic evaluation of the usability of a mobile application was conducted. Healthcare professionals with expertise in antimicrobial management and vancomycin were invited to participate. The validated Smartphone Usability questionnaiRE (SURE) was used to measure usability through an online questionnaire. Twenty-one experts participated in the study, with a mean age of 32.6 years, mostly of them women (n = 14, 66.7%), pharmacists (n = 13, 61.9%), with postgraduate education (n = 10, 47.6%), working in private or public hospitals (n = 15, 71.4%), and a mean experience of 9.7 years. Overall usability score for CalcVAN was 83 points, ranging from a minimum of 78 to a maximum of 90 points. The usability test registered within the last two levels, 70 and 80, with users expressing strongly and fully agreed, indicating that the app demonstrates satisfactory usability. CalcVAN achieved satisfactory usability, fulfilling the needs and requirements of health professionals, proving to be efficient in performing the intended functions.


Subject(s)
Humans , Male , Female , Adult
2.
International Eye Science ; (12): 641-645, 2024.
Article in Chinese | WPRIM | ID: wpr-1012836

ABSTRACT

AIM: To evaluate the accuracy of the formulas, including Haigis, SRK/T, Holladay 1, and Holladay 2, in predicting the diopter of the intraocular lens implanted in high myopia cataract patients.METHODS: Prospective study. A total of 168 cases(168 eyes)of age-related cataract with an axial length(AL)≥26 mm who were treated in our hospital from August 2017 to November 2021 were selected. According to the preoperative AL measured by IOL Master 700, the patients were divided into five groups, including 37 cases(37 eyes)in group A with 26 mm≤AL<27 mm, 34 cases(34 eyes)in group B with 27 mm≤AL<28 mm, 42 cases(42 eyes)in group C with 28 mm≤AL<29 mm, 28 cases(28 eyes)in group D with 29 mm≤AL<30 mm, and 27 patients(27 eyes)in group E with AL ≥ 30 mm. Subjective refraction was performed at 3 mo postoperatively, and the mean numerical error(MNE)and mean absolute error(MAE)of each formula for predicting diopters were calculated.RESULTS: The MNE and MAE of the Haigis and Holladay 2 formulas were relatively less in each group, and MNE and MAE did not significantly increase with the growth of the axial length. However, the MAE and MNE of the SRK/T and Holladay 1 formulas significantly increased with the growth of the axial length, with the MNE and MAE of the Holladay 1 formula increasing more significantly in groups C, D, and E.CONCLUSION: For patients with age-related cataract, with an axial length of ≥26 mm, the accuracy of predicting the diopter of the intraocular lens using the Haigis and Holladay 2 formulas were higher.

3.
Neuroscience Bulletin ; (6): 50-64, 2024.
Article in English | WPRIM | ID: wpr-1010668

ABSTRACT

The organization of the brain follows a topological hierarchy that changes dynamically during development. However, it remains unknown whether and how cognitive training administered over multiple years during development can modify this hierarchical topology. By measuring the brain and behavior of school children who had carried out abacus-based mental calculation (AMC) training for five years (starting from 7 years to 12 years old) in pre-training and post-training, we revealed the reshaping effect of long-term AMC intervention during development on the brain hierarchical topology. We observed the development-induced emergence of the default network, AMC training-promoted shifting, and regional changes in cortical gradients. Moreover, the training-induced gradient changes were located in visual and somatomotor areas in association with the visuospatial/motor-imagery strategy. We found that gradient-based features can predict the math ability within groups. Our findings provide novel insights into the dynamic nature of network recruitment impacted by long-term cognitive training during development.


Subject(s)
Child , Humans , Cognitive Training , Magnetic Resonance Imaging , Brain , Brain Mapping , Motor Cortex
4.
Indian J Ophthalmol ; 2023 May; 71(5): 2139-2142
Article | IMSEAR | ID: sea-225038

ABSTRACT

Purpose: The ideal formula for intraocular lens (IOL) power calculation following cataract surgery in pediatric eyes till date has no answer. We compared the predictability of the Sanders–Retzlaff–Kraff (SRK) II and the Barrett Universal (BU) II formula and the effect of axial length, keratometry, and age. Methods: This was a retrospective analysis of children who were under eight years of age and who underwent cataract surgery with IOL implantation under general anesthesia between September 2018 and July 2019. The prediction error of SRK II formula was calculated by subtracting the target refraction and the actual postoperative spherical equivalent. Preoperative biometry values were used to calculate the IOL power using the BU II formula with the same target refraction that was used in SRK II. The predicted spherical equivalent of the BU II formula was then back?calculated using the SRK II formula with the IOL power obtained with the BU II formula. The prediction errors of the two formulae were compared for statistical significance. Results: Seventy?two eyes of 39 patients were included in the study. The mean age at surgery was 3.8 ± 2 years. The mean axial length was 22.1 ± 1.5 mm, and the mean keratometry was 44.7 ± 1.7 D. The group with an axial length >24 mm showed a significant and strong positive correlation (r = 0.93, P = 0) on comparison mean absolute prediction errors using the SRK II formula. There was a strong negative correlation between the mean prediction error in the overall keratometry group using the BU II formula (r = ?0.72, P < 0.000). There was no significant correlation between age and refractive accuracy using the two formulae in any of the subgroups of age. Conclusion: There is no perfect answer to an ideal formula for IOL calculation in children. IOL formulae need to be chosen keeping in mind the varying ocular parameters.

5.
Indian J Ophthalmol ; 2023 Mar; 71(3): 1025-1026
Article | IMSEAR | ID: sea-224921

ABSTRACT

In this era of cutting-edge research and digitalization, artificial intelligence (AI) has rapidly penetrated all subspecialties, including ophthalmology. Managing AI data and analytics is cumbersome, and implementing blockchain technology has made this task less challenging. Blockchain technology is an advanced mechanism with a robust database that allows the unambiguous sharing of widespread information within a business model or network. The data is stored in blocks that are linked together in chains. Since its inception in 2008, blockchain technology has grown over the years, and its novel use in ophthalmology has been less well documented. This section on current ophthalmology discusses the novel use and future of blockchain technology for intraocular lens power calculation and refractive surgery workup, ophthalmic genetics, payment methods, international data documentation, retinal images, global myopia pandemic, virtual pharmacy, and drug compliance and treatment. The authors have also provided valuable insights into various terminologies and definitions used in blockchain technology.

6.
Indian J Ophthalmol ; 2023 Feb; 71(2): 541-546
Article | IMSEAR | ID: sea-224842

ABSTRACT

Purpose: To evaluate a method using measured values of total corneal refractive power (TCRP) for a manufacturer’s online calculator by comparing it with the Barrett toric calculator (BTC) and Kane toric calculator (KTC) combined with simulated keratometry values (SimK). Methods: This was a retrospective case series. Patient records were reviewed to identify the patients who had biometry with the IOL Master 700 and Pentacam recorded before toric IOL implantation and refractive follow?up data after implantation. The predicted error in residual astigmatism was calculated by vector analysis according to the calculation methods and the measurements used. Results: A total of 70 eyes of 56 patients were included. The mean absolute astigmatism prediction errors were 0.6 ± 0.32, 0.59 ± 0.35, and 0.61 ± 0.35 D for the ATCTCRP, BTCSimK, and KTCSimK calculators, respectively (P = 0.934), and the centroid of the prediction errors were 0.3 D @ 178°, 0.11 D @ 102°, and 0.09 D @ 147°, respectively (P = 0.23). In the with?the?rule subgroup, the centroid of the prediction error was 0.34 D @ 176° for ATCTCRP and was the highest among the three calculation methods (P = 0.046). Conclusion: The ATCTCRP, BTCSimK, and KTCSimK calculators had similar performance with regards to their astigmatism prediction accuracy. The ATCTCRP calculator combined with 4.0?mm apex/ ring readings of TCRP was slightly intended to result in against?the?rule residual astigmatism.

7.
Chinese Journal of General Surgery ; (12): 611-615, 2023.
Article in Chinese | WPRIM | ID: wpr-994606

ABSTRACT

Objective:To evaluate the efficacy and safety of of rivaroxaban for different doses in the treatment of isolated distal deep vein thrombosis.Methods:The clinical data of 853 patients of isolated distal deep vein thrombosis attending Nanjing Drum Tower Hospital from Jan 2018 to Dec 2020 was retrospectively analyzed.Results:Thrombotic recurrence rate increased with increasing follow-up in the standard and low dose groups, and it was significantly lower in the standard dose group than in the low dose group (HR=0.44, 95% CI: 0.25-0.78, P=0.005) with most thrombosis occurring within the first year of follow-up. There was no statistical difference between the two groups in terms of major bleeding events (HR=1.70,95%CI 0.56-5.14, P=0.530) and the incidence of clinically relevant non-major bleeding events was significantly higher in the standard dose group than in the low dose group (HR=2.36, 95%CI 1.26-4.44, P=0.020). Subgroup analysis on anticoagulation duration found when anticoagulation duration was longer than 1.5 months, the risk of thrombosis was lower in the standard dose group than the low dose group (1.5-3 months:HR=0.11, 95%CI 0.01-0.87, >3 months: HR=0.19, 95%CI 0.04-0.95), there was an interaction between anticoagulation duration and dose ( P=0.007). Conclusions:Based on the risk of thrombosis recurrence and bleeding events, the standard dose of rivaroxaban (20 mg qd) is recommended for patients with isolated distal deep vein thrombosis, and the anticoagulant duration should be maintained for 1.5 months or more.

8.
Chinese Journal of Radiation Oncology ; (6): 539-545, 2023.
Article in Chinese | WPRIM | ID: wpr-993227

ABSTRACT

Objective:To evaluate the dose calculation accuracy of cone-beam CT (CBCT) image by actual measurement method.Methods:CBCT images of 60 patients in the Second Affiliated Hospital of Soochow University from September, 2021 to May, 2022 were retrospectively analyzed. CBCT images of full-fan and half-fan scanning of the head, half-fan scanning of the chest and pelvis were obtained by the Varian OBI system. Hounsfield unit - electron density (HU-ED) curves corresponding to the scanning conditions were established with CIRS electron density phantom. The radiotherapy plans were designed on the CBCT images, and the dose calculation results of the detection point were compared with the ionization chamber measurement results to analyze the dose error. Then, three-dimensional dose verification system was adopted to detect the accuracy of the CBCT image radiotherapy plans implementation process in 60 patients, and the accuracy of dose calculation was verified according to the D 99%, D mean, D 1% of target volume, D mean and D 1% of organs at risk (OAR), and the γ pass rate. Results:In point dose detection in phantom, the dose calculation errors of CBCT images in the above four scanning patterns were -1.06%±0.87%、-1.67%±0.86%, 0.91%±0.73%, -1.54%±0.90%, respectively. In dosimetric verification based on patients' CBCT image treatment plan, the mean difference of D mean, D 99%, and D 1% of planning target volume (PTV) in all scanning modes were not higher than 2%, and the D mean and D 1% differences of other OAR were not higher than 3%, except for the lens of patients in the head. The average γ values of target volume and OAR were less than 0.5 under the criteria of 3%/2 mm. Conclusions:Under the condition of correctly establishing HU-ED curves, intensity-modulated radiation therapy (IMRT) / volumetric-modulated arc therapy (VMAT) planning based on CBCT images can be employed to estimate and monitor the actual dose to target volume and OAR in adaptive radiotherapy. Full-fan scanning patterns can further improve the accuracy of dose calculation for the head of patients.

9.
Chinese Journal of Radiation Oncology ; (6): 375-378, 2023.
Article in Chinese | WPRIM | ID: wpr-993203

ABSTRACT

Deterministic method is a numerical calculation method based on photon-electron coupled transport with high computational accuracy and speed, which has been widely applied in photon radiotherapy dose calculation in recent years. However, this method has been introduced into radiotherapy for only a short period of time, which has been rarely studied in China, and systematic understanding of its characteristics is still lacking. In this article, the principles of deterministic method, current development state and clinical application were reviewed, aiming to provide reference for carrying out relevant research.

10.
Chinese Journal of Experimental Ophthalmology ; (12): 598-602, 2023.
Article in Chinese | WPRIM | ID: wpr-990887

ABSTRACT

Cataract extraction is often combined with the implantation of intraocular lens (IOL) with the diopter matching the operated eye to restore optimal visual function after surgery.However, there are often errors between the actual refractive power of the operated eye and the predicted value.One of the major causes of postoperative refractive error is the change in IOL position compared with the expected position.In order to improve the accuracy of postoperative refraction prediction, Holladay proposed to introduce the concept of effective lens position (ELP) into the IOL diopter calculation formula.The differences in the parameters and algorithms incorporated in the calculation of ELP lead to differences in the accuracy of IOL calculation formulas.With the application of multi-parameter calculation methods, especially the formula based on the artificial intelligence algorithm, the accuracy of IOL calculation formula has been significantly improved.ELP is also affected by various factors such as differences in ocular anatomy, IOL design and material, and surgical procedures, especially the factors affecting the stability of the capsular bag that increase the difficulty of accurately predicting ELP.Therefore, the changes in postoperative ELP need to be further discussed in order to obtain more accurate postoperative refraction.This article aimed to give a review of the development of calculation formulas and the influencing factors of ELP.

11.
International Eye Science ; (12): 462-465, 2023.
Article in Chinese | WPRIM | ID: wpr-964249

ABSTRACT

AIM: To evaluate the accuracy of SRK/T, Haigis, Barrett Universal II and Wang-Koch modified SRK/T formula in the operation of cataract complicated by super-high myopia.METHODS: A total of 44 cases(52 eyes)with super-high myopia complicated with cataract who underwent phacoemulsification with tension ring implantation combined with intraocular lens implantation in our hospital from January 2020 to June 2021 were collected. SRK/T, Haigis, Barrett Universal Ⅱ formula and Wang-Koch modified SRK/T formula were used to calculate the postoperative reserved diopter before surgery, and the actual diopter was measured by comprehensive optometry at 3mo after surgery. The mean absolute refractive error(MAE)of four formulas was obtained to evaluate the accuracy of the calculation formula.RESULTS: The MAE of SRK/T formula, Haigis formula, Barrett Universal Ⅱ formula and Wang-Koch modified SRK/T formula were 0.86(0.56, 1.20), 0.79(0.56, 1.16), 0.68(0.30, 0.87), 0.65(0.43, 0.75)D, respectively, and MAE of SRK/T formula and Haigis formula were significantly higher than those of Barrett Universal Ⅱ formula and Wang-Koch modified SRK/T formula(P<0.01). According to preoperative corneal curvature(K), enrolled patients were divided into K >46D group(12 eyes), 44D< K ≤46D group(24 eyes), and K ≤44D group(16 eyes). The MAE of SRK/T formula and Haigis formula were significantly higher than those of Barrett Universal Ⅱ formula and Wang-Koch modified SRK/T formula in the three groups(P<0.01). According to preoperative axial length(AL), patients were divided into AL ≤30 mm group(24 eyes)and AL >30mm group(28 eyes). The MAE of SRK/T formula and Haigis formula in two groups were significantly higher than those of Barrett Universal Ⅱ formula and Wang-Koch modified SRK/T formula(P<0.05).CONCLUSIONS: Wang-Koch modified SRK/T formula and Barrett Universal Ⅱ formula are more accurate in predicting the degree of intraocular lens in patients with super-high myopia complicated with cataract.

12.
International Eye Science ; (12): 1568-1572, 2023.
Article in Chinese | WPRIM | ID: wpr-980555

ABSTRACT

AIM: To compare the accuracy of different intraocular lens(IOL)calculation formulas in cataract patients with axial length longer than 28mm and a history of radial keratotomy(RK).METHODS: Retrospective study. The medical records of 19 cataract patients(29 eyes)after RK and with axial length longer than 28mm who underwent cataract surgery from January 2011 to July 2020 in Beijing Tongren Hospital were analyzed. The absolute error(AE)of the difference among three different formulas was calculated. AE refers to the absolute value between the actual spherical equivalent after cataract surgery and the spherical equivalent predicted by the IOL formula. The AE values of the three formulas and the percentages of eyes with AE≤0.5, 0.75, 1.0, and 2.0D were calculated and compared.RESULTS: The AE values of the three formulas were significantly different(χ2=8.759, P=0.013). The Barrett True-K formula had the smallest median AE, which was only 0.62(0.20, 1.15)D, followed by the Haigis formula 0.76(0.34, 1.26)D, and the Holladay 1(D-K)formula had the largest 1.01(0.49, 1.62)D. The percentages of affected eyes with AE ≤0.5, 0.75, 1.0, and 2.0D for the Barrett True-K formula were 48%, 59%, 69%, and 93%, which were equal to or higher than the other two formulas.CONCLUSION: The Barrett True-K formula is more recommended among the three formulas for cataract patients after RK and with axial length longer than 28 mm.

13.
International Eye Science ; (12): 928-932, 2023.
Article in Chinese | WPRIM | ID: wpr-973779

ABSTRACT

Glaucoma and cataracts are the leading causes of blindness, and surgery is an important treatment option. Patients with glaucoma have clinical characteristics such as high intraocular pressure, shallow anterior chamber and short axial length, and the ocular structure is often altered after anti-glaucoma surgery like trabeculectomy. These changes also lead to differences in the accuracy of intraocular lens(IOL)refractive calculation between cataract surgery after anti-glaucoma surgery or combined glaucoma and cataract surgery and alone cataract surgery. Meanwhile glaucoma patients' individual clinical characteristics and structural changes caused by anti-glaucoma surgery have shown differences in the impact on the predictive accuracy of IOL diopters and the type of refractive drift. This article reviews the latest research advances in the causes of refractive error(RE), the characteristics of refractive drift, and the selection of the most appropriate IOL formula for glaucoma patients undergoing cataract surgery or cataract surgery after anti-glaucoma surgery or combined glaucoma and cataract surgery.

14.
Chinese Journal of Medical Instrumentation ; (6): 54-60, 2023.
Article in Chinese | WPRIM | ID: wpr-971303

ABSTRACT

In this study, a surface electromyography (sEMG) and blood oxygen signal real-time monitoring system is designed to explore the changes of physiological signals during muscle fatigue, so as to detect muscle fatigue. The analysis method of sEMG and the principle of blood oxygen detection are respectively introduced, and the system scheme is expounded. The hardware part of the system takes STM32 as the core. Conditioning module composition; blood oxygen signal acquisition is based on near infrared spectroscopy (NIRS), specifically including light source, light source driving, photoelectric conversion, signal conditioning and other modules. The system software part is based on the real-time uC/OS-III software system. The characteristic parameters of sEMG were extracted by isometric contraction local muscle fatigue experiment; the relative changes of oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb) were calculated in the forearm blocking experiment, thereby verifying that the system collects two signals effectiveness.


Subject(s)
Muscle, Skeletal , Oxygen , Electromyography , Muscle Fatigue/physiology , Computers
15.
Chinese Journal of Natural Medicines (English Ed.) ; (6): 298-307, 2023.
Article in English | WPRIM | ID: wpr-982701

ABSTRACT

Five new terpenoids, including two vibsane-type diterpenoids (1, 2) and three iridoid allosides (3-5), together with eight known ones, were isolated from the leaves and twigs of Viburnum odoratissimum var.sessiliflorum. Their planar structures and relative configurations were determined by spectroscopic methods, especially 2D NMR techniques. The sugar moieties of the iridoids were confirmed as β-D-allose by GC analysis after acid hydrolysis and acetylation. The absolute configurations of neovibsanin Q (1) and dehydrovibsanol B (2) were determined by quantum chemical calculation of their theoretical electronic circular dichroism (ECD) spectra and Rh2(OCOCF3)4-induced ECD analysis. The anti-inflammatory activities of compounds 1, 3, 4, and 5 were evaluated using an LPS-induced RAW264.7 cell model. Compounds 3suppressed the release of NO in a dose-dependent manner, with an IC50 value of 55.64 μmol·L-1. The cytotoxicities of compounds 1-5 on HCT-116 cells were assessed and the results showed that compounds 2 and 3 exhibited moderate inhibitory activities with IC50 values of 13.8 and 12.3 μmol·L-1, respectively.


Subject(s)
Terpenes/pharmacology , Viburnum/chemistry , Molecular Structure , Diterpenes/chemistry , Plant Leaves/chemistry
16.
Chinese Journal of Medical Instrumentation ; (6): 512-517, 2023.
Article in Chinese | WPRIM | ID: wpr-1010230

ABSTRACT

In order to effectively treat respiratory diseases, a non-invasive positive pressure ventilator system is designed, the overall structure design of the system is proposed, and the hardware construction is completed. The breathing state of the patient is identified by the threshold triggering method of the flow rate of change, and the calculation of the flow rate of change is realized by the least squares method. At the same time, the breathing parameters are calculated in real time according to the flow-time and pressure-time characteristic curves. In addition, CMV, CPAP, BiPAP and PSV ventilation modes are also implemented. Finally, the parameter measurement accuracy and ventilation mode setting tests are carried out. The results show that the calculation of key breathing parameters provided by the system meets the relevant standards, and supports the stable output of 4 ventilation modes at the same time, provides breathing treatment for patients, and meets the basic functional requirements of the ventilator.


Subject(s)
Humans , Ventilators, Mechanical , Respiration
17.
São Paulo; s.n; s.n; 2023. 135 p. tab, graf.
Thesis in English | LILACS | ID: biblio-1437852

ABSTRACT

Proteins equipped with flavin adenine dinucleotides (FAD) or flavin mononucleotides (FMN) are named flavoproteins and constitute about 1% of all existing proteins. They catalyze redox, acid-base and photochemical reactions in a variety of biochemical phenomena that goes from energy metabolism to DNA repair and light sensing. The versatility observed in flavoproteins is ultimately a balance of flavin intrinsic properties modulated by a protein environment. This thesis aims to investigate how flavoproteins work by systematic evaluating flavin properties and reactivity. In particular, the mechanism of fumarate reduction by the flavoenzyme fumarate reductase Fcc3 was determined. Electronic-structure calculations were used for this task based on rigorous calibration with experimental data and error assessment. Flavin properties at chemical accuracy were obtained with single reference coupled-cluster CCSD(T) calculations at the complete basis set limit. Density functional theory was demonstrated an excellent alternative with lower computational costs and slightly less accuracy. Flavin protonation and tautomerism were shown to be important modulators of flavin properties and reactivity, with the possibility of various tautomers existing at neutral pH. Regarding flavin redox properties, an analysis based on multiconfigurational wave function weights was proposed for categorizing flavin redox reactions as hydride or hydrogen-atom transfers. This analysis is an upgrade over traditional partial charges methods and can be applied not only to flavin reactions but to any protoncoupled electron transfer. In the investigation of the enzymatic mechanism of fumarate reduction, the reaction was determined as a nucleophilic addition by hydride transfer with carbanion formation. Fumarate reductase employs electrostatic catalysis in contrast to previous proposals of substrate straining and general-acid catalysis. Also, hydride transfer was shown to be vibronically adiabatic with low tunneling contribution. These findings give new insights into the mechanisms of fumarate reductases and provide a framework for future computational studies of flavoproteins in general. The analyses and benchmark studies presented can be used to build better models of properties and reactivity of flavins and flavoproteins


Proteínas equipadas com dinucleotídeos de flavina-adenina (FAD) e mononucleotídeos de flavina (FMN) são chamadas flavoproteínas e constituem cerca de 1% de todas as proteínas existentes. Elas catalisam reações redox, ácido-base e fotoquímicas numa variedade de fenômenos bioquímicos que vão desde o metabolismo energético até reparo de DNA e captação de luz. A versatilidade observada em flavoproteínas é em última instância um balanço das propriedades intrínsecas de flavinas moduladas por um ambiente proteico. Esta tese busca investigar como flavoproteínas funcionam através de avaliações sistemáticas de propriedades e reatividade de flavinas. Em particular, o mecanismo de redução de fumarato pela flavoenzima fumarato redutase Fcc3 foi determinado. Cálculos de estrutura eletrônica foram usados para esta tarefa com base em rigorosa calibração com dados experimentais e avaliação de erros. As propriedades de flavinas foram determinadas com acurácia química com cálculos monoconfiguracionais de coupled-cluster CCSD(T) no limite de conjunto base completo. A teoria do funcional da densidade mostrou-se uma alternativa excelente com menor custo computacional e um pouco menos de acurácia. Protonação e tautomerismo de flavinas mostraram-se moduladores importantes de suas propriedades e reatividade, com a possibilidade de vários tautômeros existirem em pH neutro. Em relação às propriedades redox de flavinas, uma análise baseada nos pesos de funções de onda multiconfiguracionais foi proposta para categorizar as reações redox de flavinas como transferências de hidreto ou hidrogênio. Esta análise é uma melhoria em relação aos métodos tradicionais de cargas parciais e pode ser aplicada não apenas para reações de flavinas mas para qualquer transferência de próton acoplada a elétrons. Na investigação do mecanismo enzimático de redução de fumarato, a reação foi designada como uma adição nucleofílica por transferência de hidreto e formação de carbânion. A fumarato redutase usa catálise eletrostática diferentemente de prospostas anteriores envolvendo distorção do substrato e catálise ácida geral. Além disso, a transferência de hidreto mostrou-se vibronicamente adiabática com pouca contribuição de tunelamento. Estas descobertas abrem novas perspectivas sobre os mecanismos de fumarato redutases e fornecem uma base para estudos computacionais futuros sobre flavoproteínas em geral. As análises e estudos comparativos apresentados podem ser usados para construir melhores modelos para propriedades e reatividade de flavinas e flavoproteínas


Subject(s)
Comparative Study , Flavins/analysis , Flavoproteins/analysis , Calculi/chemistry , Static Electricity/adverse effects , Fumarates
18.
Indian J Ophthalmol ; 2022 Dec; 70(12): 4295-4299
Article | IMSEAR | ID: sea-224737

ABSTRACT

Purpose: This study was conducted to evaluate the accuracy of intraoperative aberrometry (IA) in intraocular lens (IOL) power calculation and compare it with conventional IOL formulas. Methods: This was a prospective case series. Eyes with visually significant cataract and axial hyperopia (AL <22.0 mm) underwent IA?assisted phacoemulsification with posterior chamber IOL (Alcon AcrySof IQ). Postoperative spherical equivalent (SE) was compared with predicted SE to calculate the outcomes with different formulas (SRK/T, Hoffer Q, Haigis, Holladay 2, Barrett Universal ? and Hill?RBF). Accuracy of intraoperative aberrometer was compared with other formulas in terms of mean absolute prediction error (MAE), percentage of patients within 0.5 D and 1 D of their target, and percentage of patients going into hyperopic shift. Results: Sixty?five eyes (57 patients) were included. In terms of MAE, both Hoffer Q (MAE = 0.30) and IA (MAE = 0.32) were significantly better than Haigis, SRK/T, and Barrett Universal ? (P < 0.05). Outcomes within ±0.5 D of the target were maximum with Hoffer Q (80%), superior to IA (Hoffer Q > IA > Holladay 2 > Hill?RBF > Haigis > SRK/T > Barrett Universal ?). Hoffer Q resulted in minimum hyperopic shift (30.76%) followed by Hill?RBF (38.46%), Holladay 2 (38.46%), Haigis (43.07%), and then IA (46.15%), SRK/T (50.76%) and Barrett Universal ? (53.84%). Conclusion: IA was more effective (statistically significant) in predicting IOL power than Haigis, SRK/T, and Barrett Universal ? although it was equivalent to Hoffer Q. Hoffer Q was superior to all formulas in terms of percentage of patients within 0.5 D of their target refractions and percentage of patients going into hyperopic shift

19.
Indian J Ophthalmol ; 2022 Sep; 70(9): 3431
Article | IMSEAR | ID: sea-224595

ABSTRACT

Background: Recently, the number of litigations on cataract surgeons has increased. Because of the increasing ambitions of surgeons and demands for a spectacle?free life, the incidence of unhappy patients is at an all?time high. To an ophthalmologist, the fruits of a good surgery are dependent largely on their skills. However, more importantly, the roots of good results of a surgery are laid by a perfect IOL (intraocular lens) power calculation. Inaccurate biometry is one of the major reasons for unhappy patients, especially in some challenging scenarios. Purpose: To hit the bull’s eye, as far as target refraction is concerned, it is necessary to understand the benefits and limitations of currently available cutting?edge technology and formulae and apply them to the cataract surgery practice. The aim of the video is to familiarize modern?day ophthalmologists to these situations to achieve a perfect IOL power calculation. Synopsis: Using a step?by?step approach, we decoded biometry in special scenarios like poor cornea, ocular surface disorders, dry eyes, toric IOL calculation, cases with posterior corneal astigmatism, irregular corneas like keratoconus, pellucid marginal degeneration, post Lasik ectasia and penetrating keratoplasty. In this video we tried to address the solution to these special conditions and how to attain target refraction in such cases. A few more issues are addressed like biometry post retina surgery, very dense cataract where it is difficult to obtain axial length, and cases with extreme axial lengths. Highlights: In this case?based approach, with relevant example, we tried to provide solutions for biometry in tricky scenarios like poor cornea, biometry post refractive surgery, dense cataracts, and cataract post retinal surgery. On following these commandments, not only will the litigations stop but our patients will be happier as well

20.
Rev. cuba. oftalmol ; 35(3)sept. 2022.
Article in Spanish | LILACS, CUMED | ID: biblio-1441741

ABSTRACT

Objetivo: Determinar los resultados refractivos con las fórmulas Holladay 2 y Barret Universal 2 a partir del cálculo de la lente intraocular en pacientes operados de catarata. Métodos: Se realizó un estudio descriptivo prospectivo y longitudinal con 60 ojos de 50 pacientes operados de catarata mediante la técnica de facoemulsificación. Se empleó para el cálculo de la lente el IOL Master 700 y el Pentacam AXL con la fórmula Holladay 2 y Barret Universal 2, respectivamente. Resultados: Predominó el sexo femenino y el grupo etario mayor de 60 años. Los ojos mayores de 26 mm mostraron la mayor diferencia entre el poder dióptrico de la lente intraocular que se implantó según Holladay y en menores de 22 mm según Barret Universal. Ambos grupos presentaron una disminución del equivalente esférico, siendo superior a 7 y 5 dioptrías en ojos mayores de 26 mm en el posoperatorio de ambas fórmulas. Posterior a la cirugía se observó una mejoría en la agudeza visual sin corrección y corregida de más de 4 líneas en la cartilla de Snellen, independiente de la longitud axial, para ambos grupos en estudio. Sin cambios significativos en el cilindro queratométrico. En el 70,0 por ciento de los casos, el resultado refractivo final estuvo en rango de la emetropía para el grupo Holladay 2 y el 66,7 por ciento para el grupo Barret Universal 2. Conclusiones: Ambas fórmulas resultan útiles para el cálculo de la lente intraocular en todos los rangos de longitud axial(AU)


Objective: To determine refractive outcomes with the Holladay 2 and Barret Universal 2 formulas from intraocular lens calculation in cataract surgery patients. Methods: A prospective and longitudinal descriptive study was performed with 60 eyes of 50 patients who underwent cataract surgery by phacoemulsification. The IOL Master 700 and Pentacam AXL with the Holladay 2 and Barret Universal 2 formula, respectively, were used to calculate the lens. Results: Female gender and age group older than 60 years predominated. Eyes larger than 26 mm showed the greatest difference between the dioptric power of the intraocular lens implanted according to Holladay and those smaller than 22 mm according to Barret Universal. Both groups presented a decrease of the spherical equivalent, being higher than 7 and 5 diopters in eyes larger than 26 mm postoperatively in both formulas. Postoperatively, there was an improvement in uncorrected and corrected visual acuity of more than 4 lines in the Snellen chart, independent of axial length, for both groups under study. No significant changes in keratometric cylinder. In 70.0 percent of the cases, the final refractive result was in the emmetropia range for the Holladay 2 group and 66.7 percent for the Barret Universal 2 group. Conclusions: Both formulas are useful for the calculation of the intraocular lens in all axial length ranges(AU)


Subject(s)
Humans , Female , Middle Aged , Cataract Extraction/adverse effects , Epidemiology, Descriptive , Prospective Studies , Longitudinal Studies
SELECTION OF CITATIONS
SEARCH DETAIL