The value of superior mesenteric artery preferential approach in the treatment of borderline resectable pancreatic head cancer / 中华普通外科杂志

Objective:To evaluate superior mesenteric artery preferential approach in the borderline resectable pancreatic head cancer.Methods:The clinical and follow-up data of 90 patients with borderline resectable pancreatic head cancer who underwent radical pancreatoduodenectomy at Beijing Chaoyang Hospital,Capital Medical University from Jan 2015 to Dec 2021 were analyzed.Results:After exploring the superior mesenteric artery in the lower colon area to confirm the vascular invasion meet the resection criteria, the blood supply is cut off first, then the tumors were resected en bloc, with the invaded vessels resected and reconstructed or replaced. All 90 patients successfully completed the operation without perioperative death. Pathology established pancreatic ductal adenocarcinoma. The 1-year, 2-year, and 3-year disease-free survival rates of patients in the arterial priority approach group were 68.2%, 60.4%, and 54.3%, while the 1-year, 2-year, and 3-year disease-free survival rates of patients by conventional approach were 58.4%, 26.4%, and 11.7% ( P=0.001). Conclusion:The superior mesenteric artery preferential approach in the inferior colon region can prolong the survival time of patients after surgery, and reduce the recurrence.

Clinical experience of off-pump arch branches preferential reconstruction and whole brain perfusion in the treatment of type A / 中华胸心血管外科杂志

Objective:To introduce the early results of total aortic arch replacement (TAA) without cardiopulmonary bypass (CPB) and without interruption of cerebral blood supply, using the technique of arch branches preferential reconstruction and whole brain perfusion for brain protection.Methods:Between June 2020 and March 2021, a total of 9 Stanford type A aortic dissection patients we performed total arch replacement by using the technique of arch branches preferential reconstruction and whole brain perfusion without cardiopulmonary bypass and without interruption of blood supply to the brain. The method of this reconstruction technique is as follows: A 24F aortic cannula was inserted into the true lumen at the root of the transverse innominate artery (IA) to connect one end of the artery for cardiopulmonary bypass. The access was connected to 14F artery via Y-connector and inserted into IA cavity to maintain blood supply to brain. Without cardiopulmonary bypass, the 10 mm branch of the four branch artificial blood vessel was anastomosed with the innominate artery IA. The perfusion collateral was connected to the second end of the artery of CPB (single pump and double tubes) to continue to supply blood for IA. The left common carotid artery (LCA) and left subclavian artery (LSCA) were reconstructed by the same method. When IA and LCA were anastomosed, the distal blood supply was not interrupted. After the three branches of the aortic arch were anastomosed, we started to turn the machine, then cooled down and blocked the ascending aorta to further complete the operation of the aortic root and arch. During the period of lower body circulatory arrest, the whole brain was perfused with low flow.Results:No intraoperative death or perioperative complications occurred in all patients, and they were discharged smoothly. The cardiopulmonary bypass time was (192.4±58.1) min, the aortic clamping time was (128.3±52.4) min, the lower body circulatory arrest time was (29.1±1.3) min, and the postoperative awake time was (8.2±3.7) h.Conclusion:Off-pump arch branches preferential reconstruction can provide physiological whole brain perfusion, shorten the cardiopulmonary bypass time and aortic occlusion time, and the operation is safe and effective.

Thermodynamic analysis and preferential solvation of gatifloxacin in DMF + methanol cosolvent mixtures / Análisis termodinâmico y solvatación preferencial de gatifloxacina en mezclas cosolventes DMF + metanol

SUMMARY This paper presents the thermodynamic analysis of solubility of gatifloxacin in the N,N-Dimethylformamide (DMF) + methanol (MeOH) cosolvent system at 10 temperatures. From the solubility data, the thermodynamic functions of solution, mixing, and transfers are calculated and analyzed using the Perlovich graphical method. On the other hand, an enthalpy-entropy compensation analysis is performed and the preferential solvation parameters are calculated using the inverse Kirkwood-Buff integral (IKBI) method. The result of the performed calculations indicates that the gatifloxacin solution process is endothermic with entropic favor, where the addition of DMF has a positive cosolvent effect in all cases. Regarding preferential solvation, the results are not entirely conclusive, since in all cases the values of the preferential solvation parameter are less than 0.01, so that, negligible preferential solvation takes place.

RESUMEN Este artículo presenta el análisis termodinâmico de la solubilidad de gatifloxacina en el sistema cosolvente de A,A-Dimetilformamida (DMF) + metanol (MeOH) a 10 temperaturas. A partir de los datos de solubilidad se calculan las funciones termodinámicas de solución, mezcla y transferencia. Para el análisis además se utiliza el método gráfico Perlovich. Por otro lado, se realiza un análisis de compensación entalpía-entropía y se calculan los parámetros de solvatación preferencial utilizando el método de las integrales inversas de Kirkwood-BufF (IIKB). Los resultados del análisis termodinámico indican que el proceso de solución de gatifloxacina es endotérmica con favorecimiento entrópico, donde la adición de DMF tiene un efecto cosolvente positivo en todos los casos. En cuanto a la solvatación preferencial, los resultados no son del todo concluyentes, debido a que en todos los casos los valores del parámetro de solvatación preferencial son menores a 0,01 indicando una solvatación insignificante.

Preferential mode of zinc and adherence to treatment: zinc syrup or zinc tablet

Background: Diarrhoea has evident itself among the leading causes of under-five childhood mortality globally as well as in India. Although the benefits of zinc supplementation in diarrhoea management have been established, there remain many barriers to the widespread implementation of this treatment strategy. In India, a very small proportion of children in need, 20 per cent in urban and merely 5 per cent in rural, have access to zinc supplementation. The study aimed to assess zinc adherence in the community and find out the preferential mode of zinc as tablet or syrup, to stick to the scheduled adherence.Methods: The proposed method of study is a simple household survey complimented by secondary research around the preference and usage of zinc and ORS among under five children, suffered from diarrhoea in the last 14 days preceding the survey date.Results: The study revealed that 95 per cent of the respondents preferred zinc syrup over zinc tablet for treatment of diarrhoea due to its ease to administer and palatable taste to children. Eighty nine per cent of the total urban and 62 per cent of total rural respondents received zinc in syrup form, indicating the preferred mode of zinc by service providers over tablets.Conclusions: It has been observed that the caregivers tend to give the complete dosage of zinc if it is available in the syrup form. However, it is important to generate evidence to understand the preferential mode of zinc; tablet or syrup in terms of administration of drug, its usage and its cost.

Combing and Discussion of Research Suggestions About Classical Traditional Chinese Medicine Excellent Prescriptions / 中国实验方剂学杂志

Classical traditional Chinese medicine(TCM) excellent prescriptions is an outstanding representative in prescriptions of traditional Chinese medicine,clinical medicine effective tool,and the essence of traditional culture of Chinese medicine.The research and development of classical TCM excellent prescriptions has attracted great attention from group in the whole industry chain of TCM,a series of guiding suggestions and targeted literature laid a good foundation for research and development of classical TCM excellent prescriptions.In this paper,based on the CNKI database,literature about suggestions or enlightenments of classical TCM excellent prescriptions was sorted and refined in order to build the research outline of classical TCM excellent prescriptions,and it was concluded that literature research was the premise,medicine/decoction pieces with good quality was the foundation,standard substance was the core,high quality was the guarantee and preferential policies were the impetus,and related discussions were carried out.All these were expected to promote the research of classical TCM excellent prescriptions and development of related industries.

Preferential solvation of tricin in {ethanol (1) + water (2)} mixtures at several temperatures / Solvatación preferencial de tricin en mezclas etanol + agua a varias temperaturas

SUMMARY The preferential solvation parameters of tricin in {ethanol (1) + water (2)} binary mixtures were obtained from their thermodynamic properties by means of the inverse Kirkwood-Buff integrals method. Tricin is very sensitive to specific solvation effects, so the preferential solvation parameter by ethanol (1), δx 1,3 is negative in the water-rich mixtures but positive in all the other compositions at temperatures from 293.15, to 313.15 K. It is conjecturable that in water-rich mixtures the hydrophobic hydration around the aromatic and methyl groups of the drug plays a relevant role in the solvation. The higher drug solvation by ethanol in mixtures of similar solvent proportions and in ethanol-rich mixtures could be due mainly to polarity effects. In these mixtures, the drug would be acting as Lewis acid with the ethanol molecules because this co-solvent is more basic than water.

RESUMEN Los parámetros de solvatación preferencial del tricina en mezclas {etanol (1) + agua (2)} se obtuvieron a partir de las propiedades termodinámicas de solución, mediante el método de las integrales inversas de Kirkwood-Buff. La tricina es muy sensible a los efectos de solvatación específicos, por lo que el parámetro de solvatación preferencial, δx 1,3 es negativo en las mezclas ricas en agua, pero positivo en todas las otras composiciones a temperaturas desde 293,15 hasta 313,15 K. Se puede establecer que en mezclas ricas en agua la hidratación hidrofóbica alrededor de los grupos aromáticos y metilo del fármaco tiene un papel relevante en la solvatación. La mayor solvatación del fármaco por etanol se presenta en mezclas de proporción intermedia y en mezclas ricas en etanol, esto podría deberse principalmente a los efectos de la polaridad. En estas mezclas, el fármaco actuaría como ácido de Lewis con las moléculas de etanol, puesto que este codisolvente es más básico que el agua.

Application of the arterial approach in laparoscopic pancreatoduodenectomy / 中华消化外科杂志

Pancreaticoduodenectomy is the main treatment method for pancreatic head carcinoma and periampullary cancer,and is also the only possible cure way.With the development of minimally invasive surgery,laparoscopic pancreaticoduodenectomy has been widely carried out,it even has been the routine operation in some pancreatic surgery center.The traditional approach is still the main approach for laparoscopic pancreaticoduodenectomy.In recent years,the procedure of the artery approach with its advantages has been put forward and gradually developed in laparoscopic pancreaticoduodenectomy through the continuous study and exploration.On the basis of the early arterial approach,authors' center established an artery preferential disconnection procedure in laparoscopic pancreaticoduodenectomy,which has been named arterial first approach.In the clinical practices and studies,this procedure also represents its unique advantages.

Discursos de la vulnerabilidad bajo el gerenciamiento educativo: Análisis Ley de subvención escolar preferencial chilena

En el presente artículo indagamos cómo las nociones de vulnerabilidad escolar y gerenciamiento educativo se han instalado discursivamente en el campo legislativo de la educación chilena. La incorporación de estos elementos ha implicado una transformación profunda en la escuela, en donde la lógica de la rendición de cuentas convive con el ideario de la igualdad de oportunidades. Sobre la base de la estrategia discursiva de los repertorios interpretativos (Pottery Wetherell, 1987), se analiza las funciones que el estudiante vulnerable o "prioritario" juega en el corpus textual de la Ley 22.248 de Subvención Escolar Preferencial. Los resultados muestran tres tipos de repertorios interpretativos: a) El de la igualdad de oportunidades, b) El técnico y c) El del management. Por último, se discute las implicancias del concepto de vulnerabilidad, especialmente en lo respectivo a las distintas lógicas presentes para abordarlo, en un contexto de mercantilización y de políticas de gerenciamiento en educación.

The present study investigates, through discourse analysis, how the notions of school vulnerability and educational management have been established in the Chilean education legislation. The incorporation of these elements has implied a profound transformation on schools, where the accountability logic coexists with an equality of opportunities value. Based on the interpretative repertoires approach (Potter y Wetherell, 1987), we analyzed the functions that a vulnerable or "critical” student plays in the text corpus of the 20.248 Preferential School Subsidy law. This analysis yielded three kinds of interpretative repertories: a) Equally of Opportunities, b) Technical, and c) Management. Results are discussed in terms of the implications of the vulnerability concept, especially regarding the different logics available in a context of commercialization and education management policies.

Neste artigo, investigamos como as noções de vulnerabilidade escolar e gerenciamento educacional foram instaladas de forma discursiva no campo legislativo da educação chilena. A incorporação desses elementos envolveu uma profunda transformação na escola, onde a lógica da responsabilidade coexiste com a idéia de igualdade de oportunidades. Com base na estratégia discursiva dos repertórios interpretativos (Potter e Wetherell, 1987), são analisadas as funções que o aluno vulnerável ou "priorizado" desempenha no corpus textual da Lei 22.248 da Lei Preferencial de Bolsas Escolares. Os resultados mostram três tipos de repertórios interpretativos: a) O de igualdade de oportunidades, b) O técnico e c) O da gestão. Finalmente, são discutidas as implicações do conceito de vulnerabilidade, especialmente no que diz respeito às diferentes lógicas presentes para abordálo, em um contexto de comercialização e políticas de gestão na educação.

Solution thermodynamics and preferential solvation of 3-chloro-N-phenyl-phthalimide in acetone + methanol mixtures / Termodinámica de soluciones y solvatación preferencial de 3-cloro-N-fenil-ftalimida en mezclas acetona + metanol

The thermodynamic properties of the 3-chloro-N-phenyl-phthalimide in acetone + methanol cosolvent mixtures were obtained from solubility data report in literature. The solubility was higher in near acetone and lower in pure methanol at all temperatures studied. A non-linear plot of ∆solnH° vs. ∆solnG° shows a negative slope from pure acetone up to x1 = 0.691. Beyond this composition, a variable positive slope is obtained with the exception of mixtures with x1 = 0.121, x1 = 0.272 and x1 = 0.356 which is a not common trend in these systems. The preferential solvation of 3-chloro-N-phenyl-phthalimide by the components of the solvents was estimated by means of the inverse Kirkwood-Buff integral method, showing the 3-chloro-Nphenyl-phthalimide is preferential solvated by methanol in more polar mixtures and by acetone in less polar ones.

Las propiedades termodinámicas de 3-cloro-N-fenil-ftalimida en mezclas cosolventes acetona + metanol fueron obtenidas a partir de los datos de solubilidad reportados en la literatura. La mayor solubilidad se presentó en acetona y la menor en metanol puro en todas las temperaturas estudiadas. La grafica ΔsolnH° vs. ΔsolnG° presenta una tendencia no lineal, con una pendiente negativa desde la acetona pura hasta x1 = 0,691 a partir de esta composición hasta el metanol puro se obtiene una pendiente positiva variable con la excepción de las mezclas con x1 = 0,121, x1 = 0,272 y x1 = 0,356, la cual es una tendencia poco común en estos sistemas. La solvatación preferencial de 3-cloro-N-fenil-ftalimida por cada uno de los solventes de la mezcla se estimó por medio del método de las integrales inversas de Kirkwood-Buff mostrando que la 3-cloro-N-fenil-ftalimida se solvata preferencialmente por metanol en las mezclas más polares y por acetona en las menos polares.

Study on the correlation factors of residents in preferentially using essential medicines based on Andersen behavior model / 中华医院管理杂志

Objective To analyze the correlation factors that promote or impede the residents to preferentially use essential medicines.Methods Adopting stratified random sampling method,1 700 households selected from 5 cities of Shandong province were investigated with a questionnaire.The framework of Andersen behavior model of health service utilization was used as the framework,with such methods as descriptive analysis and univariate logistic regression models for the analysis and evaluation of relevant information.Results The residents′ tendency factor,ability factor and environmental factor influence their preference to use essential medicines,while the requirement factor plays a minimal role.There was a significant difference for the preference of combined medication,first visit preference and self-medication experience,the efficacy and policy response of essential medicine from logistic regression analysis.Conclusion At present,the government should focus on the construction of the formation mechanism of the residents′drug use behavior and the policy response mechanism of essential medicine system.

Application of nasal continuous positive airway pressure preferential ventilation strategy in the treatment of infant severe pneumonia / 中国医师进修杂志

Objective To investigate the value of nasal continuous positive airway pressure (NCPAP) in the treatment of severe pneumonia. Methods The clinical data of 59 severe pneumonia infants who received NCPAP preferential ventilation strategy were retrospectively analyzed. Results After treatment, 50 infants were effective and 9 infants were ineffective. Before treatment, the age, RR, HR between effective group and ineffective group had no significant differences (P>0.05). But the levels of PaCO2, PaO2/FiO2 in ineffective group were significantly higher than those in effective group and the level of PaO2 in ineffective group was significantly lower than that in effective group (P<0.05). In effective group, the levels of PaO2 and PaO2/FiO2 were significantly increased after treatment for 1, 12 and 24 h, and the levels of PaCO2, RR and HR were significantly decreased (P<0.01). Conclusions NCPAP preferential ventilation strategy can reduce the use of invasive mechanical ventilation, improve oxygenation, ease dyspnea and make vital signs stable.

Solvatación preferencial de la naringina en mezclas cosolventes etanol + agua mediante el método de las integrales inversas de Kirkwood-Buff / Preferential solvation of naringin in ethanol + water cosolvent mixtures according with the inverse Kirkwood-Buff integrals

Los parámetros de solvatación preferencial, es decir, las diferencias entre la fracción molar local y de la solución de los solventes en solución de naringina se derivan de su solubilidad en mezclas cosolventes mediante el método de las integrales inversas de Kirkwood-Buff. Según el método IKBI, la naringina es sensible a los efectos específicos de solvatación según la composición cosolvente, por lo que el parámetro de solvatación preferencial por δx1,3, es negativo en mezclas ricas en agua y en mezclas ricas en etanol, pero positivo en composiciones entre 0,24 y 0,40 en fracción molar de etanol. Esto podría demostrar el papel relevante de hidratación hidrofóbica alrededor de los grupos no polares en la solvatación de fármacos en mezclas ricas en agua. Por otro lado, en mezclas de composiciones cosolventes intermedias, el fármaco es solvatado principalmente por etanol, posiblemente debido al comportamiento básico de la mezcla cosolvente; mientras que en mezclas ricas en etanol, la solvatación preferencial por el agua podría deberse al carácter ácido del agua.

The preferential solvation parameters, i.e., the differences between the local and bulk mole fractions of the solvents in solutions of naringin is derived from their solubility in binary solvent mixtures by means of the inverse Kirkwood-Buff integral (IKBI) method. According to IKBI method it is found that naringin is sensitive to solvation effects, so the preferential solvation parameter by ethanol δx1,3, is negative in waterrich and ethanol-rich mixtures but positive in compositions from 0.24 to 0.40 in mole fraction of ethanol. This could demonstrate the relevant role of hydrophobic hydration around the non-polar groups in the drug solvation in water-rich mixtures. Otherwise, in mixtures of intermediate co-solvent compositions, the drug is mainly solvated by ethanol, probably due to the basic behavior of the co-solvents; whereas, in ethanol-rich mixtures, the preferential solvation by water could be due to the acidic behavior of water.

Some numerical analyses on the solubility of vanillin in Carbitol® + water solvent mixtures / Algunos análisis numéricos sobre la solubilidad de la vainillina en mezclas cosolventes Carbitol® + agua / Alguns análises numéricas da solubilidade de vanilina em misturas de solventes carbitol® + água

In this communication some reported solubility values of vanillin (component 3) in 2-(2-ethoxyethoxy)ethanol (Carbitol®, component 1) + water (component 2) mixtures at five temperatures from 298.15 to 318.15 K were correlated with the Jouyban-Acree model combined with van't Hoff or Apelblat equations, obtaining models in second degree regarding the mixtures compositions. Mean percentage deviations were near to 6.0%. On the other hand, by means of the inverse Kirkwood-Buff integrals it was demonstrated that vanillin is preferentially solvated by water in water-rich mixtures (with a minimum δx1,3 value in the mixture x1 = 0.05, i.e. -4.29 x 10-2) but preferentially solvated by the cosolvent in mixtures with compositions 0.12 < x1 < 1.00 (with a maximum δx1,3 value equal to 3.61 x 10-2 in the mixture x1 = 0.25). It is conjectural that hydrophobic hydration plays a relevant role in the first case, whereas, in the second case, vanillin would be acting as Lewis acid with Carbitol®.

Nesta pesquisa alguns valores de solubilidade da vanilina (componente 3) em misturas 2-(2-etoxietoxi)etanol (Carbitol®, componente 1) + água (componente 2) em várias temperaturas (298,15-318,15 K) foram correlacionados com o modelo Jouyban-Acree combinado com as equações do van't Hoff ou Apelblat obtendo modelos de ordem dois. Os desvios médios percentuais foram cercanos a 6,0%. Por outro lado, por meio das integrais inversas do Kirkwood-Buff demonstrou-se que a vanilina é preferencialmente solvatada pela água em misturas ricas em agua (com um valor mínimo de δx1,3 igual a -4,29 x 10-2 obtido na mistura de composição x1 = 0,05), mas, preferencialmente, solvatada pelo cosolvente, em misturas com composições 0,12 < x1 < 1,00 (com um valor máximo de δx1,3 igual a 3,61 x 10-2 obtido na mistura de composição x1 = 0,25). É conjecturável que a hidratação hidrofóbica desempenha um papel relevante no primeiro caso, enquanto que, no segundo caso a vanilina está atuando como ácido de Lewis com moléculas do Carbitol®.

En esta comunicación se presenta la correlación de algunos valores de solubilidad de vainillina (componente 3) en mezclas 2-(2-etoxietoxi)etanol (Carbitol®, componente 1) + agua (componente 2) reportados previamente en la literatura a cinco temperaturas desde 298,15 hasta 313,15 K mediante el modelo de Jouyban-Acree combinado con las ecuaciones de van't Hoff y de Apelblat. En el análisis se obtuvieron modelos de segundo orden respecto a la composición de las mezclas disolventes. Las desviaciones porcentuales promedio fueron cercanas al 6,0%. Por otro lado, mediante las integrales inversas de Kirkwood-Buff se demostró que la vainillina es solvatada preferencialmente por el agua en mezclas ricas en agua (con un valor mínimo de δx1,3 igual a -4,29 x 10-2 obtenido en la mezcla de composición x1 = 0,05) pero preferencialmente solvatada por el cosolvente en mezclas con composiciones 0,12 < x1 < 1,00 (con un valor máximo de δx1,3 igual a 3,61 x 10-2 obtenido en la mezcla de composición x1 = 0,25). Se podría conjeturar que la hidratación hidrofóbica juega un papel relevante en el primer caso, mientras que en el segundo caso, la vainillina estaría actuando como ácido de Lewis frente a las moléculas de Carbitol®.

Association between hyperacuity defects and retinal microstructure in polypoidal choroidal vasculopathy.

Purpose: To improve our understanding of hyperacuity defects measured with preferential hyperacuity perimetry (PHP) by correlating PHP findings with the retinal microstructural changes visible on spectral‑domain optical coherence tomography (OCT) in patients with polypoidal choroidal vasculopathy (PCV). Materials and Methods: Twenty‑eight eyes of 28 patients with PCV were retrospectively reviewed. All patients underwent a complete ophthalmologic examination, including best‑corrected visual acuity (logMAR) testing, PHP, and OCT. The functional ‘PHP test score’ and ‘total volume of hyperacuity defect zone’ were also analyzed. Results: Patients were classified based on the hyperacuity defect by PHP, as follows: Hyperacuity defect (n = 17 eyes) group and hyperacuity intact (n = 11 eyes) group. The mean best‑corrected visual acuity in the hyperacuity intact group (0.46 ± 0.39) was better than that in the hyperacuity defect group (0.82 ± 0.37) (P = 0.014). The presence of serous retinal detachment and retinal pigment epithelial detachment did not differ significantly between groups (P = 0.120 and P = 0.689, respectively). A disrupted photoreceptor layer was more common in the hyperacuity defect group compared with the hyperacuity intact group (P = 0.0001). Among 17 eyes with a hyperacuity defect, 9 eyes showing intra‑retinal pathology (intra‑retinal cyst or hard exudates) and had a significantly higher PHP test score and larger total volume of the hyperacuity defect zone than 8 eyes without intra‑retinal pathology (P = 0.006 and P = 0.021, respectively). Conclusion: A hyperacuity defect in PCV was associated with photoreceptor disarrangement. Furthermore, PCV lesions on the inner retina that invaded the photoreceptor layer were associated with a more severe hyperacuity defect.

Preferential solvation of acetaminophen in ethanol + water solvent mixtures according to the inverse Kirkwood-Buff integrals method / Solvatación preferencial del acetaminofeno en mezclas cosolventes etanol + agua según el método de las integrales inversas de Kirkwood-Buff

The preferential solvation parameters, i.e., the differences between the local mole fraction of solvents around the solute and those for the bulk co-solvent mixtures in solutions of acetaminophen in ethanol + water binary mixtures were derived from their thermodynamic properties by means of the inverse Kirkwood-Buff integrals (IKBI) method. It is found that acetaminophen is sensitive to solvation effects, so the preferential solvation parameter δxE,A, is negative in water-rich and ethanol-rich mixtures but positive in co-solvent compositions from 0.24 to 0.73 in mole fraction of ethanol. It is conjecturable that in water-rich mixtures the hydrophobic hydration around the aromatic ring and methyl group present in the drug plays a relevant role in the solvation. The more solvation by ethanol in mixtures of similar co-solvent compositions could be due mainly to polarity effects. Finally, the preference of this drug for water in ethanol-rich mixtures could be explained in terms of the bigger acidic behavior of water molecules interacting with the hydrogen-acceptor groups present in acetaminophen such as the carbonyl group.

Con base en algunas propiedades termodinámicas clásicas de solución en este trabajo, se calcularon los parámetros de solvatación preferencial del acetaminofeno (δxE,A) en mezclas etanol + agua mediante las integrales inversas de Kirkwood-Buff. Los parámetros δxE,A corresponden a las diferencias entre las fracciones molares locales de los solventes alrededor del soluto y en el grueso de la solución. Con base en estos valores, se puede observar que este fármaco es altamente sensible a efectos específicos de solvatación que varían según la composición cosolvente. Así, los valores de δxE,A son negativos en mezclas ricas en agua y en mezclas ricas en etanol, pero positivos en composiciones desde 0,24 hasta 0,73 en fracción molar de etanol. Es probable que la hidratación hidrofóbica alrededor del anillo aromático y el grupo metilo del acetaminofeno pueda tener un papel relevante en la solvatación del fármaco en mezclas ricas de agua. En mezclas de composición intermedia, la mayor solvatación por las moléculas de etanol podría deberse principalmente a efectos de polaridad. Finalmente, la preferencia que este fármaco manifiesta por el agua en mezclas ricas en etanol podría explicarse en términos del mayor comportamiento ácido de las moléculas del agua, que estarían interactuando con los grupos aceptores de hidrógeno presentes en el acetaminofeno, tales como el carbonilo.

Preferential solvation of xylitol in ethanol + water co-solvent mixtures according to the IKBI and QLQC methods / Solvatación preferencial del xilitol en mezclas cosolventes etanol + agua según los métodos IKBI y QLQC / Solvatação preferencial do xilitol no misturas cosolventes etanol + água acordo o métodos IKBI e QLQC

The preferential solvation parameters, i.e., the differences between the local around the solute and bulk mole fractions of the solvents in solutions of xylitol in ethanol + water binary mixtures are derived from their thermodynamic properties by means of the inverse Kirkwood-Buff integrals (IKBI) and quasi-lattice quasi-chemical (QLQC) methods. According to IKBI method it is found that xylitol is sensitive to solvation effects, so the preferential solvation parameter δxE,S, is slightly positive in water-rich and negative in mixtures beyond 0.25 in mole fraction of ethanol. In different way, according to QLQC method, negative values of δxE,S are found in all the compositions evaluated. The more solvation by ethanol observed in water-rich mixtures could be due mainly to polarity effects. Otherwise, the preference of this compound for water in ethanol-rich mixtures could be explained in terms of the bigger acidic behavior of water interacting with hydrogen-acceptor hydroxyl groups in xylitol.

Partiendo de algunas propiedades termodinámicas clásicas se calcularon los parámetros de solvatación preferencial del xilitol (dxE,S) en mezclas etanol + agua mediante el método de las integrales inversas de Kirkwood-Buff (IKBI) y el método cuasi-enrejado-cuasi-químico (QLQC). Los parámetros dxE,S corresponden a las diferencias entre las fracciones molares locales alrededor del soluto y en el grueso de la solución. Con base en estos valores, se encuentra que este compuesto es altamente sensible a los efectos específicos de solvatación según la composición cosolvente. Así, según el método IKBI, los valores de dxE,S son positivos en mezclas ricas en agua pero negativos en composiciones desde 0.25 en fracción molar de etanol hasta el etanol puro. Sin embargo, según el método QLQC, los valores de dxE,S son negativos en todas las composiciones co-solventes analizadas. En mezclas ricas en agua la mayor solvatación por las moléculas de etanol podría deberse principalmente a efectos de polaridad. De otro lado, la preferencia que manifiesta este compuesto por el agua en mezclas ricas en etanol podría explicarse en términos del mayor comportamiento ácido del agua que estaría interactuando con los grupos aceptores de hidrógeno presentes en el soluto.

Começando a partir de algumas propriedades termodinâmicas clássicos neste trabalho, foram calculados os parâmetros de solvatação preferenciais de xilitol (δxE,S) em misturas etanol + água pelo método de integrais inversas de Kirkwood-Buff (IKBI) e o método quase-reticulado quase-químicas (QLQC). Parâmetros δxE,S correspondem às diferenças entre as fracções molares locais ao redor do soluto na solução e a granel. Com base nestes valores se verifique que este composto é extremamente sensível aos efeitos específicos de solvatação por composição de cosolvente. Assim, de acordo com o método IKBI, valores δx E,S são positivas em misturas ricas em água, mas negativas em composições 0,25 de fracção mole de etanol a etanol puro. No entanto, de acordo com o método QLQC, os valores de δxE,S são negativas em todas as composições testadas. Solvatação de xilitol por moléculas de etanol em misturas ricas em água pode ser devido por polaridade. Por outro lado, a preferência de este composto por água em misturas em etanol pode ser explicada em termos de comportamento ácido de água com os grupos aceitadores de hidrogénio presentes no soluto.

Meiotic and mitotic behaviour of B chromosomes of ryegrass / Comportamento dos cromossomos B na mitose e na meiose de azevém

Mitotic and meiotic analyses using conventional and fluorescent stains were employed in plants (accession ETBAZ 055 - origin: Capão do Leão, Rio Grande do Sul State, Brazil) from the Germplasm Active Bank of Ryegrass (Banco Ativo de Germoplasma de Azevém) of Embrapa, for observing the behaviour of B chromosomes. In several meiotic stages, there were observed up to two B chromosomes, which have presented an unstable behaviour regarding their precocious ascension to metaphase I or delays during anaphase I. At the end of the process, the Bs showed predominantly segregation for the nuclei under formation in order to guarantee their propagation. Concerning the cells that comprise the anther tapetum and the root meristems, the B chromosomes have presented a more stable behaviour.

Análises mitóticas e meióticas com coloração convencional e fluorescente foram realizadas em plantas (acesso ETBAZ 055 - procedência Capão do Leão, Rio Grande do Sul) provenientes do Banco Ativo de Germoplasma de Azevém da Embrapa para observar o comportamento dos cromossomos B. Em vários estágios da meiose, foram observados um a dois cromossomos B, os quais apresentaram um comportamento instável, com ascensão precoce na metáfase I ou atrasos na anáfase I. Ao final do processo, os Bs exibiram predominantemente segregação para os núcleos em formação, a fim de garantir a sua propagação. Nas células que constituem o tapete da antera e nos meristemas da raiz, os cromossomos B apresentaram um comportamento mais estável.

An Analysis of Metamorphopsia Using Preferential Hyperacuity Perimeter Following Macular-off RRD Surgical Repair

PURPOSE: To determine the efficacy of using the preferential hyperacuity perimeter (PHP) for the analysis of metamorphopsia following macular-off rhegmatogenous retinal detachment (RRD) surgical repair. METHODS: PHP examination was performed in those who complained of metamorphopsia after successful surgical reattachment of RRD. The subjective symptoms were evaluated based on a scale, ranging from 0 to 10, and were compared with the results of PHP examination. Patients age, duration of retinal detachment, pre and post-operative visual acuity, postoperative presence of subretinal fluid (SRF), surgical methods, presence of epiretinal membrane, and time from operation to PHP test were analyzed to find the correlation with the PHP results. RESULTS: Of the 19 eyes included in this study, nine eyes were found to have a hyperacuity defect upon PHP examination. In this group, the subjective level of metamorphopsia was significantly worse (p<0.01), the age was significantly higher (p=0.02), and SRF persisted in the macula more frequently at two months postoperatively (p=0.04), as compared to those without the defect. There were no significant differences in the other factors. CONCLUSIONS: Subjectively severe metamorphopsia after surgery for RRD could be confirmed objectively using PHP. In the case of older patients and persistent submacular fluid, metamorphopsia would develop more frequently due to displacement of the photoreceptors in the process of reattachment.

Pruebas para la evaluación de la agudeza visual en pacientes pediátricos / Tests for the visual acuity assessment in pediatric patients

La medición de la agudeza visual en niños representa un importante reto para el optómetra por ser laboriosa y requerir conocimiento y paciencia. Según el estímulo, la agudeza visual puede dividirse en tres tipos: de detección, de resolución y de reconocimiento. Los valores de estas pueden ser diferentes y se alteran en diferente proporción en presencia de problemas visuales. El presente artículo hace una revisión de los tests de agudeza visual para niños, sobre los que se han realizado gran número de investigaciones en los últimos años: Teller, Cardiff, Lea, HOTV y las cartillas logMAR que podrían emplearse en el grupo de escolares.Conclusiones: las pruebas contempladas en esta revisión no son necesariamente las más utilizadoas en nuestra práctica clínica cotidiana; sin embargo, la actividad investigativa en torno a éstas ha aportado a la construcción de protocolos diagnósticos. El referente para una mejor práctica clínica debe ser la optometría basada en la evidencia, ya que ésta permite a los profesionales disponer de nuevos elementos de juicio objetivos, con fundamento científico, que contribuyan a la elección de la mejor alternativa para determinar la agudeza visual en los niños. El optómetra debe seguir rigurosamente los protocolos de evaluación de la agudeza visual para dar a sus mediciones mayor confiabilidad y analizar los resultados obtenidos dentro del contexto de la historia clínica. Los métodos para la evaluación de la agudeza visual pueden adaptarse de acuerdo con las habilidades, el conocimiento y la experiencia del niño que va a examinarse. Con esta revisión se evidencia la importancia de realizar estudios sobre la aplicación de estos tests en nuestro medio con el fin de evaluar su confiabilidad y utilidad en nuestros pacientes.

The visual acuity measurement in children is an important Challenger for the optometrist, given de complexity of the task and to require knowledge and patience. According to the stimulus, the visual acuity can be divided in three types: detection, resolution and recognition. The values of these can be different and they are altered in different proportion in the presence of visual problems. The present article makes an overhaul of the test of the visual acuity for children which years have generated great number of investigations in the past years: Teller, Cardiff, Lea, HOTV and logMAR charts that could be used in the school age group.Conclusions: The tests reviewed are not necessarily used commonly used our clinical daily practice, nevertheless the investigative activity concerning these has reached in the construction of diagnostic protocols. The reference for a better clinical practice must be the optometry based on the evidence, since this one allows to the professionals to have new facts that contribute to the election of the best alternative to determine the visual acuity in the children. The optometrist a must follow rigorously the protocols of evaluation of the visual acuity to give to measurements major reliability and to analyze the results obtained inside the context of the history. The methods for the evaluation of the visual acuity can be adapted in agreement with the skills, knowledge and experience of the child being examinated. There is evident the importance of realizing studies on the application of these test in order to evaluate their reliability and utility in our patients

Preferential Hyperacuity Perimeter in Exudative AMD With Pigment Epithelial Detachment

PURPOSE: To analyze the hyperacuity defects by preferential hyperacuity perimeter (PHP) in exudative age-related macular degeneration (AMD) and correlate them with the properties of pigment epithelial detachment (PED) obtained by optical coherence tomography (OCT). METHODS: Thirty eyes with exudative AMD with choroidal neovascularization (CNV) diagnosed by fluorescein angiography underwent PHP for hyperacuity defect and OCT for PED length and height. We compared hyperacuity defect with the shape of the PED by OCT. RESULTS: 26 eyes with exudative AMD with CNV tested positive for hyperacuity defects. The size of the hyperacuity defect by PHP and the PED length by OCT showed positive correlation (p=0.010). In the 4 eyes that tested negative for hyperacuity defects, the PED was not high although the size was large. CONCLUSIONS: Our results suggest that PHP is a useful method to detect a change of pigment epithelial layer in AMD and the presences of a hyperacuity defect is more sensitive for PED height than size. These results suggest that PHP is useful to detect the state and the activity of CNV lesion.