A selective and new spectrophotometric method is described for determination of five 1,4 dihydropyridine drugs (1,4- DHP);namely nifedipine (NIF), nicardipine (NIC), nimodipine (NIM), felodipine (FEL) and amlodipine (...A selective and new spectrophotometric method is described for determination of five 1,4 dihydropyridine drugs (1,4- DHP);namely nifedipine (NIF), nicardipine (NIC), nimodipine (NIM), felodipine (FEL) and amlodipine (AML). The method is based on a coupling reaction between the cited drugs and vanillin reagent in acidic condition. Under optimized conditions, the red coloured products were measured at 500 nm for NIF, NIC, NIM and FEL or at 479 nm for AML. Molar absorptivities were ranged from 0.575 × 104 - 1.065 × 104 l·mol-1·cm-1, Beer’s law was obeyed at 5 - 70 μg/mL concentration range and the limit of detection was ranged from 0.150 - 1.500 μg/mL. The proposed method was successfully extended to pharmaceutical preparations tablets and capsules and comparison by Student’s t-test and variance ratio F-test showed no significant difference.展开更多
This paper is one of a series of reports of theoretical researches on the mechanism of the Mannich reaction using the iminium salt as the potential Mannich reagent. According to the results of AM1 dynamic calcula...This paper is one of a series of reports of theoretical researches on the mechanism of the Mannich reaction using the iminium salt as the potential Mannich reagent. According to the results of AM1 dynamic calculations, the activation energies of key steps in conventional Mannich reactions between ammonia, formaldehyde and acetaldehyde in neutral and acidic media are 438 8 kJ/mol and 393 9 kJ/mol respectively. The activation energy of the rate controlling step of the Mannich reaction which contains the potential Mannich reagent is 274 7 kJ/mol. Therefore, it can be derived that the potential Mannich reagent can increase the rate of the reaction remarkably. The reasons for this have been discussed in terms of the orbital match and electrostatic interaction between the atoms of reactant complexes. In this paper another different conjectured mechanism of the potential Mannich reagent which can reduce the activation energy is considerably studied.展开更多
Based on an extended London-Eyring-Polanyi-Sato （LEPS） potential energy surface （PES）, the Ba q-HF reaction has been studied by the quasi-classical trajectory （QCT） method. The reaction integral cross section as...Based on an extended London-Eyring-Polanyi-Sato （LEPS） potential energy surface （PES）, the Ba q-HF reaction has been studied by the quasi-classical trajectory （QCT） method. The reaction integral cross section as a function of collision energy for the Ba q- HF --＊ BaF q- H reaction is presented and the influence of isotope substitution on the differential cross sections （DCSs） and alignments of the product＇s rotational angular momentum have also been studied. The results suggest that the integral cross sections increase with increasing collision energy, and the vibrational excitation of the reagent has great influence on the DCS. In addition, the product＇s rotational polarization is very strong as a result of heavy-heavy-light （HHL） mass combination, and the distinct effect of isotope substitution on the stereodynamics is also revealed.展开更多
Urine analysis is one of the most common and useful assay means in clinic for diagnose disease, especially urinary system disease and dry chemistry method is the most convenient, common and low cost about urine analys...Urine analysis is one of the most common and useful assay means in clinic for diagnose disease, especially urinary system disease and dry chemistry method is the most convenient, common and low cost about urine analysis. To expediently and efficiently analyze the corresponding relationships between different color data and semi-quantitative results about every urine item with dry chemistry way, in this paper, the design and application of effective software that may be used to collect color data about urine reagent strips are presented. First, we introduce the design procedure of this software. Second, its realization of design is given. Third, several application examples about collecting RGB original data by RS232 interface are shown. Then, RGB original data can be visually displayed by waveforms or curves and the data of cursor position may also be given. From the examples, we could confidently draw a conclusion that it is very convenient and effective to study on the laws of color variation about reagent pieces on reagent strip and it has met our original designed demands.展开更多
In the early days of deciphering the injured neuronal tissues led to the realization that contrast is necessary to discern the parts of the recovering tissues from the damaged ones.Early attempts relied on available(a...In the early days of deciphering the injured neuronal tissues led to the realization that contrast is necessary to discern the parts of the recovering tissues from the damaged ones.Early attempts relied on available(and often naturally occurring)staining substances.Incidentally,the active ingredients of most of them were small molecules.With the advent of time,the knowledge of chemistry helped identify compounds and conditions for staining.The staining reagents were even found to enhance the visibility of the organelles.Silver impregnation identification of Golgi bodies was discovered in owl optic nerve.Staining reagents since the late 1800s were widely used across all disciplines and for nerve tissue and became a key contributor to advancement in nerve-related research.The use of these reagents provided insight into the organization of the neuronal tissues and helped distinguish nerve degeneration from regeneration.The neuronal staining reagents have played a fundamental role in the clinical research facilitating the identification of biological mechanisms underlying eye and neuropsychiatric diseases.We found a lack of systematic description of all staining reagents,whether they had been used historically or currently used.There is a lack of readily available information for optimal staining of different neuronal tissues for a given purpose.We present here a grouping of the reagents based on their target location:(I)the central nervous system(CNS),(II)the peripheral nervous system(PNS),or(III)both.The biochemical reactions of most of the staining reagents is based on acidic or basic pH and specific reaction partners such as organelle or biomolecules that exists within the given tissue type.We present here a summary of the chemical composition,optimal staining condition,use for given neuronal tissue and,where possible,historic usage.Several biomolecules such as lipids and metabolites lack specific antibodies.Despite being non-specific the reagents enhance contrast and provide corroboration about the microenvironment.In future,these reagents in combination with emerging techniques such as imaging mass spectrometry and kinetic histochemistry will validate or expand our understanding of localization of molecules within tissues or cells that are important for ophthalmology and vision science.展开更多
文摘A selective and new spectrophotometric method is described for determination of five 1,4 dihydropyridine drugs (1,4- DHP);namely nifedipine (NIF), nicardipine (NIC), nimodipine (NIM), felodipine (FEL) and amlodipine (AML). The method is based on a coupling reaction between the cited drugs and vanillin reagent in acidic condition. Under optimized conditions, the red coloured products were measured at 500 nm for NIF, NIC, NIM and FEL or at 479 nm for AML. Molar absorptivities were ranged from 0.575 × 104 - 1.065 × 104 l·mol-1·cm-1, Beer’s law was obeyed at 5 - 70 μg/mL concentration range and the limit of detection was ranged from 0.150 - 1.500 μg/mL. The proposed method was successfully extended to pharmaceutical preparations tablets and capsules and comparison by Student’s t-test and variance ratio F-test showed no significant difference.
文摘This paper is one of a series of reports of theoretical researches on the mechanism of the Mannich reaction using the iminium salt as the potential Mannich reagent. According to the results of AM1 dynamic calculations, the activation energies of key steps in conventional Mannich reactions between ammonia, formaldehyde and acetaldehyde in neutral and acidic media are 438 8 kJ/mol and 393 9 kJ/mol respectively. The activation energy of the rate controlling step of the Mannich reaction which contains the potential Mannich reagent is 274 7 kJ/mol. Therefore, it can be derived that the potential Mannich reagent can increase the rate of the reaction remarkably. The reasons for this have been discussed in terms of the orbital match and electrostatic interaction between the atoms of reactant complexes. In this paper another different conjectured mechanism of the potential Mannich reagent which can reduce the activation energy is considerably studied.
文摘Based on an extended London-Eyring-Polanyi-Sato （LEPS） potential energy surface （PES）, the Ba q-HF reaction has been studied by the quasi-classical trajectory （QCT） method. The reaction integral cross section as a function of collision energy for the Ba q- HF --＊ BaF q- H reaction is presented and the influence of isotope substitution on the differential cross sections （DCSs） and alignments of the product＇s rotational angular momentum have also been studied. The results suggest that the integral cross sections increase with increasing collision energy, and the vibrational excitation of the reagent has great influence on the DCS. In addition, the product＇s rotational polarization is very strong as a result of heavy-heavy-light （HHL） mass combination, and the distinct effect of isotope substitution on the stereodynamics is also revealed.
文摘Urine analysis is one of the most common and useful assay means in clinic for diagnose disease, especially urinary system disease and dry chemistry method is the most convenient, common and low cost about urine analysis. To expediently and efficiently analyze the corresponding relationships between different color data and semi-quantitative results about every urine item with dry chemistry way, in this paper, the design and application of effective software that may be used to collect color data about urine reagent strips are presented. First, we introduce the design procedure of this software. Second, its realization of design is given. Third, several application examples about collecting RGB original data by RS232 interface are shown. Then, RGB original data can be visually displayed by waveforms or curves and the data of cursor position may also be given. From the examples, we could confidently draw a conclusion that it is very convenient and effective to study on the laws of color variation about reagent pieces on reagent strip and it has met our original designed demands.
基金supported by an unrestricted grant from Research to Prevent Blindness and NIH grants EY14801,EY031292.
文摘In the early days of deciphering the injured neuronal tissues led to the realization that contrast is necessary to discern the parts of the recovering tissues from the damaged ones.Early attempts relied on available(and often naturally occurring)staining substances.Incidentally,the active ingredients of most of them were small molecules.With the advent of time,the knowledge of chemistry helped identify compounds and conditions for staining.The staining reagents were even found to enhance the visibility of the organelles.Silver impregnation identification of Golgi bodies was discovered in owl optic nerve.Staining reagents since the late 1800s were widely used across all disciplines and for nerve tissue and became a key contributor to advancement in nerve-related research.The use of these reagents provided insight into the organization of the neuronal tissues and helped distinguish nerve degeneration from regeneration.The neuronal staining reagents have played a fundamental role in the clinical research facilitating the identification of biological mechanisms underlying eye and neuropsychiatric diseases.We found a lack of systematic description of all staining reagents,whether they had been used historically or currently used.There is a lack of readily available information for optimal staining of different neuronal tissues for a given purpose.We present here a grouping of the reagents based on their target location:(I)the central nervous system(CNS),(II)the peripheral nervous system(PNS),or(III)both.The biochemical reactions of most of the staining reagents is based on acidic or basic pH and specific reaction partners such as organelle or biomolecules that exists within the given tissue type.We present here a summary of the chemical composition,optimal staining condition,use for given neuronal tissue and,where possible,historic usage.Several biomolecules such as lipids and metabolites lack specific antibodies.Despite being non-specific the reagents enhance contrast and provide corroboration about the microenvironment.In future,these reagents in combination with emerging techniques such as imaging mass spectrometry and kinetic histochemistry will validate or expand our understanding of localization of molecules within tissues or cells that are important for ophthalmology and vision science.
