Biofouling is an important problem for reverse osmosis (RO) membrane manufacturers. Bacteria are mainly involved in generating fouling and obturating RO membranes. Insights into biofilm bacteria composition could help...Biofouling is an important problem for reverse osmosis (RO) membrane manufacturers. Bacteria are mainly involved in generating fouling and obturating RO membranes. Insights into biofilm bacteria composition could help prevent biofouling, reduce the cost of using RO-fouling membranes and guarantee safe water. Culture-dependent and independent techniques were then performed in order to identify bacteria associated with RO membranes. Bacteria cultures described the presence of six pure colonies, four of which were identified through API testing. Based on 16s rRNA gene analysis, a predominant bacterium was identified and annotated as Sphingomonas sp. The 16s rRNA gene clone library, on the other hand, showed that the bacterium, Pseudomonas marincola, accounted for nearly 30% of the clone library, while the rest of bacteria were chimeras (62%) and non-representative species (3%). In conclusion, culture-dependent and independent approaches showed that two dominant bacteria were commonly observed in RO desalination membranes.展开更多
This work presents a simple and sensitive flow injection fluorimetric method for the determination of carbamazepine (CBZ) in pharmaceutical samples. It is based on the fluorescence signal measurement of the product ge...This work presents a simple and sensitive flow injection fluorimetric method for the determination of carbamazepine (CBZ) in pharmaceutical samples. It is based on the fluorescence signal measurement of the product generated by photoinduced (λex = 251 nm;λem = 434 nm) using a flow injection manifold containing an online homemade photoreactor. In order to optimize the experimental setup, the variable conditions were studied using a multivariate optimization method, thus finding the set of optimum parameters according to the evaluated responses (sensitivity and sampling frequency) and minimizing the number of experiments performed. Under optimal experimental conditions, linear relationship with good correlation coefficient (0.9956) was found between the fluorescence intensity and CBZ concentration in the range of 0.13 - 40 μg·mL-1. The limit of detection was 0.04 μg·mL-1. The precision of the method was satisfactory;the values of relative standard deviations were better than 4.36%. The proposed method was validated and successfully applied to the determination of CBZ in pharmaceuticals with good accuracy;being the recovery values from 89.45% - 112.20%.展开更多
The sanitary and environmental challenges posed by an ever growing economically and geographically diverse human population include the need for sustainable, inexpensive, scalable, and decentralized water treatment te...The sanitary and environmental challenges posed by an ever growing economically and geographically diverse human population include the need for sustainable, inexpensive, scalable, and decentralized water treatment technologies that can supplement or replace conventional treatment methods. These challenges can be met by semiconductor photocatalysis, especially if the process is driven by visible light energy. Visible-light active (VLA) photocatalysis, as opposed to traditional energy-intensive and chemically driven disinfection methods such as ozonation, UV irradiation and chlorination, has the potential for achieving high disinfection efficiency with low energy consumption and no harmful by-products. This technology generates in-situ reactive oxygen species (ROS) such as H2O2, and?, without the need for chemicals addition. In turn, ROS are capable of penetrating cell walls and membranes of microorganisms, effectively inactivating them. Although multiple types of VLA photocatalysts have been used experimentally for disinfection of water, noble-metal-based photocatalysts have gained the most interest due to their surface plasma resonance (SPR) effect, which acts synergistically to increase the disinfection potential of the photocatalytic process. This paper is a review of the different types of noble-metal-based VLA photocatalysts used for water disinfection in different experimental settings, their synthesis procedures and disinfection mechanisms. It also discusses innovative approaches to overcome a major hurdle in photocatalysis, that is, the rapid recombination of the electron and hole pair, by including specific dopants into the structure of the photocatalyst.展开更多
Aim: To develop a simple and sensitive high-performance liquid chromatography method to determine plasmatic levels of trimethoprim/sulfamethoxazole in paediatric population. Method: Chromatographic separation was carr...Aim: To develop a simple and sensitive high-performance liquid chromatography method to determine plasmatic levels of trimethoprim/sulfamethoxazole in paediatric population. Method: Chromatographic separation was carried out using a reverse phase column with detection ultraviolet at a wavelength of 225 nm. The mobile phase consists of phosphate buffer 0.1 M, acetonitrile and methanol, (65:20:15) with a flow of 1.0 ml/min. Results: Calibration curve was linear over the concentration range for trimethoprim of 0.25 to 5 μg/ml and 5 to 100 μg/ml for sulfamethoxazole. Precision were found to be within 15% for both compounds. The detection limits and quantifications for trimethoprim/sulfamethoxazole were 0.2 - 0.25 μg/ml and 3 - 5 μg/ml respectively. Conclusions: The developed method was applied for the quantification of both compounds in plasma samples of two patients resulting concentrations within the therapeutic ranges. The method is convenient for pharmacokinetic studies.展开更多
Abdominal epilepsy is often unrecognised as an epilepsy condition, particularly in adults. We present a rare adult patient who suffers daily episodes of abdominal pinching pain described lasting for 30 seconds, often ...Abdominal epilepsy is often unrecognised as an epilepsy condition, particularly in adults. We present a rare adult patient who suffers daily episodes of abdominal pinching pain described lasting for 30 seconds, often evolving to loss of consciousness. Scalp EEG-video monitoring showed interictal left temporal slowing and frequent left temporal epileptiform discharges. Three stereotypical complex partial seizures consistent with her habitual attacks were recorded. Two seizures showed a left temporal onset and whereas the third one appeared to start on the right temporal lobe. In patients with paroxysms of abdominal pain, nausea or vomiting, abdominal epilepsy should be considered after exclusion of the most common aetiologies for gastrointestinal conditions.展开更多
The study of the triacylglycerols (TAG) by gas chromatography (GC) using capillary columns is an efficient technique for the determination of some characteristics of quality of fats and oils. The objective of the pres...The study of the triacylglycerols (TAG) by gas chromatography (GC) using capillary columns is an efficient technique for the determination of some characteristics of quality of fats and oils. The objective of the present study was to determine by GC the content of TAG present in fat of cow and goat milk produced in four zones of Mexico. According to criteria established in Mexican Standardization, 25 samples were obtained of 1 L of ultra-pasteurized cow milk (UHT) and 27 and 48 of raw cow and goat milk, respectively. The fat was extracted from all of the milk samples by detergent solution, and was stored at –20℃ until its analysis. The chromatographic conditions made it possible to identify and quantify TAG of 28 to 54 numbers of carbons, which were analyzed under descriptive and inferential statistical techniques. For the cow milk fat, the statistical analyses indicated significant difference (p < 0.05) in the TAG C34, C50 and C52, and for the goat milk fat in the TAG of C36 to C52. No equality of means was found among the TAG of the cow and goat milk fat. This study offers an advance in the characterization of the TAG present in the cow and goat milk fat produced in Mexico.展开更多
在液体培养基中加入ANC或PBZ等生长延缓剂可有效控制香蕉组培中过多的茎干和叶片的数量。可是，这些化学药剂对香蕉今后的生长有何影响尚未弄清。为了了解ANC和PBZ对Grand Nain品种球茎的影响，委内瑞拉的Albany N R等人将香蕉的增殖过...在液体培养基中加入ANC或PBZ等生长延缓剂可有效控制香蕉组培中过多的茎干和叶片的数量。可是，这些化学药剂对香蕉今后的生长有何影响尚未弄清。为了了解ANC和PBZ对Grand Nain品种球茎的影响，委内瑞拉的Albany N R等人将香蕉的增殖过程分为5个阶段，研究了其根伸长阶段和环境适应阶段。展开更多
文摘Biofouling is an important problem for reverse osmosis (RO) membrane manufacturers. Bacteria are mainly involved in generating fouling and obturating RO membranes. Insights into biofilm bacteria composition could help prevent biofouling, reduce the cost of using RO-fouling membranes and guarantee safe water. Culture-dependent and independent techniques were then performed in order to identify bacteria associated with RO membranes. Bacteria cultures described the presence of six pure colonies, four of which were identified through API testing. Based on 16s rRNA gene analysis, a predominant bacterium was identified and annotated as Sphingomonas sp. The 16s rRNA gene clone library, on the other hand, showed that the bacterium, Pseudomonas marincola, accounted for nearly 30% of the clone library, while the rest of bacteria were chimeras (62%) and non-representative species (3%). In conclusion, culture-dependent and independent approaches showed that two dominant bacteria were commonly observed in RO desalination membranes.
文摘This work presents a simple and sensitive flow injection fluorimetric method for the determination of carbamazepine (CBZ) in pharmaceutical samples. It is based on the fluorescence signal measurement of the product generated by photoinduced (λex = 251 nm;λem = 434 nm) using a flow injection manifold containing an online homemade photoreactor. In order to optimize the experimental setup, the variable conditions were studied using a multivariate optimization method, thus finding the set of optimum parameters according to the evaluated responses (sensitivity and sampling frequency) and minimizing the number of experiments performed. Under optimal experimental conditions, linear relationship with good correlation coefficient (0.9956) was found between the fluorescence intensity and CBZ concentration in the range of 0.13 - 40 μg·mL-1. The limit of detection was 0.04 μg·mL-1. The precision of the method was satisfactory;the values of relative standard deviations were better than 4.36%. The proposed method was validated and successfully applied to the determination of CBZ in pharmaceuticals with good accuracy;being the recovery values from 89.45% - 112.20%.
文摘The sanitary and environmental challenges posed by an ever growing economically and geographically diverse human population include the need for sustainable, inexpensive, scalable, and decentralized water treatment technologies that can supplement or replace conventional treatment methods. These challenges can be met by semiconductor photocatalysis, especially if the process is driven by visible light energy. Visible-light active (VLA) photocatalysis, as opposed to traditional energy-intensive and chemically driven disinfection methods such as ozonation, UV irradiation and chlorination, has the potential for achieving high disinfection efficiency with low energy consumption and no harmful by-products. This technology generates in-situ reactive oxygen species (ROS) such as H2O2, and?, without the need for chemicals addition. In turn, ROS are capable of penetrating cell walls and membranes of microorganisms, effectively inactivating them. Although multiple types of VLA photocatalysts have been used experimentally for disinfection of water, noble-metal-based photocatalysts have gained the most interest due to their surface plasma resonance (SPR) effect, which acts synergistically to increase the disinfection potential of the photocatalytic process. This paper is a review of the different types of noble-metal-based VLA photocatalysts used for water disinfection in different experimental settings, their synthesis procedures and disinfection mechanisms. It also discusses innovative approaches to overcome a major hurdle in photocatalysis, that is, the rapid recombination of the electron and hole pair, by including specific dopants into the structure of the photocatalyst.
文摘Aim: To develop a simple and sensitive high-performance liquid chromatography method to determine plasmatic levels of trimethoprim/sulfamethoxazole in paediatric population. Method: Chromatographic separation was carried out using a reverse phase column with detection ultraviolet at a wavelength of 225 nm. The mobile phase consists of phosphate buffer 0.1 M, acetonitrile and methanol, (65:20:15) with a flow of 1.0 ml/min. Results: Calibration curve was linear over the concentration range for trimethoprim of 0.25 to 5 μg/ml and 5 to 100 μg/ml for sulfamethoxazole. Precision were found to be within 15% for both compounds. The detection limits and quantifications for trimethoprim/sulfamethoxazole were 0.2 - 0.25 μg/ml and 3 - 5 μg/ml respectively. Conclusions: The developed method was applied for the quantification of both compounds in plasma samples of two patients resulting concentrations within the therapeutic ranges. The method is convenient for pharmacokinetic studies.
文摘Abdominal epilepsy is often unrecognised as an epilepsy condition, particularly in adults. We present a rare adult patient who suffers daily episodes of abdominal pinching pain described lasting for 30 seconds, often evolving to loss of consciousness. Scalp EEG-video monitoring showed interictal left temporal slowing and frequent left temporal epileptiform discharges. Three stereotypical complex partial seizures consistent with her habitual attacks were recorded. Two seizures showed a left temporal onset and whereas the third one appeared to start on the right temporal lobe. In patients with paroxysms of abdominal pain, nausea or vomiting, abdominal epilepsy should be considered after exclusion of the most common aetiologies for gastrointestinal conditions.
文摘The study of the triacylglycerols (TAG) by gas chromatography (GC) using capillary columns is an efficient technique for the determination of some characteristics of quality of fats and oils. The objective of the present study was to determine by GC the content of TAG present in fat of cow and goat milk produced in four zones of Mexico. According to criteria established in Mexican Standardization, 25 samples were obtained of 1 L of ultra-pasteurized cow milk (UHT) and 27 and 48 of raw cow and goat milk, respectively. The fat was extracted from all of the milk samples by detergent solution, and was stored at –20℃ until its analysis. The chromatographic conditions made it possible to identify and quantify TAG of 28 to 54 numbers of carbons, which were analyzed under descriptive and inferential statistical techniques. For the cow milk fat, the statistical analyses indicated significant difference (p < 0.05) in the TAG C34, C50 and C52, and for the goat milk fat in the TAG of C36 to C52. No equality of means was found among the TAG of the cow and goat milk fat. This study offers an advance in the characterization of the TAG present in the cow and goat milk fat produced in Mexico.
文摘在液体培养基中加入ANC或PBZ等生长延缓剂可有效控制香蕉组培中过多的茎干和叶片的数量。可是，这些化学药剂对香蕉今后的生长有何影响尚未弄清。为了了解ANC和PBZ对Grand Nain品种球茎的影响，委内瑞拉的Albany N R等人将香蕉的增殖过程分为5个阶段，研究了其根伸长阶段和环境适应阶段。
