Recovery Degree of the Natural Flow Regimes and the Corresponding Economic Costs for Reservoir Operation in Fish Spawning Seasons.

The construction of large-scale reservoirs alters the natural flow process downstream and inevitably affects the aquatic organism. Current studies have verified that flow regimes play an important role in fish spawning stimulus. Recovery of the flow regimes may be incompatible with the economic benefit, mainly referring to hydropower generation. In this study, multiple models are established to study the relationship between the recovery degree of the natural flow regimes and the cost of the hydropower generation in spawning season for different hydrological years. The flow regimes are first quantitatively described by three characteristic parameters including the number of floods, the average duration of each flood, and the daily increment of the natural flow. The model for ecological operation needs to approach these characteristics as close as possible, while the model for economic benefit is set to generate power as much as possible. The ecological flow constraint is also considered to shape the flow process pattern. The proposed methodology is applied on the upper reaches of the Yellow River, where a large-scale reservoir is under planning. Different schemes are compared for different hydrological years to answer the question that to what extent can we recover the flow regime by reservoir operation, and how much the corresponding economic cost is.

Research progress on the relationship between zinc deficiency, related microRNAs, and esophageal carcinoma.

Esophageal cancer (EC) is a common malignant tumor of the gastrointestinal tract with a high incidence in China. Zinc (Zn) deficiency is a key risk factor for the occurrence and development of EC and affects progression by regulating microRNA (miRNA, miR) expression. In addition, the dysregulation of miRNAs is accompanied by the dysregulation of their target genes in EC. In this paper, we review the potential molecular mechanisms between Zn deficiency and EC with the aim of providing new strategies and methods for early diagnosis, targeted therapy, and prognostic evaluation.

Development and in vitro evaluation of a transdermal hydrogel patch for ferulic acid.

Current work aimed to develop and evaluate a transdermal delivery system of hydrogel patch for ferulic acid to treat skin damage induced by UV radiation. VISCOMATE(TM) NP700, dihydroxy aluminium aminoacetate, glycerine, tartaric acid were used in combination in different ratios to design the hydrogel patch. In vitro release rate was selected as an index to optimize the formulation. The formulated hydrogel patch was evaluated by several parameters like tacking strength, cohesive strength, peeling strength, residuals after peeling and drug content determination. The in vitro penetration was determined by Franz diffusion technology with hairless mouse skin as permeability media. Different kinetics models were employed to simulate the release and penetrate patterns of ferulic acid from patches in order to investigate the drug transport mechanism. The residual drugs in the patch and skin were determined after the penetration experiment. The optimized preparation was dihydroxy aluminium aminoacetate: NP700: glycerine: ferulic acid as a ratio of 0.02:0.4:1.5:1.25:0.25. The cumulative percentage of release was 60.4465±1.7679% for 24h, which results from a combination of diffusion effect and polymer erosion effect. For the barrier of stratum corneum, the cumulative penetrate rate was only 1.3156±0.3588% and the release mechanism turn out to be the effect of erosion of polymer surface. The residual drugs in the patch were 97.5949±1.4932%. The in vitro data revealed that it was easy for ferulic acid to release from the paste while difficult to permeate through the skin barrier, which resulted in most of drugs residued in the paste. Hence, further experiments will be necessary for finding the penetration enhancer in ferulic acid transdermal delivery.

[Study on in vitro penetration of imperatorin].

The object of this paper was to study the in vitro percutaneous factors that affect permeability of imperatorin. Excised abdominal skin of SD rats was used as the permeation model. Modified Franz diffusion cell was used to evaluate receiving solution, skin treatment and drug concentration on the effect of permeation. HPLC was established to determine drug content in recetpor at specified time points. The result showed that 20% ethanol and 0.5% Tween-80 could significantly increase the steady-state infiltration rate (Jass) of imperatorin. Skin treated of 20% ethanol, 20% ethanol-1% Tween-80 before experiments got an increased transdermal rate, whereas, those only accepted the treatment of 1% Tween-80 showed a decreased transdermal rate. The steady-state infiltration rate of imperatorin had a relationship with drug concentration, with the concentration increase, a bigger steady-state infiltration rate was obtained. When the drug concentration reached a certain concentration, the value was no longer changed. From the above research it could be found that ethanol could change the structure of the skin stratum corneum, which resulted in the increase of steady-state infiltration rate. The effect of Tween-80 on the steady-state permeation rate had nothing to do with skin structure. The concentration of drug in the diffusing cell had an effect on the penetration of imperatorin, which was the combined action of different diffusion route.

[Study on transdermal behavior of Zhitong cataplasm].

The aim of the present research was to study the transdermal absorbability of ferulic acid and imperatorin in Zhitong cataplasm. Using methanol to extract the effective components, HPLC was established to determine drug content in Zhitong cataplasm. The excised abdominal skin of nude rats was used as the permeation model Utilizing the modified Franz diffusion cell, the suitable receiving solution was elected. The contents of ferulic acid and imperatorin in Zhitong cataplasm were 455.10, 371.66 microg x g(-1), respectively. Taken 20% ethanol- PBS (pH 8) as receiving solution, ferulic acid and imperatorin could be detected maximize, with the steady-state infiltration rates of 1.29, 0.15 microg x h(-1) x cm(-2), respectively. After 24 h, their penetration quantities were 30.03, 3.31 microg x cm(-2), with the penetration rates of 41.45%, 5.60%, respectively. The residual quantities of ferulic acid and imperatorin in skin were 0.69, 2.60 microg x cm(-2), with the retention rates of 0.95%, 4.40%, respectively. The in vitro transdermal behavior of ferulic acid in Zhitong cataplasm was close to a zero-order process, with the stratum corneum playing a rate-limiting role; whereas the percutaneous behavior of imperatorin was closer to Higuchi model, where diffusion played an important role in drugs permeation.

[Pharmacokinetics of ferulic acid in transdermal delivery].

OBJECTIVE: To study the pharmacokinetics of ferulic acid in transdermal delivery; the influence factors such as temperature, flow rate, and drug concentration on the probe recovery are also investigated to obtain accurate data. METHOD: The stability of in vitro and in vivo recovery was determined by loss but the influence factor on the recovery was determined by gain. Appling dermal microdialysis to ferulic acid analytes, the concentration of ferulic acid in the dialysate was detected by HPLC. RESULT: There is a significant effect on the probe recovery for the in vitro recovery is much bigger at a higher temperature. When the flow rate rises, the in vitro recovery is down at index rate instead. Within the measuring rage, the drug concentration doesn't have effect on the recovery. The steady and reproduce of recovery is well within the measuring time, and the average recovery of in vitro is (24.82 +/- 1.01)% without temperature control and in vivo is (16.50 +/- 1.92)%. The C(max) of ferulic acid is 86 min and MRT is 291 min after dermal administration. CONCLUSION: Dermal microdialyis can be used in the ferulic acid study. For the ferulic acid can permeate the corneum quciky, it is practical to develop a transdermal delivery.

[Study on in vitro/in vivo correlation of extracts from Ligusticum chuanxiong after transdermal administration].

OBJECTIVE: To study the transdermal permeation and in vivo pharmacokinetics of effective constituent ferulic acid from Ligusticum chuanxiong, in order to establish the in vitro/in vivo correlation in transdermal permeation. METHOD: Franz diffusion cell was adopted in the in vitro transdermal permeation, with CD-1 nude rat abdominal skin as the permeation medium. Linear probes were implanted in CD-1 nude rats. With PBS as perfusate, microdialysis was employed to study the pharmacokinetics. Ferulic acid concentrations in the receptor solution and dialysate were assessed by high performance liquid chromatography (HPLC). The study on correlation between in vitro and in vivo data was conducted by deconvolution methods. RESULT: The transdermal permeation rate of ferulic acid from Ligusticum chuanxiong was (0.094 4 +/- 0.049 4) microg x cm2 x min, with Cmax of ferulic acid being 808.91 microg x L(-1), and Tmax being 183 min after dermal administration. The in vitro/in vivo correlation was 93.61. CONCLUSION: Ferulic acid in extracts from L. chuanxiong can quickly penetrate skins. By using the in vitro/in vivo correlation in transdermal permeation, simple in vitro transdermal permeation method can be adopted to study the changes in its pharmacokinetics.