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The mobility of arsenic (As) in soil depends on its sorption/desorption processes on soil particles. Plant uptake locally lowers As concentration in soil pore water, which would trigger resupplies of As from soil solid phase. To better understand the fate of As in soil system after its inputs into soil and its subsequent dynamic processes, diffusive gradients in thin films (DGT) technique along with DGT-induced fluxes in soils (DIFS) model were introduced to study the kinetic information of As in soils, including its response time (TC) and resupply rate constant (k−1). To achieve a series of soils with gradient As level, two different types of soils with similar As level (total As in soil JL is 7.4 mg kg−1, while in soil BJ is 6.5 mg kg−1) were collected and amended with exogenous As. Then, DGT deployments were carried out following a period of 90-day soil incubation. The simulated TC values in non-amended soil JL and soil BJ were 0.036 and 0.001 s−1, respectively. The difference may due to the properties of these two soils, including pH values and contents of adsorption materials, such as Fe and Al compounds. After As inputs into soils, the intrinsic rate of As release from the solid phase to the solution phase in As-amended JL soil was much higher than that in non-amended soil. While for soil BJ, a decreasing trend was observed after As spiking. The redistribution of As may responsible for the different variation trends of As kinetics in these two soils after As spiking. The results indicated that the distribution coefficient of As (Kd) in soil was mainly affected by soil Olsen-P content due to an ubiquitous competition between P and As on soil particles. [ABSTRACT FROM AUTHOR]

To further enhance the anti- Aspergillus efficacy of our previously discovered antifungal lead compounds ( 1 ), a series of aromatic heterocyclic derivatives were designed, synthesized and evaluated for in vitro antifungal activity. Many of the target compounds showed good inhibitory activity against Candida albicans and Cryptococcus neoformans . In particular, the isoxazole nuclei were more suited for improving the activity against Aspergillus spp . Among these compounds, 2-F substituted analogues 23g and 23h displayed the most remarkable in vitro activity against Candida spp. , C. neoformans , A. fumigatus and fluconazole-resistant C.alb. strains, which is superior or comparable to the activity of the reference drugs fluconazole and voriconazole. Notably, the compounds 23g and 23h exhibited low inhibition profiles for various isoforms of human cytochrome P450 and excellent blood plasma stability. [ABSTRACT FROM AUTHOR]

Fungal infections have became a serious medical problem due to their high incidence and mortality. We describe the discovery and structure-activity relationships studies (SARs) of a series of novel biphenyl imidazole derivatives with excellent antifungal activities against Candida albicans and Cryptococcus neoformans . The most promising compounds 12f – g and 19a – b exhibited excellent activity with minimum inhibitory concentration (MIC) values in the range of 0.03125–2 μg/mL. Preliminary mechanism studies showed that the potent antifungal activity of compound 12g stemed from inhibition of CYP51 in Candida albicans . Furthermore, compounds 12g and 19b exhibited low inhibition profiles for various human cytochrome P450 isoforms. The SARs and binding mode established in this study will be useful for further lead optimization. [ABSTRACT FROM AUTHOR]

Wearing of vehicle parts could release many chemical additives into the environment, such as benzotriazoles (BTRs), benzothiazoles (BTHs), and p -phenylenediamines (PPDs), which are potentially toxic to wildlife and humans. This study investigated the occurrence, source, and risks of BTRs, BTHs, and PPDs in a source catchment providing water to Guangzhou, a megacity in South China, covering groundwater, surface water, and stormwater. The results showed that BTRs and BTHs were predominant in surface water and groundwater. Unexpectedly, the BTR and BTH concentrations were lower in surface water than groundwater in a third of the paired samples. For the first time, 6PPD-quinone, a toxic ozonation product of N -(1,3-dimethylbutyl)- N′ -phenyl-1,4-phenylenediamine (6PPD), was extensively detected in source waters. Stormwater decreased the BTR concentrations but increased the 6PPD-quinone concentrations in surface water owing to their affiliation to suspended particles. From natural to urban segments of Liuxi river, a downstream increasing trend in BTR and BTH concentrations was observed, confirming that they are indicative of urban anthropogenic activities. Strong correlations between industrial activities and BTR or BTH concentrations in surface water indicated that industrial activities were their main sources. Six compounds were prioritized as potentially persistent, mobile, and toxic (PMT) chemicals, combing our monitoring results and REACH criterion. This study improves our understanding of the environmental fates and risks of water-soluble tire-wear chemicals, which provides important information for chemical management, and indicates attention should be paid to the risk posed by 6PPD-quinone in the source water. [Display omitted] • For the first time, 6PPD-Q was widely detected in source water, and could pose high risks via drinking water. • Six compounds, including 6PPD-quinone, were identified as potentially persistent, mobile and toxic (PMT) substances. • BTRs and BTHs are demonstrated to be indicators of urban anthropogenic activities. [ABSTRACT FROM AUTHOR]

A series of compounds with benzothiazole and amide-imidazole scaffolds were designed and synthesized to combat the increasing incidence of drug-resistant fungal infections. The antifungal activity of these compounds was evaluated in vitro , and their structure-activity relationships (SARs) were evaluated. The synthesized compounds showed excellent inhibitory activity against Candida albicans and Cryptococcus neoformans . The most potent compounds 14o , 14p , and 14r exhibited potent activity, with minimum inhibitory concentration (MIC) values in the range of 0.125–2 μg/mL. Preliminary mechanism studies revealed that the compound 14p might act by inhibiting the CYP51 of Candida albicans . The SARs and binding mode established in this study are useful for further lead optimization. [ABSTRACT FROM AUTHOR]

In this paper, we study the problem of link scheduling for multi-hop wireless networks with per-flow delay constraints under the K-hop interference model. Specifically, we are interested in algorithms that maximize the asymptotic decay-rate of the probability with which the maximum end-to-end backlog among all flows exceeds a threshold, as the threshold becomes large. We provide both positive and negative results in this direction. By minimizing the drift of the maximum end-to-end backlog in the converge-cast on a tree, we design an algorithm, Largest-Weight-First (LWF), that achieves the optimal asymptotic decay-rate for the overflow probability of the maximum end-to-end backlog as the threshold becomes large. However, such a drift minimization algorithm may not exist for general networks. We provide an example in which no algorithm can minimize the drift of the maximum end-to-end backlog. Finally, we simulate the LWF algorithm together with a well known algorithm (the back-pressure algorithm) and a large-deviations optimal algorithm in terms of the sum-queue (the P-TREE algorithm) in converge-cast networks. Our simulation shows that our algorithm performs significantly better not only in terms of asymptotic decay-rate, but also in terms of the actual overflow probability. [ABSTRACT FROM AUTHOR]