Making the Biotic Ligand Model kinetic, easier to develop, and more flexible for deriving water quality criteria.

In aquatic environments, the ecological risks posed by metals are greatly affected by water chemistry, thereby creating challenges for water quality management. Biotic ligand models (BLMs) have become the most widely used tools to interpret and predict water chemistry effects. Traditional BLM development methods require a large number of toxicity tests and organisms, and model predictions are limited to certain toxicity statistics (e.g., 48-h median effective concentration, 48-h EC50), to which the models were calibrated. To address these limitations, we propose a new method to develop BLMs by integrating them into the toxicokinetic-toxicodynamic (TK-TD) framework. Metal bioaccumulation was predicted from metal exposure and water chemistry using the BLM-type toxicokinetics, whilst metal toxicity was predicted from metal bioaccumulation using the toxicodynamics. Using the new method, we developed a kinetic BLM of cadmium for Daphnia magna with only six toxicity tests and 1540 daphnids; this represents a 60-80% reduction compared to the traditional methods. The model was validated in the presence of commercial dissolved organic matter (DOM) and in natural waters sampled from 12 lakes. The kinetic BLM was able to accurately simulate the protective effects of the commercial DOM by employing the Stockholm humic model, whilst the complexation capabilities of some natural DOM were overestimated. We further used the model to predict Cd EC50 and no-effect concentrations for different waters, generating predictions close to the effect concentrations reported in the literature. Overall, our method requires fewer resources and presents an easier approach to develop BLMs; the kinetic BLM is more flexible and can serve as a useful tool for developing water quality criteria.

A solution-processed ternary copper halide thin films for air-stable and deep-ultraviolet-sensitive photodetector.

Recently, the newly emerging lead-halide perovskites have received tremendous attention in the photodetection field because of their intrinsic large light absorption and high well-balanced carrier transport characteristics. Unfortunately, the issue of instability and the existence of toxic lead cations have greatly restricted their practical applications and future commercialization. Furthermore, the previous studies on perovskite photodetectors mainly operate in visible and near-infrared light region, and there are practically no relevant reports aimed at the deep-ultraviolet (DUV) region. In this study, an air-stable and DUV-sensitive photoconductive detector was demonstrated with a solution-processed ternary copper halides Cs3Cu2I5 thin films as the light absorber. The proposed photodetector is very sensitive to wavelengths of light below 320 nm and unresponsive to the visible light. Because of the high material integrity and large surface coverage of the Cs3Cu2I5 thin films, the detector presents an outstanding photodetection performance with a photoresponsivity of ∼17.8 A W-1, specific detectivity of 1.12 × 1012 Jones, and fast response speed of 465/897 µs, superior to previously reported DUV photodetectors based on other material systems. Unlike traditional lead-halide perovskites, the lead-free Cs3Cu2I5 shows remarkable stability against heat, UV light, and environmental oxygen/moisture. Thus, the unsealed photodetector demonstrates good operation stability for 11 h of continuous running in open air. Even after 80-day storage in ambient air, its photodetection capability can nearly be maintained. The results suggest that non-toxic Cs3Cu2I5 could be a potential candidate for stable and environment friendly DUV detectors, enabling an assembly of optoelectronic systems in the future.

[Treatment of depression fractures of posterolateral tibial plateau through a modified anterolateral approach].

OBJECTIVE: To study the therapeutic effects of posterolateral depression fractures of the tibial plateau through a modified anterolateral approach. METHODS: From February 2011 to January 2012,13 patients with posterolateral depression fractures of the tibial plateau were treated through a modified anterolateral approach. There were 8 males and 5 females, ranging in age from 28 to 59 years old (49.2 years old on average). Data from patients were collected retrospectively as follows: X-ray, time of fracture healing and the complications of fracture healing. The patients were evaluated both clinically and radiologically according to the Rasmussen score system. RESULTS: All the patients were followed up, and the duration ranged from 6 to 18 months (mean 13.7 months). All the patients got bony union. The average radiographic bony union time was 15.1 weeks (ranged, 11 to 17 weeks). No case of secondary articular depression was found. No complications such as malunion or joint stiffness were found. But 1 patient had superficial infection and 1 patient had common peroneal nerve injury. According to the Rasmussen score system,the mean radiological score was 16.50 ± 0.67 (ranged, 13 to 18), and the mean functional score was 25.20 ± 2.21 (ranged, 13 to 30). The mean range of knee motion was (125.3 ± 9.3)° (ranged, 0° to 135°). CONCLUSION: Treatment of depression fractures of posterolateral tibial plateau with a modified anterolateral approach is a safe method with effective exposure, due to its stable fixation and relatively good outcome with minimal soft-tissue complications. It is regarded as an ideal procedure for depression fractures of posterolateral tibial plateau.