The essential toxin: impact of zinc on human health Plum, Laura M; Rink, Lothar; Haase, Hajo
International journal of environmental research and public health,
04/2010, Volume:
7, Issue:
4
Journal Article
Peer reviewed
Open access
Compared to several other metal ions with similar chemical properties, zinc is relatively harmless. Only exposure to high doses has toxic effects, making acute zinc intoxication a rare event. In ...addition to acute intoxication, long-term, high-dose zinc supplementation interferes with the uptake of copper. Hence, many of its toxic effects are in fact due to copper deficiency. While systemic homeostasis and efficient regulatory mechanisms on the cellular level generally prevent the uptake of cytotoxic doses of exogenous zinc, endogenous zinc plays a significant role in cytotoxic events in single cells. Here, zinc influences apoptosis by acting on several molecular regulators of programmed cell death, including caspases and proteins from the Bcl and Bax families. One organ where zinc is prominently involved in cell death is the brain, and cytotoxicity in consequence of ischemia or trauma involves the accumulation of free zinc. Rather than being a toxic metal ion, zinc is an essential trace element. Whereas intoxication by excessive exposure is rare, zinc deficiency is widespread and has a detrimental impact on growth, neuronal development, and immunity, and in severe cases its consequences are lethal. Zinc deficiency caused by malnutrition and foods with low bioavailability, aging, certain diseases, or deregulated homeostasis is a far more common risk to human health than intoxication.
When taxa go extinct, unique evolutionary history is lost. If extinction is selective, and the intrinsic vulnerabilities of taxa show phylogenetic signal, more evolutionary history may be lost than ...expected under random extinction. Under what conditions this occurs is insufficiently known. We show that late Cenozoic climate change induced phylogenetically selective regional extinction of northern temperate trees because of phylogenetic signal in cold tolerance, leading to significantly and substantially larger than random losses of phylogenetic diversity (PD). The surviving floras in regions that experienced stronger extinction are phylogenetically more clustered, indicating that non‐random losses of PD are of increasing concern with increasing extinction severity. Using simulations, we show that a simple threshold model of survival given a physiological trait with phylogenetic signal reproduces our findings. Our results send a strong warning that we may expect future assemblages to be phylogenetically and possibly functionally depauperate if anthropogenic climate change affects taxa similarly.
When discussing the transition to palliative care for patients with breast cancer, oncologists have to find a balance between giving explicit information while not overwhelming patients and being ...realistic while remaining hopeful. It is unclear whether patients prefer more or less explicit prognostic information, and reassuring patients that they will not be abandoned may provide realistic hope. We assessed the effect of explicit prognostic information and reassurance about nonabandonment at the transition to palliative care.
An experimental 2 × 2 study was used. Four scripted videos of a bad news conversation were created that differed only in the level of "explicitness of prognosis" and "reassurance about nonabandonment" (high v low). Patients with and survivors of breast cancer (n = 51) and healthy women (n = 53) watched the video-vignettes. The effects of the different communications on participants' anxiety, uncertainty, self-efficacy, and satisfaction were assessed by using multilevel analyses that explored the moderating influences of monitoring/blunting scores.
The highly explicit/highly reassuring video yielded the most positive outcomes, and the less explicit/less reassuring video, the most negative (P ≤ .05 for all outcome measures except anxiety). The main effects found were that explicitness and reassurance decreased participants' uncertainty (P < .001 and P = .002, respectively) and anxiety (only after reassurance; P = .001) while increasing self-efficacy (P = .004 and P < .001, respectively) and satisfaction (P < .001 and P < .001, respectively). High monitors seemed least positive, mainly following explicitness.
Explicit prognostic information may lead to better outcomes than general information. In addition, reassurance about nonabandonment might provide realistic hope but should be lived up to. More research is needed to translate these findings into clinical care.
Quality of life is an important end point in clinical trials, yet there are few quality of life questionnaires for neuroendocrine tumours.
This international multicentre validation study assesses the ...QLQ-GINET21 Quality of Life Questionnaire in 253 patients with gastrointestinal neuroendocrine tumours. All patients were requested to complete two quality of life questionnaires - the EORTC Core Quality of Life questionnaire (QLQ-C30) and the QLQ-GINET21 - at baseline, and at 3 and 6 months post-baseline; the psychometric properties of the questionnaire were then analysed.
Analysis of QLQ-GINET21 scales confirmed appropriate aggregation of the items, except for treatment-related symptoms, where weight gain showed low correlation with other questions in the scale; weight gain was therefore analysed as a single item. Internal consistency of scales using Cronbach's α coefficient was >0.7 for all parts of the QLQ-GINET21 at 6 months. Intraclass correlation was >0.85 for all scales. Discriminant validity was confirmed, with values <0.70 for all scales compared with each other.Scores changed in accordance with alterations in performance status and in response to expected clinical changes after therapies. Mean scores were similar for pancreatic and other tumours.
The QLQ-GINET21 is a valid and responsive tool for assessing quality of life in the gut, pancreas and liver neuroendocrine tumours.
The Spallation Neutron Source (SNS) at ORNL currently is being upgraded from 1.0 GeV to 1.3 GeV. Several water-cooled magnets should be upgraded to transport 30% of higher beam energy. New chicane, ...injection/extraction septum, and Lambertson magnets were designed. Designing the magnets was a challenging task because the new magnets required good combined integrated field quality and needed to occupy the old magnets space but with about 20% greater integrated magnetic field. Additional strong requirements applied to the magnets fringe field do not disturb the circulating beam. The special field profiles had to be provided in foil areas between magnets. The analysis described here was based on OPERA3D simulations. A special technique was used for analyzing the integrated field harmonics. Initially, the particle track was simulated, and integrated field components were calculated along this track for the reference radius, which were used for the harmonics analysis. In addition, 3D field maps were provided for beam optics simulations. The final beamline analysis confirmed good beam transmission and low losses.
•A novel formulation of the liner shipping network design problem.•The first model to fully handle butterfly ports, having multiple calls to the multiple ports, often used in practice.•Results are ...reported for the LINER-LIB benchmark suite.
Global liner shipping is a competitive industry, requiring liner carriers to carefully deploy their vessels efficiently to construct a cost competitive network. This paper presents a novel compact formulation of the liner shipping network design problem (LSNDP) based on service flows. The formulation alleviates issues faced by arc flow formulations with regards to handling multiple calls to the same port. A problem which has not been fully dealt with earlier by LSNDP formulations. Multiple calls are handled by introducing service nodes, together with port nodes in a graph representation of the problem, and by introducing numbered arcs between a port and a novel service node. An arc from a port node to a service node indicate whether a service is calling the port or not. This representation allows recurrent calls of a service to a port, which previously could not be handled by LSNDP models. The model ensures strictly weekly frequencies of services, ensures that port-vessel draft capabilities are not violated, respects vessel capacities and the number of vessels available. The profit of the generated network is maximized, i.e. the revenue of flowed cargo subtracted operational costs of the network and a penalty for not flowed cargo. The model can be used to design liner shipping networks to utilize a container carrier’s assets efficiently and to investigate possible scenarios of changed market conditions. The model is solved as a Mixed Integer Program. Results are presented for the two smallest instances of the benchmark suite LINER-LIB-2012 presented in Brouer, Alvarez, Plum, Pisinger, and Sigurd (2013).
► A MIP model describing the recovery of a delayed container vessel is developed. ► Model finds improved solutions on real life cases. ► Three recovery options are considered: speed adjustment, port ...call omission and port call swap. ► Model can enable vessel operators to take optimal decisions, fast. ► Problem is NP-complete.
Containerized transport by liner shipping companies is a multi billion dollar industry carrying a major part of the world trade between suppliers and customers. The liner shipping industry has come under stress in the last few years due to the economic crisis, increasing fuel costs, and capacity outgrowing demand. The push to reduce CO2 emissions and costs have increasingly committed liner shipping to slow-steaming policies. This increased focus on fuel consumption, has illuminated the huge impacts of operational disruptions in liner shipping on both costs and delayed cargo. Disruptions can occur due to adverse weather conditions, port contingencies, and many other issues. A common scenario for recovering a schedule is to either increase the speed at the cost of a significant increase in the fuel consumption or delaying cargo. Advanced recovery options might exist by swapping two port calls or even omitting one. We present the Vessel Schedule Recovery Problem (VSRP) to evaluate a given disruption scenario and to select a recovery action balancing the trade off between increased bunker consumption and the impact on cargo in the remaining network and the customer service level. It is proven that the VSRP is NP-hard. The model is applied to four real life cases from Maersk Line and results are achieved in less than 5seconds with solutions comparable or superior to those chosen by operations managers in real life. Cost savings of up to 58% may be achieved by the suggested solutions compared to realized recoveries of the real life cases.
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