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1.

Background

There are many barriers to patient participation in randomised controlled trials of cancer treatments. To increase participation in trials, strategies need to be identified to overcome these barriers. Our aim was to assess the effectiveness of interventions to overcome barriers to patient participation in randomised controlled trials (RCTs) of cancer treatments.

Methods

A systematic review was conducted. Published and unpublished studies in any language were searched for in fifteen electronic databases, including MEDLINE, EMBASE, CINAHL and PsycINFO, from inception to the end of 2004. Studies of any interventions to improve cancer patient participation in RCTs, which reported the change in recruitment rates, were eligible for inclusion. RCTs and non-randomised controlled trials as well as before and after studies reporting baseline rates specific to the population being investigated were included. Data were extracted by one reviewer into structured summary tables and checked for accuracy by a second reviewer. Each included study was assessed against a checklist for methodological quality by one reviewer and checked by a second reviewer. A narrative synthesis was conducted.

Results

Eight studies were identified that met the inclusion criteria: three RCTs, two non-randomised controlled trials and three observational studies. Six of the studies had an intervention that had some relevance to the UK. There was no robust evidence that any of the interventions investigated led to an increase in cancer patient participation in RCTs, though one good quality RCT found that urologists and nurses were equally effective at recruiting participants to a treatment trial for prostate cancer. Although there was no evidence of an effect in any of the studies, the evidence was not of sufficient quality to be able to conclude that these interventions therefore do not work.

Conclusion

There is not a strong evidence-base for interventions that increase cancer patient participation in randomised trials. Further research is required to evaluate the effectiveness of strategies to increase participation in cancer treatment trials.  相似文献   

2.
The aim of this research was to screen plant growth biostimulant properties of supercritical CO2 macroalgal extracts. To this end secondary metabolites were isolated from the biomass of marine macroalgae from the Baltic Sea (species of Polysiphonia, Ulva and Cladophora). Chemical characteristics of the algal extracts were determined by inductively coupled plasma atomic emission spectroscopy for inorganic constituents and high-performance liquid chromatography and spectrophotometry for organic constituents. Inorganic (macro- and microelements) and organic (plant hormones: auxins and cytokinins; polyphenols) compounds were detected in the extract. Algal extracts were tested primarily on garden cress (Lepidium sativum L.; Brassicaceae) and wheat (Triticum aestivum L.; Poaceae). The extracts enhanced chlorophyll and carotenoid content in plant shoots, as well as root thickness and above-ground biomass. The most effective method of application of the extract was by foliar feed on cress and seed maceration for wheat. Algal extracts obtained by supercritical fluid extraction (SFE) were found to be a novel natural source of compounds, stimulating growth of cultivated plants. However, field trials will be required to show that the extracts can act as plant biopesticides and growth biostimulants.  相似文献   

3.
Accumulating evidence suggests that inflammation has a key role in the pathogenesis of osteoarthritis (OA). Nitric oxide (NO) has been established as one of the major inflammatory mediators in OA and drives many pathological changes during the development and progression of OA. Excessive production of NO in chondrocytes promotes cartilage destruction and cellular injury. The synthesis of NO in chondrocytes is catalyzed by inducible NO synthase (iNOS), which is thereby an attractive therapeutic target for the treatment of OA. A number of direct and indirect iNOS inhibitors, bioactive compounds, and plant-derived small molecules have been shown to exhibit chondroprotective effects by suppressing the expression of iNOS. Many of these iNOS inhibitors hold promise for the development of new, disease-modifying therapies for OA; however, attempts to demonstrate their success in clinical trials are not yet successful. Many plant extracts and plant-derived small molecules have also shown promise in animal models of OA, though further studies are needed in human clinical trials to confirm their therapeutic potential. In this review, we discuss the role of iNOS in OA pathology and the effects of various iNOS inhibitors in OA.  相似文献   

4.
Glucosamine in its acetylated form is a natural constituent of some glycosaminoglycans (for example, hyaluronic acid and keratan sulfate) in the proteoglycans found in articular cartilage, intervertebral disc and synovial fluid. Glucosamine can be extracted and stabilized by chemical modification and used as a drug or a nutraceutical. It has been approved for the treatment of osteoarthritis (OA) in Europe to promote cartilage and joint health and is sold over the counter as a dietary supplement in the United States. Various formulations of glucosamine have been tested, including glucosamine sulfate and glucosamine hydrochloride. In vitro and in vivo studies have uncovered glucosamine's mechanisms of action on articular tissues (cartilage, synovial membrane and subchondral bone) and justified its efficacy by demonstrating structure-modifying and anti-inflammatory effects at high concentrations. However, results from clinical trials have raised many concerns. Pharmacokinetic studies have shown that glucosamine is easily absorbed, but the current treatment doses (for example, 1,500 mg/day) barely reach the required therapeutic concentration in plasma and tissue. The symptomatic effect size of glucosamine varies greatly depending on the formulation used and the quality of clinical trials. Importantly, the effect size reduces when evidence is accumulated chronologically and evidence for the structure-modifying effects of glucosamine are sparse. Hence, glucosamine was at first recommended by EULAR and OARSI for the management of knee pain and structure improvement in OA patients, but not in the most recent NICE guidelines. Consequently, the published recommendations for the management of OA require revision. Glucosamine is generally safe and although there are concerns about potential allergic and salt-related side effects of some formulations, no major adverse events have been reported so far. This paper examines all the in vitro and in vivo evidence for the mechanism of action of glucosamine as well as reviews the results of clinical trials. The pharmacokinetics, side effects and differences observed with different formulations of glucosamine and combination therapies are also considered. Finally, the importance of study design and criteria of evaluation are highlighted as new compounds represent new interesting options for the management of OA.  相似文献   

5.
There is mounting evidence silicon (Si) can alter plant nutrient dynamics and is an important functional trait in plant defence and plant–insect ecology. Despite this, there remains a paucity in our understanding of how Si‐driven changes in nutritional quality can impact herbivore performance across different plant species. We investigated how Si alters plant nutritional quality and the concomitant effects on the performance of the Australian native generalist herbivore Helicoverpa punctigera feeding on three economically significant plant species of varying Si‐uptake ability: Brassica napus (non‐Si accumulator), Cucumis sativus (intermediate Si accumulator) and Sorghum bicolor (high Si accumulator). Si supplementation reduced the nutritional quality of B. napus but increased phosphorus concentrations in S. bicolor. Si reduced herbivore performance in all host–plant species, which correlated directly with Si concentrations in Si‐accumulating host plants C. sativus and S. bicolor. However, on B. napus, Si affected herbivore performance indirectly by reducing nutritional quality (foliar carbon:nitrogen ratio and phosphorus concentration). This suggests Si availability can affect herbivore performance directly via Si concentration on Si‐accumulating hosts, and indirectly via nutritional quality in a non‐Si accumulator. The resistance‐enhancing effects of Si on multiple species offer opportunity for agriculture to utilise this abundant element in sustainable management practices.  相似文献   

6.
Six different crude extracts from bark powder of an important medicinal plant, Acacia nilotica (L.) were investigated for their toxicity against Spodoptera litura (Fab.). Total phenolic content in six crude extracts was measured. Ultra-High Performance Liquid Chromatography (UHPLC) was also performed for qualitative analysis of six crude extracts which revealed the presence of 11 phenolic compounds. Bioassays conducted with all crude extracts revealed maximum adverse effect with acetone extract. Duration of larval period and total development period was found to be prolonged. Various aberrations were observed in pupae and adults in the form of wrinkled pupae, blackened pupae, bulged out head part of pupae, partially emerged adults and adults with crumpled wings. All nutritional indices viz. RGR, RCR, ECI, ECD and AD decreased with treatment. The findings indicated that A. nilotica had considerable potential in the management of this serious insect pest.  相似文献   

7.
BackgroundHospitals, clinics, and health organizations have provided psychosocial support interventions for medical patients to supplement curative care. Prior reviews of interventions augmenting psychosocial support in medical settings have reported mixed outcomes. This meta-analysis addresses the questions of how effective are psychosocial support interventions in improving patient survival and which potential moderating features are associated with greater effectiveness.Methods and findingsWe evaluated randomized controlled trials (RCTs) of psychosocial support interventions in inpatient and outpatient healthcare settings reporting survival data, including studies reporting disease-related or all-cause mortality. Literature searches included studies reported January 1980 through October 2020 accessed from Embase, Medline, Cochrane Library, CINAHL, Alt HealthWatch, PsycINFO, Social Work Abstracts, and Google Scholar databases. At least 2 reviewers screened studies, extracted data, and assessed study quality, with at least 2 independent reviewers also extracting data and assessing study quality. Odds ratio (OR) and hazard ratio (HR) data were analyzed separately using random effects weighted models. Of 42,054 studies searched, 106 RCTs including 40,280 patients met inclusion criteria. Patient average age was 57.2 years, with 52% females and 48% males; 42% had cardiovascular disease (CVD), 36% had cancer, and 22% had other conditions. Across 87 RCTs reporting data for discrete time periods, the average was OR = 1.20 (95% CI = 1.09 to 1.31, p < 0.001), indicating a 20% increased likelihood of survival among patients receiving psychosocial support compared to control groups receiving standard medical care. Among those studies, psychosocial interventions explicitly promoting health behaviors yielded improved likelihood of survival, whereas interventions without that primary focus did not. Across 22 RCTs reporting survival time, the average was HR = 1.29 (95% CI = 1.12 to 1.49, p < 0.001), indicating a 29% increased probability of survival over time among intervention recipients compared to controls. Among those studies, meta-regressions identified 3 moderating variables: control group type, patient disease severity, and risk of research bias. Studies in which control groups received health information/classes in addition to treatment as usual (TAU) averaged weaker effects than those in which control groups received only TAU. Studies with patients having relatively greater disease severity tended to yield smaller gains in survival time relative to control groups. In one of 3 analyses, studies with higher risk of research bias tended to report better outcomes. The main limitation of the data is that interventions very rarely blinded personnel and participants to study arm, such that expectations for improvement were not controlled.ConclusionsIn this meta-analysis, OR data indicated that psychosocial behavioral support interventions promoting patient motivation/coping to engage in health behaviors improved patient survival, but interventions focusing primarily on patients’ social or emotional outcomes did not prolong life. HR data indicated that psychosocial interventions, predominantly focused on social or emotional outcomes, improved survival but yielded similar effects to health information/classes and were less effective among patients with apparently greater disease severity. Risk of research bias remains a plausible threat to data interpretation.

In a meta-analysis, Timothy Smith and colleagues study trials of the effectiveness of psychosocial support interventions for improving inpatient and outpatient survival.  相似文献   

8.
IntroductionThe rise in gestational diabetes (GDM), defined as first onset or diagnosis of diabetes in pregnancy, is a global problem. GDM is often associated with unhealthy diet and is a major contributor to adverse outcomes maternal and fetal outcomes. Manipulation of nutrition has the potential to prevent GDM.MethodsWe assessed the effects of nutritional manipulation in pregnancy on GDM and relevant maternal and fetal outcomes by a systematic review of the literature. We searched MEDLINE, EMBASE, and Cochrane Database from inception to March 2014 without any language restrictions. Randomised controlled trials (RCT) of nutritional manipulation to prevent GDM were included. We summarised dichotomous data as relative risk (RR) and continuous data as standardised mean difference (SMD) with 95% confidence interval (CI).ResultsFrom 1761 citations, 20 RCTs (6,444 women) met the inclusion criteria. We identified the following interventions: diet-based (n = 6), mixed approach (diet and lifestyle) interventions (n = 13), and nutritional supplements (myo-inositol n = 1, diet with probiotics n = 1). Diet based interventions reduced the risk of GDM by 33% (RR 0.67; 95% CI 0.39, 1.15). Mixed approach interventions based on diet and lifestyle had no effect on GDM (RR 0.95; 95% CI 0.89, 1.22). Nutritional supplements probiotics combined with diet (RR 0.40; 95% CI 0.20, 0.78) and myo-inositol (RR 0.40; 95% CI 0.16, 0.99) were assessed in one trial each and showed a beneficial effect. We observed a significant interaction between the groups based on BMI for diet-based intervention. The risk of GDM was reduced in obese and overweight pregnant women for GDM (RR 0.40, 95% CI 0.18, 0.86).ConclusionsNutritional manipulation in pregnancy based on diet or mixed approach do not appear to reduce the risk of GDM. Nutritional supplements show potential as agents for primary prevention of GDM.  相似文献   

9.

Introduction

To effectively address HIV/AIDS in Africa, evidence on preventing new infections and providing effective treatment is needed. Ideally, decisions on which interventions are effective should be based on evidence from randomized controlled trials (RCTs). Our previous research described African RCTs of HIV/AIDS reported between 1987 and 2003. This study updates that analysis with RCTs published between 2004 and 2008.

Objectives

To describe RCTs of HIV/AIDS conducted in Africa and reported between 2004 and 2008.

Methods

We searched the Cochrane HIV/AIDS Specialized Register in September 2009. Two researchers independently evaluated studies for inclusion and extracted data using standardized forms. Details included location of trials, interventions, methodological quality, location of principal investigators and funders.

Results

Our search identified 834 RCTs, with 68 conducted in Africa. Forty-three assessed prevention-interventions and 25 treatment-interventions. Fifteen of the 43 prevention RCTs focused on preventing mother-to-child HIV transmission. Thirteen of the 25 treatment trials focused on opportunistic infections. Trials were conducted in 16 countries with most in South Africa (20), Zambia (12) and Zimbabwe (9). The median sample size was 628 (range 33-9645). Methods used for the generation of the allocation sequence and allocation concealment were adequate in 38 and 32 trials, respectively, and 58 reports included a CONSORT recommended flow diagram. Twenty-nine principal investigators resided in the United States of America (USA) and 18 were from African countries. Trials were co-funded by different agencies with most of the funding obtained from USA governmental and non-governmental agencies. Nineteen pharmaceutical companies provided partial funding to 15 RCTs and African agencies co-funded 17 RCTs. Ethical approval was reported in 65 trials and informed consent in 61 trials.

Conclusion

Prevention trials dominate the trial landscape in Africa. Of note, few principal investigators and funders are from Africa. These findings mirror our previous work and continue to indicate a need for strengthening trial research capacity in Africa.  相似文献   

10.
Abstract

Considerable interest has been shown in natural sources and their compounds in developing new therapeutically agents for different diseases. In this framework, investigations performed on this topic play a central role for human health and drug development process. Schisandra chinensis (Turcz.) Baill is a medicinal and edible plant showing highly advantageous bioactivity and nutritional value. The main bioactive compounds from its fruits are lignans, derivatives of dibenzocyclooctadiene whereas concerning its leaves, phenolic acids, and flavonoids are dominant. The purpose of this study was to investigate the enzyme inhibitory potential on selected carbohydrate hydrolases, cholinesterases, and tyrosinase of extracts from fruits and leaves of Schisandra in relation with their main bioactive compounds. Furthermore, the interactions between dominant compounds (schisandrol A, schisandrol B, schisandrin B, and cinnamic acid) from extracts and selected enzymes were investigated by molecular modeling and molecular dynamic studies in order to explain at a molecular level our findings.  相似文献   

11.

Objective

This systematic review was performed to summarise randomised clinical trials (RCTs) assessing the efficacy and safety of ginseng in the Korean literature.

Method

The study involved systematic searches conducted in eight Korean Medical databases. The methodological quality of all of the included studies was assessed using the Cochrane Risk of Bias tool. We included all RCTs on any type of ginseng compared to placebo, active treatment or no treatment in healthy individuals or patients regardless of conditions.

Results

In total, 1415 potentially relevant studies were identified, and 30 randomised clinical trials were included. Nine RCTs assessed the effects of ginseng on exercise capacity, cognitive performance, somatic symptoms, quality of life, and sleeping in healthy persons. Six RCTs tested ginseng compared with placebo for erectile dysfunction, while another four studies evaluated the effects of ginseng against no treatment for gastric and colon cancer. Two RCTs compared the effect of red ginseng on diabetes mellitus with no treatment or placebo, and the other nine RCTs assessed the effects of ginseng compared with placebo or no treatment on various conditions. The methodological caveats of the included trials make their contribution to the current clinical evidence of ginseng somewhat limited. However, the 20 newly added trials (66.7% of the 30 trials) may provide useful information for future trials. Ginseng appears to be generally safe, and no serious adverse effects have been reported.

Conclusions

The clinical effects of ginseng have been tested in a wide range of conditions in Korea. Although the quality of RCTs published in the Korean literature was generally poor, this review is useful for researchers to access studies that were originally published in languages that they would otherwise be unable to read and due to the paucity of evidence on this subject.  相似文献   

12.
Many diets and nutritional advice are circulating, often based on short‐ or medium‐term clinical trials and primary outcomes, like changes in LDL cholesterol or weight. It remains difficult to assess which dietary interventions can be effective in the long term to reduce the risk of aging‐related disease and increase the (healthy) lifespan. At the same time, the scientific discipline that studies the aging process has identified some important nutrient‐sensing pathways that modulate the aging process, such as the mTOR and the insulin/insulin‐like growth factor signaling pathway. A thorough understanding of the aging process can help assessing the efficacy of dietary interventions aimed at reducing the risk of aging‐related diseases. To come to these insights, a synthesis of biogerontological, nutritional, and medical knowledge is needed, which can be framed in a new discipline called ‘nutrigerontology’.  相似文献   

13.
Considering the important role of oxidative stress in the pathogenesis of several neurological diseases, and the growing evidence of the presence of compounds with antioxidant properties in the plant extracts, the aim of the present study was to investigate the antioxidant capacity of three plants used in Brazil to treat neurological disorders: Melissa officinalis, Matricaria recutita and Cymbopogon citratus. The antioxidant effect of phenolic compounds commonly found in plant extracts, namely, quercetin, gallic acid, quercitrin and rutin was also examined for comparative purposes. Cerebral lipid peroxidation (assessed by TBARS) was induced by iron sulfate (10 μM), sodium nitroprusside (5 μM) or 3-nitropropionic acid (2 mM). Free radical scavenger properties and the chemical composition of plant extracts were assessed by 1′-1′ Diphenyl-2′ picrylhydrazyl (DPPH) method and by Thin Layer Chromatography (TLC), respectively. M. officinalis aqueous extract caused the highest decrease in TBARS production induced by all tested pro-oxidants. In the DPPH assay, M. officinalis presented also the best antioxidant effect, but, in this case, the antioxidant potencies were similar for the aqueous, methanolic and ethanolic extracts. Among the purified compounds, quercetin had the highest antioxidant activity followed by gallic acid, quercitrin and rutin. In this work, we have demonstrated that the plant extracts could protect against oxidative damage induced by various pro-oxidant agents that induce lipid peroxidation by different process. Thus, plant extracts could inhibit the generation of early chemical reactive species that subsequently initiate lipid peroxidation or, alternatively, they could block a common final pathway in the process of polyunsaturated fatty acids peroxidation. Our study indicates that M. officinalis could be considered an effective agent in the prevention of various neurological diseases associated with oxidative stress.  相似文献   

14.
Fungal secondary compounds and total extracts are known to affect growth of bacteria, fungi, and plants. This study tested the effects of purified compounds and total extracts from three lichens on the growth of two plant pathogens, Ophiostoma novo-ulmi ssp. americana and Sclerotinia sclerotiorum. Usnic acid showed no reduction in relative growth rates (RGR), whereas vulpinic acid reduced RGR for both fungi and atranorin reduced RGR of S. sclerotiorum only. However, purified vulpinic acid showed stronger effects than total extracts on fungal growth. The results suggest that these lichens show further promise as a source for bioactive compounds against fungi.  相似文献   

15.
16.
Toddalia asiatica (L.) Lam. is extensively used in traditional medicinal systems by various cultures. Despite its frequent use in traditional medicine, there is still a paucity of scientific information on T. asiatica growing on the tropical island of Mauritius. Therefore, the present study was designed to appraise the pharmacological and phytochemical profile of extracts (methanol, ethyl acetate and water) and essential oil obtained from aerial parts of T. asiatica. Biological investigation involved the evaluation of in vitro antioxidant and enzyme inhibitory potentials. The chemical profile of the EO was determined using gas chromatography coupled to mass spectrometry (GC/MS) analysis, while for the extracts, the total phenolic (TPC) and flavonoid content were quantified as well as their individual phenolic compounds by LC/MS/MS. Quinic acid, fumaric acid, chlorogenic acid, quercitrin and isoquercitrin were the main compounds in the extracts. Highest total phenolic (82.5±0.94 mg gallic acid equivalent (GAE/g)) and flavonoid (43.8±0.31 mg rutin equivalent (RE/g)) content were observed for the methanol extract. The GC/MS analysis has shown the presence of 26 compounds with linalool (30.9 %), linalyl acetate (20.9 %) and β-phellandrene (7.9 %) being most abundant components in the EO. The extracts and EO showed notable antioxidant properties, with the methanol extract proved to be superior source of antioxidant compounds. Noteworthy anti-acetylcholinesterase (AChE) and anti-butyrylcholinesterase (BChE) effects were recorded for the tested samples, while only the methanol and ethyl acetate extracts were active against tyrosinase. With respect to antidiabetic effects, the extracts and EO were potent inhibitors of α-glucosidase, while modest activity was recorded against α-amylase. Docking results showed that linalyl acetate has the highest affinity to interact with the active site of BChE with docking score of −6.25 kcal/mol. The findings amassed herein act as a stimulus for further investigations of this plant as a potential source of bioactive compounds which can be exploited as phyto-therapeutics.  相似文献   

17.
One prediction of the novel weapons hypothesis (NWH) for the dominance of exotic invasive plant species is that the allelopathic effects of successful invaders will, in general, be more biochemically inhibitory to native species and microbes in invaded regions than the native plants themselves. However, no study has compared biochemical concentrations, compositions, or effects of large numbers of native species to those of large numbers of invasive species. In this context we tested the allelopathic and antimicrobial potentials of nine native plant species and nine invasive species in East Asia by comparing their broad phenolic contents and the effects of extracts made from each of the species on target plants and soil fungi. Three of the invasive species, including Eupatorium rugosum, had higher concentrations of total phenolic compounds than any of the native species, and the mean concentration of total phenolics for invasive species was 2.6 times greater than the mean for native species. Only scopoletin was novel to the invasive species, being found in all of nine invasive species, but not in the native species. More importantly, the effects of the total suites of phenolic compounds produced by invasive species differed from the effects of phenolics produced by natives. Extracts of invasive species reduced radicle growth of the three test plant species by 60–80%, but extracts of native species reduced radicle growth by only 30–50%. Extracts of invasive species reduced shoot growth of the three test species by 20–40%, but the overall effect of native species’ extract was to stimulate shoot growth. The antimicrobial activity of invasive species was also significantly higher than that of native species. It should be noted that phenolics are just one component of a plant’s potential allelopathic arsenal and non-phenolic compounds are likely to play a role in the total extract effect. For example, extracts of P. americana contained the lowest levels of phenolic compounds, but exhibited the strongest inhibition effect. We could not determine whether the greater inhibitory effects of the extracts from invasive species were due to novel combinations of chemicals or higher concentrations of chemicals, but our results are consistent with the predictions of the NWH.  相似文献   

18.

Background

Chronic pain has been estimated to affect 60% of patients with diabetes and is strongly associated with reduced activity tolerance. We systematically reviewed randomized controlled trials (RCTs) that explored interventions to improve physical activity among patients with diabetes to establish whether co-morbid chronic pain was captured at baseline or explored as an effect modifier and if trials reported a component designed to target chronic pain.

Methodology/principal Findings

We searched CINAHL, Cochrane Central Registry of Controlled Trials, EMBASE, ERIC, MEDLINE, SPORTDiscus and PsycInfo from inception of each database to March 2012 for RCTs that enrolled patients with diabetes and randomly assigned them to an intervention designed to promote physical activity. Two reviewers independently selected trials and abstracted data. We identified 136 trials meeting our inclusion criteria, only one of which that reported capturing chronic pain measures at baseline. No trial reported on specific interventions to address chronic pain as a competing demand, or as an effect modifier.

Conclusion/significance

Only 1 trial identified that aimed to promote physical activity among patients with diabetes reported that co-morbid chronic pain was captured at baseline. No trials reported exploring chronic pain as an effect modifier or targeting it as part of its intervention.  相似文献   

19.
Temperature can regulate a number of important biological processes and species interactions. For example, environmental temperature can alter insect herbivore consumption, growth and survivorship, suggesting that temperature‐driven impacts on herbivory could influence plant community composition or nutrient cycling. However, few studies to date have examined whether rising temperature influences herbivore preference and performance among multiple plant species, which often dictates their impact at the community level. Here, we assessed the effects of temperature on the performance and preference of the generalist herbivore Popillia japonica among nine plant species. We show that, on average, consumption rates and herbivore performance increased at higher temperatures. However, there was considerable variation among plant species with consumption and performance increasing on some plant species at higher temperatures but decreasing on others. Plant nutritional quality appeared to influence these patterns as beetles increased feeding on high‐nitrogen plants with increasing temperature, suggesting stronger nitrogen limitation. In addition to changes in feeding rates, feeding preferences of P. japonica shifted among temperatures, a pattern that was largely explained by differential deterrence of plant chemical extracts at different temperatures. In fact, temperature‐induced changes in the efficacy of plant chemical extracts led P. japonica to reduce its diet breadth at higher temperatures. Our results indicate that rising temperatures will influence herbivore feeding behavior by altering the importance of plant nutritional and chemical traits, suggesting that climate change will alter the strength and sign of plant–insect interactions.  相似文献   

20.
The current guidelines of evidence-based medicine (EBM) presuppose that clinical research and clinical practice should advance from rigorous scientific tests as they generate reliable, value-free knowledge. Under this presupposition, hypotheses postulated by doctors and patients in the process of their decision making are preferably tested in randomized clinical trials (RCTs), and in systematic reviews and meta-analyses summarizing outcomes from multiple RCTs. Since testing under this scheme is predominantly focused on the criteria of generality and precision achieved through methodological rigor, at the cost of the criterion of realism, translating test results to clinical practice is often problematic. Choices concerning which methodological criteria should have priority are inevitable, however, as clinical trials, and scientific research in general, cannot meet all relevant criteria at the same time. Since these choices may be informed by considerations external to science, we must acknowledge that science cannot be value-free in a strict sense, and this invites a more prominent role for value-laden considerations in evaluating clinical research. The urgency for this becomes even more apparent when we consider the important yet implicit role of scientific theories in EBM, which may also be subjected to methodological evaluation and for which selectiveness in methodological focus is likewise inevitable.  相似文献   

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