128 research outputs found

    Building block libraries and structural considerations in the self-assembly of polyoxometalate and polyoxothiometalate systems

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    Inorganic metal-oxide clusters form a class of compounds that are unique in their topological and electronic versatility and are becoming increasingly more important in a variety of applications. Namely, Polyoxometalates (POMs) have shown an unmatched range of physical properties and the ability to form structures that can bridge several length scales. The formation of these molecular clusters is often ambiguous and is governed by self-assembly processes that limit our ability to rationally design such molecules. However, recent years have shown that by considering new building block principles the design and discovery of novel complex clusters is aiding our understanding of this process. Now with current progress in thiometalate chemistry, specifically polyoxothiometalates (POTM), the field of inorganic molecular clusters has further diversified allowing for the targeted development of molecules with specific functionality. This chapter discusses the main differences between POM and POTM systems and how this affects synthetic methodologies and reactivities. We will illustrate how careful structural considerations can lead to the generation of novel building blocks and further deepen our understanding of complex systems

    After-hours colorectal surgery: a risk factor for anastomotic leakage

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    __Purpose:__ This study aims to increase knowledge of colorectal anastomotic leakage by performing an incidence study and risk factor analysis with new potential risk factors in a Dutch tertiary referral center. __Methods:__ All patients whom received a primary colorectal anastomosis between 1997 and 2007 were selected by means of operation codes. Patient records were studied for population description and risk factor analysis. __Results:__ In total 739 patients were included. Anastomotic leakage (AL) occurred in 64 (8.7%) patients of whom nine (14.1%) died. Median interval between operation and diagnosis was 8 days. The risk for AL was higher as the anastomoses were constructed more distally (p = 0.019). Univariate analysis showed duration of surgery (p = 0.038), BMI (p = 0.001), time of surgery (p = 0.029), prophylactic drainage (p = 0.006) and time under anesthesia (p = 0.012) to be associated to AL. Multivariate analysis showed BMI greater than 30 kg/m2(p = 0.006; OR 2.6 CI 1.3-5.2) and "after hours" construction of an anastomosis (p = 0.030; OR 2.2 CI 1.1-4.5) to be independent risk factors. __Conclusion:__ BMI greater than 30 kg/m2and "after hours" construction of an anastomosis were independent risk factors for colorectal anastomotic leakage

    Prognostic Factors in 77 Curative Chest Wall Resections for Isolated Breast Cancer Recurrence

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    Background: Full-thickness chest wall resection (CWR) is the preferred treatment for breast cancer (BC) patients with extensive isolated locoregional recurrence. It remains a challenge to select patients that will benefit most from this treatment. The aim of this study was to define prognostic factors in patients who undergo CWR with curative intent. Methods: BC patients who underwent a CWR with curative intent for recurrence of disease between 1986 and 2006 were included in this retrospective study. Twenty-two factors were studied in a univariate analyses, and multivariate stepwise Cox regression analyses was performed. Results: Seventy-seven patients were included in this study. The 5-year overall survival was 25%. There was one postoperative death. Univariate analyses showed that three prognostic factors were significantly correlated with OS and disease-free survival: (1) interval between primary treatment and CWR (P = .02 and .004, respectively), (2) chemotherapy for recurrence (P = .05 and .05, respectively), and (3) resection specimen smaller than 150 cm2(P = .03 and .009, respectively). An interval lasting >10 years between primary treatment and CWR remained statistically significantly correlated with better overall survival and disease-free survival after multivariate analyses. Conclusions: CWR is a safe treatment in patients who have isolated extensive BC recurrence. The best survival outcome was seen in patients after a disease-free interval of >10 years. Existing data show that adjuvant radiotherapy and adjuvant hormone therapy for estrogen-positive tumors improves overall survival. Neoadjuvant chemotherapy may be considered in individual patients

    Twelve-year outcomes of watchful waiting versus surgery of mildly symptomatic or asymptomatic inguinal hernia in men aged 50 years and older:a randomised controlled trial

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    Background: Inguinal hernia belongs to the most common surgical pathology worldwide. Approximately, one third is asymptomatic. The value of watchful waiting (WW) in patients with asymptomatic or mildly symptomatic inguinal hernia has been established in a few randomised controlled trials (RCTs). The aim of this study was to assess long-term outcomes of a RCT comparing WW and elective surgery.Methods: In the original study, men aged ≥50 years with an asymptomatic or mildly symptomatic inguinal hernia were randomly assigned to WW or elective repair. In the present study, the primary outcome was the 12-year crossover rate to surgery, secondary outcomes were time-to-crossover, patient regret, pain, quality of life and incarceration. Dutch Trial Registry: NTR629. Findings: Out of 496 originally analysed patients, 488 (98.4%) were evaluable for chart review (WW: n = 258, surgery: n = 230), and 200 (41.0%) for telephone contact (WW: n = 106, surgery: n = 94) between November 2021 and March 2022 with a median 12 years follow-up (IQR 9–14). After 12 years, the estimated cumulative crossover rate to surgery was 64.2%, which was higher in mildly symptomatic than in asymptomatic patients (71.7% versus 60.4%, HR 1.451, 95% CI: 1.064–1.979). Time-to-crossover was longer in asymptomatic patients (50% after 6.0 years versus 2.0 years, p = 0.019). Patient regret was higher in the WW group (37.7 versus 18.0%, p = 0.002), as well as pain/discomfort (p = 0.031). Quality of life did not differ (p = 0.737). In the WW group, incarceration occurred in 10/255 patients (3.9%). Interpretation: During 12-year follow-up, most WW patients crossed over to surgery, significantly earlier with mildly symptomatic hernia. Considering the relatively low incarceration rate, WW might still be an option in asymptomatic patients with a clear preference and being well-informed about pros and cons.</p

    Twelve-year outcomes of watchful waiting versus surgery of mildly symptomatic or asymptomatic inguinal hernia in men aged 50 years and older:a randomised controlled trial

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    Background: Inguinal hernia belongs to the most common surgical pathology worldwide. Approximately, one third is asymptomatic. The value of watchful waiting (WW) in patients with asymptomatic or mildly symptomatic inguinal hernia has been established in a few randomised controlled trials (RCTs). The aim of this study was to assess long-term outcomes of a RCT comparing WW and elective surgery. Methods: In the original study, men aged ≥50 years with an asymptomatic or mildly symptomatic inguinal hernia were randomly assigned to WW or elective repair. In the present study, the primary outcome was the 12-year crossover rate to surgery, secondary outcomes were time-to-crossover, patient regret, pain, quality of life and incarceration. Dutch Trial Registry: NTR629. Findings: Out of 496 originally analysed patients, 488 (98.4%) were evaluable for chart review (WW: n = 258, surgery: n = 230), and 200 (41.0%) for telephone contact (WW: n = 106, surgery: n = 94) between November 2021 and March 2022 with a median 12 years follow-up (IQR 9–14). After 12 years, the estimated cumulative crossover rate to surgery was 64.2%, which was higher in mildly symptomatic than in asymptomatic patients (71.7% versus 60.4%, HR 1.451, 95% CI: 1.064–1.979). Time-to-crossover was longer in asymptomatic patients (50% after 6.0 years versus 2.0 years, p = 0.019). Patient regret was higher in the WW group (37.7 versus 18.0%, p = 0.002), as well as pain/discomfort (p = 0.031). Quality of life did not differ (p = 0.737). In the WW group, incarceration occurred in 10/255 patients (3.9%). Interpretation: During 12-year follow-up, most WW patients crossed over to surgery, significantly earlier with mildly symptomatic hernia. Considering the relatively low incarceration rate, WW might still be an option in asymptomatic patients with a clear preference and being well-informed about pros and cons. Funding: The initial trial was funded by the Netherlands Organisation for Health Research and Development (ZonMW). This long-term study did not receive funding.</p

    Clinical Trials in Head Injury

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    Traumatic brain injury (TBI) remains a major public health problem globally. In the United States the incidence of closed head injuries admitted to hospitals is conservatively estimated to be 200 per 100,000 population, and the incidence of penetrating head injury is estimated to be 12 per 100,000, the highest of any developed country in the world. This yields an approximate number of 500,000 new cases each year, a sizeable proportion of which demonstrate signficant long-term disabilities. Unfortunately, there is a paucity of proven therapies for this disease. For a variety of reasons, clinical trials for this condition have been difficult to design and perform. Despite promising pre-clinical data, most of the trials that have been performed in recent years have failed to demonstrate any significant improvement in outcomes. The reasons for these failures have not always been apparent and any insights gained were not always shared. It was therefore feared that we were running the risk of repeating our mistakes. Recognizing the importance of TBI, the National Institute of Neurological Disorders and Stroke (NINDS) sponsored a workshop that brought together experts from clinical, research, and pharmaceutical backgrounds. This workshop proved to be very informative and yielded many insights into previous and future TBI trials. This paper is an attempt to summarize the key points made at the workshop. It is hoped that these lessons will enhance the planning and design of future efforts in this important field of research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63185/1/089771502753754037.pd

    Clinical research without consent in adults in the emergency setting: a review of patient and public views

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    <p>Abstract</p> <p>Background</p> <p>In emergency research, obtaining informed consent can be problematic. Research to develop and improve treatments for patients admitted to hospital with life-threatening and debilitating conditions is much needed yet the issue of research without consent (RWC) raises concerns about unethical practices and the loss of individual autonomy. Consistent with the policy and practice turn towards greater patient and public involvement in health care decisions, in the US, Canada and EU, guidelines and legislation implemented to protect patients and facilitate acute research with adults who are unable to give consent have been developed with little involvement of the lay public. This paper reviews research examining public opinion regarding RWC for research in emergency situations, and whether the rules and regulations permitting research of this kind are in accordance with the views of those who ultimately may be the most affected.</p> <p>Methods</p> <p>Seven electronic databases were searched: Medline, Embase, CINAHL, Cochrane Database of Systematic Reviews, Philosopher's Index, Age Info, PsychInfo, Sociological Abstracts and Web of Science. Only those articles pertaining to the views of the public in the US, Canada and EU member states were included. Opinion pieces and those not published in English were excluded.</p> <p>Results</p> <p>Considering the wealth of literature on the perspectives of professionals, there was relatively little information about public attitudes. Twelve studies employing a range of research methods were identified. In five of the six questionnaire surveys around half the sample did <it>not </it>agree generally with RWC, though paradoxically, a higher percentage would <it>personally </it>take part in such a study. Unfortunately most of the studies were not designed to investigate individuals' views in any depth. There also appears to be a level of mistrust of medical research and some patients were more likely to accept an experimental treatment 'outside' of a research protocol.</p> <p>Conclusion</p> <p>There are too few data to evaluate whether the rules and regulations permitting RWC protects – or is acceptable to – the public. However, any attempts to engage the public should take place in the context of findings from further basic research to attend to the apparently paradoxical findings of some of the current surveys.</p
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