Investigations Into Whole Water, Prototropic and Amide Proton Exchange in Lanthanide(III) DOTA-Tetraamide Chelates

Lanthanide(III) chelates of DOTA-tetraamide ligands have been an area of particular interest since the discovery that water exchange kinetics are dramatically affected by the switch from acetate to amide side-chain donors. More recently these chelates have attracted interest as potential PARACEST agents for use in MRI. In this paper we report the results of studies using chemical exchange saturation transfer (CEST) and some more recently reported chelates to re-examine the exchange processes in this class of chelate. We find that the conclusions of Parker and Aime are, for the most part, solid; water exchange is slow and a substantial amount of prototropic exchange occurs in aqueous solution. The extent of prototropic exchange increases as the pH increases above 8, leading to higher relaxivities at high pH. However, amide protons are found to contribute only a small amount to the relaxivity at high pH

Heavy metal concentration in the surface sediment of Tanjung Lumpur mangrove forest, Kuantan, Pahang, Malaysia

Surface sediment samples from 2 transects (20 sampling points) of Tanjung Lumpur mangrove forest were analyzed for the concentrations of Pb, Cu, Co and Mn. In this study, the average concentrations of Pb, Cu, Co and Mn were 44.41 μg/g dry weight, 32.79 μg/g dry weight, 5.79 μg/g dry weight and 117.73 μg/g dry weight, respectively. The calculated enrichment factors (EF) obtained for Co and Mn can be considered to have the terigeneous in sources while Pb and Cu are considered to have anthropogenic input

Outcomes of obstructed abdominal wall hernia: results from the UK national small bowel obstruction audit

Background: Abdominal wall hernia is a common surgical condition. Patients may present in an emergency with bowel obstruction, incarceration or strangulation. Small bowel obstruction (SBO) is a serious surgical condition associated with significant morbidity. The aim of this study was to describe current management and outcomes of patients with obstructed hernia in the UK as identified in the National Audit of Small Bowel Obstruction (NASBO). Methods: NASBO collated data on adults treated for SBO at 131 UK hospitals between January and March 2017. Those with obstruction due to abdominal wall hernia were included in this study. Demographics, co-morbidity, imaging, operative treatment, and in-hospital outcomes were recorded. Modelling for factors associated with mortality and complications was undertaken using Cox proportional hazards and multivariable regression modelling. Results: NASBO included 2341 patients, of whom 415 (17·7 per cent) had SBO due to hernia. Surgery was performed in 312 (75·2 per cent) of the 415 patients; small bowel resection was required in 198 (63·5 per cent) of these operations. Non-operative management was reported in 35 (54 per cent) of 65 patients with a parastomal hernia and in 34 (32·1 per cent) of 106 patients with an incisional hernia. The in-hospital mortality rate was 9·4 per cent (39 of 415), and was highest in patients with a groin hernia (11·1 per cent, 17 of 153). Complications were common, including lower respiratory tract infection in 16·3 per cent of patients with a groin hernia. Increased age was associated with an increased risk of death (hazard ratio 1·05, 95 per cent c.i. 1·01 to 1·10; P = 0·009) and complications (odds ratio 1·05, 95 per cent c.i. 1·02 to 1·09; P = 0·001). Conclusion: NASBO has highlighted poor outcomes for patients with SBO due to hernia, highlighting the need for quality improvement initiatives in this group

National prospective cohort study of the burden of acute small bowel obstruction

Background Small bowel obstruction is a common surgical emergency, and is associated with high levels of morbidity and mortality across the world. The literature provides little information on the conservatively managed group. The aim of this study was to describe the burden of small bowel obstruction in the UK. Methods This prospective cohort study was conducted in 131 acute hospitals in the UK between January and April 2017, delivered by trainee research collaboratives. Adult patients with a diagnosis of mechanical small bowel obstruction were included. The primary outcome was in‐hospital mortality. Secondary outcomes included complications, unplanned intensive care admission and readmission within 30 days of discharge. Practice measures, including use of radiological investigations, water soluble contrast, operative and nutritional interventions, were collected. Results Of 2341 patients identified, 693 (29·6 per cent) underwent immediate surgery (within 24 h of admission), 500 (21·4 per cent) had delayed surgery after initial conservative management, and 1148 (49·0 per cent) were managed non‐operatively. The mortality rate was 6·6 per cent (6·4 per cent for non‐operative management, 6·8 per cent for immediate surgery, 6·8 per cent for delayed surgery; P = 0·911). The major complication rate was 14·4 per cent overall, affecting 19·0 per cent in the immediate surgery, 23·6 per cent in the delayed surgery and 7·7 per cent in the non‐operative management groups (P < 0·001). Cox regression found hernia or malignant aetiology and malnutrition to be associated with higher rates of death. Malignant aetiology, operative intervention, acute kidney injury and malnutrition were associated with increased risk of major complication. Conclusion Small bowel obstruction represents a significant healthcare burden. Patient‐level factors such as timing of surgery, acute kidney injury and nutritional status are factors that might be modified to improve outcomes

Outcomes following small bowel obstruction due to malignancy in the national audit of small bowel obstruction

Introduction Patients with cancer who develop small bowel obstruction are at high risk of malnutrition and morbidity following compromise of gastrointestinal tract continuity. This study aimed to characterise current management and outcomes following malignant small bowel obstruction. Methods A prospective, multicentre cohort study of patients with small bowel obstruction who presented to UK hospitals between 16th January and 13th March 2017. Patients who presented with small bowel obstruction due to primary tumours of the intestine (excluding left-sided colonic tumours) or disseminated intra-abdominal malignancy were included. Outcomes included 30-day mortality and in-hospital complications. Cox-proportional hazards models were used to generate adjusted effects estimates, which are presented as hazard ratios (HR) alongside the corresponding 95% confidence interval (95% CI). The threshold for statistical significance was set at the level of P ≤ 0.05 a-priori. Results 205 patients with malignant small bowel obstruction presented to emergency surgery services during the study period. Of these patients, 50 had obstruction due to right sided colon cancer, 143 due to disseminated intraabdominal malignancy, 10 had primary tumours of the small bowel and 2 patients had gastrointestinal stromal tumours. In total 100 out of 205 patients underwent a surgical intervention for obstruction. 30-day in-hospital mortality rate was 11.3% for those with primary tumours and 19.6% for those with disseminated malignancy. Severe risk of malnutrition was an independent predictor for poor mortality in this cohort (adjusted HR 16.18, 95% CI 1.86 to 140.84, p = 0.012). Patients with right-sided colon cancer had high rates of morbidity. Conclusions Mortality rates were high in patients with disseminated malignancy and in those with right sided colon cancer. Further research should identify optimal management strategy to reduce morbidity for these patient groups

Outcomes of obstructed abdominal wall hernia: results from the UK national small bowel obstruction audit

Background Abdominal wall hernia is a common surgical condition. Patients may present in an emergency with bowel obstruction, incarceration or strangulation. Small bowel obstruction (SBO) is a serious surgical condition associated with significant morbidity. The aim of this study was to describe current management and outcomes of patients with obstructed hernia in the UK as identified in the National Audit of Small Bowel Obstruction (NASBO). Methods NASBO collated data on adults treated for SBO at 131 UK hospitals between January and March 2017. Those with obstruction due to abdominal wall hernia were included in this study. Demographics, co‐morbidity, imaging, operative treatment, and in‐hospital outcomes were recorded. Modelling for factors associated with mortality and complications was undertaken using Cox proportional hazards and multivariable regression modelling. Results NASBO included 2341 patients, of whom 415 (17·7 per cent) had SBO due to hernia. Surgery was performed in 312 (75·2 per cent) of the 415 patients; small bowel resection was required in 198 (63·5 per cent) of these operations. Non‐operative management was reported in 35 (54 per cent) of 65 patients with a parastomal hernia and in 34 (32·1 per cent) of 106 patients with an incisional hernia. The in‐hospital mortality rate was 9·4 per cent (39 of 415), and was highest in patients with a groin hernia (11·1 per cent, 17 of 153). Complications were common, including lower respiratory tract infection in 16·3 per cent of patients with a groin hernia. Increased age was associated with an increased risk of death (hazard ratio 1·05, 95 per cent c.i. 1·01 to 1·10; P = 0·009) and complications (odds ratio 1·05, 95 per cent c.i. 1·02 to 1·09; P = 0·001). Conclusion NASBO has highlighted poor outcomes for patients with SBO due to hernia, highlighting the need for quality improvement initiatives in this group

A probabilistic test instrument using sigma-delta phase signal generation technique for mixed signal embedded test

A probabilistic test instrument is proposed for mixed-signal embedded test applications. The system architecture of the instrument and its implementation is presented. The instrument can be used to inject and extract the timing and voltage information associated with signals in high-speed transceiver circuits that are commonly found in data communication applications. Using statistical methods, the probability distributions associated with these signals can be extracted using a simple circuit called a probability extraction unit, consisting of a few simple digital logic gates. At the core of this work is the use of ΣΔ phase-encoding technique to generate both the voltage and timing (phase) references, or strobes used for high-speed sampling. This technique is also used for generating the test stimulant for the device-under-test, or DUT as a shorthand notation. Experimental results reveal the sampling time strobe can be programmed over a phase range of 45 degrees with a phase step of 1 degree at a fixed voltage reference. The DUT stimulant and the timing and voltage references are all programmable in software. This provides additional flexibility and versatility when conducting a test. A prototype of the proposed test instrument was implemented using discrete components assembled on a printed-circuit board and shown to be capable of measuring the output jitter distribution associated with a clock and data signal of a DUT. It was further extended to measure the phase and frequency response of various analog channels associated with the DUT. The performance of the instrument was evaluated by comparing the test results with those obtain using other test techniques, independent of the instrument.Un instrument pour les tests "mixed-signal" basé sur une approche statistique est proposé. L'architecture du système ainsi que son implémentation sont présentés. L'instrument peut être utilisé afin d'injecter ou de capturer des informations en temps et voltage associé aux signaux de hautes fréquences dans les systèmes de communication. En utilisant une approche statistique, la distribution de probabilité associée à un signal peut être calculée à l'aide d'un circuit appelé « probability extraction unit » implémenté de façon digital. De plus, l'utilisation de ΣΔ pour encoder des signaux dans la phase afin de générer des signaux dans le temps ainsi que des références pour du « high speed sampling » est démontré. Les résultats expérimentaux démontrent que des variations de phase de 45 degrés avec des intervalles de1 degré est possible. Ceci permet donc plus de flexibilité pour générer des signaux de tests qui sont programmables. Un prototype de cette technique fut implémenté sur « PCB » afin de démontrer que la technique est fonctionnelle. Les résultats des tests furent également comparés à ceux obtenus avec des instruments de mesures traditionnels et démontrent une excellente corrélation entre la méthode développée et les méthodes existantes

Heavy metal concentration in the surface sediment of Tanjung Lumpur Mangrove Forest, Kuantan, Malaysia

Surface sediment samples from 2 transects (20 sampling points) of Tanjung Lumpur mangrove forest were analyzed for the concentrations of Pb, Cu, Co and Mn. In this study, the average concentrations of Pb, Cu, Co and Mn were 44.41 μg/g dry weight, 32.79 μg/g dry weight, 5.79 μg/g dry weight and 117.73 μg/g dry weight, respectively. The calculated enrichment factors (EF) obtained for Co and Mn can be considered to have the terigeneous in sources while Pb and Cu are considered to have anthropogenic input

Precudiece and dicrimination in higher learning (1995) film

vii, 58 hlm,; ilus,; 25 cm