Design of Abrasion-Resistant, Long-Lasting Antifog Coatings

Fog formation is a common challenge for numerous applications, such as food packaging, mirrors, building windows, and freezer/refrigerator doors. Most notably, fog forms on the inner surfaces of prescription glasses and safety eyewear (particularly when used with a mask), face shields, and helmet lenses. Fogging is caused by the distortion of light from condensed water droplets present on a surface and can typically be prevented if the surface static water contact angle (θ) is less than ∼40°. Such a low contact angle can be readily achieved by either increasing the substrate surface energy or by engineering surface nanotexture. Unfortunately, such nanotexture can be readily damaged with use, while high surface energy substrates get covered with low surface energy foulants over time. Consequently, even with numerous ephemeral antifog coatings, currently there are no commercially available, durable, and permanent antifog coatings. Here we discuss the development of a new class of high-performance antifog coatings that are abrasion-resistant and long-lasting. These polyvinylpyrrolidone-based coatings, designed based on the classical Ratner-Lancaster wear model, dramatically outperform the base polymer, as well as all tested commercially available antifog coatings. Specifically, these coatings exhibit a > 400% increase in fogging time compared to base polymer, a > 50,000% increase in wear resistance, and excellent long-term antifog performance. The developed coatings also significantly outperformed all tested commercially available antifog coatings in terms of their antifog performance, wear resistance, and long-term cyclical performance. Additionally, the key design strategies employed here─incorporation of toughening agents and hydrophilic slip additives─offer a new approach to developing high-performance, durable antifog coatings based on other well-known antifog polymers.

A76 PHYSICIANS PERCEIVED VALUE OF COMPUTED TOMOGRAPHY SCANS FOR INFLAMMATORY BOWEL DISEASE PATIENTS IN THE EMERGENCY DEPARTMENT: A SURVEY OF CANADIAN PHYSICIANS

Background

Despite concerns regarding the risks of ionizing radiation from computed tomography (CT) imaging, the rates of abdominal pelvic CT (APCT) utilization in the emergency department (ED) continues to increase for patients with inflammatory bowel disease (IBD).

Purpose

To determine the factors that drive decisions on when to perform APCT imaging in the ED for patients with IBD and to determine if differences exist between physician specialties.

Method

We performed a quantitative, web-based survey between November 2021 and August 2022. Structured questions for Crohn’s disease (CD) and ulcerative colitis (UC) were developed with input from stakeholders in gastroenterology, surgery, and emergency medicine. Surveys were disseminated to Canadian physicians in each of the three specialities through personal emails, and by newsletter from national specialty organizations. Between specialty comparisons were performed by Chi-squared and Fisher exact tests where appropriate.

Result(s)

A total of 208 participants responded to our survey: median age 44 years (IQR 37-50), 132 (63%) male, and 141 (68%) in an academic practice. Survey participants included 81 (39%) gastroenterologists, 35 (17%) surgeons and 92 (44%) emergency physicians.

There were significant differences between specialties in the perceived rates of positive findings from APCT imaging. In UC, gastroenterologists felt inflammation alone was more common than emergency physicians and bowel obstruction and septic complications less common than surgeons and emergency physicians. In CD, surgeons felt bowel obstructions, septic complications and bowel perforations were more common compared with gastroenterologists and emergency physicians.

There were significant differences between specialties in the types of clinical presentations that drove decisions to arrange APCT imaging (Figure 1a&b). In UC, gastroenterologists were less likely to order APCT imaging for diarrhea with rectal bleeding, abdominal pain without peritoneal findings and fever than surgeons and emergency physicians. In CD, there were similar practice patterns between specialities except gastroenterologists were less likely to order APCT imaging for diarrhea with rectal bleeding than surgeons.

Image

Conclusion(s)

Our survey identified key differences between physician specialties in the perceived rates of positive findings from APCT imaging and practice patterns of CT utilization. These findings will help to guide the development of future multidisciplinary consensus guidelines for the appropriateness of CT imaging in the ED for patients with IBD.

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Disclosure of Interest

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Polysiloxane-Based Liquid-like Layers for Reducing Polymer and Wax Fouling

Surface fouling occurs when undesired matter adheres and accumulates on a surface, resulting in a decrease or loss of functionality. Polymer and wax fouling can cause costly blockages to crude oil pipelines, clog jet fuel injectors, foul chemical reaction vessels, and significantly decrease the efficiency of heat exchangers. Fouling occurs in many forms but can be segmented based on adherent size, modulus, and chemical functionality. Depending on the foulant, surface design strategies can vary greatly. Few strategies exist to prevent the buildup of wax and polymers on surfaces. In this report, we investigate the potential of highly disordered, siloxane liquid-like layers as a strategy for reducing wax and polymer deposition. In our tests, it was found that the liquid-like layers developed here were able to reduce postadsorption roughness for polymer and wax by as much as 35- and 47-fold, respectively, when compared to the control. SFG was utilized to investigate the molecular-level interfacial properties for each of the modified surfaces to help understand the antifouling mechanism. The data showed that the likely higher grafting density and a large degree of random conformational freedom at the liquid-surface interface make the developed siloxane-covered surfaces energetically unfavorable for polymer and wax accretion.

Rapid and Robust Surface Treatment for Simultaneous Solid and Liquid Repellency

A wide range of liquid and solid contaminants can adhere to everyday functional surfaces and dramatically alter their performance. Numerous surface modification strategies have been developed that can reduce the fouling of some solids or repel certain liquids but are generally limited to specific contaminants or class of foulants. This is due to the typically distinct mechanisms that are employed to repel liquids vs solids. Here, we demonstrate a rapid and facile surface modification technique that yields a thin film of linear chain siloxane molecules covalently tethered to a surface. We investigate and characterize the liquid-like morphology of these surfaces in detail as the key contributing factor to their anti-fouling performance. This surface treatment is extremely durable and readily repels a broad range of liquids with varying surface tensions and polarities, including water, oils, organic solvents, and even fluorinated solvents. Additionally, the flexible, liquid-like nature of these surfaces enables interfacial slippage, which dramatically reduces adhesion to various types of solids, including ice, wax, calcined gypsum, and cyanoacrylate adhesives, and also minimizes the nucleation of inorganic scale. The developed surfaces are durable and simple to fabricate, and they minimize fouling by both liquids and solids simultaneously.

Design and applications of surfaces that control the accretion of matter

Surfaces that provide control over liquid, solid, or vapor accretion provide an evolutionary advantage to numerous plants, insects, and animals. Synthetic surfaces inspired by these natural surfaces can have a substantial impact on diverse commercial applications. Engineered liquid and solid repellent surfaces are often designed to impart control over a single state of matter, phase, or fouling length scale. However, surfaces used in diverse real-world applications need to effectively control the accrual of matter across multiple phases and fouling length scales. We discuss the surface design strategies aimed at controlling the accretion of different states of matter, particularly those that work across multiple length scales and different foulants. We also highlight notable applications, as well as challenges associated with these designer surfaces' scale-up and commercialization.

Risk factors for progression of paroxysmal to persistent atrial fibrillation following successful PV isolation

Background

Progression from paroxysmal (PAF) to persistent atrial fibrillation (PerAF) following effective PV isolation (PVI) has important clinical implications, as it is relevant for subsequent management of the arrhythmia.

Objective

We evaluated risk factors responsible for progression of PAF to PerAF following successful PVI.

Methods

Consecutive AF patients that received their first catheter ablation as well as the first redo at our center were identified (n=1352). Patients were included in group 1 if the diagnosis was PAF at both first and redo procedure (PAF to PAF) and group 2 if PAF at index progressed to PerAF at redo. All patients received PVI plus isolation of LA posterior wall and SVC at the first procedure.

Results

A total of 822 patients remained as PAF at redo, whereas 530 (39%) progressed from PAF to PerAF. Clinical characteristics of the study population are presented in table 1. In multivariate analysis, BMI (OR 1.02, 1.01–1.04, p=0.04), hypertension (1.4, 1.08–1.8, p=0.01), heart failure (1.67, 1.03–2.69, p=0.03), LA size (2.75, 2.29–3.31, p<0.001) were independent predictors of progression of PAF to PerAF. Data on serum-transthyretin level was available for 37 and 48 patients in group 1 and 2 respectively. It was <18 mg/dL (normal) in 33 (68.7%) patients in group 2 vs 6 (16.2%) in group 1 (p<0.001).

Conclusion

In our patients, after successful PVI, progression of PAF to PerAF was mediated by independent risk factors such as high BMI, heart failure, hypertension, larger LA size and lower LVEF.

Funding Acknowledgement

Type of funding source: None

Extended Pulmonary Vein Isolation: is it sufficient to achieve long-term sinus rhythm in octogenarian women with atrial fibrillation?

Background

Atrial fibrillation (AF) is a disease of the elderly and women typically present with AF at an older age than men do. Moreover, they tend to experience more symptoms and post-ablation recurrences, have worse quality of life and increased risk of stroke and mortality.

Objective

We evaluated long-term efficacy of our standard ablation approach of extended pulmonary vein isolation (PVI) in octogenarian women undergoing their first AF ablation.

Methods

Consecutive female AF patients aged ≥80 years receiving their first catheter ablation at our center were included in the analysis. Our standard ablation approach at the first procedure includes PVI + empirical isolation of left atrial posterior wall (LAPW) and superior vena cava (SVC). Complete abolition of all potentials rather than decrease in amplitudes was the procedural end point. Patients were prospectively monitored at regular intervals for 3 years after the index procedure with event recorders, 12-lead ECG, cardiology evaluation at office visits and 7-day Holter monitoring.

Results

A total of 194 patients with mean age of 84.2±1.4 years were included in the analysis. Of the 194, 120 (61.8%) had non-paroxysmal AF. All received PVI+ isolation of LAPW and SVC. Acute procedural success was achieved in 100% of cases.

At 3 years of follow-up, 24 (12.4%) patients remained in sinus rhythm; 22 on- and 2 off-antiarrhythmic drugs (AAD). All of the 23 patients had paroxysmal AF as their initial diagnosis.

Of the 170 patients experiencing recurrence, 147 underwent repeat ablation. PV/PW/SVC reconnection was noted in only 6 (4.1%) patients at redo. Triggers originating from non-PV sites were targeted for ablation in all. At 1.5 years after the repeat procedure, 136 (92.5%) patients were in sinus rhythm; 131 off-AAD and 5 patients on-AAD.

Conclusion

Extended PVI including isolation of posterior wall and SVC was not sufficient to maintain long-term sinus rhythm in majority of octogenarian women, regardless of AF type. Moreover, non-PV triggers rather than PV reconnection was the major cause of recurrence in this subset of AF population.

Funding Acknowledgement

Type of funding source: None

Risk factors and effective ablation strategy in patients presenting with left atrial flutter with no previous ablation for atrial fibrillation

Background

A typical left atrial flutter (LAFL) may occur as a proarrhythmic complication of ablation for atrial fibrillation (AF).

Objective

We evaluated the risk factors and the best ablation strategy for LAFL in patients with no prior AF ablation.

Methods

Consecutive patients undergoing first catheter ablation for AFL with no prior procedure for AF were included in this prospective analysis. Based on the ablation strategy, patients were divided into, Group 1: PVI+ Flutter ablation (ablation of re-entry circuits) and Group 2: PVI+ Non-PV trigger ablation (targeting areas of focal activity as triggers). 3-D mapping of the LA was performed during tachycardia to identify the reentrant circuit.

PV isolation was performed in all patients. In group 1, ablation line was chosen to transect the area critical for the circuit (roof and mitral line). In group 2, ectopic beats arising from extra-PV foci detected by isoproterenol challenge were ablated. Off-drug success rate was assessed in all.

Results

A total of 92 and 90 patients were included in group 1 and 2 respectively. Baseline characteristics are provided in table 1. Pre-existent LA scar was detected in 91.3% and 90% of patients in group 1 and 2 respectively.

At 2 years of follow-up, 11/92 (12%) from group 1 and 60/90 (66.7%) from group 2 remained arrhythmia-free off-drugs (p<0.001). In the multivariate analysis, PVI +flutter ablation was detected to be associated with significantly high risk of recurrence [HR: 3.92 (95% CI: 2.52–6.1, p<0.001)]

Conclusion

In this series of patients presenting with LAFL with no earlier AF ablations, pre-existent left atrial scar was detected in majority of cases and PVI+ non-PV trigger ablation provided significantly better success rate than PVI+ flutter ablation.

Funding Acknowledgement

Type of funding source: None

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Design of surfaces for controlling hard and soft fouling

In this review, we present a framework to guide the design of surfaces which are resistant to solid fouling, based on the modulus and length scale of the fouling material. Solid fouling is defined as the undesired attachment of solid contaminants including ice, clathrates, waxes, inorganic scale, polymers, proteins, dust and biological materials. We first provide an overview of the surface design approaches typically applied across the scope of solid fouling and explain how these disparate research efforts can be united to an extent under a single framework. We discuss how the elastic modulus and the operating length scale of a foulant determine its ability or inability to elastically deform surfaces. When surface deformation occurs, minimization of the substrate elastic modulus is critical for the facile de-bonding of a solid contaminant. Foulants with low modulus or small deposition sizes cannot deform an elastic bulk material and instead de-bond more readily from surfaces with chemistries that minimize their interfacial free energy or induce a particular repellant interaction with the foulant. Overall, we review reported surface design strategies for the reduction in solid fouling, and provide perspective regarding how our framework, together with the modulus and length scale of a foulant, can guide future antifouling surface designs. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology'.

Prevalence of pain flashbacks in posttraumatic stress disorder arising from exposure to multiple traumas or childhood traumatization

Background

Flashbacks are a form of multisensory memory that are experienced with a “happening in the present” quality. Pain flashbacks are a re-experiencing of pain felt at the time of a traumatic event. It is unclear how common pain flashbacks are.

Aims

The current study was designed primarily to assess the prevalence of pain flashbacks in a sample of patients with posttraumatic stress disorder (PTSD).

Methods

We assessed the prevalence of pain flashbacks over a period of 2 years in patients (n = 166) referred to a psychological trauma service in the UK. Patients underwent a clinical screen for PTSD and completed a self-report measure of pain flashbacks.

Results

Pain flashbacks were classified as present in 49% of a sample of complex trauma patients meeting criteria for PTSD. Pain flashbacks were positively associated with the extent of pain at the time of trauma.

Conclusions

Pain re-experiencing in PTSD, and its relative absence in nonclinical populations, supports an account of memory in which perceptual details can be re-experienced when memories have been encoded under conditions of extreme stress. It may be possible to conceptualize some cases of unexplained pain as pain flashbacks or of having a trauma origin.

Structure and Function of Basement Membranes

Basement membranes (BMs) are present in every tissue of the human body. All epithelium and endothelium is in direct association with BMs. BMs are a composite of several large glycoproteins and form an organized scaffold to provide structural support to the tissue and also offer functional input to modulate cellular function. While collagen I is the most abundant protein in the human body, type IV collagen is the most abundant protein in BMs. Matrigel is commonly used as surrogate for BMs in many experiments, but this is a tumor-derived BM–like material and does not contain all of the components that natural BMs possess. The structure of BMs and their functional role in tissues are unique and unlike any other class of proteins in the human body. Increasing evidence suggests that BMs are unique signal input devices that likely fine tune cellular function. Additionally, the resulting endothelial and epithelial heterogeneity in human body is a direct contribution of cell-matrix interaction facilitated by the diverse compositions of BMs.

Phylogeographic evidence for two mesic refugia in a biodiversity hotspot

Phylogeographic studies of flora in species-rich south-western Australia point to complex evolutionary histories, reflecting patterns of persistence and resilience to climatic changes during the Pleistocene. We asked whether coastal areas of the mid-west and south, as well as granite outcrops and inland ranges, have acted as major refugia within this region during Pleistocene climatic fluctuations by analysing phylogeographic patterns in the shrub Calothamnus quadrifidus R.Br. (Myrtaceae). We determined variation in chloroplast DNA data for 41 populations across the geographic range. Relationships and major clades were resolved using parsimony and Bayesian analyses. We tested for demographic and spatial expansion of the major clades and estimated clade divergence dates using an uncorrelated, lognormal relaxed clock based on two conservative chloroplast mutation rates. Two distinct phylogeographic clades were identified showing divergence during the Pleistocene, consistent with other phylogeographic studies of south-west Australian flora, emphasising the impact of climatic oscillations in driving divergence in this landscape. The southern clade was more diverse, having higher haplotype diversity and greater genetic structure, while the northern clade showed evidence of fluctuation in population size. Regions of high haplotype diversity with adjacent areas of low diversity observed in each clade indicated the locations of two coastal refugia: one on the south coast and another along the mid-west coast. This is the first evidence for major Pleistocene refugia using chloroplast genetic data in a common, widespread species from this region.

Computational modelling of long bone fractures fixed with locking plates - How can the risk of implant failure be reduced?

BACKGROUND AND PURPOSE

The Locking Compression Plate (LCP) is part of a new plate generation requiring an adapted surgical technique and new thinking about commonly used concepts of internal fixation using plates. Knowledge of the fixation stability provided by these new plates is very limited and clarification is still necessary to determine how the mechanical stability and the risk of implant failure can best be controlled.

METHODS

Upon validation, a finite element model of an LCP attached to a cylinder was developed to simulate and analyse the biomechanics of a transverse long bone fracture fixed with a locking plate. Of special interest were the factors influencing the mechanical conditions at the fracture site, the control of interfragmentary movement and implant failure.

RESULTS

Several factors were shown to influence stability in compression. Increasing translation and/or fracture angle post fixation reduced construct stability. Axial stiffness was also influenced by the working length and plate-bone distance. The fracture gap had no effect on the construct stability when no bone contact occurred during loading. Stress analysis of the LCP demonstrated that the maximum Von Mises stresses were found in the innermost screws at the screw-head junction.

INTERPRETATION

For the clinical use of the LCP as a locked internal fixator in fractures with an interfragmentary gap of 1 mm, at least two to four plate holes near the fracture gap should be omitted to allow fracture motion and bone contact to occur. This will also achieve a larger area of stress distribution on the plate and reduce the likelihood of fatigue failure due to cyclic loading.

The periseptal annulus: An organelle associated with cell division in Gram-negative bacteria

Evidence is presented that the site of cell division in Salmonella typhimurium is flanked by two circumferential zones of cell envelope differentiation, the periseptal annuli, which separate the division site from the remainder of the cell envelope. Each annulus is composed of a continuous structure in which the membranous elements of the cell envelope are closely associated with the murein cytoskeleton. The paired annuli appear early in the division process and the region between them defines a new cellular domain, the periseptal compartment, within which the division septum is formed.

Systematic review of response evaluation in gastrointestinal stromal tumors

e21500

Background: Our purpose was to conduct an evidence-based systematic review of the literature on the accuracy of 18FDG PET - CT(PET) and contrast enhanced computer tomography (CT) in assessment of response to imatinib therapy in advanced gastrointestinal stromal tumor (GIST) Methods: A systematic review of the literature between January 2000 and December 2008 was performed on Medline and EMBASE. Inclusion criteria included prognostic studies or diagnostic studies using CT or PET to determine response to imatinib. Only articles with Level 1B or higher were included. The following variables were extracted: imaging modality (PET, In-line PET/CT, CT), response criteria used EORTC,RECIST criteria, or novel criteria), and the clinical outcome (time-to-treatment failure (TTF), time to progression (TTP), progression free survival (PFS), disease specific survival (DSS), and/or overall survival). The number of responders and non-responders was extracted from the data, and the reported log rank statistics for the Kaplan Meier curves were used to determine the strength of correlation between the responders and the clinical outcomes. Results: Five articles met the strict criteria for Level 1B evidence. Four articles met the inclusion criteria for In-line PET/CT. In these four articles the log rank correlation between In-line PET/CT response criteria described by the EORTC and the outcome measure of TTF ranged between. p=0.002 -0.04, a very high degree of positive correlation. A subset of four articles met the strict methodological inclusion criteria for CT using RECIST criteria. The log rank correlation for RECIST ranged from p=0.100 - 0.74, no significant correlation. Only one of the articles met the criteria for prospectively applying novel CHOI criteria with CT in a validating cohort. The log rank correlation with the TTF was p=0.0002, a very high degree of positive correlation. Conclusions: In-line PET/CT using EORTC criteria accurately predicts the response to imatinib in terms of TTF or PFS across four Level 1B studies. CT using RECIST criteria has a poor correlation with TTF in well designed studies and is not a useful predictor of response; consistently poor across four Level 1B studies. CT using CHOI criteria shows promise in a single Level 1B study

No significant financial relationships to disclose.

Increased Phase Synchronization between Intracranial Pressure and Arterial Blood Pressure during Elevated Intracranial Pressure in Dogs

We applied the concept of "phase synchronization" from nonlinear dynamics to the complex relationship between intracranial pressure (ICP) and arterial blood pressure (ABP) signals. This method is based on multiresolution wavelet transform (MRWT) in which the signals are divided into different frequency bands. We examined ICP and ABP signals from anaesthetized dogs, exploring normal ICP and elevated ICP by 1~3 ml injection of saline into the cerebral ventricles. Phase synchronization analyses show an interesting phenomenon of phase reset from relatively uniform phase distribution to phase clustering around 0° after injection. To further quantitatively measure phase synchronization, phase coherence is used to distinguish the dynamics of normal ICP and elevated ICP by saline injection. Elevated ICP exhibits higher phase coherence than that of normal ICP. The results suggest that the association between ICP and ABP may involve nonlinear mechanisms of regulation. The clinical application of this method is in investigation.

Prenatal diagnosis of horseshoe kidney by measurement of the renal pelvic angle

OBJECTIVE

The aim of this study was to evaluate the usefulness of measurement of the angle between bilateral renal pelves on axial views in the prenatal ultrasonographic diagnosis of horseshoe kidney.

METHODS

We retrospectively measured the renal pelvic angle in 19 fetuses with horseshoe and 20 fetuses with normal kidneys in the second and third trimesters. Renal pelvic angle was defined as the angle between the long axis of the renal pelves on the axial view of the abdomen. We compared the renal pelvic angles of horseshoe and normal kidneys with unpaired t-test. Taking 140 degrees as a cut-off value, we calculated the sensitivity, specificity and accuracy of pelvic angle measurement for the prenatal diagnosis of horseshoe kidney.

RESULTS

The mean pelvic angles in the fetuses with horseshoe kidney were 116 degrees and 110 degrees in the second and third trimester, respectively. In the normal fetuses, the equivalent angles were 172 degrees and 161 degrees. The difference between the two groups was statistically significant (P < 0.01). Using 140 degrees as the discriminating criterion, the sensitivity, specificity and accuracy of renal pelvic angle measurement for the prenatal diagnosis of horseshoe kidney were all 100%. Fifteen of 19 fetuses with horseshoe kidney had no other abnormality. Four (21%) fetuses had severe complex abnormalities which were associated with trisomy 18 in three cases.

CONCLUSION

Observation and measurement of the renal pelvic angle is a simple and useful method in the prenatal diagnosis of the horseshoe kidney.

Phylogeography and divergence in the chloroplast genome of Western Australian Sandalwood (Santalum spicatum)

Western Australian sandalwood (Santalum spicatum) is widespread throughout Western Australia across the semiarid and arid regions. The diversity and phylogeographic patterns within the chloroplast genome of S. spicatum were investigated using restriction fragment length polymorphism analysis of 23 populations. The chloroplast diversity was structured into two main clades that were geographically separated, one centred in the southern (semiarid region) and the other in the northern (arid) region. Fragmentation due to climatic instability was identified as the most likely influence on the differentiation of the lineages. The lineage in the arid region showed a greater level of differentiation than that in the southern region, suggesting a higher level of gene flow or a more recent range expansion of sandalwood in the southern region. The phylogeographic pattern in the chloroplast genome is congruent with that detected in the nuclear genome, which identified different genetic influences between the regions and also suggested a more recent expansion of sandalwood in the southern region.

An open label study to establish dosing recommendations for nabumetone in juvenile rheumatoid arthritis

OBJECTIVE

Once-a-day dosing with nabumetone has been shown to be effective in adults with rheumatoid arthritis. We establish dosing recommendations for nabumetone in children and adolescents with juvenile rheumatoid arthritis (JRA).

METHODS

An open label, multicenter study was conducted in children with JRA aged 2-16 years, weighing > 14 kg, and requiring nonsteroidal antiinflammatory drugs (NSAID) for control of symptoms. NSAID were discontinued one day prior to study initiation to minimize disease flare. Patients received nabumetone 30 mg/kg once daily (as a tablet or a slurry) for 12 weeks. Efficacy assessment evaluations were performed at Weeks 1, 3, 6, and 12, based on the mean change from baseline at the study endpoint for 6 standard rheumatology variables. An overall assessment of efficacy was determined based on the percentage of patients who did not experience a flare, using the 6 rheumatology variables. Since this was an open label study, only descriptive statistics were obtained for efficacy variables. Routine safety assessments were completed for all patients.

RESULTS

In total, 99 patients with JRA were enrolled and 89 completed the study; mean age was 9.2 years. The proportion of nabumetone treated patients with no flare in disease activity during the nabumetone treatment period was 92/99 (93%). Improvement was noted in each efficacy assessment, although statistical evaluations were not performed. The adverse event profile was similar to that reported for nabumetone in adults with RA.

CONCLUSION

Nabumetone 30 mg/kg/day (up to 2000 mg/day) demonstrated a safe profile with no loss of efficacy compared to previous treatment in children with JRA. The dose can be administered by suspending tablets in warm water to create a slurry.

Use of a telemetered dispensing system for controlling nutrient additions to experimental patch reefs in the ENCORE study at One Tree Island, Great Barrier Reef, Australia

A telemetrically controlled system was developed to add nutrients automatically to experimental patch reefs in a remote marine environment. The experiment, called ENCORE, was done in the lagoon of One Tree Island, a remote research station at the southern end of the Great Barrier Reef. Nutrient dispensing units (NDUs), moored adjacent to patch reefs in the lagoon, were telemetrically linked to a base station on the island. The base station, about 3 km away from the furthest NDU, consisted of a dedicated computer, controller and radio transmitter, which relayed coded signals to a radio receiver mounted on each NDU. This activated a solenoid valve to discharge a measured quantity of concentrated nutrient solution from a measuring chamber using compressed air from a SCUBA tank. The solution was discharged through 4-8 PVC outlets into the basins of the patch reefs to allow thorough mixing. The base station interrogated each NDU to find out if the operation had been successful and stored the information on disk to provide a daily log of operations. Nutrient samples taken within the patch reefs demonstrated that calculated initial mean concentrations of 2 micrograms-at PO4-P l-1 and 10 micrograms-at NH4-N l-1 were achieved. The system we have developed can be used in many situations where regular perturbations need to be introduced to aquatic ecosystems. It uses state-of-the-art technology, yet all components are commercially readily available and relatively inexpensive. Detailed specifications and drawings are available from the Great Barrier Reef Marine Park Authority.

Role of Nitrite in Cured Meat Flavor: A Review

Little is known about the mechanism of the reactions leading to formation of cured meat flavor or of the identity of volatile and non-volatile substances responsible for it. This review of the contribution of nitrite to cured meat flavor in products such as ham, bacon and frankfurters includes sensory analyses and studies of the chemical components contributing to cured meat flavor. The antioxidant properties of nitrite in retarding development of warmed-over flavor in cured meats are also discussed.

Reconstruction of the Fresnel-coded gamma camera images by digital computer

An algorithm for the digital reconstruction of the Fresnel-coded gamma camera image consists of the spatial Fourier transform of the hologram after applying a quadratic phase shift. Background subtraction is implemented by use of positive and negative zone plates. Tomographic planes are reconstructed in 27 sec from a single zone-plate shadow image by successively varying a parameter in the reconstruction algorithm on a small computer system.