Density Distribution in Soft Matter Crystals and Quasicrystals.

The density distribution in solids is often represented as a sum of Gaussian peaks (or similar functions) centered on lattice sites or via a Fourier sum. Here, we argue that representing instead the logarithm of the density distribution via a Fourier sum is better. We show that truncating such a representation after only a few terms can be highly accurate for soft matter crystals. For quasicrystals, this sum does not truncate so easily, nonetheless, representing the density profile in this way is still of great use, enabling us to calculate the phase diagram for a three-dimensional quasicrystal-forming system using an accurate nonlocal density functional theory.

Which Wave Numbers Determine the Thermodynamic Stability of Soft Matter Quasicrystals?

For soft matter to form quasicrystals an important ingredient is to have two characteristic length scales in the interparticle interactions. To be more precise, for stable quasicrystals, periodic modulations of the local density distribution with two particular wave numbers should be favored, and the ratio of these wave numbers should be close to certain special values. So, for simple models, the answer to the title question is that only these two ingredients are needed. However, for more realistic models, where in principle all wave numbers can be involved, other wave numbers are also important, specifically those of the second and higher reciprocal lattice vectors. We identify features in the particle pair interaction potentials that can suppress or encourage density modes with wave numbers associated with one of the regular crystalline orderings that compete with quasicrystals, enabling either the enhancement or suppression of quasicrystals in a generic class of systems.

Dispersive dynamics in the characteristic moving frame.

A mechanism for dispersion to automatically arise from the dispersionless Whitham Modulation equations (WMEs) is presented, relying on the use of a moving frame. The speed of this is chosen to be one of the characteristics which emerge from the linearization of the Whitham system, and assuming these are real (and thus the WMEs are hyperbolic) morphs the WMEs into the Korteweg-de Vries (KdV) equation in the boosted coordinate. Strikingly, the coefficients of the KdV equation are universal, in the sense that they are determined by abstract properties of the original Lagrangian density. Two illustrative examples of the theory are given to illustrate how the KdV may be constructed in practice. The first being a revisitation of the derivation of the KdV equation from shallow water flows, to highlight how the theory of this paper fits into the existing literature. The second is a complex Klein-Gordon system, providing a case where the KdV equation may only arise with the use of a moving frame.

The modulation of multiple phases leading to the modified Korteweg-de Vries equation.

This paper seeks to derive the modified Korteweg-de Vries (mKdV) equation using a novel approach from systems generated from abstract Lagrangians possessing a two-parameter symmetry group. The method utilises a modified modulation approach, which results in the mKdV emerging with coefficients related to the conservation laws possessed by the original Lagrangian system. Alongside this, an adaptation of the method of Kuramoto is developed, providing a simpler mechanism to determine the coefficients of the nonlinear term. The theory is illustrated using two examples of physical interest, one in stratified hydrodynamics and another using a coupled Nonlinear Schrödinger model, to illustrate how the criterion for the mKdV equation to emerge may be assessed and its coefficients generated.

Jejunal diverticulitis in a child.

Jejunal diverticular disease is rare and few cases have been documented in the literature. Here we report the first case of a child presenting with a perforated congenital jejunal diverticulum.

Reprinted article "Subintimal angioplasty of femoropopliteal artery occlusions: the long-term results".

The technique of subintimal angioplasty has been attempted on 200 consecutive femoropopliteal artery occlusions of median (range) length 11 (2-37) cm. The principle of the technique is to traverse the occlusion in the subintimal plane and recanalise by inflating the angioplasty balloon within the subintimal space. The technical success rate was 159/200 (80%) and was not significantly different for occlusions <10 cm (81%, n = 73), 11-20 cm (83%, n = 63) or >20 cm (68%, n = 23), p = 0.20. There were no deaths nor limb loss resulting from the procedure. The median (range) ankle-brachial pressure index increased from 0.61 (0.21-1.0) preangioplasty to 0.90 (0.26-1.50) postangioplasty. The actuarial haemodynamic patencies of technically successful procedures at 12 and 36 months were 71% and 58% respectively, the symptomatic patencies were 73% and 61%. A multiple regression analysis showed that smoking multiplied the risk of reocclusion by 2.70 (p < 0.001), each additional run-off vessel reduced the risk by 0.54 (p < 0.001) and the risk increased by 1.73 (p = 0.020) for every 10 cm of occlusion length. In conclusion, the technical success rate (80%) of subintimal angioplasty for femoropopliteal occlusions is unrelated to occlusion length and for all procedures, including technical failures, cumulative symptomatic and haemodynamic patencies of 46 and 48% can be achieved at 3 years. The factors influencing long-term patency were smoking, the number of calf run-off vessels and occlusion length.

Supervised exercise training for intermittent claudication: lasting benefit at three years.

OBJECTIVES: To assess the long-term outcome of supervised exercise training for intermittent claudication. METHODS: A prospective study was undertaken of all patients referred to a single centre with intermittent claudication (>46 m). Patients underwent supervised exercise training twice weekly for 10 weeks, with regular follow-up to 3 years. Actual Claudication Distance (ACD), Maximum Walking Distance (MWD) and ankle-brachial pressure indices (ABPI) were measured. RESULTS: In 202 patients the initial median ACD and MWD were 112 m and 197 m. Following exercise therapy both the median ACD and MWD increased to 266 m and 477 m at three months, increases of 237% and 242% respectively (p<0.001). At three years the median ACD and MWD were 250 m and 372 m, increases of 223% and 188% respectively (p<0.001). There was no significant change in ACD or MWD at 3 months compared to 1, 2 or 3 years. ABPI remained unchanged throughout. CONCLUSIONS: Supervised exercise training has long term benefit in patients with intermittent claudication. Results seen at 12 weeks are sustained at three years.

Oxidative stress indices in IDDM subjects with and without long-term diabetic complications.

BACKGROUND: Numerous animal and population studies of diabetes have identified markers of oxidative stress. However, for most markers that have been measured the results are not consistent. In addition, it is less clear whether oxidative stress is related to the development of diabetic complications. The objective of this study was to evaluate a series of plasma markers and leukocyte markers to test the hypothesis that type 1 Insulin Dependent Diabetes Mellitus (IDDM) subjects experience oxidative stress. A related question was whether markers of oxidative stress are higher in IDDM subjects who have developed long-term complications. METHODS: The study population consisted of 22 IDDM subjects with diabetic complications and 22 IDDM subjects without complications, both groups matched by age and gender and with similar HbA1c levels, and 16 nondiabetic control subjects. Plasma levels of organoperoxides were determined by the ferrous oxidation/xylenol orange (FOX) assay, malondialdehyde by the thiobarbituric acid (TBARS) assay, and vitamin E by HPLC. Mononuclear cells and polymorphonuclear cells were analyzed for ascorbic acid by HPLC and for glutathione (GSH) by enzymatic recycling. In addition, GSH peroxidase, GSH transferase and glucose-6-phosphate dehydrogenase levels were determined in both cell fractions. RESULTS: Plasma organoperoxides were significantly elevated in the IDDM subjects compared to controls (p = 0.02) while TBARS and vitamin E levels were not significantly different. In the IDDM subjects, mononuclear cell levels of ascorbic acid were significantly lower (p < 0.02) and levels of GSH were lower, approaching significance (p = 0.07), compared to controls. Ascorbic acid and GSH levels in polymorphonuclear cells were not significantly different between IDDM subjects and controls, nor were enzyme levels different. In addition, the plasma and intracellular indices of oxidative status in IDDM subjects were not different when IDDM subjects with complications were compared to IDDM subjects without complications. CONCLUSION: Demonstration of oxidative stress in IDDM subjects depends upon which markers are measured. This is in agreement with previous studies of oxidative stress in various disease states including diabetes. Plasma levels of organoperoxides may be the most reliable indicators of oxidative stress. However, it is unclear whether elevated plasma organoperoxides indicate a generalized systemic stress or are produced in localized areas. By comparison, oxidative stress indices determined with isolated blood cells may provide a clearer picture. Depressed levels of ascorbic acid and GSH were observed only in mononuclear cells, which are mainly long-lived T lymphocytes. Mononuclear cells antioxidant status may reflect systemic oxidative stress. In this study, neither plasma markers nor intracellular markers of oxidative stress were different in IDDM subjects with long-term diabetic complications compared to subjects without complications.

Qualitative research in family therapy: a substantive and methodological review.

Over the last decade, marriage and family therapy (MFT) researchers have developed a growing interest in qualitative research. In this article, we review substantive and methodological trends in the published qualitative studies within the MFT field. The research is compared and contrasted in the following areas: General topic, epistemological theory, methodological theory, sampling and sample, data collection, data analysis procedure, and approach to reliability and validity. We also provide recommendations for future research.

Lack of consensus in supervision.

This study describes what occurs when trainees and supervisors encounter a lack of consensus in supervision. We identified 120 episodes indicating a lack of consensus between a supervisor and a trainee during 23 hr of supervision. Qualitative analysis of the episodes described 10 supervisor responses, characterized as influence and evaluation, and eight trainee responses, characterized as cooperation and deference. The pattern of supervisor-trainee interaction was characterized by negotiation and collaboration. Supervisors and trainees collaborate to produce a presentation of the trainee as a competent clinician and a cooperative trainee. Supervisors identify deficiencies and offer requests in a subtle manner that appears open to modification, thus cooperating with the trainee's competent and cooperative image.

Prospective randomized controlled trial to compare skin staples and polypropylene for securing the mesh in inguinal hernia repair.

BACKGROUND: The Lichtenstein tension-free repair has become the standard method for repairing inguinal hernia in many surgical units. This study compared two methods of mesh fixation. METHODS: Fifty men undergoing unilateral primary Lichtenstein inguinal hernia repair under general anaesthesia were randomized into two groups. In the control group polypropylene mesh was secured with 2/0 polypropylene sutures and the skin closed with subcuticular 3/0 polydioxanone. In the study group polypropylene mesh was secured with skin staples and the skin was closed with staples from the same staple gun. Duration of the operation was recorded. Early follow-up was achieved by patient review at 6 weeks and postal questionnaire at 12 weeks. RESULTS: The operation was significantly shorter when staples were used (median 20 min 0 s versus 29 min 30 s, P < 0.001). There was no significant difference in the incidence of postoperative complications or pain score. The study group reported earlier return to normal activity (4 weeks 0 days versus 6 weeks 2 days, P < 0.01) although there was no difference in the time taken to return to work or driving. CONCLUSION: The use of skin staples to secure mesh in the Lichtenstein inguinal hernia repair significantly reduced the duration of the operation and was as effective as conventional mesh fixation with polypropylene in the short term.

A prospective survey of patients presenting with abdominal aortic aneurysm.

OBJECTIVES: To define the presentation and management of patients presenting with abdominal aortic aneurysm (AAA) DESIGN AND SETTING: A prospective survey was carried out of all patients presenting to hospitals within the Oxford region. MATERIALS AND METHODS: Data were collected by one surgeon in each hospital. Full details were collected onto data sheets. RESULTS: One hundred and ninety patients presented, 141 electively, 46 with ruptured AAA and three with acute AAAs. In 53 patients presenting electively the aneurysm was small and surveillance started. Fifty-six patients underwent an operation, three patients died. Of 46 patients with a ruptured aneurysm 24 (52%) died. In 11 no operation was carried out and all of these patients died within 24 h. Operative mortality was 13 of 35 patients (37%). More patients with a ruptured AAA were transferred to the teaching hospital compared with a district general hospital (p < 0.05). This was reflected in a lower operative mortality in the teaching hospital. CONCLUSIONS: The presentation of AAA in this study was approximately 15 per 100,000 population. Approximately one-third of patients presenting electively had small AAAs which required surveillance. A further third underwent an operation, the remaining patients being unfit. Approximately one-quarter of patients with a ruptured aneurysm did not undergo an operation. The operative mortality was 37%.

Structure-activity studies of L-canaline-mediated inhibition of porcine alanine aminotransferase.

L-Canaline [L-2-amino-4-(aminooxy)butanoic acid] (L-CAN) and a family of eleven structurally related analogs were synthesized and evaluated for their inhibitory effect on PLP-dependent alanine aminotransferase (AlaAT) (EC 2.6.1.2) obtained from porcine heart. These congeners were selected to determine the stereochemical, aliphatic chain length, and aminooxy substitutional effects on L-CAN-mediated inhibition of AlaAT activity. L-CAN was the most effective inhibitor of the tested compounds; 10(-7) M L-CAN elicited a 55% reduction in AlaAT activity after a 5 min exposure. This deleterious effect results from the ability of L-CAN to react avidly with PLP moiety of the enzyme to form a stable, L-CAN-PLP oxime. In contrast, the methyl and ethyl esters of L-CAN reduced AlaAT activity by only 8% and 6%, respectively. While all of the L-enantiomeric forms of the tested compound were more potent AlaAT inhibitors than their corresponding D-stereoisomers, the D-enantiomers, particularly D-canaline, were active. Chain shortening or lengthening dramatically curtailed L-CAN-mediated loss in AlaAT activity, but the replacement of the alpha-amino group with a hydrogen was of little consequence in this regard. AlaAT was treated with L-CAN in the presence of free PLP to assess PLP capacity to protect AlaAT against 10(7) M L-CAN-dependent inactivation. L-CAN retained approximately two-thirds of its inhibitory ability in the presence of equimolar PLP, but AlaAT inhibition was reduced 90% by a 10-fold excess of PLP over L-CAN.

Increased levels of methylglyoxal-metabolizing enzymes in mononuclear and polymorphonuclear cells from insulin-dependent diabetic patients with diabetic complications: aldose reductase, glyoxalase I, and glyoxalase II--a clinical research center study.

Levels of aldose reductase, glyoxalase I, and glyoxalase II in mononuclear and polymorphonuclear cells from insulin-dependent diabetes mellitus (IDDM) patients with long term diabetic complications were compared to levels in IDDM patients without complications and to those in nondiabetic controls. Cells were isolated from 22 asymptomatic long term IDDM patients, 22 symptomatic IDDM patients, and 16 controls, using a double gradient centrifugation procedure. Aldose reductase was determined by Western blots using polyclonal antiserum to human aldose reductase purified from skeletal muscle. Glyoxalase I and glyoxalase II were determined spectrophotometrically. Aldose reductase in mononuclear cells from symptomatic IDDM patients is significantly elevated compared to that in asymptomatic IDDM patients (mean +/- SEM, 0.96 +/- 0.20 vs. 0.46 +/- 0.08 microgram/mg protein; P < 0.02). Aldose reductase was not detected in polymorphonuclear cells. Glyoxalase I in mononuclear and polymorphonuclear cells from symptomatic IDDM patients is significantly elevated compared to that in controls [mean for mononuclear cells, 0.46 +/- 0.03 vs. 0.37 +/- 0.03 mumol/min.mg (P < 0.05); mean for polymorphonuclear cells, 0.16 +/- 0.01 vs. 0.10 +/- 0.01 mumol/min.mg (P < 0.002)]. Glyoxalase II is significantly elevated only in polymorphonuclear cells from symptomatic IDDM patients compared to controls (mean, 0.13 +/- 0.01 vs. 0.063 +/- 0.016 mumol/min.mg; P < 0.005). Glutathione peroxidase and glutathione S-transferase were not significantly different in these populations. Aldose reductase, glyoxalase I, and glyoxalase II are involved in the metabolism of methylglyoxal, suggesting that methylglyoxal may play a role in the etiology of diabetic complications.

A comparison of quality control methods applied to carotid endarterectomy.

OBJECTIVES: To compare the ability of continuous wave Doppler (CWD), B-mode ultrasound (BMU), angioscopy and transcranial Doppler (TCD) to detect technical error during carotid endarterectomy (CEA). DESIGN: A prospective, comparative study in 100 consecutive patients. SETTING: Leicester Royal Infirmary, Leicester, U.K. MATERIALS: Intraoperative TCD monitoring was performed using a SciMed PcDop 842 2 MHz TCD. An Olympus 2.8mm flexible angioscope was used to inspect the arterial lumen prior to restoration of bloodflow. After restoration of flow 10Mhz BMU images and 8Mhz CWD velocity spectra of carotid artery blood flow were obtained. CHIEF OUTCOME MEASURES: The detection of intimal flaps, thrombus, stenoses or other errors of surgical technique likely to result in perioperative morbidity. MAIN RESULTS: CWD and BMU images were technically inadequate in 9% and 24% of cases respectively and neither technique altered clinical management. Angioscopy demonstrated significant technical errors in 12 cases (four intimal flaps, thrombus in eight). TCD detected shunt malfunction in 13% of patients, emboli during dissection in 23% and early postoperative carotid artery thrombosis in three patients. CONCLUSIONS: A combination of TCD monitoring and completion angioscopy provided the maximum yield in terms of diagnosing technical error and establishing the cause of perioperative morbidity.

Clinical relevance of intraoperative embolization detected by transcranial Doppler ultrasonography during carotid endarterectomy: a prospective study of 100 patients.

A study was performed to investigate the clinical significance of microembolization detected by transcranial Doppler ultrasonography (TCD) by determining the quantity and character of emboli and correlating these with neurological and psychometric outcome, fundoscopy, automated visual field testing and computed tomographic brain scans in 100 consecutive patients undergoing carotid endarterectomy. Embolization was detected in 92 per cent of successfully monitored operations. Most emboli were characteristic of air and not associated with adverse clinical outcome. However, more than ten particulate emboli during initial carotid dissection correlated with a significant deterioration in postoperative cognitive function. A relationship between persistent particulate embolization in the immediate postoperative period, and both incipient carotid artery thrombosis and the development of major neurological deficits was observed. Immediate intervention, based on TCD evidence of embolization, has the potential to avert neurological deficits resulting from particulate embolization.

On-table diagnosis of incipient carotid artery thrombosis during carotid endarterectomy by transcranial Doppler scanning.

We present a case where transcranial Doppler ultrasound monitoring of a carotid endarterectomy enabled us to detect the incipient thrombosis of the operated artery before reversal of anesthesia. The use of transcranial Doppler ultrasound monitoring in carotid endarterectomy has the potential to detect this complication before serious neurologic damage has occurred and therefore reduce the morbidity and mortality rates associated with the operation.

Subintimal angioplasty of femoropopliteal artery occlusions: the long-term results.

The technique of subintimal angioplasty has been attempted on 200 consecutive femoropopliteal artery occlusions of median (range) length 11 (2-37) cm. The principle of the technique is to traverse the occlusion in the subintimal plane and recanalise by inflating the angioplasty balloon within the subintimal space. The technical success rate was 159/200 (80%) and was not significantly different for occlusions < 10 cm (81%, n = 73), 11-20 cm (83%, n = 63) or > 20 cm (68%, n = 23), p = 0.20. There were no deaths nor limb loss resulting from the procedure. The median (range) ankle-brachial pressure index increased from 0.61 (0.21-1.0) preangioplasty to 0.90 (0.26-1.50) postangioplasty. The actuarial haemodynamic patencies of technically successful procedures at 12 and 36 months were 71% and 58% respectively, the symptomatic patencies were 73% and 61%. A multiple regression analysis showed that smoking multiplied the risk of reocclusion by 2.70 (p < 0.001), each additional run-off vessel reduced the risk by 0.54 (p < 0.001) and the risk increased by 1.73 (p = 0.020) for every 10 cm of occlusion length. In conclusion, the technical success rate (80%) of subintimal angioplasty for femoropopliteal occlusions is unrelated to occlusion length and for all procedures, including technical failures, cumulative symptomatic and haemodynamic patencies of 46 and 48% can be achieved at 3 years. The factors influencing long-term patency were smoking, the number of calf run-off vessels and occlusion length.