Deautonomization by singularity confinement: an algebro-geometric justification

The ‘deautonomization’ of an integrable mapping of the plane consists in treating the free parameters in the mapping as functions of the independent variable, the precise expressions of which are to be determined with the help of a suitable criterion for integrability. Standard practice is to use the singularity confinement criterion and to require that singularities be confined at the very first opportunity. An algebro-geometrical analysis will show that confinement at a later stage leads to a non-integrable deautonomized system, thus justifying the standard singularity confinement approach. In particular, it will be shown on some selected examples of discrete Painlevé equations, how their regularization through blow-up yields exactly the same conditions on the parameters in the mapping as the singularity confinement criterion. Moreover, for all these examples, it will be shown that the conditions on the parameters are in fact equivalent to a linear transformation on part of the Picard group, obtained from the blow-up.

Microbial degradation of microcystin in Florida's freshwaters

Presence of microcystin (MC), a predominant freshwater algal toxin and a suspected liver carcinogen, in Florida's freshwaters poses serious health threat to humans and aquatic species. Being recalcitrant to conventional physical and chemical water treatment methods, biological methods of MC removal is widely researched. Water samples collected from five sites of Lake Okeechobee (LO) frequently exposed to toxic Microcystis blooms were used as inoculum for enrichment with microcystin LR (MC-LR) supplied as sole C and N source. After 20 days incubation, MC levels were analyzed using high performance liquid chromatography (HPLC). A bacterial consortium consisting of two isolates DC7 and DC8 from the Indian Prairie Canal sample showed over 74% toxin degradation at the end of day 20. Optimal temperature requirement for biodegradation was identified and phosphorus levels did not affect the MC biodegradation. Based on 16S rRNA sequence similarity the isolate DC8 was found to have a match with Microbacterium sp. and the DC7 isolate with Rhizobium gallicum (AY972457).

Breaking Instance-Independent Symmetries In Exact Graph Coloring

Code optimization and high level synthesis can be posed as constraint satisfaction and optimization problems, such as graph coloring used in register allocation. Graph coloring is also used to model more traditional CSPs relevant to AI, such as planning, time-tabling and scheduling. Provably optimal solutions may be desirable for commercial and defense applications. Additionally, for applications such as register allocation and code optimization, naturally-occurring instances of graph coloring are often small and can be solved optimally. A recent wave of improvements in algorithms for Boolean satisfiability (SAT) and 0-1 Integer Linear Programming (ILP) suggests generic problem-reduction methods, rather than problem-specific heuristics, because (1) heuristics may be upset by new constraints, (2) heuristics tend to ignore structure, and (3) many relevant problems are provably inapproximable. Problem reductions often lead to highly symmetric SAT instances, and symmetries are known to slow down SAT solvers. In this work, we compare several avenues for symmetry breaking, in particular when certain kinds of symmetry are present in all generated instances. Our focus on reducing CSPs to SAT allows us to leverage recent dramatic improvement in SAT solvers and automatically benefit from future progress. We can use a variety of black-box SAT solvers without modifying their source code because our symmetry-breaking techniques are static, i.e., we detect symmetries and add symmetry breaking predicates (SBPs) during pre-processing. An important result of our work is that among the types of instance-independent SBPs we studied and their combinations, the simplest and least complete constructions are the most effective. Our experiments also clearly indicate that instance-independent symmetries should mostly be processed together with instance-specific symmetries rather than at the specification level, contrary to what has been suggested in the literature.

Estimation of the macromolecular proton fraction and bound pool T2 in multiple sclerosis

This study used a model for magnetization transfer (MT) to estimate two underlying parameters: the macromolecular proton fraction (f) and the bound pool T2 (T2b) in patients with multiple sclerosis (MS). Sixty patients with clinically definite MS and 27 healthy controls were imaged using: (1) a dual echo fast spin echo sequence, (2) a MT sequence (with ten MT power and offset frequency combinations) and (3) proton density and T1 weighted sequences (for T1 relaxation time estimation). Fourteen normal-appearing white matter (NAWM) regions of interest (ROI) and six normal-appearing gray matter (NAGM) ROIs were outlined in all subjects. Lesions were also contoured in subjects affected by MS. The model was fitted to the data leading to estimates of T2b and f. Results showed that T2b was increased in lesions whereas f was reduced. In NAWM, f was decreased while T2b was only increased in secondary progressive MS. NAWM f correlated modestly with disability. Further studies are needed to investigate the pathological basis of the abnormalities observed.

Another approach to protons with constricted mobility in white matter: pilot studies using wideline and high-resolution NMR spectroscopy

We report a new approach for the identification of an independent method of studying the semi-solid pool of protons, i.e., protons with constrained motion as a result of being bound to lipid and protein matrices. These protons cannot be observed using conventional imaging techniques since their transverse relaxation times are much shorter than the minimum echo times that are currently available on clinical scanners. In this pilot study, in vitro multicomponent transverse relaxation experiments were made on human white matter slices, fixed in formalin (7 normal and 5 with multiple sclerosis). The transverse relaxation decay curves were multiexponential and were decomposed to yield three primary components. The shortest T(2) component that we obtained (a component too short to be seen by in vivo methods) was of the order of microseconds. We hypothesize that this might correspond to the macromolecular pool of lipid protons trapped within the myelin sheaths. To our knowledge, this is the first attempt at extracting this ultra short T(2) component from human white matter. Subsequently, an attempt was made to directly detect the lipid protons in a proton NMR spectrum and, if possible, measure their concentration in some of the tissues, using the technique of magic angle spinning.

Quantitative magnetization transfer mapping of bound protons in multiple sclerosis

Quantitative analysis of magnetization transfer images has the potential to allow a more thorough characterization of the protons, both bound and free, in a tissue by extracting a number of parameters relating to the NMR properties of the protons and their local environment. This work develops previously presented techniques to produce estimates of parameters such as the bound proton fraction, f, and the transverse relaxation time of the bound pool, T(2B), for the whole brain in a clinically acceptable imaging time. This is achieved by limiting the number of data collected (typically to 10); to collect 28 5-mm slices with a reconstructed resolution of 0.94 x 0.94 mm. The protocol takes 82 sec per data point. The fitting technique is assessed against previous work and for fitting failures. Maps and analysis are presented from a group of seven controls and 20 multiple sclerosis patients. The maps show that the parameters are sensitive to tissue-specific differences and can detect pathological change within lesions. Statistically significant differences in parameters such as T(2B) and f are seen between normal-appearing white matter, multiple sclerosis lesions, and control white matter. Whole-brain histograms of these parameters are also presented, showing differences between patients and controls.

Preliminary magnetic resonance study of the macromolecular proton fraction in white matter: a potential marker of myelin?

We report on a new quantitative magnetization transfer (MT) technique that allows for the in vivo estimation of the macromolecular proton fraction (f) and the bound pool T2 relaxation time (T2b), whilst permitting whole brain coverage. In this pilot study, five subjects with multiple sclerosis (MS) and five healthy controls were studied. Both f and T2b were significantly different between MS lesions and normal control white matter (WM). Relationships between f and T1 relaxation time [Spearmans rank correlation coefficient (r(s)) = -0.97, P < 0.001] and f and the magnetization transfer ratio (MTR; r(s) = 0.80, P < 0.001) were observed. Compared with MTR, f and T2b have the potential advantage of relative independence from MT acquisition protocol while offering more pathologically specific information. In particular, f may provide a more direct indication of myelin content in WM.

Precise estimate of fundamental in-vivo MT parameters in human brain in clinically feasible times

A methodology is presented for extracting precise quantitative MT parameters using a magnetisation-prepared spoiled gradient echo sequence. This method, based on a new mathematical model, provides relaxation parameters for human brain in-vitro and in-vivo. The in-vivo parameters have been obtained from three different regions of normal white matter: occipital white matter, frontal white matter and centrum semiovale; two regions of normal grey matter: cerebral cortex and cerebellum, and from five regions with MS lesions. All this has been achieved using MT images collected within a timeframe that is clinically feasible. We hope that this new technique will shed light on the properties and dynamics of water compartments within the brain.

Rapid flow cytometric susceptibility testing of Candida albicans

A rapid flow cytometric assay for in vitro antifungal drug susceptibility testing was developed by adapting the proposed reference method for broth macrodilution testing of yeasts. Membrane permeability changes caused by the antifungal agent were measured by flow cytometry using propidium iodide, a nucleic acid-binding fluorochrome largely excluded by the intact cell membrane. We determined the in vitro susceptibility of 31 Candida albicans isolates and two quality control strains (Candida parapsilosis ATCC 22019 and Candida krusei ATCC 6258) to amphotericin B and fluconazole. Amphotericin B MICs ranged from 0.03 to 2.0 microg/ml, while fluconazole MICs ranged from 0.125 to 128 microg/ml. This method results in clear-cut endpoints that were reproducible. Four-hour incubation was required for fluconazole, whereas a 2-h incubation was sufficient for amphotericin B to provide MICs comparable to the reference macrodilution method developed by the National Committee for Clinical Laboratory Standards Subcommittee on Antifungal Susceptibility Tests. Results of these studies show that flow cytometry provides a rapid and sensitive in vitro method for antifungal susceptibility testing of C. albicans.

Fungal colonization in gastric ulcers

Until now studies on fungal colonization of gastric ulcers were retrospective involving small series of patients. This prospective study of 50 patients with gastric ulcers (25 benign and 25 malignant) revealed colonization by Candida in 17 (34%) cases. There was no significant difference in colonization between benign and malignant ulcers. Follow up revealed no difference in healing of ulcers with or without fungal colonization.

Penicillium species causing onychomycosis

Onychomycosis caused by mould infection is rare. A 40 year old male patient presented with dystrophic finger nails and multiple, erythematous lesions with slightly raised borders and scaling all over the body. The patient was a known diabetic. He did not respond to griseofulvin. Samples from nails and skin scales were cultured. From the nails, Penicillium species and from the skin scales. Trichophyton rubrum were isolated. Ketoconazole therapy (200 mg twice daily x 4 mths) led to complete cure with negative cultures and normalization of nails.

Molds in onychomycosis

BACKGROUND

Onychomycosis is a major cause of nail dystrophy. The causative organisms in onychomycosis are dermatophytes, Candida and molds. A variety of molds have been isolated from nails.

METHODS

Nail scrapings and clippings were collected from 100 cases and inoculated on slants containing SDA with cycloheximide 0.5 mg/mL, chloramphenicol 0.05 mg/mL, and SDA with chloramphenicol 0.05 mg/mL.

RESULTS

The culture positivity rate for molds was 22%. The predominant mold isolates were Aspergillus species (86.4%, Fusarium oxysporum (4.5%), Curvularia species (4.5%) and Penicillium species (4.5%).

CONCLUSION

Primary invasion of nails by molds can cause onychomycosis.

Hemorheologic approach in the treatment of diabetic foot ulcers

Pentoxifylline, a new trisubstituted methylxanthine derivative, is the most well known of a new group of hemorheologic agents. It has been shown to improve hemorheologic abnormalities associated with diabetes and atherosclerosis. The authors examined the role of pentoxifylline in the treatment of diabetic foot ulcers. Forty diabetic patients with foot ulcerations were included in the study, 20 of whom received conventional therapy and 20 received pentoxifylline (400 mg three times a day) in addition. Healing of ulcers after eight weeks of treatment was significantly higher in those on pentoxifylline, and the patients needed less mutilating surgery. Administration of pentoxifylline in addition to conventional therapy was significantly superior in the management of diabetic foot ulcers.

Ultrasound-guided needle aspiration of amoebic liver abscess

This prospective study was carried out on 200 patients with clinically, ultrasonographically and serologically confirmed amoebic liver abscess. The role of ultrasound-guided needle aspiration in addition to medications was evaluated compared to drug treatment alone. Both the groups were monitored clinically and sonographically for up to 6 months after diagnosis. The initial response (after 15 days) was better in the aspirated group (P < 0.05) but resolution of abscess after 6 months were similar. There was a more rapid clinical response in the aspirated group, particularly in those with larger (> 6 cm) abscesses and there were no complications. Percutaneous ultrasound-guided needle aspiration is a safe diagnostic and therapeutic approach which enhances clinical recovery, accelerates resolution, especially in large abscesses, and prevents complications.

Glycemic control and its relationship to diabetic foot ulcers

Glucosylhaemoglobin (HbA1) was estimated in 60 diabetic patients, 30 with foot ulceration and 30 without foot lesions. Peripheral neuropathy and vascular disease were commonly found in the ulcer' group. The mean HbA1 level in diabetics without ulcers was 9.77 +/- 2.34, while the corresponding level in diabetics with ulcers was 14.14 +/- 3.63. The difference in values is statistically highly significant (p less than 0.001) suggesting that foot ulcers are more likely to occur in poorly controlled diabetic patients.

Bacteriology of diabetic foot ulcers

Seventy five diabetic foot ulcers were cultured using optimal aerobic and anaerobic microbiologic techniques. There were a total of 223 isolates (162 aerobes and 61 anaerobes) representing an average of 2.97 bacterial species per specimen. Mixed organisms were the most common isolates. Staphylococcus aureus was the commonest isolate being recovered in 60% of cases. Anaerobic organisms were isolated in 46 patients (61.33%) and the most frequent anaerobe isolated was Bacteroides fragilis. The other organisms predominantly isolated were Proteus, Klebsiella, Pseudomonas, Peptoccus and Clostridia. Antibiogram showed discouraging pattern with commonly used antibiotics. Metronidazole and gentamicin were the most effective antimicrobial agents against anaerobic and aerobic organisms respectively. Appreciation of the causative organisms in diabetic foot and their antibiotic sensitivity is essential for institution of appropriate antibiotic therapy.

Clinico-pathological profile of lymphomas in south India: a prospective rural referral hospital study of 103 cases

A prospective clinical and histopathological study of 103 patients with lymphomas is reported. Of these, 72 (69.9%) had non-Hodgkin's lymphoma (NHL) and 31 (30.1%) had Hodgkin's lymphoma (HL). The median age at presentation was 34 and 43 years for Hodgkin's and non-Hodgkin's lymphoma respectively, which is lower than that seen in the West. Fever and superficial lymphadenopathy were the commonest presenting features and 'B' symptoms were present in over 60% of both groups. Seventy-five per cent of NHL and 64.5% of HL presented in stages III and IV of the disease.

Aetiology of diabetic foot ulceration

A prospective study of 150 diabetic patients was undertaken with the aim of determining the factors associated with the development of foot ulcerations. Seventy five patients had foot ulceration and 75 had no foot lesions. Peripheral (78.7%) and autonomic (38.7%) neuropathy were more commonly found in the "ulcer" group, as were vascular insufficiency (49.3%) and hyperlipidaemia (60%). Renal failure (9.3%) and ketoacidosis (20%) were also commoner in patients with foot ulceration. Most, if not all, of the aetiological factors are related to prolonged uncontrolled hyperglycaemia.

Electrocardiographic abnormalities in cerebrovascular accidents

The electrocardiographic abnormalities found in 100 patients with acute cerebrovascular disease and previously normal hearts are described. The abnormalities were more often seen in patients with intracerebral and subarachnoid hemorrhages. The most common changes were Q-Tc Prolongation and ST segment and T wave abnormalities. The mechanisms of these electrocardiographic abnormalities appear to be multiple.

Nosocomial complicated urinary tract infections: A rural based referral hospital study

A three-year retrospective study of urinary tract infection in 891 patients was conducted at a rural based hospital in coastal Karnataka, South India. Eighty-eight per cent of the patients had complicated urinary tract infections with predominantly nosocomial organisms such as Klebsiella as opposed to the normally more common uncomplicated infection with E. coli. The reasons for this seem to be the delay in referral, resulting in late correction of the underlying structural causes of the infections. In our series of patients, the association of prolonged indwelling catheter drainage with complicated urinary tract infection suggests that non-urologists should adopt alternative measures such as clean intermittent catheterization, and reduce the period of indwelling catheters to the shortest time possible. More judicious selection and timing of antibiotic therapy might prevent the development of resistant organisms.

Serum apoproteins A and B and the lecithin: cholesterol acyl transferase activities in liver cirrhosis and hepatic coma patients

Serum apoproteins A and B and LCAT activities were estimated in 80 patients, 46 with posthepatic cirrhosis and 34 with alcoholic cirrhosis. The cirrhosis patients were also divided into compensated, decompensated, and hepatic coma subgroups. Apo-A and LCAT activities were significantly decreased in both cirrhotic groups without any significant difference between posthepatitic and alcoholic cirrhotic groups, while Apo-B was decreased in hepatic coma patients only. The decompensated cirrhosis patients showed lower Apo-A levels than the compensated cirrhosis patients and hepatic coma patients showed still lower levels compared to decompensated subgroup, while no significant decrease was observed in LCAT activities between compensated and decompensated cirrhosis patients. Apo-A level was correlated more significantly with serum albumin level than the LCAT activity. The study confirms that Apo-A level is highly related to the degree of liver injury and also suggests that this decrease may be mainly due to impaired liver synthesis and that the serum levels of Apo-A and Apo-B can be utilized in the differential diagnosis of chronic liver diseases.