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PubMed2004

Effect of high-temperature on high-performance liquid chromatography column stability and performance under temperature-programmed conditions.

Six commercially available analytical (4.1 or 4.6 mm i.d.) columns were evaluated under temperature-programmed high-temperature liquid chromatography (HTLC) conditions to access their stability and performance at extreme temperatures. Seven components consisting of acidic, basic and neutral compounds were analyzed under temperature-programmed conditions and solvent gradient conditions using three different mobile phase compositions (acidic, basic and neutral). Each column was checked with a two-component test mix at various stages of the evaluation to look for signs of stationary phase collapse. Three zirconia based stationary phases studied exhibited column bleed under temperature-programmed conditions. The other three columns, a polydentate silica column, a polystyrene-divinylbenzene (PS-DVB) polymeric column, and a graphitic carbon column performed well with no evidence of stationary phase degradation. The R.S.D. for the retention times and efficiencies were less than 10% for most conditions, and not more than 15% during the course of the evaluation for each column. The polydentate silica stationary phase was temperature programmed to 100 degrees C, the PS-DVB stationary phase was temperature programmed up to 150 degrees C, and the graphitic carbon column was used with temperature programming up to 200 degrees C. Comparable peak capacities and similar retention behaviors were observed under solvent gradient and temperature-programmed conditions. Temperature programming with dynamic mobile phase preheating can replace solvent gradient analysis without a loss of peak capacity when used with 4.1 or 4.6 mm columns.

Chromatography, High Pressure Liquid↗
PubMed2006

Nonlinear analysis of wheezes using wavelet bicoherence.

Wheezes, as being abnormal breath sounds, are observed in patients with obstructive pulmonary diseases, such as asthma. The aim of this study was to capture and analyze the nonlinear characteristics of asthmatic wheezes, reflected in the quadrature phase coupling of their harmonics, as they evolve over time within the breathing cycle. To achieve this, the continuous wavelet transform (CWT) was combined with third-order statistics/spectra. Wheezes from patients with diagnosed asthma were drawn from a lung sound database and analyzed in the time-bi-frequency domain. The analysis results justified the efficient performance of this combinatory approach to reveal and quantify the evolution of the nonlinearities of wheezes with time.

Algorithms↗
PubMed2006

Modeling fire-induced smoke spread and carbon monoxide transportation in a long channel: Fire Dynamics Simulator comparisons with measured data.

Smoke and toxic gases, such as carbon monoxide, are the most fatal factors in fires. This paper models fire-induced smoke spread and carbon monoxide transportation in an 88m long channel by Fire Dynamics Simulator (FDS) with large eddy simulation (LES). FDS is now a well-founded fire dynamics computational fluid dynamic (CFD) program, which was developed by National Institute of Standards and Technology (NIST). Two full scale experiments with fire sizes of 0.75 and 1.6MW were conducted in this channel to validate the program. The spread of the fire-induced smoke flow together with the smoke temperature distribution along the channel, and the carbon monoxide concentration at an assigned position were measured. The FDS simulation results were compared with experimental data with fairly good agreement demonstrated. The validation work is then extended to numerically study the carbon monoxide concentration distribution, both vertically and longitudinally, in this long channel. Results showed that carbon monoxide concentration increase linearly with the height above the floor and decreases exponentially with the distance away from the fire source.

Carbon Monoxide↗
PubMed2006

Solution structure of amphibian tachykinin Uperolein bound to DPC micelles.

Uperolein, a physalaemin-like endecapeptide, has been shown to be selective for Neurokinin 1 receptor. As a first step towards understanding the structure-activity relationship, we report the membrane-induced structure of Uperolein with the aid of circular dichroism and 2D (1)H NMR spectroscopy. Sequence-specific resonance assignments of protons have been made using correlation spectroscopy (TOCSY, DQF-COSY) and NOESY spectroscopy. The interproton distance constraints and dihedral angle constraints have been utilized to generate a family of structures using torsion angle molecular dynamics within program DYANA. The conformational range of the peptide revealed by NMR and CD studies has been analysed in terms of characteristic secondary features. Analysis of NMR data indicates that the global fold of Uperolein can be explained in terms of equilibrium between 3(10)-helix and alpha-helix from residues 5 to 11. An extended highly flexible N-terminus displays some degree of order and a possible turn structure. A comparison between the structures of Uperolein and Substance P, a prototype and endogenous Neurokinin 1 receptor agonist, indicates several common features in the distribution of hydrophobic and hydrophilic residues. Both the peptides show an amphiphilic character towards the middle region. The similarities suggest that the molecules interact with the receptor in an analogous manner.

Amino Acid Sequence↗
PubMed2026

Feeding the epigenome: EZH2 as a metabolic integrator of cell fate in development and cancer.

Epigenetic regulation is intimately linked to cellular metabolism, enabling environmental and nutritional cues to shape gene expression programs through dynamic modifications of chromatin structure. This metabolism-epigenetics interface is mediated, in part, by the dependence of chromatin-modifying enzymes on key metabolites, including S-adenosylmethionine (SAM), acetyl-CoA, UDP-GlcNAc, and α-ketoglutarate, which serve as substrates or cofactors for DNA and histone modifications. Among these regulators, EZH2, the catalytic subunit of Polycomb Repressive Complex 2 (PRC2), has emerged as a key mediator linking metabolic state to epigenetic regulation by translating metabolic inputs into changes in chromatin architecture and gene expression. EZH2 governs developmental cell fate through H3K27me3-mediated gene repression and is frequently dysregulated in cancer, where it promotes dedifferentiation, tumor progression, and metabolic reprogramming. Importantly, EZH2 activity is itself modulated by cellular metabolic status through posttranslational modifications, including phosphorylation, acetylation, methylation, ubiquitination, and O-GlcNAcylation, which influence its stability, catalytic activity, and chromatin-binding capacity. These modifications are responsive to nutrient availability and signaling pathways involving glucose, SAM, NAD+, and other metabolic intermediates. Consequently, disruption of this finely tuned regulatory network can contribute to developmental abnormalities, metabolic dysfunction, and oncogenesis. In this review, we examine the molecular mechanisms governing EZH2 regulation and discuss how metabolic control of EZH2 shapes chromatin dynamics, cell fate decisions, and disease pathogenesis. Elucidating how metabolic signals modulate EZH2 activity will advance our understanding of development and disease while uncovering potential therapeutic opportunities to target metabolism-driven epigenetic dysregulation.

Humans↗
PubMed1996

Psychological long-term effects of sterilization on anxiety and depression.

Two-thousand cases (500 women and 500 men with sterilization; 500 women and 500 men without sterilization) in two counties and two cities in Sichuan, China, were investigated between 15 September 1992 and 30 April 1993. Information was obtained about their age, parity, marriage, contraceptives, social behavior, and present psychological characteristics. CES-D, SAS, and E.P.Q. scales were used to assess the depressive symptomatology, anxiety, and personality of the subjects. The results revealed that sterilization psychologically affected the depressive symptoms and anxiety under the neutral personality. In addition, depressive symptoms and anxiety were related to the subjects' age, educational level, income, operative doctors' attitudes to sterilization acceptors, and subjects' understanding of the sterilization.

Adult↗
PubMed1986

Married women's dissatisfaction with tubal sterilization and vasectomy at first-year follow-up: effects of perceived spousal dominance.

Examination of first-year follow-up data obtained from 234 tubal ligation women and 154 vasectomy wives indicated a very low incidence of actual regret in both groups. However, use of a broader measure of satisfaction/dissatisfaction indicated that tubal ligation women had significantly more positive feelings about the sterilization decision than did vasectomy wives. Results of a series of multivariate statistical analyses demonstrated that group differences in satisfaction were related to (1) the disproportionate prevalence of perceived male control (particularly extensive control) over reproductive decisions among vasectomy wives and the negative effect it had upon subjects in both groups and (2) the disproportionate prevalence of female control over reproductive decision-making among tubal ligation women and the positive effect it had among subjects in this group. Study results point to the importance of couple counseling and exercising control over one's own body.

Adult↗
PubMed1992

Nonoperative management of multilevel lumbar disk herniations in an adolescent athlete.

Herniated lumbar nucleus pulposus is rare in the pediatric age-group; for surgically proven cases, the estimated prevalence is between 0.8 and 3.2%. Most of the current literature indicates that herniated nucleus pulposus in pediatric patients differs from that in adult patients in epidemiologic characteristics, clinical manifestations, and frequency of associated neurologic findings. To our knowledge, the current case is the first published report of lumbar disk herniations at three levels in a 15-year-old male adolescent, whose abnormalities were verified by computed tomography and myelography. Most investigators recommend surgical treatment; however, our patient had good results with nonoperative management that consisted of nonsteroid anti-inflammatory drugs, passive extension, lumbar traction, segmental mobilization, and a progressive program of dynamic lumbar stabilization exercises. The patient is now asymptomatic and able to participate in selected limited contact sports and most farm activities; however, contact sports are prohibited for 1 year. If follow-up computed tomographic imaging of the lumbar spine demonstrates no progression of the disk abnormalities and if the patient remains asymptomatic, he could consider participation in contact sports after necessary conditioning.

Adolescent↗
PubMed1999

Adolescent gynecology in the office setting.

As stated by the Committee on Adolescence of the AAP, All pediatricians who choose to see teenagers should be able to provide counseling about sexual behavior, education on contraceptive methods and prevention of sexually transmitted diseases, and assistance with access to family planning services, preferably in the office or, if necessary, by referral. Expansion of skills and office capabilities to provide routine reproductive health care for adolescents, including pelvic examinations, annual Pap tests, diagnoses of pregnancy, diagnoses and treatment of sexually transmitted diseases, and the prescription of contraceptives, is also encouraged. Pediatricians who have longstanding relationships with their patients, and who are admired and trusted are ideal for providing this care.

Adolescent↗
PubMedDate not supplied

The Gambian National Impregnated Bed Net Programme: evaluation of effectiveness by means of case-control studies.

Two case-control studies, one on mortality and the other on malaria morbidity, were carried out in order to evaluate the impact of the Gambian National Insecticide Bed Net Programme during the second year of intervention and to explore the feasibility of such a study for the evaluation of programme effectiveness. For the mortality study, children 1-9 years old who died during the 1993 rainy season were matched by age and sex with 2 healthy controls from the same village. For the morbidity study, children 1-9 years old attending Fatoto or Jahalia Health Centres in The Gambia and who had fever and parasitaemia > or = 5000/microL were matched by age with a child attending the health centres without fever or parasitaemia. An additional healthy control was recruited from the case's village. No impact of insecticide-treated bed nets on mortality was detected and this was in keeping with the results obtained by prospective surveillance. A protective effect of insecticide-treated nets on malaria morbidity was detected when cases were compared with controls recruited at the health centres. However, this disappeared when cases were compared with controls recruited from the cases' villages. The mortality case-control study suggested that reducing the time between onset of disease and treatment may have an important impact on childhood mortality. In order to calculate programme cost-effectiveness, important for informed resource allocations to be made by health managers, it is essential to obtain evidence of effectiveness. This can be done by means of case-control studies, which are easier to carry out and require fewer resources than prospective surveillance. Nevertheless, it is necessary to be conscious of their pitfalls, particularly of the bias involved in the choice of cases and controls. The measurement of insecticide on the nets of the cases or controls is essential for such studies.

Case-Control Studies↗
PubMed1995

Mortality and morbidity from malaria in Gambian children after introduction of an impregnated bednet programme.

After the success of a controlled trial of insecticide-treated bednets in lowering child mortality, The Gambia initiated a National Insecticide Impregnated Bednet Programme (NIBP) in 1992 with the objective of introducing this form of malaria control into all large villages in The Gambia. Five areas (population 115,895) were chosen as sentinel sites for evaluation of the NIBP. During the first year of intervention a 25% reduction was achieved in all-cause mortality in children 1-9 years old living in treated villages (rate ratio 0.75 [95% CI 0.57-0.98], p = 0.04). If one area where the programme was ineffective was excluded, the reduction was 38% (0.62 [0.46-0.83), p = 0.001). A decrease in rates of parasitaemia and high-density parasitaemia, an increase in mean packed-cell volume (rate ratio 0.75 [95% CI 0.59-0.98], p = 0.04) and an improvement in the nutritional status of children living in treated villages were also detected. In a country such as The Gambia, where nets were widely used and which has a good primary health care system, it is possible to achieve insecticide-treatment of bednets at a national level with a significant reduction in child mortality; but at a cost which the country cannot afford.

Bedding and Linens↗
PubMed1992

A preliminary evaluation of education material prepared for the Safe Motherhood Initiative Educational Project.

Maternal death is a tragedy which is all too familiar in much of the world. As part of the Safe Motherhood Initiative the World Health Organization is developing and producing a learning package designed specifically for midwives. Through a modular system of learning incorporating aspects of community, prevention, treatment and follow-up the package seeks to address the five main causes of maternal mortality. In this paper the first pre-testing of the educational material in an African country is described. The extent of the evaluation is limited at this early stage but the initial analysis of the results is encouraging and have led to modifications of the original package. The evaluation has confirmed that a tool such as this package can be a valuable resource for midwife teachers attempting to improve the relevance of education for their midwifery students. The midwifery students whilst being 'with woman' in childbirth are also grappling with the realities of death in their everyday practice. The educational package has also reinforced the sense of urgency fundamental to completing this extensive project so that it can be made available to midwives throughout the developing world at the earliest opportunity.

Botswana↗
PubMed2000

Wavelet-based enhancement for detection of left ventricular myocardial boundaries in magnetic resonance images.

MRI is noninvasive and generates clear images, giving it great potential as a diagnostic instrument. However, current methods of image analysis are too time-consuming for dynamic systems such as the cardiovascular system. Since dynamic imagery generate a huge number of images, a computer aided machine vision diagnostic tool is essential for implementing MRI-based measurement. In this paper, a wavelet-based image technique is applied to enhance left ventricular endocardial and epicardial profiles as the preprocessor for a dynamic programming-based automatic border detection algorithm. Statistical tests are conducted to verify the performance of the enhancement technique by comparing borders manually drawn with 1. borders generated from the enhanced images, and 2. borders generated for the original images.

Algorithms↗
PubMed1997

Short stay surgery for breast cancer: an audit of an experience in a regional cancer centre in northern India.

At the Institute Rotary Cancer Hospital, AIIMS, New Delhi, 246 patients of breast cancer were operated on from June 1993 to June 1996; 82 suitable patients were discharged within 48 h (short stay surgery, SSS) after surgery and 164 were discharged after 48 h (conventional stay surgery, CSS). After discharge, patients of both groups were followed in the outpatient clinic until the removal of sutures and drains. There was no mortality or readmission for a complication in either group. Mean post-operative hospital stay was 1.5 days in the SSS group, and 3.3 days in the CSS group. There was no statistically significant difference in the incidence of post-operative complications like wound infection (4.8% vs 4.2%), flap necrosis (6% vs 5.4%), seroma (14% vs 19%), and the average number of hospital visits (3.42 vs 3.2) in SSS and CSS groups, respectively. Patient acceptance of early discharge was good except in the day care group. The study supports the safety and feasibility of short stay surgery for breast cancer in certain circumstances for properly selected patients.

Adult↗
PubMed2001

Paclitaxel and docetaxel in prostate cancer.

Although their ultimate value in prostate cancer therapy remains to be defined in randomized trials, docetaxel and paclitaxel are active agents in HRPC. Combination therapies using either of these taxanes plus oral EMP show reproducible antitumor activity that appears to be greater and more durable than that of single-agent treatment. Although the optimal combination and schedule have not been determined, weekly paclitaxel and EMP and docetaxel given every 3 weeks or by weekly infusion with EMP are useful treatment options for patients with progressive HRPC. The gastrointestinal toxicity of EMP has been reduced by intermittent rather than continuous administration, and other toxicities may be reduced further by use of intravenous EMP. Although there has been progress, the median time to progression of 5 to 6 months for current taxane-based therapies suggests that they will not have major impact on overall survival for patients with HRPC. Greater benefit may be possible earlier in the course of prostate cancer, and the activity of the taxane-EMP combinations is sufficient to justify clinical trials of adjuvant or neoadjuvant chemotherapy for selected groups of patients with locally advanced and poor-prognosis tumors. Armed with many new molecularly targeted agents that may interact favorably with taxanes, it should be possible to build on current antimicrotubule regimens to improve activity in HRPC. Taxane-EMP combinations provide a platform on which to test additional agents that may enhance the apoptotic response or circumvent cellular stress adaptations that confer drug resistance. Further elucidation of signaling pathways that regulate microtubule dynamics and programmed cell death after exposure to microtubule inhibitors would provide a more rational guide for integrating specific inhibitors of signal transduction with current taxane-based therapies. Pharmacokinetic and pharmacodynamic studies will play a key role in the development of future taxane-based therapies for prostate cancer.

Adenocarcinoma↗
PubMedDate not supplied

A multiscale optimization approach for the dynamic contour-based boundary detection issue.

We present a new multiscale approach for deformable contour optimization. The method relies on a multigrid minimization method and a coarse-to-fine relaxation algorithm. This approach consists in minimizing a cascade of optimization problems of reduced and increasing complexity instead of considering the minimization problem on the full and original configuration space. Contrary to classical multiresolution algorithms, no reduction of image is applied. The family of defined energy functions are derived from the original (full resolution) objective function, ensuring that the same function is handled at each scale and that the energy decreases at each step of the deformable contour minimization process. The efficiency and the speed of this multiscale optimization strategy is demonstrated in the difficult context of the minimization of a region-based contour energy function ensuring the boundary detection of anatomical structures in ultrasound medical imagery. In this context, the proposed multiscale segmentation method is compared to other classical region-based segmentation approaches such as Maximum Likelihood or Markov Random Field-based segmentation techniques. We also extend this multiscale segmentation strategy to active contour models using a classical edge-based likelihood approach. Finally, time and performance analysis of this approach, compared to the (commonly used) dynamic programming-based optimization procedure, is given and allows to attest the accuracy and the speed of the proposed method.

Algorithms↗
PubMed1992

Infant and child mortality in rural Egypt.

This research examines determinants of infant and child mortality in rural Egypt, primarily the effects of household economic status and the availability of health services. Certain features of the health service environment affect survival in the neonatal period. In early childhood, survival chances improve markedly as income increases and if the household depends almost exclusively on employment income. In infancy and in early childhood, mortality is strongly associated with region of residence and maternal demographic characteristics, and is weakly associated with parental schooling.

Child, Preschool↗