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PubMed2004

Optimizing the HIV/AIDS informed consent process in India.

BACKGROUND: While the basic ethical issues regarding consent may be universal to all countries, the consent procedures required by international review boards which include detailed scientific and legal information, may not be optimal when administered within certain populations. The time and the technicalities of the process itself intimidate individuals in societies where literacy and awareness about medical and legal rights is low. METHODS: In this study, we examined pregnant women's understanding of group education and counseling (GEC) about HIV/AIDS provided within an antenatal clinic in Maharashtra, India. We then enhanced the GEC process with the use of culturally appropriate visual aids and assessed the subsequent changes in women's understanding of informed consent issues. RESULTS: We found the use of visual aids during group counseling sessions increased women's overall understanding of key issues regarding informed consent from 38% to 72%. Moreover, if these same visuals were reinforced during individual counseling, improvements in women's overall comprehension rose to 96%. CONCLUSIONS: This study demonstrates that complex constructs such as informed consent can be conveyed in populations with little education and within busy government hospital settings, and that the standard model may not be sufficient to ensure true informed consent.

AIDS Serodiagnosis↗

PubMed2007

Application of immunomagnetic cell enrichment in combination with RT-PCR for the detection of rare circulating head and neck tumor cells in human peripheral blood.

Detection of rare, circulating tumor cells (CTC's) in human peripheral blood is a potential indicator of prognosis and diagnosis in oncology. Typical methods to detect these CTC's are either by immunocytochemistry (ICCS) or RT-PCR. However without accurate, rapid, and reproducible enrichment processes, these detection techniques are labor intensive and/or unreliable. In this article, a repeatable enrichment process that included a flow-through immunomagnetic cell separation system, the quadrupole magnetic sorter (QMS) was optimized with the aid of a statistical analysis software package. The QMS was operated in a negative mode of operation by immunomagnetically targeting normal human peripheral blood lymphocytes (PBL) through the CD45 surface marker. Three head and neck squamous carcinoma cell lines (HNSCC), Detroit-562, SCC-4, and CAL-27, were used to determine the sensitivity of RT-PCR for the epidermal growth factor receptor (EGFR) in spiked PBL. The detection purity needed for detection was found to be one cell in 10(4), one cell in 10(3), and one cell in 10(5) for the Detroit-562, SCC-4, and CAL-27, respectively. The actual number of cancer cells needed for RT-PCR detection ranged from 30 to 1 cell. To mimic the potential concentration of rare CTC present in peripheral blood of cancer patients, the spiking concentration was chosen to be one cancer cell per 10(5) total leukocytes from healthy donors. Using a single step immunomagnetic labeling, the final, optimized enrichment process produced a 57.6 +/- 30.3-fold (n = 6) enrichment of the rare cancer cells with a final cancer cell recovery of (77.8 +/- 6.6)%.

Biomarkers, Tumor↗

PubMed1990

Modeling of cardiac rhythms. A signal-processing perspective.

The authors describe their perspective on the modeling of cardiac rhythms as a component of cardiac arrhythmia signal-processing algorithms. They emphasize that these models are for a specific end purpose and that the aspects of cardiac behavior that are captured by the models are only those relevant for the development of the signal-processing algorithms. The approach is to use statistics to describe ranges of cardiac behavior that share some common feature with respect to the purpose of the signal processing. The statistical approach has the advantage that, coupled with a statistical performance criterion, it specifies an optimal signal-processing algorithm. These optimal algorithms are often computationally intractable, however, especially for real-time use in instruments. Approximations are therefore crucial. The mathematical form of the model is then important since, even if two forms generate identical statistics, the approximations that are natural in different forms can be quite different. Two different mathematical formulations are described--stochastic Petri nets and interacting Markov chains--and the different types of approximately optimal signal-processing algorithms that are natural in these two frameworks are discussed.

Algorithms↗

PubMed2006

Application of response surface methodology for the biosorption of copper using Rhizopus arrhizus.

Response surface methodology was used to study the cumulative effect of the various parameters namely, initial copper ion concentration, pH, temperature, biomass loading and to optimize the process conditions for the maximum removal of copper. For obtaining the mutual interaction between the variables and optimizing these variables, a 2(4) full factorial central composite design using response surface methodology was employed. The analysis of variance (ANOVA) of the quadratic model demonstrates that the model was highly significant. The model was statistically tested and verified by experimentation. A maximum copper removal of 98% was obtained using the biosorption kinetics of copper under optimum conditions.

Adsorption↗

PubMedDate not supplied

Improving the process quality using statistical design of experiments: a case study.

A technique known as Statistical design of experiments is a powerful technique for process characterization, optimization, and modeling. It has been widely accepted in manufacturing industry for improving product performance and reliability, process capability, and yield. This article illustrates the application of statistical design of experiments based on the Taguchi approach in a certain company that manufactures electromagnetic clutch coils. The objective of the study was to improve the quality of the existing process and thereby achieve heightened customer satisfaction for the product. An eight-trial experiment was conducted with the aim of reducing the number of rejects from the process. The expected savings per month was estimated to be over $11,500. The results of the study have provided a greater stimulus for the wider application of statistical design of experiments in other core processes within the company.

Analysis of Variance↗

PubMed1996

Refusal of treatment, leading to death: towards optimization of informed consent.

Few medical decisions create more anguish than ones involving cessation of treatment, resulting in the death of a patient. In this article, the ethical and legal aspects of the withdrawal of treatment are examined with respect to a case of a 67-year-old man who fell and sustained a fracture of his second cervical vertebra, rendering him paralysed and respirator-dependent. He immediately requested the withdrawal of treatment, but his family baulked. Ethics consultation recommended delaying the decision, to give the patient enough time to foster optimal comprehension and synthesis of information related to his condition and the consequences; we refer to this process as "optimization of informed consent." When the patient was informed of the delay and the reasons for it, he was assured (and subsequently repeatedly reassured) of his ultimate right to refuse treatment at a future date. On balance, optimization of informed consent promotes patients' autonomy, even though it involves suspending this autonomy for a time. It is also consistent with physicians' responsibility to promote life and avoid premature death.

Aged↗

PubMedDate not supplied

Effectiveness of signal processing strategies for the pediatric population: a systematic review of the evidence.

A systematic review of literature addressing the question "Is there evidence pointing to optimal signal processing for pediatric hearing aid patients?" was conducted. Key words and authors were used as search terms in five databases, and one textbook appendix was reviewed for related references. The levels of evidence that were accepted comprised randomized controlled trials, nonrandomized controlled trials, cohort, and before/after designs with or without control groups. Two hundred twenty-six articles were identified during the preliminary search with 183 of these eliminated by review of abstracts because they did not meet the search criteria. Forty-three manuscripts were reviewed, with eight meeting the evidence levels and search criteria. The strengths and weaknesses of these studies are highlighted, and the systematic review question is answered in light of these studies. There is evidence to recommend wide dynamic range compression signal processing for pediatric hearing aid users with mild, moderate, and moderately severe sensorineural hearing loss when full-time and consistent audibility is the goal of the hearing aid fitting. Further, there is evidence that audibility across a wide frequency bandwidth as well as across a large range of input levels is essential for pediatric hearing aid users to recognize critical components of the spoken language.

Adolescent↗

PubMed2003

Modeling interdependencies between business and communication processes in hospitals.

The optimization and redesign of business processes in hospitals is an important challenge for the hospital information management who has to design and implement a suitable HIS architecture. Nevertheless, there are no tools available specializing in modeling information-driven business processes and the consequences on the communication between information processing, tools. Therefore, we will present an approach which facilitates the representation and analysis of business processes and resulting communication processes between application components and their interdependencies. This approach aims not only to visualize those processes, but to also to evaluate if there are weaknesses concerning the information processing infrastructure which hinder the smooth implementation of the business processes.

Commerce↗

PubMed2005

Preparation of polymeric nanocapsules containing octyl methoxycinnamate by the emulsification-diffusion technique: penetration across the stratum corneum.

Polymeric nanocapsules (NCs) containing octyl methoxycinnamate (OMC) as lipophilic molecule were prepared, and their in vivo distribution profile through the stratum corneum (SC) was determined by the tape-stripping technique. Penetration degree of OMC formulated in NCs was compared with that obtained for a nanoemulsion (NE), and a conventional oil-in-water (o/w) emulsion (EM). To produce stable cellulose acetate phthalate (CAP) nanocapsules containing the lipophilic sunscreen, a study was conducted to optimize the process of NC preparation based on the emulsification-diffusion technique. NC formation was verified by measuring their density using differential centrifugation. NC density revealed that an OMC (microL)/CAP (mg) ratio of 2.5:1 is optimal for encapsulation. High encapsulation entrapment (>96%) and excellent process efficiency (recovered quantity of NCs in relation with the initial amount of OMC and CAP >99%) were always achieved with this ratio or a higher one. The capsular structure of the NCs was evidenced with a direct SEM technique. NE was prepared by the emulsification-diffusion technique, dissolving a specific quantity of OMC in water-saturated 2-butanone and then, emulsifying with an aqueous solution of PVAL. In vivo percutaneous penetration, evaluated by the tape-stripping technique, demonstrated that NE increased the extent of OMC penetration relative to the penetration achieved by NCs or EM, with relative penetration depths through the SC of 0.86 +/- 0.1, 0.64 +/- 0.11, and 0.57 +/- 0.08, respectively. In the same manner, the accumulation in the skin of OMC was significantly greater with NE than with EM or NCs. OMC penetration depth was strongly dependent upon the size of the colloidal particles and their flexibility.

Adult↗

PubMed2005

Statistical error in isothermal titration calorimetry: variance function estimation from generalized least squares.

The method of generalized least squares (GLS) is used to assess the variance function for isothermal titration calorimetry (ITC) data collected for the 1:1 complexation of Ba(2+) with 18-crown-6 ether. In the GLS method, the least squares (LS) residuals from the data fit are themselves fitted to a variance function, with iterative adjustment of the weighting function in the data analysis to produce consistency. The data are treated in a pooled fashion, providing 321 fitted residuals from 35 data sets in the final analysis. Heteroscedasticity (nonconstant variance) is clearly indicated. Data error terms proportional to q(i) and q(i)/v are well defined statistically, where q(i) is the heat from the ith injection of titrant and v is the injected volume. The statistical significance of the variance function parameters is confirmed through Monte Carlo calculations that mimic the actual data set. For the data in question, which fall mostly in the range of q(i)=100-2000 microcal, the contributions to the data variance from the terms in q(i)(2) typically exceed the background constant term for q(i)>300 microcal and v<10 microl. Conversely, this means that in reactions with q(i) much less than this, heteroscedasticity is not a significant problem. Accordingly, in such cases the standard unweighted fitting procedures provide reliable results for the key parameters, K and DeltaH(degrees) and their statistical errors. These results also support an important earlier finding: in most ITC work on 1:1 binding processes, the optimal number of injections is 7-10, which is a factor of 3 smaller than the current norm. For high-q reactions, where weighting is needed for optimal LS analysis, tips are given for using the weighting option in the commercial software commonly employed to process ITC data.

Analysis of Variance↗

PubMed1995

The CQI paradigm: a pathway to nurse empowerment in a community hospital.

Anderson Area Medical Center instituted continuous quality improvement (CQI) hospitalwide two years ago. Three teams were challenged with identifying and improving processes related to accounts receivable. X-ray report turn-around-time, and emergency department patient satisfaction. Nursing participation was sought for all three teams. An eight-step CQI process was used to identify, analyze, and improve these three processes. Substantial nursing participation in these pilot CQI teams led to further participation in many other CQI teams optimizing clinical processes. Nursing personnel gained opportunities to make significant contributions to the enhancement of clinical and administrative processes in a large hospital. Nurses learned to work with other members of the health care team outside of their traditional domains, and this, combined with formalized training in the team process, is empowering.

Accounts Payable and Receivable↗

PubMed2004

[Recovery of CO from an ammonia plant tail gas with pressure swing adsorption process].

Ammonia plant tail gas is an important CO source for C1 chemistry if an efficient separation/purification technology is available. Presented is pressure swing adsorption using a home made catalyst PU1 for recovery of CO from ammonia plant tail gas. A performance comparison of PU1 with a commercial zeolite was also presented. The pilot plant experiments were carried out in an intermission one-bed PSA unit with ammonia plant tail gas and a feed flow rate of 0.2-0.8 m3/h. The purity and recovery of CO was studied under various operating conditions. The operating conditions for the process were optimized and an optimum cyclic sequence of operation steps was proposed. A good performance of PU1 in the process was experimentally demonstrated. Product gas with a CO purity over 98% could be produced at a CO recovery of 75% for a feed gas CO concentration of 30% and gas pressure of 0.3 MPa.

Adsorption↗

PubMed2005

[Reparative bone regeneration after aseptic necrosis of the femoral head as influenced by 1-chloromethylsilatrane treatment].

The aim of this work was to study the effect of 1-chloromethyisilatranum on the processes of reparative bone regeneration in experimentally induced aseptic femoral head necrosis. Aseptic femoral head necrosis was modeled in 4 Chinchilla rabbits by destruction of spongy substance of femoral neck and cutting of ligamentum teres of its head. Rabbits of the experimental group were injected with 0.4 ml of 1% solution of 1-chloromethylsilatranum on postoperational days 5, 10, 15 and 20 into the damaged femoral head and close to the damaged joint. Animal were sacrificed by air embolism 5 weeks from the start of an experiment. Necrotic and repair processes in hip joints from damaged and intact sides were assessed radiologically and histologically prior to sacrifice. In rabbits of both control and experimental groups extensive aseptic necrosis of hip joints was found. The osseous tissue of damaged hip joints of experimental animals contained the chains of osteoblasts actively producing new bone matrix. Foci of bone regeneration were found both in the deep and peripheral regions of the epiphysis, which is indicative of active processes of bone repair. The results obtained suggest that administration of organic-silicon drug 1-chloromethylsilatranum stimulates (optimizes) the processes of repair osteogenesis following aseptic femoral head necrosis in experimental animals. Application of this preparation appears to be very promising.

Animals↗

PubMed2004

Process and formulation variables affecting the performance of a rupturable capsule-based drug delivery system with pulsatile drug release.

The objective of this study was to optimize several process and formulation parameters, which influence the performance of a rupturable, pulsatile drug delivery system. The system consisted of a drug-containing hard gelatin capsule, a swelling layer of croscarmellose (Ac-Di-Sol) and a binder, and an outer ethylcellulose coating. Polyvinyl pyrrolidone (Kollidon 90F) was superior to HPMC and HPC as a binder for the swelling layer with regard to binding (adherence to capsule) and disintegration properties of the swelling layer. The capsule-to-capsule uniformity in the amount of swelling layer and outer ethylcellulose coating, which significantly affected the lag time prior to rupture of the capsule, was optimized by decreasing the batch size, and by increasing the rotational pan speed and the distance between the spray nozzle and the product bed. The type of baffles used in the coating pan also affected the layering uniformity. Fully-filled hard gelatin capsules had a shorter lag time with a higher reproducibility compared to only half-filled capsules, because the swelling pressure was directed primarily to the outer ethylcellulose coating and not to the inner capsule core. Stability studies revealed that the lag time of the capsules was stable over a 240-day period when the moisture content was kept unchanged.

Capsules↗

PubMedDate not supplied

Optimization of a fluid bed spray coating process using reduced factorial design.

A sequential approach to the optimization of a fluid bed coating process of pellets for controlled release using organic solvents and ethylcellulose has been applied using reduced factorial experiments. The optimization was started by applying a 2(4-1) experiment then, based on the results from that study, further experiments were carried out where only the variables which had the most significant effect on the film yield were used. Finally, a 2(3-1) experiment was performed. A relationship was found between the film yield and degree of agglomeration, indicating a limiting value of the film yield (75 per cent) below which only little agglomeration takes place. Above this value, the degree of agglomeration increases dramatically. The limit value was found to change only to a minor extent as a function of experimental conditions.

Delayed-Action Preparations↗

PubMed1997

Optimization of aqueous-based film coating of tablets performed by a side-vented pan-coating system.

The purpose of this research was to characterize the aqueous-based hydroxypropylmethylcellulose (HPMC) film coating of tablets utilizing a laboratory-scale side-vented pan-coating apparatus (Thai coater). The process and apparatus parameters of potential importance with respect to the final film quality were evaluated by using fractional factorial design (2(6-2)IV) and the process was optimized using response surface methodology (central composite design). Rotating speed of the pan was identified as a major parameter with respect to film thickness (weight increase; p < 0.05) and breaking strength (p < 0.05) of the aqueous HPMC film-coated tablets. Increasing the rotating speed from 5 rpm to 10 rpm resulted in a mean relative change of -43.9% and 2.4% of film thickness (weight increase) and breaking strength, respectively. As expected, inlet air temperature significantly affected the moisture content of the final film-coated tablets (p < 0.01) and the film thickness (weight increase; p < 0.05), but the effects on the other responses studied were minimal or negligible. Pneumatic spraying pressure and position of the spray gun (excluding angle of the gun) did not affect the responses studied. The process parameters relevant to a side-vented pan-coating process can be identified (by fractional factorial design) and, consequently, optimized (by central composite design) by using the factorial design approach.

Chemistry, Pharmaceutical↗

PubMed2004

Effect of feed and bleed rate on hybridoma cells in an acoustic perfusion bioreactor: part I. Cell density, viability, and cell-cycle distribution.

For the development of optimal perfusion processes the effect of the feed and bleed rate on cell growth in a perfusion bioreactor was studied. The viable-cell density, viability, growth, death, and lysis rate and cell-cycle distribution of a hybridoma cell line producing an IgG1 were studied over a range of specific feed and bleed rates. It was found that the feed and bleed rates applied in the different cultures could be divided into two regions based on the viable-cell density and cell-cycle distribution. The cultures in the first region, low feed rates (0.5 and 1.0 d(-1)) combined with low bleed rates (0.05 and 0.10 d(-1)), were nutrient-limited, as an increase in the feed rate resulted in an increase in the viable-cell density. The cultures in the second region, high feed and bleed rates, were nonnutrient-limited. In this region the viable-cell density decreased more or less linearly with an increase in the bleed rate and was independent of the feed rate. This suggests that the cells were limited by a cell-related factor. Comparison of Trypan-blue dye-exclusion measurements and lactate-dehydrogenase activity measurements revealed that cell lysis was not negligible in this bioreactor set-up. Therefore, lactate-dehydrogenase activity measurements were essential to measure the death rate accurately. The specific growth rate was nearly constant for all tested conditions. The viability increased with an increase of the bleed rate and was independent of the feed rate. Furthermore, the specific productivity of monoclonal antibody was constant under all tested conditions. For the optimal design of a perfusion process it should first be established whether viability is an important parameter. If not, a bleed rate as low as possible should be chosen. If low viabilities are to be avoided, the bleed rate chosen should be higher, with the value depending on the desired viability. Next, the feed rate should be set at such a rate that the cells are just in the nonnutrient-limited region.

Acoustics↗

PubMed2006

Axillary endoscopic breast augmentation: processes derived from a 28-year experience to optimize outcomes.

BACKGROUND: The axillary approach for breast augmentation has been an option for patients and surgeons for three decades. This article reports a 28-year experience with axillary subpectoral and submammary breast augmentation, and defines proved processes and surgical techniques that have evolved during that experience. METHODS: From 1977 to 2005, 690 patients aged 19 to 64 years (median age, 31 years) chose the axillary augmentation approach for breast augmentation. Eighty-four patients had implants placed in the retromammary pocket location, 294 patients had partial retropectoral placement, and 312 patients had dual plane placement. Preoperative planning and implant selection after 1993 utilized dimensional and tissue-based processes published in this Journal. RESULTS: Using optimal published processes and instrumentation via the axillary approach, surgeons can deliver equally aesthetic results with equal recovery, reoperation rates, and complications compared with every other incision approach. Refinements in surgical techniques and instrumentation enable patients to predictably experience 24-hour return to normal activities after axillary subpectoral or submammary augmentation. CONCLUSIONS: The axillary incision approach for retromammary, partial retropectoral, and dual plane augmentation is an option for patients and surgeons who wish to locate the incision off the breast. Optimal outcomes and 24-hour recovery require a specific surgeon skill set, dimension and tissue-based preoperative planning, and implant selection, defining the desired level of the inframammary fold using proved processes and optimal instrumentation and minimizing tissue trauma and bleeding by implementing proved processes described in this article.

Adult↗