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1.
Sci Rep ; 10(1): 7914, 2020 05 13.
Article in English | MEDLINE | ID: mdl-32404933

ABSTRACT

Freeze casting has emerged as one of the most promising manufacturing methods to fabricate porous scaffolds in recent years. This is due to various reasons which include a wide range of materials which can be used in this process, easiness of the process, etc. One of the major objectives of this work was to fabricate bone-like structure by using a modified freeze casting process. In this work, Hydroxyapatite and Tricalcium phosphate scaffolds with bone-like structure were fabricated by understanding and utilizing the basic physics of freeze casting. Thermal conductivity of the base plate is a crucial factor for obtaining controlled pore and porosity distribution in a porous scaffold. It was found that designing the base plate with variable thermal conductivity has led to the formation of bone-like structure. Porous scaffolds were quantitatively analyzed for pore size and porosity distribution at center and circumference. Porosity at circumference was observed to be approximately dropped by 55%, a similar trend was seen for pore size. Therefore, it was significant evidence that modified freeze casting has capable in fabricating bone-like structures with ease and good control. This will open many new applications of porous scaffolds in biomedical, energy devices, chemical catalyst and many more.

2.
J Mech Behav Biomed Mater ; 79: 189-194, 2018 03.
Article in English | MEDLINE | ID: mdl-29306082

ABSTRACT

The long standing need of the implant manufacturing industries is to fabricate multi-matrix, customized porous scaffold as cost-effectively. In recent years, freeze casting has shown greater opportunity in the fabrication of porous scaffolds (tricalcium phosphate, hydroxyapatite, bioglass, alumina, etc.) such as at ease and good control over pore size, porosity, a range of materials and economic feasibility. In particular, tricalcium phosphate (TCP) has proved as it possesses good biocompatible (osteoinduction, osteoconduction, etc.) and biodegradability hence beta-tricalcium phosphate (ß-TCP, particle size of 10µm) was used as base material and camphene was used as a freezing vehicle in this study. Both freezing conditions such as constant freezing temperature (CFT) and constant freezing rate (CFR) were used for six different conditional samples (CFT: 30, 35 and 40vol% solid loading; similarly CFR: 30, 35 and 40vol% solid loading) to study and understand the effect of various properties (pore size, porosity and compressive strength) of the freeze-cast porous scaffold. It was observed that the average size of the pore was varying linearly as from lower to higher when the solid loading was varying higher to lower. With the help of scanning electron micrographs (SEM), it was observed that the average size of pore during CFR (9.7/ 6.5/ 4.9µm) was comparatively higher than the process of CFT (6.0/ 4.8/ 2.6µm) with respect to the same solid loading (30/ 35/ 40vol%) conditions. From the Gas pycnometer analysis, it was found that the porosity in both freezing conditions (CFT, CFR) were almost near values such as 32.8% and 28.5%. Further to be observed that with the increase in solid loading, the total porosity value has decreased due to the reduction in the concentration of the freezing vehicle. Hence, the freezing vehicle was found as responsible for the formation of appropriate size and orientation of pores during freeze casting. The compressive strength (CS) testing was clearly indicated that the CS was majorly depending on the size of pore which was depending on solid loading. The CS of CFT-based samples (smaller pore sizes and higher resistance to the propagation of crack) were higher due to the higher solid content (pore size) in compared with CFR-based samples on the similar solid loading conditions. As evidently, it was noted that the CFT-based sample with 40% solid loading has given the compressive strength which has come in the range of cancellous bone. The positive note was that the ratio of Ca/P has come as 1.68 (natural bone) after sintering and that was the required value recommended by the food and drug administration (FDI) for manufacturing of bone implants.


Subject(s)
Bone Substitutes/chemistry , Calcium Phosphates/chemistry , Freezing , Terpenes/chemistry , Bicyclic Monoterpenes , Particle Size , Temperature
3.
Hawaii J Med Public Health ; 76(10): 275-278, 2017 10.
Article in English | MEDLINE | ID: mdl-29018589

ABSTRACT

In recent times, there has been an increased focus on mosquito-borne Flaviviruses, in particular dengue and Zika. With the reappearance of dengue in Hawai'i and the mainland United States (US), clinicians should be aware of both the common presentations of dengue, as well as other less common complications associated with the disease. Dengue can result in neurologic disorders such as encephalopathy, encephalitis, immune-mediated syndromes, neuromuscular dysfunction, and neuro-ophthalmologic disorders. We present an interesting case of dengue that initially presented with classic symptoms (arthropathy, biphasic fever, and rash) and subsequently developed into a neurologic movement disorder with muscle tightening and twitching of the face, chest, and extremities. We review and update the epidemiology, biology, the clinical presentations including the neurologic complications associated with dengue, as well as their management and areas of future study in this field.


Subject(s)
Dengue/complications , Nervous System Diseases/etiology , Adult , Chills/etiology , Diarrhea/etiology , Female , Flavivirus/pathogenicity , Hawaii , Humans , Nausea/etiology , Polynesia/ethnology , Travel-Related Illness , Water Sports
4.
Chem Eng J ; 260: 801-808, 2015 Jan 15.
Article in English | MEDLINE | ID: mdl-32288624

ABSTRACT

Hybrid hydrophobic composite PVDF-Ag-Al2O3 nanofibrous air filtration membranes are synthesized by the electrospinning method with different concentrations of Al2O3 and fixed concentration of Ag to study their antibacterial, particulate filtration efficiencies, and their detoxification ability. All the membranes were characterized for their physical and chemical properties before being tested. It was also found that at Al2O3 concentrations higher than 8%, nanofibers could not be formed by the pure blending and electrospinning technique. The antibacterial activity of the membranes proved that silver incorporation provided suitable disinfection with greater than 99.5% antibacterial efficiency for all membranes. The antibacterial efficiency of the membranes was maintained even as the concentration of Al2O3 was increased. The hydrolysis of paraoxon, a nerve agent simulant, for the prepared membranes was also studied. The removal of paraoxon was found to increase as the loaded concentration of Al2O3 in the membrane increased. The particulate filtration efficiency of the prepared membranes was tested using particles of diameter 0.36 µm. Compared to the nascent PVDF nanofiber membranes with particle filtration efficiency of 94%, the Ag and Al2O3 loaded membranes all had a higher particle filtration efficiency. Interestingly, it was found that as the concentration of Al2O3 loaded in the membranes increased so did the particle filtration efficiency. Membrane characterization data revealed that as the concentration of the Al2O3 was increased, the average pore size of the membrane was reduced and the thickness of the filter mat increased. This would explain the higher retention of the particles by these filters. Correspondingly, the resistance of the filters also increased as more Al2O3 was loaded in the nanofiber membranes. The synthesized nanofibrous membranes have the potential to be used as 3 in 1 highly efficient air filters.

6.
J Patient Saf ; 10(1): 20-8, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24553441

ABSTRACT

OBJECTIVES: Testing plays a vital role in primary care. Failures in the process are common and can be harmful. As the great 19th century microbiologist Louis Pasteur put it "chance favors only the prepared mind." Our objective is to prepare minds in primary care practices to improve safety in the testing process. Various principles from safety science can be applied. METHODS: A prospective methodology that uses an anonymous practice survey based on concepts from failure modes and effects analysis is proposed. Responses are used to rank perceived hazards in the testing process, leading to prioritization of areas for intervention. Secondary data analysis (using data from a study of medication safety) was used to explore the value of this approach in the context of assessing the testing process. RESULTS: At 3 primary care practice sites, a total of 61 staff members completed 4 survey items examining the testing process. Comparison across practices shows that each has a distinct profile of hazards, which would lead each on a different path toward improvement. DISCUSSION: The proposed approach treats each practice as a unique complex adaptive system aiming to help it thrive by inculcating trust, mutual respect, and collaboration. Implications for patient safety research and practice are discussed.


Subject(s)
Diagnostic Tests, Routine/methods , Medical Errors/prevention & control , Patient Safety , Primary Health Care/organization & administration , Adult , Cognitive Dissonance , Female , Humans , Male , Middle Aged , Monitoring, Physiologic/methods , Physicians' Offices/organization & administration , Prospective Studies
7.
J Am Med Inform Assoc ; 21(4): 671-8, 2014.
Article in English | MEDLINE | ID: mdl-24287171

ABSTRACT

BACKGROUND AND OBJECTIVE: We postulate that professional proximity due to common patients and geographical proximity among practice locations are significant factors influencing the adoption of health information exchange (HIE) services by healthcare providers. The objective of this study is to investigate the direct and indirect network effects of these drivers on HIE diffusion. DESIGN: Multi-dimensional scaling and clustering are first used to create different clusters of physicians based on their professional and geographical proximities. Extending the Bass diffusion model to capture direct and indirect network effects among groups, the growth of HIE among these clusters is modeled and studied. The network effects among the clusters are investigated using adoption data over a 3-year period for an HIE based in Western New York. MEASUREMENT: HIE adoption parameters-external sources of influence as well as direct and indirect network coefficients-are estimated by the extended version of the Bass diffusion model. RESULTS: Direct network effects caused by common patients among physicians are much more influential on HIE adoption as compared with previously investigated social contagion and external factors. Professional proximity due to common patients does influence adoption decisions; geographical proximity is also influential, but its effect is more on rural than urban physicians. CONCLUSIONS: Flow of patients among different groups of physicians is a powerful factor in HIE adoption. Rather than merely following the market trend, physicians appear to be influenced by other physicians with whom they interact with and have common patients.


Subject(s)
Computer Communication Networks , Electronic Health Records/organization & administration , Geography, Medical , Information Dissemination , Humans , Medical Record Linkage
8.
Adv Med Educ Pract ; 4: 231-6, 2013.
Article in English | MEDLINE | ID: mdl-24235855

ABSTRACT

The introduction of health information technology (HIT) can have unexpected and unintended patient safety and/or quality consequences. This highly desirable but complex intervention requires workflow changes in order to be effective. Workflow is often cited by providers as the number one 'pain point'. Its redesign needs to be tailored to the organizational context, current workflow, HIT system being introduced, and the resources available. Primary care practices lack the required expertise and need external assistance. Unfortunately, the current methods of using esoteric charts or software are alien to health care workers and are, therefore, perceived to be barriers. Most importantly and ironically, these do not readily educate or enable staff to inculcate a common vision, ownership, and empowerment among all stakeholders. These attributes are necessary for creating highly reliable organizations. We present a tool that addresses US Accreditation Council for Graduate Medical (ACGME) competency requirements. Of the six competencies called for by the ACGME, the two that this tool particularly addresses are 'system-based practice' and 'practice-based learning and continuing improvement'. This toolkit is founded on a systems engineering approach. It includes a motivational and orientation presentation, 128 magnetic pictorial and write-erase icons of 40 designs, dry-erase magnetic board, and five visual aids for reducing cognitive and emotive biases in staff. Pilot tests were carried out in practices in Western New York and Colorado, USA. In addition, the toolkit was presented at the 2011 North American Primary Care Research Group (NAPCRG) meeting and an Agency for Health Research and Quality (AHRQ) meeting in 2013 to solicit responses from attendees. It was also presented to the officers of the Office of the National Coordinator (ONC) for HIT. All qualitative feedback was extremely positive and enthusiastic. The respondents recommended that the toolkit be disseminated widely to improve staff education and training, leading to practice improvements.

10.
Bioresour Technol ; 117: 80-5, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22609717

ABSTRACT

This paper explores the use of a novel microalgae membrane photoreactor (mMR) to polish the effluent from an aerobic membrane bioreactor (MBR) fed with domestic wastewater. Four microalgae species Chlorella (Chlorella sp.), Chlorella vulgaris (C. vulgaris), Scenedesmus quadricauda (S. quadricauda) and Scenedesmus dimorphus (S. dimorphus) were isolated from the environment and tested in batch reactors fed with permeate from the aerobic MBR to evaluate the nutrient removal rates for each species. All four microalgae species were able to completely remove NH4 in the reactor within 3 days. The removal rates of NO3, NO2 and PO4 were between 43-54%, 83-95% and 70-92%, respectively after 3 days in the batch reactor. Subsequently, an MBR-mMR system was operated for 23 days. The mMR was able to remove on average 50% of NH4, 75% of NO2, 35% of NO3 and 60% of PO4 consistently from the MBR effluent under the conditions tested.


Subject(s)
Membranes, Artificial , Microalgae/metabolism , Nitrogen/isolation & purification , Phosphorus/isolation & purification , Photobioreactors/microbiology , Batch Cell Culture Techniques , Biodegradation, Environmental , Chlorella/growth & development , Microalgae/growth & development , Microalgae/isolation & purification , Nitrates/isolation & purification , Nitrites/isolation & purification , Permeability , Phosphates/isolation & purification , Scenedesmus/growth & development , Time Factors , Waste Disposal, Fluid
11.
Fam Med ; 44(4): 252-8, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22481154

ABSTRACT

BACKGROUND AND OBJECTIVES: Data are limited on order completion errors in primary care. The objective of this study was to determine the incidence and nature of order completion errors among community-dwelling older adults. METHODS: This prospective, cross-sectional exploratory study was conducted at a suburban family medicine clinical teaching site. Patients ?70 years old who received ?one order at the study enrollment visit were eligible for inclusion. Errors in completion of orders for prescriptions, laboratory tests, imaging studies or screening procedures, and specialist referrals were assessed. Logistic regression was used to identify the independent variables associated with non-system-based errors. RESULTS: A total of 322 orders were written for 93 enrolled patients. An order error was identified in 59 (18.3%) orders written for 39 (41.9%) patients (mean 1.5, range 1--4, SD=0.85): 10 were system-based and 49 were non-system-based errors. Non-system-based errors included unfilled prescriptions (9.0%), uncompleted orders for imaging studies and screening procedures (13.0%), and uncompleted specialist referrals (17.4%). All laboratory orders were completed. In a logistic regression model, females were four times more likely to experience a non-system-based error than males (OR=4.02, 95% CI=1.43, 11.23). CONCLUSIONS: Order completion errors were common in this sample of community-dwelling older adults, with non-system-based errors for prescriptions, imaging studies or screening procedures, and specialist referrals occurring more frequently than system-based errors, particularly among females. Providers should not assume that patients will complete orders as intended; rather, longitudinal management requires regular patient follow-up and review to ensure order completion.


Subject(s)
Medical Errors/statistics & numerical data , Patient Compliance/statistics & numerical data , Primary Health Care/statistics & numerical data , Aged , Aged, 80 and over , Chronic Disease/therapy , Cross-Sectional Studies , Female , Humans , Logistic Models , Male , Patients , Prospective Studies , Sex Factors
12.
Int J Family Med ; 2012: 374639, 2012.
Article in English | MEDLINE | ID: mdl-22518306

ABSTRACT

Background. Most safety issues in primary care arise from adverse drug events. Team Resource Management intervention was developed to identify systemic safety issues to design and implement interventions to address prioritized issues. Objectives. Evaluate impact of intervention on rates of events and preventable events in a vulnerable population. Design. Cluster randomized trial. 12 practices randomly assigned to either: (1) Intervention; (2) Intervention with Practice Enhancement Assistants; (3) No intervention. The intervention took 12 months. Main Outcome Measure. Rate and severity of events and preventable events measured using a Trigger Tool chart review method for the 12-month periods before and after the start of the intervention. Results. In the ''intervention with Assistants" group there was a statistically significant decrease in the overall rate of events and in the rate of moderate/severe events. Analysis of Variance with study arm and time as the factors and moderate/severe events as the outcome showed a significant interaction between arm and time supporting the notion that the ''Intervention with Assistants" practices had a greater reduction in moderate/severe preventable events. Conclusions. The intervention had a significant effect on medication safety as estimated using a trigger tool. Further exploration of role of Assistants and trigger tool is warranted.

13.
Am J Manag Care ; 18(3): 169-75, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22435910

ABSTRACT

OBJECTIVES: To develop and pilot-test a Web-based implementation of a team resource management (TRM) intervention to improve medication safety in primary care. STUDY DESIGN: Randomized controlled trial. METHODS: Eight practices were randomized to either the Web-based TRM or usual practice (4 practices in each group). Primary outcome was adverse drug events (ADEs) in older adults, ascertained using a trigger tool chart review at two 12-month periods (before and after the intervention). The prospective TRM approach, designed to inculcate ownership and empowerment, facilitates systematic appraisal of risk and error reduction. This approach uses the highly adaptable and transferable Safety Enhancement and Monitoring Instrument that is Patient Centered. RESULTS: The rate of ADEs decreased from 25.8 to 18.3 per 100 patients per year in the intervention group. The rate was virtually unchanged in the control group (24.3 vs 24.8). In an analysis of covariance at the practice level, being in the intervention group was associated with a lower rate of ADEs. The interaction between time (preintervention vs postintervention) and group (intervention vs control) was not signifi cant (P = .104) but showed a trend toward a decrease in the intervention group compared with the control group over time. CONCLUSIONS: The Web-based TRM intervention proved feasible and demonstrated potential for effectiveness in various ambulatory settings. This pilot study was limited by small size and short follow-up period. Future studies should test the intervention on a larger scale over a longer period of time and should explore methods for overcoming common barriers to change.


Subject(s)
Drug-Related Side Effects and Adverse Reactions/prevention & control , Hospital Information Systems/statistics & numerical data , Medication Errors/prevention & control , Program Evaluation , Quality of Health Care/statistics & numerical data , Systems Analysis , Analysis of Variance , Health Care Surveys , Hospital Information Systems/standards , Humans , Online Systems , Pilot Projects , Program Development , Quality of Health Care/standards , Statistics as Topic , United States
14.
J Biomater Sci Polym Ed ; 23(18): 2337-52, 2012.
Article in English | MEDLINE | ID: mdl-22244047

ABSTRACT

Silver nanoparticles (AgNPs) and silver ions (Ag(+)) show growth-inhibitory activity against microorganisms and have been used for decades as antibacterial agents in various fields. To fabricate a nanofibrous scaffold which is antibacterial against bacteria and non-toxic to cells, we electrospun composite poly(L-lactic acid)-co-poly(ϵ-caprolactone) nanofibres containing silver nanoparticles (PLLCL-AgNPs) with different concentrations (0.25, 0.50 and 0.75 wt%) of silver nitrate (AgNO3) in PLLCL. The diameters of the electrospun PLLCL-AgNPs nanofibres decreased with the increase of AgNO3 concentration in PLLCL solutions. Human skin fibroblasts cultured on the scaffolds showed that the PLLCL nanofibres containing lesser amounts of AgNPs (0.25 wt%) had better cell proliferation and retained the cell morphology similar to the phenotype observed on tissue culture plates (control). The antibacterial activity of AgNPs in PLLCL nanofibres was investigated against Staphylococcus aureus and Salmonella enterica and the antimicrobial activity was found to increase with the increasing concentration of nanoparticles present in the scaffold. Based on our studies, we propose that PLLCL nanofibres containing 0.25 wt% AgNO3 or PLLCL-Ag(25), favors cell proliferation and inhibits bacteria and could be a suitable substrate for wound healing.


Subject(s)
Electricity , Nanofibers/chemistry , Nanotechnology , Polyesters/chemistry , Silver/chemistry , Skin/drug effects , Tissue Engineering/methods , Actins/metabolism , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology , Cell Proliferation/drug effects , Fibroblasts/cytology , Fibroblasts/drug effects , Humans , Metal Nanoparticles/chemistry , Salmonella enterica/drug effects , Silver Nitrate/chemistry , Skin/cytology , Staphylococcus aureus/drug effects , Tissue Scaffolds/chemistry , Wound Healing/drug effects
15.
JRSM Short Rep ; 2(2): 6, 2011 Feb 03.
Article in English | MEDLINE | ID: mdl-21369524

ABSTRACT

OBJECTIVE: To develop a 'Transitions Journal' for inter-unit and inter-setting communication for improving quality and safety of care and patient satisfaction with timely, reliable and meaningful information for all stakeholders. DESIGN: Front-line staff were targeted in a series of four team meetings through which this 'Journal' was developed iteratively; initially as a paper-based and subsequently as an IT-based tool. Goals were to: (1) develop a standardized tool based on SBAR format (Situation, Background, Assessment, Recommendation); (2) facilitate improved communication at the points of care; (3) use a bottom-up approach; (4) create situational awareness and facilitate team formation; and (5) create visual workflow models to help inculcate a culture of safety. SETTING: A 183-bed community-hospital and its Primary Care Center, in an urban area in western New York State. PARTICIPANTS: Ten nurses and 12 physicians representing both the hospital and primary care center participated voluntarily. MAIN OUTCOME MEASURES: (1) Successful development of the 'Transitions Journal'; and (2) identification of its potential uses. RESULTS: (1) DEVELOPMENT: the journal was successfully developed in both paper and web-based formats; (2) identification of uses: participants recommended using the tool as a checklist to verify appropriate communication at both the sending and receiving ends; as an audit tool for retrospective review of handoffs; and as a teaching tool. CONCLUSIONS: A journal developed by and for front-line staff has the potential to provide opportunities for improvement, instill a systems approach, improve care continuity, improve compliance with safety goals, improve patient and staff satisfaction, reduce duplication and costs, inculcate teamwork, and provide mutual emotional and intellectual support. Further work to evaluate and disseminate this tool is in progress.

16.
Teach Learn Med ; 22(4): 287-92, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20936576

ABSTRACT

BACKGROUND: Prescribing nonsteroidal anti-inflammatory drugs (NSAIDs) for older adults is a safety concern. Education innovations in postgraduate training designed to improve patient safety should comply with the Accreditation Council for Graduate Medical Education (ACGME). PURPOSE: The objective is to evaluate a seven-component education program for internal medicine trainees designed to change prescribing practices while addressing ACGME competencies. METHODS: Pretest, posttest data collection. RESULTS: The baseline chart review found that 28.7% (79/275) patients age 70 or older were prescribed NSAIDs. Approximately 1 year later, the proportion of patients prescribed NSAIDs had declined to 16.4% (30/183; p= .002). The proportion of patients prescribed NSAIDs in conjunction with a diuretic similarly declined from 13.6% (38/278) to 7% (13/187; p= .024). CONCLUSION: A systematically applied education program targeted to a specific prescribing pattern produced significant improvement among internal medicine trainees. This model may assist training programs in reducing polypharmacy, or in other areas of trainee practice.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal , Internal Medicine/education , Polypharmacy , Practice Patterns, Physicians'/standards , Quality of Health Care , Age Factors , Aged , Algorithms , Education, Medical, Graduate , Educational Measurement , Educational Status , Female , Humans , Male , Patient Care , Problem-Based Learning , Program Development , Program Evaluation , Retrospective Studies , Safety
17.
J Patient Saf ; 5(2): 55-60, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19920441

ABSTRACT

OBJECTIVES: There are international calls for improving education for health care workers around certain core competencies, of which patient safety and quality are integral and transcendent parts. Although relevant teaching programs have been developed, little is known about how best to assess their effectiveness. The objective of this work was to develop and implement an objective structured clinical examination (OSCE) to evaluate the impact of a patient safety curriculum. METHODS: The curriculum was implemented in a family medicine residency program with 47 trainees. Two years after commencing the curriculum, a patient safety OSCE was developed and administered at this program and, for comparison purposes, to incoming residents at the same program and to residents at a neighboring residency program. RESULTS: All 47 residents exposed to the training, all 16 incoming residents, and 10 of 12 residents at the neighboring program participated in the OSCE. In a standardized patient case, error detection and error disclosure skills were better among trained residents. In a chart-based case, trained residents showed better performance in identifying deficiencies in care and described more appropriate means of addressing them. Third year residents exposed to a "Systems Approach" course performed better at system analysis and identifying system-based solutions after the course than before. CONCLUSIONS: Results suggest increased systems thinking and inculcation of a culture of safety among residents exposed to a patient safety curriculum. The main weaknesses of the study are its small size and suboptimal design. Much further investigation is needed into the effectiveness of patient safety curricula.


Subject(s)
Curriculum , Family Practice/education , Internship and Residency , Safety Management , Humans , Teaching/methods
18.
Water Res ; 42(3): 707-13, 2008 Feb.
Article in English | MEDLINE | ID: mdl-17709127

ABSTRACT

Although acidification of feed water is a common practice to prevent scaling of the sparingly soluble minerals in nanofiltration and reverse osmosis processes, the change of acidity may have a potentially adverse impact on colloidal fouling, which is another important type of fouling on the membranes. In this paper, commonly used strong and weak acids are quantitatively investigated for their effect on colloidal silica fouling with a lab-scale ultrafiltration (UF) membrane system. Experiments showed that addition of either strong or weak acids in feed water would intensify colloidal fouling. However, the strength of colloidal fouling with strong acid addition was consistently higher (12-37%) than that with weak acid addition at pH 3. The smaller increase in colloidal fouling potential observed with weak acids was attributed to the adsorption of weak acid anions on the colloidal silica surface, which kept the absolute value of zeta potential of the colloids relatively high. Consequently, the difference in colloidal fouling potential with the additions of strong and weak acids diminished at high salt concentration. The findings implied that the type of acid used in feed water acidification could have a significant impact on colloidal fouling for low-salinity waters.


Subject(s)
Acids, Noncarboxylic/chemistry , Silicon Dioxide/chemistry , Water Purification/instrumentation , Colloids , Equipment Failure Analysis , Hydrogen-Ion Concentration , Osmolar Concentration , Ultrafiltration/instrumentation , Waste Disposal, Fluid/instrumentation
19.
Langmuir ; 23(26): 13085-92, 2007 Dec 18.
Article in English | MEDLINE | ID: mdl-18004889

ABSTRACT

Electrospun nanofibrous membranes (ENM) which have a porous structure have a huge potential for various liquid filtration applications. In this paper, we explore the viability of using plasma-induced graft copolymerization to reduce the pore sizes of ENMs. Poly(vinylidene) fluoride (PVDF) was electrospun to produce a nonwoven membrane, comprised of nanofibers with diameters in the range of 200-600 nm. The surface of the ENM was exposed to argon plasma and subsequently graft-copolymerized with methacrylic acid. The effect of plasma exposure time on grafting was studied for both the ENM and a commercial hydrophobic PVDF (HVHP) membrane. The grafting density was quantitatively measured with toluidine blue-O. The degree of grafting increased steeply with an increase in plasma exposure time for the ENM, attaining a maximum of 180 nmol/mg after 120 s of plasma treatment. However, the increase in the grafting density on the surface of the HVHP membrane was not as drastic, reaching a plateau of 65 nmol/mg after 60 s. The liquid entry permeation of water dropped extensively for both membranes, indicating a change in surface properties. Field emission scanning electron microscopy micrographs revealed an alteration in the surface pore structure for both membranes after grafting. Bubble point measurements of the ENM reduced from 3.6 to 0.9 um after grafting. The pore-size distribution obtained using the capillary flow porometer for the grafted ENM revealed that it had a similar profile to that of a commercial hydrophilic commercial PVDF (HVLP) membrane. More significantly, water filtration studies revealed that the grafted ENM had a better flux throughput than the HVLP membrane. This suggests that ENMs can be successfully engineered through surface modification to achieve smaller pores while retaining their high flux performance.


Subject(s)
Membranes, Artificial , Nanostructures , Polymethacrylic Acids/chemistry , Polyvinyls/chemistry , Spectroscopy, Fourier Transform Infrared , Surface Properties
20.
Geriatr Nurs ; 28(2): 126-36, 2007.
Article in English | MEDLINE | ID: mdl-17430747

ABSTRACT

Safety has not been well studied in the long-term care setting. This pilot study assesses staff attitudes regarding safety culture at one 250-bed skilled nursing facility. A valid and reliable Safety Attitudes Questionnaire (SAQ) was administered once to a sample of 51 employees. Nursing staff and other health care staff were generally satisfied with their jobs (42% and 67% had a positive attitude, respectively) but gave low scores to Management (22% and 13%, respectively) and Safety Climate (28% and 33%, respectively). Registered nurses, licensed practical nurses, and nurse management/supervisors received the highest ratings for quality of collaboration and communication (range: 3.6-4.1 on a 5-point Likert scale with 1 = very low, 5 = very high), whereas nurse practitioners and physician assistants received the lowest (range: 2.5-2.9). The SAQ provided insight into employees' safety attitudes and can be used to identify opportunities for improvements in safety.


Subject(s)
Attitude of Health Personnel , Health Personnel/psychology , Safety Management , Skilled Nursing Facilities , Clinical Competence/standards , Communication , Cooperative Behavior , Female , Health Knowledge, Attitudes, Practice , Health Personnel/education , Health Services Needs and Demand , Humans , Interprofessional Relations , Job Satisfaction , Male , New York , Nurse Administrators/education , Nurse Administrators/psychology , Nurse Practitioners/education , Nurse Practitioners/psychology , Nursing Assistants/education , Nursing Assistants/psychology , Nursing Methodology Research , Nursing Staff/education , Nursing Staff/psychology , Nursing, Practical/education , Nursing, Practical/organization & administration , Organizational Culture , Physician Assistants/education , Physician Assistants/psychology , Pilot Projects , Safety Management/organization & administration , Skilled Nursing Facilities/organization & administration , Surveys and Questionnaires
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