Loss Of Physical Integrity Research Articles

Bacteria-Polymer Composite Material for Glycerol Valorization.

Bacterial immobilization is regarded as an enabling technology to improve the stability and reusability of biocatalysts. Natural polymers are often used as immobilization matrices but present certain drawbacks, such as biocatalyst leakage and loss of physical integrity upon utilization in bioprocesses. Herein, we prepared a hybrid polymeric matrix that included silica nanoparticles for the unprecedented immobilization of the industrially relevant Gluconobacter frateurii (Gfr). This biocatalyst can valorize glycerol, an abundant by-product of the biodiesel industry, into glyceric acid (GA) and dihydroxyacetone (DHA). Different concentrations of siliceous nanosized materials, such as biomimetic Si nanoparticles (SiNps) and montmorillonite (MT), were added to alginate. These hybrid materials were significantly more resistant by texture analysis and presented a more compact structure as seen by scanning electron microscopy. The preparation including 4% alginate with 4% SiNps proved to be the most resistant material, with a homogeneous distribution of the biocatalyst in the beads as seen by confocal microscopy using a fluorescent mutant of Gfr. It produced the highest amounts of GA and DHA and could be reused for up to eight consecutive 24 h reactions with no loss of physical integrity and negligible bacterial leakage. Overall, our results indicate a new approach to generating biocatalysts using hybrid biopolymer supports.

Quality of Life of Patients With Major Amputations in the Tertiary Care Center of Western Rajasthan: A Prospective Observational Study in 2019-2020.

IntroductionAmputation of a limb is a loss of physical integrity that has disastrous consequences for a person's mental, physical, and social well-being.AimWe aim to analyze the quality of life (QoL) after major amputations and long-term outcomes.Method and materialsA prospective, observational study has been conducted in a health care institute in western Rajasthan from January 2019 to July 2020. This study included 64 patients who had major upper or lower limb amputations. We analyzed the sociodemographic factors of the patients, the type of procedure, postoperative hospital stay, complications, and follow-up status with both the SF-12 and the World Health Organization Quality of Life (WHOQOL)-BREF questionnaires. Mean, median, range, standard deviation, percentages, univariable, and multivariable logistic regression were analyzed with SPSS version 23.0 software (IBM Corp., Armonk, NY).ResultsThe mean age of the study patients was 53.6 years (SD 2.6) and they were mostly male (71.9%). Atherosclerotic peripheral vascular disease (PVD) was the most common indication (37.5%) of amputation, and below-the-knee amputation (46.88%) was the most commonly performed procedure. There was a significant increment in both PCS (p-value= 0.001), MCS scores (p-value=0.0001) of SF-12 and physical (p-value=0.0001) and psychological domains (p-value=0.001) of the WHOQOL-BREF questionnaire in the postoperative period. A total of 83.9% of patients have used prostheses, and 15.6% had mortality.ConclusionsMajor amputations can significantly affect the quality of life of patients, and all efforts should be made to avoid factors that adversely affect their quality of life.

The causes of holes and loss of physical integrity in long\u2010lasting insecticidal nets

BackgroundLong-lasting insecticidal nets (LLINs) are expected to last for at least 3 years, but whilst this may be achieved from an insecticidal perspective, physical protection is frequently compromised much earlier because of the rapid accumulation of holes during use. To understand why LLINs are so susceptible to loss of physical integrity, thousands of hole damage sites in LLINs retrieved from the field in Africa and Asia were forensically studied to identify the persistent underlying causes.MethodsA total of 525 LLINs consisting of six different brands from five different countries across Africa and Asia were collected from the field after 1 to 3 years in use. More than 42,000 individual sites of hole damage were analysed based on the morphology and size of each individual hole, aided by optical microscopy (OM) and scanning electron microscopy (SEM). The fracture morphology enabled positive identification of the underlying mechanisms of the damage.ResultsAcross all LLINs and geographical settings, mechanical damage is the primary cause of holes and loss of physical integrity in LLINs (63.14% by frequency and 81.52% by area). Snagging is the single most frequent mechanical damage mechanism, whilst the largest sized holes in LLINs result from seam failure and tearing. Abrasion and hole enlargement are also responsible for a progressive loss in the physical integrity of nets. Collectively, these five modes of mechanical damage can be expected to result from normal use of LLINs by households. Evidence of deliberate cutting, burn holes and rodent damage was observed to a lesser degree, which LLINs are not designed to withstand.ConclusionsLoss of physical integrity in LLINs is an inevitable consequence of using a vector control product that has an inherently low resistance to mechanical damage during normal use. To improve performance, new specifications based on laboratory textile testing is needed, to assess the resistance of LLIN products to the primary causes of mechanical damage when in use, which are snagging, tearing, abrasion and hole enlargement. Seam construction also needs to meet a revised minimum standard to reduce the risk of a rapid loss of physical integrity during use.

Invited Presentation: Li-Ion Battery Safety Considerations during Transportation, Storage, and Disposal

The energy of a Li-ion cell is in average about 3,250 kJ/kg. About ¼ of this energy is related to electrochemical energy (chemical energy convertible into electrical energy via normal use or short circuit) and ¾ to thermal energy (chemical energy convertible only in thermal energy released at suitable stimulation; e.g. short circuit). The main safety related events are overcharge, external heating, external and internal short circuits, and mechanical deformations of the cell/battery case. These unpredictable events may leads to a temperature increase and at T > 120 °C by internal chemical processes (SEI layer breakup, anode-electrolyte reaction) with gas development and internal pressure increase to cell container rupture at predetermined breaking points. Gas and electrolyte will escape through the rupture holes into the environment and, eventually, inflame by an external ignition source. A further temperature increase till about 200 °C triggers high rate chemical reactions (cathode decomposition with oxygen development, oxygen reaction with the electrolyte, electrolyte decomposition) leading to a very rapid temperature rise (thermal runaway) followed by flames caused by reaching the self-ignition temperature of the electrolyte (~ 450 °C) and possibly explosions. The specific occurrence of most of the above described safety related events, that may occur during the Li-ion battery life cycle phases of transportation, storage, and disposal, will be discussed in this presentation. During transportation and storage, external heating, external and internal short circuits, and mechanical deformations, are the events most likely to happen. Measures which can prevent them (e.g. reliable and low flammable packaging, thermal barriers) and transport related standards (e.g. UN 38.3) are described.The safety hazard in the disposal phase of the cell/battery are also associated with external heating, external and internal short circuits, and mechanical deformations. After collections it is to proof whether the battery is defective (not all functions properly) or damaged (loss of physical integrity). Defective batteries with capacity ≤ 80 % of the nominal value (end-of-life by definition) could be still used in lower demanding applications, e.g. stationary storage in PV houses. Damaged batteries and defective batteries with << 80 % capacity and other malfunctions have to be recycled. In order to reduce the safety risk before the recycling process (including transport), it is advisable to de-energize the battery by low current discharge and finally short it permanently.

Formulation and characterization of hydrochlorothiazide solid lipid microparticles based on lipid matrices of Irvingia fat.

Introduction:The purpose of this study was to improve the solubilization, bioavailability, and permeability of hydrochlorothiazide (HCTZ) by the formulation and characterization of HCTZ solid lipid microparticles (SLMs) based on fat derived from Irvingia gabonensis var. excelsa (Irvingia wombolu) and Phospholipon®90G (P90G).Materials and Methods:Irvingia fat was extracted from the nut of I. gabonensis var. excelsa using petroleum ether (40-60°C). HCTZ loaded SLM were formulated using hot homogenization method with 5% w/w Irvingia fat/P90G at each of 1:0, 9:1, 4:1, and 3:1 ratios, 1% w/w HCTZ, 1.5% w/w Labrasol® surfactant and distilled water. Subsequently, particle size analysis, pH, syringeability, drug encapsulation efficiency (EE%), yield, freeze-thaw cycle test, drug release, diffusion, and kinetics were evaluated.Results:The SLM dispersions showed a particle size range of 10.15 ± 2.36 to 13.50 ± 6.88 μm and pH of 5.6-6.4 while dispersions containing 3:1 Irvingia fat/P90G passed through most of the needles (18G, 21G, and 22G) after syringeability studies. A single freeze-thaw cycle caused loss of physical integrity. The EE% of the SLMs were ≥80%, with high yield. The highest drug release and diffusion was observed with SLMs prepared with 3:1 Irvingia fat-P90G mixture (HDP3) and Higuchi model best described the kinetics of the HCTZ release by Fickian diffusion.Conclusion:The release and permeability of HCTZ was improved by its incorporation into Irvingia fat and P90G (3:1) as SLMs.

Post-traumatic stress disorder: present and future.

Post-traumatic stress disorder (PTSD) and acute stress disorder (ASD) differ from almost every other psychiatric diagnosis in that they may only be diagnosed with reference to an aetiological event - an external traumatic stressor. ASD occurs immediately after the stressor and is comparatively short-lived, while PTSD is a prolonged abnormal response that may take months to develop. The types of stressor leading to ASD and PTSD are identical and were intended to be tightly defined, involving a perceived threat of death, serious injury or loss of physical integrity. It is useful initially to distinguish ASD and PTSD from adjustment disorders, which are also diagnosed only after an observable life event. An adjustment disorder may be thought of as a gradual and prolonged response to stressful changes in a person's life. The range of stressors precipitating an adjustment disorder is potentially much broader than that precipitating ASD or PTSD, as a threat of death or injury is not needed. Indeed, a 'threat' as such is not needed, as the event may be a loss. Events such as job loss or the breakup of a relationship may lead to an adjustment disorder, as well as threats such as accidents or assaults. The diagnostic criteria for adjustment disorder do not specify what the immediate response, if any, to the precipitating stressor must be.

Mitochondrial K+ transport and cardiac protection during ischemia/reperfusion

Mitochondrial ion transport, oxidative phosphorylation, redox balance, and physical integrity are key factors in tissue survival following potentially damaging conditions such as ischemia/reperfusion. Recent research has demonstrated that pharmacologically activated inner mitochondrial membrane ATP-sensitive K+ channels (mitoK(ATP)) are strongly cardioprotective under these conditions. Furthermore, mitoK(ATP) are physiologically activated during ischemic preconditioning, a procedure which protects against ischemic damage. In this review, we discuss mechanisms by which mitoK(ATP) may be activated during preconditioning and the mitochondrial and cellular consequences of this activation, focusing on end-effects which may promote ischemic protection. These effects include decreased loss of tissue ATP through reverse activity of ATP synthase due to increased mitochondrial matrix volumes and lower transport of adenine nucleotides into the matrix. MitoK(ATP) also decreases the release of mitochondrial reactive oxygen species by promoting mild uncoupling in concert with K+/H+ exchange. Finally, mitoK(ATP) activity may inhibit mitochondrial Ca2+ uptake during ischemia, which, together with decreased reactive oxygen release, can prevent mitochondrial permeability transition, loss of organelle function, and loss of physical integrity. We discuss how mitochondrial redox status, K+ transport, Ca2+ transport, and permeability transitions are interrelated during ischemia/reperfusion and are determinant factors regarding the extent of tissue damage.

Instantaneous, quantitative single-cell viability assessment by electrical evaluation of cell membrane integrity with microfabricated devices

Abstract Cell viability determination is an important process in life science. The loss of physical integrity in the plasma membrane is one of the major indications of cell death. Cell viability is thus usually determined through examination of membrane integrity with colorometric or fluorescent dyes. It occurred to us that when cell membrane loses the ability to exclude macromolecule dyes, its permeability to ions should also change, which could result in change in the electrical properties of the cell membrane. Therefore, evaluating the electrical properties of cell membrane should provide an indication on membrane integrity. We have designed and fabricated a chip to measure electrical currents that flow through single cells. For the purpose of detecting cell viability, the electrical measurements were correlated with conventional fluorescent dye assays that are typically used to distinguish between dead and live cells. Our experiments on human prostate carcinoma cells demonstrated that the electrical currents flow through live cells and membrane-impaired cells were substantially different. The dynamic processes of cell damage induced by various concentrations of Triton X100™, a cell lysing compound, have also been investigated. Our experimental results suggest that evaluation of cell membrane integrity by electrical measurements provides a simple, quantitative and instantaneous method for cell viability determination, which could be very useful in fundamental cell death study as well as cell-based biosensors for toxic-detection.

A multi‐technique study of the spontaneous oxidation of N‐hexane plasma polymers

AbstractLong‐term compositional changes were observed when n‐hexane plasma polymers were stored in air at ambient temperature. These post‐deposition changes were monitored over periods exceeding one year using XPS, grazing angle FTIR, and SEM. A rapid initial increase in the oxygen content was followed by a slower oxygen uptake, which continued for many months. In contrast to the reported autocatalytic acceleration of the oxidation of polyolefins, the rate of oxidation of n‐hexane plasma polymers was found to decrease continuously, and it did not proceed to the same extent toward higher oxidation states. The plasma polymer coatings did not show physical manifestations of oxidative degradation such as cracking, reduction in thickness, or loss of physical integrity. Comparison of the XPS and FTIR data suggested that the top few nanometers of the plasma polymer coatings oxidized at a faster rate than the “bulk.” The experimental data were interpreted using a model comprising reactions known from the oxidative degradation of polyolefins: carbon‐centered radicals, trapped in the course of the plasma deposition, combine with atmospheric oxygen to form metastable peroxy radicals and hydroperoxides, which decompose to generate a variety of stable product groups such as hydroxyl, carbonyl, and carboxylic groups. There was broad agreement between the XPS data and the time dependence of particular species in model calculations. © 1994 John Wiley &amp; Sons, Inc.

Effect of Li/MgO methane coupling catalyst on alonized steel reactors

Alonized 316 stainless steel reactors were used in life tests of a Li/MgO methane coupling catalyst. Severe corrosion of the portion of the reactor in contact with the catalyst bed was observed. Loss of physical integrity and chemical passivity resulted from layer formations of differing elemental compositions from the bulk metal. Chromium was leached from the stainless steel alloy and deposited on the catalyst. There were no adverse changes in those portions of the reactor not in direct contact with the catalyst. These results demonstrate that Alonized 316 stainless steel is unsuitable for use in methane coupling service with this lithium-containing catalyst.