Partial Phi Research Articles

Is there still protected health information in openly available PowerPoint files?

IntroductionPowerPoint presentations containing radiographic images continue to be an important educational tool for healthcare professionals. When properly deidentified, these radiographic imaging files are valuable and do not pose any privacy concerns for patients. However, when these images are not properly managed, patient information can be uncovered; raising concerns about patient privacy and potential legal consequences for healthcare systems and academic institutions. This study revisited and expanded upon previous work published by Weadock et. al in an attempt to see how this issue has changed in the last 15 years. MethodsThis study consisted of 8 separate Google Web searches related to a medical imaging modality. Each PowerPoint file was manually inspected for imaging files including x rays, CT scans, MRI's, PET scans, CT and MR angiography and ultrasounds. If a PowerPoint contained an image file, it was then inspected for PHI. Full PHI included all of the following: patient's full name, medical registration number (MRN), date and a geographic indicator smaller than a state. ResultsThe first two Google searches “Magnetic Resonance Imaging filetype:ppt” and “Cardiac CT CAT Scan filetype:ppt” returned 146 search results with 7.6 % containing full PHI. “Radiology Chest X-ray filetype:ppt” resulted in accessible PHI in 40 % of the presentations with images and “Post-Operative CT Scan filetype:ppt” resulted in accessible PHI in 29 %. Magnetic Resonance Imaging filetype:pptx” returned 0 results with PHI. “Cardiac CT CAT scan filetype:pptx” returned 1 result with partial PHI.“Radiology Chest X-ray filetype:pptx” contained 4 results with partial PHI and 1 result with full PHI. “Post-Operative CT scan filetype:pptx” contained 2 presentations with partial PHI. DiscussionWhile a declining percentage of PowerPoint files containing PHI is reassuring, this follow up study demonstrated that PHI can still be easily accessed openly on the internet by anyone who has basic familiarity with Microsoft PowerPoint. Work remains to continue to educate users on how to properly protect patient information in PowerPoint files. Appropriately protecting private healthcare information is essential for patient safety and can prevent unintentional HIPAA violations. Radiologists are uniquely positioned to educate other healthcare providers on how to properly remove PHI from radiologic imaging files.

Leukemic cells resist lysosomal inhibition through the mitochondria-dependent reduction of intracellular pH and oxidants.

Acidic lysosomes are indispensable for cancer development and linked to chemotherapy resistance. Chloroquine (CQ) and functional analogues have been considered as a potential solution to overcome the cancer progression and chemoresistance by inhibiting the lysosome-mediated autophagy and multidrug exocytosis. However, their anti-cancer efficacy in most clinical trials demonstrated modest improvement. In this study, we investigated the detailed mechanisms underlying the acquired resistance of K562 leukemic cells to CQ treatment. In response to 5-80μM CQ, the lumen pH of endosomal-lysosomal system immediately increased and gradually reached dynamic equilibrium within 24h. Leukemic cells produced more acidic organelles to tolerate 5-10μM CQ. CQ (20-80μM) concentration-dependently triggered cytosolic pH (pHi) rise, G0/G1 arrest, mitochondrial depolarization/fragmentation, and necrotic/apoptotic cell death. Oxidant induction by CQ was responsible for the mitochondria-dependent cytotoxicity and partial pHi elevation. Cells that survived the CQ cytotoxicity were accompanied with increased mitochondria. Under the 80μM CQ challenge, co-treatment with the inhibitor of F0 part of mitochondrial H+-ATP synthase, oligomycin (40nM), prevented the elevation of oxidants as well as pHi, and attenuated stresses on mitochondria, cell survival, and cell proliferation. Besides, oligomycin-treated cells obviously displayed the lysosomal peripheralization and plasma membrane blebbing, suggesting that these cells were in process of lysosomal exocytosis and microvesicle release. Enhanced motion of these secretory processes allowed the cells to exclude CQ and repair necrotic injury. Together, the oxidant production and the proton dynamic interconnection among lysosomes, mitochondria, and cytosol are crucial for leukemic susceptibility to lysosomotropic chemotherapeutics.

Volumetric Investigations on Molecular Interactions of Glycine/l-alanine in Aqueous Citric Acid Solutions at Different Temperatures

Apparent molar volumes (phi_{V}) of glycine/l-alanine in water and in aqueous citric acid (CA) solutions of varying concentrations, i.e. (0.05, 0.10, 0.20, 0.30, 0.40 and 0.50) mol·kg−1 were determined from density measurements at temperatures T = (288.15, 298.15, 308.15, 310.15 and 318.15) K and at atmospheric pressure. Limiting partial molar volumes (phi_V^{text{o}}) and their corresponding partial molar volumes of transfer (Delta_{text{tr}} phi_{V} ) have been calculated from the phi_{V} data. The negative Delta_{text{tr}} phi_{V} values obtained for glycine/l-alanine from water to aqueous CA solutions indicate the dominance of hydrophilic–hydrophobic/hydrophobic–hydrophilic and hydrophobic–hydrophobic interactions over ion/hydrophilic–dipolar interactions. Further, pair and triplet interaction coefficients, i.e.(V_{text{AB}} );{text{and}}; (V_{text{ABB}} ) along with hydration number (n_{text{H}} ) have also been calculated. The effect of temperature on the volumetric properties of glycine/l-alanine in water and in aqueous CA solutions has been determined from the limiting partial molar expansibilities (partial phi_{V}^{text{o}} /partial T)_{p} and their second-order derivative (partial^{2} phi_{V}^{text{o}} /partial T^{2} )_{{P}}. The apparent specific volumes (nu_{phi} ) for glycine and l-alanine tend to approach sweet taste behavior both in the presence of water and in aqueous CA solutions. The nu_{phi} values for glycine/l-alanine increase with increase in concentration of CA at all temperatures studied. This reveals that CA helps in enhancing the sweet taste behavior of glycine/l-alanine which also supports the dominance of hydrophobic–hydrophobic interactions.

Duality between k-essence and Rastall gravity

The k-essence theory with a power-law function of (partial phi )^2 and Rastall’s non-conservative theory of gravity with a scalar field are shown to have the same solutions for the metric under the assumption that both the metric and the scalar fields depend on a single coordinate. This equivalence (called k–R duality) holds for static configurations with various symmetries (spherical, plane, cylindrical, etc.) and all homogeneous cosmologies. In the presence of matter, Rastall’s theory requires additional assumptions on how the stress-energy tensor non-conservation is distributed between different contributions. Two versions of such non-conservation are considered in the case of isotropic spatially flat cosmological models with a perfect fluid: one (R1) in which there is no coupling between the scalar field and the fluid, and another (R2) in which the fluid separately obeys the usual conservation law. In version R1 it is shown that k–R duality holds not only for the cosmological models themselves but also for their adiabatic perturbations. In version R2, among other results, a particular model is singled out that reproduces the same cosmological expansion history as the standard Lambda CDM model but predicts different behaviors of small fluctuations in the k-essence and Rastall frameworks.

Concentration Dependence of the Flory χ Parameter within Two-State Models

The Flory chi parameter is typically assumed to depend only on the temperature, T. Experimental results often require the replacement of this chi(T) by chieff, that depends also on the monomer volume fraction, phi, chieff(phi,T). Such chieff(phi,T) can arise from two state-models, proposed for polyetheleneoxide (PEO) and other neutral water-soluble polymers. The predicted phi dependence of chibar=chieff-(1-phi)\partial \chieff/\partial phi, obtainable from colligative properties, differs qualitatively between the various models: (i) The model of Karlstrom (J. Phys. Chem. 1985, 89, 4962) yields \partial chibar/\partial phi > 0 while the model of Matsuyama and Tanaka (Phys. Rev. Lett. 1990, 65, 341) and of Bekiranov et al (Phys. Rev. E 1997, 55, 577) allows for \partial chibar/\partial phi <0 (ii) chibar(phi) as calculated from the Karlstrom model, utilizing the parameters used to fit the phase diagram of PEO, agrees semiquantitatively with the experimental values. On the other hand, chibar(phi) similarly calculated from the model of Bekiranov et al. differs qualitatively from the measured results. Altogether, chibar(phi) provides useful measure for the performance of a model.

PH regulation in single CA1 neurons acutely isolated from the hippocampi of immature and mature rats.

1. We used the pH-sensitive fluorescent dye 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF) to study the regulation of intracellular pH (pHi) in single pyramidal neurons freshly isolated from the hippocampal CA1 region of immature (2- to 10-day-old) and more mature (21- to 30-day-old) rats. 2. Whether isolated from immature or mature rats, neurons had a broad range of initial pHi values (6.3-7.7) when the cells were examined in solutions buffered with Hepes and no CO2/HCO3-. The initial pHi distribution for neurons isolated from immature rats was best fitted with a Gaussian distribution with a mean of 6.95. In contrast, the initial pHi distribution for neurons isolated from mature rats was best fitted with the sum of two Gaussian distributions with means of 6.68 and 7.32. 3. When neurons with a relatively low initial pHi in Hepes-buffered solutions were acid loaded, pHi recovered very slowly. Neurons with a relatively high initial pHi recovered rapidly. The rate constant for the exponential pHi recovery increased with initial pHi. All pHi recoveries required Na+. 4. Both for neurons with a relatively high (> or = 7.05) and a relatively low (< 7.05) initial pHi, net acid extrusion rates (Jtotal = dpHi/dt x buffering power) decreased linearly with increasing pHi. Compared with the line for neurons with a relatively low initial pHi, that for neurons with a relatively high pHi had a significantly greater slope and was alkaline shifted by 0.6-0.7 pH units. 5. Removing external Na+ in the absence of CO2/HCO3- caused pHi to decrease by approximately 0.3 in neurons with a relatively low initial pHi, and by approximately 0.5 in neurons with a relatively high initial pHi. This initial acidification was followed by a slower, partial pHi recovery in approximately 32% of neurons with a relatively low initial pHi, but only approximately 14% of neurons with a relatively high pHi. 6. When exposed to CO2/HCO3-, all neurons initially acidified. Neurons with a relatively low initial pHi recovered to a pHi approximately 0.2 pH units greater than the initial value. Among neurons with higher initial pHi values, some did not recover at all, whereas others recovered to a value similar to or above the initial pHi. On average, the final CO2/HCO3- pHi for neurons with a relatively high initial pHi was similar to the pHi in Hepes buffer. Neurons with a relatively high pHi in Hepes buffer continued to be more alkaline (by approximately 0.2 pH units) in CO2/HCO3-. 7. When neurons with a relatively high initial pHi in Hepes (> or = 7.25) were exposed to CO2/HCO3- and then acid loaded, Jtotal values were more than twice the highest values observed in neurons with lower initial pHi values. Neurons with a moderate initial pHi in Hepes (7.05-7.24) had Jtotal values, at comparable pHi values, that were approximately 2-fold greater than for neurons with a relatively low initial pHi (< 7.05). 8. Thus, freshly isolated CA1 neurons of both mature and immature rats have a wide range of acid-base properties. Those with higher initial pHi values in a Hepes buffer tend to have greater Jtotal values in both Hepes and CO2/HCO3-, and tend to have higher steady-state pHi values in CO2/HCO3-.

Video microscopy of intracellular pH in primary cultures of rabbit proximal and early distal tubules

The purpose of this study was to investigate intracytoplasmic pH (pHi) regulation in primary cultures of proximal (PCT) and distal bright (DCTb) convoluted tubules. PCT and DCTb segments were microdissected from rabbit kidney cortex and cultured in a hormonally defined medium. The cultured epithelia were grown on semi-transparent permeable supports. The pHi was determined by video microscopy and digital image processing using 2,7-biscarboxyethyl-5(6)-carboxyfluorescein (BCECF) and measuring the ratio of BCECF fluorescence excited by two successive wavelengths (490 nm and 450 nm). Resting pHi values, determined in bicarbonate-free medium (extracellular pH: 7.40), were 7.25 +/- 0.02 (n = 23) and 7.17 +/- 0.04 (n = 30) for cultured PCT and DCTb respectively. After the acid-loading procedure, cultured proximal cells recovered their pHi by means of the classic Na+/H+ antiporter, sensitive to amiloride and located in the apical membrane only. In cultured DCTb part of the pHi recovery was mediated by a Na+/H+ exchange present in the basolateral side. Moreover, at physiological initial pHi values, chloride removal from the apical solution caused the pHi to increase in the presence of bicarbonate. In acidified cultured DCTb cells, a partial pHi recovery was induced in sodium-free media by 15 mM HCO(-3) in the presence of an outward chloride gradient. This pHi change was completely abolished by 4,4'-diisothiocyanostilbene 2,2'-disulfonic acid (1 mM). These data suggest that DCTb cells possess in apical anion/base exchanger that resembles the Na(+)-independent Cl-/HCO(-3) exchanger.