Xe Affinities of Water-Soluble Cryptophanes and the Role of Confined Water

Given their relevance to drug design and chemical sensing, host–guest interactions are of broad interest in molecular science. Natural and synthetic host molecules provide vehicles for understanding selective molecular recognition in aqueous solution. Here, cryptophane–Xe host–guest systems are considered in aqueous media as a model molecular system that also has important applications. 129Xe–cryptophane systems can be used in the creation of biosensors and powerful contrast agents for magnetic resonance imaging applications. Detailed molecular information on the determinants of Xe affinity is difficult to obtain experimentally. Thus, molecular simulation and free energy perturbation methods were applied to estimate the affinities of Xe for six water-soluble cryptophanes. The calculated affinities correlated well with the previously measured experimental values. The simulations provided molecular insight on the differences in affinities and the roles of conformational fluctuations, solvent, and counter ions on Xe binding to these host molecules. Displacement of confined water from the host interior cavity is a key component of the binding equilibrium, and the average number of water molecules within the host cavity is correlated with the free energy of Xe binding to the different cryptophanes. The findings highlight roles for molecular simulation and design in modulating the relative strengths of host–guest and host–solvent interactions

Pulmonary tuberculosis in infants: radiographic and CT findings

OBJECTIVE: As complications of tuberculosis are frequent in infancy, correct diagnosis of tuberculosis in infants is important. The purposes of this study are to summarize radiographic and CT findings of pulmonary tuberculosis in infants and to determine the radiologic features frequently seen in infants with this disease. CONCLUSION: Frequent radiologic findings of pulmonary tuberculosis in infants are mediastinal or hilar lymphadenopathy with central necrosis and air-space consolidations, especially masslike consolidations with low-attenuation areas or cavities within the consolidation. Disseminated pulmonary nodules and airway complications are also frequently detected in this age group. CT is a useful diagnostic technique in infants with tuberculosis because it can show parenchymal lesions and tuberculous lymphadenopathy better than chest radiography. CT scans can also be helpful when chest radiographs are inconclusive or complications of tuberculosis are suspected

Power Doppler Imaging in Acute Renal Vein Occlusion and Recanalization: a Canine Model

OBJECTIVE: To evaluate the dynamic changes of the power Doppler (PD) in acute renal vein occlusion and recanalization in a canine model. MATERIALS AND METHODS: We performed a PD of the kidney during graded renal vein occlusion and recanalization induced by balloon inflation and deflation in nine dogs. The PD images were transferred to a personal computer, and the PD signals were quantified. RESULTS: We observed the temporal change of the PD signal during renal vein occlusion and recanalization, with a decrease in the PD signal during occlusion and an increase during recanalization. The mean PD signal decreased gradually as the renal vein was occluded, and conversely increased gradually with sequential relief of occlusion. The sequential change of the mean value of the PD signal was statistically significant. CONCLUSION: The PD can detect a change in renal blood flow during acute renal vein occlusion and recanalization in a canine model. The PD may be used as a helpful tool for the early detection of acute renal vein thrombosis and the monitoring of renal perfusion

Clinical Application of Liver MR Imaging in Wilson's Disease

Objective: To determine whether there is a correlation between liver MR findings and the clinical manifestations and severity of liver dysfunction in patients with Wilson`s disease. Materials and Methods: Two radiologists retrospectively evaluated MR images of the liver in 50 patients with Wilson`s disease. The Institutional Review Board approved this retrospective study and informed consent was waived. MR images were evaluated with a focus on hepatic contour abnormalities and the presence of intrahepatic nodules. By using Fisher`s exact test, MR findings were compared with clinical presentations (neurological and non-neurological) and hepatic dysfunction, which was categorized by the Child-Pugh classification system (A, B and C). Follow-up MR images were available for 17 patients. Results: Contour abnormalities of the liver and intrahepatic nodules were observed in 31 patients (62%) and 25 patients (50%), respectively. Each MR finding showed a statistically significant difference (p < 0.05) among the three groups of Child-Pugh classifications (A, n = 36; B, n = 5; C, n = 9), except for splenomegaly (p = 0.243). The mean age of the patients with positive MR findings was higher than that of patients with negative MR findings. For patients with Child-Pugh class A (n = 36) with neurological presentation, intrahepatic nodules, surface nodularity, and gallbladder fossa widening were more common. Intrahepatic nodules were improved (n = 8, 47%), stationary (n = 5, 29%), or aggravated (n = 4, 24%) on follow-up MR images. Conclusion: MR imaging demonstrates the contour abnormalities and parenchymal nodules of the liver in more than half of the patients with Wilson`s disease, which correlates with the severity of hepatic dysfunction and clinical manifestations.Cope-Yokoyama S, 2010, WORLD J GASTROENTERO, V16, P1487, DOI 10.3748/wjg.v16.i12.1487Akhan O, 2009, EUR J RADIOL, V69, P147, DOI 10.1016/j.ejrad.2007.09.029Taly AB, 2007, MEDICINE, V86, P112, DOI 10.1097/MD.0b013e318045a00eMerle U, 2007, GUT, V56, P115, DOI 10.1136/gut.2005.087262Akpinar E, 2007, EUR J RADIOL, V61, P25, DOI 10.1016/j.ejrad.2006.11.006Kozic D, 2006, ACTA RADIOL, V47, P624, DOI 10.1080/02841850600702176Kim TJ, 2006, AM J NEURORADIOL, V27, P1373SEO JK, 2006, KOREAN J HEPATOL, V12, P333Panagiotakaki E, 2004, AM J MED GENET A, V131A, P168, DOI 10.1002/ajmg.a.30345Chu WCW, 2004, AM J ROENTGENOL, V183, P1339ALA A, 2004, CLIN LIVER DIS, V8, P787Gitlin JD, 2003, GASTROENTEROLOGY, V125, P1868, DOI 10.1053/S0016-5085(03)01512-9Ferenci P, 2003, LIVER INT, V23, P139Akhan O, 2002, EUR RADIOL, V12, pS66, DOI 10.1007/s00330-002-1589-6Awaya H, 2002, RADIOLOGY, V224, P769, DOI 10.1148/radiol.2243011495Ito K, 1999, RADIOLOGY, V211, P723Ko SF, 1998, ABDOM IMAGING, V23, P56MERGO PJ, 1994, RADIOGRAPHICS, V14, P1291BULL PC, 1993, NAT GENET, V5, P327TANZI RE, 1993, NAT GENET, V5, P344DAVIES SE, 1989, HISTOPATHOLOGY, V15, P385CANCADO EL, 1987, ARQ NEURO-PSIQUIAT, V45, P131CHILD CG, 1964, LIVER PORTAL HYPERTE, P50

Measurement of the prompt J/psi and psi(2S) polarizations in pp collisions at sqrt(s) = 7 TeV

The polarizations of prompt J/psi and psi(2S) mesons are measured in proton-proton collisions at sqrt(s) = 7 TeV, using a dimuon data sample collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.9 inverse femtobarns. The prompt J/psi and psi(2S) polarization parameters lambda[theta], lambda[phi], and lambda[theta, phi], as well as the frame-invariant quantity lambda(tilde), are measured from the dimuon decay angular distributions in three different polarization frames. The J/psi results are obtained in the transverse momentum range 14 &lt; pt &lt; 70 GeV, in the rapidity intervals abs(y) &lt; 0.6 and 0.6 &lt; abs(y) &lt; 1.2. The corresponding psi(2S) results cover 14 &lt; pt &lt; 50 GeV and include a third rapidity bin, 1.2 &lt; abs(y) &lt; 1.5. No evidence of large transverse or longitudinal polarizations is seen in these kinematic regions, which extend much beyond those previously explored

Role of fruit juice in achieving the 5-a-day recommendation for fruit and vegetable intake

Although there is strong evidence that consumption of fruit and vegetables is associatedwith a reduced rate of all-cause mortality, only a minority of the population consumes5 servings a day, and campaigns to increase intake have had limited success.This review examines whether encouraging the consumption of fruit juice might offera step toward the 5-a-day target. Reasons given for not consuming whole fruit involvepracticalities, inconvenience, and the effort required. Psychologically, what isimportant is not only basic information about health, but how individuals interprettheir ability to implement that information. It has been argued that fruit juice avoidsthe problems that commonly prevent fruit consumption and thus provides a practicalmeans of increasing intake and benefitting health through an approach with whichthe population can readily engage. Those arguing against consuming fruit juice emphasizethat it is a source of sugar lacking fiber, yet juice provides nutrients such asvitamin C, carotenoids, and polyphenols that offer health-related benefits. Actively encouragingthe daily consumption of fruit juice in public health policy could help populationsachieve the 5-a-day recommendation for fruit and vegetable intake

Dynamic Properties of Water Confined in Graphene-Based Membrane: A Classical Molecular Dynamics Simulation Study

We performed molecular dynamics simulations of water molecules inside a hydrophobic membrane composed of stacked graphene sheets. By decreasing the density of water molecules inside the membrane, we observed that water molecules form a droplet through a hydrogen bond with each other in the hydrophobic environment that stacked graphene sheets create. We found that the water droplet translates as a whole body rather than a dissipate. The translational diffusion coefficient along the graphene surface increases as the number of water molecules in the droplet decreases, because the bigger water droplet has a stronger van der Waals interaction with the graphene surface that hampers the translational motion. We also observed a longer hydrogen bond lifetime as the density of water decreased, because the hydrophobic environment limits the libration motion of the water molecules. We also calculated the reorientational correlation time of the water molecules, and we found that the rotational motion of confined water inside the membrane is anisotropic and the reorientational correlation time of confined water is slower than that of bulk water. In addition, we employed steered molecular dynamics simulations for guiding the target molecule, and measured the free energy profile of water and ion penetration through the interstice between graphene sheets. The free energy profile of penetration revealed that the optimum interlayer distance for desalination is ~10 &Aring;, where the minimum distance for water penetration is 7 &Aring;. With a 7 &Aring; interlayer distance between the graphene sheets, water molecules are stabilized inside the interlayer space because of the van der Waals interaction with the graphene sheets where sodium and chloride ions suffer from a 3&ndash;8 kcal/mol energy barrier for penetration. We believe that our simulation results would be a significant contribution for designing a new graphene-based membrane for desalination

Using DNA to Link Gold Nanoparticles, Polymers and Molecules: a Theoretical Perspective

This Perspective describes theoretical studies aimed at understanding the structural and thermal properties of materials in which DNA is used to link gold nanoparticles, or polymers or organic molecules. Particularly in the case of gold nanoparticles, the materials derived from this structural motif have proven to be important for biological sensing and other applications, however additional applications may arise as a result of recent advances in the preparation of crystalline materials based on DNA-linked particles. From a theory perspective these are challenging materials to describe due to the large number of atoms, and the polyelectrolyte character of DNA, however there has been important progress recently using all-atom and coarse-grained molecular dynamics, and with analytical theory. Among topics that we discuss are the structure and density of DNA when attached to gold particles, and the size and melting properties of DNA-linked nanoparticles in different environments

Exfoliation of Electrolyte-Intercalated Graphene: Molecular Dynamics Simulation Study

Ethylene carbonate (EC) is one of the most common electrolyte for lithium ion batteries, but it has a narrow working temperature range. Despite the structural similarity, propylene carbonate (PC) has a wider working temperature range as an electrolyte, but it induces exfoliation of the graphite anode. To understand the different behavior of EC and PC electrolytes at the atomistic level, we performed molecular dynamics (MD) simulations of electrolyte intercalated graphene sheets. We observed no diffusion of electrolyte between graphene sheets when interlayer distance is less than 6 Å, but both of EC and PC form monolayer between graphene sheets with comparable density when interlayer distance is 7–8 Å. Because of the size difference, the intercalated PC molecules induce a longer separation distance between graphene sheets compared to that of EC. The longer separation with PC intercalant induces more frequent sliding-exfoliation movement. We found that the exfoliation diffusion coefficient of the graphene sheet with PC intercalant is ∼200 times larger than that with EC intercalant. One graphene diffuses and exfoliates from other graphene through sliding displacement rather than vertical separation because of steric interaction with electrolyte molecules in the bulk phase. For calculating the free energy changes of exfoliation, we constructed potential of means force using steered molecular dynamics simulations and found that the energy barrier of exfoliation of EC intercalated graphene sheets is ∼45 kcal/mol where it is ∼4 kcal/mol for PC intercalated graphene sheets. We also analyzed the static and dynamic properties of electrolyte confined between two graphene sheets. The self-diffusion coefficient of confined PC is larger than that of EC, but smaller in the bulk phase. We also found that the decaying of the dipole rotation autocorrelation of confined electrolyte is slower than that in the bulk phase. The dynamic properties of the graphene in two different electrolytes reported in this paper can be used for designing new anode materials with better performance

Use of Dexpanthenol for Atopic Dermatitis&mdash;Benefits and Recommendations Based on Current Evidence

Background: Atopic dermatitis (AD) is an inflammatory skin disease of multiple phenotypes and endotypes, and is highly prevalent in children. Many people of all ages, including active adolescents, pregnant women, and the elderly, suffer from AD, experiencing chronicity, flares, and unexpected relapse. Dexpanthenol has multiple pharmacological effects and has been employed to treat various skin disorders such as AD. We aimed to summarize the up-to-date evidence relating to dexpanthenol and to provide a consensus on how to use dexpanthenol effectively for the treatment of AD. Methods: The evidence to date on the application and efficacy of dexpanthenol in AD was reviewed. The literature search focused on dexpanthenol use and the improvement of skin barrier function, the prevention of acute flares, and its topical corticosteroid (TCS) sparing effects. Evidence and recommendations for special groups such as pregnant women, and the effects of dexpanthenol and emollient plus in maintenance therapy, were also summarized. Results: Dexpanthenol is effective and well-tolerated for the treatment of AD. Dexpanthenol improves skin barrier function, reduces acute and frequent flares, has a significant TCS sparing effect, and enhances wound healing for skin lesions. Conclusion: This review article provides helpful advice for clinicians and patients on the proper maintenance treatment of AD. Dexpanthenol, as an active ingredient in ointments or emollients, is suitable for the treatment and maintenance of AD. This paper will guide dermatologists and clinicians to consider dexpanthenol as a treatment option for mild to moderate AD