Strong enhancement of cage effects in water photolysis caused by interatomic Coulombic decay.

The impact of the solvent on the photodissociation of embedded molecules has been intensively investigated in the last decades. Collisions of photofragments with the solvating atoms or molecules can change their kinetic energy distribution or even lead to the de-excitation of the dissociating molecule to a bound electronic state quenching the dissociation. In this article we show that this cage effect is strongly enhanced if interatomic Coulombic decay (ICD) of the excited state becomes allowed. Ab initio calculations in H2O-Cl(-) cluster show that the ultra-fast dissociation of water in the à excited state is strongly quenched by ICD. We found that this very efficient quenching is due to two factors. First, the lifetimes of the à state due to ICD are short ranging between 6 and 30 fs. Second, nuclear dynamics is dominated by the chattering motion of the H atom between O and Cl(-) allowing ICD to act for longer times. We hope that this work will be an important first step in clarifying the impact of ICD on photodissociation of embedded molecules.

Rovibrational spectroscopy using a kinetic energy operator in Eckart frame and the multi-configuration time-dependent Hartree (MCTDH) approach.

For computational rovibrational spectroscopy the choice of the frame is critical for an approximate separation of overall rotation from internal motions. To minimize the coupling between internal coordinates and rotation, Eckart proposed a condition ["Some studies concerning rotating axes and polyatomic molecules," Phys. Rev. 47, 552-558 (1935)] and a frame that fulfills this condition is hence called an Eckart frame. A method is developed to introduce in a systematic way the Eckart frame for the expression of the kinetic energy operator (KEO) in the polyspherical approach. The computed energy levels of a water molecule are compared with those obtained using a KEO in the standard definition of the Body-fixed frame of the polyspherical approach. The KEO in the Eckart frame leads to a faster convergence especially for large J states and vibrationally excited states. To provide an example with more degrees of freedom, rotational states of the vibrational ground state of the trans nitrous acid (HONO) are also investigated.

Numeric kinetic energy operators for molecules in polyspherical coordinates.

Generalized curvilinear coordinates, as, e.g., polyspherical coordinates, are in general better adapted to the resolution of the nuclear Schrödinger equation than rectilinear ones like the normal mode coordinates. However, analytical expressions of the kinetic energy operators (KEOs) for molecular systems in polyspherical coordinates may be prohibitively complicated for large systems. In this paper we propose a method to generate a KEO numerically and bring it to a form practicable for dynamical calculations. To examine the new method we calculated vibrational spectra and eigenenergies for nitrous acid (HONO) and compare it with results obtained with an exact analytical KEO derived previously [F. Richter, P. Rosmus, F. Gatti, and H.-D. Meyer, J. Chem. Phys. 120, 6072 (2004)]. In a second example we calculated π → π* photoabsorption spectrum and eigenenergies of ethene (C(2)H(4)) and compared it with previous work [M. R. Brill, F. Gatti, D. Lauvergnat, and H.-D. Meyer, Chem. Phys. 338, 186 (2007)]. In this ethene study the dimensionality was reduced from 12 to 6 by freezing six internal coordinates. Results for both molecules show that the proposed method for obtaining an approximate KEO is reliable for dynamical calculations. The error in eigenenergies was found to be below 1 cm(-1) for most states calculated.

In vivo effects of allogeneic mesenchymal stem cells in a rat model of acute ischemic kidney injury.

OBJECTIVES: Renal ischemia-reperfusion injury (IRI) as a severe condition of acute kidney injury (AKI) is the most common clinical problem with high mortality rates of 35-60% deaths in hospital. Mesenchymal stem cells (MSC) due to unique regenerative characteristics are ideal candidates for the treatment of the ischemic injuries. This work is focused on the administration of MSC to IRI-induced AKI Wistar rats and evaluating their significance in AKI treatment. MATERIAL AND METHODS: Animals underwent surgical procedure and AKI was induced by 40 min bilateral renal pedicle clamping. Immediately after reperfusion, 2×106 rat bone marrow derived MSCs were injected via intra-parenchymal or intra-aortic route. RESULTS: Animals subjected to AKI after days 1 and 3 showed significant increase in the serum creatinine and blood urea nitrogen (BUN) concentration along with a declined glomerular filtration rate (GFR) when compared with non-ischemic animals. On the other hand, treated animals showed a significant enhanced regeneration as compared to ischemic animals in both administration route groups. CONCLUSION: According to the results concluded from the renoprotective effects of MSC in IRI/AKI, MSCs could be considered as promising therapeutic approach for AKI in clinical applications.

Different methods to determine the encapsulation efficiency of protein in PLGA nanoparticles.

BACKGROUND: Effective encapsulation of drugs into the delivery systems could increase the efficiency of nanoparticles in prevention and treatment of diseases. OBJECTIVE: The purpose of this study was to compare the different methods for determination of encapsulation efficiency of a model protein in the PLGA nanoparticles. METHODS: The various direct methods include dichloromethane, acetonitrile, modified acetonitrile and NaOH based extraction and radioactive methods were used to directly calculate the encapsulation efficiency of the loaded protein in the PLGA nanoparticles. Furthermore, indirect methods include BCA, Fluorescent and radioactive methods were compared. RESULTS: The encapsulation efficiencies determined by indirect methods include dichloromethane, acetonitrile, modified acetonitrile, NaOH based extraction and radioactive methods were 12.62% ± 1.97, 17.43% ± 2.51, 64.69% ± 4.31, 86.36% ± 2.25 and 90.15% ± 1.78, respectively. Moreover, the encapsulation efficiencies determined by indirect methods include BCA, fluorescent and radioactive methods were 81.46% ± 1.92, 88.23% ± 1.15 and 89.6% ± 1.9, respectively. CONCLUSIONS: Among the results obtained by indirect methods, radioactive and fluorescent methods showed more reliable. Moreover, NaOH and radioactive methods were the most reliable methods among the direct methods.

Full-dimensional MCTDH/MGPF study of the ground and lowest lying vibrational states of the bihydroxide H3O2(-) complex.

In this study, we present a full-dimensional (9D) quantum dynamical analysis of the lowest vibrational eigenstates of H3O2(-). We have made use of the Multiconfiguration Time-Dependent Hartree method in conjunction with both an analytical and a numerical representation of the Kinetic Energy Operator and the newly developed Multigrid POTFIT [D. Peláez, H.-D. Meyer, J. Chem. Phys. 138 (2013) 014108], an algorithm which performs the transformation of a high-dimensional (up to ~12D) Potential Energy tensor into product form. Many sets of top-down Multigrid POTFIT expansions, differing in the system coordinate definition (valence and Jacobi), as well as in the number of terms in the expansion, have been analyzed. Relaxations for the computation of the ground states energies have been carried out on these potentials, obtaining an excellent overall agreement with accurate previous Diffusion Monte Carlo (DMC) calculations, irrespective of the coordinate choice. The 24 lowest excited vibrational states of H3O2(-) have been computed by Block Relaxation and assigned for the first time. This has been carried out in two different pictures, namely: a 7D reduced dimensional one, in which the OH distances have been frozen at the Potential Energy Surface minimum, and a 9D full-dimensional one. The agreement between both descriptions is remarkable. The following fundamental modes have been characterized: OH torsion, OO stretching, OH wagging, OH rocking, and the elusive bridging H stretching. In particular, we provide a very accurate description of the latter in perfect agreement with experiment.

Diagnostic value of 99mTc-bombesin scintigraphy for differentiation of malignant from benign breast lesions.

OBJECTIVE: In this study, we evaluated the diagnostic accuracy of (99m)Tc-bombesin scintigraphy for differentiation of benign from malignant palpable breast lesions. (99m)Tc-Bombesin is a tracer with high affinity for gastrin-releasing peptide receptor, which is overexpressed on a variety of human tumors including breast carcinoma. MATERIALS AND METHODS: We examined 33 consecutive women who were referred to our center with suspicious palpable breast lesions but had no definitive diagnosis in other imaging procedures. A volume of 370-444 MBq of (99m)Tc-bombesin was injected and dynamic 1-min images were taken for 20 min immediately after injection in anterior view. Thereafter, two static images in anterior and prone-lateral views were taken for 5 min. Finally, single-photon emission computed tomography images were taken for each patient. Definitive diagnosis was based on biopsy and histopathological evaluation. RESULTS: The scan findings were positive in 19 patients and negative in 11 on visual assessment of the planar and single-photon emission computed tomography images. Pathologic examination confirmed breast carcinoma in 12 patients with positive scans and benign pathology for 18 patients. The overall sensitivity, specificity, negative and positive predictive values, and accuracy of this radiotracer for diagnosis of breast cancer were 100, 66.1, 100, 63, and 76%, respectively. Semiquantitative analysis improved the specificity of the visual assessment from 66 to 84%. CONCLUSION: Our study showed that (99m)Tc-bombesin scintigraphy has a high sensitivity and negative predictive value for detecting malignant breast lesions, but the specificity and positive predictive value of this radiotracer for differentiation of malignant breast abnormalities from benign ones are relatively low.

Radioimmunotherapy of MCF7 breast cancer cell line with 131I-PR81 monoclonal antibody against MUC1: comparison of direct and indirect radioiodination methods.

PR81 is a monoclonal antibody that binds with high affinity to MUC1, which is over expressed on breast and other tumors. The objective of this study was to compare the two labeling methods (direct and indirect radioiodination) for application of this antibody against MUC1 as a radioimmunotherapeutical agent.Monoclonal antibody (PR81) against the tandem repeat of the core protein (MUC1) was prepared, characterized, purified, and labeled with 131I using the direct (chloramin-T) and indirect (Fmoc-D-Tyr (tBu)-D-Tyr (tBu)-D-Lys (Boc)-OH (YYK) attached to N-hydroxysuccinimide as a linker between PR81 and 131I) methods. The immunoreactivity of 131I-PR81 and 131I-TP-PR81 complexes with MUC1 (the native protein), BSA-P20 (a 20 amino acid corresponding the tandem repeat of MUC1) and MCF7 cell line were performed by RIA. In vitro stability of 131I-PR81 and 131I-YYK-peptide-PR81 complexes in human serum was determined by thin layer chromatography (TLC). Cell toxicity and in vitro internalization studies were performed with the MCF7 cell line, and the tissue biodistribution of the 131I-PR81 and 131I- YYK-peptide -PR81 complexes was evaluated in normal BALB/c mice at 4, 24 and 48 hrs. The labeling efficiency was determined by measuring the percentage recovery of radioactivity in the final product relative to the initial activity in the shipment vial, was found to be 59.9% +/- 7.9% for direct and 50% +/- 3.2% for indirect methods. 131I-PR81 and 131I- YYK- peptide -PR81 complexes showed high immunoreactivity towards MUC1 protein, BSA-P20 and MCF7 cell line. In vitro stability of the labeled products in human serum which was measured by thin layer chromatography (TLC) was found to be more than 50% over 24 hr for 131I-PR81 and 70% for 131I- YYK-peptide -PR81 complexes. Cell toxicity and in vitro internalization studies showed that the 131I-PR81 and 131I- YYK-peptide -PR81 complexes inhibited 80% growth of the MCF7 cultured cell lines in vitro in a high concentration and up to 40% of the 131I-PR81 and 60% of the 131I- YYK-peptide -PR81 complexes internalized after 24 h. Biodistribution studies were performed in normal BALB/c mice at 4, 24 and 48 hrs post-injection. Thyroid and stomach levels from PR81 labeled with 131I- YYK-peptide were two- to three- fold less than those with directly labeled 131I-PR81, suggesting low recognition of its D-iodotyrosine residue by endogenous deiodinase. These results show that the indirect labeling was better than the indirect labeling and 131I- YYK-peptide -PR81 may be considered as a promising candidate for therapy of breast cancer.