Synthesis of Selenium Derivatives using Organic Selenocyanates as Masked Selenols: Chemical Reduction with Rongalite as a Simpler Tool to give Nucleophilic Selenides.

The chemical reduction within a family of organic selenocyanates, as masked selenols, using reducing agents, such as Rongalite, sodium dithionite, and sodium thiosulfate is investigated. Using Rongalite, the corresponding diselenides were obtained quantitatively and selectively in very good to excellent yields (51-100 %) starting from alkyl, aryl, and benzyl selenocyanates. The scope of the reaction is unaffected by the electronic nature of the substituents.

Older adults in psychedelic-assisted therapy trials: A systematic review.

Background: Growing clinical interest in psychedelic-assisted therapies has led to a second wave of research involving psilocybin, lysergic acid diethylamide (LSD), 3,4-methylenedioxymethamphetamine (MDMA) and other substances. Data suggests that these compounds have the potential to treat mental health conditions that are especially prevalent in older adults such as depression, anxiety, existential distress, and posttraumatic stress disorder.

Aims: The goal of this study was to quantify the prevalence of older adults enrolled in psychedelic clinical trials and explore safety data in this population.

A Dual Fluorescence-Spin Label Probe for Visualization and Quantification of Target Molecules in Tissue by Multiplexed FLIM-EPR Spectroscopy.

Simultaneous visualization and concentration quantification of molecules in biological tissue is an important though challenging goal. The advantages of fluorescence lifetime imaging microscopy (FLIM) for visualization, and electron paramagnetic resonance (EPR) spectroscopy for quantification are complementary. Their combination in a multiplexed approach promises a successful but ambitious strategy because of spin label-mediated fluorescence quenching.

Synthesis, Self-Assembly, and Biological Activities of Pyrimidine-Based Cationic Amphiphiles.

Pyrimidine-based cationic amphiphiles (PCAms), i.e., di-trifluoroacetic acid salts of 1-[1'-(1″,3″-diglycinatoxy-propane-2″-yl)-1',2',3'-triazole-4'-yl]methyl-3-alkylpyrimidines have been synthesized utilizing naturally occurring biocompatible precursors, like glycerol, glycine, and uracil/ thymine in good yields.

Riboflavin as Photoredox Catalyst in the Cyclization of Thiobenzanilides: Synthesis of 2-Substituted Benzothiazoles.

Benzothiazoles are synthesized from thiobenzanilides using riboflavin as a photosensitizer and potassium peroxydisulfate as a sacrificial oxidizing agent under visible light irradiation. The methodology accepts a broad range of functional groups and affords the 2-substituted benzothiazoles by transition-metal-free organic photoredox catalysis under very mild conditions.

Combined Experimental and Theoretical Studies on the Radical Nucleophile Addition Reaction for Sulfide- and Selenide-Centered Anions.

The reactivity of sulfur- and selenium-centered nucleophiles toward 1-naphthyl radicals was studied in dimethylsulfoxide. The photostimulated reaction of sulfide anions, SC(NH)CH (1), SC(NH)NH (2), and SC(NH)CH (3), renders, after the addition of MeI, methyl 1-naphthylsulfide as a main product together with bis(1-naphthyl) sulfide and naphthalene under irradiation. Concordantly, the reaction of selenide anions, SeC(NH)CH (4), SeC(NH)NH (5), and SeCN (6), produces methyl 1-naphthyl selenide, bis(1-naphthyl) selenide, and naphthalene in the presence of potassium tert-butoxide anion (entrainment conditions).

Photoinduced One-Electron Oxidation of Aromatic Selenides: Effect of the Structure on the Reversible Dimerization Reaction.

The photochemical one-electron oxidation of alkyl aryl selenides was studied by means of laser flash photolysis (355 nm). Quenching of the sensitizers in their excited state leads to selenide radical cation in the presence of selenium derivatives. The π-type dimer of methyl phenyl selenide radical cation was detected at 630 nm at expenses of the monomeric radical cation (530 nm).

Nanoparticle-cored dendrimers: functional hybrid nanocomposites as a new platform for drug delivery systems.

Nanoparticle-cored dendrimers (NCDs) are now offering themselves as versatile carriers because of their colloidal stability, tunable membrane properties and ability to encapsulate or integrate a broad range of drugs and molecules. This kind of hybrid nanocomposite aims to combine the advantages of stimuli-responsive dendritic coatings, in order to regulate the drug release behaviour under different conditions and improve the biocompatibility and in vivo half-time circulation of the inorganic nanoparticles. Size, surface chemistry and shape are key nanocarrier properties to evaluate.

Stereoselective one-pot synthesis of β-alkylsulfide enol esters. Base-triggered rearrangement under mild conditions.

A stereoselective one-pot procedure was developed to prepare S-substituted (Z)-enol esters through a base-triggered rearrangement. This transition metal-free multicomponent approach can be performed under an air atmosphere at room temperature, tolerates a wide set of chemical functionalities and generally affords high isolated yields. The (Z)-selectivity arises from the [1,4]-S- to O-acyl migration.

Sensing chiral drugs by using CdSe/ZnS nanoparticles capped with N-acetyl-L-cysteine methyl ester.

Chiral quantum dots (QDs), differing in their core or shell size and, consequently, in their optical properties, were synthesized by the treatment of commercially available amine-capped quantum dots with methyl ester N-acetyl-L-cysteine (CysP). Interestingly, their colloidal methanol solutions remain stable for several months. Their NMR and IR spectra were in accordance with CysP binding to the QD surface through two anchoring groups; its thiolate (strongly bound) and the carbonyl group of its ester (weaker bound) group, whereas their circular dichroism (CD) spectra showed a new broad redshifted band, suggesting that the attachment to the QD surface modified the conformational equilibrium towards conformer(s) with optical activity in this region.

MIRD pamphlet No. 20: the effect of model assumptions on kidney dosimetry and response--implications for radionuclide therapy.

Unlabelled: Renal toxicity associated with small-molecule radionuclide therapy has been shown to be dose-limiting for many clinical studies. Strategies for maximizing dose to the target tissues while sparing normal critical organs based on absorbed dose and biologic response parameters are commonly used in external-beam therapy. However, radiopharmaceuticals passing though the kidneys result in a differential dose rate to suborgan elements, presenting a significant challenge in assessing an accurate dose-response relationship that is predictive of toxicity in future patients.

Trilogy image-guided stereotactic radiosurgery.

Full integration of advanced imaging, noninvasive immobilization, positioning, and motion-management methods into radiosurgery have resulted in fundamental changes in therapeutic strategies and approaches that are leading us to the treatment room of the future. With the introduction of image-guided radiosurgery (IGRS) systems, such as Trilogy, physicians have for the first time a practical means of routinely identifying and treating very small lesions throughout the body. Using new imaging processes such as positron emission tomography/computed tomography (PET/CT) scans, clinics may be able to detect these lesions and then eradicate them with image-guided stereotactic radiosurgery treatments.

Dynamic targeting image-guided radiotherapy.

Volumetric imaging and planning for 3-dimensional (3D) conformal radiotherapy and intensity-modulated radiotherapy (IMRT) have highlighted the need to the oncology community to better understand the geometric uncertainties inherent in the radiotherapy delivery process, including setup error (interfraction) as well as organ motion during treatment (intrafraction). This has ushered in the development of emerging technologies and clinical processes, collectively referred to as image-guided radiotherapy (IGRT). The goal of IGRT is to provide the tools needed to manage both inter- and intrafraction motion to improve the accuracy of treatment delivery.

Ultrasonographic guidance for spinal extracranial radiosurgery: technique and application for metastatic spinal lesions.

Object: The relatively stationary anatomy of the intracranial compartment has allowed the development of stereotactic radiosurgery as an effective treatment option for many intracranial lesions. Difficulty in accurately tracking extracranial targets has limited its development in the treatment of these lesions. The ability to track extracranial structures in real time with ultrasound images allows a system to upgrade and interface pretreatment volumetric images for extracranial applications.

Bone marrow dosimetry using blood-based models for radiolabeled antibody therapy: a multiinstitutional comparison.

Unlabelled: Standardization of marrow dosimetry is of considerable importance when estimating dose-response for a multicentered clinical trial involving radionuclide therapy. However, it is only within the past five years that the intercomparison of marrow dosimetry results among separate clinical trials that use the same agent has become scientifically feasible. In this work, we have analyzed reported marrow dosimetry results from radioimmunotherapy trials and recalculated marrow absorbed doses at a central facility using a standard blood model with patient-specific source data.

Compact sources as the origin of the soft gamma-ray emission of the Milky Way.

The Milky Way is known to be an abundant source of gamma-ray photons, now determined to be mainly diffuse in nature and resulting from interstellar processes. In the soft gamma-ray domain, point sources are expected to dominate, but the lack of sensitive high-resolution observations did not allow for a clear estimate of the contribution from such sources. Even the best imaging experiment revealed only a few point sources, accounting for about 50% of the total Galactic flux.

A simple and reliable index for scoring rival stereotactic radiosurgery plans.

Purpose: A simple and robust index for ranking rival stereotactic radiosurgery plans is presented.

Methods: The radiosurgery plan score index, CGI (Conformity/Gradient Index), is an average of a conformity score and a gradient score. Computation of the CGI score is simple, requiring only three pieces of data: (1) the total volume irradiated to the prescription isodose level, (2) the volume of the target, and (3) the total volume irradiated at half of the prescription isodose level.

MIRD Pamphlet No 19: absorbed fractions and radionuclide S values for six age-dependent multiregion models of the kidney.

Unlabelled: As one of the major organs of the excretory pathway, the kidneys represent a frequent source of radiopharmaceutical uptake in both diagnostic and therapeutic nuclear medicine. The unique organization of the functional tissues of the organ ensures transient changes in suborgan localization of renal activity. Current single-region dosimetric models of the kidneys, however, force the assumption of a uniform distribution of radioactivity across the entire organ.

Dosimetry of high dose skeletal targeted radiotherapy (STR) with 166Ho-DOTMP.

A study was undertaken to determine the maximum tolerated dose of (166)Ho-DOTMP that could be administered safely, without negatively impacting marrow re-engraftment, in patients with multiple myeloma treated with melphalan prior to transplant. Ho-166 DOTMP is a tetraphosphonate that localizes rapidly to bone surface. The Ho-166 physical half-life is 26.

Voxeldoes: a computer program for 3-D dose calculation in therapeutic nuclear medicine.

A computer program, VoxelDose, was developed to calculate patient specific 3-D-dose maps at the voxel level. The 3-D dose map is derived in three steps: (i) The SPECT acquisitions are reconstructed using a filtered back projection method, with correction for attenuation and scatter; (ii) the 3-D cumulated activity map is generated by integrating the SPECT data; and (iii) a 3-D dose map is computed by convolution (using the Fourier Transform) of the cumulated activity map and corresponding MIRD voxel S values. To validate the VoxelDose software, a Liqui-Phil abdominal phantom with four simulated organ inserts and one spherical tumor (radius 4.

Ultrasound-guided extracranial radiosurgery: technique and application.

Purpose: Stereotactic radiosurgery is an effective treatment modality for many intracranial lesions, but target mobility limits its utility for extracranial applications. We have developed a new technique for extracranial radiosurgery based on optically guided three-dimensional ultrasound (3DUS). The 3DUS system provides the ability to image the target volume and critical structures in real time and determine any misregistration of the target volume with the linear accelerator.

Evolution and status of bone and marrow dose models.

Investigations at the University of Leeds under the direction of F.W. Spiers in the early 1960s through the late 1970s established the first comprehensive assessment of marrow dose conversion factors (DCFs) for beta-emitting radionuclides within the volume or on the surface of trabecular bone.

Commissioning and quality assurance of an optically guided three-dimensional ultrasound target localization system for radiotherapy.

Recently, there has been proliferation of image-guided positioning systems for high-precision radiation therapy, with little attention given to quality assurance procedures for such systems. To ensure accurate treatment delivery, errors in the imaging, localization, and treatment delivery processes must be systematically analyzed. This paper details acceptance tests for an optically guided three-dimensional (3D) ultrasound system used for patient localization.

Comparisons of point and average organ dose within an anthropomorphic physical phantom and a computational model of the newborn patient.

Pediatric radiographic examinations yield medical benefits and/or diagnostic information that must be balanced against potential risk from patient radiation exposure. Consequently, clinical tools for measuring internal organ dose are needed for medical risk assessment. In this study, a physical phantom and Monte Carlo simulation model of the newborn patient were developed based upon their stylized mathematical expressions (ORNL and MIRD model series).