Search Results (176)

Airborne iodine-131 plays a pivotal role in both nuclear medicine and nuclear safety due to its radiotoxicity, volatility, and affinity for the thyroid gland. Although the total exhaled activity after medical I-131 therapy is minimal, over 95% of this activity appears in volatile organic forms, which evade standard filtration and reflect metabolic pathways of iodine turnover. Our experimental work in patients and mice confirms the metabolic origin of these species, modulated by thyroidal function. In nuclear reactor environments, both under routine operation and during accidents, organic iodides such as [¹³¹I]CH₃I have also been identified as major airborne components, often termed “penetrating iodine” due to their low adsorption to conventional filters. This review compares the molecular speciation, environmental persistence, and dosimetric impact of airborne I-131 across clinical, technical, and accidental release scenarios. While routine reactor emissions yield negligible doses (<0.1 µSv/year), severe nuclear incidents like Chernobyl and Fukushima have resulted in significant thyroid exposures. Doses from these events ranged from tens of millisieverts to several Sieverts, particularly in children. We argue that a deeper understanding of chemical forms is essential for effective risk assessment, filtration technology, and emergency preparedness. Iodine-131 exemplifies the dual nature of radioactive substances: in nuclear medicine its radiotoxicity is therapeutically harnessed, whereas in industrial or reactor contexts it represents an unwanted hazard. The same physicochemical properties that enable therapeutic efficacy also determine, in the event of uncontrolled release, the range, persistence, and the potential for unwanted radiotoxic exposure in the general population. In nuclear medicine, exhaled activity after radioiodine therapy is minute but largely organically bound, reflecting enzymatic and metabolic methylation processes. During normal reactor operation, airborne iodine levels are negligible and dominated by inorganic vapors efficiently captured by filtration systems. In contrast, major accidents released large fractions of volatile iodine, primarily as elemental [¹³¹I]I₂ and organically bound iodine species like [¹³¹I]CH₃I. The chemical nature of these compounds defined their atmospheric lifetime, transport distance, and deposition pattern, thereby governing the thyroid dose to exposed populations. Chemical speciation is the key determinant across all scenarios. Exhaled iodine in medicine is predominantly organic; routine reactor releases are negligible; severe accidents predominantly release elemental and organic iodine that drive environmental transport and exposure. Integrating these domains shows how chemical speciation governs volatility, mobility, and bioavailability. The novelty of this review lies not in introducing new iodine chemistry, but in the systematic comparative synthesis of airborne radioiodine speciation across medical therapy, routine nuclear operation, and severe accident scenarios, identifying chemical form as the unifying determinant of volatility, environmental transport, and dose. Full article

Background/Objective: Acute and chronic pain affect millions of individuals, yet there are currently no molecular imaging tools to directly assess pain-related mechanisms in the central nervous system (CNS). The voltage-gated sodium channel Na_V1.8 plays a pivotal role in neuropathic pain by increasing the excitability of nociceptive neurons following nerve injury or inflammation. In this work, we aimed to develop a novel positron emission tomography (PET) imaging probe for Na_V1.8 to facilitate noninvasive quantification of this target in the CNS and thereby advance our understanding of pain neurobiology. Methods: We selected the compound suzetrigine, a U.S. FDA-approved, highly selective non-opioid Na_V1.8 inhibitor, as the first candidate for a Na_V1.8-targeted PET tracer. The compound was first assessed using in silico docking and CNS multiparameter optimization (MPO) analysis to evaluate target binding and predicted brain penetrability. Radiolabeling was accomplished by O-methylation with [¹¹C]methyl iodide to yield [¹¹C]suzetrigine without structural modification. The tracer was then evaluated using in vitro binding assays, including autoradiography and saturation binding on rat brain tissues, to determine binding parameters (K_D, B_max), and using in vivo PET imaging in rats to assess brain uptake, time–activity curves (TACs), and tracer behavior under baseline and pretreatment conditions. Pretreatment was performed with unlabeled suzetrigine, the P-glycoprotein (P-gp) inhibitor verapamil, and the heterologous Na_V1.8 inhibitor A-803467. Results: In silico docking demonstrated favorable binding of suzetrigine to the Na_V1.8 active site, and the calculated CNS MPO score (>3.5) suggested adequate brain penetration. Radiochemical synthesis of [¹¹C]suzetrigine via O-methylation yielded a high decay-corrected radiochemical yield (19.2 ± 2.7%, n = 3), excellent purity (>98%, n = 3), and moderate molar activity (62.9 ± 51.8 MBq/nmol, n = 3). Autoradiography on rat brain tissue confirmed saturable and selective binding of [¹¹C]suzetrigine to Na_V1.8. Saturation binding assays revealed a B_max = 93 fmol/mg and a K_D = 0.1 nM, supporting the imageability of Na_V1.8 in the brain using this tracer. In vivo PET imaging in rats demonstrated rapid and sufficient brain uptake but revealed unexpected tracer behavior: signal intensity markedly increased following pretreatment with either unlabeled suzetrigine or the P-gp inhibitor verapamil, and showed a slight increase after pretreatment with the heterologous Na_V1.8 inhibitor A-803467. Detailed analysis of PET images, TACs, and normalized area-under-curve (AUC) values indicated that these atypical uptake patterns were primarily attributable to P-gp-mediated effects, although additional factors may also contribute. Conclusions: [¹¹C]Suzetrigine exhibits high affinity, good brain uptake, and selective target engagement in vitro, supporting its potential as a first-in-class Na_V1.8-PET tracer. However, in vivo performance is confounded by P-gp-mediated efflux and possibly other mechanisms that limit accurate quantification of Na_V1.8 in the living brain. These findings underscore the critical role of efflux transporters in CNS radiotracer development and highlight the need for design strategies that mitigate P-gp interaction when targeting ion channels in the brain. Future studies will include imaging under constant P-gp inhibition, arterial blood sampling for radiometabolite analysis and full kinetic modeling, and evaluation in non-human primates to assess translational feasibility. Full article

The synthesis of the first 2-alkyl-1,2,3-selenadiazol-2-ium salt is reported. Extensive spectroscopic characterization including Se-NMR was performed and the results are compared with those of the known 3-ium isomer. The yellow compound crystallizes in blocks as well as in columns. The crystal structures of both types are solved by X-ray diffraction and give final proof of the molecular structure. Full article

Using an environmentally friendly approach, we successfully synthesized an asymmetric monomethine cyanine dye, 7-chloro-1-ethyl-4-((3-ethylbenzo[d]thiazol-2(3H)-ylidene)methyl) quinolin-1-ium iodide, named CHLoris (CHL), via a modified Knoevenagel-type condensation. The reaction was carried out mechanochemically in an ethanol–water medium using 1-ethyl-2-methylbenzothiazolium iodide and 4,7-dichloro-1-ethylquinolin-1-ium iodide in the presence of sodium carbonate as a base and catalytic amounts of Hünig’s base. The UV/VIS absorption spectra of CHL in both the buffer solution and ethanol revealed the formation of aggregates in aqueous media. Density Functional Theory (DFT) and Time-Dependent DFT (TDDFT) calculations were employed to support the experimental findings further and provide insights into the self-association behavior of CHL in an aqueous solution. The photophysical properties of the dye were examined in the presence of DNA and RNA, and its performance was compared to that of the commercial dye Thiazole Orange (TO) under identical conditions. The results show that CHL is more sensitive towards RNA. Full article

A synthetic methodology of the CuAAC “click” approach was exploited for the construction of 1,2-azolyltriazole quinine derivatives by the reaction of O-propargylquinine with azidomethyl-1,2-azoles in methanol. Quinine–piperidine and quinine–anabasine conjugates were obtained using a chloroacetate linker by reacting quinine chloroacetate with piperidine or anabasine in a diethyl ether medium. Cinchophene ester was obtained by the acylation of quinine with cinchophen acid chloride in methylene chloride. The antibacterial, fungicidal, analgesic and cytotoxic properties of the obtained compounds were examined. Full article

Candidiasis arises from the proliferation of Candida species in the human body, especially in individuals with compromised immune systems. Efficient therapeutic management of candidiasis is often hampered by the limited availability of potent antifungal drugs and the emergence of drug-resistant strains. We have previously identified the N-[(4-sulfamoylphenyl)methyl][1,1′-biphenyl]-4-carboxamide to have fungistatic and fungicidal properties, likely due to the hydrophobic biphenyl–chemical features affecting the structural organization of Candida spp. cell membrane. Here, we designed and synthesized a novel series of twelve 5-arylfuran-2-carboxamide derivatives bearing a new hydrophobic tail as bioisosteric replacement of the diphenyl fragment. Its antifungal effectiveness against C. albicans, C. glabrata, and C. parapsilosis, including ATCC and clinically isolated strains, was assessed for all compounds. The most active compound was N-benzyl-5-(3,4-dichlorophenyl)furan-2-carboxamide (6), with fungistatic and fungicidal effects against C. glabrata and C. parapsilosis strains (MIC = 0.062–0.125 and 0.125–0.250 mg/mL, respectively). No synergistic effects were observed when combined with fluconazole. Interestingly, fluorescent microscopy analysis after staining with SYTO 9 and propidium iodide revealed that compound 6 affected the cell membrane integrity in C. albicans strain 16. Finally, carboxamide 6 exhibited a dose-dependent cytotoxicity on erythrocytes, based on assessing the LDH release. Full article

The increasing demand for high-performance energy storage devices has stimulated interest in advanced electrolyte materials. Among them, ionic liquids ($\mathrm{I}\mathrm{L}\mathrm{s}$) stand out for their thermal stability, wide electrochemical windows, and good ionic conductivity. When doped into polymeric matrices, these ionic liquids form hybrid polymeric electrolytes that synergize the benefits of both liquid and solid electrolytes. This study explores a polymeric electrolyte based on polyethylene oxide ($\mathrm{P}\mathrm{E}\mathrm{O}$) doped with tributylmethylphosphonium iodide $\left(\mathrm{T}\mathrm{M}\mathrm{P}\mathrm{I}\right)$ and ammonium iodide ($\mathrm{N}{\mathrm{H}}_4\mathrm{I}$), focusing on its synthesis, structural and electrical properties, and performance in energy storage devices such as dye-sensitized solar cells and supercapacitors. Strategies to improve its ionic conductivity, mechanical and chemical stability, and electrode compatibility are also discussed, along with future directions in this field. Full article

PFASs are widely present and persistent in the environment, and exposure can occur via multiple pathways. Human and animal PFAS exposures have been associated with alterations in thyroid hormones, hepatotoxicity, and other adverse effects. This study evaluated the subchronic toxicities of four specific PFASs in 90-day oral rat studies. Studies were conducted in male and female Sprague–Dawley rats exposed to PFASs in corn oil via oral gavage. The PFASs studied were 1H,1H,9H-perfluorononyl acrylate (PFNAC), 1H,1H,2H,2H-perfluorohexyl iodide (PFHI), methyl heptafluoropropyl ketone (MHFPK), and 2-chloro-2,3,3,3-tetrafluoropropanoic acid (CTFPA). High doses were 10 mg/kg-day (male) and 30 mg/kg-day (female) for PFNAC, 200 mg/kg-day for PFHI, 300 mg/kg-day for MHFPK, and 30 (male) and 100 mg/kg-day (female) for CTFPA. The four lower doses for each PFAS were spaced at two- or threefold dose increments. The most consistent effect was dose-dependent increases in the relative and absolute liver weights for PFNAC, PFHI, and CTFPA but not for MHFPK. Increased liver weights were correlated with findings of hepatocellular hypertrophy. Increased kidney weights for PFNAC and PFHI were correlated with increased incidence of minimal tubule epithelial hypertrophy (PFNAC) or increased incidence and severity of chronic progressive nephropathy and hyaline droplet accumulation (PFHI). There were no compound-related effects on morbidity and mortality or overt signs of toxicity. Full article

Two new asymmetric monomethine cyanine dyes, featuring dimethoxy quinolinium or methyl quinolinium end groups and benzothiazole or methyl benzothiazole end groups were synthesized. The chemical structures of the two dyes—(E)-6,7-dimethoxy-1-methyl-4-((3-methylbenzo[d]thiazol-2(3H)-ylidene)methyl)quinolin-1-ium iodide (3a) and (E)-4-((3,5-dimethylbenzo[d]thiazol-2(3H)-ylidene)methyl)-1,2-dimethylquinolin-1-ium iodide (3b)—were confirmed through NMR spectroscopy and MALDI-TOF mass spectrometry. A new methodology was developed to study monocationic dyes in the absence of a matrix and cationizing compounds in MALDI-TOF mass experiments. The newly synthesized dyes contain hydrophobic functional groups attached to the chromophore, enhancing their affinity for the hydrophobic regions of nucleic acids within the biological matrix. The dyes’ photophysical properties were investigated in aqueous solutions and DMSO, as well as in the presence of nucleic acids. The dyes exhibit notable aggregachromism in both pure aqueous and buffered solutions. The observed aggregation phenomena were further elucidated using computational methods. Fluorescence titration experiments revealed that upon contact with nucleic acids, the dyes exhibit bioaggregachromism–aggregachromism on the surfaces of the respective biomolecular matrix (RNA or DNA). This bioaggregachromism was further confirmed by CD spectroscopy. Given the pronounced aggregachromism detected, we conclude that the dyes investigated in this study are highly suitable for use as fluorogenic probes in biomolecular recognition techniques. The unique absorption and fluorescence spectra of these dyes make them promising fluorogenic markers for various bioanalytical methods related to biomolecular recognition. Full article

This study outlines the sustainable synthesis of novel hydroxytyrosol (HT) and tyrosol (T) ester derivatives via a Pd-catalyzed alkoxycarbonylation of aromatic iodides. The high sustainability of the process is attributed to the use of (1) a solid carbon monoxide source, Mo(CO)₆, in place of dangerous gaseous CO; (2) a biomass-derived organic solvent, CPME (cyclopentyl methyl ether); (3) naturally occurring hydroxylated compounds, such as HT and T, which could be derived from agricultural waste rather than produced from petroleum-based sources. The method enables the regioselective preparation of various HT and T esters in a short reaction time (4–8 h), under mild temperatures (80 °C), and with moderate-to-excellent yields (62–93%). Moreover, in vitro biological tests have demonstrated that, in addition to the well-known antioxidant properties typical of natural phenolic compounds such as HT and T, some of the newly synthesized derivatives have a safe profile and are effective inhibitors of the α-glucosidase with potential application in the management of hyperglycemia. This synthetic approach offers a promising strategy for exploring biologically relevant chemical space, bridging the gap between natural products and sustainable drug synthesis. Full article

In the recent reports, it is clear that lead-free perovskite materials with low band gaps are desirable candidates for photovoltaic cells. In this regard, it was observed that germanium (Ge) is a less toxic lead-free metal that is significant for the preparation of Ge-based perovskite materials. Ge-based perovskite materials, for example, methyl ammonium germanium iodide (MAGeI₃), cesium germanium iodide (CsGeI₃), and/or formamidinium germanium iodide (FAGeI₃) may be the suitable absorber materials and alternatives towards the fabrication of lead-free photovoltaic cells. In the past few years, few attempts were made to develop FAGeI₃-based perovskite solar cells, but their photovoltaic performance is still under limitations. This is indicating that some significant and effective strategies should be designed and developed for the construction of Ge-based perovskite solar cells. It is believed that optimization of layer thickness, device structure, and selection of a suitable electron transport layer (ETL) may improve the photovoltaic performance of FAGeI₃-based perovskite solar cells. Solar cell capacitance simulation, i.e., SCAPS is one of the promising software programs that can provide significant theoretical findings for the development of FAGeI_3-based perovskite solar cells. The simulation studies via SCAPS may benefit researchers to save their energy and high cost for the optimization process in the laboratories. In this research article, SCAPS was adopted as a simulation tool for the theoretical investigations of FAGeI_3-based perovskite solar cells. The simulation studies exhibited the excellent efficiency of 15.62% via SCAPS. This study proposed the optimized device structure of FTO/TiO₂/FAGeI₃/PTAA/Au with enhanced photovoltaic performance. Full article

The nun moth, Lymantria monacha L. (Linnaeus, 1758), is one of the most important defoliators of coniferous forests in Europe and Asia. In sexual communication, females produce three epoxides and an alkene: (−)-disparlure [(7S,8R)-cis-7,8-epoxy-2-methyloctadecane], (+)-monachalure [(7R,8S)-cis-7,8-epoxyoctadecane], (−)-monachalure [(7S,8R)-cis-7,8-epoxyoctadecane], and their corresponding olefins. This study aimed to develop a green synthesis pathway for all pheromonal components, emphasizing the use of common raw materials, a simplified three-step process, lower costs, and an environmentally friendly approach compared to existing methods. The proposed method introduces a novel synthetic route employing an innovative improvement alkylation step catalyzed by lithium iodide in diglyme. The synthesized compounds were characterized using GC-MS, ¹H NMR, and ¹³C NMR spectroscopy. Six synthetic blends were formulated for field testing, with the goal of identifying the most attractive composition. Field trials demonstrated that a blend with a 10:10:1 ratio of (±)-Disparlure, (±)-Monachalure, and (Z)-2-Methyl-7-octadecene exhibited the highest attraction efficiency. Full article

This study investigated the reactions of 1-alkyl-3-phenylbenzimidazolium salts with Ag₂O. It was found that the selectivity of the reaction products was influenced by the N-alkyl substituent on the azolium ring. For example, treating 1-methyl-3-phenylbenzimidazolium iodide (2) with Ag₂O for 24 h produced the ring-opening formamide derivative N-[2-(phenylamino)phenyl]-N-methylformamide (2b) in an 85% yield. In contrast, the reaction of 1-benzyl-3-phenylbenzimidazolium chloride (3) with Ag₂O under the same conditions yielded the corresponding N-heterocyclic carbene (NHC)–Ag complex (1-benzyl-3-phenylbenzimidazol-2-ylidene) silver(I) chloride (3a) in an 86% yield. Furthermore, the corresponding monodentate NHC–Au complex 2c could be synthesized by allowing 2 to react with AuCl(SMe₂) in the presence of Ag₂O. Full article

The continuous tightening of pharmaceutical regulations forces drug manufacturers to unambiguously characterize the substances related to the active pharmaceutical ingredients (API). Here, we report the synthesis, complete spectroscopic, chromatographic, thermal and computational characterization, as well as in silico prediction of bacterial mutagenicity for two previously reported but never fully characterized impurities of methimazole. Additionally, their structures were analyzed by single-crystal X-ray diffraction. 1-Methyl-(2-methylthio)-1H-imidazole also known as methimazole impurity C, was obtained mainly in the form of the iodide salt (C₅H₉IN₂S) crystallizing in monoclinic space group P2₁/c. The disulfide (2,2′-disulphanylbis(1-methyl-1H-imidazole)), C₈H₁₀N₄S₂) was obtained in yellow form crystallizing in the monoclinic C2/c space group. Full article

A series of new quinazolin-2,4-dione derivatives incorporating amide/eight-membered nitrogen-heterocycles 2a–c, in addition, acylthiourea/amide/dithiolan-4-one and/or phenylthiazolidin-4-one 3a–d and 4a–d. The starting compound 1 was prepared by reaction of 4-(2,4-dioxo-1,4-dihydro-2H-quinazolin-3-yl)-benzoyl chloride with ammonium thiocyanate and cyanoacetic acid hydrazide. The reaction of 1 with strong electrophiles, namely, o-aminophenol, o-amino thiophenol, and/or o-phenylene diamine, resulted in corresponding quinazolin-2,4-dione derivatives incorporating eight-membered nitrogen-heterocycles 2a–d. Compounds 3a–d and 4a–d were synthesized in good-to-excellent yield through a one-pot multi-component reaction (MCR) of 1 with carbon disulfide and/or phenyl isocyanate under mild alkaline conditions, followed by ethyl chloroacetate, ethyl iodide, methyl iodide, and/or concentrated HCl, respectively. The obtained products were physicochemically characterized by melting points, elemental analysis, and spectroscopic techniques, such as FT-IR, ¹H-NMR, ¹³C-NMR, and MS. The antibacterial efficacy of the obtained eleven molecules was examined in vitro against two Gram-positive bacterial strains (Staphylococcus aureus and Staphylococcus haemolyticus). Furthermore, Computer-Aided Drug Design (CADD) was performed on the synthesized derivatives, standard drug (Methotrexate), and reported antibacterial drug with the target enzymes of bacterial strains (S. aureus and S. haemolyticus) to explain their binding mode of actions. Notably, our findings highlight compounds 2b and 2c as showing both the best antibacterial activity and docking scores against the targets. Finally, according to ADMET predictions, compounds 2b and 2c possessed acceptable pharmacokinetics properties and drug-likeness properties. Full article