Dysregulated zinc homeostasis and microadenomas in the anterior pituitary: pathological insights into suicide risk.

Background: Suicide is a significant public health problem influenced by various risk factors, including dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis. Zinc (Zn), essential for pituitary function in hormone synthesis and release, has been linked to suicide, with studies noting reduced serum levels and altered brain transport mechanisms. Despite Zn's crucial role in pituitary function and its involvement in suicidal behavior, information on pituitary Zn in suicide is scarce. Tumor cells modify Zn dynamics in tissues, and a previous report suggests microadenomas in the anterior pituitary as a risk factor for suicide. Methods: Histopathological analysis with hematoxylin-eosin stain and histochemical techniques to assess Zn homeostasis were carried out on anterior pituitary postmortem samples from 14 suicide completers and 9 non-suicidal cases. Results: Pituitary microadenomas were identified in 35% of suicide cases and none in the non-suicidal cases. Furthermore, compartmentalized Zn (detected via dithizone reactivity), but not free Zn levels (detected via zinquin reactivity), was lower in the suicide cases compared to the non-suicidal group. Conclusion: This is the first report of a potential association between disrupted Zn homeostasis and microadenomas in the anterior pituitary as a feature in suicide and provides critical insights for future neuroendocrine Zn-related research.

Removal of arsenic(V) using pure zeolite (PZ) and activated dithizone zeolite (ADZ) from aqueous liquids: application to green analytical chemistry.

The primary aim of the present investigation was to evaluate the efficiency of pure zeolite and activated dithizone zeolite for arsenic(V) removal from aqueous solutions. The analytical eco-scale and analytical greenness for sample preparation results confirm that the proposed method is environmentally friendly. Zeolite adsorbents were characterized and tested for their ability to adsorb arsenic(V) from wastewater. Our study delved into arsenic(V) sorption behavior on pristine and activated zeolites. Through steady-state experiments using pure zeolite and activated dithizone zeolite, we examined the sorption of arsenic from aqueous solutions. We optimized operational parameters, including pH, adsorbent dosage, contact time, and arsenic(V) concentration. Our findings revealed that the Langmuir and Freundlich adsorption isothermal models were highly influential in fitting the experimental data, resulting in statistically significant outcomes. This study highlights the potential of zeolites as outstanding adsorbents for removing arsenic(V) from aqueous solutions. The calculated maximum adsorption capacity (qmax) of pure zeolite and activated dithizone zeolite was 18.2 and 21.1(mg/g), respectively, with R2 = 0.999. According to Freundlich's linear model, the experimental isothermal data indicated that activated dithizone zeolite has a higher value of kf constant and a lower value of the 1/n constant than that obtained for pure zeolite. These results imply favorable adsorption of arsenic(V) on activated dithizone zeolite.

Reducing lead uptake by plants as a way to lead-free food.

In this research, an attempt was made to produce safe food from lead-contaminated soil. It was assumed that an increased amount of calcium (Ca) in plants would prevent them from lead (Pb) uptake. A new-generation agricultural product - an activator of Ca transport in plants "InCa" (from Plant Impact) - was used. The study was conducted on several crop species, Cucumis sativus L., Linum usitatissimum L., Medicago sativa L. and Solanum lycopersicum L., cultivated in mineral medium. The leaves were sprayed with InCa activator while the roots received Pb from the substrate in the form of Pb(NO3)2 dissolved in the medium. It was shown that spraying the leaves with InCa reduced Pb concentration in the roots of S. lycopersicum to 73%, in C. sativus to 60%, and in L. usitatissimum to 57%. Finally, it was found that foliar application of InCa reduced the concentration of Pb in plant roots by 53%, and in plant shoots by 57% (on average by about 55%). These observations were confirmed using histochemical and electron microscopy techniques. It was shown that one of the InCa activator components - Ca(NO3)2 - is responsible for such effects. This result was verified by using another experimental method - the Allium epidermis test. Visualization of Pb in epidermal cells of Allium cepa. L. using the Leadmium™Green fluorescent probe (confocal microscopy) showed a reduction in the amount of Pb that entered the epidermal cells after the application of the tested solutions. For the first time, it was shown that it is possible to reduce Pb uptake by plants by up to 55%. In the future, this offers the possibility of developing a foliar calcium preparation aimed at lowering the concentration of Pb in plants and thereby reducing the amount of Pb in the food chain.

Durable Nanocellulose-Stabilized Emulsions of Dithizone/Chloroform in Water for Hg2+ Detection: A Novel Approach for a Classical Problem.

The use of dithizone (DTZ) for colorimetric heavy-metal detection is approximately one century old. However, its pending stability issues and the need for simple indicators justify further research. Using cellulose nanofibers, we attained DTZ-containing emulsions with high stability. These emulsions had water (at least 95 wt %) and acetic acid (1-8 mL/L) conforming the continuous phase, while dispersed droplets of diameter <1 µm contained chloroform-solvated DTZ (3 wt %). The solvation cluster was computed by molecular dynamics simulations, suggesting that chloroform slightly reduces the dihedral angle between the two sides of the thiocarbazone chain. Nanocellulose concentrations over 0.2 wt % sufficed to obtain macroscopically homogeneous mixtures with no phase separation. Furthermore, the rate of degradation of DTZ in the nanocellulose-stabilized emulsion did not differ significantly from a DTZ/chloroform solution, outperforming DTZ/toluene and DTZ/acetonitrile. Not only is the emulsion readily and immediately responsive to mercury(II), but it also decreases interferences from other ions and from natural samples. Unexpectedly, neither lead(II) nor cadmium(II) triggered a visual response at trace concentrations. The limit of detection of these emulsions is 15 µM or 3 mg/L, exceeding WHO limits for mercury(II) in drinking water, but they could be effective at raising alarms.

Enhancement of olfaction by femtomolar concentrations of zinc ions.

Zinc is recognized as an important element for olfaction. Zinc nanoparticles enhance olfaction in response to odors; however, the mechanisms underlying this action remain unknown. Herein, the effect of zinc on olfactory receptors was deduced using electro-olfactogram (EOG) responses recorded from the isolated olfactory mucosae of bullfrogs (Rana catesbeiana) following the administration or chelation of zinc ions. Menthone and n-amyl acetate were used as odorants, whereas forskolin (an adenylate cyclase activator) and cholera toxin (a Gαolf activator) were used as intracellular signal transduction activators. The EOG responses provoked by the odorants and cholera toxin were suppressed by dithizone-mediated zinc ion chelation, and the EOG responses were recovered by administering non-chelated zinc. However, the EOG response to forskolin was not suppressed by dithizone. In contrast, the addition of femtomolar concentrations of zinc ions enhanced the EOG responses. The above-mentioned effects on EOG responses were examined by changing the concentration of zinc ions but not zinc nanoparticles. The results of this study suggest that Gαolf alone or both olfactory receptors and Gαolf likely require zinc ions for their activation.

Supramolecular solvent-based liquid phase extraction of antimony prior to spectrophotometric quantification.

Antimony (Sb) is highly hazardous to human health even in minute concentration. Therefore, its accurate and precise determination in the real environmental samples is of immense importance. In this work for the first time, UV-Vis spectrophotometric method was developed for the quantification of Sb(III) from water samples using supramolecular solvent (undecanol-tetrahydrofuran)-based extraction. The maximum absorption wavelength for antomony-diathizone complex was found to be 590 nm having molar absorptivity of 3.1 × 104 L.mol.cm-1. Factors affecting extraction efficiency like solution sample volume, amount of chelating agent, pH, matrix effect, and type and volume of supramolecular solvent were determined and optimized. Analytical parameters like limit of detection (0.19 µg L-1), limit of quantification (0.62 µg L-1), pre-concentration factor (15), enhancement factor (15), and relative standard deviation for 8 successive analysis (0.8%) were calculated under optimized experimental conditions. The method was applied to real water samples like tap water of laboratory, waste water from Kohat hospitals, and dam water (Tanda dam Kohat) with quantitative addition recovery (94-100%).

Selected organic dyes (carminic acid, pyrocatechol violet and dithizone) sensitized metal (silver, neodymium) doped TiO2/ZnO nanostructured materials: A photoanode for hybrid bulk heterojunction solar cells.

A photoactive nanohybrid material consisting of pyrocatechol violet, carminic acid and dithizone dyes functionalized silver and neodymium-doped TiO2/ZnO nanostructured materials is reported here, as photoactive blend, for solid-state dye sensitized solar cell. First of all we synthesized metals (silver, neodymium) doped (TiO2) Titanium oxide nanoparticles and their nanocomposites (TiO2/ZnO, M-TiO2/ZnO) using the sol-gel and reflux technique, respectively. The synthesized samples were then characterized by UV-Visible spectroscopy, X-Ray diffraction Analysis (XRD), Scanning electron microscopy (SEM), Energy dispersive X-Ray Analysis (EDX), and Fourier Transform infrared spectroscopy (FTIR). Optical studies were done through UV-Visible spectroscopy and the absorption spectra were used to calculate band gaps. The value of the energy gap for TiO2 nanoparticles is 3.10 eV which was gradually tuned to 2.47 eV after incorporating metals (Ag and Nd) and forming respective nanocomposites. X-Ray diffraction Analysis (XRD) patterns revealed the purity and crystallinity in samples. Scanning electron microscopy (SEM) confirmed the irregular morphology (nanorods and spherical shaped) of ZnO and TiO2 nanostructures respectively. The elemental composition of nanomaterials was successfully investigated using energy dispersive X-ray analysis (EDX). In the absence of any impurities, Fourier Transform infrared spectroscopy (FTIR) was used to identify the functional groups in synthesized material. For device fabrication, a solid-state electrolyte, P3HT, a hole conducting polymer was used. Characterization of fabricated solar cells was done using I-V measurements. Under simulated solar irradiation, the DSSC based on pyrocatechol violet sensitized neodymium doped TiO2/ZnO nanohybrid materials exhibited the best PCE (power conversion efficiency) of 2.38 % and significantly improved Jsc (short circuit current density) of 15.68 mA/cm2 as compared to carminic acid and dithizone in photovoltaic measurements. The improved power conversion efficiency of this device is ascribed to the particle size, increased dye adsorption, increased surface area and thus improved short circuit current density (Jsc).

Simple and sensitive method for the determination of methylmercury in hair using thin-layer chromatography with thermal decomposition gold amalgamation atomic absorption spectrophotometry.

An improved method is described for the determination of methylmercury (MeHg) in human hair that is based on thin-layer chromatography and thermal decomposition gold amalgamation atomic absorption spectrophotometry. The dithizone extraction and application procedure of this technique were optimized, thus improving its sensitivity and robustness and enabling the use of less toxic solvents than other approaches. The limit of detection was 0.18 ng MeHg (as Hg), corresponding to 0.018 mg MeHg kg-1 of hair relative to a 10 mg sample. This method is appropriate for detecting MeHg in hair at the approximate reference dose level established by the United States Environmental Protection Agency.

Simple and high-sensitivity colorimetric analysis of cadmium using homogeneous liquid-liquid extraction.

Colorimetric determination with dithizone (diphenylthiocarbazone) is a simple method that has been applied to analyze cadmium (Cd) ions in water. However, determining concentrations close to the environmental standard value (3 µgL-1) using this method is difficult because of its low sensitivity. Herein, we exploited the phase separation phenomenon to generate a small amount of the extraction phase by adding a mixture of 2-propanol and a small amount of chloroform to a water sample, as a pre-concentration method for the Cd(II) ions. The obtained Cd(II)-dithizone complex was successfully extracted into this phase. We then constructed a simple and highly sensitive colorimetric analysis method for the ppb level of Cd(II) using this phase separation technique.

Coordination regulated pyrolysis synthesis of ultrafine FeNi/(FeNi)9S8 nanoclusters/nitrogen, sulfur-codoped graphitic carbon nanosheets as efficient bifunctional oxygen electrocatalysts.

Design of advanced carbon nanomaterials with high-efficiency oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activities is still imperative yet challenging for searching green and renewable energies. Herein, we synthesized ultrafine FeNi/(FeNi)9S8 nanoclusters encapsulated in nitrogen, sulfur-codoped graphitic carbon nanosheets (FeNi/(FeNi)9S8/N,S-CNS) by coordination regulated pyrolyzing the mixture of the metal precursors, dithizone and g-C3N4 at 800 °C. The as-prepared FeNi/(FeNi)9S8/N,S-CNS exhibited distinct electrocatalytic activity and stability for the ORR with positive onset (Eonset) and half-wave (E1/2) potentials (Eonset = 0.97 V; E1/2 = 0.86 V) and OER with the small overpotential (η = 283 mV) at 10 mA cm-2 in the alkaline media, outperforming commercial Pt/C and RuO2 catalysts. This research provides some constructive guidelines for preparing efficient, low-cost and stable nanocatalysts for electrochemical energy devices.

Dithizone-functionalized C18 online solid-phase extraction-HPLC-ICP-MS for speciation of ultra-trace organic and inorganic mercury in cereals and environmental samples.

A simple and efficient dithizone-functionalized solid-phase extraction (SPE) procedure, online coupled with high-performance liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry, was developed for the first time for enrichment and determination of ultra-trace mercury (Hg) species (inorganic divalent Hg (Hg(II)), methylmercury (CH3Hg(II)) and ethylmercury (C2H5Hg(II)) in cereals and environmental samples. In the proposed method, functionalization of the commercial C18 column with dithizone, enrichment, and elution of the above Hg species can be completed online with the developed SPE device. A simple solution of 2-mercaptoethanol (1% (V/V)) could be used as an eluent for both the SPE and HPLC separation of Hg species, significantly simplifying the method and instrumentation. The online SPE method was optimized by varying dithizone dose, 2-mercaptoethanol concentration, and sample volume. In addition, the effect of pH, coexisting interfering ions, and salt effect on the enrichment was also discussed. Under the optimized conditions, the detection limits of Hg species for 5 mL water sample were 0.15 ng/L for Hg(II), 0.07 ng/L for CH3Hg(II), and 0.04 ng/L for C2H5Hg(II) with recoveries in the range of 85%-100%. The developed dithizone-functionalized C18 SPE column can be reused after a single functionalization, which significantly simplifies the enrichment step. Moreover, the stability of Hg species enriched on the SPE column demonstrated its suitability for field sampling of Hg species for later laboratory analysis. This environment-friendly method offers a robust tool to detect ultra-trace Hg species in cereals and environmental samples.

Magnetic Dispersive Solid Phase Extraction Using Recycled-graphite for GO-Fe3O4-dithizone Composite Combined with FAAS for Determination of Lead in Environmental Samples.

Magnetic dispersive solid phase extraction (MdSPE) was developed to determine the concentration of lead (Pb) in real water samples, while graphene oxide-magnetite-dithizone (GO-Fe3O4-DTZ) from the used graphite tubes (recycled graphite) of electrothermal technique was simply employed as a new sorbent to improve extraction efficiency, separated by external magnetic field and analyzed with FAAS. The synthesized sorbent was evaluated for its surface property, functional group and surface morphology by Zeta potential, Fourier transform infrared spectrophotometer (FTIR), and scanning electron microscope (SEM), respectively. The relevant measurement parameters, such as pH, extraction time, type and concentration of eluent, sample volume and reusability, were optimized. Under the optimal conditions, preconcentration factor was 13.33. The limit of detection (LOD) and limit of quantitation (LOQ) obtained were 0.070 and 0.23 mg/L, respectively. The relative standard deviation (%RSD) was 3.41%. Recovery values were 90.1 - 123%. In addition, the robustness of the method was affirmed in terms of tolerance limit obtained from interference studies.

An Efficient and Stable Perovskite Solar Cell with Suppressed Defects by Employing Dithizone as a Lead Indicator.

The defects in perovskite films are one of the most non-negligible factors that can attenuate the performances of perovskite solar cell. This work fabricates defect-reduced perovskite film by using the lead indicator (dithizone) as an additive of perovskite functional layer. The dithizone can retard the crystallization rate of perovskite films, passivate the defects, and enhance the structure stability of perovskite by coordinating with lead atoms. As a result, the device doped with dithizone yields outstanding power conversion efficiency and stability.

A sensitive fluorescent probe based on dithizone-capped ZnS quantum dots for quercetin determination in biological samples.

A simple turn on/off fluorescence approach based on dithizone-capped ZnS quantum dots (ZnS@DZ QDs) with the help of lead ions as a fluorescent probe for the quantitative determination of quercetin is reported. The interaction of lead ions with dithizone led to the formation of a rigid structure on the surface of ZnS@DZ QDs and turned on the fluorescence intensity of the QDs. After addition of quercetin to this probe and interaction with lead ions, the fluorescence emission turned off. Concerning the quenching fluorescence intensity of ZnS@DZ QDs/Pb2+ QDs probe induced by the target, under the optimum conditions, the probe enabled detection of quercetin in the concentration range from 0.54 µM to 21.7 µM with a correlation coefficient of 0.993 and detection limit of 0.25 µM. The present probe was applied successfully to the determine quercetin as a nutritional biomarker in human serum and 24-h urine samples.

Preconcentration of mercury(II) using a magnetite@carbon/dithizone nanocomposite, and its quantification by anodic stripping voltammetry.

A new adsorbent is described that consists of a magnetite@carbon/dithizone nanocomposite. It was characterized using energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and field emission scanning electron microscopy. The magnetic sorbent is shown to be a viable material for the preconcentration of mercury(II) before its quantification by differential pulse anodic stripping voltammetry. The effects of pH value, eluent, adsorbent amount, sample volume, and adsorption/desorption time were optimized. The calibration plot extends from 0.25 to 30 ng.mL-1, and the detection limit is 27 pg.mL-1. The preconcentration factor and intra-day and inter-day relative standard deviations are 100, 3.8, and 4.5%, respectively, for six measurements at 5 ng.mL-1 concentrations of mercury(II). The method was validated by the analysis of the certified reference material NIST SRM 1566b, and successfully applied to the preconcentration and quantification of mercury(II) in industrial wastewaters and spiked water samples. Graphical abstractSchematic representation of magnetic solid-phase extraction of mercury(II) ion by dithizone-modified Fe3O4@C nanocomposite (Fe3O4@C/Dz NC) before its quantification by anodic stripping voltammetry (ASV).

In vitro differentiation of single donor derived human dental mesenchymal stem cells into pancreatic ß cell-like cells.

The present study was carried out to investigate and compare the in vitro differentiation potential of mesenchymal stem cells (MSCs) isolated from human dental tissues (pulp, papilla, and follicle) of the same donor. MSCs were isolated from dental tissues (pulp, papilla, and follicle) following digestion method and were analyzed for the expression of pluripotent markers and cell surface markers. All three types of MSCs were evaluated for their potential to differentiate into mesenchymal lineages. Further, the MSCs were differentiated into pancreatic ß cell-like cells using multistep protocol and characterized for the expression of pancreatic lineage specific markers. Functional properties of differentiated pancreatic ß cell-like cells were assessed by dithizone staining and glucose challenge test. All three types of MSCs showed fibroblast-like morphology upon culture and expressed pluripotent, and mesenchymal cell surface markers. These MSCs were successfully differentiated into mesenchymal lineages and transdifferentiated into pancreatic ß cell-like cells. Among them, dental follicle derived MSCs exhibits higher transdifferentiation potency toward pancreatic lineage as evaluated by the expression of pancreatic lineage specific markers both at mRNA and protein level, and secreted higher insulin upon glucose challenge. Additionally, follicle-derived MSCs showed higher dithizone staining upon differentiation. All three types of MSCs from a single donor possess similar cellular properties and can differentiate into pancreatic lineage. However, dental follicle derived MSCs showed higher potency toward pancreatic lineage than pulp and papilla derived MSCs, suggesting their potential application in future stem cell based therapy for the treatment of diabetes.

High Efficiency Mercury Sorption by Dead Biomass of Lysinibacillus Sphaericus-New Insights into the Treatment of Contaminated Water.

Mercury (Hg) is a toxic metal frequently used in illegal and artisanal extraction of gold and silver which makes it a cause of environmental poisoning. Since biosorption of other heavy metals has been reported for several Lysinibacillus sphaericus strains, this study investigates Hg removal. Three L. sphaericus strains previously reported as metal tolerant (CBAM5, Ot4b31, and III(3)7) were assessed with mercury chloride (HgCl2). Bacteria were characterized by scanning electron microscopy coupled with energy dispersive spectroscopy (EDS-SEM). Sorption was evaluated in live and dead bacterial biomass by free and immobilized cells assays. Hg quantification was achieved through spectrophotometry at 508 nm by reaction of Hg supernatants with dithizone prepared in Triton X-114 and by graphite furnace atomic absorption spectroscopy (GF-AAS). Bacteria grew up to 60 ppm of HgCl2. Non-immobilized dead cell mixture of strains III(3)7 and Ot4b31 showed a maximum sorption efficiency of 28.4 µg Hg/mg bacteria during the first 5 min of contact with HgCl2, removing over 95% of Hg. This process was escalated in a semi-batch bubbling fluidized bed reactor (BFB) using rice husk as the immobilization matrix leading to a similar level of efficiency. EDS-SEM analysis showed that all strains can adsorb Hg as particles of nanometric scale that can be related to the presence of S-layer metal binding proteins as shown in previous studies. These results suggest that L. sphaericus could be used as a novel biological method of mercury removal from polluted wastewater.

Cadmium tolerance, distribution, and accumulation in Taraxacum ohwianum Kitam. as a potential Cd-hyperaccumulator.

Strong capacity of cadmium tolerance and bioaccumulation in dandelions was revealed under 6-month treatments with different Cd concentrations (0, 50, 80, 100, 120 mg/kg). At the lowest Cd concentration (10 mg/kg), bioconcentration factors (BCF) of dandelions were greater than 1 and the transfer coefficient reached the maximum value of 0.74. At the Cd concentration of 100 mg/kg, the biomass of root was the greatest, the aboveground biomass reached 1.73 g/plant DW, which was 1.3 times of the blank control. Cd content in the leaves reached 100.11 mg/kg DW, which was in line with the threshold value (100 mg/kg) of Cd hyperaccumulators. In the roots of dandelions, Cd was mainly stored in the laticifer groups of phloem and cork, and xylem. The important Cd detoxification mechanism of plants included the combination of Cd and cork cell walls, the combination of Cd and xylem parenchyma cells, the combination of Cd and cell inclusions and precipitation in the laticifer. In leaves and scapes, Cd was preferentially accumulated in laticifer, epidermis cell, parenchyma cell inclusions and epidermis appendages, such as non-glandular hairs, etc., indicating that these sites played an important role in detoxification of heavy metals.

White-light emissive upconversion nanoparticles for visual and colorimetric determination of the pesticide thiram.

The authors describe the use of white-light emitting upconversion nanoparticles (WL-UCNPs) for visual detection of the pesticide thiram. The method is demonstrated to undergo a better discernable color change upon target binding. The WL-UCNPs are modified with the lead(II)-dithizone complex which acts as the energy acceptor and recognition unit. This leads to quenching of the blue (475 nm) and green (545 nm) emissions of the WL-UCNPs, while the red emission (650 nm) remains unaffected. Upon addition of thiram, the quenched emissions are recovered, with a linear signal increase in the range from 2 nM to 20 nM of thiram and a limit of detection of 0.26 nM. The nanoprobe was further integrated into a test paper for visual detection. The concentration-dependent color change that varies from red to cyan and bluish violet and then to white can be visually distinguished. Graphical abstract Schematic presentation of a white-light emissive upconversion nanoparticle based test paper for color-discernable detection of the pesticide thiram. The test stripe exhibits a concentration-dependent color variation spanning from red, cyan, to bluish violet, and at last to white.

Preparation of highly selective magnetic cobalt ion-imprinted polymer based on functionalized SBA-15 for removal Co2+ from aqueous solutions.

In this research, a novel magnetic cobalt ion imprinted adsorbent (Co(II)-MIIP) was synthesized by use of magnetic SBA-15 core-shell. It was functionalized by dithizone, and after identification by various techniques was used for removal of cobalt from aquatic systems. The uptake of cobalt proceeded very fast and achieved to equilibration within 5 min at which 74 mg g-1 of cobalt was adsorbed at pH = 8 with adsorbent dose of 0.15 g. The ion imprinted sorbent exhibited good selectivity towards cobalt ions. Separation and recovery of the used sorbent was carried out respectively by use of magnetic field and by use of HNO3 (0.1 M), and 85% of the initial capacity was obtained after seven 7 regeneration cycles. Different isotherm models, and error analysis were used to evaluate the experimental data. Thermodynamic, and kinetic evaluations showed that sorption process was endothermic, and described by second order kinetic model (R2 > 0.99). The equilibrium was established within five min.