Hasil untuk "Inorganic chemistry"

Elena Haettig, Aaron Haben, Ralf Kautenburger et al.

<b>Background/Objectives</b>: Alveolar macrophages represent the main path of defense in the peripheral pulmonary tissue, though their role in chronic inflammatory lung diseases shows that their protective function can turn pathological. This study focused on developing a system to passively target the release of the pro-inflammatory cytokine TNF-α through the local delivery of siRNA. <b>Methods</b>: An inhalable aspherical microparticle made up of mesoporous silica nanoparticles, crosslinked by an electrostatic LbL-system embedding the siRNA, was developed. <b>Results</b>: Through testing with the NGI, adequate aerodynamic properties with an MMAD as low as 3.37 µm could be determined, with a GSD as low as 1.46, suggesting a relatively small size distribution even during inhalation. To further understand the interaction of the microrods with the lung parenchyma and the resident cells, the disintegration of the rods in different simulant body fluids, their toxicity, and the cell uptake through dTHP-1 and A549 were observed. This showed slow but continuous disintegration, no toxicity in A549 cells, and high microrod uptake by dTHP-1 cells. To demonstrate the effect of the delivered siRNA on the release of TNF-α, ELISAs were carried out, establishing an inhibitory effect of the siRNA-carrying microcarrier system compared to those without siRNA or loaded with scrambled siRNA. To increase the efficacy of the siRNA, chloroquine as an endosomal escape-enhancing compound was loaded onto the mesoporous silica nanoparticles. This resulted in a significant improvement in siRNA inhibition. <b>Conclusions</b>: The developed formulation is able to reach the targeted structure and inhibit the secretion of TNF-α, with CQ increasing the inhibitory effect of the siRNA.

Katarzyna Szramowiat-Sala, Marta Marczak-Grzesik, Mateusz Karczewski et al.

Abstract Polycyclic aromatic hydrocarbons (PAHs) are hazardous air pollutants with well-documented carcinogenic, mutagenic, and toxic effects. This study investigates the chemical composition and sources of PAHs in Kraków, a city characterized by diverse air quality challenges. PM10 and PM2.5 samples were collected during the winter seasons of 2014 and 2015, enabling a detailed assessment of PAH concentrations and their atmospheric transformations. The results indicate that PAH levels frequently exceeded European Union and World Health Organization limits, with benzo[a]pyrene (BaP) reaching peak concentrations of 38.8 ng m−3 in PM10 and 30.2 ng m−3 in PM2.5, highlighting significant health risks. To determine PAH sources, a chemical-based framework integrating diagnostic ratios, receptor modeling, and backward trajectory analysis was applied. The findings reveal that coal and biomass combustion were dominant PAH contributors, with additional influences from vehicular emissions and industrial activities. The BaP/(BaP + BeP) ratio suggested that PAHs in PM2.5 underwent more atmospheric aging than those in PM10, indicating that finer particles play a crucial role in PAH transport and transformation. Furthermore, correlations with inorganic and organic PM constituents, such as chloride and levoglucosan, underscored the mixed influence of fossil fuel and biomass burning. The study also evaluated the toxicological implications of PAHs, demonstrating that mutagenic activity exceeded toxicity levels, and finer particles posed a greater carcinogenic risk. While the exposure index suggested that short-term exposure remained within acceptable limits, long-term effects require further assessment. Given the complex interplay of emission sources and atmospheric processes, continuous monitoring and targeted mitigation strategies are essential for improving urban air quality.

Elyse A. Schriber, Daniel J. Rosenberg, Daniel W. Paley et al.

Small-molecule serial femtosecond crystallography (smSFX) at XFELs has become a reliable tool for determining structures of new, unknown materials from microcrystalline powders. The use of smSFX has had a considerable impact on metal-organic chalcogenolate (MOCHa) research, where smSFX derived structures have contributed new knowledge on the structure-function relationships in MOCHa compounds and have informed MOCHA synthetic efforts significantly. The vast demand in materials science and chemistry fields for structural techniques that produce high-quality, accurate structures from microcrystalline samples show the impact the smSFX technique can have on other compound classes. To expand smSFX capabilities to the larger global community, we have developed the world’s only mail-in program for XFEL chemical crystallography at the Linac Coherent Light Source, performing data collection as a service for outside sample submitters from the US and worldwide. The inaugural mail-in smSFX experiments identified four highly technologically relevant compound classes where smSFX will have the greatest impact. Metal-organic frameworks (MOFs), covalent-organic frameworks (COFs), inorganic covalent solids, and organic molecular crystals. Our automated sampled delivery and data collection methods allow us to collect data in a high-throughput manner and provide these user groups with high-quality, accurate structures. In one mail-in beamtime, we can impact research efforts on a global scale and contribute new science to multiple technologically relevant compound classes.

X. Shao, X. Shao, M. Wang et al.

<p>New particle formation (NPF) involving organic compounds has been identified as an important process affecting aerosol particle number concentrations in the global atmosphere. Laboratory studies have shown that highly oxygenated organic molecules (HOMs) can make a substantial contribution to NPF, but there is a lack of global model studies of NPF with detailed HOM chemistry. Here, we incorporate a state-of-the-art biogenic HOM chemistry scheme with 96 chemical reactions to a global chemistry–climate model and quantify the contribution to global aerosols through HOM-driven NPF. The updated model captures the frequency of NPF events observed at continental surface sites (normalized mean bias changes from <span class="inline-formula">−</span>96 % to <span class="inline-formula">−</span>15 %) and shows reasonable agreement with measured rates of NPF and sub-20 <span class="inline-formula">nm</span> particle growth. Sensitivity simulations show that compared to turning off the organic nucleation rate, turning off organic initial growth results in a more substantial decrease in aerosol number concentrations. Globally, organics contribute around 45 % of the annual mean vertically integrated nucleation rate (at 1.7 <span class="inline-formula">nm</span>) and 25 % of the vertically averaged growth rate. The inclusion of HOM-related processes leads to a 39 % increase in the global annual mean aerosol number burden and a 33 % increase in cloud condensation nuclei (CCN) burden at 0.5 % supersaturation compared to a simulation with only inorganic nucleation. Our work predicts a greater contribution of organic nucleation to NPF than previous<span id="page11366"/> studies due to the semi-explicit HOM mechanism and an updated inorganic NPF scheme. The large contribution of biogenic HOMs to NPF on a global scale could make aerosol sensitive to changes in biogenic emissions.</p>

Yufan Xie, Yuan Zhong, Jun Wu et al.

Under the increasing severity of drought issues and the urgent need for the resourceful utilization of agricultural waste, this study aimed to compare the soil water retention properties of hydrogels prepared from Chinese cabbage waste (CW) and banana peel (BP) using grafting techniques with acrylic acid (AA) and acrylamide (AAm). Free radical polymerization was initiated with ammonium persulfate (APS), and N, N′-methylene bisacrylamide (MBA) served as the crosslinking agent to fabricate the grafted polymer hydrogels. The hydrogels were subjected to detailed evaluations of their water absorption, reusability, and water retention capabilities through indoor experiments. The optimal hydrogel was identified and its applicability in wheat seedling growth was assessed. The findings revealed that the CW-gel, with an equilibrium swelling ratio of 551.8 g/g in ultrapure water, demonstrated remarkable performance and sustained a high water retention of 57.6% even after drying, which was markedly superior to that of the BP-gel. The CW-gel with the best comprehensive properties significantly improved water retention in sandy soil by 78.2% and prolonged the retention time by five days, indicating its potential for long-term irrigation management. In contrast, the BP-gel showed better performance in clay soil, with an increased water-holding capacity of 43.3%. The application of a 1.5% CW-gel concentration under drought stress significantly improved wheat seedling growth, highlighting the role of hydrogels in agriculture and providing a new path for sustainable water resource management in dryland farming.

J. H. den Otter, D. Pröfrock, T. H. Bünning et al.

After World War II, large amounts of ammunition were dumped in surface waters worldwide, potentially releasing harmful and toxic compounds to the environment. To study their degradation, ammunition items dumped in the Eastern Scheldt in The Netherlands were surfaced. Severe damage due to corrosion and leak paths through the casings were observed, making the explosives in the ammunition accessible to sea water. Using novel techniques, the concentrations of ammunition-related compounds in the surrounding seabed and in the seawater were analyzed at 15 different locations. In the direct vicinity of ammunition, elevated concentrations of ammunition-related compounds (both metals and organic substances) were found. Concentrations of energetic compounds ranged from below the limit of detection (LoD) up to the low two-digit ng/L range in water samples, and from below the LoD up to the one-digit ng/g dry weight range in sediment samples. Concentrations of metals were found up to the low microgram/L range in water and up the low ng/g dry weight in sediment. However, even though the water and sediment samples were collected as close to the ammunition items as possible, the concentrations of these compounds were low and, as far as available, no quality standards or limits were exceeded. The presence of fouling, the low solubility of the energetic compounds, and dilution by the high local water current were concluded to be the main causes for the absence of high concentrations of ammunition-related compounds. As a conclusion, these new analytical methods should be applied to continuously monitor the Eastern Scheldt munitions dump site.

Anja Rehse, Michael Linseis, Mykhailo Azarkh et al.

Valence tautomerism (VT) may occur if a molecule contains two chemically different redox-active units, which differ only slightly in their intrinsic redox potential. Herein, we present three new half-sandwich complexes [(<i>η</i>⁶-arene)Cr(CO)₂L]⁺ with a triarylmethylium substituent appended to the π-coordinated arene and different coligands L (L = CO, P(OPh)₃, PPh₃, <b>1⁺</b>–<b>3⁺</b>) at the chromium atom. Ligand substitution purposefully lowers the half-wave potential for chromium oxidation and thereby the redox potential difference towards tritylium reduction. For the PPh₃-substituted complex <b>3⁺</b>, cyclic voltammetry measurements indicate that chromium oxidation and tritylium reduction occur at (almost) the same potential. This renders the diamagnetic Cr(0)-C₆H₄-CAr₂⁺ form <b>3⁺</b>, and its paramagnetic diradical Cr(I)^+•-C₆H₄-CAr₂^• valence tautomer <b>3^+••</b> energetically nearly degenerate. Temperature-dependent IR spectroscopy indeed shows two pairs of carbonyl bands that are assignable to a Cr(0) and a Cr(I) species, coexisting in a <i>T</i>-dependent equilibrium with almost equal quantities for both at −70 °C. The diradical form with one unpaired spin at the trityl unit engages in a monomer ⇌ dimer equilibrium, which was investigated by means of quantitative EPR spectroscopy. The diradical species <b>1^+••</b>–<b>3^+••</b> were found to be highly reactive, leading to several identified reaction products, which presumably result from hydrogen atom abstraction via the trityl C atom, e.g., from the solvent.

Hossein Omidian, Sumana Dey Chowdhury

Injectable hydrogels have gained popularity for their controlled release, targeted delivery, and enhanced mechanical properties. They hold promise in cardiac regeneration, joint diseases, postoperative analgesia, and ocular disorder treatment. Hydrogels enriched with nano-hydroxyapatite show potential in bone regeneration, addressing challenges of bone defects, osteoporosis, and tumor-associated regeneration. In wound management and cancer therapy, they enable controlled release, accelerated wound closure, and targeted drug delivery. Injectable hydrogels also find applications in ischemic brain injury, tissue regeneration, cardiovascular diseases, and personalized cancer immunotherapy. This manuscript highlights the versatility and potential of injectable hydrogel nanocomposites in biomedical research. Moreover, it includes a perspective section that explores future prospects, emphasizes interdisciplinary collaboration, and underscores the promising future potential of injectable hydrogel nanocomposites in biomedical research and applications.

Huiling Zhou, Dongsheng Tang, Yingjie Yu et al.

Abstract Tumor metastases are considered the leading cause of cancer-associated deaths. While clinically applied drugs have demonstrated to efficiently remove the primary tumor, metastases remain poorly accessible. To overcome this limitation, herein, the development of a theranostic nanomaterial by incorporating a chromophore for imaging and a photosensitizer for treatment of metastatic tumor sites is presented. The mechanism of action reveals that the nanoparticles are able to intervene by local generation of cellular damage through photodynamic therapy as well as by systemic induction of an immune response by immunotherapy upon inhibition of the mTOR signaling pathway which is of crucial importance for tumor onset, progression and metastatic spreading. The nanomaterial is able to strongly reduce the volume of the primary tumor as well as eradicates tumor metastases in a metastatic breast cancer and a multi-drug resistant patient-derived hepatocellular carcinoma models in female mice.

T. Devasena, B. Iffath, R. Renjith Kumar et al.

The manufacturing rate of nanoparticles (10–100 nm) is steadily increasing due to their extensive applications in the fabrication of nanoproducts related to pharmaceuticals, cosmetics, medical devices, paints and pigments, energy storage etc. An increase in research related to nanotechnology is also a cause for the production and disposal of nanomaterials at the lab scale. As a result, contamination of environmental matrices with nanoparticles becomes inevitable, and the understanding of the risk of nanoecotoxicology is getting larger attention. In this context, focusing on the environmental hazards is essential. Hence, this manuscript aims to review the toxic effects of nanoparticles on soil, water, aquatic, and terrestrial organisms. The effects of toxicity on vertebrates, invertebrates, and plants and the source of exposure, environmental and biological dynamics, and the adverse effects of some nanoparticles are discussed.

Regina Vildanova, Alexander Lobov, Leonid Spirikhin et al.

The development of biodegradable polysaccharide hydrogel matrices for cytostatic delivery can improve the therapeutic results of patients by prolonging the action of the drug, reducing its toxicity and providing additional biological activity by polysaccharides. In this work, N-succinyl chitosan/hyaluronic acid dialdehyde/cytostatic formulations have been prepared using two different chitosan grades (30 kDa and 150 kDa) and hyaluronic acid dialdehyde. The interaction of amino groups of N-succinyl chitosan and aldehydes of hyaluronic acid resulted in the formation of azomethine bonds and was demonstrated using ¹³C NMR. The elastic properties of the obtained hydrogels determine their use as implants. Two cytostatics—5-fluorouracil and mitomycin C were chosen as drugs because of their using both in oncology and in ophthalmology for the surgical treatment of glaucoma. Hydrogel formulations containing cytostatic were prepared and drug release was studied using in vitro dialysis method. It was established that the molecular weight of N-succinyl chitosan and rheological properties of hydrogel influenced the drug release behavior of the gelling delivery system. Formulations prepared from N-succinyl chitosan with greatest molecular weight and mitomycin C were found to be the most promising for medical application due to their rheological properties and prolonged drug release. Mild preparation conditions, simplicity of the technique, short gelation time (within a minute), 100% yield of hydrogel, suitability for drug release applications are the main advantages of the obtained hydrogels.