Revista de Ciências Químicas

The isomorphism of S-bearing feldspathoids belonging to the cancrinite, sodalite, tugtupite, vladimirivanovite, bystrite, marinellite and scapolite structure types has been investigated using a multimethodical approach based on infrared, Raman and electron spin resonance (ESR), as well as ultraviolet, visible and near infrared (UV-Vis-near IR) absorption spectroscopy methods and involving chemical and X-ray diffraction data. Sapozhnikovite Na₈(Al₆Si₆O₂₄)(HS)₂ and sulfite and thiosulfate analogues of cancrinite are synthesized hydrothermally and characterized by means of electron microprobe analyses, powder X-ray diffraction and Raman spectroscopy. The possibility of the incorporation of significant amounts of SO₄²⁻, S₄ and SO₃²⁻ in the crystal structures of cancrisilite, sulfhydrylbystrite and marinellite, respectively, has been established for the first time. Thermal conversions of S-bearing groups in the synthetic sulfite cancrinite and sapozhnikovite analogues as well as natural vladinirivanovite and S₄^- bearing haüyne under oxidizing and reducing conditions have been studied using the multimethodical approach. The SO₄²⁻ and S²⁻ anions and the S₃^•- radical anion are the most stable S-bearing species under high-temperature conditions (in the range of 700-800°C); their ratio in the heated samples is determined by the redox conditions and charge-balance requirement. The HS⁻ and S₅²⁻ anions are stable only under highly reducing conditions.

The time of a woman's life during pregnancy during which the circulatory system experiences hemodynamic and biochemical changes is known as pregnancy. There is a higher risk of developing chronic venous disease (CVD) at this time due to the remodelling of blood arteries and the exchange of maternal-fetal products. CVD may have long-term effects on both the mother and the baby after delivery. Previously, we looked into how pregnancy-associated CVD differs from healthy controls (HC) who have no history of the disease in terms of placental architecture at angiogenesis, lymphangiogenesis and villi morphology. Through the use of multiple markers, we wanted to more thoroughly explore the oxidative stress response in the placenta from women with CVD versus HC. A prospective, analytical and observational cohort study including 114 pregnant women was carried out (32 weeks). 62 patients in all had a clinical diagnosis of CVD. 52 healthy controls (HC) who had no prior history of CVD were also investigated. Real-time polymerase chain reaction and immunohistochemistry were used to examine the gene and protein expressions of NRF2, KEAP1, CUL3 and GSK-3. While Keap1, CUL-3 and GSK-3 gene and protein expressions were significantly reduced in the placental villi of women with CVD, Nrf2 gene and protein expressions were significantly higher. In the placenta of women with CVD, our findings identified abnormal gene and protein expression of Nrf2 and some of its primary regulators, Keap1, CUL-3 and GSK-3, which may be a sign of the oxidative environment seen in this tissue.

Since the self-assembled monolayer (SAM) is the most typical organic assembly used to create alkane-thiolates monolayers on gold electrodes, the modified SAM on gold has a wide variety of applications in many different study fields. In order to determine the most effective method of SAM removal so the ICE can be reused, this work investigated the desorption of a SAM that was formed on the gold surface of an interdigitated chainshaped electrode (the ICE, a novel electrode design, was created by our lab). Using a sodium borohydride solution and a short-term treatment, a straightforward and effective solution-based cleaning approach was used to remove a SAM from the gold surface of the ICE. This procedure was successful in recovering 90.3% of the ICE's original electrochemical properties. The successful re-deposition of a SAM onto the electrode surface following the removal process demonstrated that the ICE could be used again, yielding a high efficiency percentage of 90.1% for the reusability of ICE with the SAM modification. When removing SAM and recycling electrodes, the electrode interface alterations were examined using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The bonding structure and chemical state of the unmodified ICE and the changed ICE at each treatment step were characterised using the potent spectral techniques of X-ray photoelectron and Fouriertransform infrared spectroscopy. We confirmed and demonstrated the efficacy of this promising method for the removal of a SAM from the ICE and the re-use of ICE in the field of material deposition, with the goals of cost savings, improved experimental handling and environmental protection, based on the thorough discussion of analytical chemistry from the obtained EIS and CV data in this study.

In this article, we discuss the creation of a photonic biosensor device as an additional diagnostic tool for cancer treatment monitoring. To get around detection reliability, sensitivity, specificity, compactness and cost concerns, the suggested device incorporates multidisciplinary principles from the reader/packaging, nano-biochemical, micro-fluidic and photonic platforms. The sensing is done by measuring the phase shift of the output signal, produced by the binding of the analyte on the functionalized aMZI surface and the photonic sensor is based on an array of six asymmetric Mach Zender Interferometer (aMZI) waveguides on silicon nitride substrates. The waveguides' morphological design results in an improved sensitivity (5000 nm/RIU) in compared to earlier technologies. By combining this platform with a cutting-edge biofunctionalization technique that uses material-selective surface chemistries and high-resolution laser printing of biomaterials, an integrated photonics biosensor device that makes use of disposable microfluidics cartridges is created. Blood serum samples from cancer patients are used to test the device. The device is used to identify two circulating biomarkers, periostin (POSTN) and transforming growth factor beta-induced protein (TGFBI), which are overexpressed by cancer stem cells.

In this article, we describe the creation and characterisation of self-assembling nucleopeptides containing guanosine that can form nanosheets and nanofibers. We suggest that the nucleopeptide's peptide component drives the assembly into -sheet structures, with hydrogen-bonded guanosine generating additional secondary structures cooperatively inside the peptide framework. This is based on spectroscopic and microscopy studies. It's interesting to note that the C-terminal peptide chemistry, rather than the metal cation responsiveness common to guanine-based materials, is what drives the different supramolecular morphologies. This research will aid in the advancement of the design of applications for these supramolecular guanosine-containing nucleopeptides and demonstrates the structural diversity of self-assembling nucleopeptides.