Current advances concerning the most cited metal ions doped bioceramics and silicate-based bioactive glasses for bone tissue engineering

Studies related to biomaterials that stimulate the repair of living tissue have increased considerably, improving the quality of many people's lives that require surgery due to traumatic accidents, bone diseases, bone defects, and reconstructions. Among these biomaterials, bioceramics and bioactive glasses (BGs) have proved to be suitable for coating materials, cement, scaffolds, and nanoparticles, once they present good biocompatibility and degradability, able to generate osteoconduction on the surrounding tissue. However, the role of biomaterials in hard tissue engineering is not restricted to a structural replacement or for guiding tissue regeneration. Nowadays, it is expected that biomaterials develop a multifunctional role when implanted, orchestrating the process of tissue regeneration and providing to the body the capacity to heal itself. In this way, the incorporation of specific metal ions in bioceramics and BGs structure, including magnesium, silver, strontium, lithium, copper, iron, zinc, cobalt, and manganese are currently receiving enhanced interest as biomaterials for biomedical applications. When an ion is incorporated into the bioceramic structure, a new category of material is created, which has several unique properties that overcome the disadvantages of primitive material and favors its use in different biomedical applications. The doping can enhance handling properties, angiogenic and osteogenic performance, and antimicrobial activity. Therefore, this review aims to summarize the effect of selected metal ion dopants into bioceramics and silicate-based BGs in bone tissue engineering. Furthermore, new applications for doped bioceramics and BGs are highlighted, including cancer treatment and drug delivery.     

Piperacillin/tazobactam‐induced neurotoxicity in a hemodialysis patient: A case report

Antibiotics are potentially a cause of neurotoxicity in dialysis patients, the most common are the beta‐lactams as ceftazidime and cefepime, and few cases have been reported after piperacillin/tazobactam use. This report presents a case of a hypertensive and diabetic 67‐year‐old woman in regular hemodialysis, which previously had a stroke. She was hospitalized presenting pneumonia, which was initially treated with cefepime. Two days after treatment, she presented dysarthria, left hemiparesis, ataxia, and IX and X cranial nerves paresis. Computed tomography showed no acute lesions and cefepime neurotoxicity was hypothesized, and the antibiotic was replaced by piperacillin/tazobactam. The neurologic signs disappeared; however, 4 days after with piperacillin/tazobactam treatment, the neurological manifestations returned. A new computed tomography showed no new lesions, and the second antibiotic regimen withdrawn. After two hemodialysis sessions, the patient completely recovered from neurological manifestations. The patient presented sequentially neurotoxicity caused by two beta‐lactams antibiotics. This report meant to alert clinicians that these antibiotics have dangerous neurological effects in chronic kidney disease patients.     

Inhibition of acid rock drainage from uranium ore waste using a conventional neutralization and precipitation treatment

Glass columns (length 50 cm, i.d. 4 cm) containing 900 g of uranium ore waste were subjected to a three-step process: (1) acid drainage generation, (2) neutralization and precipitation treatment and, again, (3) acid drainage generation. In the first acid generation step, lasting about one year, different variables (pyrite addition, inoculation and irrigation solution) were tested by measuring effluent pH, redox potential, total iron and sulphate. Conditions of acid generation were satisfactorily reproduced, reaching stable pH values around 2.0 that were determined mainly by pyrite addition and the type of irrigation solution used (distilled water or ferrous sulphate). The neutralization and precipitation treatment consisted of alternating irrigations of a neutralizing solution (CaO saturated plus NaOH) and a precipitating solution (ferric sulphate saturated). This treatment caused accumulation of basic iron sulphate and iron oxide precipitates according to SEM studies. After this treatment, the barrier effect created by the reaction products was checked, using irrigation solutions similar to the first step. The effluents collected showed higher pH and lower redox potential, total iron and sulphate values than those observed before the treatment, evidencing inhibition of acid drainage generation.     

Direct synthesis of copper faujasite

Copper containing faujasite has been successfully prepared for the first time using a direct synthesis method. Faujasite type zeolite can be prepared in the presence of copper species by tuning the synthesis conditions. Ammonium hydroxide was used to form a copper complex that was later mixed with the reacting gel. Sodium is required to obtain copper faujasite. The complete elimination of sodium ions from the starting gel produces amorphous material. Crystallization took place at 358 K for 11 days. Crystallization temperature of 373 K produces ANA type zeolite as an impurity. Increasing by two times the amount of copper complex added to the reacting gel increases the crystallization time of Cu-FAU from 11 to 20 days (the crystallization rate decreases). The copper containing faujasite obtained was characterized by XRD, FESEM, EDX, EPR, FT-IR, TPR, and BET. According to the XRD pattern only FAU type zeolite was obtained. According to TPR experiments, the reduction temperature for Cu²⁺ ions present in Cu-FAU prepared by direct synthesis was 70 K more than for Cu-FAU prepared by ion-exchange. This difference can be due to the different location of the copper ions in the supercages or in the sodalite cages of the faujasite.     

Trends in Hydrological Parameters of a Southern Brazilian Watershed and its Relation to Human Induced Changes

The Piracicaba river basin is a subtropical watershed located in the southeastern region of Brazil. With an area of 12 400 km², the basin is a typical example of new landscape resulting from development in tropical and sub-tropical regions: establishment of intensive industrial and agricultural processes were followed by significant population growth and water management. This scenario has led to significant increase in water demand and decrease in water quality. The main objective of this study is the detection of changes in the patterns of flow and precipitation in the basin, and its possible relation to man-induced changes. Statistical analyses were performed on records of precipitation, evapotranspiration and streamflow, from 1947 to 1991. Precipitation and evapotranspiration totals showed significant increasing trends for the entire basin. From eight streamflow gauge stations, half showed significant decreasing trend. The most probable cause of such trends is the export of water from the basin to the metropolitan region of São Paulo city.     

Microstructural Modelling of Nb Microalloyed Steels during Thin Slab Direct Rolling Processing

The microstructural evolution during the hot rolling of coarse grain sized austenite has been modeled considering all the microstructural mechanisms (dynamic, static and metadynamic recrystallization, strain induced precipitation) that can take place during an industrial TSDR production of three Nb microalloyed steels. Based on the results obtained from the model, processing maps have been drawn for 0.02%, 0.035% and 0.05% Nb microalloyed steels. Optimum processing conditions to exploit all the benefits of the Nb microalloying have been defined considering a final gauge thickness range between 1.5 and 12.65 mm. In addition, and facing the difficulties present in the production of thick hot strip, several alternative thermomechanical schedules are proposed, which would originate microstructures with a suitable combination of homogeneity and retained strain prior to transformation.     

A Tale of Two Dams: The Impact of Reservoir Management on Rural Depopulation in Central Spain

In rural areas, depopulation is mainly due to a lack of economic and employment opportunities. In this context, the reservoirs already built can be a source of socioeconomic development based on tourism and outdoor leisure activities. The condition for this development to materialize is that reservoir management considers these activities. In Central Spain, a process of rural depopulation has been generated in the municipalities around the reservoirs at the Upper Tagus River, as water management allows water transfers from the Tagus to the Segura River without taking into account regulations that prioritize and protect donor basin users. Through the comparison of reservoir water management and demographic data of two rural areas close to the reservoirs, this article reveals the direct relationship between reservoir management that enables recreational uses with its consequent socioeconomic development and the maintenance of the population in the territory. Consequently, reservoir water management based on the socioeconomic development of reservoir banks is necessary and a priority over transfers to another basin.

     

Link between Lipid Second Messengers and Osmotic Stress in Plants

Plants are subject to different types of stress, which consequently affect their growth and development. They have developed mechanisms for recognizing and processing an extracellular signal. Second messengers are transient molecules that modulate the physiological responses in plant cells under stress conditions. In this sense, it has been shown in various plant models that membrane lipids are substrates for the generation of second lipid messengers such as phosphoinositide, phosphatidic acid, sphingolipids, and lysophospholipids. In recent years, research on lipid second messengers has been moving toward using genetic and molecular approaches to reveal the molecular setting in which these molecules act in response to osmotic stress. In this sense, these studies have established that second messengers can transiently recruit target proteins to the membrane and, therefore, affect protein conformation, activity, and gene expression. This review summarizes recent advances in responses related to the link between lipid second messengers and osmotic stress in plant cells.     

Stereoselective Synthesis and Antiallodynic Activity of 3-Hydroxylated Paroxetines

The design, stereoselective synthesis and in vivo antiallodynic activity of four novel paroxetine analogs, named 3-hydroxy paroxetines (3HPXs), is reported herein. Among the novel synthesized compounds, three showed an antiallodynic effect, while (R,R)-3HPX was found to be 2.5 times more bioactive than (-)-paroxetine itself in neuropathic rats. Consequently, the current investigation not only discloses a novel promising analgesic drug, but also reveals that functionalization at the C3 position of paroxetine could be as effective as the common functionalization at either C4 or within the sesamol group.