prolonged exposure
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2022 ◽  
Author(s):  
José Iván Morales Arredondo ◽  
Armienta Hernández ◽  
I.Z. Flores-Ocampo ◽  
R. Flores-Vargas

Abstract Chronic exposure from drinking water with naturally high concentrations of fluoride (F⁻) has serious health consequences in several regions across the world including north-central Mexico as Guanajuato State, where the rural population is particularly dependent on untreated groundwater pumped from wells that have natural F- concentrations higher than those allowed by national and international regulations. The contaminated aquifers in the area are usually located in fractured volcanic environment that interacts with sedimentary basins and have a carbonate basement. Few studies focused on identifying the origin and hydrogeochemical processes related to fluoride release and mobilization have been developed, and even fewer that quantify the natural content of F in the geological environment. In this study, an evaluation of fluoride in volcanic rocks collected from 11 sampling sites along the Sierra de Codornices (Guanajuato State, Central Mexico) was carried out. The fluoride content is disseminated in volcanic rocks and the highest contents were obtained in felsic rocks. According to results obtained of a sampling campaign of 32 wells in 2019 their statistical and hydrogeochemical evaluation suggest that F- mobilization in groundwater from Juventino Rosas and Villagran municipalities, is a product of volcanic glass dissolution, a process involved in alkaline desorption occurring on the surfaces of F-containing minerals, and possibly on ion exchange occurring in minerals and some clays or even in deep fluids enriched in F. All these processes may be accelerated by the geothermal characteristics of the groundwater in the study area. The hydrogeochemical results and the epidemiological survey conducted indicate that children and older adults of Praderas de la Venta are at risk of exposure to F- due to the high concentrations ingested over a long period of time, to the toxicity of the element and its ability to accumulate in the bones. Prolonged exposure to high concentrations increases the risk.


Author(s):  
Shannon Hunter ◽  
Rebecca McDougal ◽  
Nari Williams ◽  
Peter Scott

AbstractPhosphite is used to control and manage many phytophthora diseases in horticultural systems worldwide and natural ecosystems in Australia, Africa, New Zealand and parts of Northern America and Europe. Phosphite does not kill Phytophthora species, but inhibits growth while also stimulating host defence responses. Phytophthora species differ in their underlying tolerance to phosphite and isolates have been shown to acquire tolerance after prolonged exposure. Intra- and inter-specific variability in phosphite sensitivity is of interest to determine the efficacy and sustainability of phosphite for the treatment of phytophthora diseases, which continue to spread globally. Seven Phytophthora species were tested for their sensitivity to phosphite in vitro in a mycelial growth experiment. Phytophthora agathidicida was the species most sensitive to phosphite, being inhibited by 98.7% on average at the lowest phosphite treatment (15 µg/mL phosphite), followed by P. aleatoria, P. cinnamomi, P. pluvialis, P. multivora, P. kernoviae and P. citricola. Huge intraspecific variability was observed with P. kernoviae, which raises the question of whether diseases caused by P. kernoviae such as phytophthora needle blight of Pinus radiata could be managed effectively with phosphite. Further work is required to determine the phosphite sensitivity of different introduced and native Phytophthora species growing in key hosts and whether tolerance observed in vitro is also expressed in vivo.


2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Sophia Åkerblom ◽  
Sean Perrin ◽  
Marcelo Rivano Fischer ◽  
Lance M. McCracken

Abstract Objectives It is unclear how to address PTSD in the context of chronic pain management. Here we examine the potential benefits of an addition of prolonged exposure (PE) therapy for PTSD for adults attending multidisciplinary CBT for chronic pain. Methods Four adults seeking treatment for chronic pain from a specialized pain rehabilitation service were offered PE for PTSD using a replicated, randomized, single-case experimental phase design, prior to commencing a 5-week multidisciplinary CBT program for chronic pain. Pre-, post-, follow-up, and daily measures allowed examination of PTSD and pain outcomes, potential mediators, and the trajectory of these outcomes and potential mediators during the subsequent pain-focused CBT program. Results Visual inspection of the daily data demonstrated changes in all outcome variables and potential mediators during the PE phase. Changes came at different times and at different rates for the four participants, highlighting the individual nature of putative change mechanisms. Consistent with expectation, PE produced reliable change in the severity of PTSD symptoms and trauma-related beliefs for all four participants, either by the end of the PE phase or the PE follow-up, with these gains maintained by the end of the 5-week pain-focused CBT program. However, few reductions in pain intensity or pain interference were seen either during the PE phase or after. Conclusions Although “disorder specific” approaches have dominated the conceptualising, study, and treatment of conditions like PTSD and chronic pain, such approaches may not be optimal. It may be better instead to approach cases in an individual and process-focused fashion. Ethical committee number 2013/381.


Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 365
Author(s):  
Anna Švančárková ◽  
Dagmar Galusková ◽  
Aleksandra Ewa Nowicka ◽  
Helena Pálková ◽  
Dušan Galusek

The influence of 4% acetic acid (pH~2.4) and an alkaline solution of NaOH (pH~10) on the corrosion resistance and micromechanical properties of disilicate crystals containing glass-ceramics (LS2-GC’s) is studied. Partially crystallized lithium metasilicate crystal containing glass-ceramics (LS-GC’s) are annealed to fully LS2-GC’s using a one stage and a two-stage heating to induce nucleation. Materials with various chemical and wear resistance are prepared. The content of the crystalline phase in the material annealed in the two-stage process A is 60.0% and increases to 72.2% for the material heated in the one-stage process B. The main elements leached in the acidic medium are lithium and phosphorus, while lithium, silicon, and phosphorus leached into the alkaline environment. Material B exhibits better chemical resistance to the corrosive influence of 4% acetic acid under quasi-dynamic conditions. In the alkaline corrosion medium, silicon is leached from material A faster compared to the material B. After prolonged exposure to acidic or basic environments, both materials show evidence of surface structural changes. A decrease of the sliding wear resistance is observed after corrosion in the acidic environment under dynamic conditions. In both materials, the wear rate increases after corrosion.


Author(s):  
Zheng-Hong Li ◽  
Rong Xu ◽  
Jun Shi ◽  
Man-Shu Yu ◽  
Yu Zhong ◽  
...  

Peritoneal fibrosis (PF) is a disease caused by prolonged exposure of the peritoneum to high levels of dialysis fluid. Astragalus total saponins (ATS) is a phytochemical naturally occurring in Radix Astragali that has anti-inflammatory and anti-oxidant properties. In this study, we constructed an in vivo model of PF using 4.25% glucose-containing administered intraperitoneally to rats and incubated peritoneal mesothelial cells (PMCs) with 4.25% glucose-containing peritoneal dialysis fluid to construct an in vitro model of PF. Furthermore, siRNA of PGC-1[Formula: see text] was used to inhibit the expression of PGC-1[Formula: see text] to further investigate the mechanism of the protective effect of ATS on PF. In both in vivo and in vitro models, ATS treatment showed a protective effect against PF, with ATS reducing the thickness of peritoneal tissues in PF rats, increasing the viability of PMCs, increasing the mitochondrial membrane potential and reducing apoptosis ratio. ATS treatment also reduced the expressions of peritoneal fibrosis markers (Smad2, p-Smad2 and [Formula: see text]-SMA) and apoptosis markers (Caspase3, cleaved-Caspase3 and Bax) and restored the expressions of mitochondrial synthesis proteins (PGC-1[Formula: see text], NRF1 and TFAM) in ATS-treated peritoneal tissues or PMCs. Furthermore, in the presence of PGC-1[Formula: see text] inhibition, the protective effect of ATS on PF was blocked. In conclusion, ATS treatment may be an effective therapeutic agent to inhibit high glucose-induced in peritoneal fibrosis through PGC-1[Formula: see text]-mediated apoptosis.


Pathogens ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 53
Author(s):  
Angela Brunetti ◽  
Antonio Matere ◽  
Valentina Lumia ◽  
Vittorio Pasciuta ◽  
Valeria Fusco ◽  
...  

Olive trees are infected and damaged by Botryosphaeriaceae fungi in various countries. The botryosphaeriaceous fungus Neofusicoccum mediterraneum is highly aggressive and is a major concern for olive groves in Spain and California (USA), where it causes ‘branch and twig dieback’ characterized by wood discoloration, bark canker, and canopy blight. During surveys of olive groves in Apulia (southern Italy), we noticed that—in some areas—trees were heavily affected by severe branch and twig dieback. In addition, chlorosis and the appearance of red-bronze patches on the leaf preceded the wilting of the foliage, with necrotic leaves persisting on the twigs. Given the severity of the manifestation in zones also subject to olive quick decline syndrome (OQDS) caused by Xylella fastidiosa subsp. pauca, we investigated the etiology and provide indications for differentiating the symptoms from OQDS. Isolation from diseased wood samples revealed a mycete, which was morphologically and molecularly identified as N. mediterraneum. The pathogenicity tests clearly showed that this fungus is able to cause the natural symptoms. Therefore, also considering the low number of tested samples, N. mediterraneum is a potential causal agent of the observed disease. Specifically, inoculation of the twigs caused complete wilting in two to three weeks, while inoculation at the base of the stem caused severe girdling wedge-shaped cankers. The growth rate of the fungus in in vitro tests was progressively higher from 10 to 30 °C, failing to grow at higher temperatures, but keeping its viability even after prolonged exposure at 50 °C. The capacity of the isolate to produce catenulate chlamydospores, which is novel for the species, highlights the possibility of a new morphological strain within N. mediterraneum. Further investigations are ongoing to verify whether additional fungal species are involved in this symptomatology.


2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Jiani Huang ◽  
Wangshu Yu ◽  
Qin He ◽  
Xiaoying He ◽  
Ming Yang ◽  
...  

AbstractAge-related cell loss underpins many senescence-associated diseases. Apoptosis of lens epithelial cells (LECs) is the important cellular basis of senile cataract resulted from prolonged exposure to oxidative stress, although the specific mechanisms remain elusive. Our data indicated the concomitance of high autophagy activity, low SQSTM1/p62 protein level and apoptosis in the same LEC from senile cataract patients. Meanwhile, in primary cultured LECs model, more durable autophagy activation and more obvious p62 degradation under oxidative stress were observed in LECs from elder healthy donors, compared with that from young healthy donors. Using autophagy-deficiency HLE-B3 cell line, autophagy adaptor p62 was identified as the critical scaffold protein sustaining the pro-survival signaling PKCι-IKK-NF-κB cascades, which antagonized the pro-apoptotic signaling. Moreover, the pharmacological inhibitor of autophagy, 3-MA, significantly inhibited p62 degradation and rescued oxidative stress-induced apoptosis in elder LECs. Collectively, this study demonstrated that durable activation of autophagy promoted age-related cell death in LECs. Our work contributes to better understanding the pathogenesis of senescence-associated diseases.


2022 ◽  
pp. 1454-1476
Author(s):  
Shubhangini Rathore

Contemporary industries face new competition requiring employees to work for longer hours under competitive time-bound deadlines. Prolonged exposure to such stressful situations leads to a depletion and exhaustion of resources in the mind and body with dysfunctional effects on job performance and overall organizational effectiveness. The Indian IT industry is a fast-paced service industry that is characterized by such stressful work situations and related outcomes. This chapter analyses the various factors that contribute to organizational stress and the role of demographic factors on role stress among the professionals of the Indian IT industry. A sample of 250 employees has been collected from the Delhi NCR region. Role stress has been measured by using the ORS scale which comprises of 10 dimensions of the role of stress that are measured by 50 items. The results show that there is a considerable amount of work related stress along with a significant impact of demographic factors on the role of stress amongst the IT professionals.


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