Impact of Cr Doping on the Structural, Optical, and Magnetic Properties of Sol-Gel-Synthesized Bi0.80Ba0.10Pr0.10FeO3 Nanopowders.

The sol-gel route was used to synthesize a series of compounds of the system Bi0.8Ba0.10Pr0.10Fe1-x Cr x O3 within the 0 ≤ x ≤ 0.15 compositional range. To explore the impact of Cr3+ ion substitution on the structural, dielectric, optical, and magnetic properties, we introduced varying concentrations of Cr3+ while maintaining a fixed 10% atomic concentration of each Ba2+ and Pr2+ in BiFeO3. X-ray diffraction analysis revealed a structural phase transition from rhombohedral (R3c) for an undoped (i.e., without Cr) sample to two coexisting phases, i.e., a mix of rhombohedral and orthorhombic (Pbnm) phases for the Cr-doped samples. Cr3+ doping significantly changes the band gap energy from 1.84 eV (x = 0.0) to 1.93 eV (x = 0.15), which makes this material suitable for photovoltaic applications. Furthermore, each sample exhibited ferromagnetic behavior due to the disruption of the spiral spin structures and adjustments in superexchange interactions, attributed to modifications in the Fe-O and Fe-O-Fe bond lengths. A reduction in magnetization is observed at higher Cr concentrations that can be ascribed to the dilution of magnetic moments due to the increase of the orthorhombic phase percentage and the introduction of nonmagnetic Cr3+ ions. Our results show that Cr doping in the Bi0.8Ba0.10Pr0.10FeO3 system induces enhanced multiferroic properties at room temperature.

Self-reported side effects of COVID-19 vaccines among health professions students in India.

Studies focusing on the safety and common side effects of vaccines play a crucial role in enhancing public acceptance of vaccination. Research is scarce regarding the usage of COVID-19 vaccines and the side effects experienced by health professions students in India and other countries. This study aimed to document self-reported side effects associated with COVID-19 vaccination among medical and dental students of six medical and dental colleges and teaching hospitals in four states (Tamil Nadu, Madhya Pradesh, Gujarat, and West Bengal) of India. A cross-sectional survey using purposive sampling of medical and dental students was conducted from 26 April to 26 May 2021. Data was collected using a Google Forms questionnaire capturing information regarding receiving COVID-19 vaccines, side effects and symptoms, onset and duration of symptoms, use of treatment to alleviate symptoms, awareness of haematologic risks associated with vaccination, and side effects from previous (non-COVID-19) vaccinations. The majority (94.5%) of participants received both doses of the Covishield/AstraZeneca COVID-19 vaccine. Among participants (n = 492), 45.3% (n = 223) reported one or more side effects. The most frequently reported side effects were soreness of the injected arm (80.3%), tiredness (78.5%), fever (71.3%), headache (64.1%), and hypersomnia (58.7%). The two most common severe symptoms were fever (14.8%) and headache (13%). Most side effects appeared on the day of vaccination: soreness of the injection site (57%), fever (43.1%), and tiredness (42.6%). Most reported symptoms persisted for one to three days-soreness of the injection site (53%), fever (47.1%), and headache (42.6%). Logistic regression showed that women were almost 85% less likely to report side effects. The study's findings corroborate the safety of the Covishield/AstraZeneca vaccine's first dose, evidenced by the relatively minor and transient nature of the side effects. However, the study underscores the necessity for ongoing research to assess the long-term impacts of COVID-19 vaccines, especially in the context of booster doses, thereby contributing to the global understanding of vaccine safety and efficacy.

Perioperative outcomes and risk factors for major complications associated with nephrectomy for Xanthogranulomatous pyelonephritis: a multicenter study.

PURPOSE: To determine the risk factors associated with major complications in patients with histologically confirmed Xanthogranulomatous pyelonephritis (XGP) who underwent nephrectomy. METHODS: A multicenter retrospective study was performed including patients who underwent nephrectomy between 2018 and 2022 with histopathological diagnosis of XGP. Clinical and laboratory parameters at the initial presentation were evaluated. Data on extension of XGP was recorded as per the Malek clinical-radiological classification. Characteristics of nephrectomy and perioperative outcomes were obtained. The primary outcome was major complications, defined as a CD ≥ grade 3 and the need for intensive care unit (ICU) admission. Secondary outcomes included the comparison of complications evaluating the nephrectomy approach (transperitoneal, retroperitoneal, and laparoscopic). A sub-analysis stratifying patients who needed ICU admission and Malek classification was performed. RESULTS: A total of 403 patients from 10 centers were included. Major complications were reported in 98 cases (24.3%), and organ injuries were reported in 58 patients (14.4%), being vascular injuries the most frequent (6.2%). Mortality was reported in 5 cases (1.2%). A quick Sepsis-related Organ Failure Assessment (qSOFA) score ≥ 2, increased creatinine, paranephric extension of disease (Malek stage 3), a positive urine culture, and retroperitoneal approach were independent factors associated with major complications. CONCLUSION: Counseling patients on factors associated with higher surgical complications is quintessential when managing this disease. Clinical-radiological staging, such as the Malek classification may predict the risk of major complications in patients with XGP who will undergo nephrectomy. A transperitoneal open approach may be the next best option when laparoscopic approach is not feasible.

Prognosis of Extended-Spectrum-Beta-Lactamase-Producing Agents in Emphysematous Pyelonephritis-Results from a Large, Multicenter Series.

BACKGROUND: Emphysematous pyelonephritis (EPN) is a necrotizing infection of the kidney and surrounding tissues with significant mortality. We aimed to assess the clinical factors and their influence on prognosis in patients being managed for EPN with and without ESBL-producing bacteria and to identify if those with EPN due to ESBL infections fared any different. METHODS: A retrospective analysis was performed on patients with EPN diagnosis from 22 centers across 11 countries (between 2013 and 2020). Demographics, clinical presentation, biochemical parameters, radiological features, microbiological characteristics, and therapeutic management were assessed. Univariable and multivariable analyses were performed to determine the independent variables associated with ESBL pathogens. A comparison of ESBL and non-ESBL mortality was performed evaluating treatment modality. RESULTS: A total of 570 patients were included. Median (IQR) age was 57 (47-65) years. Among urine cultures, the most common isolated pathogen was Escherichia coli (62.2%). ESBL-producing agents were present in 291/556 urine cultures (52.3%). In multivariable analysis, thrombocytopenia (OR 1.616 95% CI 1.081-2.413, p = 0.019), and Huang-Tseng type 4 (OR 1.948 95% CI 1.005-3.778, p= 0.048) were independent predictors of ESBL pathogens. Patients with Huang-Tseng Scale type 1 had 55% less chance of having ESBL-producing pathogens (OR 1.616 95% CI 1.081-2.413, p = 0.019). Early nephrectomy (OR 2.3, p = 0.029) and delayed nephrectomy (OR 2.4, p = 0.015) were associated with increased mortality in patients with ESBL infections. Conservative/minimally invasive management reported an inverse association with mortality (OR 0.314, p = 0.001). CONCLUSIONS: ESBL bacteria in EPN were not significantly associated with mortality in EPN. However, ESBL infections were associated with poor prognosis when patients underwent nephrectomy compared conservative/minimally invasive management.

The Current Situation Regarding Long-Acting Insulin Analogues Including Biosimilars Among African, Asian, European, and South American Countries; Findings and Implications for the Future.

Background: Diabetes mellitus rates continue to rise, which coupled with increasing costs of associated complications has appreciably increased global expenditure in recent years. The risk of complications are enhanced by poor glycaemic control including hypoglycaemia. Long-acting insulin analogues were developed to reduce hypoglycaemia and improve adherence. Their considerably higher costs though have impacted their funding and use. Biosimilars can help reduce medicine costs. However, their introduction has been affected by a number of factors. These include the originator company dropping its price as well as promoting patented higher strength 300 IU/ml insulin glargine. There can also be concerns with different devices between the manufacturers. Objective: To assess current utilisation rates for insulins, especially long-acting insulin analogues, and the rationale for patterns seen, across multiple countries to inform strategies to enhance future utilisation of long-acting insulin analogue biosimilars to benefit all key stakeholders. Our approach: Multiple approaches including assessing the utilisation, expenditure and prices of insulins, including biosimilar insulin glargine, across multiple continents and countries. Results: There was considerable variation in the use of long-acting insulin analogues as a percentage of all insulins prescribed and dispensed across countries and continents. This ranged from limited use of long-acting insulin analogues among African countries compared to routine funding and use across Europe in view of their perceived benefits. Increasing use was also seen among Asian countries including Bangladesh and India for similar reasons. However, concerns with costs and value limited their use across Africa, Brazil and Pakistan. There was though limited use of biosimilar insulin glargine 100 IU/ml compared with other recent biosimilars especially among European countries and Korea. This was principally driven by small price differences in reality between the originator and biosimilars coupled with increasing use of the patented 300 IU/ml formulation. A number of activities were identified to enhance future biosimilar use. These included only reimbursing biosimilar long-acting insulin analogues, introducing prescribing targets and increasing competition among manufacturers including stimulating local production. Conclusions: There are concerns with the availability and use of insulin glargine biosimilars despite lower costs. This can be addressed by multiple activities.

Heterogeneity in the effect of mid-childhood height and weight gain on human capital at age 14-15 years: Evidence from Ethiopia, India, Peru, and Vietnam.

BACKGROUND: Under-nutrition in early childhood has harmful impacts on human capital formation in children, with implications for educational, adult health, and labor market outcomes. We investigate the association of linear growth and weight gain in mid-childhood with years of schooling, the Peabody Picture Vocabulary Test score, and math test score during the adolescent age of 14-15 years. METHODS: Data were derived from the Young Lives study conducted in four low- and middle-income countries (Ethiopia, India, Peru, and Vietnam). The data had detailed information on the children anthropometry and characteristics of the child, household, and community. Multivariate regression analysis, adjusted for the confounding variables, was used to investigate the association between mid-childhood health, measured by conditional linear growth and relative weight gain, and human capital outcomes in adolescent age. RESULTS: After controlling for several confounders, one cm increase in conditional linear growth increased years of schooling by 0.034 years and the Peabody Picture Vocabulary Test score and math test score by 0.474 and 0.083 points respectively. Relative weight gain was negatively associated with years of schooling and math test score. There is no evidence of heterogeneous effects by rural, gender, and household wealth. In the quantile regression analyses, the association between conditional linear growth and outcomes is stronger at the lower level of years of schooling and the Peabody Picture Vocabulary Test score. CONCLUSION: Our study highlights that mid-childhood nutritional intervention targeted for students at the lower level of education distribution can accelerate the rate of human capital accumulation in low- and middle-income countries.

Catalase Expression in Azospirillum brasilense Sp7 Is Regulated by a Network Consisting of OxyR and Two RpoH Paralogs and Including an RpoE1→RpoH5 Regulatory Cascade.

The genome of Azospirillum brasilense encodes five RpoH sigma factors: two OxyR transcription regulators and three catalases. The aim of this study was to understand the role they play during oxidative stress and their regulatory interconnection. Out of the 5 paralogs of RpoH present in A. brasilense, inactivation of only rpoH1 renders A. brasilense heat sensitive. While transcript levels of rpoH1 were elevated by heat stress, those of rpoH3 and rpoH5 were upregulated by H2O2 Catalase activity was upregulated in A. brasilense and its rpoH::km mutants in response to H2O2 except in the case of the rpoH5::km mutant, suggesting a role for RpoH5 in regulating inducible catalase. Transcriptional analysis of the katN, katAI, and katAII genes revealed that the expression of katN and katAII was severely compromised in the rpoH3::km and rpoH5::km mutants, respectively. Regulation of katN and katAII by RpoH3 and RpoH5, respectively, was further confirmed in an Escherichia coli two-plasmid system. Regulation of katAII by OxyR2 was evident by a drastic reduction in growth, KatAII activity, and katAII::lacZ expression in an oxyR2::km mutant. This study reports the involvement of RpoH3 and RpoH5 sigma factors in regulating oxidative stress response in alphaproteobacteria. We also report the regulation of an inducible catalase by a cascade of alternative sigma factors and an OxyR. Out of the three catalases in A. brasilense, those corresponding to katN and katAII are regulated by RpoH3 and RpoH5, respectively. The expression of katAII is regulated by a cascade of RpoE1→RpoH5 and OxyR2.IMPORTANCEIn silico analysis of the A. brasilense genome showed the presence of multiple paralogs of genes involved in oxidative stress response, which included 2 OxyR transcription regulators and 3 catalases. So far, Deinococcus radiodurans and Vibrio cholerae are known to harbor two paralogs of OxyR, and Sinorhizobium meliloti harbors three catalases. We do not yet know how the expression of multiple catalases is regulated in any bacterium. Here we show the role of multiple RpoH sigma factors and OxyR in regulating the expression of multiple catalases in A. brasilense Sp7. Our work gives a glimpse of systems biology of A. brasilense used for responding to oxidative stress.

Effects of health insurance on birth weight in Mexico.

This paper estimates the effect of mother's insurance coverage on neonatal outcomes in Mexico using hospital-based administrative data. Using an instrumental variable approach to identify the causal effects of health insurance on infant health, we find that mother's insurance coverage has positive impacts on neonatal outcomes. Children born to insured mothers weighed 108 g higher and had reduced probability of low birth weight by 7.5 percentage points. These effects appear to be stronger for mothers with higher levels of education and in municipalities with a higher development index. Findings indicate that expanding insurance coverage could be helpful in improving neonatal outcomes in resource-constrained countries.

Carotenoid Biosynthetic Pathways Are Regulated by a Network of Multiple Cascades of Alternative Sigma Factors in Azospirillum brasilense Sp7.

Carotenoids constitute an important component of the defense system against photooxidative stress in bacteria. In Azospirillum brasilense Sp7, a nonphotosynthetic rhizobacterium, carotenoid synthesis is controlled by a pair of extracytoplasmic function sigma factors (RpoEs) and their cognate zinc-binding anti-sigma factors (ChrRs). Its genome harbors two copies of the gene encoding geranylgeranyl pyrophosphate synthase (CrtE), the first critical step in the carotenoid biosynthetic pathway in bacteria. Inactivation of each of two crtE paralogs found in A. brasilense caused reduction in carotenoid content, suggesting their involvement in carotenoid synthesis. However, the effect of crtE1 deletion was more pronounced than that of crtE2 deletion. Out of the five paralogs of rpoH in A. brasilense, overexpression of rpoH1 and rpoH2 enhanced carotenoid synthesis. Promoters of crtE2 and rpoH2 were found to be dependent on RpoH2 and RpoE1, respectively. Using a two-plasmid system in Escherichia coli, we have shown that the crtE2 gene of A. brasilense Sp7 is regulated by two cascades of sigma factors: one consisting of RpoE1and RpoH2 and the other consisting of RpoE2 and RpoH1. In addition, expression of crtE1 was upregulated indirectly by RpoE1 and RpoE2. This study shows, for the first time in any carotenoid-producing bacterium, that the regulation of carotenoid biosynthetic pathway involves a network of multiple cascades of alternative sigma factors. IMPORTANCE: Carotenoids play a very important role in coping with photooxidative stress in prokaryotes and eukaryotes. Although extracytoplasmic function (ECF) sigma factors are known to directly regulate the expression of carotenoid biosynthetic genes in bacteria, regulation of carotenoid biosynthesis by one or multiple cascades of sigma factors had not been reported. This study provides the first evidence of the involvement of multiple cascades of sigma factors in the regulation of carotenoid synthesis in any bacterium by showing the regulation of a gene encoding geranylgeranyl pyrophosphate synthase (crtE2) by RpoE1→RpoH2→CrtE2 and RpoE2→RpoH1→CrtE2 cascades in A. brasilense It also provides an insight into existence of an additional cascade or cascades regulating expression of another paralog of crtE.

Biogeographic specializations of two large hypotrich ciliates: Australocirrus shii and A. australis and proposed synonymy of Australocirrus and Cyrtohymenides.

Using standard methods, we studied the morphology and distribution of an Australian population of Australocirrus shii (Shi et al., 1997) nov. comb. and a Jamaican population of A. australis (Foissner, 1995) nov. comb. We identified three features, not or rarely used earlier, that distinguish Australocirrus shii from A. australis: the distance between the anterior pretransverse cirrus and the anteriormost transverse cirrus (5-8% vs. 1.5-1.7% of body length), the arrangement of the transverse cirri (3+2 vs. an oblique row), and the resting cyst macronuclear nodules (separate vs. fused). Australocirrus shii has been reported from Asia and Australia while A. australis is possibly restricted to the Neotropic. Because of problems in getting voucher materials of A. shii, we emphasise that permanent slides should be deposited in international repositories. Based on previous studies and new data, especially a refined interpretation of the shape of the paroral membrane, we suggest synonymy of Cyrtohymenides and Australocirrus. Thus, Cyrtohymena (Cyrtohymenides) shii, C. (Cyrtohymenides) aspoecki, and C. (Cyrtohymenides) australis are transferred to Australocirrus which is, inter alia, defined by a moderately to distinctly curved, but not recurved, paroral membrane, multiple fragmentation of dorsal kinety 3 and three or more dorsomarginal kineties.

Cross-talk between cognate and noncognate RpoE sigma factors and Zn(2+)-binding anti-sigma factors regulates photooxidative stress response in Azospirillum brasilense.

AIMS: Azospirillum brasilense harbors two redox-sensitive Zinc-binding anti-sigma (ZAS) factors (ChrR1 and ChrR2), which negatively regulate the activity of their cognate extra-cytoplasmic function (ECF) σ factors (RpoE1 and RpoE2) by occluding their binding to the core enzyme. Both pairs of RpoE-ChrR control responses to photooxidative stress. The aim of this study was to investigate whether the two RpoE-ChrR pairs cross-talk while responding to the stress. RESULTS: In silico analysis showed a high sequence similarity between ChrR1 and ChrR2 proteins, but differences in redox sensitivity. Using in silico and in vitro methods of protein-protein interaction, we have shown that both ChrR1 and ChrR2 proteins physically bind to their noncognate RpoE proteins. Restoration of the phenotypes of chrR1::Tn5 and chrR2::Km mutants related to carotenoid biosynthesis and photooxidative stress tolerance by expressing chrR1 or chrR2 provided in vivo evidence for the cross-talk. In addition, up- or down-regulation of several identical proteins by expressing chrR1 or chrR2 in the chrR1::Tn5 mutant provided another in vivo evidence for the cross-talk. INNOVATION: Although multiple redox-sensitive ZAS anti-σ factors occur in some Gram-positive bacteria, no cross-talk is reported among them. We report here, for the first time, that the two ZAS anti-σ factors of A. brasilense also interact with their noncognate σ factors and affect gene expression. CONCLUSION: The two redox-sensitive ZAS anti-σ factors in A. brasilense may interact with their cognate as well as noncognate ECF σ factors to play an important role in redox homeostasis by facilitating recovery from the oxidative stress.

A constitutively expressed pair of rpoE2-chrR2 in Azospirillum brasilense Sp7 is required for survival under antibiotic and oxidative stress.

Extracytoplasmic function (ECF) sigma factors (σ(E)) are known to bring about changes in gene expression to enable bacteria to adapt to different stresses. The Azospirillum brasilense Sp245 genome harbours nine genes encoding σ(E), of which two are adjacent to the genes encoding ChrR-type zinc-binding anti-sigma (ZAS) factors. We describe here the role and regulation of a new pair of rpoE-chrR, which was found in the genome of A. brasilense Sp7 in addition to the previously described rpoE-chrR pair (designated rpoE1-chrR1). The rpoE2-chrR2 pair is also cotranscribed, and their products show protein-protein interaction. The -10 and -35 promoter elements of rpoE2-chrR2 and rpoE1-chrR1 were similar but not identical. Unlike the promoter of rpoE1-chrR1, the rpoE2-chrR2 promoter was neither autoregulated nor induced by oxidative stress. Inactivation of chrR2 or overexpression of rpoE2 in A. brasilense Sp7 resulted in an overproduction of carotenoids. It also conferred resistance to oxidative stresses and antibiotics. By controlling the synthesis of carotenoids, initiation and elongation of translation, protein folding and purine biosynthesis, RpoE2 seems to play a crucial role in preventing and repairing the cellular damage caused by oxidative stress. Lack of autoregulation and constitutive expression of rpoE2-chrR2 suggest that RpoE2-ChrR2 may provide a rapid mechanism to cope with oxidative stress, wherein singlet oxygen ((1)O(2))-mediated dissociation of the RpoE2-ChrR2 complex might release RpoE2 to drive the expression of its target genes.

Bacteriophytochrome controls carotenoid-independent response to photodynamic stress in a non-photosynthetic rhizobacterium, Azospirillum brasilense Sp7.

Ever since the discovery of the role of bacteriophytochrome (BphP) in inducing carotenoid synthesis in Deinococcus radiodurans in response to light the role of BphPs in other non-photosynthetic bacteria is not clear yet. Azospirillum brasilense, a non-photosynthetic rhizobacterium, harbours a pair of BphPs out of which AbBphP1 is a homolog of AtBphP1 of Agrobacterium tumefaciens. By overexpression, purification, biochemical and spectral characterization we have shown that AbBphP1 is a photochromic bacteriophytochrome. Phenotypic study of the ΔAbBphP1 mutant showed that it is required for the survival of A. brasilense on minimal medium under red light. The mutant also showed reduced chemotaxis towards dicarboxylates and increased sensitivity to the photooxidative stress. Unlike D. radiodurans, AbBphP1 was not involved in controlling carotenoid synthesis. Proteome analysis of the ΔAbBphP1 indicated that AbBphP1 is involved in inducing a cellular response that enables A. brasilense in regenerating proteins that might be damaged due to photodynamic stress.

RpoH2 sigma factor controls the photooxidative stress response in a non-photosynthetic rhizobacterium, Azospirillum brasilense Sp7.

Bacteria belonging to the Alphaproteobacteria normally harbour multiple copies of the heat shock sigma factor (known as σ(32), σ(H) or RpoH). Azospirillum brasilense, a non-photosynthetic rhizobacterium, harbours five copies of rpoH genes, one of which is an rpoH2 homologue. The genes around the rpoH2 locus in A. brasilense show synteny with that found in rhizobia. The rpoH2 of A. brasilense was able to complement the temperature-sensitive phenotype of the Escherichia coli rpoH mutant. Inactivation of rpoH2 in A. brasilense results in increased sensitivity to methylene blue and to triphenyl tetrazolium chloride (TTC). Exposure of A. brasilense to TTC and the singlet oxygen-generating agent methylene blue induced several-fold higher expression of rpoH2. Comparison of the proteome of A. brasilense with its rpoH2 deletion mutant and with an A. brasilense strain overexpressing rpoH2 revealed chaperone GroEL, elongation factors (Ef-Tu and EF-G), peptidyl prolyl isomerase, and peptide methionine sulfoxide reductase as the major proteins whose expression was controlled by RpoH2. Here, we show that the RpoH2 sigma factor-controlled photooxidative stress response in A. brasilense is similar to that in the photosynthetic bacterium Rhodobacter sphaeroides, but that RpoH2 is not involved in the detoxification of methylglyoxal in A. brasilense.

An extracytoplasmic function sigma factor cotranscribed with its cognate anti-sigma factor confers tolerance to NaCl, ethanol and methylene blue in Azospirillum brasilense Sp7.

Azospirillum brasilense, a plant-growth-promoting rhizobacterium, is exposed to changes in its abiotic environment, including fluctuations in temperature, salinity, osmolarity, oxygen concentration and nutrient concentration, in the rhizosphere and in the soil. Since extra-cytoplasmic function (ECF) sigma factors play an important role in stress adaptation, we analysed the role of ECF sigma factor (also known as RpoE or σ(E)) in abiotic stress tolerance in A. brasilense. An in-frame rpoE deletion mutant of A. brasilense Sp7 was carotenoidless and slow-growing, and was sensitive to salt, ethanol and methylene blue stress. Expression of rpoE in the rpoE deletion mutant complemented the defects in growth, carotenoid biosynthesis and sensitivity to different stresses. Based on data from reverse transcriptase-PCR, a two-hybrid assay and a pull-down assay, we present evidence that rpoE is cotranscribed with chrR and the proteins synthesized from these two overlapping genes interact with each other. Identification of the transcription start site by 5' rapid amplification of cDNA ends showed that the rpoE-chrR operon was transcribed by two promoters. The proximal promoter was less active than the distal promoter, whose consensus sequence was characteristic of RpoE-dependent promoters found in alphaproteobacteria. Whereas the proximal promoter was RpoE-independent and constitutively expressed, the distal promoter was RpoE-dependent and strongly induced in response to stationary phase and elevated levels of ethanol, salt, heat and methylene blue. This study shows the involvement of RpoE in controlling carotenoid synthesis as well as in tolerance to some abiotic stresses in A. brasilense, which might be critical in the adaptation, survival and proliferation of this rhizobacterium in the soil and rhizosphere under stressful conditions.