Diamond Nanoparticles-Porphyrin mTHPP Conjugate as Photosensitizing Platform: Cytotoxicity and Antibacterial Activity.

Conjugation of photosensitizers (PS) with nanoparticles has been largely used as a strategy to stabilize PS in the biological medium resulting in photosensitizing nanoparticles of enhanced photoactivity. Herein, (Meso-5, 10, 15, 20-tetrakis (3-hydroxyphenyl) phorphyryn (mTHPP) was conjugated with diamond nanoparticles (ND) by covalent bond. Nanoconjugate ND-mTHPP showed suitable stability in aqueous suspension with 58 nm of hydrodynamic diameter and Zeta potential of -23 mV. The antibacterial activity of ND-mTHPP was evaluated against Escherichia coli for different incubation times (0-24 h). The optimal activity was observed after 2 h of incubation and irradiation (660 nm; 51 J/cm2) performed right after the addition of ND-mTHPP (100 µg/mL) to the bacterial suspension. The inhibitory activity was 56% whereas ampicillin at the same conditions provided only 14% of bacterial growth inhibition. SEM images showed agglomerate of ND-mTHPP adsorbed on the bacterial cell wall, suggesting that the antimicrobial activity of ND-mTHPP was afforded by inducing membrane damage. Cytotoxicity against murine embryonic fibroblast cells (MEF) was also evaluated and ND-mTHPP was shown to be noncytotoxic since viability of cells cultured for 24 h in the presence of the nanoconjugate (100 µg/mL) was 78%. Considering the enhanced antibacterial activity and the absence of cytotoxic effect, it is possible to consider the ND-mTHPP nanoconjugate as promising platform for application in antimicrobial photodynamic therapy (aPDT).

Synthesis of Phenyl Esters Using SiO2-SO3H Catalyst in Conventional Heating and Microwave-Irradiated Esterification Processes.

A SiO2-SO3H amorphous catalyst containing a small surface area of 115.0 m²g-1 and 1.32 mmol H+/g was prepared from fine construction sand and sodium carbonate and sulfonated with H2SO4. In a 10% (w/w) basis, it is very efficient for catalyzing the esterification of carboxylic acids with phenol. The reaction processes were performed using conventional heating and under microwave irradiation. The yields were higher in the microwave-irradiated esterification. The catalyst could be used for three esterification sequences in both processes.

Examining Proximal Risk Factors for Suicide in a Sample of Mexican Adults in Rehabilitation Centers.

The cross-cultural generalizability of the interpersonal theory of suicide was examined in this study. One hundred ninety-nine adults in an inpatient setting in Mexico completed the Personal Resources Questionnaire, Beck Hopelessness Scale, Interpersonal Needs Questionnaire, Acquired Capability for Suicide Scale, and Suicide Behaviors Questionnaire-Revised. Analyses revealed the interaction between perceived burdensomeness and thwarted belongingness did not predict suicide ideation. The interactions between perceived burdensomeness and thwarted belongingness and between perceived burdensomeness and acquired capacity significantly predicted suicidal behaviors, whereas the hypothesized three-way interaction did not. These findings highlight the importance of perceived burdensomeness in the development of suicidal behaviors among Mexican-origin adults.

Spanish translation and validation of the Interpersonal Needs Questionnaire.

The present study reports the multistage development and evaluation of a Spanish translation of the Interpersonal Needs Questionnaire (INQ). The INQ measures the constructs of thwarted belongingness and perceived burdensomeness, which the interpersonal theory of suicide proposes are proximal causes of suicidal desire. Participants were bilingual Hispanic college students in the United States (n = 56), heritage Spanish-speaking college students in the United States (n = 281), college students in Spain (n = 1,016), psychiatric inpatients in Mexico (n = 181), college students in Mexico (n = 239), and Spanish-speaking U.S. adults (n = 104). Results indicated that a 9-item 2-factor solution (INQ-S-9) provided good fit. Multiple group analyses were also consistent with measurement invariance across nationalities and clinical severity. Finally, both subscale scores demonstrated good internal consistency, test-retest reliability, convergent validity, and concurrent associations with scores on measures of suicide ideation. Cultural considerations and implications for use in clinical and research settings are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The preparation of benzyl esters using stoichiometric niobium (V) chloride versus niobium grafted SiO2 catalyst: A comparison study.

Two solvent free methods of a one-to-one alcohol/acid mol ratio synthesis of benzyl esters of the formic, acetic, benzoic, salicylic, nicotinic, and oxalic acids are described. The stoichiometric reactions used 1.5 mol ratio solid NbCl5 as the reagent and required from two to three hours for completion at room temperature; for the catalytic processes, NbCl5 was grafted directly, at room temperature, onto a silica gel of specific area of 507 m2g-1, produced from construction sand and sodium carbonate, forming a 5.4% Nb w/w SiO2-Nb gel with a specific area of 412 m2g-1. At 10% w/w catalyst/alcohol ratio, this SiO2-Nb catalyst gave similarly very good yields but required from 6 to 9 hours at the reflux temperature of the slurry. The catalyst could be re-used three times.

Host specificity and the structure of helminth parasite communities of fishes in a Neotropical river in Mexico.

In a tropical locality of Río La Antigua, Veracruz, Mexico, 11 fish species, represented by 244 individual fish from six freshwater fish families living sympatrically and synchronically, were examined for helminth parasites. A total of 36 taxa of helminths were recorded, 24 autogenic and 12 allogenic forms, including 6 monogeneans, 14 trematodes, 1 cestode, and 15 nematodes. Most helminth taxa were recovered for 10/11 of the component communities we analyzed. The results contribute empirical evidence that host specificity is an important force in the development of helminth communities of freshwater fishes. Each fish family has their own set of parasites, host species belonging to the same taxon share parasite species. High component community similarity among related host species was recorded, demonstrated by high prevalence and abundance, as well as dominance, of autogenic specialist species in each component community. Most autogenic helminth species are numerically and reproductively successful in relatively few host species. Autogenic helminths common in one host species are not common in others. Our findings give empirical support to the idea that low levels of sharing of parasites favor animal coexistence and high species richness, because large phylogenetic differences allow potentially competing animals to consume the same resources without being sensitive of another's parasites.