Boron-π interactions in two 3-(dihydroxyboryl)anilinium salts analyzed by crystallographic studies and supported by the noncovalent interactions (NCI) index theoretical approach.

In the title compounds, 3-(dihydroxyboryl)anilinium bisulfate monohydrate, C6H9BNO2+·HSO4-·H2O (I), and 3-(dihydroxyboryl)anilinium methyl sulfate, C6H9BNO2+·CH3SO4- (II), the almost planar boronic acid molecules are linked by pairs of O-H...O hydrogen bonds, forming centrosymmetric motifs that can be described by the graph-set R22(8) motif. In both crystals, the B(OH)2 group acquires a syn-anti conformation (with respect to the H atoms). The presence of the hydrogen-bonding functional groups B(OH)2, NH3+, HSO4-, CH3SO4- and H2O generates three-dimensional hydrogen-bonded networks, in which the bisulfate (HSO4-) and methyl sulfate (CH3SO4-) counter-ions act as the central building blocks within the crystal structures. Furthermore, in both structures, the packing is stabilized by weak boron-π interactions, as shown by noncovalent interactions (NCI) index calculations.

The identification of byproducts from the catalytic reduction reaction of 4-nitrophenol to 4-aminophenol: A systematic spectroscopic study.

Acetaminophenol, commonly recognized as paracetamol (considered safer than aspirin) is formed by nitration of phenol (4-nitrophenol (4-NP)) for its conversion to 4-aminophenol (4-AP), followed by the acetylation for the final product. As 4-NP is an intermediate product in acetaminophenol (paracetamol) production from phenol the dynamic analysis of acetylation of amine group is important. This study focuses on the feasibility of spectroscopic studies to monitor the removal of 4-NP using sodium borohydride (NaBH4) probe reaction in the presence of silver, gold, and bimetallic Ag/Au nanoparticles. UV-visible absorbance and fluorescence spectroscopy measurements reveal the formation of 1,4-benzoquinone (BQ), hydroquinone (HQ), and phenol (Ph) as the final products, in addition to the formation of typically reported 4-AP. The intermediates of NaBH4 seem to play a significant role in the formation of BQ, which converts to HQ in the basic medium followed by the formation of phenol in an acidic medium. Complete kinetic analysis with respect to spectroscopic studies of the standard compounds is presented. Similar results were obtained with 4-NP spiked river and seawater samples. The present findings may lead to catalytic benchmarking that can differ from most of the current practices and highlight the importance of adopting a holistic approach towards the fundamental understanding of 4-NP catalytic reduction that must take into account the concentration of NaBH4 and pH interdependencies.

Further Approaches in the Design of Antitumor Agents with Response to Cell Resistance: Looking toward Aza Crown Ether-dtc Complexes.

The dianionic aza crown ether-dtc N,N'-bis(dithiocarbamate)-1,10-diaza-18-crown-6 (L2-) is a versatile ligand capable of yielding binuclear complexes with group 10 elements, also known as Ni-triade, [µ-(κ2-S,-S'-L)M2(PPh3)4]Cl2 (M = Pd (1), Pt (2)), [µ-(κ2-S,-S'-L)M2(PPh3)4](BPh4)2 (M = Pd (3), Pt (4)), and µ-(κ-S,-S'-L)Ni2(PPh3)2Cl2 (5), and has proven to be an excellent option to the design of metal-based drugs able to provide multiple response to cell resistance. Palladium and platinum complexes, 1 and 2, were tested for cytotoxicity in the human cervix carcinoma cell line HeLa-229, the human ovarian carcinoma cell line A2780, and the cisplatin-resistant mutant A2780cis, finding significant activity toward all three cancer cell lines, with low micromolar IC50 values, comparable to cisplatin. Markedly, against the cisplatin resistant cell line A2780cis, compound 2 exhibits better cytotoxic activity than the clinical drug (IC50 = 2.3 ± 0.2 µM for 2 versus 3.6 ± 0.5 µM for cisplatin). Moreover, an enhancement of the antitumor response is achieved when adding an equimolar amount of alkali metal chloride (NaCl or KCl) to the medium, for instance, testing compound 1 against the cisplatin-resistant A2780cis cells, the IC50 decreases from 9.3 ± 0.4 to 7.4 ± 0.3 and 5.4 ± 0.1 µM, respectively, after addition of the salt solution. For the platinum derivative 2, the IC50 improves by ca. 40% reaching 1.3 ± 0.1 µM when potassium chloride is added. Likewise, the resistant factor found for 2 (RF = 1) confirms that this complex circumvents cisplatin-resistance in A2780cis and is improved with the addition of potassium chloride (RF = 0.65). The presence of the aza crown ether moiety as linker in the systems studied herein is a key point since, in addition to allowing and facilitating interaction with alkali metal ions, this unit is flexible enough to adapt to a variety of environments, as confirmed by the X-ray crystal structures described, where different conformations and ways to fold in are found. In order to gain insight into the electronic and structural facts involved in the interaction of complex 2 with the alkali metal ions, a DFT study was performed, and the description of the molecular electrostatic potentials (MEPs) is also presented.

Transport of 14C-prosulfocarb through soil columns under different amendment, herbicide incubation and irrigation regimes.

This study sets out to evaluate the effect on the leaching of prosulfocarb through packed soil columns of applying green compost (GC) as an organic amendment (20% w/w), herbicide ageing over 28 days in the soil (incubation vs. no incubation), and two different irrigation regimes (saturated or saturated-unsaturated flows). Peak concentrations decreased after herbicide incubation in the columns for both unamended (S) and amended (S + GC) soils under both flow regimes. The leached amounts decreased when the herbicide was incubated for 28 days in S (2.1 and 1.9 times) and S + GC (2.9 and 1.6 times), under saturated or saturated-unsaturated flow, respectively. In the S columns, the total amounts retained (43.3%-60.8%) were lower than the ones obtained for the S + GC columns under saturated flow (77.4%-85.2%), suggesting a stronger interaction between the herbicide and the GC-amended soil. This behaviour was not observed under saturated-unsaturated flow, as the total amounts retained were similar in both the S and S + GC columns. Prosulfocarb was primarily retained in the first segment of the S (>28%) and S + GC (>43%) columns under all conditions. Incubation time did not greatly affect the herbicide retention, but it significantly increased the mineralized amount under saturated flow. The total balances of 14C-prosulfocarb were >73% and >80% in the S and S + GC columns, respectively, indicating that amendment decreased prosulfocarb loss by volatilization. Several factors, such as amendment, herbicide ageing and water flow, proved to be important for controlling the leaching of this herbicide through the soil profile.

Nitrogen-Doped Graphene Oxide Dots-Based "Turn-OFF" H2O2, Au(III), and "Turn-OFF-ON" Hg(II) Sensors as Logic Gates and Molecular Keypad Locks.

Fluorescent nitrogen-doped graphene oxide dots (NGODs) have been demonstrated as an on-off nanosensor for the detection of Hg2+, Au3+, and H2O2. As compared to l-cystine, where the luminescence signal recovery results from the detachment of Hg2+ from the NGODs, signal recovery through l-ascorbic acid (turn-off-on model) has been attributed to the reduction of Hg2+ to Hg0. The sustainable recovery of the photoluminescence signal is demonstrated using common citrus fruits containing vitamin C (l-AA), suggesting a promising practical usage of this sensing system. Additionally, the sensitivity of NGOD- and AA-originated signal recovery from the Hg(II)-NGODs mixture has been successfully tested in Hg2+ ion-spiked tap water from three different places. Mimic devices were executed and verified on the basis of characteristic spectral changes, and the possible utility of this system in electronic security and memory element devices has also been demonstrated. Considering an easy synthesis process and excellent performance of NGODs, this investigation opens up new opportunities for preparing high-quality fluorescent NGODs to meet the requirements of many applications.

Assessment of 14C-prosulfocarb dissipation mechanism in soil after amendment and its impact on the microbial community.

Adding organic amendments to soil could modify the bioavailability of herbicides and lead to changes in the microbial community's activity and structure. The objective here was to study the dissipation and total mass balance of 14C-labeled prosulfocarb applied at two rates (4 and 10 mg kg-1) in unamended and green compost (GC)-amended soil. Soil dehydrogenase activity (DHA) and phospholipid fatty acid (PLFA) profile analysis were determined to evaluate the effect of herbicide residues on microbial community's activity and structure over the dissipation period. The dissipation rate of prosulfocarb decreased after soil amendment due to higher herbicide adsorption by the amended soil. The 50% dissipation time (DT50) increased 1.7 times in the unamended soil when the concentration of prosulfocarb increased 2.5 times. The mass balance results indicate that the sum of water and organic extractable fractions represented the highest amounts up to the dissipation of 50% 14C-prosulfocarb. The 14C-herbicide was then mainly mineralized (up to 11%-31%) or formed non-extractable residues (up to 35%-44%). The amount of 14C-prosulfocarb residues extracted with methanol was slightly higher in amended soils than in unamended ones. 14C-prosulfocarb mineralization was higher in unamended soils than in amended ones. The formation of non-extractable residues was continuous, and increased over time. Soil DHA decreased in the unamended soil and was maintained in the GC-amended soil at the end of the assay. The microbial structure was barely disturbed over the prosulfocarb degradation process, although it was clearly influenced by the application of GC. The results obtained reveal the influence organic amendment has on herbicide bioavailability to decrease its biodegradation and buffer its impact on the soil microbial structure.

Legibilidad, relevancia y calidad de la información en español en la Web para pacientes con artritis reumatoide / Readability, relevance and quality of the information in Spanish on the Web for patients with rheumatoid arthritis

La educación es un determinante mayor de salud y uno de los predictores independientes de desenlace en artritis reumatoide (AR). El uso del Internet por pacientes ha crecido en forma exponencial en la última década. Objetivos. Evaluar las características, legibilidad y calidad de la información disponible en Internet en idioma español en relación con la AR. Material y métodos. Se buscó la frase AR en Google. Se evaluaron las primeras 30 páginas de resultados de acuerdo con un formato diseñado ex profeso (relevancia, autoría, tipo de publicación, enfermedad discutida e interés financiero); además se evaluaron la calidad y la legibilidad de las páginas, con las herramientas DISCERN e INFLESZ, respectivamente. La extracción de datos se realizó por médicos pasantes y la evaluación fue por consenso. Resultados. Se obtuvieron 323 resultados, pero solo el 63% de ellos fueron relevantes; el 80% de estos fueron sitios de información (71% discutían exclusivamente AR, 44% terapia convencional y 12% terapias alternativas). Un 12,5% tenía interés financiero. El 60% de los sitios fueron creados por organizaciones no lucrativas y 15% por asociaciones médicas. Las asociaciones médicas de Estados Unidos de América se posicionan mejor en español (Arthritis Foundation en la posición 4 y el American College of Rheumatology en la 10) que los sitios web de países de habla hispana. Conclusiones. Existe riesgo de desinformación para los pacientes con AR que utilizan la Web. Se identifica además áreas de oportunidad para instituciones médicas de países de habla hispana para tener un mayor involucramiento social en la educación de sus pacientes (AU)

Background. Education is a major health determinant and one of the main independent outcome predictors in rheumatoid arthritis (RA). The use of the Internet by patients has grown exponentially in the last decade. Objective. To assess the characteristics, legibility and quality of the information available in Spanish in the Internet regarding to rheumatoid arthritis. Material and methods. The search was performed in Google using the phrase rheumatoid arthritis. Information from the first 30 pages was evaluated according to a pre-established format (relevance, scope, authorship, type of publication and financial objective). The quality and legibility of the pages were assessed using two validated tools, DISCERN and INFLESZ respectively. Data extraction was performed by senior medical students and evaluation was achieved by consensus. Results. The Google search returned 323 hits but only 63% were considered relevant; 80% of them were information sites (71% discussed exclusively RA, 44% conventional treatment and 12% alternative therapies) and 12.5% had a primary financial interest. 60% of the sites were created by nonprofit organizations and 15% by medical associations. Web sites posted by medical institutions from the United States of America were better positioned in Spanish (Arthritis Foundation 4th position and American College of Rheumatology 10th position) than web sites posted by Spanish speaking countries. Conclusions. There is a risk of disinformation for patients with RA that use the Internet. We identified a window of opportunity for rheumatology medical institutions from Spanish-speaking countries to have a more prominent societal involvement in the education of their patients with RA (AU)

Readability, relevance and quality of the information in Spanish on the Web for patients with rheumatoid arthritis. / Legibilidad, relevancia y calidad de la información en español en la Web para pacientes con artritis reumatoide.

BACKGROUND: Education is a major health determinant and one of the main independent outcome predictors in rheumatoid arthritis (RA). The use of the Internet by patients has grown exponentially in the last decade. OBJECTIVE: To assess the characteristics, legibility and quality of the information available in Spanish in the Internet regarding to rheumatoid arthritis. MATERIAL AND METHODS: The search was performed in Google using the phrase rheumatoid arthritis. Information from the first 30 pages was evaluated according to a pre-established format (relevance, scope, authorship, type of publication and financial objective). The quality and legibility of the pages were assessed using two validated tools, DISCERN and INFLESZ respectively. Data extraction was performed by senior medical students and evaluation was achieved by consensus. RESULTS: The Google search returned 323 hits but only 63% were considered relevant; 80% of them were information sites (71% discussed exclusively RA, 44% conventional treatment and 12% alternative therapies) and 12.5% had a primary financial interest. 60% of the sites were created by nonprofit organizations and 15% by medical associations. Web sites posted by medical institutions from the United States of America were better positioned in Spanish (Arthritis Foundation 4th position and American College of Rheumatology 10th position) than web sites posted by Spanish speaking countries. CONCLUSIONS: There is a risk of disinformation for patients with RA that use the Internet. We identified a window of opportunity for rheumatology medical institutions from Spanish-speaking countries to have a more prominent societal involvement in the education of their patients with RA.

Fifteen-year trend in information on the World Wide Web for patients with rheumatoid arthritis: evolving, but opportunities for improvement remain.

The aim of this study was to assess the changes in the characteristics of rheumatoid arthritis information on the Internet over a 15-year period and the positioning of Web sites posted by universities, hospitals, and medical associations. We replicated the methods of a 2001 study assessing rheumatoid arthritis information on the Internet using WebCrawler. All Web sites and pages were critically assessed for relevance, scope, authorship, type of publication, and financial objectives. Differences between studies were considered significant if 95 % confidence intervals did not overlap. Additionally, we added a Google search with assessments of the quality of content of web pages and of the Web sites posted by medical institutions. There were significant differences between the present study's WebCrawler search and the 2001-referent study. There were increases in information sites (82 vs 36 %) and rheumatoid arthritis-specific discussion pages (59 vs 8 %), and decreases in advertisements (2 vs 48 %) and alternative therapies (27 vs 45 %). The quality of content of web pages is still dispersed; just 37 % were rated as good. Among the first 300 hits, 30 (10 %) were posted by medical institutions, 17 of them in the USA. Regarding readability, 7 % of these 30 web pages required 6 years, 27 % required 7-9 years, 27 % required 10-12 years, and 40 % required 12 or more years of schooling. The Internet has evolved in the last 15 years. Medical institutions are also better positioned. However, there are still areas for improvement, such as the quality of the content, leadership of medical institutions, and readability of information.

Crystal structure of 1,3-di-cyclo-hexyl-1-[3-(pyren-1-yl)prop-anoyl]urea.

In the title compound, C33H38N2O2, each of the cyclo-hexyl rings adopts a chair conformation. The two planes involving carbonyl groups, C-(C=O)-N and N-(C=O)-N, are oriented at a dihedral angle of 62.28 (10)°. In the crystal, two neighboring mol-ecules are linked by a pair of N-H⋯O inter-actions, generating an inversion dimer. The dimers are inter-connected by C-H⋯O hydrogen bonds into a supra-molecular chain along the a-axis direction.

Selective fluorometric detection of pyrophosphate by 3-hydroxyflavone-diphenyltin(IV) complex in aqueous micellar medium.

3-Hydroxyflavonate-diphenyltin(IV) chloride (Ph(2)Sn(Ofl)Cl) was prepared and characterized structurally by single crystal X-ray diffraction. The compound possesses high fluorescence (λ(max) 464 nm with excitation at 400 nm) in neutral aqueous solutions containing 5 mM cetyltrimethylammonium chloride and does not lose the flavonol ligand even at high dilution. The fluorescence is selectively quenched by pyrophosphate (PPi) (linear range 0-5 µM, detection limit 0.1 µM). Determination of 1 µM PPi tolerates the presence of 100-fold excess of AMP, ADP, inorganic phosphate and acetate, and 10-fold excess of ATP. From concentration profiles of the quenching effect it is concluded that quenching occurs due to formation of the complex (Ph(2)Sn(Ofl))(3)PPi, which is transformed at higher PPi concentrations to a simple 1 : 1 complex Ph(2)Sn(Ofl)(PPi). No flavonol ligand exchange with PPi is observed. A series of related organotin(IV) complexes were prepared in situ by reacting 3-hydroxyflavone with Me(2)SnCl(2), PhSnCl(3) and n-BuSnCl(3). The derivatives of Me(2)SnCl(2) and PhSnCl(3) behave similarly to Ph(2)Sn(Ofl)Cl but with lower sensitivity to PPi. However, the n-butyltin(IV) derivative tentatively of the composition n-BuSn(Ofl)(2) undergoes fluorescence enhancement rather than quenching in the presence of PPi in the µM concentration range. The results of this study demonstrate that the use of metal flavonol complexes as optical sensors for anions is a promising approach.

Isolation and characterization of a new dimeric esterase from Lactobacillus sakei 23K.

The M(w) of a Lactobacillus sakei intracellular esterase, determined by gel filtration, was compared to those obtained from SDS-PAGE or MALDI-TOF, pointing to a dimeric structure. Its N-terminal sequence and peptide mass fingerprint suggest that it is the putative LSA044 protein from L. sakei 23K genome.

Study of a sterol esterase secreted by Ophiostoma piceae: sequence, model and biochemical properties.

An extracellular sterol esterase from Ophiostoma piceae efficiently hydrolyzes sterol esters, triglycerides and p-nitrophenol esters. cDNA was screened with a probe obtained by PCR using as primers oligonucleotides corresponding to the N-terminal and internal mature enzyme sequences and complete sequence was obtained by 3' rapid amplification of cDNA end (RACE) and inverse PCR. The O. piceae esterase gene had a length of 1.8 kbp and lacked introns. A search for proteins with related amino acid sequences revealed around 40% identity with lipases from Candida rugosa and Geotrichum candidum. Modelling the O. piceae enzyme, using the crystal structures of Lip1 and Lip3 from C. rugosa as templates, revealed a similar substrate-binding site, but some changes affecting the flap zone and the aromatic region of the tunnel may be responsible for the wide substrate specificity of this interesting sterol esterase. The ability of the new fungal esterase to hydrolyze triglycerides and esters of p-nitrophenol and cholesterol was compared with those of commercial lipases and cholesterol esterases showing the new enzyme the highest efficiency hydrolyzing triglycerides and sterol esters in the conditions assayed (in presence of Genapol X-100). Finally, the O. piceae gene was successfully expressed in Pichia pastoris, as a model organism to express fungal enzymes, resulting in higher levels of esterase activity than those obtained in the O. piceae cultures. In spite of its higher glycosylation degree, the recombinant enzyme was able to hydrolyze more efficiently than native enzyme the assayed substrates.

Boron macrocycles having a calix-like shape. Synthesis, characterization, X-ray analysis, and inclusion properties.

The syntheses, structure, and inclusion properties of trinuclear boron compounds having a calix-like shape are described. The compounds have been obtained via self-assembly reactions between salicylaldehyde derivatives and 3-aminophenylboronic acid, whereby the formation of three N --> B coordination bonds favored the oligomerization. The products have high melting points (>370 degrees C), are stable to moisture, and have good solubility in organic solvents; the latter property is useful for host-guest recognition experiments. The structural analysis by X-ray diffraction revealed that diverse conformations are possible because of the presence of two different units of aromatic rims. A cone-cone (double-cone) conformation is observed for three of these compounds, while the remaining one has a cone-partial cone conformation. An analysis of the molecular packing showed that the molecules are stacked in columns in two different orientations in relation to the organization of the macrocycles when referred to the N-B bonds. The inclusion properties toward primary amines and ammonium chlorides were analyzed by titration experiments and monitored by UV spectroscopy, whereby association constants on the order of 10(2)-10(3) M(-1) were determined.

Structural relationship between a host included chain of spirocyclic water hexamers and bulk water--the role of water clusters in self assembly and crystallization processes.

Infinite chains of spirocyclic water hexamers are included in the crystal lattice of a tin complex with a curved, hydrophobic surface and only weak intermolecular bonding interactions between the host molecules, so that the enclosed water clusters might be reminiscent of the solvation sphere in solution.

Synthesis, characterization, biocide and toxicological activities of di-n-butyl- and diphenyl-tin(IV)-salicyliden-beta-amino alcohol derivatives.

The one pot reaction of salicylaldehyde 1, beta-amino alcohols 2a-2c, and di-n-butyltin(IV) oxide 3a or diphenyltin(IV) oxide 3b produced five diorganotin(IV) compounds, 4a-4c, 5a, and 5c, in good yields. All compounds were characterized by IR, (1)H, (13)C, and (119)Sn NMR spectroscopy, and elemental analysis; furthermore, compounds 4b, 4c, 5a, and 5c were characterized by X-ray diffraction analysis. After the structural characterization, all of the compounds were tested in vitro against Bacillus subtilis (Gram-positive, strain ATCC 6633), Escherichia coli (Gram-negative, strain DH5alpha), Pseudomonas aeruginosa (Gram-negative, strain BH3), Desulfovibrio longus (strain DSM 6739), and Desulfomicrobium aspheronum (strain DSM 5918) to assess their antimicrobial activity. Compounds 4 and 5 demonstrated a wide range of bactericidal activities against the tested aerobic (one Gram-positive and two Gram-negative subtypes) and anaerobic bacteria (two sulfate-reducing bacteria, SRB). Compound 5 had better bactericidal performances than compound 4. For all of the compounds, the acute toxicity was measured using luminescent bacteria toxicity (LBT-Microtox) tests to track their further environmental impact. According to these results and in order to fulfill environmental regulations, the toxicity of the compounds studied herein can be modulated through the proper selection of the disubstituted tin(IV) moiety.

Nanocap-shaped tin phthalocyanines: synthesis, characterization, and corrosion inhibition activity.

Thermal and microwave reactions between [PcSn(IV)Cl2] (1) and the potassium salts of eight fatty acids (2 a-h) led to cis-[(RCO2)2Sn(IV)Pc] compounds (3 a-h) in yields ranging from 54 to 90 %. Compounds 3 a-h were fully characterized by elemental analysis, spectroscopy (IR, UV/Vis, multinuclear NMR), and seven X-ray diffraction structures, whereby two different allotropes were observed in two cases. The two carboxylates in 3 have a cis anisobidentate binding mode, octacoordination of the tin atoms with square-antiprismatic geometry, and pi-electron-rich nanocap shapes. On account of the latter characteristics, 3 a-h compounds have anticorrosion properties. LPR and Tafel electrochemical methods were used to characterize the behavior of these derivatives in naturally aerated sour brine, which is a common environment in petroleum production and refinery operations. The measurement of the corrosion rate of carbon steel AISI 1018 in the presence of 3 a-h (500 ppm) gave efficiencies of 61-87 % for the inhibitor performance. Of the different derivatives examined, compounds 3 e and 3 h were the most effective corrosion inhibitor prototypes.

Boron-nitrogen macrocycles: a new generation of calix[3]arenes.

The simple condensation reaction of 3,5-di-tert-butyl salicylaldehyde and 3-aminophenylboronic acid leads to a trimeric macrocyclic compound. The ability of this molecule to include small organic molecules was in a first approximation analyzed by (1)H NMR spectroscopy and X-ray crystallography.

Microwave assisted stereoselective synthesis of cis-substituted TinIV phthalocyanine dicarboxylates. application as corrosion inhibitors.

Two PcSn(IV) dicarboxylate molecules were obtained through efficient microwave methodology with the aim to test them as corrosion inhibitors in the oil industry. The compounds were characterized by elemental analysis, IR, UV-vis, (1)H, (13)C NMR, and X-ray diffraction. The relative configuration of the two carboxylates is cis, placing the fatty acid moieties on the same face of the phthalocyanine macrocycle. In the solid-state the tin atoms possess square antiprismatic octacoordinated geometries. Both tin phthalocyanines were tested as corrosion inhibitors for hydrogen sulfide corrosive media showing a chemisorption process of the nanocap motifs on the metallic surface. Apparently, the length of the hydrophobic chain contributes significantly to the inhibition efficiency, in the sense that shorter chains increase the efficiency.