Chemical synthesis and optical, structural, and surface characterization of InP-In2O3 quantum dots.

InP-In2O3 colloidal quantum dots (QDs) synthesized by a single-step chemical method without injection of hot precursors (one-pot) were investigated. Specifically, the effect of the tris(trimethylsilyl)phosphine, P(TMS)3, precursor concentration on the QDs properties was studied to effectively control the size and shape of the samples with a minimum size dispersion. The effect of the P(TMS)3 precursor concentration on the optical, structural, chemical surface, and electronic properties of InP-In2O3 QDs is discussed. The absorption spectra of InP-In2O3 colloids, obtained by both UV-Vis spectrophotometry and photoacoustic spectroscopy, showed a red-shift in the high-energy regime as the concentration of the P(TMS)3 increased. In addition, these results were used to determine the band-gap energy of the InP-In2O3 nanoparticles, which changed between 2.0 and 2.9 eV. This was confirmed by Photoluminescence spectroscopy, where a broad-band emission displayed from 2.0 to 2.9 eV is associated with the excitonic transition of the InP and In2O3 QDs. In2O3 and InP QDs with diameters ranging approximately from 8 to 10 nm and 6 to 9 nm were respectively found by HR-TEM. The formation of the InP and In2O3 phases was confirmed by X-ray Photoelectron Spectroscopy.

Tracing the phylogenetic history of the Crl regulon through the Bacteria and Archaea genomes.

BACKGROUND: Crl, identified for curli production, is a small transcription factor that stimulates the association of the σS factor (RpoS) with the RNA polymerase core through direct and specific interactions, increasing the transcription rate of genes during the transition from exponential to stationary phase at low temperatures, using indole as an effector molecule. The lack of a comprehensive collection of information on the Crl regulon makes it difficult to identify a dominant function of Crl and to generate any hypotheses concerning its taxonomical distribution in archaeal and bacterial organisms. RESULTS: In this work, based on a systematic literature review, we identified the first comprehensive dataset of 86 genes under the control of Crl in the bacterium Escherichia coli K-12; those genes correspond to 40% of the σS regulon in this bacterium. Based on an analysis of orthologs in 18 archaeal and 69 bacterial taxonomical divisions and using E. coli K-12 as a framework, we suggest three main events that resulted in this regulon's actual form: (i) in a first step, rpoS, a gene widely distributed in bacteria and archaea cellular domains, was recruited to regulate genes involved in ancient metabolic processes, such as those associated with glycolysis and the tricarboxylic acid cycle; (ii) in a second step, the regulon recruited those genes involved in metabolic processes, which are mainly taxonomically constrained to Proteobacteria, with some secondary losses, such as those genes involved in responses to stress or starvation and cell adhesion, among others; and (iii) in a posterior step, Crl might have been recruited in Enterobacteriaceae; because its taxonomical pattern constrained to this bacterial order, however further analysis are necessary. CONCLUSIONS: Therefore, we suggest that the regulon Crl is highly flexible for phenotypic adaptation, probably as consequence of the diverse growth environments associated with all organisms in which members of this regulatory network are present.

Improving potato drought tolerance through the induction of long-term water stress memory.

Knowledge of drought tolerance in potato is limited and very little is known about stress memory in this crop. In the present study, long-term stress memory was tested on tuber yield and drought tolerance related traits in three potato varieties (Unica, Désirée and Sarnav) with contrasted yields under water restriction. Seed tubers produced by plants grown under non-restricted (non-primed tubers) and restricted (primed tubers) water conditions were sown and exposed to similar watering treatments. Tuber yield and leaf greenness of plants from primed and non-primed seeds as well as tuber carbon isotope discrimination (Δ(13)C) and antioxidant activity (AA) responses to watering treatments were compared. Higher tuber yield, both under non-restricted and restricted water regimes, was produced by primed Sarnav plants. The decrease of tuber yield and Δ(13)C with water restriction was lower in primed Unica plants. Long-term stress memory consequently appears to be highly genotype-dependent in potato. Its expression in plants originated from primed tubers and facing water restriction seems to be positively associated to the degree of inherent capability of the cultivar to yield under water restriction. However, other effects of priming appear to be genotype-independent as priming enhanced the tuber AA in response to water restriction in the three varieties.

In vivo corrosion, tumor outcome, and microarray gene expression for two types of muscle-implanted tungsten alloys.

Tungsten alloys are composed of tungsten microparticles embedded in a solid matrix of transition metals such as nickel, cobalt, or iron. To understand the toxicology of these alloys, male F344 rats were intramuscularly implanted with pellets of tungsten/nickel/cobalt, tungsten/nickel/iron, or pure tungsten, with tantalum pellets as a negative control. Between 6 and 12 months, aggressive rhabdomyosarcomas formed around tungsten/nickel/cobalt pellets, while those of tungsten/nickel/iron or pure tungsten did not cause cancers. Electron microscopy showed a progressive corrosion of the matrix phase of tungsten/nickel/cobalt pellets over 6 months, accompanied by high urinary concentrations of nickel and cobalt. In contrast, non-carcinogenic tungsten/nickel/iron pellets were minimally corroded and urinary metals were low; these pellets having developed a surface oxide layer in vivo that may have restricted the mobilization of carcinogenic nickel. Microarray analysis of tumors revealed large changes in gene expression compared with normal muscle, with biological processes involving the cell cycle significantly up-regulated and those involved with muscle development and differentiation significantly down-regulated. Top KEGG pathways disrupted were adherens junction, p53 signaling, and the cell cycle. Chromosomal enrichment analysis of genes showed a highly significant impact at cytoband 7q22 (chromosome 7) which included mouse double minute (MDM2) and cyclin-dependant kinase (CDK4) as well as other genes associated with human sarcomas. In conclusion, the tumorigenic potential of implanted tungsten alloys is related to mobilization of carcinogenic metals nickel and cobalt from corroding pellets, while gene expression changes in the consequent tumors are similar to radiation induced animal sarcomas as well as sporadic human sarcomas.

Synergic adsorption in the simultaneous removal of acid blue 25 and heavy metals from water using a Ca(PO3)2-modified carbon.

We report the simultaneous adsorption of acid blue 25 dye (AB25) and heavy metals (Zn(2+), Ni(2+) and Cd(2+)) on a low-cost activated carbon, whose adsorption properties have been improved via a surface chemistry modification using a calcium solution extracted from egg shell wastes. Specifically, we have studied the removal performance of this adsorbent using the binary aqueous systems: AB25-Cd(2+), AB25-Ni(2+) and AB25-Zn(2+). Multi-component kinetic and equilibrium experiments have been performed and used to identify and characterize the synergic adsorption in the simultaneous removal of these pollutants. Our results show that the presence of AB25 significantly favors the removal of heavy metals and may increase the adsorption capacities up to six times with respect to the results obtained using the mono-cationic metallic systems, while the adsorption capacities of AB25 are not affected by the presence of metallic ions. It appears that this anionic dye favors the electrostatic interactions with heavy metals or may create new specific sites for adsorption process. In particular, heavy metals may interact with the -SO(3)(-) group of AB25 and to the hydroxyl and phosphoric groups of this adsorbent. A response surface methodology model has been successfully used for fitting multi-component adsorption data.

[Non Hodgkin lymphoma of the sigmoid colon: case report]. / Linfoma no Hodgkin de sigmoides: reporte de un caso.

Non-Hodgkin lymphoma (NHL) occurs in extranodal location in approximately 20% of patients with limited stage, high-grade disease. Colon is infrequently involved as a primary location, accounting for 4% of all extranodal NHL and far less than 1% of all colonic malignancies. Colonic NHL differs significantly in terms of presentation, therapy and outcome relative to other more common gastrointestinal sites, like stomach or small bowel. The most common location is the cecum (60-74% of cases), while the sigmoid is involved in 2.5-14%. Largely related to the lack of specific signs and symptoms, patients frequently present advanced locoregional disease. Moreover, more than half of patients require an emergent surgery, usually due to pain, bleeding, or obstruction. Therapy usually involves resection of the affected colon and regional lymph nodes followed by adjuvant chemotherapy or/and radiotherapy. Utilizing this approach 5 years survival rates range between 27-55%. We present a 59 years old man with weight loss,abdominal pain, palpable mass and intestinal obstruction. A sigmoidectomy was realized with histopathologic report of NHL. Systemic adjuvant chemotherapy and abdominal radiation were administered. After a 6 month follow-up from initial procedure he is now asymptomatic with Karnofsky of 90. Therefore a surgeon should consider the possibility of NHL when evaluating such patients.

[Mixedematous ileus; acute abdomen exacerbate.]. / Ileo mixedematoso;exacerbante de abdomen agudo.

The surgical literature contains few reports about effects of hypothyroidism in patients with acute abdomen; has been reported that a glycoprotein infiltrate the lining of the bowel leading to denervation. We report the case of a woman with acute abdomen secondary to pyosalpynx with uncontrolled hypothyroidism postoperative complications.Hypothyroidism is called "big mimicker"because its clinic spectrum ranges from anasymptomatic subclinical condition to the rare,life-threatening myxedema coma, and thus can bea challenging diagnosis to make. Unrecognized hypothyroidism may lead to unnecessary surgery or even a potentially fatal outcome. A heightened awareness of this not so uncommon entity is mandatory

[Rectal endometriosis: entity difficult to diagnose.]. / Endometriosis rectal:entidad de difícil diagnóstico.

Endometriosis is a gynecologic disorder characterized by the presence of endometrial glands and stroma outside the endometrial cavity and the uterine musculature. Although the ectopic endometriotic implants are most commonly found in the pelvis, the GI tract is the most common site of extrapelvic endometriosis The diagnosis of rectosigmoid is difficult to make on colonoscopy because of the subepithelial location of the endometriotic implants. We present a case report ofa 38-years-old woman referred with a diagnosis of rectal cancer with large intestine symptoms.Rectal endometriosis should be considered in the differential diagnosis of extramucosal rectal masses in premenopausal women, particularly if the patient has gynecological complaints or a history of infertility.

Combustion-generated nanoparticulates in the El Paso, TX, USA / Juarez, Mexico Metroplex: their comparative characterization and potential for adverse health effects.

In this paper we report on the collection of fine (PM1) and ultrafine (PM0.1), or nanoparticulate, carbonaceous materials using thermophoretic precipitation onto silicon monoxide/formvar-coated 3 mm grids which were examined in the transmission electron microscope (TEM). We characterize and compare diesel particulate matter (DPM), tire particulate matter (TPM), wood burning particulate matter, and other soot (or black carbons (BC)) along with carbon nanotube and related fullerene nanoparticle aggregates in the outdoor air, as well as carbon nanotube aggregates in the indoor air; and with reference to specific gas combustion sources. These TEM investigations include detailed microstructural and microdiffraction observations and comparisons as they relate to the aggregate morphologies as well as their component (primary) nanoparticles. We have also conducted both clinical surveys regarding asthma incidence and the use of gas cooking stoves as well as random surveys by zip code throughout the city of El Paso. In addition, we report on short term (2 day) and longer term (2 week) in vitro assays for black carbon and a commercial multiwall carbon nanotube aggregate sample using a murine macrophage cell line, which demonstrate significant cytotoxicity; comparable to a chrysotile asbestos nanoparticulate reference. The multi-wall carbon nanotube aggregate material is identical to those collected in the indoor and outdoor air, and may serve as a surrogate. Taken together with the plethora of toxic responses reported for DPM, these findings prompt concerns for airborne carbonaceous nanoparticulates in general. The implications of these preliminary findings and their potential health effects, as well as directions for related studies addressing these complex issues, will also be examined.

Cytotoxicity assessment of some carbon nanotubes and related carbon nanoparticle aggregates and the implications for anthropogenic carbon nanotube aggregates in the environment.

Nanotechnology and nanomaterials have become the new frontier world-wide over the past few years and prospects for the production and novel uses of large quantities of carbon nanotubes in particular are becoming an increasing reality. Correspondingly, the potential health risks for these and other nanoparticulate materials have been of considerable concern. Toxicological studies, while sparse, have been concerned with virtually uncharacterized, single wall carbon nanotubes, and the conclusions have been conflicting and uncertain. In this research we performed viability assays on a murine lung macrophage cell line to assess the comparative cytotoxicity of commercial, single wall carbon nanotubes (ropes) and two different multiwall carbon nanotube samples; utilizing chrysotile asbestos nanotubes and black carbon nanoaggregates as toxicity standards. These nanotube materials were completely characterized by transmission electron microscopy and observed to be aggregates ranging from 1 to 2 microm in mean diameter, with closed ends. The cytotoxicity data indicated a strong concentration relationship and toxicity for all the carbon nanotube materials relative to the asbestos nanotubes and black carbon. A commercial multiwall carbon nanotube aggregate exhibiting this significant cell response was observed to be identical in structure to multiwall carbon nanotube aggregates demonstrated to be ubiquitous in the environment, and especially in indoor environments, where natural gas or propane cooking stoves exist. Correspondingly, preliminary epidemiological data, although sparse, indicate a correlation between asthma incidence or classification, and exposure to gas stoves. These results suggest a number of novel epidemiological and etiological avenues for asthma triggers and related respiratory or other environmental health effects, especially since indoor number concentrations for multiwall carbon nanotube aggregates is at least 10 times the outdoor concentration, and virtually all gas combustion processes are variously effective sources. These results also raise concerns for manufactured carbon nanotube aggregates, and related fullerene nanoparticles.

The natural history of mountain cedar pollinosis.

During the winter months, pollen from the mountain cedar (MC) (Juniperus sabinoides) causes severe respiratory tract allergy in central Texas. We have been impressed with the fact that many of our MC-allergic patients had only allergic rhinitis and were only sensitive to MC pollen. We therefore studied 234 unselected MC-allergic patients at the end of the MC season. The main criteria for inclusion into the study was a bona fide history of MC pollinosis confirmed by a positive skin test. All patients completed a detailed history questionnaire, were prick skin tested by using 1:20 w/v, extracts, and had a total IgE determined with commercially available reagents (PRIST). Thirty-four percent of patients were found to be allergic only to MC and 66% were allergic to MC and other aeroallergens. As a group, patients allergic only to MC had significantly lower total IgE levels (84 IU/ml vs. 360, p < 0.001) (normal < 180), required much longer exposure intervals to cedar pollen before developing MC pollinosis (14.4 yr vs, 5.69, p < 0.001), had less of a family history of allergic disease (43% vs. 88%, p < 0.001), had less of a history of asthma or eczema (11% vs. 39%, p < 0.001), and developed allergic disease at a later age (39 yr vs. 13, p < 0.001) when compared to patients with multiple allergies. These results suggest that the MC pollen may be unique in causing allergic rhinitis in patients who have no other sensitivities. A possible explanation may lie in the carbohydrate nature of the main allergen of the MC pollen, which may facilitate allergen transport through the respiratory tract mucosa and subsequent sensitization.

Over-expression of Bcl-2 protects against apoptosis induced by the bioreductive cytotoxic drug SR4233 (Tirapazamine).

The human B-cell lymphoma cell line PW undergoes radiation-induced programmed cell death (PCD). Bcl-2 transfected PW cells, that overexpressed Bcl-2, were significantly more radioresistant than parental or neomycin control transfected PW cells. The viability of Bcl-2 transfected cells was significantly greater than that of parental PW cells treated with the bioreductive cytotoxin SR4233 under aerobic conditions. Bcl-2 transfectants were also significantly more resistant to hypoxia-induced PCD. However, there was no significant difference in the viability of parental and Bcl-2 transfected cells exposed to SR4233 under hypoxic conditions (pO(2)<100 ppm). Incubation of parental PW cells with N-acetyl cysteine decreased the cytotoxicity of SR4233 under aerobic but not anaerobic conditions. Depletion of cellular glutathione with buthionine sulphoxamine killed nearly 100% of control PW cells, but none of the Bcl-2 transfectants under the same conditions. The TBARS assay for lipid peroxidation showed that Bcl-2 transfectants had a significantly lower level of lipid peroxidation than parental PW cells following a 24 hour constant exposure to SR4233 under aerobic conditions. These results suggest that Bcl-2 overexpression inhibits PCD induced by the bioreductive cytotoxin SR4233 under aerobic conditions as well as PCD induced by hypoxia, and that there are other pathways leading to PCD that are unaffected by Bcl-2 overexpression.

Anaphylaxis to annatto dye: a case report.

Annatto dye is an orange-yellow food coloring extracted from the seeds of the tree Bixa orellana. It is commonly used in cheeses, snack foods, beverages, and cereals. Previously reported adverse reactions associated with annatto dye have included urticaria and angioedema. We present a patient who developed urticaria, angioedema, and severe hypotension within 20 minutes following ingestion of milk and Fiber One cereal, which contained annatto dye. Subsequent skin tests to milk, wheat, and corn were negative. The patient had a strong positive skin test to annatto dye, while controls had no response. The nondialyzable fraction of annatto dye on SDS-PAGE demonstrated two protein staining bands in the range of 50 kD. Immunoblotting demonstrated patient IgE-specific for one of these bands, while controls showed no binding. Annatto dye may contain contaminating or residual seed proteins to which our patient developed IgE hypersensitivity. Annatto dye is a potential rare cause of anaphylaxis.

The natural history of mountain cedar pollinosis.

During the winter months, pollen from the mountain cedar (MC) (Juniperus sabinoides) causes severe respiratory tract allergy in central Texas. We have been impressed with the fact that many of our MC-allergic patients had only allergic rhinitis and were only sensitive to MC pollen. We therefore studied 234 unselected MC-allergic patients at the end of the MC season. The main criteria for inclusion into the study was a bona fide history of MC pollinosis confirmed by a positive skin test. All patients completed a detailed history questionnaire, were prick skin tested by using 1:20 w/v, extracts, and had a total IgE determined with commercially available reagents (PRIST). Thirty-four percent of patients were found to be allergic only to MC and 66% were allergic to MC and other aeroallergens. As a group, patients allergic only to MC had significantly lower total IgE levels (84 IU/ml vs. 360, p less than 0.001) (normal less than 180), required much longer exposure intervals to cedar pollen before developing MC pollinosis (14.4 yr vs. 5.69, p less than 0.001), had less of a family history of allergic disease (43% vs. 88%, p less than 0.001), had less of a history of asthma or eczema (11% vs. 39%, p less than 0.001), and developed allergic disease at a later age (39 yr vs. 13, p less than 0.001) when compared to patients with multiple allergies. These results suggest that the MC pollen may be unique in causing allergic rhinitis in patients who have no other sensitivities. A possible explanation may lie in the carbohydrate nature of the main allergen of the MC pollen, which may facilitate allergen transport through the respiratory tract mucosa and subsequent sensitization.

Adverse reactions to venom immunotherapy.

The authors treated 22 adults patients with histories of systemic hypersensitivity to hymenoptera with venom extracts using a traditional approach to immunotherapy. Patients had an immunological response consisting of an increase in venom specific IgE and IgG. Twelve patients underwent an uneventful in-hospital insect sting challenge. Injections of venom extract elicited large reactions in 50% of the patients for which subsequent venom dosages were adjusted proportionately to the local reaction. Using this approach, the investigators observed no systemic reactions to venom therapy. They conclude that systemic reactions to venom immunotherapy may be lessened by the adjustment of venom dose after local reactions to therapy without a loss of efficacy.

The diagnosis of hymenoptera hypersensitivity.

Venom skin testing was performed in 216 patients with histories of systemic or local reactions following insect stings. Seventy-six percent of the patients with histories of systemic reactions and 77% of the patients with histories of local reactions had positive skin tests up to 1 mcg/ml. The majority of vespid sensitive patients had positive skin tests to all the vespid species. Significant (p less than .001) cross-reactivity is suggested by regression analysis. This study confirms the value and safety of venom skin testing in hymenoptera hypersensitivity. The implications for venom immunotherapy of the findings are also discussed.

Immunotherapy in atopic disorders.

Immunotherapy plays an important role in the treatment of allergic rhinitis, asthma, and insect sting allergy. In the latter circumstance, immunotherapy with specific venom from the stinging insects can be life saving. Most commonly employed in immunotherapy are aqueuos extracts of aeroallergens, particularly plant pollen, and mold spores. Recent advances suggest that modification of these allergens, such as polymerization, can result in improved symptom response with fewer side effects. Efficacy trials of immunotherapy have demonstrated satisfactory treatment responses in allergic rhinitis and allergen-induced asthma. These responses, as measured by changes in symptom scores, are attended by specific immunologic changes summarized in Table 2.