Near-Unity Photoluminescence Quantum Yield of Core-Only InP Quantum Dots via a Simple Postsynthetic InF3 Treatment

Indium phosphide (InP) quantum dots (QDs) are considered the most promising alternative for Cd and Pb-based QDs for lighting and display applications. However, while core-only QDs of CdSe and CdTe have been prepared with near-unity photoluminescence quantum yield (PLQY), this is not yet achieved for InP QDs. Treatments with HF have been used to boost the PLQY of InP core-only QDs up to 85%. However, HF etches the QDs, causing loss of material and broadening of the optical features. Here, we present a simple postsynthesis HF-free treatment that is based on passivating the surface of the InP QDs with InF3. For optimized conditions, this results in a PLQY as high as 93% and nearly monoexponential photoluminescence decay. Etching of the particle surface is entirely avoided if the treatment is performed under stringent acid-free conditions. We show that this treatment is applicable to InP QDs with various sizes and InP QDs obtained via different synthesis routes. The optical properties of the resulting core-only InP QDs are on par with InP/ZnSe/ZnS core-shell QDs, with significantly higher absorption coefficients in the blue, and with potential for faster charge transport. These are important advantages when considering InP QDs for use in micro-LEDs or photodetectors.

Size-Dependent Optical Properties of InP Colloidal Quantum Dots

Indium phosphide colloidal quantum dots (CQDs) are the main alternative for toxic and restricted Cd based CQDs for lighting and display applications. Here we systematically report on the size-dependent optical absorption, ensemble, and single particle photoluminescence (PL) and biexciton lifetimes of core-only InP CQDs. This systematic study is enabled by improvements in the synthesis of InP CQDs to yield a broad size series of monodisperse core-only InP CQDs with narrow absorption and PL line width and significant PL quantum yield.

A Water-Free In Situ HF Treatment for Ultrabright InP Quantum Dots

Indium phosphide quantum dots are the main alternative for toxic and restricted Cd-based quantum dots for lighting and display applications, but in the absence of protecting ZnSe and/or ZnS shells, InP quantum dots suffer from low photoluminescence quantum yields. Traditionally, HF treatments have been used to improve the quantum yield of InP to ∼50%, but these treatments are dangerous and not well understood. Here, we develop a postsynthetic treatment that forms HF in situ from benzoyl fluoride, which can be used to strongly increase the quantum yield of InP core-only quantum dots. This treatment is water-free and can be performed safely. Simultaneous addition of the z-type ligand ZnCl₂ increases the photoluminescence quantum yield up to 85%. Structural analysis via XPS as well as solid state and solution NMR measurements shows that the in situ generated HF leads to a surface passivation by indium fluoride z-type ligands and removes polyphosphates, but not PO₃ and PO₄ species from the InP surface. With DFT calculations it is shown that InP QDs can be trap-free even when PO₃ and PO₄ species are present on the surface. These results show that both polyphosphate removal and z-type passivation are necessary to obtain high quantum yields in InP core-only quantum dots. They further show that core-only InP QDs can achieve photoluminescence quantum yields rivalling those of InP/ZnSe/ZnS core/shell/shell QDs and the best core-only II-VI QDs.

Limits of Defect Tolerance in Perovskite Nanocrystals: Effect of Local Electrostatic Potential on Trap States

One of the most promising properties of lead halide perovskite nanocrystals (NCs) is their defect tolerance. It is often argued that, due to the electronic structure of the conduction and valence bands, undercoordinated ions can only form localized levels inside or close to the band edges (i.e., shallow traps). However, multiple studies have shown that dangling bonds on surface Br^– can still create deep trap states. Here, we argue that the traditional picture of defect tolerance is incomplete and that deep Br^– traps can be explained by considering the local environment of the trap states. Using density functional theory calculations, we show that surface Br^– sites experience a destabilizing local electrostatic potential that pushes their dangling orbitals into the bandgap. These deep trap states can be electrostatically passivated through the addition of ions that stabilize the dangling orbitals via ionic interactions without covalently binding to the NC surface. These results shed light on the formation of deep traps in perovskite NCs and provide strategies to remove them from the bandgap.

Cardiovascular disease in an intensive care unit: patterns of an often fatal omen

Background

Care for the critically ill patient with Cardiovascular Disease (CVD) requires a unique management approach, as the theoretical critical threshold for decompensation is lower and inherent adaptive mechanisms may be compromised. We aimed to characterize the prognostic impact of CVD in patients admitted to an Intensive Care Unit (ICU).

Methods

We performed a cohort study of consecutive patients admitted to an ICU from January to December 2019. Patients were stratified as follows: (1) established CVD – presence of either atrial fibrillation, heart failure, coronary artery disease and/or peripheral artery disease; (2) at higher risk of CVD – known arterial hypertension, dyslipidemia, diabetes mellitus and/or current smoking, in the absence of established CVD; and (3) at lower risk of CVD – i.e. none of the above. The co-primary endpoints were all-cause death in ICU and death during index hospitalization.

Results

During 2019, there were 334 admissions in ICU, comprising a total of 296 patients (mean age 67±15 years, 58.1% male). Overall, 69 (23.3%) and 108 (36.5%) died in ICU and during index hospitalization, respectively. Compared to patients at lower risk of CVD, those at higher CVD risk or with established CVD had markers of more severe disease, as noted by higher risk scores (e.g., SAPS-II 35.0±20.0 vs. 43.5±22.3 vs. 52.6±20.0; p<0.001), higher rates of mechanical ventilation (41.5 vs. 57.3 vs. 63.9%; p=0.020), shock during ICU stay (34.0 vs. 52.7 vs. 66.9%; p<0.001) and acute kidney injury (26.4 vs. 35.5 vs. 57.9%; p<0.001), respectively, as well as higher death rates in ICU (5.7 vs. 21.8 vs. 31.6%; p=0.001) and index hospitalization (9.4 vs. 37.3 vs. 46.6%; p<0.001). In multivariate analysis, adjusted for age and cause of admission, established CVD independently predicted the risk of all-cause death in ICU (HR: 2.084; 95% CI: 1.136–3.823; p=0.018) and during index hospitalization (HR 1.712; CI: 1.009–2.889; p=0.046). The analysis for the group of patients at higher risk of CVD yielded similar results to the abovementioned.

Conclusion

Roughly 4 in every 5 patients admitted in ICU were at risk of or had established CVD. The presence of either of the above independently predicted a two- to three-fold higher risk of death during hospitalization. Our findings emphasize the considerable burden of CVD in ICU and underscore the importance of comprehensive management of the complex critically ill patient.

Funding Acknowledgement

Type of funding sources: None.

Cs3Cu4In2Cl13 Nanocrystals: A Perovskite-Related Structure with Inorganic Clusters at A Sites

An effort to synthesize the Cu(I) variant of a lead-free double perovskite isostructural with Cs₂AgInCl₆ resulted in the formation of Cs₃Cu₄In₂Cl₁₃ nanocrystals with an unusual structure, as revealed by single-nanocrystal three-dimensional electron diffraction. These nanocrystals adopt a A₂BX₆ structure (K₂PtCl₆ type, termed vacancy ordered perovskite) with tetrahedrally coordinated Cu(I) ions. In the structure, 25% of the A sites are occupied by [Cu₄Cl]³⁺ clusters (75% by Cs⁺), and the B sites are occupied by In³⁺. Such a Cs₃Cu₄In₂Cl₁₃ compound prepared at the nanoscale is not known in the bulk and is an example of a multinary metal halide with inorganic cluster cations residing in A sites. The stability of the compound was supported by density functional theory calculations that also revealed that its bandgap is direct but parity forbidden. The existence of the Cs₃Cu₄In₂Cl₁₃ structure demonstrates that small inorganic cluster cations can occupy A sites in multinary metal halides.

We report the synthesis of Cs₃Cu₄In₂Cl₁₃ nanocrystals with a vacancy ordered A₂BX₆ perovskite structure, in which Cu(I) ions are tetrahedrally coordinated. In this new structure (determined by single-nanocrystal three-dimensional electron diffraction), 25% of the A sites are occupied by [Cu₄Cl]³⁺ clusters (75% by Cs⁺), while the B sites are occupied by In³⁺. Such a compound, not known in the bulk, is the first case of a perovskite-related structure with inorganic cluster cations residing in A sites.

CsPbX3/SiOx (X = Cl, Br, I) monoliths prepared via a novel sol-gel route starting from Cs4PbX6 nanocrystals

We developed a facile synthesis of nanocomposite powders of CsPbX₃ nanocrystals (NCs) embedded in silica. The synthesis starts from colloidal Cs₄PbX₆ NCs that are mixed with tetraethyl orthosilicate in the presence of nitric acid, which triggers the sol-gel reaction yielding the formation of SiO_x and the conversion of starting NCs into CsPbX₃ ones. The overall reaction delivers CsPbX₃ NCs encased in a silica matrix. The resulting CsPbX₃/SiO_x nano-composite powders exhibited enhanced moisture and thermal stability in air. Also, when mixing different CsPbX₃/SiO_x samples having diverse anion compositions, no interparticle anion exchange processes were observed, which is a further indication that the silica matrix acts as a robust barrier surrounding the NCs. Finallly, we used these composites as down-converter phosphors on top of a blue light-emitting diode (LED), delivering nearly ideal white light emission with the Commission Internationale de l'Eclairage (CIE) color coordinates (0.32, 0.33).

Nitinol versus non-Nitinol prostheses in otosclerosis surgery: a meta-analysis

The aim of this study is to perform a systematic review and meta-analysis of observational studies in which hearing outcomes after primary stapes surgery have been reported. After the surgical procedure, the effectiveness of stapes surgery using nickel titanium (Nitinol) or other prostheses were systematically compared and evaluated using a meta-analytic method. A systematic search for articles before January 2017 in Embase, Medline and Cochrane Library databases was conducted. Only articles in English were included. Inclusion criteria for qualitative synthesis consisted of a population of otosclerosis patients, intervention with primary stapes surgery using the Nitinol heat-crimping prosthesis compared with other type of stapes stapedotomy prostheses, and hearing outcome. Inclusion criteria for quantitative analysis consisted of application of audiometry guidelines of the American Academy of Otolaryngology Head and Neck Surgery Committee on Hearing and Equilibrium for evaluation of conductive hearing loss. A postoperative air-bone gap (ABG) ≤ 10 dB was considered effective. A bias assessment tool was developed according to Cochrane guidelines. To evaluate the mean age of the samples we used the chi-square test. Of the 4926 papers identified through the electronic database search (3695 in Pubmed/Cochrane and 1231 in Embase), 540 studies matched the selection criteria (436 in Pubmed/Cochrane and 104 in Embase) after application of filters and elimination of duplicate articles. After analysis of the title and abstract, 459 were excluded (396 in Pubmed/Cochrane and 63 in Embase). Of the remaining 81 papers, 74 were excluded according to the study selection criteria. A total of seven eligible studies with 1385 subjects, consisting of 637 in the Nitinol group and 748 in the non-Nitinol group, were included in our study. There were statistically significant differences in the effectiveness of stapes surgery between the Nitinol and non-Nitinol prostheses; the data showed a combined odds ratio (OR) of 2.56 (95% CI 1.38-4.76, p = 0.003). There were no statistically significant differences in the mean pre-operative age between Nitinol and non-Nitinol prostheses (p = 0.931). Our results suggest that the effectiveness of Nitinol was higher than non-Nitinol prostheses, with superiority of the number of patients with ABG ≤ 10 dB.

The Phosphine Oxide Route toward Lead Halide Perovskite Nanocrystals

We report an amine-free synthesis of lead halide perovskite (LHP) nanocrystals, using trioctylphosphine oxide (TOPO) instead of aliphatic amines, in combination with a protic acid (e.g., oleic acid). The overall synthesis scheme bears many similarities to the chemistry behind the preparation of LHP thin films and single crystals, in terms of ligand coordination to the chemical precursors. The acidity of the environment and hence the extent of protonation of the TOPO molecules tune the reactivity of the PbX2 precursor, regulating the size of the nanocrystals. On the other hand, TOPO molecules are virtually absent from the surface of our nanocrystals, which are simply passivated by one type of ligand (e.g., Cs-oleate). Furthermore, our studies reveal that Cs-oleate is dynamically bound to the surface of the nanocrystals and that an optimal surface coverage is critical for achieving high photoluminescence quantum yield. Our scheme delivers NCs with a controlled size and shape: only cubes are formed, with no contamination with platelets, regardless of the reaction conditions that were tested. We attribute such a shape homogeneity to the absence of primary aliphatic amines in our reaction environment, since these are known to promote the formation of nanocrystals with sheet/platelet morphologies or layered phases under certain reaction conditions. The TOPO route is particularly appealing with regard to synthesizing LHP nanocrystals for large-scale manufacturing, as the yield in terms of material produced is close to the theoretical limit: i.e., almost all precursors employed in the synthesis are converted into nanocrystals.

Role of Acid-Base Equilibria in the Size, Shape, and Phase Control of Cesium Lead Bromide Nanocrystals

A binary ligand system composed of aliphatic carboxylic acids and primary amines of various chain lengths is commonly employed in diverse synthesis methods for CsPbBr₃ nanocrystals (NCs). In this work, we have carried out a systematic study examining how the concentration of ligands (oleylamine and oleic acid) and the resulting acidity (or basicity) affects the hot-injection synthesis of CsPbBr₃ NCs. We devise a general synthesis scheme for cesium lead bromide NCs which allows control over size, size distribution, shape, and phase (CsPbBr₃ or Cs₄PbBr₆) by combining key insights on the acid-base interactions that rule this ligand system. Furthermore, our findings shed light upon the solubility of PbBr₂ in this binary ligand system, and plausible mechanisms are suggested in order to understand the ligand-mediated phase control and structural stability of CsPbBr₃ NCs.

Efficiency of compensatory orthodontic treatment of mild Class III malocclusion with two different bracket systems

Objective:

The purpose of this study was to assess the efficiency of compensatory orthodontic treatment of patients with mild Class III malocclusion with two preadjusted bracket systems.

Method:

Fifty-six matched patients consecutively treated for mild Class III malocclusion through compensatory dentoalveolar movements were retrospectively evaluated after analysis of orthodontic records. The sample was divided into two groups according to the brackets used: Group 1 = non-Class III compensated preadjusted brackets, Roth prescription (n = 28); Group 2 = compensated Class III preadjusted brackets, Capelozza III prescription (n = 28). Cephalometric analysis, number of appointments and missed appointments, months using Class III elastics, and bond/band failures were considered. Treatment time, Peer Assessment Rating (PAR) index at the beginning (PAR T₁) and end of treatment (PAR T₂) were used to calculate treatment efficiency. Comparison was performed using a MANOVA at p< 0.05.

Results:

Missed appointments, bond or band failures, number of months using the Class III intermaxillary elastics, and cephalometric measurements showed no statistically significant difference (p> 0.05) between groups. Patients treated with Roth brackets had a treatment time 7 months longer (p= 0.01). Significant improvement in the patient’s occlusion (PAR T₂-T₁) was observed for both groups without difference (p= 0.22).

Conclusions:

Orthodontic brackets designed for compensation of mild Class III malocclusions appear to be more efficient than non-compensated straight-wire prescription brackets. Treatment time for Class III patients treated with brackets designed for compensation was shorter than with Roth prescription and no difference in the quality of the occlusal outcome was observed. A prospective randomized study is suggested to provide a deeper look into this subject.

Colloidal Monolayer β-In2Se3 Nanosheets with High Photoresponsivity

We report a low-temperature colloidal synthesis of single-layer, five-atom-thick, β-In₂Se₃ nanosheets with lateral sizes tunable from ∼300 to ∼900 nm, using short aminonitriles (dicyandiamide or cyanamide) as shape controlling agents. The phase and the monolayer nature of the nanosheets were ascertained by analyzing the intensity ratio between two diffraction peaks from two-dimensional slabs of the various phases, determined by diffraction simulations. These findings were further backed-up by comparing and fitting the experimental X-ray diffraction pattern with Debye formula simulated patterns and with side-view high-resolution transmission electron microscopy imaging and simulation. The β-In₂Se₃ nanosheets were found to be indirect band gap semiconductors (E_g = 1.55 eV), and single nanosheet photodetectors demonstrated high photoresponsivity and fast response times.

Colloidal CuFeS2 Nanocrystals: Intermediate Fe d-Band Leads to High Photothermal Conversion Efficiency

We describe the colloidal hot-injection synthesis of phase-pure nanocrystals (NCs) of a highly abundant mineral, chalcopyrite (CuFeS2). Absorption bands centered at around 480 and 950 nm, spanning almost the entire visible and near-infrared regions, encompass their optical extinction characteristics. These peaks are ascribable to electronic transitions from the valence band (VB) to the empty intermediate band (IB), located in the fundamental gap and mainly composed of Fe 3d orbitals. Laser-irradiation (at 808 nm) of an aqueous suspension of CuFeS2 NCs exhibited significant heating, with a photothermal conversion efficiency of 49%. Such efficient heating is ascribable to the carrier relaxation within the broad IB band (owing to the indirect VB-IB gap), as corroborated by transient absorption measurements. The intense absorption and high photothermal transduction efficiency (PTE) of these NCs in the so-called biological window (650-900 nm) make them suitable for photothermal therapy as demonstrated by tumor cell annihilation upon laser irradiation. The otherwise harmless nature of these NCs in dark conditions was confirmed by in vitro toxicity tests on two different cell lines. The presence of the deep Fe levels constituting the IB is the origin of such enhanced PTE, which can be used to design other high performing NC photothermal agents.

Persistent and non-persistent strains of Listeria monocytogenes: A focus on growth kinetics under different temperature, salt, and pH conditions and their sensitivity to sanitizers

This study aimed to investigate the effect of different conditions, including temperature (37 °C, 22 °C, and 4 °C), NaCl concentrations (2.5%, 4%, and 8%), and acidity (pH = 5), on the growth response of persistent and non-persistent isolates of Listeria monocytogenes. The resistance to two common sanitizers (benzalkonium chloride and hydrogen peroxide) was also investigated. A selected group of 41 persistent and non-persistent L. monocytogenes isolates recovered from three cheese processing plants during a previous longitudinal study was assembled. Average lag time was similar for persistent and non-persistent isolates grown at 37 °C, 22 °C and 4 °C but significantly shorter (p < 0.05) for persistent isolates grown at 2.5%, 4% and 8% NaCl, and at pH 5. Average growth rates were significantly higher (p < 0.05) for persistent than for non-persistent isolates when grown at 22 °C, 2.5%, 4% and 8% NaCl, and at pH 5. These results suggest that persistent strains may be better adapted to grow under stressful conditions frequently encountered in food processing environments than non-persistent strains. No relation between persistence and resistance to the tested sanitizers was found.

The association of HPV genotype with the regression, persistence or progression of low-grade squamous intraepithelial lesions

BACKGROUND

Human papillomavirus (HPV) is a highly prevalent sexually transmitted virus causing cytological alterations that precede cervical cancer. Approximately 130 genotypes have been sequenced. Low-grade squamous intraepithelial lesions (LSIL) are the most frequent cytological alteration and have an uncertain behavior.

OBJECTIVES

To analyze the frequency of HPV types in LSIL and their association with the regression, persistence or progression of these lesions.

METHODS

A cohort study of forty patients with LSIL cytology was conducted from December 2007 to March 2011. The follow-up lasted two years and included cytology and colposcopy. HPV detection was performed using PCR, and genotyping was performed using PCR-specific and RFLP techniques.

RESULTS

DNA-HPV was detected in 87% (35/40) of the cases, with oncogenic HPV accounting for 76%; type 16 in 32% (11/35) and type 18 in 20%. LSIL regression, persistence and progression rates at the end of the study were 60%, 23% and 17%, respectively. There was 50% regression in lesions in the high oncogenic risk group (types 16 and 18).

CONCLUSION

HPV 16 was the most frequent genotype found in LSIL. The persistence and progression of the LSIL were related to the persistence of oncogenic HPV. The longer the follow-up time, the lower the LSIL persistence rate and the higher its regression rate; the progression rate remained stable. In addition to the presence of oncogenic HPV, other factors are necessary for the progression of LSIL.

Cheese-related listeriosis outbreak, Portugal, March 2009 to February 2012

In Portugal, listeriosis has been notifiable since April 2014, but there is no active surveillance programme for the disease. A retrospective study involving 25 national hospitals led to the detection of an outbreak that occurred between March 2009 and February 2012. The amount of time between the start of the outbreak and its detection was 16 months. Of the 30 cases of listeriosis reported, 27 were in the Lisbon and Vale do Tejo region. Two cases were maternal/neonatal infections and one resulted in fetal loss. The mean age of the non-maternal/neonatal cases was 59 years (standard deviation: 17); 13 cases were more than 65 years old. The case fatality rate was 36.7%. All cases were caused by molecular serogroup IVb isolates indistinguishable by pulsed-field gel electrophoresis and ribotype profiles. Collaborative investigations with the national health and food safety authorities identified cheese as the probable source of infection, traced to a processing plant. The magnitude of this outbreak, the first reported food-borne listeriosis outbreak in Portugal, highlights the importance of having an effective listeriosis surveillance system in place for early detection and resolution of outbreaks, as well as the need for a process for the prompt submission of Listeria monocytogenes isolates for routine laboratory typing.

Foci of contamination of Listeria monocytogenes in different cheese processing plants

Listeria monocytogenes is a ubiquitous bacterium widely distributed in the environment that can cause a severe disease in humans when contaminated foods are ingested. Cheese has been implicated in sporadic cases and in outbreaks of listeriosis worldwide. Environmental contamination, in several occasions by persistent strains, has been considered an important source of finished product contamination. The objectives of this research were to (i) evaluate the presence of L. monocytogenes within the factory environments and cheeses of three processing plants, artisanal producer of raw ewe's milk cheeses (APC), small-scale industrial cheese producer (SSI) and industrial cheese producer (ICP) each producing a distinct style of cheese, all with history of contamination by L. monocytogenes (ii) and identify possible sources of contamination using different typing methods (arsenic and cadmium susceptibility, geno-serotyping, PFGE). The presence of markers specific for 3 epidemic clones (ECI-ECIII) of L. monocytogenes was also investigated. Samples were collected from raw milk (n = 179), whey (n = 3), cheese brining solution (n = 7), cheese brine sludge (n = 505), finished product (n = 3016), and environment (n = 2560) during, at least, a four-year period. Listeria monocytogenes was detected in environmental, raw milk and cheese samples, respectively, at 15.4%, 1.1% and 13.6% in APC; at 8.9%, 2.9% and 3.4% in SSI; and at 0%, 21.1% and 0.2% in ICP. Typing of isolates revealed that raw ewe's milk and the dairy plant environment are important sources of contamination, and that some strains persisted for at least four years in the environment. Although cheeses produced in the three plants investigated were never associated with any case or outbreak of listeriosis, some L. monocytogenes belonging to specific PFGE types that caused disease (including putative epidemic clone strains isolated from final products) were found in this study.

'Homens trans': novos matizes na aquarela das masculinidades?

O artigo discute de forma exploratória a emergência de uma nova categoria identitária no Brasil, a de 'homem trans'. Essa se constrói diferenciando-se da identidade lésbica e, também, de expressões de gênero de outros grupos que tiveram seus corpos assignados como femininos ao nascimento, mas que contestam essa assignação sem, contudo, se afirmarem 'homens' de forma constante. Afirma-se que a emergência dos 'homens trans' tem sido potencializada pelo estabelecimento do processo transexualizador no SUS. Discutem-se o uso do termo "homem trans" e algumas características comuns a tais sujeitos. Problematizam-se a complexidade de seus processos de autorreconhecimento e construção de masculinidades, sua rápida capacidade de indiferenciação a partir de modificações corporais e, alguns dos efeitos políticos e subjetivos, da visibilidade e da indiferenciação.

Behaviour of Listeria monocytogenes isolates through gastro-intestinal tract passage simulation, before and after two sub-lethal stresses

The effects of previous exposure to sub-lethal acidic and osmotic stresses on the survival of Listeria monocytogenes during exposure to gastro-intestinal (GI) tract simulation, was investigated. Six L. monocytogenes strains isolated from cheeses were selected and exposed to high salt concentrations or acidic conditions and their viability compared in quick and slow digestions. The results demonstrated that (i) all isolates were more sensitive to the exposure to acidic than to osmotic sub-lethal conditions (ii) significant differences (p < 0.05) between the two types of digestion were observed; in slow digestion, the log reduction was higher for all the tested isolates (iii) all isolates were inhibited in the presence of bile salts for both types of digestion (iv) differences between quick and slow digestion were not observed (p > 0.05) after exposure to either osmotic or acidic stress (v) a higher cellular inactivation (p < 0.001) was observed during the passage through the GI tract simulation after exposure to osmotic than to acidic stresses and (vi) neither osmotic nor acidic sub-lethal stresses conferred resistance to simulated GI tract conditions.

Detection of Salmonella spp. survival and virulence in poultry feed by targeting the hilA gene

AIMS

The objectives of this work were to evaluate immunomagnetic beads and a reverse transcriptase (RT)-PCR method for the detection of Salmonella inoculated into feed. In addition, a reverse transcriptase (RT)-PCR method was evaluated for quantifying virulence gene hilA expression of Salmonella ssp. in poultry feed matrices and utilized to determine the influence of poultry feed environmental factors on Salmonella hilA expression.

METHODS AND RESULTS

An immunomagnetic separation technique was evaluated for increased recovery of Salmonella from feed. Salmonella cultures were inoculated into feed samples and exposed to heat treatments of 70°C and sampled periodically. From these samples, RNA was collected and hilA gene expression was measured relative to the housekeeping 16S rRNA gene. The immunomagnetic bead protocol increased recovery by 1 log. The up-regulation of hilA was demonstrated after 5 and 10 min of inoculated feed samples being exposed to heat treatment.

CONCLUSIONS

From this work, the data indicate that the ability to detect live Salmonella cells in feed samples may be increased by targeting the hilA gene.

SIGNIFICANCE AND IMPACT OF THE STUDY

Foodborne salmonellosis originating from poultry is a major problem, and feed is a leading source of contamination in poultry, but detection in feed is complicated by low concentrations. The assays and experiments in this study examine possible improvements to recovery and detection of Salmonella in feed.

Integrating the implementation of the European Union Water Framework Directive and Floods Directive in Ireland

Water Framework Directive (WFD) statutory authorities and stakeholders in Ireland are now challenged with the issue of how the proposed programmes of measures in the newly required River Basin Management Plans - designed to protect and restore good ecology by reverting as closely as possible back to natural conditions - are to be implemented in a way that concurrently complies with other existing and emerging intersecting European Union legislation, such as the Floods Directive (FD). The WFD is driven largely by ecological considerations, whereas the FD and other legislation are more geared towards protecting physical property and mitigating public safety risks. Thus many of the same waterbodies, especially heavily modified waterbodies, arguably have somewhat competing policy objectives put upon them. This paper explores the means by which Ireland might best achieve the highest degrees of cost effectiveness, economic efficiency and institutional durability in pursuing the common and overarching objective of the WFD and FD - to ensure Irish waterways are put to their highest valued uses.

Alterations in energy properties of eucalyptus wood and bark subjected to torrefaction: the potential of mass loss as a synthetic indicator

Torrefaction is a mild pyrolysis process (usually up to 300 degrees C) that changes the chemical and physical properties of biomass. This process is a possible pre-treatment prior to further processes (transport, grinding, combustion, gasification, etc) to generate energy or biofuels. In this study, three eucalyptus wood species and bark were subjected to different torrefaction conditions to determine the alterations in their structural and energy properties. The most severe treatment (280 degrees C, 5h) causes mass losses of more than 35%, with severe damage to anatomical structure, and an increase of about 27% in the specific energy content. Bark is more sensitive to heat than wood. Energy yields are always higher than mass yields, thereby demonstrating the benefits of torrefaction in concentrating biomass energy. The overall mass loss is proposed as a relevant parameter to synthesize the effect of torrefaction conditions (temperature and duration). Accordingly, all results are summarised by analytical expressions able to predict the energy properties as a function of the overall mass loss. These expressions are intended to be used in any optimization procedure, from production in the field to the final use.

Distribution and characterization of Listeria monocytogenes clinical isolates in Portugal, 1994-2007

In recent years, the number of cases of listeriosis has increased worldwide. Ninety-five isolates of Listeria monocytogenes recovered from Portuguese human cases of listeriosis have been characterized by biotyping (cadmium and arsenic sensitivity), polymerase chain reaction (PCR) grouping, and by pulsed-field gel electrophoresis (PFGE) applying the enzymes AscI and ApaI. Isolates were classified into one of three PCR groups; IVb (71.6%), IIb (17.9%), and IIa (10.5%). Four biotypes were differentiated: sensitive to arsenic/cadmium (48.4%), arsenic-sensitive and cadmium-resistant (25.3%), resistant to arsenic and sensitive to cadmium (18.9%), and resistant to both heavy metals (7.4%). Combined analyses of AscI and ApaI patterns yielded a total of 58 PFGE types with five sets (G, Jb, KKa, Me, and U) of Portuguese strains, each of which were indistinguishable by PFGE typing. In the present study, it was demonstrated that there are recurrent pulsotypes and that some were the same pulsotypes linked to outbreaks in France. In addition, there are some pulsotypes spread throughout the country, while others only appear in a restricted region. This study allowed the assembly of a first large pulsotype database of Portuguese clinical strains.

Chemical composition changes in eucalyptus and pinus woods submitted to heat treatment

This study investigated the influence of heat treatment on the chemical composition of Eucalyptus saligna and Pinus caribaea var. hondurensis woods to understand its role in wood processing. E. saligna and P. caribaea var. hondurensis woods were treated in a laboratorial electric furnace at 120, 140, 160 and 180 degrees C to induce their heat treatment. The chemical composition of the resulting products and those from original wood were determined by gas chromatography. Eucalyptus and Pinus showed a significant reduction in arabinose, manose, galactose and xylose contents when submitted to increasing temperatures. No significant alteration in glucose content was observed. Lignin content, however, increased during the heat process. There was a significant reduction in extractive content for Eucalyptus. On the other hand, a slight increase in extractive content has been determined for the Pinus wood, and that only for the highest temperature. These different behaviors can be explained by differences in chemical constituents between softwoods and hardwoods. The results obtained in this study provide important information for future research and utilization of thermally modified wood.

Analysis of human papillomavirus and Epstein-Barr virus infection and aberrant death-associated protein kinase methylation in high-grade squamous intraepithelial lesions

This study was conducted to investigate the presence of Epstein-Barr virus (EBV) and human papillomavirus (HPV) and the promoter methylation status of the death-associated protein kinase (DAPK) gene in high-grade intraepithelial lesions. Viral infection was analyzed using polymerase chain reaction (PCR), and promoter methylation status was evaluated using chemical modification by sodium bisulfite followed by PCR. A total of 24 samples were studied. HPV was detected in 16.6%, EBV in 16.6%, and HPV/EBV coinfection in 16.6%. No virus infection was detected in 50% of the samples studied. DAPK promoter methylation was observed in 29.2% of the analyzed samples. There was no significant correlation between DAPK methylation and viral infection. DAPK methylation was detected in 28% of HPV-positive lesions, in 28% of HPV- and EBV-positive lesions, and in 44% (3/7) of the samples without viral infection. There was no observed methylation in samples with isolated EBV infection. In DAPK unmethylated samples, HPV infection was found in 12%, EBV infection in 23%, HPV/EBV coinfection in 12%, and an absence of HPV and EBV infection in 53%. The promoter methylation of the DAPK gene is an important event during carcinogenesis and may have potential clinical application as a marker for the progression and prognosis of cancer.

Crystallization and preliminary X-ray analysis of a membrane-bound nitrite reductase from Desulfovibrio desulfuricans ATCC 27774

Nitrite reductase from the sulfate-reducing bacterium Desulfovibrio desulfuricans ATCC 27774 is a multihaem (type c) membrane-bound enzyme that catalyzes the dissimilatory conversion of nitrite to ammonia. Crystals of the oxidized form of this enzyme were obtained using PEG and CaCl(2) as precipitants in the presence of 3--(decylmethylammonium)propane-1-sulfonate and belong to the space group P2(1)2(1)2(1), with unit-cell parameters a = 78.94, b = 104.59, c = 143.18 A. A complete data set to 2.30 A resolution was collected using synchrotron radiation at the ESRF. However, the crystals may diffract to beyond 1.7 A and high-resolution data will be collected in the near future.

[Primary hyperaldosteronism--12 clinical cases]

STUDY OBJECTIVES

To show clinical, biochemical, and morphological data of 12 patients with primary hyperaldosteronism: eight with an aldosterone-producing adenoma and four with adrenal hyperplasia. To compare clinical and biochemical parameters of the patients with adenoma and hyperplasia. For those with adenoma, to verify clinical and biochemical modifications after adrenalectomy.

PATIENTS AND METHODS

In the 12 patients with hyperaldosteronism, retrospective analysis of clinical (age, sex, blood pressure), biochemical (plasmatic and urinary potassium, plasmatic aldosterone, plasma renin activity, and plasmatic aldosterone/renin activity ratio), and morphological (computed tomography, magnetic resonance, and norcholesterol scintigraphy) data was performed.

RESULTS

1--In the 12 patients with hyperaldosteronism (seven female), the age was 51.0 +/- 10.2 years (mean +/- standard deviation), the systolic pressure 200.9 +/- 34.5 mm Hg and the diastolic pressure 120.0 +/- 12.3 mm Hg. Hypertension was diagnosed 12.0 +/- 10.1 years before. As biochemical evidence, we found kalaemia of 3.06 +/- 0.28 and urinary potassium of 63.4 +/- 16.5 mEq/l, renin activity 0.98 +/- 1.02 ng/ml/h, plasmatic aldosterone of 49.4 +/- 36.0 ng/dl, aldosterone/renin activity > 30 in 83% of the cases. As morphological evidence, computed tomography allowed diagnosis in nine patients, suggested it in two, being doubtful in one. Performed on four patients, resonance confirmed the tomography in three and was not contributive in one. The scintigraphy performed in four patients visualized two adenomas, was negative in one adenoma and in one hyperplasia. 2--In the eight patients with adenoma (six female), the youngest age and the highest diastolic pressure compared with patients with hyperplasia were statistically significant (p < 0.01 and 0.05). In the adenomas, the biochemical changes were more pronounced, but not statistically significant. The plasmatic aldosterone/renin activity ratio was also higher in the adenoma cases. 3--After the adrenalectomy, blood pressure became normal in five patients and was more easily therapeutically controlled in three. The average systolic and diastolic pressures decreased and the biochemical parameters became normal in all patients. The pre/post surgical modification of these parameters had statistical significance (systolic pressure decrease, p < 0.01; diastolic pressure decrease, p < 0.01; kalaemia increase, p < 0.001; renin activity increase, p < 0.01; aldosterone decrease, p < 0.02). The plasmatic aldosterone/renine activity ratio normalized in all patients.

CONCLUSIONS

In diagnosing primary hyperaldosteronism, biochemical (kalaemia, urinary potassium, plasmatic aldosterone, renin activity, aldosterone plasmatic/renin activity) and tomography studies were important. On comparing the patients with hyperplasia with those with adenoma, we found that the latter are younger and exhibit higher diastolic pressure, both findings with statistical significance. After adenoma surgery, blood pressure became normal in five patients and improved in three, these findings, and the improvement of the kalaemia, plasmatic aldosterone, and renin activity parameters were statistically significant.

The effect of short-chain fatty acids on the susceptibility of human umbilical vein endothelial cells to human cytomegalovirus infection

We have compared the replication of three strains of human cytomegalovirus (HCMV), HCMV AD-169, HCMV Towne, or HCMV RC-256, an insertional mutant of Towne containing the LacZ gene of E. coli, in human umbilical vein endothelial cells (HUVEC) and human forskin fibroblasts (HFF). We also examine the effects of salts of short-chain fatty acids on the susceptibility of HUVEC to infection by HCMV. All three virus strains replicated in both cell types, but 10-to 100-fold less virus was produced in HUVEC cells than HFF. For all virus strains, expression of HCMV IE-1 antigen in HFF was > 70% 24 h after inoculation. In contrast, the number of HUVEC exhibiting IE-1 antigen at 24 h was < 15%. Treatment of HUVEC with sodium butyrate, sodium hexanoate, or sodium propionate prior to virus inoculation increased the IE-1 and late HCMV antigen expression in a dose- and time-dependent manner. Virus yield was also increased. This increased susceptibility was inhibited by cycloheximide and tunicamycin, indicating a requirement for new cellular protein synthesis. Treatment with both sodium hexanoate and propionate after virus inoculation increased HUVEC susceptibility to HCMV infection. Treatment of HUVEC with sodium butyrate after virus inoculation also increased HCMV IE-1 antigen expression, but only after removal of the drug. These studies demonstrate that the susceptibility of HUVEC to HCMV infection can be increased by the treatment of the host cell with salts of short-chain fatty acids, such as sodium butyrate, before or after virus inoculation.

[Endocrine arterial hypertension. Pheochromocytoma]

The authors emphasize some embryologic features of the chromaffin tissue as a basis of understanding of both the physiopathologic and clinical aspects of Pheochromocytoma. The appropriate sequence of diagnostic procedures was established in order to obtain clinical, biochemical and anatomical evidence of the tumor. It was concluded that an early diagnosis is mandatory in order to plan a curative surgical therapeutic approach. The embryologic and biochemical understanding of the Pheochromocytoma, in the context of the neuroendocrine tumors, allows a better rationale both for the diagnosis and therapy of this condition.