Built-in tensile strain dependence on the lateral size of monolayer MoS2 synthesized by liquid precursor chemical vapor deposition.

Strain engineering is an efficient tool to tune and tailor the electrical and optical properties of 2D materials. The built-in strain can be tuned during the synthesis process of a two-dimensional semiconductor, such as molybdenum disulfide, by employing different growth substrates with peculiar thermal properties. In this work, we demonstrate that the built-in strain of MoS2 monolayers, grown on a SiO2/Si substrate by liquid precursor chemical vapor deposition, is mainly dependent on the size of the monolayer. In fact, we identify a critical size equal to 20 µm, from which the built-in strain increases drastically. The built-in strain is the maximum for a 60 µm sized monolayer, leading to 1.2% tensile strain with a partial release of strain close to the monolayer triangular vertexes due to the formation of nanocracks. These findings also imply that the standard method for evaluation of the number of layers based on the Raman mode separation can become unreliable for highly strained monolayers with a lateral size above 20 µm.

Experimental assessment of an indirect method to measure the post-combustion flue gas flow rate in waste-to-energy plant based on multi-point measurements.

In waste-to-energy plants, the determination of the flue gas flow rate in the post-combustion section is of the utmost importance, e.g., for the verification of the compliance to the minimum residence time requirements (tres>2s) or for the control of flue gas treatment reactant injection, but the harsh conditions (high temperature and content of pollutants) do not allow for a direct measurement. The present work reports an experimental assessment of an indirect approach to estimate the flue gas flow rate in the post-combustion section of a rotary kiln plant with reduced uncertainty. This method consists on the direct measurement of the flow rate at a "colder" section of the plant (the boiler outlet) combined to the simultaneous measurements of flue gas composition measurements upstream and downstream of the boiler. From these measurements it is then possible to determine the mass of false air and to retrieve the actual flue gas flow-rate in the post-combustion chamber. A massive experimental campaign has been conducted at a full-scale medical waste incinerator, in which flue gas flow rate was estimated at different waste loads and ambient conditions. The results show that the percentage of false air can be significant and simply neglecting it can lead to substantial under-performance of the plant. Issues related to the practical implementation of the methods are illustrated in detail and the possibility to extend the methodology towards an online determination of post-combustion flue gas flow rate is discussed.

Fluoride doped γ-Fe2O3 nanoparticles with increased MRI relaxivity.

Iron oxide nanoparticles (IONs) are being actively researched and experimented with as contrast agents for Magnetic Resonance Imaging (MRI), as well as image-directed delivery of therapeutics. The efficiency of an MRI contrast agent can be described by its longitudinal and transverse relaxivities, r1 and r2. γ-Fe2O3 nanoparticles - doped with fluoride in a controlled manner and functionalised with citric acid - showed a 3-fold increase in r1 and a 17-fold increase in r2 in a magnetic field of 3 T and almost 6-fold increase in r1 and a 14-fold increase in r2 at 11 T. Following fluorination, PXRD shows that the crystal structure of γ-Fe2O3 is maintained, Mössbauer spectroscopy shows that the oxidation state of the Fe cation is unchanged and HREM shows that the particle size does not vary. However, magnetisation curves show a large increase in the coercive field, pointing towards a large increase in the magnetic anisotropy for the fluorinated nanoparticles compared to the un-doped γ-Fe2O3 nanoparticles. Therefore, a chemically induced increase in magnetic anisotropy appears to be the most relevant parameter responsible for the large increase in relaxivity for γ-Fe2O3 nanoparticles.

Novel near-infrared emission from crystal defects in MoS2 multilayer flakes.

The structural defects in two-dimensional transition metal dichalcogenides, including point defects, dislocations and grain boundaries, are scarcely considered regarding their potential to manipulate the electrical and optical properties of this class of materials, notwithstanding the significant advances already made. Indeed, impurities and vacancies may influence the exciton population, create disorder-induced localization, as well as modify the electrical behaviour of the material. Here we report on the experimental evidence, confirmed by ab initio calculations, that sulfur vacancies give rise to a novel near-infrared emission peak around 0.75 eV in exfoliated MoS2 flakes. In addition, we demonstrate an excess of sulfur vacancies at the flake's edges by means of cathodoluminescence mapping, aberration-corrected transmission electron microscopy imaging and electron energy loss analyses. Moreover, we show that ripplocations, extended line defects peculiar to this material, broaden and redshift the MoS2 indirect bandgap emission.

The optimum cut-off value to differentiate Echinococcus granulosus sensu stricto from other species of E. granulosus sensu lato using larval rostellar hook morphometry.

Cystic echinococcosis caused by Echinococcus granulosus sensu lato is one of the most important helminth zoonoses in the world; it affects both humans and livestock. The disease is endemic in Argentina and highly endemic in the province of Neuquén. Considerable genetic and phenotypic variation has been demonstrated in E. granulosus, and ten different genotypes (G1-G10) have been identified using molecular tools. Echinococcus granulosus sensu lato may be considered a species complex, comprised of E. granulosus sensu stricto (G1-G3), E. equinus (G4), E. ortleppi (G5) and E. canadensis (G6-G10). In endemic areas, the characterization of cystic echinococcosis molecular epidemiology is important in order to apply adequate control strategies. A cut-off value for larval large hook total length to distinguish E. granulosus sensu stricto isolates from those produced by other species of the complex was defined for the first time. Overall, 1780 larval hooks of 36 isolates obtained from sheep (n= 11, G1), goats (n= 10, G6), cattle (n= 5, G6) and pigs (n= 10, G7) were analysed. Validation against molecular genotyping as gold standard was carried out using the receiver operating characteristic (ROC) curve analysis. The optimum cut-off value was defined as 26.5 µm. The proposed method showed high sensitivity (97.8%) and specificity (91.1%). Since in most endemic regions the molecular epidemiology of echinococcosis includes the coexistence of the widely distributed E. granulosus sensu stricto G1 strain and other species of the complex, this technique could be useful as a quick and economical tool for epidemiological and surveillance field studies, when fertile cysts are present.

Selective response inversion to NO2 and acetic acid in ZnO and CdS nanocomposite gas sensor.

High sensitivity zinc oxide (ZnO) tetrapods (TPs) have been functionalized by nucleating cadmium sulphide (CdS) nanoparticles (NPs) directly on their surface with a spotted coverage thanks to an optimized synthesis in dimethylformamide (DMF). The obtained hybrid coupled material has been used to realize a gas sensing device with a highly porous nanostructured network, in which the proper alternation of ZnO-TPs and CdS-NPs gives rise to unconventional chemoresistive behaviours. Among the different tested gases and vapours, the sensor showed a unique fingerprint response-inversion between 300 °C and 400 °C only for nitrogen dioxide (NO2) and acetic acid (CH3COOH).

Composite multifunctional nanostructures based on ZnO tetrapods and superparamagnetic Fe3O4 nanoparticles.

A nanocomposite material is obtained by coupling superparamagnetic magnetite nanoparticles (Fe3O4 NP) and vapor phase grown zinc oxide nanostructures with 'tetrapod' morphology (ZnO TP). The aim is the creation of a multifunctional material which retains the attractive features of ZnO (e.g. surface reactivity, strong UV emission, piezoelectricity) together with added magnetism. Structural, morphological, optical, magnetic and functional characterization are performed. In particular, the high saturation magnetization of Fe3O4 NP (above 50 A m(2) kg(-1)), the strong UV luminescence and the enhanced photocatalytic activity of coupled nanostructures are discussed. Thus the nanocomposite turns out to be suitable for applications in energy harvesting and conversion, gas- and bio-sensing, bio-medicine and filter-free photocatalysis.

Tuberculosis caused by RDRio Mycobacterium tuberculosis is not associated with differential clinical features.

BACKGROUND: We recently described the Mycobacterium tuberculosis RD(Rio) genotype, a clonally derived sublineage within the Latin American-Mediterranean (LAM) family. Genetic diversity of M. tuberculosis likely affects the clinical aspects of tuberculosis (TB). Prospective studies that address this issue are scarce and remain controversial. OBJECTIVE: To determine the association of differential clinical features of pulmonary TB with the RD(Rio) M. tuberculosis etiology. METHODS: Culture-proven pulmonary TB patients (n = 272) were clinically evaluated, including history, physical examination, chest X-ray and anti-human immunodeficiency virus serology. Isolates were classified as RD(Rio) or non-RD(Rio) M. tuberculosis by multiplex polymerase chain reaction and further spoligotyped. Clinical and M. tuberculosis genotype data were analyzed. RESULTS: RD(Rio) M. tuberculosis caused disease in 26.5% (72/270) of all TB cases. The LAM genotype, of which RD(Rio) strains are members, was responsible for 46.0% of the TB cases. Demographic data, major signs and symptoms, radiographic presentation, microbiological features and clinical outcomes were not significantly different among patients with TB caused by RD(Rio) and non-RD(Rio) strains. CONCLUSIONS: Disease caused by M. tuberculosis RD(Rio) strains was not clinically distinctive or more severe than disease caused by non-RD(Rio) strains in this series of TB patients. Larger prospective studies specifically designed to disclose differential clinical characteristics of TB caused by specific M. tuberculosis lineages are needed.

Interleukin-10 and interferon-gamma patterns during tuberculosis treatment: possible association with recurrence.

Interleukin (IL) 10 and interferon-gamma (IFN-) levels in induced sputum supernatants of 21 tuberculosis (TB) patients at diagnosis and during chemotherapy were correlated to recurrence rates. IL-10 decreased until day 60 of treatment (T60), and between T60 and T180 it increased again in 7 cases (Pattern 1) and further decreased in 14 cases (Pattern 2). Follow-up of 69 months was performed in 20/21 cases; 6 had recurrence of TB, of which 5/7 (71%) had Pattern 1 and 1/13 (7.7%) Pattern 2 (OR 30.0, 95%CI 2.19411.3, P 0.0072). This was not observed for IFN-. High IL-10 levels at the end of treatment may function as a risk factor for TB recurrence.

Cognitive profile and MRI findings in limb-girdle muscular dystrophy 2I.

Limb-girdle muscular dystrophy 2I (LGMD2I) is a neuromuscular disorder with a heterogeneous phenotype. It is caused by mutations in the Fukutin Related Protein (FKRP) gene, which is ubiquitously expressed in human tissues. FKRP functions in CNS are largely unknown. To investigate possible cognitive impairment in LGMD2I and to describe brain MRI features. Ten LGMD2I patients (four males and six females, mean age 44 years, age range 19-69 years) were assessed with an extensive neuropsychological battery, psychopathological tests and neuromuscular specific quality-of-life questionnaire. Adults were compared with ten matched healthy controls. All patients underwent complete neurological examination, and nine underwent brain MRI scanning. Patients showed a fairly specific cognitive profile with mild impairment in executive functions and visuo-spatial planning without substantial impairment in global and logic IQ. MRI findings were heterogeneous: four patients showed non-specific white matter abnormalities; two patients showed moderate ventriculomegaly; three patients showed mild enlargement of subarachnoid spaces, without a specific pattern. Cerebellar atrophy was marked in one patient. Abnormal glycosylation of α-dystroglycan in LGMD2I may interfere with brain development and cognitive performances involving the frontal and posterior parietal regions, but does not result in specific brain MRI abnormalities.

Molecular characterization of Echinococcus isolates indicates goats as reservoir for Echinococcus canadensis G6 genotype in Neuquén, Patagonia Argentina.

Human cystic echinococcosis is a highly endemic zoonotic disease in the province of Neuquén, Patagonia Argentina, although a hydatid control programme has been carried out since 1970. Human infection due to Echinococcus canadensis (G6 genotype) is frequent in Neuquén. However, the reservoir for this species remains undetermined in a region where camels are absent. We investigated the fertility, viability and molecular epidemiology of hydatid cysts obtained from local goats, pigs and sheep in order to identify the possible reservoirs of E. canadensis (G6). We also analyzed isolates from infected dogs. A total of 67 isolates were identified by the DNA sequencing of the mitochondrial cytochrome c oxidase subunit 1 gene. Cysts from sheep (n=16), goats (n=23) and pigs (n=18) and adult worms from 10 infected dogs were analyzed. The fertility of the hydatid cysts was 78.6%; 90.4% and 94.4% for sheep, goats and pigs, respectively. We detected E. canadensis (G6) in 21 of 23 goat samples and in 1 dog isolate, E. canadensis (G7) in all the pig isolates, E. granulosus sensu stricto (G3) in 1 sheep and the G1 genotype in 15 sheep, 2 goats and 9 dog samples. The G1 haplotypes included the common sheep strain sequence and 2 microvariants of this sequence. E. granulosus sensu stricto (G3) is described for the first time in South America. We conclude that goats act as reservoir for E. canadensis (G6) in Neuquén, and that control strategies may have to be adapted to local molecular epidemiology to improve the control of parasite transmission.

Usefulness and validation of a coproantigen test for dog echinococcosis screening in the consolidation phase of hydatid control in Neuquén, Argentina.

Hydatidosis is endemic in Neuquén, Patagonia, Argentina, even though sanitary authorities have been performing a control programme since 1970. At present, the programme is in consolidation phase, and dogs have being evaluated by arecoline purgation. The aims of this study were to evaluate diagnostic performance of a coproantigen (CAg) ELISA test developed "in house" and to assess CAg detection in prepatent period. We examined 8 dogs experimentally infected with Echinococcus granulosus and 403 rural dogs in an endemic area in Neuquén using CAg ELISA test and arecoline purgation. Within the experimental dog group, sensitivity and specificity of the test were 93.6% and 88.5% respectively. In rural dogs group, the overall prevalence of canine echinococcosis was 3.7% using arecoline purgation and 12.4% by the CAg test; sensitivity and specificity of the test using arecoline purge as standard were 73.3% and 89.9% respectively. Possible cross reactions in CAg test were evaluated in rural dogs: CAg was undetectable in 96.4% of the dogs infected only with taeniids non-E. granulosus, and in 90.1% of dogs infected with non-taeniid helminths. The CAg test could detect infections within prepatent period and produced negative results after worm expulsion. Our test showed adequate diagnostic performance with experimentally and naturally infected dogs, in the epidemiological situation of Neuquén. Employment of this sensitive and practical method for surveillance in the control programme in Neuquén would improve screening of canine echinococcosis by detecting infected dogs even with low burdens or within prepatent period.

Clinical features of bacterial meningitis in Italy: a multicenter prospective observational study.

We carried out a prospective observational study on clinical features of bacterial meningitis. Between October 2002 and June 2005, 322 adult bacterial meningitis cases in 49 infectious disease wards in Italy (MENTORE study group) were enrolled in the study. 133 cases were due to Streptococcus pneumoniae, 44 to Neisseria meningitidis and 145 to other microorganisms. A high SAPS score and coma on admission, as well as need for mechanical ventilation, were more frequent in the pneumococcal meningitis group. Neurological impairment was present in 151 out of 311 patients, and was more frequent in pneumococcal meningitis. A single antibiotic was employed in only 90 of 315 cases; a combination of ceftriaxone and ampicillin was the most frequently administered treatment. Ceftriaxone was also the single most used drug. Adjunctive treatment with steroids was administered in 210 out of 303 patients for a median duration of 7 days. Median duration of fever was 4 days, and median hospital stay was 16 days; hospitalization was significantly longer in the pneumococcal meningitis group. At discharge, neurological impairment was still present in 59 (21%) of 277 patients. Twenty (6.9%) out of 289 patients died during hospitalization. Distribution of adverse outcome (death and neurological impairment) in patients treated with or without steroids and within different time zones between onset of symptoms and commencement of antibiotics was studied; a trend toward a worse prognosis was seen in patients treated more than 24 hours after onset of the disease.In our study, infectious disease clinicians made extensive use of steroids as adjuvant therapy for bacterial meningitis, even in absence of detailed national and local guidelines. Mortality seemed to be lower in comparison with the literature.

Low expression of antigen-presenting and costimulatory molecules by lung cells from tuberculosis patients

Costimulatory and antigen-presenting molecules are essential to the initiation of T cell immunity to mycobacteria. The present study analyzed by immunocytochemistry, using monoclonal antibodies and alkaline phosphatase-anti-alkaline phosphatase method, the frequency of costimulatory (CD86, CD40, CD40L, CD28, and CD152) and antigen-presenting (MHC class II and CD1) molecules expression on human lung cells recovered by sputum induction from tuberculosis (TB) patients (N = 22) and non-TB controls (N = 17). TB cases showed a statistically significant lower percentage of HLA-DR+ cells than control subjects (21.9 ± 4.2 vs 50.0 ± 7.2 percent, P < 0.001), even though similar proportions of TB cases (18/22) and control subjects (16/17, P = 0.36) had HLA-DR-positive-stained cells. In addition, fewer TB cases (10/22) compared to control subjects (16/17) possessed CD86-expressing cells (P = 0.04; OR: 0.05; 95 percentCI = 0.00-0.51), and TB cases expressed a lower percentage of CD86+ cells (P = 0.04). Moreover, TB patients with clinically limited disease (£1 lobe) on chest X-ray exhibited a lower percentage of CD86-bearing cells compared to patients with more extensive lung disease (>1 lobe) (P = 0.02). The lower expression by lung cells from TB patients of HLA-DR and CD86, molecules involved in antigen presentation and activation of T cells, may minimize T cell recognition of Mycobacterium tuberculosis, fostering an immune dysfunctional state and active TB.

Low expression of antigen-presenting and costimulatory molecules by lung cells from tuberculosis patients.

Costimulatory and antigen-presenting molecules are essential to the initiation of T cell immunity to mycobacteria. The present study analyzed by immunocytochemistry, using monoclonal antibodies and alkaline phosphatase-anti-alkaline phosphatase method, the frequency of costimulatory (CD86, CD40, CD40L, CD28, and CD152) and antigen-presenting (MHC class II and CD1) molecules expression on human lung cells recovered by sputum induction from tuberculosis (TB) patients (N = 22) and non-TB controls (N = 17). TB cases showed a statistically significant lower percentage of HLA-DR+ cells than control subjects (21.9 +/- 4.2 vs 50.0 +/- 7.2%, P < 0.001), even though similar proportions of TB cases (18/22) and control subjects (16/17, P = 0.36) had HLA-DR-positive-stained cells. In addition, fewer TB cases (10/22) compared to control subjects (16/17) possessed CD86-expressing cells (P = 0.04; OR: 0.05; 95%CI = 0.00-0.51), and TB cases expressed a lower percentage of CD86+ cells (P = 0.04). Moreover, TB patients with clinically limited disease ( pound1 lobe) on chest X-ray exhibited a lower percentage of CD86-bearing cells compared to patients with more extensive lung disease (>1 lobe) (P = 0.02). The lower expression by lung cells from TB patients of HLA-DR and CD86, molecules involved in antigen presentation and activation of T cells, may minimize T cell recognition of Mycobacterium tuberculosis, fostering an immune dysfunctional state and active TB.

Experimental osteomyelitis: what have we learned from animal studies about the systemic treatment of osteomyelitis?

Clinical trials of systemic antibiotic treatment of osteomyelitis are difficult to perform for many reasons, such as low incidence rate of osteomyelitis, variety of anatomic locations, stage and etiologic agents. In this article, we reviewed the experimental studies on osteomyelitis available in the English medical literature since 1968, to ascertain their actual and potential impact on the treatment of human osteomyelitis. Major results are summarized and topics of major interest, such as reproducibility of animal models, predictive value of animal models, correlation of pharmacokinetics between different animals and humans, and the correlation of outcome between animal and clinical studies are discussed. Most of the reviewed animal models are reproducible and dependable. However, establishing the right dose regimen in animals appeared a critical factor, which might undermine the predictive value of the experimental study. Due to difficulties in comparing results of animal and human studies, the predictive value of animal studies about osteomyelitis is still unclear. However, animal models gave valuable information to the clinician for choosing the minimal duration of antibiotic treatment. Even though the use of antibiotic combinations was associated with better outcome in the majority of animal studies, such a finding seems to have limited impact on clinical practice.

Human leptospirosis in the Vicenza area (Italy) from 1990 to 2003: an epidemiological and clinical study.

All cases of human leptospirosis observed at the S. Bortolo Hospital, Vicenza, Italy, in the period from September 1990 to December 2003 were retrospectively reviewed. The aim of the study was to define the epidemiological, clinical, diagnostic, and therapeutic aspects of this infection and to compare these with an earlier local study (1979-1990) in order to assess if any changes have occurred over time. The screening test was made using macroscopic agglutination and the diagnosis was definitively confirmed using the microscopic agglutination test (MAT). The etiological serotype was identified in 13 patients (68%) and Leptospira poi was the most frequent serovar. Hepatic and renal involvements were present in a high percentage of patients (71% and 74%, respectively), cardiac involvement in 39%, and hypertriglyceridemia and hepatic steatosis were observed in 68% and 43% of cases, respectively. One patient died because of acute renal and respiratory failure. Intravenous penicillin was the treatment of choice. A consistent reduction in the prevalence was observed during the time period of this study (n = 38) compared with the previous period (n = 86); males were more affected than females in both time periods. In industrialized countries the prevalence of leptospirosis is decreasing; nevertheless, this infection is no longer limited to specific occupational groups and remains a potential fatal disease that should be included in the differential diagnosis of all the patients with unexplained fever.

Clostridial orthopedic infections: case reports and review of the literature.

Clostridia are anaerobic Gram-positive bacilli that can be isolated from the soil and the intestinal tract of humans. These microorganisms are recognized as the cause of devastating soft tissue infections, such as cellulitis, myositis, and gas gangrene. However, such bacteria may also be involved in various postoperative orthopedic infections, including prosthetic joint infection. We present three clinical cases of clostridial orthopedic infection and review the related medical literature.