Aerosol source apportionment uncertainty linked to the choice of input chemical components

For a Positive Matrix Factorization (PMF) aerosol source apportionment (SA) studies there is no standard procedure to select the most appropriate chemical components to be included in the input dataset for a given site typology, nor specific recommendations in this direction. However, these choices are crucial for the final SA outputs not only in terms of number of sources identified but also, and consequently, in the source contributions estimates. In fact, PMF tends to reproduce most of PM mass measured independently and introduced as a total variable in the input data, regardless of the percentage of PM mass which has been chemically characterized, so that the lack of some specific source tracers (e.g. levoglucosan) can potentially affect the results of the whole source apportionment study. The present study elaborates further on the same concept, evaluating quantitatively the impact of lacking specific sources' tracers on the whole source apportionment, both in terms of identified sources and source contributions. This work aims to provide first recommendations on the most suitable and critical components to be included in PMF analyses in order to reduce PMF output uncertainty as much as possible, and better represent the most commons PM sources observed in many sites in Western countries. To this aim, we performed three sensitivity analyses on three different datasets across EU, including extended sets of organic tracers, in order to cover different types of urban conditions (Mediterranean, Continental, and Alpine), source types, and PM fractions. Our findings reveal that the vehicle exhaust source resulted to be less sensitive to the choice of analytes, although source contributions estimates can deviate significantly up to 44 %. On the other hand, for the detection of the non-exhaust one is clearly necessary to analyze specific inorganic elements. The choice of not analysing non-polar organics likely causes the loss of separation of exhaust and non-exhaust factors, thus obtaining a unique road traffic source, which provokes a significant bias of total contribution. Levoglucosan was, in most cases, crucial to identify biomass burning contributions in Milan and in Barcelona, in spite of the presence of PAHs in Barcelona, while for the case of Grenoble, even discarding levoglucosan, the presence of PAHs allowed identifying the BB factor. Modifying the rest of analytes provoke a systematic underestimation of biomass burning source contributions. SIA factors resulted to be generally overestimated with respect to the base case analysis, also in the case that ions were not included in the PMF analysis. Trace elements were crucial to identify shipping emissions (V and Ni) and industrial sources (Pb, Ni, Br, Zn, Mn, Cd and As). When changing the rest of input variables, the uncertainty was narrow for shipping but large for industrial processes. Major and trace elements were also crucial to identify the mineral/soil factor at all cities. Biogenic SOA and Anthropogenic SOA factors were sensitive to the presence of their molecular tracers, since the availability of OC alone is unable to separate a SOA factor. Arabitol and sorbitol were crucial to detecting fungal spores while odd number of higher alkanes (C27 to C31) for plant debris.

Characterization of Agfa Structurix series D4 and D3sc x-ray films in the 0.7-4.6 keV energy range

X-ray films remain a key asset for high-resolution x-ray spectral imaging in high-energy-density experiments conducted at the National Ignition Facility (NIF). The soft x-ray Opacity Spectrometer (OpSpec) fielded at the NIF has an elliptically shaped crystal design that measures x rays in the 900-2100 eV range and currently uses an image plate as the detecting medium. However, Agfa D4 and D3sc x-ray films' higher spatial resolution provides increased spectral resolution to the data over the IP-TR image plates, driving the desire for regular use of x-ray film as a detecting medium. The calibration of Agfa D4 x-ray film for use in the OpSpec is communicated here. These calibration efforts are vital to the accuracy of the NIF opacity measurements and are conducted in a previously un-studied x-ray energy range under a new film development protocol required by NIF. The absolute response of Agfa D4 x-ray film from 705 to 4620 eV has been measured using the Nevada National Security Site Manson x-ray source. A broader range of energies was selected to compare results with previously published data. The measurements were taken using selected anodes, filters, and applied voltages to produce well-defined energy lines.

Impact of De-escalation on Prognosis of Patients With Bacteremia due to Enterobacteriaceae: A Post Hoc Analysis From a Multicenter Prospective Cohort

Background

More data are needed about the safety of antibiotic de-escalation in specific clinical situations as a strategy to reduce exposure to broad-spectrum antibiotics. The aims of this study were to investigate predictors of de-escalation and its impact on the outcome of patients with bloodstream infection due to Enterobacteriaceae (BSI-E).

Methods

A post hoc analysis was performed on a prospective, multicenter cohort of patients with BSI-E initially treated with ertapenem or antipseudomonal β-lactams. Logistic regression was used to analyze factors associated with early de-escalation (EDE) and Cox regression for the impact of EDE and late de-escalation (LDE) on 30-day all-cause mortality. A propensity score (PS) for EDE vs no de-escalation (NDE) was calculated. Failure at end of treatment and length of hospital stay were also analyzed.

Results

Overall, 516 patients were included. EDE was performed in 241 patients (46%), LDE in 95 (18%), and NDE in 180 (35%). Variables independently associated with a lower probability of EDE were multidrug-resistant isolates (odds ratio [OR], 0.50 [95% confidence interval {CI}, .30–.83]) and nosocomial infection empirically treated with imipenem or meropenem (OR, 0.35 [95% CI, .14–.87]). After controlling for confounders, EDE was not associated with increased risk of mortality; hazard ratios (HR) (95% CIs) were as follows: general model, 0.58 (.25–1.31); model with PS, 0.69 (.29–1.65); and PS-based matched pairs, 0.98 (.76–1.26). LDE was not associated with mortality. De-escalation was not associated with clinical failure or length of hospital stay.

Conclusions

De-escalation in patients with monomicrobial bacteremia due to Enterobacteriaceae was not associated with a detrimental impact on clinical outcome.

Non-destructive determination of uranium, thorium and 40K in tobacco and their implication on radiation dose levels to the human body

The naturally occurring radionuclides of (235)U, (238)U and (232)Th and their daughter products are a potential major source of anthropogenic radiation to tobacco smokers. Often overlooked is the presence of (40)K in tobacco and its implication to radiation dose accumulation in the human body. In this study, these three radiation sources have been determined in four typical US cigarettes using neutron activation analysis (NAA). The NAA reactions of (238)U(n,γ)(239)U, (232)Th(n,γ)(233)Th and (41)K(n,γ)(42)K were used to determine (235)U, (238)U and (232)Th and (40)K, respectively. The activity of (238)U can easily be determined by epithermal NAA of the (238)U(n,γ)(239)U reaction, and the activity of (235, 234)U can easily be deduced. Using isotopic ratios, the activity due to (40)K was found by the determined concentrations of (41)K (also by epithermal neutrons) in the bulk material. Each gram of total potassium yields 30 Bq of (40)K. The annual effective dose for smokers using 20 cigarettes per day was calculate to be 14.6, 137 and 9 μSv y(-1) for (238,235,) (234)U, (232)Th and (40)K, respectively. These values are significantly lower that the dose received from (210)Po except for (232)Th.

Pretransplant interferon-γ secretion by CMV-specific CD8+ T cells informs the risk of CMV replication after transplantation

In this prospective study we analyzed pretransplant interferon-γ secretion by cytomegalovirus (CMV)-specific CD8+ T cells to assess its possible utility in determining the risk of CMV replication after solid organ transplantation. A total of 113 lung and kidney transplant patients were enrolled in the study but only 55 were evaluable. All CMV-seronegative recipients were pretransplant "nonreactive" (IFNγ <0.2 IU/mL) (11/11), whereas 30/44 (68.2%) CMV-seropositive (R+) recipients were "reactive" (IFNγ ≥0.2 IU/mL) and 14/44 (31.8%) were "nonreactive". In the R(+) "nonreactive" group, 7/14 (50%) developed posttransplant CMV replication, whereas the virus replicated only in 4/30 (13.3%) of the R(+) "reactive" patients (p = 0.021). According to the best multivariate model, pretransplant "nonreactive" recipients receiving an organ from a CMV-seropositive donor had a 10-fold increased risk of CMV replication compared to pretransplant "reactive" recipients (adjusted OR 10.49, 95% CI 1.88-58.46). This model displayed good discrimination ability (AUC 0.80) and calibration (Hosmer-Lemeshow test, p = 0.92). Negative and positive predictive values were 83.7% and 75%, respectively. The accuracy of the model was 82%. Therefore, assessment of interferon-γ secretion by cytomegalovirus (CMV)-specific CD8+ T cells prior to transplantation is useful in informing the risk of posttransplant CMV replication in solid organ transplant patients.

Therapy with m-TOR inhibitors decreases the response to the pandemic influenza A H1N1 vaccine in solid organ transplant recipients

Concern has been raised regarding the response to vaccination in solid organ transplant recipients (SOTR) undergoing immunosuppressant regimens and the possibility of rejection related to the immune response associated with pandemic influenza H1N1-2009 vaccination. The goal of this study was to assess the immunogenicity, efficacy and safety of the pandemic vaccine in SOTR. We performed a multicenter prospective study in SOTR receiving the pandemic vaccine. Immunological response was determined in serum 5 weeks after vaccination by microneutralization assays, and immunoglobulins were measured by ELISA. Three hundred and forty-six SOTR were included. Preexisting seroprotection was detected in 13.6% of cases and rates of seroconversion and seroprotection after vaccination were 73.1% and 82.9%, respectively. Patients with baseline antibody titers had better geometric mean titers (GMT)-post after pandemic vaccination (339.4 vs. 121.4, p < 0.001). Younger age, liver disease and m-TOR inhibitor therapy were independently associated with lower seroprotection and GMT-post. There were no major adverse effects or rejection episodes. Pandemic vaccine was safe in SOTR and elicited an adequate response, although lower than in healthy individuals. This is the first study describing a decreased response after vaccination in patients receiving mTOR inhibitors who presented lower seroprotection rates and lower GMT-post.

An siRNA screen identifies RSK1 as a key modulator of lung cancer metastasis

We performed a kinome-wide siRNA screen and identified 70 kinases altering cell migration in A549 lung cancer cells. In particular, ribosomal S6 kinase 1 (RSK1) silencing increased, whereas RSK2 and RSK4 downregulation inhibited cell motility. In a secondary collagen-based three-dimensional invasion screen, 38 of our hits cross-validated, including RSK1 and RSK4. In two further lung cancer cell lines, RSK1 but not RSK4 silencing showed identical modulation of cell motility. We therefore selected RSK1 for further investigation. Bioinformatic analysis followed by co-immunoprecipitation-based validation revealed that the actin regulators VASP and Mena interact with RSK1. Moreover, RSK1 phosphorylated VASP on T278, a site regulating its binding to actin. In addition, silencing of RSK1 enhanced the metastatic potential of these cells in vivo using a zebrafish model. Finally, we investigated the relevance of this finding in human lung cancer samples. In isogenically matched tissue, RSK1 was reduced in metastatic versus primary lung cancer lesions. Moreover, patients with RSK1-negative lung tumours showed increased number of metastases. Our results suggest that the findings of our high-throughput in vitro screen can reliably identify relevant clinical targets and as a proof of principle, RSK1 may provide a biomarker for metastasis in lung cancer patients.

Yes-associated protein (YAP) functions as a tumor suppressor in breast

Yes-associated protein (YAP) has been shown to positively regulate p53 family members and to be negatively regulated by the AKT proto-oncogene product in promoting apoptosis. On the basis of this function and its location at 11q22.2, a site of frequent loss of heterozygosity (LOH) in breast cancer, we investigated whether YAP is a tumor suppressor in breast. Examination of tumors by immunohistochemistry demonstrated significant loss of YAP protein. LOH analysis revealed that protein loss correlates with specific deletion of the YAP gene locus. Functionally, short hairpin RNA knockdown of YAP in breast cell lines suppressed anoikis, increased migration and invasiveness, inhibited the response to taxol and enhanced tumor growth in nude mice. This is the first report indicating YAP as a tumor suppressor, revealing its decreased expression in breast cancer as well as demonstrating the functional implications of YAP loss in several aspects of cancer signaling.

FMR1 CGG repeat length predicts motor dysfunction in premutation carriers

BACKGROUND

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a recently described, underrecognized neurodegenerative disorder of aging fragile X mental retardation 1 (FMR1) premutation carriers, particularly men. Core motor features are action tremor, gait ataxia, and parkinsonism. Carriers have expanded CGG repeats (55 to 200); larger expansions cause fragile X syndrome, the most common heritable cause of mental retardation and autism. This study determines whether CGG repeat length correlates with severity and type of motor dysfunction in premutation carriers.

METHODS

Persons aged >or=50 years with a family history of fragile X syndrome underwent structured videotaping. Movement disorder neurologists, blinded to carrier status, scored the tapes using modified standardized rating scales. CGG repeat length analyses for women incorporated the activation ratio, which measures the percentage of normal active chromosome X alleles.

RESULTS

Male carriers (n = 54) had significantly worse total motor scores, especially in tremor and ataxia, than age-matched male noncarriers (n = 51). There was a trend toward a difference between women carriers (n = 82) and noncarriers (n = 39). In men, increasing CGG repeat correlated with greater impairment in all motor signs. In women, when activation ratio was considered, increasing CGG correlated with greater ataxia.

CONCLUSIONS

CGG repeat size is significantly associated with overall motor impairment in premutation carriers. Whereas this association is most pronounced for men and covers overall motor impairment-tremor, ataxia, and parkinsonism-the association exists for ataxia among women carriers. This is the first report of a significant correlation between the premutation status and a motor feature of fragile X-associated tremor/ataxia syndrome in women.

Trace element determination of Argentine wines using ETAAS and USN-ICP-OES

The objective of this work was to develop a method to determine the metal content in wine samples from the province of Mendoza in Argentina. Ten samples of white wine and 10 samples of red wine available in the supermarket were analyzed for the metals aluminium, cadmium, calcium, chromium, copper, iron, nickel, lead and zinc by electrothermal atomic spectrometry (ETAAS) and ultrasonic nebulization was coupled to inductively coupled plasma optical emission spectrometry (USN-ICP-OES). The aluminium, cadmium, calcium, copper, iron, lead, zinc, chromium concentrations were between 17.0-18.0 microg l(-1), 1.0-4.7microg l(-1), 10.0-15.0 mg l(-1), 23.0-28.0 microg l(-1), 480-790 microg l(-1), 50-90 microg l(-1), 24-130 microg l(-1), and <0.2-6.25 microg l(-1), respectively. The levels compare well with those reported for similar wines from some other parts of the world. A significant aspect in this paper is the samples mineralization step, which allowed the direct determination of the metals. Concerning to the Cd determination, a refluxing digestion system was used for the pretreatment of the samples.

[Tenosynovitis caused by ciprofloxacin. Clinical case]

We report a 67 years old diabetic female that received ciprofloxacin for an acute pyelonephritis. Twelve days after starting this treatment, a hand and forearm tenosynovitis appeared, that subsided after the discontinuation of ciprofloxacin. Literature review disclosed other reports of tenosynovitis associated with the use of this antimicrobial.

[Application of intrauterine device through the incision of the cesarean section]

Intrauterine devices (IUDs) were applied in 554 women during cesarean sections and the results were compared with the event rates presented in 804 women who received the IUD vaginally immediately postpartum. The expulsion rates at one month were 4.1 for the IUD inserted during the cesarean section and 7.5 for the post partum IUD. The expulsion rates at three months were 10.9 and 16.4 respectively. In a third group of 240 women who had cesarean sections but did not accept the IUD for contraception, the rate of endometritis at one month resulted in 0.8 compared with 1.1 for the group of cesarean section with IUD. Almost two thirds of the cesarean sections in both groups were performed on emergency bases. The application of the transcesarean IUD is considered to be safe procedure for fertility control.

A neural model of interactions subserving prey-predator discrimination and size preference in anuran amphibia

The model described is an extension of a previous model of the optic tectum (Arbib & Lara, 1982; Lara, Arbib & Cromarty, 1982; Lara & Arbib, 1982) and takes into consideration anatomical, physiological and behavioral studies in anurans, as well as earlier modelling efforts (Ewert & Von Seelen, 1974; Didday, 1976). Computer simulations were conducted to analyze how interactions among retina, optic tectum and pretectum may give frogs and toads the ability to discriminate between prey and predator stimuli. Results from simulations have allowed us to reproduce empirical observations, to suggest new experiments, and to postulate what neural mechanisms might be involved in some phenomena related to prey-catching orienting behavior, with direction invariance of prey-predator recognition being a consequence of tectal architecture, and size preference and response latency depending on the motivational state of the animal.

A global model of the neural mechanisms responsible for visuomotor coordination in toads

A model of how the nervous system of toads processes visual information to control motor behaviour is proposed. The problem of visuomotor coordination in toads is studied through the integration of two different approaches: a top-down approach through schema theory developed in the studies of cognitive psychology, artificial intelligence and brain theory; and a bottom-up approach through the integration of physiological, anatomical, ethological, and neural modelling. The model proposes that visual information is processed in a parallel distributed way through different brain layers whose interaction defines the proper motor response for that specific situation. It is postulated that visual processing of information is organized into main schemata, which set the goal to be attained and, depending on the specific circumstances of the animal, activates different brain layers; the main schemata may use other schemata to solve a specific subproblem to reach the schemata, and a programme of schema co-ordination. With this model we have simulated how toads plan their route to reach a prey or the route to go away form a predator, depending on the state of their three-dimensional world. The model postulates specific hypotheses that could be tested experimentally on the processing of information in the toad's nervous system.

[2-dimensional echocardiography in fixed fibrous subaortic stenosis. Correlation with hemodynamics and M-mode echocardiography]

Comparative diagnostic capacity is analyzed between two dimensional echocardiography (E-BD), hemodynamics, surgery and the M-Mode, to accurately establish the diagnosis, variety and severity of fixed fibrous subaortic stenosis, in 29 patients, whose previous diagnosis were made by two dimensional images, using paraesternal, apical and subxiphoid long axis. Group I is made up of 17 patients who had two dimensional echocardiography, M-Mode, and catheterization; Group II is composed of 12 patients who only had two-dimensional echocardiography and M-Mode. Within Group I, hemodynamics showed subaortic gradient in 81%, transvalvular in 13% and no gradient in 6%; the ventriculography showed subaortic obstruction only in 59% of the patients and was normal in 41%. The M-Mode echocardiography registered protosystolic aortic closure (CPSAo) in 50%; the subaortic obstruction was seen as a band, in 44%, non-specific echoes in the outflow tract in 12% and this was normal in 44%. The two cases with transvalvular gradient, the M-Mode registered the subaortic band, and in the case without gradient, the ventriculography showed the subvalvular obstruction. In Group II, the diagnostic signs of M-Mode were: CPSAo in 58%, band in 17%, non specific echoes in the outflow tract in 8%, and this was normal in 75%. The results support other data in that two-dimensional Echocardiography is more sensitive and more specific than M-Mode, intraventricular pressure curves and ventriculography.(ABSTRACT TRUNCATED AT 250 WORDS)

Synaptic competition in developmental binocular plasticity

A mathematical model of the possible physiological and biochemical mechanisms responsible for the changes occurring during binocular development is proposed. The model is based on the mechanisms postulated for the occurrence of well known plastic processes, such as post-tetanic potentiation, sensitization and heterosynaptic inhibition. Because all these processes are of presynaptic nature, we have postulated that the plastic processes occurring during development are of the same nature. The factors we have considered in our model are: the transmitter pool size, the mobilization or synthesis of the transmitter, the transmitter release by the physiological stimulus, the neuroendocrine and genetic activity. With this model we have simulated the following phenomena during ocular development: (1) normal binocular development; (2) monocular deprivation, including the effects of reversing the occluded eye; (3) binocular deprivation and recovery; and (4) effects of alternating deprivation on mature binocularity. The model also allows us to explain in a natural way the possible changes occurring during denervation or disuse.

Chondroid chordoma. Case report

✓ A case of the very rare chondroid variant of chordomas at the base of the skull is presented. The characteristic presentation, radiological and computerized tomographic appearance, findings at surgery, pathology, and treatment of this lesion are discussed. Neurosurgeons should be aware of this variant, due to its predilection for occurrence at the base of the skull and its more favorable prognosis compared with that of typical chordoma.

The role of the tectal column in facilitation of amphibian prey-catching behavior: a neural model

We used computer analysis of differential equations to study the properties of a family of models of a unit of neural circuitry in the amphibian tectum, the tectal column. Computer experiments were used to discriminate among various hypotheses and to suggest new experiments. Particular attention was paid to physiological data on facilitation of amphibian prey-catching behavior which led us to model the facilitation in terms of dynamic activity in the tectal column rather than in terms of synaptic modification.

A neural model of the interaction of tectal columns in prey-catching behavior

Building on a simple model of a tectal column as the unit of processing in the amphibian tectum, we conduct a computer analysis of the interaction of a linear array of such columns. The model suggests that the inhibitory and excitatory activity in the tectum may have three functions: 1) spatio-temporal facilitation of column activity to a moving stimulus; 2) preference for the head of the stimulus, probably to avoid possible defensive reactions of the prey; and 3) modulating the state of excitation of the column once it has produced a response. The model also shows that the spatio-temporal effects of excitation and inhibition increases the acuity of the animal to the direction of the prey, through processes similar to lateral inhibition.

Mathematical models of synaptic plasticity: I. Posttetanic potentiation

A mathematical model of post-tetanic potentiation is proposed. The model uses differential equations and is based upon physiological postulates of the electrical, metabolic, and neuroendocrine activities that are related to synaptic connectivity. These activities may modify some important parameters in synaptic function. In the proposed model these parameters are restricted to the presynapse in view of the physiological evidence indicating that posttetanic potentiation is probably due to presynaptic mechanisms. The model takes into consideration the size of the transmitter pool available for release, the mobilization of transmitter from and to this pool, and the fraction of transmitter released. Based upon the above postulates, we have simulated different phases of the phenomenon of posttetanic potentiation, and we have presented the results of several preparations in which this event has been studied. This work represents a successful attempt to reproduce the dynamics of posttetanic potentiation based upon physiological results with a mathematical model.

Mathematical model of synaptic plasticity: III. Heterosynaptic changes

A mathematical model, using differential equations, of heterosynaptic plasticity is proposed. The model is based on physiological studies of invertebrates in which nonspecific conditioning, such as sensitization and heterosynaptic inhibition, starts to be elucidated and behavioral studies of classical and instrumental conditioning, which we postulate to have the same mechanisms as those found in nonspecific conditioning. The model permits us to simulate the following heterosynaptic changes: sensitization, heterosynaptic inhibition, classical and instrumental conditioning--including short- and long-term memory--extinction and recuperation--spontaneously and by stimulation.

Mathematical model of synaptic plasticity: II. Habituation

A mathematical model of the phenomenon of habituation as a homosynaptic depression of the amount of transmitter release is proposed. The model is based on the physiological studies of habituation in invertebrates and in the spinal cord of vertebrates, where a single synapse has been isolated and some of the physiological mechanisms of this process have been elucidated. The model simulates the following properties of habituation: (1) reduced amount of transmitter release attributed to a repetitive stimulus through changes in the membrane permeability to Ca2+ ions; (2) spontaneous recovery by rest; (3) the amplitude and frequency dependence of habituation; (4) modulation of habituation: sensitization, through an increase in membrane Ca2+ permeability, and presynaptic inhibition, through a reduced depolarization of the physiological stimulus; (5) long-term habituation attributed to repetitive trials of habituation and spontaneous recovery.

[Height of children with G. lamblia and there capacity to absorb d-xylose]

The investigation was carried out with the purpose of studying the capacity to absorb d-xylose in children with G. lamblia establishing also, whether or not their height was reduced. The study is included 25 school age children with giardiasis, pairing them according to sex and age with another 25 without intestinal parasitosis.

[Absorption of D-xylose in intestinal parasitic diseases]

In order to investigate the intestinal absorption in relation to parasitic diseases, 106 children were studied using the xylose test. All of them were attending a primary school. The height and weight were recorded, and the hemoblobin and hematocrit were estimated in each one. The examination of the stools shown one or more parasites in 57.6 per cent specimens. The E. histolytica, Hymenolepis nana and A. lumbricoides, were identified in 22.6, 21.7 and 20.7 per cent children, respectively; G lamblia was found in 10.4 per cent. Only the children with Giardia had a statistical difference in the absorption of xylose, with respect to those without parasites. At the same time height was low in comparison to a group of children with similar age and sex, selected among the 45 without parasitic diseases. Findings are discussed according to the pathogenic mechanism involved in giardiasis. Emphasis is done in the interplay of malnutrition and G. lamblia.

Extradural toruloma in the lumbo-sacral region

An extradural toruloma developed in the lumbo-sacral region of a man. Symptoms had been present for two years, but he had been diagnosed as having tuberculosis of the lung seven years before. The mass was excised and the patient treated with Amphotericin B which had to be discontinued and Sulfa Soxizole substituted. He recovered and has remained symptom free for three years.