Pathogenicity of microsclerotia from Metarhizium robertsii against Aedes aegypti larvae and antimicrobial peptides expression by mosquitoes during fungal-host interaction

Aedes aegypti is a vector of various disease-causing arboviruses. Chemical insecticide-based methods for mosquito control have increased resistance in different parts of the world. Thus, alternative control agents such as the entomopathogenic fungi are excellent candidates to control mosquitoes as part of an ecofriendly strategy. There is evidence of the potential of entomopathogenic fungal conidia and blastospores for biological control of eggs, larval and adult stages, as well as the pathogenicity of fungal microsclerotia against adults and eggs. However, there are no studies on the pathogenicity of microsclerotia against either aquatic insects or insects that develop part of their life cycle in the water, such as the A. aegypti larvae. In this study, we assayed the production of microsclerotia and their pathogenicity against A. aegypti larvae of two isolates of Metarhizium robertsii, i.e., CEP 423 isolated in La Plata, Argentina, and the model ARSEF 2575. Both isolates significantly reduced the survival of A. aegypti exposed to their microsclerotia. The fungus-larva interaction resulted in a delayed response in the host. This was evidenced by the expression of some humoral immune system genes such as defensins and cecropin on the 9th day post-infection, when the fungal infection was consolidated as a successful process that culminates in larvae mortality. In conclusion, M. robertsii microsclerotia are promising propagules to be applied as biological control agents against mosquitoes since they produce pathogenic conidia against A. aegypti larvae.

Dark Pigments in Entomopathogenic Fungal Microsclerotia: Preliminary Evidence of a 1,8-Dihydroxynaphthalene-melanin-like Compound in Metarhizium robertsii

Metarhizium robertsii microsclerotia are fungal aggregates composed of compacted, pigmented hyphae. As they are highly tolerant to desiccation and produce infective conidia, they are promising candidates to be formulated as bioinsecticides. Despite this potential, the nature of the pigments within these structures remains unclear. In this study, routine culture media used for the differentiation of M. robertsii microsclerotia were supplemented with four melanin inhibitors, and the resulting propagules were characterized. Inhibitors of the 1,8-dihydroxynaphthalene (DHN)-melanin biosynthetic pathway such as tricyclazole and guaiacol induced significant phenotypic and molecular modifications in the obtained M. robertsii propagules, which exhibited a more spherical shape, reduced size, and increased susceptibility to desiccation, heat, and oxidative stress than microsclerotia obtained without inhibitors. Additionally, genes encoding for a polyketide synthase (Mrpks2) and a putative 1,3,6,8-tetrahydroxynaphthalene reductase (Mrthnr), potentially involved in the DHN-melanin biosynthetic pathway, were upregulated in fungi grown in the inhibitor-added media. In conclusion, M. robertsii microsclerotia contain melanins of type DHN that might play a role in both microsclerotia differentiation and environmental stress tolerance.

A standard set of person-centred outcomes for diabetes mellitus: results of an international and unified approach

AIMS

To select a core list of standard outcomes for diabetes to be routinely applied internationally, including patient-reported outcomes.

METHODS

We conducted a structured systematic review of outcome measures, focusing on adults with either type 1 or type 2 diabetes. This process was followed by a consensus-driven modified Delphi panel, including a multidisciplinary group of academics, health professionals and people with diabetes. External feedback to validate the set of outcome measures was sought from people with diabetes and health professionals.

RESULTS

The panel identified an essential set of clinical outcomes related to diabetes control, acute events, chronic complications, health service utilisation, and survival that can be measured using routine administrative data and/or clinical records. Three instruments were recommended for annual measurement of patient-reported outcome measures: the WHO Well-Being Index for psychological well-being; the depression module of the Patient Health Questionnaire for depression; and the Problem Areas in Diabetes scale for diabetes distress. A range of factors related to demographic, diagnostic profile, lifestyle, social support and treatment of diabetes were also identified for case-mix adjustment.

CONCLUSIONS

We recommend the standard set identified in this study for use in routine practice to monitor, benchmark and improve diabetes care. The inclusion of patient-reported outcomes enables people living with diabetes to report directly on their condition in a structured way.

Land Use Regression Model for Exposure Assessment to PM2.5 and PM10 in Rio de Janeiro, Brazil

Background

Air pollution is a major public health problem. The latest data from World Health Organization show that 9 out of 10 people breathe air containing high levels of pollutants and that about 4.2 million deaths were caused by exposure to fine particles in 2016. Therefore, the aim of our study was to elaborate a model for long-term exposure assessment to air pollution.

Methods

This study was developed in Rio de Janeiro city, it has 1,200.255 km² large, about 6.7 million residents and located in the southeastern region of Brazil. The information of PM2.5, PM10 and predictor variables were obtained from government agencies. The potential predictor variables have been used: temperature, relative humidity, vehicular traffic base, Census, altitude databases, vegetation cover, land use, rock masses, hydrographic and hydrographic sub-basins, urban zoning and road network. For the development of Land Use Regression models, linear regression models were specified using the supervised stepwise procedure. Cook D statistics were used to detect influential observations. The overall model performance was evaluated by leave-one-out cross validation (LOOCV).

Results

The annual mean of PM2.5 and PM10 was 11.73 (SD = ± 4.84) and 35.57 (SD = ± 8.91) μg·m−3, respectively. The R2 value in the final model for PM2.5 was 0.3812 and p-value: 0.0907. The performance evaluated by LOOCV was not also good, the RMSE was 0.2920, with R2 value of 0.1820. The R2 value in the final model for PM10 was 0.73, p-value: 0.001. The performance evaluated by LOOCV was also good, the RMSE was 0.1386, with R2 value of 0.5832.

Conclusions

The model could be applied in areas where there is no monitoring of air quality, thus, enabling the evaluation of the health impact of exposed populations, providing support for decision-making and development of public and investments policies, medium impact and long-term, more targeted in the following areas: health, environment, transportation and urban planning.

Key messages

Oswaldo Cruz Foundation. Universidade do Estado do Rio de Janeiro.

FRI0605-HPR MORTALITY AND SURVIVAL IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS IN ARGENTINA. A MULTICENTER STUDY ON BEHALF GESAR-LES

Background:

The mortality rate in patients with systemic lupus erythematosus (SLE) is 2–3 times higher than in the general population. However, survival in these patients has improved significantly and is currently 95% at 5 years according to different studies. Since the last 20 years, there are no new reports on this issue in Argentina.

Objectives:

To analyze the factors associated with mortality, survival and causes of death in patients with SLE.

Methods:

Longitudinal - multicenter study, in which 10 rheumatology centers of Argentina participated. Patients with SLE (ACR 1997 and / or SLICC 2012 criteria) with a minimum follow-up of 6 months monitored between January 2008 and December 2018 were included. Demographic, clinical, laboratory, therapeutic variables (treatments received during the evolution of the disease and within 60 days prior to death or last control); mortality, causes of death and survival at 5, 10 and 20 years were evaluated. Statistical analysis: descriptive statistics, Kaplan-Meier survival curves and Cox regression model.

Results:

Three hundred and eighty two patients were included; 90% women and 82% mestizos. The mean of evolution time of SLE was 4.1 ± 6.7 years. The mean age at the last control or death was 37.2 ± 12.7 years, SLEDAI 3.2 ± 4.2 and SLICC 1.2 ± 1.9.

Mortality was 12% (95% CI [8-15]) and the causes of death were: Infections (27), cardiovascular disease (6), SLE activity (3), catastrophic antiphospholipid syndrome (2) and other causes (8). Using the variables associated with mortality in different Cox regression models, the variables that increased the risk of death significantly were: renal involvement (RR 3.3), cardiac involvement (RR 2.7), central nervous system involvement (RR 2.1), arterial thrombosis (RR 2.3), hyperlipemia (RR 2.4), number of infections (RR 1.2) and last SLEDAI (1.1).

The time of HCQ use greater than 36 months decreased the risk of death in this cohort by 40% (p 0.03). Prednisone (maximum dose and time) was not associated with mortality (p NS). When analyzing the last treatment and adjusting it for final SLEDAI, HCQ was a mortality protection factor (RR 0.4) while the use of cyclophosphamide alone or associated with prednisone was a risk factor for death (RR 5.2).

Significant differences were found when analyzing the causes of death according to the SLE evolution time (p 0.017): patients who died from infection had less evolution time (Me 2.25 years), than those who died due to cardiovascular causes (Me 10 years) or SLE activity (Me 15 years). In this cohort of patients, survival was 93% at 5 years, 88% at 10 years and 72% at 20 years.

Conclusion:

Mortality in this series of patients was 12% and infection was the leading cause of death. The use of HCQ for a period greater than 36 months, decreased the risk of death 40%.

Disclosure of Interests:

None declared

FRI0606-HPR REMISSION IN SYSTEMIC LUPUS ERYTHEMATOSUS, WHAT IS THE IMPACT ON ACCUMULATED DAMAGE?

Background:

The objective of the treatment in rheumatic diseases is to achieved the remission or minimal disease activity of these patients. Previous studies in Systemic Lupus Erythematosus (SLE) showed that reaching remission had a positive impact on the prognosis of the disease.

Objectives:

To determine the frequency of remission in a cohort of patients with SLE.

To evaluate the effect of disease activity on accrual damage.

Methods:

A retrospective study was carried out from January 2010 to December 2018. Clinical records of patients with SLE (ACR criteria 1982/97) were reviewed considering baseline visit as the first clinical or control visit of 2010. For subsequent visits, data were collected annually until 2018. SLE activity was defined for each visit according to GLADEL´s definition: 1- Remission Without Treatment (RwT): SLEDAI 0, without prednisone or immunosuppressive drugs (IS); 2- Remission on Treatment (RoT): SLEDAI 0, prednisone up to 5mg/day or immunosuppressive drugs in maintenance doses; 3- LDAS (Low Disease Activity Status): SLEDAI ≤ 4, prednisone up to 7.5mg/ ay and/or IS in maintenance doses; 4- Non-Optimal Activity Control (NOC): SLEDAI> 4, prednisone> 7.5 mg/day and/or IS in induction dose. The use of hydroxychloroquine was allowed for all groups. For the analysis, patients who remained in remission (with and without treatment) or LDAS for at least 75% of the follow-up time were grouped and compared with patients who remained active during that same period. Demographic, laboratory, treatment related variables and death were studied. Accrual damage was assessed with SLICC / SDI. Patients with less than two annual visits were excluded.

Statistical analysis: descriptive measures, Test T, Mann Whitney, Chi2 Test, Fisher’s exact test, bivariate correlation, logistic regression model with mixed effects.

Results:

Two hundred eighty-five medical records were reviewed and 100 patients with SLE were included, 89% women, mean age at baseline visit 38.5 ± 12 years old and mean time of disease 9.3 ± 7.3 years. The average SLEDAI and SLICC/SDI baseline scores were 3.7 and 0.8 respectively. The SLICC/ SDI score at last visit was 2.2 and the average SLICC/SDI change (ΔSLICC) compared to baseline visit score was 1.4 ± 1.6.

The prevalence of patients who were in remission for at least 75% of the follow-up time was 38% [95% CI 26.6, 45.4]. NOC patients categorized at baseline visit had the highest ΔSLICC (p 0.0001). The ΔSLICC was significantly lower in patients who were at least 75% of the follow-up time in remission (p 0.01) or LDAS (p 0.01) compared to those with NOC. In the Logistic Regression Model, the chance of changing the SLICC/SDI score was 2.9 times higher for the NOC group than for RwT.

Conclusion:

The frequency of remission in this cohort of patients with SLE was 38%.

Worse control of disease activity, was associated with higher accumulated damage.

Disclosure of Interests:

None declared

FRI0602-HPR PERSISTENT HYPOCOMPLEMENTEMIA IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

Background:

Systemic lupus erythematosus (SLE) is a systemic, chronic, autoimmune disease of unknown cause characterized by a wide variety of clinical manifestations and autoantibody production. The complement is useful in the initial diagnosis, as an activity marker and for the follow-up of patients with SLE. Individual components may fluctuate only slightly with disease activity and C4 may even remain low during remission. Hypocomplementemia is associated with renal involvement, cutaneous vasculitis, diffuse alveolar hemorrhage, however, patients with persistent hypocomplementemia are not characterized yet.

Objectives:

1) Determine the prevalence of persistent hypocomplementemia in patients with SLE.

2) Identify clinical characteristics, disease activity and accumulated damage in these patients.

Methods:

A longitudinal study was conducted with a review of the medical records of patients diagnosed with SLE (ACR criteria 82/97) who attended the Rheumatology Service between January 2000 and December 2015. Patients with a minimum evolution time of 6 months from the diagnosis of SLE with quarterly controls and monitoring for 2 years. Persistent Hypocomplementemia (PHC) was defined at C3 and / or C4 values below the normal range of the reference laboratory in a sustained form for at least 24 months. Demographic variables, clinical manifestations, disease activity by SLEDAI 2k, flare by SELENA SLEDAI and accumulated damage by SLICC / SDI were analyzed.

Results:

Clinical records of 254 patients with SLE were reviewed and 144 were included; 96% were women, with a mean age at diagnosis of SLE of 30.5 ± 11.2 years and a time of evolution of the disease at the last control 11.85 ± 7.8 years. Forty-one patients had PHC (28.5%; 95% CI 21.1, 35.8). The median of evolution time disease at the moment of PHC was 1 year (0-24) and the mean time of persistence of hypocomplementemia was 56 ± 46 months. In the univariate analysis, PHC was associated with hematological involvement during the course of the disease (p=0.01). Patients with PHC had a higher frequency of severe flare during follow-up (p=0.02). PHC was not associated with age of onset of SLE, disease activity (maximum SLEDAI reached), accumulated damage or death. Applying Logistic Regression Model with dependent variables with a level of significance <0.25, PHC was associated independently with hematological compromise (OR 3.2).

Conclusion:

In this cohort of patients, the prevalence of PHC was 28.5%. PHC was associated with severe flare and hematological compromise.

Disclosure of Interests:

None declared

FRI0650-HPR SEXUAL DYSFUNCTION IN WOMEN WITH SYSTEMIC LUPUS ERYTHEMATOSUS

Background:

Sexual dysfunction is the alteration in one or several phases of sexual activity (desire, excitement, plateau, orgasm and resolution), which can culminate in frustration, pain and a decrease in the frequency of sexual intercourse. There are few studies that associate sexual dysfunction with Systemic Lupus Erythematosus (SLE) due to the difficulty in assessing it and its multifactorial cause.

Objectives:

Determine the frequency of sexual dysfunction and analyze associated factors in patients with SLE.

Methods:

A descriptive cross-sectional study was conducted. We included patients who attended the Rheumatology unit between May and July 2019; over 18 years of age, with a diagnosis of SLE according to the ACR 1997 and / or SLICC 2012 criteria, and healthy patients matched by age as control. Demographic and disease-related variables were studied. The DASS-21 (Depression Anxiety Stress Scale) scale that evaluates depression, anxiety and stress, and the Female Sexual Function Index (FSFI) that assesses 6 domains (desire, excitement, lubrication, orgasms, satisfaction and pain) were applied with a cut-off point ≤ 26.5 to define sexual dysfunction. Women over 50 years old, with secondary Sjogren’s syndrome, menopause, severe depression and illiterate patients were excluded.

Results:

One hundred and twenty three women were included (60 with SLE and 63 controls), with a mean age of 34.3 ± 8.3 and 31.7 ± 4.4 years respectively. The prevalence of sexual dysfunction in the SLE group was 71.7%; 95% CI = [58.5 – 82.5], and 23.8%, 95% CI = [13.9 – 36.2] in healthy patients. There were significant differences in all domains of sexual function between women with SLE and healthy group. In the desire, excitement and pain domains the differences were notable. The total FSFI score in patients with SLE was 18.2 ± 11.2 and in healthy women 28.3 ± 6.9 (p=0.001). Stress, anxiety and depression were observed in 58.4%, 58.3% and 50% of women with SLE and 19%, 20.6% and 28.5% of healthy women respectively (p=0.001). No association was found between sexual dysfunction and age, age at diagnosis, disease activity or treatment (pNS). No association was found in patients with SLE when analyzing the effect of sexual dysfunction in stress, depression and anxiety variables, in opposition to the healthy group (p<0.05).

Conclusion:

The prevalence of sexual dysfunction in patients with SLE was high (71.7%). Depression, Anxiety, and Stress were not decisive variables in Sexual Dysfunction.

Disclosure of Interests:

None declared

The entomopathogenic fungus Beauveria bassiana produces microsclerotia-like pellets mediated by oxidative stress and peroxisome biogenesis

Several filamentous fungi are known to produce macroscopic pigmented hyphal aggregates named sclerotia. In recent years, some entomopathogenic fungi were reported to produce small sclerotia termed 'microsclerotia', becoming new potential propagules for biocontrol strategies. In this study, we described the production of microsclerotia-like pellets by the entomopathogenic fungus Beauveria bassiana. The carbon: nitrogen ratio equal to or higher than 12.5:1 amended with Fe²⁺ induced the germination of conidia, producing hyphal aggregate that formed sclerotial structures in submerged liquid cultures. These aggregates were able to tolerate desiccation as they germinated and subsequently produced viable conidia. Conidia derived from microsclerotial aggregates formulated with diatomaceous earth effectively kill Tribolium castaneum larvae. Optical and transmission microscopical imaging, qPCR and spectrophotometric analysis revealed that an oxidative stress scenario is involved in conidial differentiation into microsclerotia-like pellets, inducing fungal antioxidant response with high peroxidase activity - mainly detected in peroxisomes and mitochondria - and progress with active peroxisome proliferation. The results provide clues about B. bassiana microsclerotial differentiation and indicate that these pigmented aggregates are promising propagules for production, formulation and potentially application in the control of soil-inhabiting arthropod pests.

Alkane-grown Beauveria bassiana produce mycelial pellets displaying peroxisome proliferation, oxidative stress, and cell surface alterations

The entomopathogenic fungus Beauveria bassiana is able to grow on insect cuticle hydrocarbons, inducing alkane assimilation pathways and concomitantly increasing virulence against insect hosts. In this study, we describe some physiological and molecular processes implicated in growth, nutritional stress response, and cellular alterations found in alkane-grown fungi. The fungal cytology was investigated using light and transmission electron microscopy while the surface topography was examined using atomic force microscopy. Additionally, the expression pattern of several genes associated with oxidative stress, peroxisome biogenesis, and hydrophobicity were analysed by qPCR. We found a novel type of growth in alkane-cultured B. bassiana similar to mycelial pellets described in other alkane-free fungi, which were able to produce viable conidia and to be pathogenic against larvae of the beetles Tenebrio molitor and Tribolium castaneum. Mycelial pellets were formed by hyphae cumulates with high peroxidase activity, exhibiting peroxisome proliferation and an apparent surface thickening. Alkane-grown conidia appeared to be more hydrophobic and cell surfaces displayed different topography than glucose-grown cells. We also found a significant induction in several genes encoding for peroxins, catalases, superoxide dismutases, and hydrophobins. These results show that both morphological and metabolic changes are triggered in mycelial pellets derived from alkane-grown B. bassiana.

Biochemical and structural characterization of a novel arginine kinase from the spider Polybetes pythagoricus

Energy buffering systems are key for homeostasis during variations in energy supply. Spiders are the most important predators for insects and therefore key in terrestrial ecosystems. From biomedical interest, spiders are important for their venoms and as a source of potent allergens, such as arginine kinase (AK, EC 2.7.3.3). AK is an enzyme crucial for energy metabolism, keeping the pool of phosphagens in invertebrates, and also an allergen for humans. In this work, we studied AK from the Argentininan spider Polybetes pythagoricus (PpAK), from its complementary DNA to the crystal structure. The PpAK cDNA from muscle was cloned, and it is comprised of 1068 nucleotides that encode a 384-amino acids protein, similar to other invertebrate AKs. The apparent Michaelis-Menten kinetic constant (K_m) was 1.7 mM with a k_cat of 75 s⁻¹. Two crystal structures are presented, the apoPvAK and PpAK bound to arginine, both in the open conformation with the active site lid (residues 310–320) completely disordered. The guanidino group binding site in the apo structure appears to be organized to accept the arginine substrate. Finally, these results contribute to knowledge of mechanistic details of the function of arginine kinase.

Room Temperature Crystallization of Hydroxyapatite in Porous Silicon Structures

Porous silicon (PS) substrates, with different pore sizes and morphology, have been used to crystallize hydroxyapatite (HA) nano-fibers by an easy and economical procedure using a co-precipitation method at room temperature. In situ formation of HA nanoparticles, within the meso- and macroporous silicon structure, resulted in the formation of nanometer-sized hydroxyapatite crystals on/within the porous structure. The X-ray diffraction technique was used to determine the tetragonal structure of the crystals. Analysis/characterization demonstrates that under certain synthesis conditions, growth and crystallization of hydroxyapatite layer on/inside PS can be achieved at room temperature. Such composite structures expand the possibility of designing a new bio-composite material based on the hydroxyapatite and silicon synthesized at room temperature.

Validation of an Argentine version of Lupus Quality of Life questionnaire

OBJECTIVE

To determine reproducibility and validity of an Argentine version of the Lupus Quality of Life questionnaire (LupusQoL) and to determine cut-off values in the questionnaire.

MATERIALS AND METHODS

One hundred and forty-seven systemic lupus erythematosus patients (American College of Rheumatology 1982/1997) were assessed from April 2014 to July 2014. Demographic and socioeconomic variables were collected, as well as SELENA/SLEDAI, Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index Score, comorbidities and treatment data. Patients completed LupusQoL-Argentine version and European Quality of Life Questionnaire (EuroQoL-5D). Internal consistency and reliability were examined. Convergent validity with EuroQoL-5D was assessed through analysis of latent classes, which established homogeneous categories from the responses of each domain of LupusQoL and for the total.

RESULTS

Out of 147 patients, 93.2% were female, mean age 36.4 ± 11.1 years, mean disease duration 2.7 ± 9 years, mean SELENA/SLEDAI 2.7 ± 3 points. The cut-off point that defined good or bad quality of life was 0.739 for EuroQoL 5D and 63 for LupusQoL. Cut-off values for each LupusQoL domain were also defined, creating two classes in each of them. There was moderate to high concordance to classify quality of life (Kappa = 0.74, 95% confidence interval = 0.54, 0.95).

CONCLUSION

The Argentine version of LupusQoL is a valid, reliable and reproducible instrument to assess quality of life. In this study, cut-off points that allow the classification of patients regarding whether they have good or bad quality of life are established for the first time.

Different expression patterns of LGALS1 and LGALS3 in polycythemia vera, essential thrombocythemia and primary myelofibrosis

Despite all the knowledge, the cellular and molecular mechanisms involved in myeloproliferative neoplasm (MPN) pathophysiology remain unclear. Authors have shown galectin-1 (Gal-1) and 3 playing roles in tumour angiogenesis and fibrosis, which were correlated with poor prognosis in patients with MPN. In the present study LGALS1 and LGALS3 were differently expressed between polycythemia vera, essential thrombocythemia (ET) and primary myelofibrosis (PMF) diseases. Increased LGALS3 expression was associated with a negative JAK2 V617F status mutation in leucocytes from PMF but not in patients with ET without this mutation. However, a positive Janus kinase 2 (JAK2) V617F cell line established from patients with ET (SET-2 cells) when treated with JAK inhibitor presented high levels of LGALS3. Additionally, high LGALS1 expression was found in CD34(+) cells but not in leucocytes from patients with PMF, in absence of JAK2 V617F mutation, and also in SET-2 cells treated with JAK inhibitor. Thus, our findings indicate that differential expression of LGALS1 and/or LGALS3 in patients with MPN is linked with JAK2 V617F status mutation in these diseases and state of cell differentiation.

Saddle antenna radio frequency ion sources

Existing RF ion sources for accelerators have specific efficiencies for H(+) and H(-) ion generation ∼3-5 mA/cm(2) kW, where about 50 kW of RF power is typically needed for 50 mA beam current production. The Saddle Antenna (SA) surface plasma source (SPS) described here was developed to improve H(-) ion production efficiency, reliability, and availability. In SA RF ion source, the efficiency of positive ion generation in the plasma has been improved to 200 mA/cm(2) kW. After cesiation, the current of negative ions to the collector was increased from 1 mA to 10 mA with RF power ∼1.5 kW in the plasma (6 mm diameter emission aperture) and up to 30 mA with ∼4 kW RF. Continuous wave (CW) operation of the SA SPS has been tested on the test stand. The general design of the CW SA SPS is based on the pulsed version. Some modifications were made to improve the cooling and cesiation stability. CW operation with negative ion extraction was tested with RF power up to ∼1.2 kW in the plasma with production up to Ic = 7 mA. A stable long time generation of H(-) beam without degradation was demonstrated in RF discharge with AlN discharge chamber.

Characterization of the CW starter plasma RF matching network for operating the SNS H⁻ ion source with lower H₂ flows

The Spallation Neutron Source H(-) ion source is operated with a pulsed 2-MHz RF (50-60 kW) to produce the 1-ms long, ∼50 mA H(-) beams at 60 Hz. A continuous low power (∼300 W) 13.56-MHz RF plasma, which is initially ignited with a H2 pressure bump, serves as starter plasma for the pulsed high power 2-MHz RF discharges. To reduce the risk of plasma outages at lower H2 flow rates which is desired for improved performance of the following radio frequency quadrupole, the 13.56-MHz RF matching network was characterized over a broad range of its two tuning capacitors. The H-α line intensity of the 13.56-MHz RF plasma and the reflected power of the 13.56-MHz RF were mapped against the capacitor settings. Optimal tunes for the maximum H-α intensity are consistent with the optimal tunes for minimum reflected power. Low limits of the H2 flow rate not causing plasma outages were explored within the range of the map. A tune region that allows lower H2 flow rate has been identified, which differs from the optimal tune for global minimum reflected power that was mostly used in the past.

The status of the SNS external antenna ion source and spare RFQ test facility

The Oak Ridge National Laboratory operates the Spallation Neutron Source, consisting of a H(-) ion source, a 1 GeV linac and an accumulator ring. The accumulated <1 μs-long, ∼35 A beam pulses are extracted from the ring at 60 Hz and directed onto a liquid Hg target. Spalled neutrons are directed to ∼20 world class instruments. Currently, the facility operates routinely with ∼1.2 MW of average beam power, which soon will be raised to 1.4 MW. A future upgrade with a second target station calls for raising the power to 2.8 MW. This paper describes the status of two accelerator components expected to play important roles in achieving these goals: a recently acquired RFQ accelerator and the external antenna ion source. Currently, the RFQ is being conditioned in a newly constructed 2.5 MeV Integrated Test Facility (ITF) and the external antenna source is also being tested on a separate test stand. This paper presents the results of experiments and the testing of these systems.

Recent performance of and plasma outage studies with the SNS H⁻ source

Spallation Neutron Source ramps to higher power levels that can be sustained with high availability. The goal is 1.4 MW despite a compromised radio frequency quadrupole (RFQ), which requires higher radio frequency power than design levels to approach the nominal beam transmission. Unfortunately at higher power the RFQ often loses its thermal stability, a problem apparently enhanced by beam losses and high influxes of hydrogen. Delivering as much H(-) beam as possible with the least amount of hydrogen led to plasma outages. The root cause is the dense 1-ms long ∼55-kW 2-MHz plasma pulses reflecting ∼90% of the continuous ∼300 W, 13-MHz power, which was mitigated with a 4-ms filter for the reflected power signal and an outage resistant, slightly detuned 13-MHz match. Lowering the H2 gas also increased the H(-) beam current to ∼55 mA and increased the RFQ transmission by ∼7% (relative).

Neonatal viability evaluation by Apgar score in puppies delivered by cesarean section in two brachycephalic breeds (English and French bulldog)

This study tried to define neonatal viability after cesarean section in brachycephalic breeds and the efficacy of an adapted Apgar test to assess newborn survival. Data from 44 cesarean sections and 302 puppies were included. Before surgery (59-61 days after ovulation), an ultrasound evaluation defined the fetal biparietal diameter (BPD). Immediately after the uterine delivery, the pups were evaluated to detect birth defects and then, a modified Apgar score (range: 0-10) was used to define neonatal health at 5min (Apgar 1) and 60min (Apgar 2) after neonatal delivery; puppies were classified into three categories: critical neonates (score: 0-3), moderate viability neonates (score: 4-6) and normal viability neonates (score: 7-10). Mean (±SEM) value of BPD was 30.8±0.1mm and 28.9±0.1mm in English and French Bull-Dog fetus, respectively. The incidence of spontaneous neonatal mortality (4.98%, 14/281) and birth defects (6.95%) were not influenced by the sex; however, congenital anomalies and neonatal mortality were higher (p<0.01) in those litters with a greater number of neonates. In Apgar 1, the percentage of critical neonates, moderate viability neonates and normal viability neonates were 20.5%, 46.3% and 33.1% respectively; sixty minutes after birth, the critical neonates only represented 10.3% of the total puppies. Almost all neonates (238/239) showing moderate or normal viability at Apgar 1, survived for the first 24h after birth. The results of the study showed a direct relationship (p<0.01) between the Apgar score and neonatal viability. Therefore, the routine performance of the Apgar score would appear to be essential in the assessment of the status of brachycephalic breed puppies.

Improving efficiency of negative ion production in ion source with saddle antenna

Extraction of negative ions from a saddle antenna radio-frequency surface plasma source is considered. Several versions of new plasma generators with different antennas and magnetic field configurations were tested in the smal Oak Ridge National Laboratory Spallation Neutron Source Test Stand. The efficiency of positive ion generation in plasma has been improved to 200 mA/cm(2) kW from 2.5 mA/cm(2) kW. A small oven was developed for cesiation by cesium compounds and alloy decomposition. After cesiation, a current of negative ions to the collector was increased from 1 mA to 10 mA with 1.5 kW RF power in the plasma and longitudinal magnetic field Bl ∼ 250 G. The specific efficiency of H(-) production was increased to 20 mA/cm(2) kW from 2.5 mA/cm(2) kW.

Plasma emission spectroscopy for operating and developing the Spallation Neutron Source (SNS) H(-) ion sources

A RF-driven, Cs-enhanced H(-) ion source feeds the SNS accelerator with a high current (typically >50 mA), ∼1.0 ms pulsed beam at 60 Hz. To achieve the persistent high current beam for several weeks long service cycles, each newly installed ion source undergoes a rigorous conditioning and cesiation processes. Plasma conditioning outgases the system and sputter-cleans the ion conversion surfaces. A cesiation process immediately following the plasma conditioning releases Cs to provide coverage on the ion conversion surfaces. The effectiveness of the ion source conditioning and cesiation is monitored with plasma emission spectroscopy using a high-sensitivity optical spectrometer. Plasma emission spectroscopy is also used to provide a means for diagnosing and confirming a failure of the insulating coating of the ion source RF antenna which is immersed in the plasma. Emissions of composition elements of the antenna coating material, Na emission being the most significant, drastically elevate to signal a failure when it happens. Plasma spectra of the developmental ion source with an AlN (aluminum nitrite) chamber and an external RF antenna are also briefly discussed.

Recent performance of the SNS H(-) ion source and low-energy beam transport system

Recent measurements of the H(-) beam current show that SNS is injecting about 55 mA into the RFQ compared to ∼45 mA in 2010. Since 2010, the H(-) beam exiting the RFQ dropped from ∼40 mA to ∼34 mA, which is sufficient for 1 MW of beam power. To minimize the impact of the RFQ degradation, the service cycle of the best performing source was extended to 6 weeks. The only degradation is fluctuations in the electron dump voltage towards the end of some service cycles, a problem that is being investigated. Very recently, the RFQ was retuned, which partly restored its transmission. In addition, the electrostatic low-energy beam transport system was reengineered to double its heat sinking and equipped with a thermocouple that monitors the temperature of the ground electrode between the two Einzel lenses. The recorded data show that emissions from the source at high voltage dominate the heat load. Emissions from the partly Cs-covered first lens cause the temperature to peak several hours after starting up. On rare occasions, the temperature can also peak due to corona discharges between the center ground electrode and one of the lenses.

Improvements to the internal and external antenna H(-) ion sources at the Spallation Neutron Source

The Spallation Neutron Source (SNS), a large scale neutron production facility, routinely operates with 30-40 mA peak current in the linac. Recent measurements have shown that our RF-driven internal antenna, Cs-enhanced, multi-cusp ion sources injects ∼55 mA of H(-) beam current (∼1 ms, 60 Hz) at 65-kV into a Radio Frequency Quadrupole (RFQ) accelerator through a closely coupled electrostatic Low-Energy Beam Transport system. Over the last several years a decrease in RFQ transmission and issues with internal antennas has stimulated source development at the SNS both for the internal and external antenna ion sources. This report discusses progress in improving internal antenna reliability, H(-) yield improvements which resulted from modifications to the outlet aperture assembly (applicable to both internal and external antenna sources) and studies made of the long standing problem of beam persistence with the external antenna source. The current status of the external antenna ion source will also be presented.

Influence of cool storage before freezing on the quality of frozen-thawed semen samples in dogs

The aim of this study was to determinate the semen quality of frozen-thawed samples that were chilled for up to 2 days before freezing. The ejaculates (n = 18) from six dogs were collected, pooled and divided into six aliquots. The first aliquot (C, control) was frozen in liquid nitrogen using a conventional protocol to reach a final concentration of 100 × 10(6) spermatozoa/ml, 20% egg yolk and 5% glycerol. The remaining five aliquots were diluted with a chilled extender (Tris-glucose and 20% egg yolk) and cooled at 4 °C as follows: R1, the semen was cooled for 1 h; R6, the semen was cooled for 6 h; R12, the semen was cooled for 12 h; R24, the semen was cooled for 24 h and R48, the semen was cooled for 48 h. After the chilling period, a second extender was added (Tris-glucose, 20% egg yolk, 10% glycerol and Equex at 1%) to reach a final composition similar to aliquot C, and then, the semen samples (R1, R6, R12, R24 and R48) were frozen in liquid nitrogen. The post-thaw sperm quality was assessed in 30 straws from each experimental group. After freezing-thawing, the total sperm motility (approximately 60-70%) in the semen chilled for up to 48 h did not show any differences from the samples frozen by the conventional cryopreservation method (63.2%). No significant differences were detected in the percentages of abnormal sperm cells among the fresh semen, the control group and the frozen samples after the different cooling times. Finally, the post-thaw percentages of damaged acrosomes showed a very uniform distribution, with mean values ranging between 7% and 10.5%. The results clearly demonstrated that cooling the semen up to 48 h before freezing did not produce a decrease in the semen quality when was compared with semen frozen by a traditional procedure.

H- radio frequency source development at the Spallation Neutron Source

The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent ∼38 mA peak current in the linac and an availability of ∼90%. H(-) beam pulses (∼1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, ∼60 kW) of a copper antenna that has been encased with a thickness of ∼0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of ∼99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of ∼75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance∕installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to ∼100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

Surface plasma source with saddle antenna radio frequency plasma generator

A prototype RF H(-) surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA∕kW. Control experiments with H(-) beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing.

Producing persistent, high-current, high-duty-factor H- beams for routine 1 MW operation of Spallation Neutron Source (invited)

Since 2009, the Spallation Neutron Source (SNS) has been producing neutrons with ion beam powers near 1 MW, which requires the extraction of ∼50 mA H(-) ions from the ion source with a ∼5% duty factor. The 50 mA are achieved after an initial dose of ∼3 mg of Cs and heating the Cs collar to ∼170 °C. The 50 mA normally persist for the entire 4-week source service cycles. Fundamental processes are reviewed to elucidate the persistence of the SNS H(-) beams without a steady feed of Cs and why the Cs collar temperature may have to be kept near 170 °C.

Low-energy beam transport studies supporting the spallation neutron source 1-MW beam operation

The H(-) injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the spallation neutron source 1 MW beam operation with ∼38 mA beam current in the linac at 60 Hz with a pulse length of up to ∼1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: (1) inconsistent dependence of the post-radio frequency quadrupole accelerator beam current on the ion source tilt angle and (2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

Sperm viability of canine and caprine semen samples preserved in a dry shipper

This study assessed the efficacy of a dry shipper to preserve canine and caprine semen samples. After equilibration, semen straws from six Majorera bucks and five dogs were frozen and stored in liquid nitrogen (LN). Thirty days after freezing, half of the frozen straws were transferred from LN to a dry shipper (DS). Then, thawing was performed at 1, 2, 3, 5 and 7 days and the percentages of motile spermatozoa, acrosome intact spermatozoa and abnormal spermatozoa were determined. The sperm motility (total and progressive) of canine semen samples preserved with DS was quite similar to those preserved in LN, and no significant differences were observed throughout the experimental period. In addition, no differences were observed in the number of abnormal spermatozoa (range: 13.2-19.0%) or intact acrosome (range 91.3-95%) between both storage protocols. Buck semen samples showed equivalent levels of progressive motility (between 50% and 60%) and intact acrosome membrane (around 70%) during the first 3 days of storage in both procedures; however, from the fifth day of storage onwards, a notable decrease in semen quality was observed in the samples preserved in DS, showing a dramatic fall in the semen viability after 7 days of preservation (12.3% and 36.8%, progressive fast spermatozoa and acrosome integrity, respectively). In dog samples, the present study confirmed that seminal quality did not show modifications for the preservation period (7 days), confirming the efficacy of the dry shipper to preserve frozen samples for a short time. However, under the circumstances reported in this study, the sperm quality of buck samples preserved in the dry shipper only held during the first 3 days of storage, and therefore, its practical application could be more limited.

Presence and potential role of thermophilic bacteria in temperate terrestrial environments

Organic sulfur and nitrogen are major reservoirs of these elements in terrestrial systems, although their cycling remains to be fully understood. Both sulfur and nitrogen mineralization are directly related to microbial metabolism. Mesophiles and thermophiles were isolated from temperate environments. Thermophilic isolates were classified within the Firmicutes, belonging to the Geobacillus, Brevibacillus, and Ureibacillus genera, and showed optimum growth temperatures between 50°C and 60°C. Sulfate and ammonium produced were higher during growth of thermophiles both for isolated strains and natural bacterial assemblages. They were positively related to organic nutrient load. Temperature also affected the release of sulfate and ammonium by thermophiles. Quantitative, real-time reverse-transcription polymerase chain reaction on environmental samples indicated that the examined thermophilic Firmicutes represented up to 3.4% of the total bacterial community RNA. Temperature measurements during summer days showed values above 40°C for more than 10 h a day in soils from southern Spain. These results support a potential role of thermophilic bacteria in temperate terrestrial environments by mineralizing organic sulfur and nitrogen ruled by the existence and length of warm periods.

Exuberant mucometra associated with atresia of the cervix in a queen

This short communication reports the clinical, ultrasonographic and histopathological findings in a cat with atresia of the uterine cervix and mucometra. After 6 months of continuous oestrous behaviour, a remarkable abdominal enlargement was observed in a 14-year-old queen. A presumptive diagnosis of mucometra was concluded after the ultrasound evaluation and based on clinical signs and blood analyses. Ovariohysterectomy revealed a notable symmetrical distension (4-5 cm in diameter) of both uterine horns that were filled with fluid (690 ml); microbiological analyses confirmed the aseptic nature of the uterine fluid. Ovarian follicular cysts and cystic subsurface epithelial structures, >1.5 cm in diameter, were present in both ovaries and no corpora lutea were observed. Gross and microscopic evaluation of the uterus confirmed the development of cystic endometrial hyperplasia and the absence of an internal cervical os. The endometrial hyperplasia and mucometra could have developed as a consequence of repeated oestrogenic stimulation.

Influence of sexual stimulation and the administration of human chorionic gonadotrophin on plasma testosterone levels in dogs

The influence of sexual stimulation and human chorionic gonadotrophin (hCG) administration on plasma testosterone concentrations was assessed in five male Beagles. Each dog was exposed to three experimental treatments: C treatment (Control, no stimulation), hCG treatment (dogs were SC injected with 1000 IU of hCG) and sexually stimulated (SS) treatment where semen was collected from the males. All dogs were exposed to all treatments, one per week for three consecutive weeks, with a 1 week of rest between treatments. Blood samples were taken with the same time intervals (0, 10, 30, 60 and 120 min) relative to treatments. Plasma testosterone concentrations were determined with a solid-phase I(125) radioimmunoassay. In the control treatment, the testosterone plasma levels did not show significant changes throughout the tested period (mean values ranging between 2.8 and 4.7 ng/ml); the hCG group presented a significant increase (p < 0.05) in plasma testosterone levels 30 min after hCG administration and had the highest value (8.7 ng/ml) at 120 min post-hCG. Finally, the SS group revealed a slight reduction in testosterone concentration immediately after ejaculation, but the values remained nearly unaltered until 120 min after semen collection. When the groups were compared, the hCG group showed higher plasma testosterone values (p < 0.05) than did the C and SS groups, starting at 30 min and continuing until the end of sampling. This study demonstrates that sexual stimulation associated with semen collection does not produce transitory modifications in plasma testosterone concentrations.

Influence of the preservation temperature (37, 20, 4, -196°C) and the mixing of semen over sperm quality of Majorera bucks

This study assessed the effect of different semen storage temperatures and the influence of semen pooling in semen viability. In experiment 1, semen samples (n = 30) of five Majorera bucks were individually processed [Individual semen (IS)] and after the first dilution (Tris-yolk extender), semen-diluted aliquots from each male were pooled semen (PS). Thereafter, semen samples (IS and PS) were preserved as fresh semen (37 and 20°C), chilled semen (4°C) and frozen semen. Sperm motility and the percentage of abnormal sperm cells and intact membrane acrosomes were defined. Semen preservation at 20 and 4°C did not modify the quality of spermatozoa for the first 24 h, but the conservation at 37°C caused a dramatic fall in the semen motility from 12 h onwards. Furthermore, the longevity of frozen-thawed semen was limited to 4-6 h. No differences were observed in semen parameters when PS was compared with semen from individual males in any of the preservation protocols assessed. In experiment 2, 120 goats were distributed in four experimental groups: in group fresh individual semen (FIS, n = 30) and group frozen-thawed individual semen (FTIS, n = 30), does were transcervically inseminated with fresh semen and frozen-thawed semen from each individual male, respectively, and in group fresh pooled semen (FPS, n = 30) and group frozen-thawed pooled semen (FTPS, n = 30), goats were transcervically inseminated with FPS and FTPS, respectively. The kidding rate was very close in the FIS and FPS groups (70.0% and 73.7%, respectively), and no significant differences were observed in the fertility rate between FTIS and FTPS. The results of this study confirmed that semen samples may be preserved satisfactorily for 24 h both at 20 and 4°C. In addition, the mixture of semen of different bucks did not significantly modify the semen parameters when compared with semen from individual males.

Bilateral epididymal sperm granulomas following urethrostomy in a German shepherd dog

Bilateral enlargement of both epididymes was observed in a 6-year-old German shepherd dog following a pre-scrotal urethrostomy. Testicular parenchyma showed regular structure, and the spermatogenesis and the steroidogenic functions were not modified. However, macroscopic examination of the tail and the body of both epididymes exhibited multiple white and well-delimited foci. Histopathological study of the epididymes confirmed the development of granulomas associated with extravasated spermatozoa. Urethrostomy caused a severe stenosis of the penile urethra, favouring the retention of urine at the urinary bladder. The retrograde pressure exerted by the distension of the urinary bladder could have allowed the urine to reach the prostatic urethra and the deferent ducts and, finally, the epididymes, causing irritation and rupture of the mucous layer of the epididymal duct, the consequent sperm extravasation and the development of sperm granulomas. We speculate that the inadequate surgical resolution of the urethral calculi caused the bladder distension, the subsequent retrograde flow of urine and the development of the lesions.