Inducing a topological transition in graphene nanoribbon superlattices by external strain.

Armchair graphene nanoribbons, when forming a superlattice, can be classified into different topological phases, with or without edge states. By means of tight-binding and classical molecular dynamics (MD) simulations, we studied the electronic and mechanical properties of some of these superlattices. MD shows that fracture in modulated superlattices is brittle, as for unmodulated ribbons, and occurs at the thinner regions, with staggered superlattices achieving a larger fracture strain than inline superlattices. We found a general mechanism to induce a topological transition with strain, related to the electronic properties of each segment of the superlattice, and by studying the sublattice polarization we were able to characterize the transition and the response of these states to the strain. For the cases studied in detail here, the topological transition occurred at ∼3-5% strain, well below the fracture strain. The topological states of the superlattice - if present - are robust to strain even close to fracture. The topological transition was characterized by means of the sublattice polarization of the states.

[The experience of medical students as peer tutors]. / Rol de tutor par: experiencia de estudiantes de medicina.

BACKGROUND: Peer tutoring is a process of accompaniment carried out by a student with certain features and skills, whose objective is to support and guide, academically and emotionally, other students who may require it. AIM: To assess the experience of medical students who played the role of peer tutor. MATERIAL AND METHODS: We carried out semi-structured in-depth interviews, with prior informed consent, to a non-probabilistic and intentional sample of six students who performed the role of peer tutor, during 2017 and 2018. The data analysis followed the scheme of constant comparison and progressive reduction in a manual way, according to the comparative method, guaranteeing scientific rigor, maintaining criteria of credibility, dependence, confirmability, and transferability. RESULTS: The first level identified 234 units of meaning that originated in the third level, two qualitative domains, oriented to the contribution of peer tutors derived from their experience to strengthen both the process of peer tutor training and the management of peer tutoring. CONCLUSIONS: Peer tutoring as a teaching-learning strategy contributes to the development of generic competences and metacognitive skills, generating high levels of personal satisfaction and identification their teaching role.

Late development of pustular, erosive lesions in the muzzle of calves inoculated with Pseudocowpox virus.

We studied the pathogenesis of Pseudocowpox virus (PCPV), a zoonotic parapoxvirus associated with mucocutaneous lesions in cattle. Inoculation of calves with PCPV isolate SD 76-65 intranasally (n = 6) or transdermally in the muzzle (n = 2) resulted in virus replication and shedding up to day 13 post-infection (pi). No local or systemic signs were observed in inoculated calves up to day 20pi, when the clinical monitoring was discontinued. However, from days 28-34 pi, seven (7/8) inoculated calves underwent an asynchronous clinical course characterized by development of a few (one or two) to countless papulo-pustular, erosive-fibrinous and scabby lesions in the muzzle, in some cases extending to the lips and gingiva. In some animals, the lesions coalesced, forming extensive fibrinotic/necrotic and scabby plaques covering almost entirely the muzzle. The clinical course lasted 8-15 days and spontaneously subsided after day 42pi. Infectious virus and/or viral DNA were detected in swabs collected from lesions of 5/8 animals between days 34 and 42pi. Histological examination of fragments collected from the muzzle lesions of two affected calves (day 36pi) revealed marked epidermal hyperplasia and severe orthokeratotic and parakeratotic hyperkeratosis, covered by thick scabs. The epidermis showed multifocal areas of keratinocyte coalescing necrosis and mild multifocal vacuolar degeneration. Sera of inoculated calves at 50pi showed partial virus neutralization at low dilutions, demonstrating seroconversion. The delayed and severe clinical course associated with virus persistence in lesions are novel findings and contribute for the understanding of PCPV pathogenesis.

Thy1 (CD90) expression is regulated by DNA methylation during adipogenesis.

The obesity epidemic is developing into the most costly health problem facing the world. Obesity, characterized by excessive adipogenesis and enlarged adipocytes, promotes morbidities, such as diabetes, cardiovascular disease, and cancer. Regulation of adipogenesis is critical to our understanding of how fat cell formation causes obesity and associated health problems. Thy1 (also called CD90), a widely used stem cell marker, blocks adipogenesis and reduces lipid accumulation. Thy1-knockout mice are prone to diet-induced obesity. Although the importance of Thy1 in adipogenesis and obesity is now evident, how its expression is regulated is not. We hypothesized that DNA methylation has a role in promoting adipogenesis and affects Thy1 expression. Using the methylation inhibitor 5-aza-2'-deoxycytidine (5-aza-dC), we investigated whether DNA methylation alters Thy1 expression during adipogenesis in both mouse 3T3-L1 preadipocytes and mouse mesenchymal stem cells. Thy1 protein and mRNA levels were decreased dramatically during adipogenesis. However, 5-aza-dC treatment prevented that phenomenon. Methylation-sensitive pyrosequencing analysis showed that CpG sites at the Thy1 locus have increased methylation during adipogenesis, as well as increased methylation in adipose tissue from diet-induced obese mice. These new findings highlight the potential role of Thy1 and DNA methylation in adipogenesis and obesity.-Flores, E. M., Woeller, C. F., Falsetta, M. L., Susiarjo, M., Phipps, R. P. Thy1 (CD90) expression is regulated by DNA methylation during adipogenesis.

An extensive field study reveals the circulation of new genetic variants of subtype 1a of bovine viral diarrhea virus in Uruguay.

Bovine viral diarrhea virus (BVDV) is a major pathogen worldwide, causing significant economic losses to the livestock sector. In Uruguay, BVDV seroprevalence at the farm level is >80%. In this work, 2546 serum, blood or tissue samples collected from animals suspected of being affected by BVD between 2015 and 2017 were analyzed by reverse transcription PCR and sequencing. Analysis of the BVDV genomic regions 5'UTR/Npro, Npro and E2 revealed that BVDV-1a, 1i and 2b circulate in the country, with BVDV-1a being the most prevalent subtype. Population dynamics studies revealed that BVDV-1a has been circulating in our herds since ~1990. This subtype began to spread and evolve, accumulating point mutations at a rate of 3.48 × 10-3 substitutions/site/year, acquiring specific genetic characteristics that gave rise to two local genetic lineages of BVDV-1a. These lineages are divergent from those circulating worldwide, as well as the vaccine strain currently used in Uruguay. The most notable differences between field and vaccine strains were found in the E2 glycoprotein, suggesting that the amino acid substitutions could result in failure of cross-protection/neutralization after vaccination. This is the first study that compares Uruguayan BVDV field and vaccine strains with other BVDV strains from throughout the world. The results obtained in this study will be very useful for developing a suitable immunization program for BVDV in Uruguay by identifying local field strains as candidates for vaccine development.

Survival, disease progression and prognostic factors in elderly patients with mycosis fungoides and Sézary syndrome: a retrospective analysis of 174 patients.

BACKGROUND: Advanced age at diagnosis is considered a poor prognostic factor in mycosis fungoides (MF) and Sézary syndrome (SS). OBJECTIVE: To evaluate the outcomes and prognostic factors in patients diagnosed at an advanced age (≥65 years) with MF/SS. METHODS: Survival, progression rates and various clinical and histopathological variables were studied in a group of 174 elderly patients diagnosed with MF/SS between 1992 and 2015 at a single referral cancer center in the United States. Kaplan-Meier estimates were used to determine survival and progression and Cox proportional hazards regression univariate and multivariate models were used to identify prognostic factors. RESULTS: Of 174 elderly patients, 76.4% were diagnosed with early-stage (clinical stages IA-IIA) and 23.6% with late-stage MF/SS (IIB-IV). Advanced age was associated with poor overall survival, but not with disease-specific survival (DSS) or progression-free survival (PFS). Gender, increasing clinical stage, T and B classifications, elevated lactate dehydrogenase (LDH) levels and development of large cell transformation (LCT) were significant predictors of poor survival or disease progression. Patients with early-stage MF and <10% total skin involvement (T1 classification) or patch-only disease (T1a/T2a) showed better PFS with no observed disease-specific mortality. Folliculotropic MF was associated with poor DSS in patients with early-stage disease. CONCLUSIONS: Older age at diagnosis of MF/SS does not predict worse disease-specific outcomes. Elderly patients with early-stage disease, specifically involving less than 10% of the skin surface with patches but without plaques or folliculotropism, have an excellent prognosis. However, the development of LCT is a strong prognostic indicator of poor survival in elderly patients with MF/SS.

Peri-operative delineation of non-melanoma skin cancer margins in vivo with handheld reflectance confocal microscopy and video-mosaicking.

BACKGROUND: The surgical removal of non-melanoma skin cancers (NMSCs) is guided by the pathologic examination of margins. However, the preparation of histopathology is time consuming, labour-intensive and requires separate laboratory infrastructure. Furthermore, when histopathology indicates positive margins, patients must return for re-excisions. Reflectance confocal microscopy (RCM) with a new video-mosaicking approach can noninvasively delineate margins directly on patients and potentially guide surgery in real-time, augmenting the traditional approaches of histopathology. OBJECTIVE: To assess a new peri-operative RCM video-mosaicking approach for comprehensive delineation of NMSC margins on patients in vivo. METHODS: Thirty-five patients undergoing Mohs micrographic surgery (MMS) in the Mohs surgery unit at Memorial Sloan Kettering Cancer Center, New York, NY were included in the study. RCM imaging was performed before and after the first staged excision by acquiring videos along the surgical margins (epidermal, peripheral and deep dermal) of each wound, which were subsequently processed into video-mosaics. Two RCM evaluators read and assessed video-mosaics, and subsequently compared to the corresponding Mohs frozen histopathology. RESULTS: Reflectance confocal microscopy videos and video-mosaics displayed acceptable imaging quality (resolution and contrast), pre-operatively in 32/35 (91%) NMSC lesions and intra-operatively in 29/35 lesions (83%). Pre-operative delineation of margins correlated with the histopathology in 32/35 (91%) lesions. Intra-operative delineation correlated in 10/14 (71%) lesions for the presence of residual tumour and in 18/21 (86%) lesions for absence. Sensitivity/specificity were 71%/86% and 86%/81% for two RCM video-mosaic evaluators, and overall agreement was 80% and 83% with histopathology, with moderate inter-evaluator agreement (k = 0.59, P ≤ 0.0002). CONCLUSIONS: Peri-operative RCM video-mosaicking of NMSC margins directly on patients may potentially guide surgery in real-time, serve as an adjunct to histopathology, reduce time spent in clinic and reduce the need for re-excisions. Further testing in larger studies is needed.

Histopathological Characteristics of the Orbicularis Oculi Muscle After Lower Blepharoplasty With or Without Myotomy.

Lower blepharoplasty is a challenging aesthetic procedure. Despite advances in clinical and neuroanatomical studies related to orbicularis oculi muscle innervation, no study has examined its histopathological aspects in different lower blepharoplasty procedures. This study aimed to assess changes in the pretarsal muscle complex in patients treated with transcutaneous lower blepharoplasty with orbicularis myotomy versus those treated with transconjunctival blepharoplasty without myotomy. METHODS: A total of 268 patients underwent blepharoplasty performed by a single surgeon: transcutaneous lower blepharoplasty in 112 (41.7%) and transconjunctival lower blepharoplasty with retroseptal access in 156 (58.2%). Subsequent minor blepharoplasty procedures were performed in 32 patients with lower pretarsal orbicularis oculi muscle biopsy. Connective tissue, fibrillar elastic system, nerves, blood vessels, fiber diameter, and sarcomeres were analyzed. RESULTS: Without myotomy: collagen, 9.46 ± 0.41%; elastin, 7.03 ± 0.62%; blood vessels, 4.25 ± 0.06%; nerves, 5.2 ± 0.55%; fiber diameter, 62 ± 8.0 µm; and sarcomere, 1.9 ± 0.11 µm. With myotomy: collagen, 19.02 ± 1.66%; elastin, 7.88 ± 1.10%; blood vessels, 5.13 ± 0.70%; nerves, 2.9 ± 0.48%; fiber diameter, 49 ± 6.5 µm; and sarcomere, 1.8 ± 0.17 µm. DISCUSSION: Excess endomysial connective tissue, particularly between muscle fibers, should be considered pathological. The pathological changes in the pretarsal muscle complex after blepharoplasty with myotomy may have resulted from innervation interruptions as well as vascularization blockages. CONCLUSIONS: Surgeries with myotomy caused significant changes in collagen, nerves, and muscle fiber diameter. These observations strongly suggest the superiority of a technique that preserves orbicularis oculi muscle integrity. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Post-operative morbidity and mortality of a cohort of steroid refractory acute severe ulcerative colitis: Nationwide multicenter study of the GETECCU ENEIDA Registry.

BACKGROUND: Despite the increased use of rescue medical therapies for steroid refractory acute severe ulcerative colitis, mortality related to this entity still remains high. We aimed to assess the mortality and morbidity related to colectomy and their predictive factors in steroid refractory acute severe ulcerative colitis, and to evaluate the changes in mortality rates, complications, indications of colectomy, and the use of rescue therapy over time. METHODS: We performed a multicenter observational study of patients with steroid refractory acute severe ulcerative colitis requiring colectomy, admitted to 23 Spanish hospitals included in the ENEIDA registry (GETECCU) from 1989 to 2014. Independent predictive factors of mortality were assessed by binary logistic regression analysis. Mortality along the study was calculated using the age-standardized rate. RESULTS: During the study period, 429 patients underwent colectomy, presenting an overall mortality rate of 6.3% (range, 0-30%). The main causes of death were infections and post-operative complications. Independent predictive factors of mortality were: age ≥50 years (OR 23.34; 95% CI: 6.46-84.311; p < 0.0001), undergoing surgery in a secondary care hospital (OR 3.07; 95% CI: 1.01-9.35; p = 0.047), and in an emergency setting (OR 10.47; 95% CI: 1.26-86.55; p = 0.029). Neither the use of rescue medical treatment nor the type of surgical technique used (laparoscopy vs. open laparotomy) influenced mortality. The proportion of patients undergoing surgery in an emergency setting decreased over time (p < 0.0001), whereas the use of rescue medical therapy prior to colectomy progressively increased (p > 0.001). CONCLUSIONS: The mortality rate related to colectomy in steroid refractory acute severe ulcerative colitis varies greatly among hospitals, reinforcing the need for a continuous audit to achieve quality standards. The increasing use of rescue therapy is not associated with a worse outcome and may contribute to reducing emergency surgical interventions and improve outcomes.

Respiratory signs, fever and lymphopenia in calves inoculated with Brazilian HoBi-like pestiviruses.

Hobi-like viruses (HobiPeV) comprise a novel, recently classified species of bovine pestiviruses, originally identified in commercial fetal bovine serum of Brazilian origin and, subsequently, isolated from diseased animals in several countries. Although frequently isolated from clinical cases, most HobiPeV isolates failed to reproduce overt disease in cattle upon experimental inoculation. Herein, we describe the outcome of experimental infection of four to six months-old seronegative calves with two Brazilian HobiPeV isolates. Calves inoculated intranasally with isolate SV478/07 developed viremia between days 2 and 9 post-inoculation (pi) and shed virus in nasal secretions up to day 11pi. These animals presented hyperthermia (day 7 to 10-11 pi) and lymphopenia from days 4 to 8pi. Clinically, all four calves developed varied degrees of apathy, anorexia, mild to moderate respiratory signs (nasal secretion, hyperemia), ocular discharge and pasty diarrhea in the days following virus inoculation. In contrast, calves inoculated with isolate SV757/15 presented only hyperthermia (days 3 to 10-11 pi) and lymphopenia (days 4-8 pi), without other apparent clinical signs. In these animals, viremia was detected up to day 9 pi and virus shedding in nasal secretions lasted up to day 12-14 pi. Both groups seroconverted to the inoculated viruses, developing virus neutralizing (VN) titers from 320 to 5120 at day 28pi. These results extend previous findings that experimental infections of calves with HobiPeV are predominantly mild, yet they also indicate that field isolates may differ in their ability to cause disease in susceptible animals.

Cerium-doped ß-Ni(OH)2 hexagon nanosheets: an effective photocatalyst for the degradation of the emerging water pollutant, naproxen.

Nickel hydroxide ß-Ni(OH)2 hexagonal nanosheets were synthetized via a hydrothermal exfoliation process. The practical microwave-assisted hydrothermal method facilitated obtaining layered nickel 3D nanoplates with cerium functionalization in 5 h. The as-produced nanostructures were characterized by XRD, XPS, FESEM, FTIR, PL, UV-vis, and BET techniques. The hydroxilated structures are nano-thick hexagonal plates with sides 28 nm in length and an average thickness of 5 nm. UV and PL irradiation was used to study the photoactive properties in the degradation of a pharmaceutical emerging pollutant, naproxen. UV-vis spectroscopy and high-performance liquid chromatography monitoring indicated that the Ni(OH)2-Ce nanostructures are an effective photocatalyst for naproxen degradation, including 40% mineralization of this highly recalcitrant drug. The photocatalyst showed stability for two consecutive cycles, preserving its photoactive and structural characteristics. Ce3+-doped nanoplates and surface functionalized Ce4+ act as charge separators and scavenging agents for the enhanced photodegradation of naproxen.

Skin temperature in youth soccer players with functional equinus and non-equinus condition after running.

OBJECTIVES: To check how a thermal IR camera can check skin temperature in gastrocnemius-soleus equinus condition and non-gastrocnemius-soleus condition in youth soccer players and thus detect association between the extensibility of the triceps surae (with gastrocnemius-soleus equinus and non-gastrocnemius-soleus equinus) and the muscle temperature pattern. DESIGN: A cross-sectional study secondary level of care. METHODS: Sample from an elite soccer academy in Madrid (Spain) 35 healthy male subjects (youth soccer players) age 12.82 ± 1.07 years, height 158.68 ± 10.79 cm, weight 49.19 ± 9.45 kg, body mass index 19.41 ± 2.25. The exclusion criteria were the presence of musculoskeletal and joint injuries, pelvic pain, ankle sprains, low back pain and use of drugs in the previous week, and scoliosis. RESULTS: Temperature value for gastrocnemius muscles and Achilles tendon were assessed in 35 youth soccer players from an academia before and after training in both 12 gastrocnemius-soleus equinus and 23 non-gastrocnemius-soleus equinus soccer players conditions. State absolute for gastrocnemius soleus condition obtained a 0.34 value (0.19-0.5); we found a significant increase in temperature among these conditions for the gastrocnemius (P = 0.028) and the Achilles tendon (P = 0.007) (confidence interval 95%). The temperature of gastrocnemius-soleus equinus for gastrocnemius and Achilles tendon was increased more than non-gastrocnemius-soleus equinus in youth soccer players. CONCLUSIONS: IR imaging captured temperature is associated with muscle pattern activation for lower limb. Based on our findings, we propose that infrared thermography evaluation of the gastrocnemius and Achilles tendon is suitable to differ gastrocnemius-soleus equinus and non-gastrocnemius-soleus equinus conditions in youth soccer players.

Peptoanaerobacter stomatis Primes Human Neutrophils and Induces Granule Exocytosis.

Peptoanaerobacter stomatis is a newly appreciated taxon associated with periodontal diseases; however, little is known about the organism's pathogenic potential or its interaction with the host immune response. Neutrophils are the most abundant innate immune cell present in the gingival tissue and function to constrain the oral microbial challenge. However, some periodontal pathogens have developed strategies to evade phagocytosis and killing by neutrophils. Therefore, to begin to understand the role of P. stomatis in periodontitis, we studied its interactions with human neutrophils. Our data showed that after 30 min of incubation, neutrophils failed to engulf P. stomatis efficiently; however, when P. stomatis was internalized, it was promptly eradicated. P. stomatis challenge induced a robust intracellular respiratory burst; however, this response did not contribute to bacterial killing. Minimal superoxide release was observed by direct bacterial challenge; however, P. stomatis significantly increased N-formyl-methionyl-leucyl phenylalanine (fMLF)-stimulated superoxide release to an extent similar to that of cells primed with tumor necrosis factor alpha (TNF-α). When neutrophils were challenged with P. stomatis, 52% of the bacterium-containing phagosomes were enriched for the specific granule marker lactoferrin and 82% with the azurophil granule marker elastase. P. stomatis challenge stimulated exocytosis of the four neutrophil granule subtypes. Moreover, P. stomatis susceptibility to extracellular killing could be attributed to the exocytosis of antimicrobial components present in neutrophil granules. Priming neutrophils for an enhanced respiratory burst together with promoting granule content release could contribute to the chronic inflammation and tissue destruction that characterize periodontal diseases.

Multitechnique Determination of Halogens in Soil after Selective Volatilization Using Microwave-Induced Combustion.

A method for digestion of soils with high inorganic matter content (ranging from 50 to 92%) by microwave-induced combustion (MIC) is proposed for the first time for further halogens (F, Cl, Br, and I) determination by ion chromatography (IC) and also by inductively coupled plasma mass spectrometry (ICP-MS). Microcrystalline cellulose (100-500 mg), used as a combustion aid, was mixed with sample and water or NH4OH solutions (10-100 mmol L-1) were investigated for analytes absorption. The use of cellulose (400 mg) was mandatory to volatilize the halogens from soils with high inorganic matter. It was possible to use diluted absorbing solutions (up to 100 mmol L-1 NH4OH) for halogens retention, providing limits of quantification in the range of 0.06 (I) to 60 (Cl) µg g-1. Accuracy was evaluated using certified reference materials (CRMs), spiked samples, and pyrohydrolysis method. Recoveries for halogens after spiked samples were in the range of 94 to 103% and the results after digestion of CRMs by MIC were in agreement better than 95% to certified values. Blanks were low, relative standard deviation was below 8% for all soils and no statistical difference was observed for results by pyrohydrolysis and MIC methods showing the feasibility of the proposed method for further halogens determination in soil samples.

Long-Term Efficacy and Safety of Cyclosporine in a Cohort of Steroid-Refractory Acute Severe Ulcerative Colitis Patients from the ENEIDA Registry (1989-2013): A Nationwide Multicenter Study.

OBJECTIVES: To determine the efficacy and safety of cyclosporine (CyA) in a large national registry-based population of patients with steroid-refractory (SR) acute severe ulcerative colitis (ASUC) and to establish predictors of efficacy and adverse events. METHODS: Multicenter study of SR-ASUC treated with CyA, based on data from the ENEIDA registry. SR-ASUC patients treated with infliximab (IFX) or sequential rescue therapy (CyA-IFX or IFX-CyA) were used as comparators. RESULTS: Of 740 SR-ASUC patients, 377 received CyA, 131 IFX and 63 sequential rescue therapy. The cumulative colectomy rate was higher in the CyA (24.1%) and sequential therapy (32.7%) than in the IFX group (14.5%; P=0.01) at 3 months and 5 years. There were no differences in early and late colectomy between CyA and IFX in patients treated after 2005. 62% of patients receiving CyA remained colectomy-free in the long term (median 71 months). There were no differences in mortality between CyA (2.4%), IFX (1.5%) and sequential therapy (0%; P=0.771). The proportion of patients with serious adverse events (SAEs) was lower in CyA (15.4%) than in IFX treated patients (26.5%) or sequential therapy (33.4%; P<0.001). This difference in favor of CyA was maintained when only patients treated after 2005 were analyzed. CONCLUSIONS: Treatment with CyA showed a lower rate of SAE and a similar efficacy to that of IFX thereby supporting the use of either CyA or IFX in SR-ASUC. In addition, the risk-benefit of sequential CyA-IFX for CyA non-responders is acceptable.

Association between bone turnover markers, clinical variables, spinal syndesmophytes and bone mineral density in Mexican patients with ankylosing spondylitis.

OBJECTIVES: To compare bone turnover marker (BTM) levels and bone mineral density (BMD) between patients with ankylosing spondylitis (AS) and healthy controls (HC) and to evaluate, in AS, the association between BTM levels and clinical variables, spinal syndesmophytes, and BMD using multivariate analysis. METHOD: Seventy-eight AS patients were compared with 58 HC matched by gender. Spinal syndesmophytes in AS and other characteristics were assessed. C-terminal telopeptide fragments of type I collagen (CTX), bone-specific alkaline phosphatase (BAP), osteocalcin (OC) serum levels, and BMD of the lumbar spine, femoral neck, and forearm were evaluated. RESULTS: AS males and females had lower BAP levels than their respective HC (p < 0.001 and p = 0.001). AS patients with bridging syndesmophytes had higher OC levels than AS patients either with non-bridging syndesmophytes (p = 0.001) or without spinal syndesmophytes (p < 0.001). OC and CTX levels correlated significantly with the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). In the multivariate linear regression adjusted by age, gender, the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), BMD in the lumbar spine, and C-reactive protein (CRP), we observed an association between BAP levels and anti-tumour necrosis factor (anti-TNF) use (p = 0.05) whereas OC levels were associated with mSASSS (p < 0.001) and anti-TNF use (p = 0.05), and CTX levels were exclusively associated with mSASSS (p = 0.03). In the logistic regression analysis, only OC levels were associated with the presence of syndesmophytes in AS [odds ratio (OR) 2.42, 95% confidence interval (CI) 1.19-5.75]. CONCLUSIONS: We observed an increase in OC levels in AS patients with syndesmophytes. BTM levels were associated with the severity of spinal damage. Future longitudinal studies should evaluate whether these BTMs should be included as tools to determine the prognosis and progression of spinal damage.

Pastoralism in the drylands of Latin America: Argentina, Chile, Mexico and Peru. / Pastoralismo en zonas áridas de Latinoamérica: Argentina, Chile, México y Perú.

This article discusses various aspects of pastoralism in the Latin American countries with the largest dryland areas. The topics covered include: social, economic and institutional issues; grasslands and their carrying capacity; production systems and productivity rates; competition for forage resources between domestic livestock and wildlife; and the health status of livestock and wildlife. Most grasslands exhibit some degree of degradation. The percentage of offspring reaching weaning age is low: 47-66% of calves and 40-80% of lambs. Some pastoralists adopt patterns of transhumance. In the main, pastoralists experience a high poverty rate and have poor access to social services. For many pastoralists, wildlife is a source of food and by-products. Argentina, Chile, Mexico and Peru have animal health control agencies, are members of the World Organisation for Animal Health (OIE) and have signed the United Nations Convention to Combat Desertification. Pastoral systems subsist mainly on income unrelated to pastoral farming. The OIE recognises all four countries as free from infection with peste des petits ruminants virus, and from rinderpest and African horse sickness. It is difficult to predict the future of pastoralism in Latin America because the situation differs from country to country. For instance, pastoralism is more important in Peru than in Argentina, where it is a more marginal activity. In the future, lack of promotion and protection policies could lead to a decline in pastoralism or to an adverse environmental impact on drylands.

Les auteurs abordent les particularités du pastoralisme dans les quatre pays d'Amérique latine dotés des plus vastes étendues de terres arides du souscontinent ; ils examinent notamment les aspects sociaux, économiques et institutionnels du pastoralisme, les pâtures et leur capacité de charge, les systèmes de production et les indices de productivité, la concurrence entre le bétail et les animaux sauvages pour le prélèvement de fourrage et le statut sanitaire respectif des animaux d'élevage et de la faune sauvage. Les prairies dédiées au pastoralisme présentent dans leur majorité un certain degré de dégradation. Le taux de survie au sevrage fluctue entre 47 % et 66 % pour les veaux et entre 40 % et 80 % pour les agneaux. Certains pasteurs adoptent des schémas de transhumance. Les populations pastorales se caractérisent par un niveau élevé de pauvreté et un accès très limité aux services sociaux. Pour de nombreux pasteurs, la faune sauvage constitue une ressource alimentaire directe mais elle fournit aussi des produits dérivés. En Argentine, au Chili, au Mexique et au Pérou, des services gouvernementaux sont chargés du contrôle de la santé animale. Ces pays sont Membres de l'Organisation mondiale de la santé animale (OIE) et signataires de la Convention des Nations Unies sur la lutte contre la désertification. Les systèmes pastoraux subsistent essentiellement grâce à des revenus autres que ceux issus de la production. Ces territoires ont été reconnus par l'OIE comme étant indemnes d'infection par les virus de la peste des petits ruminants, de la peste bovine et de la peste équine. Il est difficile de prédire l'avenir du pastoralisme en Amérique latine, en raison de la diversité des situations rencontrées d'un pays à l'autre. Par exemple, l'activité pastorale est plus importante au Pérou qu'en Argentine où elle a un caractère marginal. L'absence de politiques de promotion et de protection spécifiques pourrait se traduire à l'avenir par un déclin du pastoralisme ou par un impact écologique négatif pour ces zones arides.

Se abordan matices del pastoralismo relativos a los países con mayor extensión de zonas áridas de Latinoamérica, concretamente, los aspectos sociales, económicos e institucionales, los pastizales y su receptividad, los sistemas de producción e índices de productividad, la competencia entre ganado doméstico y fauna silvestre por el recurso forrajero, y el estatus sanitario del ganado y de los animales silvestres. La mayor parte de los pastizales presenta algún grado de deterioro. El porcentaje de crías que llega al destete fluctúa entre el 47% y el 66% en bovinos y entre el 40% y el 80% en ovinos. Algunos pastoralistas adoptan patrones de trashumancia. Los pastores se caracterizan básicamente por un índice alto de pobreza y un escaso acceso a los servicios sociales. La fauna es un recurso alimentario y una fuente de subproductos para numerosos pastores. Argentina, Chile, México y Perú cuentan con organismos destinados al control de la sanidad animal, son miembros de la OIE y han suscrito la Convención de las Naciones Unidas de Lucha contra la Desertificación. Los sistemas pastoriles subsisten principalmente a partir de ingresos ajenos a su producción. La OIE reconoce a estos territorios como libres de infección por peste de los pequeños rumiantes, por peste bovina y por peste equina. Es difícil predecir el futuro del pastoralismo en Latinoamérica debido a las diferentes situaciones de cada país. Así, por ejemplo, en Perú, esta práctica tiene mayor importancia que en Argentina, donde es más marginal. La carencia de políticas de promoción y protección podría conducir en el futuro a una disminución de la actividad o a un impacto ecológico negativo en las zonas áridas.

Soil mercury levels in the area surrounding the Cerro Prieto geothermal complex, MEXICO.

Even though geothermal energy is a renewable energy source that is seen as cost-effective and environmentally friendly, emissions from geothermal plants can impact air, soil, and water in the vicinity of geothermal power plants. The Cerro Prieto geothermal complex is located 30 km southeast of the city of Mexicali in the Mexican state of Baja California. Its installed electricity generation capacity is 720 MW, being the largest geothermal complex in Mexico. The objective of this study was to evaluate whether the emissions generated by the geothermal complex have increased the soil mercury concentration in the surrounding areas. Fifty-four surface soil samples were collected from the perimeter up to an approximate distance of 7660 m from the complex. Additionally, four soil depth profiles were performed in the vicinity of the complex. Mercury concentration in 69 % of the samples was higher than the mercury concentration found at the baseline sites. The mercury concentration ranged from 0.01 to 0.26 mg/kg. Our results show that the activities of the geothermal complex have led to an accumulation of mercury in the soil of the surrounding area. More studies are needed to determine the risk to human health and the ecosystems in the study area.