Incidence and risk factors of distal adjacent disc degeneration in adolescent idiopathic scoliosis patients undergoing fusion surgery: a systematic review and meta-analysis

PURPOSE

The objective of this meta-analysis was to determine the incidence of disc degeneration in patients with surgically treated adolescent idiopathic scoliosis (AIS) and identify the associated risk factors.

METHODS

PubMed, EMBASE, Scopus, and Cochrane Collaboration Library databases were searched. The outcomes of interest were the incidence of disc degeneration, SRS-22, and radiological risk factors. The lower instrumented vertebra (LIV) was also evaluated. Fixed effects were used if there was no evidence of heterogeneity. Statistical analysis was performed using Review Manager.

RESULTS

A meta-analysis was conducted including nine studies with a total of 565 patients. The analysis revealed that the global incidence of intervertebral disc degeneration in patients with surgically treated AIS patients was 24.78% (95% CI 16.59-32.98%) 10 years after surgery, which significantly increased to 32.32% (95% CI 21.16-43.47% at an average of 13.8 years after surgery. Among patients with significant degenerative disc changes, the SRS-22 functional, self-image, and satisfaction domains showed significantly worse results (MD - 0.25, 95% CI - 0.44 to - 0.05; MD - 0.50, 95% CI - 0.75 to - 0.25; and MD - 0.34, 95% CI - 0.66 to - 0.03, respectively). Furthermore, instrumentation at or above the L3 level was associated with a lower incidence of intervertebral disc degeneration compared to instrumentation below the L3 level (OR 0.25, 95% CI 0.10-0.64). It was also found that the preoperative and final follow-up lumbar curve magnitudes (MD 8.11, 95% CI 3.82-12.41) as well as preoperative and final follow-up lumbar lordosis (MD 0.42, 95% CI - 3.81 to 4.65) were associated with adjacent disc degeneration.

CONCLUSIONS

This meta-analysis demonstrated that the incidence of intervertebral disc degeneration significantly increased with long-term follow-up using fusion techniques, reaching up to 32% when patients were 28 years of age. Incomplete correction of deformity and fusion of levels below L3, were identified as negative prognostic factors. Furthermore, patients with disc degeneration showed worse functional outcomes.

Elevated blood metal ion levels in patients undergoing instrumented spinal surgery: a systematic review and meta-analysis

BACKGROUND CONTEXT

Elevated blood metal levels have been reported in patients after spinal surgery using metallic implants. Although some studies have suggested an association between heightened blood metal concentrations and potential adverse effects, estimates of the incidence of abnormal metal levels after spinal surgery have been inconsistent.

PURPOSE

The aims of this systematic review and meta-analysis were to assess: (1) mean differences in blood metal ion levels between patients undergoing spinal fusion surgery and healthy controls, (2) odds of elevated blood metal ion levels after surgery compared to pre-surgery levels, and (3) pooled incidence of elevated blood metal ions overall and by metal type.

STUDY DESIGN

Systematic review and meta-analysis.

PATIENTS SAMPLE

The patient sample included 613 patients from 11 studies who underwent spinal surgery instrumentation.

OUTCOME MEASURES

Blood metal ion concentrations and the incidence of patients with elevated metal levels compared with in those the control group.

METHODS

A comprehensive search was conducted in PubMed, EMBASE, Scopus, and Cochrane Library to identify studies reporting blood metal ion levels after spinal fusion surgery. Mean differences (MD), odds ratios (OR), and incidence rates were pooled using random effects models. Heterogeneity was assessed using I2 statistics, and fixed-effects models were used if no heterogeneity was detected. Detailed statistical analysis was performed using the Review Manager version 5.4 software.

RESULTS

The analysis included 11 studies, with a total of 613 patients. Mean blood metal ion levels were significantly higher after spinal fusion surgery (MD 0.56, 95% CI 0.17-0.96; I2=86%). Specifically, titanium levels were significantly elevated (MD 0.81, 95% CI 0.32-1.30; I2=47%). The odds of elevated blood metal ions were higher after surgery (OR 8.17, 95% CI 3.38-19.72; I2=41%), primarily driven by chromium (OR 23.50, 95% CI 5.56-99.31; I2=30%). The incidence of elevated chromium levels was found to be 66.98% (95% CI 42.31-91.65).

CONCLUSION

In conclusion, blood metal ion levels, particularly titanium and chromium, were significantly increased after spinal fusion surgery compared to pre-surgery levels and healthy controls. Approximately 70% of the patients exhibited elevated blood levels of chromium and titanium.

Reply to Lemans et al. Comment on "Burgos et al. Fusionless All-Pedicle Screws for Posterior Deformity Correction in AIS Immature Patients Permit the Restoration of Normal Vertebral Morphology and Removal of the Instrumentation Once Bone Maturity Is Reached. J. Clin. Med. 2023, 12, 2408"

We thank Dr. Lemans and coworkers for their interest and knowledgeable comments [...].

Fusionless All-Pedicle Screws for Posterior Deformity Correction in AIS Immature Patients Permit the Restoration of Normal Vertebral Morphology and Removal of the Instrumentation Once Bone Maturity Is Reached

The aim of this study was to report the restoration of normal vertebral morphology and the absence of curve progression after the removal of instrumentation in AIS patients that underwent posterior correction of the deformity by a common all-screws construct without fusion. A series of 36 AIS immature patients (Risser 3 or less) were included in the study. Instrumentation was removed once the maturity stage was complete (Risser 5). The curve correction was assessed pre- and postoperatively, before instrumentation removal, directly post-removal, and more than two years after instrumentation was removed. Epiphyseal vertebral growth modulation was assessed by the coronal wedging ratio (WR) at the apical level of the main curve (MC). The mean preoperative coronal Cobb was corrected from 53.7° ± 7.5 to 5.5° ± 7.5° (89.7%) at the immediate postop. After implant removal (31.0 ± 5.8 months), the MC was 13.1°. T5-T12 kyphosis showed significant improvement from 19.0° before curve correction to 27.1° after implant removal (p < 0.05). Before surgery, the WR was 0.71 ± 0.06, and after removal, 0.98 ± 0.08 (p < 0.001). At the end of the follow-up, the mean sagittal range of motion (ROM) of the T12-S1 segment was 51.2 ± 21.0°. The SRS-22 scores improved from 3.31 ± 0.25 preoperatively to 3.68 ± 0.25 at the final assessment (p < 0.001). In conclusion, a fusionless posterior approach using common all-pedicle screws correctly constructed satisfactory scoliotic main curves and permitted the removal of instrumentation once bone maturity was reached. The final correction was highly satisfactory, and an acceptable ROM of the previously lower instrumented segments was observed.

Bibliometric analysis in paediatric dental journals listed in journal citation reports. Current trends

AIM

The aim of this study was to analyse articles published in paediatric dental journals included in Journal Citation Reports (JCR), to determine current trends in paediatric publishing.

METHODS

Articles included in paediatric dentistry journals in 2020 JCR were selected, published during the period 2008-2020. After applying inclusion criteria, author-based parameters (article title, first author's name, institution, sex and number of authors, number of affiliations, first/last author's origin and geographic origin), and article-based parameters (article type, main topic, research design) were registered for each article.

CONCLUSION

International Journal of Paediatric Dentistry, Journal of Clinical Pediatric Dentistry, European Journal of Paediatric Dentistry and Pediatric Dentistry were the four main journals in terms of production volume, USA being the most productive country. The most recurrent topic was dental surgery, and the most common design was observational studies. Study design, geographic origin of the articles, article type and main subject of the article might predict citation.

Deep transfer learning for the recognition of types of face masks as a core measure to prevent the transmission of COVID-19

The use of face masks in public places has emerged as one of the most effective non-pharmaceutical measures to lower the spread of COVID-19 infection. This has led to the development of several detection systems for identifying people who do not wear a face mask. However, not all face masks or coverings are equally effective in preventing virus transmission or illness caused by viruses and therefore, it appears important for those systems to incorporate the ability to distinguish between the different types of face masks. This paper implements four pre-trained deep transfer learning models (NasNetMobile, MobileNetv2, ResNet101v2, and ResNet152v2) to classify images based on the type of face mask (KN95, N95, surgical and cloth) worn by people. Experimental results indicate that the deep residual networks (ResNet101v2 and ResNet152v2) provide the best performance with the highest accuracy and the lowest loss.

PERSONAL DOSIMETRY USING MONTE-CARLO SIMULATIONS FOR OCCUPATIONAL DOSE MONITORING IN INTERVENTIONAL RADIOLOGY: THE RESULTS OF A PROOF OF CONCEPT IN A CLINICAL SETTING

Exposure levels to staff in interventional radiology (IR) may be significant and appropriate assessment of radiation doses is needed. Issues regarding measurements using physical dosemeters in the clinical environment still exist. The objective of this work was to explore the prerequisites for assessing staff radiation dose, based on simulations only. Personal dose equivalent, Hp(10), was assessed using simulations based on Monte Carlo methods. The position of the operator was defined using a 3D motion tracking system. X-ray system exposure parameters were extracted from the x-ray equipment. The methodology was investigated and the simulations compared to measurements during IR procedures. The results indicate that the differences between simulated and measured staff radiation doses, in terms of the personal dose equivalent quantity Hp(10), are in the order of 30-70 %. The results are promising but some issues remain to be solved, e.g. an automated tracking of movable parts such as the ceiling-mounted protection shield.

Biomechanical analysis of expert anesthesiologists and novice residents performing a simulated central venous access procedure

BACKGROUND

Central venous access (CVA) is a frequent procedure taught in medical residencies. However, since CVA is a high-risk procedure requiring a detailed teaching and learning process to ensure trainee proficiency, it is necessary to determine objective differences between the expert's and the novice's performance to guide novice practitioners during their training process. This study compares experts' and novices' biomechanical variables during a simulated CVA performance.

METHODS

Seven experts and seven novices were part of this study. The participants' motion data during a CVA simulation procedure was collected using the Vicon Motion System. The procedure was divided into four stages for analysis, and each hand's speed, acceleration, and jerk were obtained. Also, the procedural time was analyzed. Descriptive analysis and multilevel linear models with random intercept and interaction were used to analyze group, hand, and stage differences.

RESULTS

There were statistically significant differences between experts and novices regarding time, speed, acceleration, and jerk during a simulated CVA performance. These differences vary significantly by the procedure stage for right-hand acceleration and left-hand jerk.

CONCLUSIONS

Experts take less time to perform the CVA procedure, which is reflected in higher speed, acceleration, and jerk values. This difference varies according to the procedure's stage, depending on the hand and variable studied, demonstrating that these variables could play an essential role in differentiating between experts and novices, and could be used when designing training strategies.

Pre-existing comorbidity, the highest risk factor for poor prognosis of COVID-19 among the Mexican population

The coronavirus disease 2019 (COVID-19) pandemic represents a challenge for public health and a high risk for patients with pre-existing comorbidity. As of July 20, 2020, the Case Fatality Rate (CFR) was 11.30% and the Mortality Rate (MR) was 31.28 deaths per 100,000 population. In Mexico, the prevalence of obesity, diabetes mellitus, and hypertension among the adult Mexican population is 30%, 9.2%, and 40%, respectively. The objective of this research was to identify the risk factors associated with eight comorbidities and their dependency on age for death caused by COVID-19. Method: This study used the dataset published on July 20, 2020, by the General Directorate of Epidemiology of the Ministry of Health of Mexico. From this dataset, we analysed 130,896 positive COVID-19 cases, where 35,483 (27.107%) patients had one comorbidity, and 95,413 (72.892%) patients had not medical comorbidity. Statistical analyses include the Case Fatality Rate (CFR), the estimation of the Odds Ratio (OR), and its 95% Confidence Interval (CI). Results: The highest CFR was 14.382% for COPD, 10.266% for CKD, 10.126% for diabetes, and 8.954% for hypertension. The obesity CFR was 3.535%. Moreover, we detected a higher risk for patients with COPD, diabetes, and CKD, resulting in OR of 4.443 (95% CI: 3.404-5.799), 3.283 (95% CI: 3.018-3.570), and 3.016 (95% CI: 2.248-4.047), respectively.   Conclusion: This study corroborates that the highest risk for severe disease and death caused by COVID-19 among the Mexican population are pre-existing comorbidities. Findings show that COPD, CKD, diabetes, hypertension, and cardiovascular disease increase the risk of death for patients older than 54 years. The most vulnerable age group is older than 65 years.

Role of boost radiotherapy for local control of pure ductal carcinoma in situ after breast-conserving surgery: a multicenter, retrospective study of 622 patients

PURPOSE

To evaluate the effect of boost radiotherapy on ipsilateral breast tumor recurrence (IBTR) for ductal carcinoma in situ (DCIS) after breast-conserving surgery and whole breast radiotherapy (WBRT) with or without boost.

METHODS AND MATERIALS

Retrospective, multicentre study of 622 patients (624 tumors) diagnosed with pure DCIS from 1993-2011.

RESULTS

Most tumors (377/624; 60.4%) received a boost. At a median follow-up of 8.8 years, IBTR occurred in 64 cases (10.3%). A higher percentage of patients with risk factors for IBTR received a boost (p < 0.05). Boost was not associated with lower rates of IBTR than WBRT alone (HR 0.75, 95% CI 0.42-1.35). On the univariate analyses, IBTR was significantly associated with tumor size (11-20 mm, HR 2.32, 95% CI 1.27-4.24; and > 20 mm, HR 2.10, 95% CI 1.14-3.88), re-excision (HR 1.76, 95% CI 1.04-2.96), and tamoxifen (HR 2.03, 95% CI 1.12-3.70). Boost dose > 16 Gy had a protective effect (HR 0.39, 95% CI 0.187-0.824). Multivariate analyses confirmed the independent associations between IBTR and 11-20 mm (p = 0.02) and > 20 mm (p = 0.009) tumours, and re-excision (p = 0.006). On the margin-stratified multivariate analysis, tamoxifen was a poor prognostic factor in the close/positive margin subgroup (HR 4.28 95% CI 1.23-14.88), while the highest boost dose ( > 16 Gy) had a significant positive effect (HR 0.34, 95% CI 0.13-0.86) in the negative margin subgroup.

CONCLUSIONS

Radiotherapy boost did not improve the risk of IBTR. Boost radiotherapy was more common in patients with high-risk disease. Tumor size and re-excision were significant independent prognostic factors.

Impact of flash flood events on the distribution of organic pollutants in surface sediments from a Mediterranean coastal lagoon (Mar Menor, SE Spain)

The influence of flash flood events on the input and distribution of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorinated pesticides (OCPs) in surface sediments from the Mar Menor lagoon were characterized in this study. These contaminants were analyzed in surface water samples collected during two flash flood events in the main surface watercourse which flow into the Mar Menor lagoon. Surface sediments were sampled semiannually before and after flash flood events. The total input of PAHs, OCPs, and PCBs (sorbed + dissolved) during two flash flood events was estimated at 0.98, 1.32, and 0.34 kg, respectively, the main input corresponding to p,p'-DDE (1.00 kg). The distribution of organic contaminants in surface sediments was not homogeneous as a consequence of the presence of many simultaneous sources and different meteorological, hydrodynamic, and physicochemical conditions. As a consequence of flash flood events, p,p'-DDE concentrations in surface sediments increased significantly in the central and south zones of the lagoon. However, in the case of PCBs, a dilution effect was observed in the south zone after such events, reducing the environmental risk. These changes in the pollutant distribution persisted at least 1 year later (autumn 2010), showing that the impact of flood events in the distribution of persistent organic contaminants in Mediterranean coastal lagoons is of relevance according to the ecological risk assessment carried out. The impact of these events should be also considered in other coastal systems, especially in semiarid and semiconfined areas.

Abstract P5-17-08: Study of boost radiotherapy's influence on local control in 646 pure ductal carcinoma in situ breast cancer with long-term follow-up

BACKGROUND: Boost radiotherapy (B-RT) improves outcome in patients (pts) with invasive breast cancer. It's use in patients with pure ductal carcinoma in situ (DCIS) is unclear. There are two ongoing randomize trials, results are expected in ten years. Twelve retrospective observational studies have been published since 2006, the recent meta-analysis, support boost in the presence of positive margins.

PATIENTS and METHODS: We analyse a retrospective women's cohort of 646 pure DCIS patients (pts) treated mainly in two Hospitals (n=518) from 1993 to 2014. The other ten Hospitals included 128 pts all 2005 long. Proportions were compared by boost status, using the chi-square tests. The impact of boost radiation on the development of local recurrence (LR) was determined using survival analyses. In the comparison of Kaplan-Meier (K-M) was used log-rank test.

RESULTS: B-RT subgroup is 394 pts (61%), noB-RT 252 (39%). Median follow-up (FU) is 8.8 years. High risk factors: young age, size, margin status and tamoxifen (TMX) show differences among B-RT (p&lt;0.05). 46% were Estrogen Receptor positive (ER+), 30% B-RT and 16% noB-RT. 22% RE+ in B-RT take TMX vs 9.4 % RE+ noB-RT. Total LR 65 (10%). In situ LR 30 pts (4,6%) and Invasive (Inv) 35 (5,4%). By subgroup, LR in B-RT 47 (12%) vs. 18 (7%) in noB-RT. By subtype, In situ LR in B-RT 20 (5.1%) vs. noB-RT 10 (4%). Inv LR in B-RT 27 (6.9%) vs. noB-RT 8 (3.2%). In uni & multivariate analysis, tumour size, Re-Excision, and TMX, are significant LR risk factors (p&lt;0.05). Boost total doses &gt;16 Gy in the B-RT subgroup is a LR significant risk factor related to 10-16 Gy (p∼0.05). TMX and Dose Boost are related (p&lt;0.001). When Dose is introduced in multivariate analysis model, TMX lost signification. Contralateral local recurrence (CLR) in 29 pts (7%). Second tumours 9 pts (NSD between subgroups). Global disease free survival (DFS) is 80.5%, 77% in B-RT vs. 85% in noB-RT. Four pts have a LR combined with CLR; 2 pts have a LR and a second tumor; 1 pt with CLR and second tumour; 1 pt a Inv regional recurrence; 1 pt mixosarcoma in ipsilateral breast and lung metastases. Deaths: 3 pts (0.5%) after an Inv LR; 3 pts (0.5%) after Inv CR; 20 pts other causes; 10 pts lost their FU. Median FU in B-RT subgroup was 9y vs. 8.3y in noB-RT. The maximum FU according LR in B-RT is 20.6y vs. 17.4y in noB-RT. RL is not significant according to Boost (K-M p=0.398). Median LR in situ or inv depending of B-RT vs. noB-RT shows NSD (p=0.663).

CONCLUSIONS: In this large cohort retrospective study with long-term follow-up B-RT was associated with similar LR as noB-RT despite being used more frequently with higher risk disease. Dose boost &gt;16 Gy has a protective effect. Tamoxifen and boost dose are related variables. Further evidence, based on ongoing randomized trials results is essential.

Citation Format: Cambra MJ, Moreno F, Sanz X, Anglada L, Moià M, Reyes V, Arenas M, Pedro A, Ballester R, García V, Sanjosé S, Cusidó M, Jimenez C, Macià M, Solé JM, Farrus B. Study of boost radiotherapy's influence on local control in 646 pure ductal carcinoma in situ breast cancer with long-term follow-up. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-17-08.

Endometria from Obese PCOS Women with Hyperinsulinemia Exhibit Altered Adiponectin Signaling

Hyperandrogenemia, hyperinsulinemia, and obesity affect 60-70% of patients with Polycystic Ovarian Syndrome (PCOS), who exhibit an altered endometrial insulin signaling. The aim of the study was to evaluate whether hyperandrogenism, hyperinsulinism, and obesity present in PCOS patients impair the endometrial adiponectin signaling pathway. The ex vivo study was conducted on 27 samples from lean (n=9), obese (n=9), and obese-PCOS (n=9) patients. The in vitro assays were performed in immortalized human endometrial stromal cells stimulated with testosterone, insulin, or testosterone plus insulin. Serum steroid-hormones, adiponectin, glucose, and insulin; body mass index, free androgen index, ISI-Composite, and HOMA were evaluated in the 3 groups. Ex vivo and in vitro gene expression and protein content of adiponectin, AdipoR1, AdipoR2, and APPL1 were determined. Adiponectin serum levels were decreased in obese-PCOS patients compared to lean (78%) and obese (54%) controls (p<0.05). AdipoR1 protein and gene expression were increased in obese group vs. obese-PCOS and lean groups (2-fold, p<0.05). In turn, AdipoR2 protein and mRNA content was similar between the 3 groups. APPL1 protein levels were reduced in endometria from both obese groups, compared to lean group (6-fold, p<0.05). Testosterone plus insulin stimulation of T-HESC and St-T1b leads to a reduction of adiponectin, AdipoR1, AdipoR2, and APPL1 protein content in both endometrial cell lines (p<0.05), whereas, in the presence of testosterone or insulin alone, protein levels were similar to basal. Therefore, endometrial adiponectin-signaling pathway is impaired in hyperandrogenemic and hyperinsulinemic obese-PCOS patients, corroborated in the in vitro model, which could affect endometrial function and potentially the implantation process.

[Impact of quality improvement process upon the state of nutritional support in a critical care unit]

INTRODUCTION

In a preceding article the state of Nutritional support (NS) in an Intensive Care Unit (ICU) was documented [Martinuzzi A et al. Estado del soporte nutricional en una unidad de Cuidados críticos. RNC 2011; 20: 5-17]. In this follow-up work we set to assess the impact of several organizational, recording and educational interventions upon the current state of NS processes.

MATERIALS AND METHODS

Interventions comprised presentation of the results of the audit conducted at the ICU before the institution's medical as well as paramedical personnel; their publication in a periodical, peer-reviewed journal; drafting and implementation of a protocol regulating NS schemes to be carried out at the ICU; and conduction of continuous education activities on Nutrition (such as "experts talks", interactive courses, and training in the implementation of the NS protocol). The state of NS processes documented after the interventions was compared with the results annotated in the preceding article. Study observation window ran between March the 1st, 2011 and May 31th, 2011, both included.

RESULTS

Study series differed only regarding overall-mortality: Phase 1: 40.0% vs. Phase 2: 20.5%; Difference: 19.5%; Z = 1.927; two-tailed-p = 0.054. Interventions resulted in a higher fulfillment rate of the prescribed NS indication; an increase in the number of patients receiving ≥ 80% of prescribed energy; and a reduction in the number of NS lost days. Mortality was (numerically) lower in patients in which the prescribed NS scheme was fulfilled, NS was early initiated, and whom received ≥ 80% of prescribed energy. Adopted interventions had no effect upon average energy intakes: Phase 1: 574.7 ± 395.3 kcal/24 h⁻¹ vs. Phase 2: 591.1 ± 315.3 kcal/24 h⁻¹; two-tailed-p > 0.05.

CONCLUSIONS

Educational, recording and organizational interventions might result in a better conduction of NS processes, and thus, in a lower mortality. Hemodynamic instability is still the most formidable obstacle for initiating and completing NS.

Resultados a largo plazo de prótesis de cúbito distal como cirugía de rescate en un caso de técnica de Sauvé-Kapandji fallida

La técnica de Sauvé-Kapandji se emplea como tratamiento de rescate en la patología de la articulación radiocubital distal (ARCD). Los resultados postoperatorios son buenos, aunque a largo plazo pueden surgir complicaciones como dolor, muñón cubital inestable y pérdida de fuerza de prensión. Presentamos un caso de cirugía de rescate de esta técnica mediante prótesis de cúbito distal. A los cuatro años de seguimiento, el paciente presenta desaparición completa del dolor y recuperación de la fuerza de prensión, lo que hace pensar que la prótesis cubital puede ser un buen método de rescate cuando fracasa un Sauvé-Kapandji.

Laparoscopic repair of non-complicated lumbar hernia secondary to a latissimus dorsi flap

Lumbar hernia is an unusual complication of the latissimus dorsi flap. Traditionally, it has always been repaired using open-surgery techniques. We present the first description of laparoscopic surgery to treat a non-complicated superior lumbar hernia resulting from the creation of an enlarged latissimus dorsi myocutaneous flap for breast reconstruction following left modified radical mastectomy. The laparoscopic approach substantially reduced the risks associated with open surgery, shortened length of hospital stay and time to recovery and obtained better cosmetic results. Laparoscopic surgery may be considered as a feasible therapeutic option for non-complicated superior lumbar hernias secondary to a latissimus dorsi muscle flap.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Seasonal input of regulated and emerging organic pollutants through surface watercourses to a Mediterranean coastal lagoon

Seasonal input of organic pollutants through El Albujón Watercourse to the Mar Menor lagoon was estimated from Spring 2009 to Winter 2010, including regular periods and two flash flood events. 82 semivolatile organic pollutants (persistent organic pollutants, different groups of pesticides and others) were determined by stir bar sorptive extraction and thermal desorption followed by capillary gas chromatography coupled to mass spectrometry from surface waters with quantification limits of a few ngL(-1). Pesticide concentrations varied significantly along the watercourse due to the presence of different sources (groundwaters, wastewater effluent, tributary contributions, brackish waters, etc.) and physicochemical/biological processes that take place simultaneously. The most commonly detected analytes were propyzamide, triazine compounds and chlorpyrifos. A clear seasonal pattern has been detected, with a predominance of insecticides during Summer and of herbicides during Winter. The input of pesticides through this watercourse is particularly relevant during periods of heavy rain, representing more than 70% of total yearly input for many of them.

Molecular and physiological comparison of spoilage wine yeasts

AIMS

Dekkera bruxellensis and Pichia guilliermondii are contaminating yeasts in wine due to the production of phenolic aromas. Although the degradation pathway of cinnamic acids, precursors of these phenolic compounds has been described in D. bruxellensis, no such pathway has been described in P. guilliermondii.

METHODS AND RESULTS

A molecular and physiological characterization of 14 D. bruxellensis and 15 P. guilliermondii phenol-producing strains was carried out. Both p-coumarate decarboxylase (CD) and vinyl reductase (VR) activities, responsible for the production of volatile phenols, were quantified and the production of 4-vinylphenol and 4-ethylphenol were measured. All D. bruxellensis and some P. guilliermondii strains showed the two enzymatic activities, whilst 11 of the 15 strains of this latter species showed only CD activity and did not produce 4-EP in the assay conditions. Furthermore, PCR products obtained with degenerated primers showed a low homology with the sequence of the gene for a phenyl acrylic acid decarboxylase activity described in Saccharomyces cerevisiae.

CONCLUSIONS

D. bruxellensis and P. guilliermondii may share a similar metabolic pathway for the degradation of cinnamic acids.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first work that analyses the CD and VR activities in P. guilliermondii, and the results suggest that within this species, there are differences in the metabolization of cinnamic acids.

Usefulness of a large field of view sensor for physicochemical, textural, and yield predictions under industrial goat cheese (Murcia al Vino) manufacturing conditions

The applicability of a light backscatter sensor with a large field of view was tested for on-line monitoring of coagulation and syneresis in a goat cheese (Murcia al Vino) manufactured under industrial conditions. Cheesemaking was carried out concurrently in a 12-L pilot vat and a 10,000-L industrial vat following the normal cheesemaking protocol. Cheese moisture, whey fat content, hardness, springiness, and adhesiveness were measured during syneresis. The results obtained show that cutting time is best predicted by considering the coagulation ratio at the inflection point and the percentage increase in the ratio during coagulation, with no need for the first derivative. The large field of view reflectance ratio provided good results for the prediction of moisture content, yield, hardness, springiness, and adhesiveness of the final cheese.

Software architecture for multi-bed FDK-based reconstruction in X-ray CT scanners

Most small-animal X-ray computed tomography (CT) scanners are based on cone-beam geometry with a flat-panel detector orbiting in a circular trajectory. Image reconstruction in these systems is usually performed by approximate methods based on the algorithm proposed by Feldkamp et al. (FDK). Besides the implementation of the reconstruction algorithm itself, in order to design a real system it is necessary to take into account numerous issues so as to obtain the best quality images from the acquired data. This work presents a comprehensive, novel software architecture for small-animal CT scanners based on cone-beam geometry with circular scanning trajectory. The proposed architecture covers all the steps from the system calibration to the volume reconstruction and conversion into Hounsfield units. It includes an efficient implementation of an FDK-based reconstruction algorithm that takes advantage of system symmetries and allows for parallel reconstruction using a multiprocessor computer. Strategies for calibration and artifact correction are discussed to justify the strategies adopted. New procedures for multi-bed misalignment, beam-hardening, and Housfield units calibration are proposed. Experiments with phantoms and real data showed the suitability of the proposed software architecture for an X-ray small animal CT based on cone-beam geometry.

Performance of a continuous flow microbial electrolysis cell (MEC) fed with domestic wastewater

In this study, MEC performance was investigated in terms of chemical oxygen demand (COD) removal, hydrogen production rate and energy consumption during continuous domestic wastewater (dWW) treatment at different organic loading rates (OLR) and applied voltages (Vapp). While the COD removal efficiency was improved at low OLRs, the electrical energy required to remove 1g of COD was significantly increased with decreasing the OLR. Hydrogen production exhibited a Monod-type trend as function of the OLR reaching a maximum production rate of 0.30 L/(Lrd). Optimal Vapp was found to be highly dependent on the strength of the dWW. The results also confirmed the fact that MEC performance can be optimized by setting Vapp at the onset potential of the diffusion control region. Although low columbic efficiencies and the occurrence of hydrogen recycling limited significantly the reactor performance, these results demonstrate that MEC can be successfully used for dWW treatment.