Textbook outcome in distal pancreatectomy: A multicenter study.

BACKGROUND: Textbook outcome is an interesting quality metrics tool. Information on textbook outcomes in distal pancreatectomy is very scarce. In this study we determined textbook outcome in a distal pancreatectomy multicenter database and propose a specific definition of textbook outcome-distal pancreatectomy that includes pancreatic fistula. METHODS: Retrospective multicenter observational study of distal pancreatectomy performed at 8 hepatopancreatobiliary surgery units from January 1, 2008, to December 31, 2018. The inclusion criteria were any scheduled distal pancreatectomy performed for any diagnosis and age > 18 years. Specific textbook outcome-distal pancreatectomy was defined as hospital stay P < 75, no Clavien-Dindo complications (≥ III), no hospital mortality, and no readmission recorded at 90 days, and the absence of pancreatic fistula (B/C). RESULTS: Of the 450 patients included, 262 (58.2%) obtained textbook outcomes. Prolonged stay was the parameter most frequently associated with failure to achieve textbook outcomes. The textbook outcome group presented the following results. Preoperative: lower American Society of Anesthesiologists score < III, a lower percentage of smokers, and less frequent tumor invasion of neighboring organs or vascular invasion; operative: major laparoscopic approach, and less resection of neighboring organs and less operative transfusion; postoperative: lower percentage of delayed gastric emptying and pancreatic fistula B/C, and diagnosis other an adenocarcinoma. In the multivariate study, the American Society of Anesthesiologists score > II, resection of neighboring organs, B/C pancreatic fistula, and delayed gastric emptying were associated with failure to achieve textbook outcomes. CONCLUSION: The textbook outcome rate in our 450 pancreaticoduodenectomies was 58.2%. In the multivariate analysis, the causes of failure to achieve textbook outcomes were American Society of Anesthesiologists score > II, resection of neighboring organs, pancreatic fistula B/C, and delayed gastric emptying. We believe that pancreatic fistula should be added to the specific definition of textbook outcome-distal pancreatectomy because it is the most frequent complication of this procedure.

Prenatal tobacco exposure on brain morphometry partially mediated poor cognitive performance in preadolescent children.

Objectives: To evaluate whether prenatal tobacco exposure (PTE) is related to poorer cognitive performance, abnormal brain morphometry, and whether poor cognitive performance is mediated by PTE-related structural brain differences. Methods: The Adolescent Brain Cognitive Development study dataset was used to compare structural MRI data and neurocognitive (NIH Toolbox®) scores in 9-to-10-year-old children with (n=620) and without PTE (n=10,989). We also evaluated whether PTE effects on brain morphometry mediated PTE effects on neurocognitive scores. Group effects were evaluated using Linear Mixed Models, covaried for socio-demographics and prenatal exposures to alcohol and/or marijuana, and corrected for multiple comparisons using the false-discovery rate (FDR). Results: Compared to unexposed children, those with PTE had poorer performance (all p-values <0.05) on executive function, working memory, episodic memory, reading decoding, crystallized intelligence, fluid intelligence and overall cognition. Exposed children also had thinner parahippocampal gyri, smaller surface areas in the posterior-cingulate and pericalcarine cortices; the lingual and inferior parietal gyri, and smaller thalamic volumes (all p-values <0.001). Furthermore, among children with PTE, girls had smaller surface areas in the superior-frontal (interaction-FDR-p=0.01), precuneus (interaction-FDR-p=0.03) and postcentral gyri (interaction-FDR-p=0.02), while boys had smaller putamen volumes (interaction-FDR-p=0.02). Smaller surface areas across regions of the frontal and parietal lobes, and lower thalamic volumes, partially mediated the associations between PTE and poorer neurocognitive scores (p-values <0.001). Conclusions: Our findings suggest PTE may lead to poorer cognitive performance and abnormal brain morphometry, with sex-specific effects in some brain regions, in pre-adolescent children. The poor cognition in children with PTE may result from the smaller areas and subcortical brain volumes.

Antioxidant 1 copper chaperone gene expression and copper levels in dog osteosarcoma patients.

Twenty-four dogs with OS underwent limb amputation. Serum, OS tumour, and normal bone were harvested at time of surgery. RNA was extracted and gene expression was performed using quantitative polymerase chain reaction (qPCR). Tissue and blood copper concentrations were also determined with spectrophotometry. Compared to bone, tumour samples had significantly higher expressions of antioxidant 1 copper chaperone (ATOX1, p = .0003). OS tumour copper levels were significantly higher than that of serum (p < .010) and bone (p = .038). Similar to our previous observations in mouse and human OS, dog OS demonstrates overexpression of genes that regulate copper metabolism (ATOX1), and subsequent copper levels. Dogs with OS may provide a robust comparative oncology platform for the further study of these factors, as well as potential pharmacologic interventions.

Validation of a Skin Calorimeter to Determine the Heat Capacity and the Thermal Resistance of the Skin.

In vivo determination of the skin's thermal properties is of growing interest. Several types of sensors are being designed and tested. In this field, we have developed a skin calorimeter for the determination of the heat flow, the heat capacity and the thermal resistance of the skin. The calorimeter calibration consists of the determination of the parameters of the model we have chosen to represent the behavior of the device. This model considers the heat capacity and the thermal resistance of the skin, which depend on the case (body zone, subject, physical state, etc.) and also have a strong time dependence. Therefore, this work includes a validation study with reference materials. Finally, it is concluded that the heat capacity determined is a function of the thermal penetration depth of the measurement characteristics. In the case of high thermal conductivity materials in which the thermal penetration is nearly total, the heat capacity obtained coincides with that of the reference material sample.

Metastasis of Renal Cell Carcinoma to Pancreatic Bile Duct.

Secondary pancreatic neoplasms account for less than 5% of all pancreatic malignancies, with renal cell carcinoma (RCC) being one of the most common primary tumors. Here, we present the case of a patient with obstructive jaundice secondary to an isolated metastatic RCC, to the intrapancreatic portion of the common bile duct, ampulla of Vater, and pancreatic parenchyma. Patient had a history of a left radical nephrectomy due to a primary RCC 10 years prior to presentation, and eventually underwent a pylorus-sparing pancreaticoduodenectomy (PD) with minor morbidity. While metastases of RCC to the pancreatic body and tail have been reported, isolated metastasis to the pancreatic bile duct comprises an even rarer subgroup.

Longitudinal alterations in brain morphometry mediated the effects of bullying victimization on cognitive development in preadolescents.

Bullying victimization is associated with a doubled risk of attempting suicide in adulthood. Two longitudinal brain morphometry studies identified the fusiform gyrus and putamen as vulnerable to bullying. No study identified how neural alterations may mediate the effect of bullying on cognition. We assessed participants with caregiver-reported bullying (N = 323) and matched non-bullied controls (N = 322) from the Adolescent Brain Cognitive Development Study dataset to identify changes in brain morphometry associated with ongoing bullying victimization over two years and determine whether such alterations mediated the effect of bullying on cognition. Bullied children (38.7% girls, 47.7% racial minorities, 9.88 ± 0.62 years at baseline) had poorer cognitive performance (P < 0.05), larger right hippocampus (P = 0.036), left entorhinal cortex, left superior parietal cortex, and right fusiform gyrus volumes (all P < 0.05), as well as larger surface areas in multiple other frontal, parietal, and occipital cortices. Thinner cortices were also found in the left hemisphere, particularly in the left temporal lobe, and right frontal region (all P < 0.05). Importantly, larger surface area in the fusiform cortices partially suppressed (12-16%), and thinner precentral cortices partially mitigated, (7%) the effect of bullying on cognition (P < 0.05). These findings highlight the negative impact of prolonged bullying victimization on brain morphometry and cognition.

Veterinary Spinal Manipulative Therapy or Animal Chiropractic in Veterinary Rehabilitation.

Veterinary rehabilitation is a multimodal diagnostic and treatment approach that is recommended and provided to patients daily. One therapeutic modality that may be beneficial (diagnostically and therapeutically) is veterinary spinal manipulative therapy or animal chiropractic (AC). AC is a receptor-based health-care modality being provided more frequently in veterinary practices. All clinicians should strive to understand the mode of action, indications, contraindications, how it affects the patient from the neuro-anatomical and biomechanical point of view, and most importantly, when not to provide the requested modality, as further diagnostics may be indicated.

Assessing the impact of privacy-preserving record linkage on record overlap and patient demographic and clinical characteristics in PCORnet®, the National Patient-Centered Clinical Research Network.

OBJECTIVE: This article describes the implementation of a privacy-preserving record linkage (PPRL) solution across PCORnet®, the National Patient-Centered Clinical Research Network. MATERIAL AND METHODS: Using a PPRL solution from Datavant, we quantified the degree of patient overlap across the network and report a de-duplicated analysis of the demographic and clinical characteristics of the PCORnet population. RESULTS: There were ∼170M patient records across the responding Network Partners, with ∼138M (81%) of those corresponding to a unique patient. 82.1% of patients were found in a single partner and 14.7% were in 2. The percentage overlap between Partners ranged between 0% and 80% with a median of 0%. Linking patients' electronic health records with claims increased disease prevalence in every clinical characteristic, ranging between 63% and 173%. DISCUSSION: The overlap between Partners was variable and depended on timeframe. However, patient data linkage changed the prevalence profile of the PCORnet patient population. CONCLUSIONS: This project was one of the largest linkage efforts of its kind and demonstrates the potential value of record linkage. Linkage between Partners may be most useful in cases where there is geographic proximity between Partners, an expectation that potential linkage Partners will be able to fill gaps in data, or a longer study timeframe.

Perioperative hyperoxia and myocardial injury after surgery: a randomized controlled trial.

BACKGROUND: The World Health Organization recommends hyperoxia (80% fraction of inspired oxygen, FiO2) during and for 2-6 hours following surgery to reduce surgical site infection (SSI). However, some studies suggest increased cardiovascular complications with such a high perioperative FiO2. The goal of our study was to compare the appearance of cardiovascular complications in elective adult colorectal surgery comparing the use of FiO2>0.8 versus conventional therapy (FiO2<0.4). METHODS: We performed a randomized controlled trial in intubated patients undergoing elective major colorectal surgery. Patients were randomly assigned to receive perioperative FiO2>0.8 or FiO2<0.4. The primary outcome, expressed as Odds Ratio (OR) ±95% Confidence Interval (95%CI), was the incidence of MINS (myocardial injury after noncardiac surgery evaluated for the first 4 postoperative days). Secondary outcomes included MACCE (major adverse cardiovascular and cerebral events) up to 30 postoperative days, SSI, other postoperative complications (according to Clavien-Dindo classification) and length of stay. RESULTS: We included in the final analyses 403 patients. Comparing the FiO2>0.8 and FiO2<0.4 groups, there was no difference in the appearance of MINS (6.0% vs. 10.4%; OR 0.55; 95% CI: 0.26-1.14; P=0.945). There were no differences between the groups for important secondary outcomes including MACCE to 30 days, SSI, postoperative complications or length of stay. CONCLUSIONS: Perioperative hyperoxia therapy (FiO2>0.8) with the aim of decreasing SSI did not increase cardiovascular complications after elective colorectal surgery in a general population.

Establishing a framework for privacy-preserving record linkage among electronic health record and administrative claims databases within PCORnet®, the National Patient-Centered Clinical Research Network.

OBJECTIVE: The aim of this study was to determine whether a secure, privacy-preserving record linkage (PPRL) methodology can be implemented in a scalable manner for use in a large national clinical research network. RESULTS: We established the governance and technical capacity to support the use of PPRL across the National Patient-Centered Clinical Research Network (PCORnet®). As a pilot, four sites used the Datavant software to transform patient personally identifiable information (PII) into de-identified tokens. We queried the sites for patients with a clinical encounter in 2018 or 2019 and matched their tokens to determine whether overlap existed. We described patient overlap among the sites and generated a "deduplicated" table of patient demographic characteristics. Overlapping patients were found in 3 of the 6 site-pairs. Following deduplication, the total patient count was 3,108,515 (0.11% reduction), with the largest reduction in count for patients with an "Other/Missing" value for Sex; from 198 to 163 (17.6% reduction). The PPRL solution successfully links patients across data sources using distributed queries without directly accessing patient PII. The overlap queries and analysis performed in this pilot is being replicated across the full network to provide additional insight into patient linkages among a distributed research network.

Peer victimization (bullying) on mental health, behavioral problems, cognition, and academic performance in preadolescent children in the ABCD Study.

Objective: Peer victimization is a substantial early life stressor linked to psychiatric symptoms and poor academic performance. However, the sex-specific cognitive or behavioral outcomes of bullying have not been well-described in preadolescent children. Methods: Using the baseline dataset of the Adolescent Brain Cognitive Development (ABCD) Study 2.0.1 data repository (N = 11,875), we evaluated associations between parent-reported bullying victimization, suicidality (suicidal ideation, intent, and/or behavior), and non-suicidal self-injury (NSSI), as well as internalizing and externalizing behavioral problems, cognition, and academic performance. Results: Of the 11,015 9-10-year-old children included in the analyses (5,263 girls), 15.3% experienced bullying victimization, as reported by the primary caregiver. Of these, boys were more likely to be bullied than girls (odds ratio [OR], 1.2 [95% CI, 1.1-1.3]; p = 0.004). Children who were bullied were more likely to display NSSI or passive suicidality (OR, 2.4 [95% CI, 2.0-2.9]; p < 0.001) and active suicidality (OR, 3.4 [95% CI, 2.7-4.2]; p < 0.001). Bullied children also had lower cognitive scores, greater behavioral problems, and poorer grades (p < 0.001). Across all participants, boys had poorer grades and greater behavioral problems than girls; however, bullied boys had greater behavioral problems than girls in several areas (p < 0.001). Compared to their non-bullied peers, bullied children with greater non-suicidal self-injury or suicidality also had greater behavioral problems and poorer grades (p < 0.001). Conclusion: These findings highlight the sex-specific effects of bullying, and the negative associations of bullying victimization with cognitive performance, behavioral problems, and academic performance. Future longitudinal studies will identify the natural history and neural correlates of these deficits during adolescence.

Multi-Agent Team Learning in Virtualized Open Radio Access Networks (O-RAN).

Starting from the concept of the Cloud Radio Access Network (C-RAN), continuing with the virtual Radio Access Network (vRAN) and most recently with the Open RAN (O-RAN) initiative, Radio Access Network (RAN) architectures have significantly evolved in the past decade. In the last few years, the wireless industry has witnessed a strong trend towards disaggregated, virtualized and open RANs, with numerous tests and deployments worldwide. One unique aspect that motivates this paper is the availability of new opportunities that arise from using machine learning, more specifically multi-agent team learning (MATL), to optimize the RAN in a closed-loop where the complexity of disaggregation and virtualization makes well-known Self-Organized Networking (SON) solutions inadequate. In our view, Multi-Agent Systems (MASs) with MATL can play an essential role in the orchestration of O-RAN controllers, i.e., near-real-time and non-real-time RAN Intelligent Controllers (RIC). In this article, we first provide an overview of the landscape in RAN disaggregation, virtualization and O-RAN, then we present the state-of-the-art research in multi-agent systems and team learning as well as their application to O-RAN. We present a case study for team learning where agents are two distinct xApps: power allocation and radio resource allocation. We demonstrate how team learning can enhance network performance when team learning is used instead of individual learning agents. Finally, we identify challenges and open issues to provide a roadmap for researchers in the area of MATL based O-RAN optimization.

Pancreatic mucinous cystic neoplasms located in the distal pancreas: a multicenter study.

Background: Mucinous cysts of the pancreas (MCN) are infrequent, usually unilocular tumors which occur in postmenopausal women and are located in the pancreatic body/tail. The risk of malignancy is low. The objective is to define preoperative risk factors of malignancy in pancreatic MCN and to assess the feasibility of the laparoscopic approach. Methods: Retrospective multicenter observational study of prospectively recorded data regarding distal pancreatectomies was carried out at seven hepatopancreatobiliary (HPB) Units between 01/01/08 and 31/12/18 (the ERPANDIS Project). Results: Four hundred and forty-four distal pancreatectomies were recorded including 47 MCN (10.6%). Thirty-five were non-invasive tumors (74.5%). In all, 93% of patients were female, and 60% were ASA (American Society of Anaesthesiology) II. The mean preoperative size was 46 mm. Patients with invasive tumors were older (54 vs. 63 years). Invasive tumors were larger (6 vs. 4 cm), although the difference was not significant (P=0.287). Sixty percent was operated via laparoscopic approach, which was used in 74.6% of non-invasive tumors and in 16.7% of the invasive ones. The spleen was not preserved in 93.6% of the patients. R0 resection was obtained in all patients. Two patients with invasive tumors died. Conclusions: In our surgical series of MCN, patients with malignancy were older and presented larger tumors, although the difference was not statistically significant. Laparoscopy is a safe and feasible approach for MCN. Prospective studies are now needed to define risk factors that can guide the decision whether to administer conservative treatment or to operate.

The Influence of Sleep Quality on Patient Safety Learning of Nursing Students.

ABSTRACT: We investigated the influence of nursing students' sleep quality on their patient safety (PS) competence (i.e., knowledge of the dimensions of PS). The investigation surveyed 242 nursing students in a Saudi university. The majority of the surveyed students were characterized as having poor sleep quality. Notably, more male students experienced poor sleep quality than female students. The students reported the highest confidence in "culture of safety" and "managing safety risk"; they exhibited the poorest confidence in "working in teams." Increased length of sleep latency decreased sleep efficiency, and increased daytime sleepiness-related dysfunction was associated with reduced PS competence.

Towards a Measure for Characterizing the Informational Content of Audio Signals and the Relation between Complexity and Auditory Encoding.

The accurate description of a complex process should take into account not only the interacting elements involved but also the scale of the description. Therefore, there can not be a single measure for describing the associated complexity of a process nor a single metric applicable in all scenarios. This article introduces a framework based on multiscale entropy to characterize the complexity associated with the most identifiable characteristic of songs: the melody. We are particularly interested in measuring the complexity of popular songs and identifying levels of complexity that statistically explain the listeners' preferences. We analyze the relationship between complexity and popularity using a database of popular songs and their relative position in a preferences ranking. There is a tendency toward a positive association between complexity and acceptance (success) of a song that is, however, not significant after adjusting for multiple testing.

Modeling and Experimental Validation of Algorithms for Maximum Quantity of Protein to be Immobilized on Solid Supports by Electrostatic Adsorption in the Strategy of Rational Design of Immobilized Derivatives.

Protein immobilization by electrostatic adsorption to a support could represent a good option. On the other hand, lysozyme (EC 3.2.1.17) is a little and basic protein. The objective of this work was to test the functionality of the strategy of Rational Design of Immobilized Derivatives for the immobilization by electrostatic adsorption of egg white lysozyme on SP-Sepharose FastFlow support. The RDID1.0 software was used to predict the superficial lysozyme clusters, the electrostatic configuration probability for each cluster, and the theoretical and estimated maximum quantity of protein to be immobilized. In addition, immobilization was performed and the experimental parameter practical maximum quantity of protein to be immobilized and the enzymatic activity of the immobilized derivative were assessed. The estimated maximum quantity of protein to be immobilized (9.49 protein mg/support g) was close to the experimental practical maximum quantity of protein to be immobilized (14.73 ± 0.09 protein mg/support g). The enzymatic activity assay with the chitosan substrate showed the catalytic functionality of the lysozyme-SP-Sepharose immobilized derivative (35.85 ± 3.07 U/support g), which preserved 78% functional activity. The used algorithm to calculate the estimated maximum quantity of protein to be immobilized works for other proteins, porous solid supports and immobilization methods, and this parameter has a high predictive value, useful for obtaining optimum immobilized derivatives. The applied methodology is valid to predict the most probable protein-support configurations and their catalytic competences, which concur with the experimental results. The produced biocatalyst had a high retention of functional activity. This indicates its functionality in enzymatic bioconversion processes.

Overweight and obesity significantly reduce pregnancy, implantation, and live birth rates in women undergoing In Vitro Fertilization procedures.

OBJECTIVE: The objective of this study was to evaluate the effects of overweight and obesity on fertility outcomes in IVF procedures. METHODS: This was a retrospective and nonrandomized study that included 191 IVF/ICSI cycles using non-donor oocytes performed between July 2016 and December 2018 that were allocated according to Body Mass Index (BMI) in three groups: Normal group: 18.5-24.9 (n=67 women), Overweight group: 25.0-29.9 (n=86 women) and Obesity group: ≥30.0 (n=38 women). We compared fertilization rates, embryo quality at day 3, development and quality of blastocyst, pregnancy rates, implantation rates, and live birth rates. RESULTS: Patients from all groups had similar stimulation days, but those women with overweight and obesity used more hormones compared to women with normal weight (p<0.05). Fertilization rates, zygotes that underwent cleavage and good-quality embryos at Day 3 were similar between the three evaluated groups. The groups of overweight and obesity had embryos at Day 3 with significantly less cells, compared to those from the normal group (p<0.05). The blastocyst development rate was significantly lower in women with overweight and obesity compared to women with normal BMI (p<0.05); but, the percentages of good blastocysts were similar in all studied patients. Pregnancy, implantation and live birth rates were significantly lower in the group of women with overweight and obesity, compared to those women with normal weight (p<0.05). Obese women had significantly more miscarriages compared to those in the other groups (p<0.05). CONCLUSIONS: Our data shows that an increased BMI affects embryo development and significantly reduces the pregnancy, implantation and live birth rates.

Distal pancreatectomy with multivisceral resection: A retrospective multicenter study - Case series.

BACKGROUND: Multivisceral resection (MVR) is sometimes necessary to achieve disease-free margins in cancer surgery. In certain patients with pancreatic tumors that invade neighboring organs these must be removed to perform an appropriate oncological surgery. In addition, there is an increasing need to perform resections of other organs like liver not directly invaded by the tumor but which require synchronous removal. The results of MVR in pancreatic surgery are controversial. MATERIAL AND METHODS: A distal pancreatectomy retrospective multicenter observational study using prospectively compiled data carried out at seven HPB Units. The period study was January 2008 to December 2018. We excluded DP with celiac trunk resection. RESULTS: 435 DP were performed. In 62 (14.25%) an extra organ was resected (82 organs). Comparison of the preoperative data of MVR and non-MVR patients showed that patients with MVR had lower BMI, higher ASA and larger tumor size. In the MVR group, the approach was mostly laparotomic and spleen preservation was performed only in 8% of the cases, Blood loss and the percentage of intraoperative transfusion were higher in MVR group. Major morbidity rates (Clavien > IIIa) and mortality (0.8vs.4.8%) were higher in the MVR group. Pancreatic fistula rates were practically the same in both groups. Mean hospital stay was twice as long in the MVR group and the readmission rate was higher in the MVR group. Histology study confirmed a much higher rate of malignant tumors in MVR group. CONCLUSIONS: In order to obtain free margins or treat pathologies in several organs we think that DP + MVR is a feasible technique in selected patients; the results obtained are not as good as those of DP without MVR but are acceptable nonetheless. CLINICALTRIALS. GOV IDENTIFIER: NCT04317352.

Reporte de presuntas hipnosporas de Perkinsus sp, en Megapitaria squalida del Golfo de California con la técnica de tinción con tioglicolato / Report of presumptive Perkinsus sp hypnospores in Megapitaria squalida of the Gulf of California with the thioglycollate staining technique

RESUMEN Objetivo. Detectar la presencia de presuntas hipnosporas del protozoario Perkinsus sp. en una población silvestre de la almeja chocolata mexicana (Megapitaria squalida) del sureste del Golfo de California, usando el medio fluido de tioglicolato de Ray (RFTM). Materiales y métodos. Cada mes durante un ciclo anual, se capturaron 30 especímenes con una longitud entre 56.17 y 69.04 mm. La prevalencia e intensidad de la infección y los parámetros del agua se registraron mensualmente desde septiembre 2012 a septiembre 2013. Resultados. Se detectó la presencia de presuntas hipnosporas de Perkinsus sp. en muestras de tejido de la almeja chocolata mexicana usando la prueba RFTM, por la presencia de corpúsculos redondos y oscuros que representan hipnosporas del parásito. Los muestreos mensuales revelaron un rango de prevalencia e intensidad de la infección de 0-43.33% y 1-4 (infección negativa = 0 hipnosporas/preparación, a moderada = 34 hipnosporas/ preparación), respectivamente. Conclusiones. Perkinsus sp. es reportado por primera vez en una población silvestre de M. squalida en la parte más al sureste del Golfo de California. Los resultados indican que el parásito está disperso intraespecíficamente y, potencialmente, parasitaría un nuevo huésped en la región.

ABSTRACT Objective. To detect the presence of presumptive hypnospores of the protozoan Perkinsus sp. in a wild population of the Mexican chocolata clam Megapitaria squalida in the southeastern Gulf of California, using Ray's fluid thioglycollate medium (RFTM). Material and methods. Thirty specimens with size between 56.17 and 69.04 mm were captured each month, during an annual cycle. Infection prevalence and intensity and water parameters were recorded monthly from September 2012 to September 2013. Results. Perkinsus sp. was detected in tissue samples from the Mexican chocolate clam using the RFTM test by the presence of dark round corpuscles that represent parasite's hypnospores. Monthly samplings revealed a prevalence of 0-43.33% and an infection intensity ranging from 1 to 4 (no infection = 0 hypnospores/entire preparation, to moderate = 34 hypnospores/entire preparation). Conclusions. Perkinsus sp. is reported for the first time in a wild population of M. squalida in the southesternmost Gulf of California. The results indicate that this protozoan is dispersed intraspecifically and would now, potentially, parasiting a new host in the region.

A Method to Determine Human Skin Heat Capacity Using a Non-Invasive Calorimetric Sensor.

A calorimetric sensor has been designed to measure the heat flow dissipated by a 2 x 2 cm2 skin surface. In this work, a non-invasive method is proposed to determine the heat capacity and thermal conductance of the area of skin where the measurement is made. The method consists of programming a linear variation of the temperature of the sensor thermostat during its application to the skin. The sensor is modelled as a two-inputs and two-outputs system. The inputs are 1) the power dissipated by the skin and transmitted by conduction to the sensor, and 2) the power dissipated in the sensor thermostat to maintain the programmed temperature. The outputs are 1) the calorimetric signal and 2) the thermostat temperature. The proposed method consists of a sensor modelling that allows the heat capacity of the element where dissipation takes place (the skin) to be identified, and the transfer functions (TF) that link the inputs and outputs are constructed from its value. These TFs allow the determination of the heat flow dissipated by the surface of the human body as a function of the temperature of the sensor thermostat. Furthermore, as this variation in heat flow is linear, we define and determine an equivalent thermal resistance of the skin in the measured area. The method is validated with a simulation and with experimental measurements on the surface of the human body.