Testing thermal comfort of trekking boots: an objective and subjective evaluation

The study of the thermal comfort of the feet when using a specific type of shoe is of paramount importance, in particular if the main goal of the study is to attend to the needs of users. The main aim of this study was to propose a test battery for thermal comfort analysis and to apply it to the analysis of trekking boots. Methodologically, the project involves both objective and subjective evaluations. An objective evaluation of the thermal properties of the fabrics used in the boots was developed and applied. In addition, the thermal comfort provided when using the boots was also assessed both subjective and objectively. The evaluation of the thermal comfort during use, which was simulated in a laboratory environment, included the measurement of the temperature and moisture of the feet. The subjective assessment was performed using a questionnaire. From the results obtained, it was possible to define an optimal combination of fabrics to apply to trekking boots by considering the provided thermal insulation, air permeability and wicking. The results also revealed that the subjective perception of thermal comfort appears to be more related to the increase in temperature of the feet than to the moisture retention inside the boot. Although the evaluation of knits used in the boots indicated that a particular combination of fibres was optimal for use in the inner layer, the subjective and objective evaluation of thermal comfort revealed that the evaluation provided by users did not necessarily match the technical assessment data. No correlation was observed between the general comfort and specific thermal comfort assessments. Finally, the identification of thermal discomfort by specific foot areas would be useful in the process of designing and developing boots.

Development of highly sensitive electrochemical sensor using new graphite/acrylonitrile butadiene styrene conductive composite and 3D printing-based alternative fabrication protocol

Here, a novel electrically conductive thermoplastic material composed of graphite/acrylonitrile butadiene styrene (G/ABS) is reported for the first time. This material was explored on the production of 3D printing-based electrochemical sensors with enhanced sensitivity using a novel fabrication approach. The developed G/ABS electrodes showed lower charge transfer resistance (157 vs. 3279 Ω), higher electroactive area (0.61 vs. 0.19 cm²) and peak currents ca. 69% higher when compared with electrodes fabricated using carbon black/polylactic acid (CB/PLA) commercial filament, which has been widely explored in recent literature. Moreover, the G/ABS sensor provided satisfactory repeatability, reproducibility and stability (relative standard deviations (RSDs) were 1.14%, 6.81% and 10.62%, respectively). This improved performance can be attributed to the fabrication protocol developed here, which allows the incorporation of greater amounts of conductive material in the polymeric matrix. The G/ABS electrode also required a simpler and quicker protocol for activation when compared to CB/PLA. As proof of concept, the G/ABS sensor was employed for electroanalytical quantification of paracetamol (PAR) in pharmaceutical products. The linear concentration range was observed from 0.20 to 30 μmol L^-1 and the limit of detection achieved was 54 nmol L^-1, much lower than several recent studies dealing with the same analyte. The sensitivity of the G/ABS electrode regarding PAR was also far better when compared to CB/PLA sensor (0.50 μA/μmol L^-1 vs. 0.12 μA/μmol L^-1). Analyses in commercial pill samples showed good accuracy (recoveries ca. 108%) and precision (RSDs < 5%), suggesting great potential for use of this novel conductive thermoplastic in electroanalytical applications based on 3D printing.

[Hypoinsulinemia in alcoholics with minimal liver disease]

The chronic pancreatitis (CP) may evolve with low insulin levels and develop clinical picture of diabetes mellitus. Low seric levels of insulin and C peptide after stimulus has also been described in asymptomatic alcoholics even with normal glycemic curves. It is known that the chronic alcoholism is the main etiological factor of CP and hepatic diseases, and that the insulin produced by the pancreas is metabolized mainly by the liver. High levels of periferic insulin are described in hepatic cirrhosis due to decrease of hepatic metabolization alone or associated to increase of periferic resistance.

AIM

In alcoholics with minimal hepatic lesions to evaluate the seric insulin and glucose levels after stimulus with intravenous glucose.

METHODS

In 8 alcoholic patients with minimal hepatic lesions characterized by hepatic biopsy, and 26 non-alcoholics, healthy controls, it was studied the serum glucose and insulin levels in basal time, 1, 3, 5, and 10 minutes after stimulus with intravenous glucose (0.5 g/kg).

RESULTS

The insulin means in time 1, 3 minutes and total integrated response after stimulus were lower (p < 0.05) in alcoholic group than in control, even with normal glucose curves.

CONCLUSION

Alcoholics with minimal hepatic lesions showed low seric insulin levels after glucose stimulus, similar to former observations in asymptomatic alcoholics, indicating hypofunction of pancreatic B cells.

Blood glucose and insulin response to intravenous glucose by patients with chronic Chagas' disease and alcoholism

Blood glucose and insulin responses to intravenous glucose 500 mg/kg in a group of alcoholic chagasic patients (Group I, N = 15) were assessed and compared to those of a group of patients with Chagas' disease without alcoholism (Group II, N = 16), a group of alcoholics without Chagas' disease (Group III, N = 22), and a group of non-alcoholics without Chagas' disease (Group IV, N = 15). Determinations of serum glucose and insulin were done under fasting conditions, 5 and 10 min after the injection of 50% glucose. There was no difference in mean serum glucose levels between groups. Mean serum insulin levels at times 5 and 10 min and for the total integrated response were lower (P < 0.05) in Groups I and II as compared to Group IV; at time 10 min the mean was lower (P < 0.05) in Group III as compared to Group IV. There was a nonsignificant trend for a lower insulinemic response in Group I as compared to Group II. These data suggest denervation of or injury to pancreatic B cell by Chagas' disease.

The enteroinsular axis and endocrine pancreatic function in chronic alcohol consumers: evidence for early beta-cell hypofunction

Chronic alcohol consumers may have, as judged by functional criteria, exocrine as well as endocrine pancreatic dysfunction, the latter represented by a decreased insulin response to an oral glucose load. To investigate whether this decreased insulin response was due to an ethanol-induced beta-cell dysfunction or to an ethanol-induced dysfunction of the enteroinsular axis, we determined glucose, insulin, and C-peptide plasma concentrations following an oral and an intravenous glucose load in 16 healthy volunteer nonalcohol consumers and in 10 chronic alcohol consumers. In each group, total integrated response for glucose did not significantly change whether glucose was given orally or intravenously, indicating isoglycemic glucose loads. The total integrated response values for insulin in the alcoholic group following both glucose loads as well as C-peptide plasma concentrations were significantly lower than in the control group. Moreover, in both groups the insulin TIR values following the oral glucose load were significantly greater than the values obtained following the intravenous glucose load, indicating an incretin effect. These results indicate that the decreased insulin response observed in alcoholics was not caused by a dysfunction of the enteroinsular axis because it also occurred following an intravenous glucose load, but by an ethanol-induced beta-cell dysfunction because C-peptide and insulin were proportionally decreased in this group.

[Microcrystals and biliary sludge: pathogenesis and clinical significance]

Review of the literature concerning the pathogenesis and the clinical significance of microcrystals and biliary sludge. In addition, the advantages and limitations of the available methodology of identification of these microscopic precipitates and the clinical conditions in which the investigation of the bile composition, with respect to the presence of cholesterol and calcium bilirubinate microcrystals, are discussed. In conclusion, algorithms for treatment of bileopancreatic diseases caused by microcrystals and/or biliary sludge are proposed.

Exploring the coating of 3D-printed insulating substrates with conductive composites: a simple, cheap and versatile strategy to prepare customized high-performance electrochemical sensors

The development of 3D-printed electrochemical sensors by fused deposition modeling (FDM) has been increasing exponentially in the last five years. In this context, commercial conductive filaments composed of a blend of carbon particles (e.g., graphene or carbon black (CB)) and insulating thermoplastic polymers (e.g., polylactic acid (PLA) or acrylonitrile butadiene styrene (ABS)) have been widely used for electrode fabrication. However, such materials may be expensive and the electrodes when used "as-printed" exhibit poor electrochemical performance as a function of the low content of conductive particles in the composition (∼10 to 20 wt%), which requires one or more post-treatment steps (e.g. polishing, chemical, electrochemical, and photochemical) to reach good electrochemical performance. In this technical note a less used approach to produce "ready-to-use" electrochemical platforms based on 3D printing is explored, which consists of the coating of 3D-printed insulating substrates with homemade conductive composites. To demonstrate the potentiality of this alternative protocol, 3D-printed ABS insulating substrates at two geometries were coated in a highly loaded graphite (55 wt%) homemade composite (G-ABS) and evaluated for the detection of the ferri/ferrocyanide redox probe and model analytes in stationary and hydrodynamic 3D-printed systems (nitrite in micro-flow injection analysis/μFIA and paracetamol in batch injection analysis/BIA, respectively). The analytical parameters acquired with the coated electrodes were comparable to those obtained using conventional electrodes (glassy carbon, boron-doped diamond and carbon screen-printed) and 3D-printed sensors fabricated with commercial filaments. Moreover, the inclusion of carbon black in the fluid conductive composite was demonstrated as a perspective to obtain modified coated 3D-printed surfaces easily for the first time. This alternative "do it yourself" strategy is promising for the large-scale production of very cheap (US$ 0.08) and high-performance electrodes based on FDM 3D printing. Moreover, this approach dispenses the acquisition of commercial conductive filaments and the laborious development of homemade filaments.

Exocrine pancreatic hypersecretion in Brazilian alcoholics

Thirty percent of alcoholic patients without clinical evidence of pancreatic or hepatic disease showed hypersecretion of pancreatic bicarbonate in all three test periods after stimulation with secretin and secretin-cholecystokinin, and an increased amount of protein in the duodenal aspirate of the first test period, probably due to ductal wash-out. This hypersecretion must be taken into account when the secretion or secretin-cholecystokinin tests of alcoholics are interpreted, and, indeed, may be useful in identifying possible early pancreatic dysfunction that precedes insufficiency and clinical symptoms.