呼吸前反馈调节、情景想象和过度通气

通过大量的科学证据 ,我们论述了代谢的负反馈调节不是呼吸调节的唯一机制。醒觉时呼吸的前反馈调节起了主导作用 ,前反馈调节可以在血气异常引起的负反馈调节之前 ,对将要发生的异常进行纠正 ,预见性地改变通气 ,而代谢的变化随后发生 ,避免了负反馈调节所具有的波动和滞后的缺点 ,使呼吸调节系统具有更大的灵活性和适应能力。在前反馈调节的形成过程中 ,经典的巴甫洛夫条件反射学说可能起了重要作用 .尤其重要的是表象作为条件刺激形成的条件反射 ,研究表象作为条件刺激如何形成呼吸的前反馈调节对揭示高通气综合征的发病机制具有重要意义…     

The comparison of high and standard definition computed tomography techniques regarding coronary artery imaging

ObjectiveThe aim was to compare coronary high-definition CT (HDCT) with standard-definition CT (SDCT) angiography as to radiation dose, image quality and accuracy.ResultsThe intraclass correlation coefficient (ICC) of measured vessel attenuation values in SDCT between the two radiologists was exceedingly good. The ICC was higher in HDCT. The radiation dose of HDCT was higher than that of SDCT. The mean tube current was 180 (mA) in HDCT and 147(mA) in SDCT with the same tube voltage (kVp). There was no significant difference between image quality.ConclusionHDCT has a higher radiation dose but has much more atenuation and the spatial resolution which improve measurement accuracy for imaging coronary arteries.     

Urothelial cancer of bladder in young versus older adults: Clinical and pathological characteristics and outcomes

Bladder urothelial carcinoma is rare in young adults and occurs more commonly in older individuals. The aim of this study was to compare the clinical behavior, pathologic characteristics, and prognosis of urothelial carcinoma of urinary bladder in young versus older adults. A retrospective review of our records between 2007 and 2013 identified 56 patients (42 males and 14 females) with transitional cell carcinoma of the bladder who were less than 40 years old. Clinical and pathological parameters of patients who were less than 40 years of age were compared with those of a series of patients older than 40 years of age (the control group) during the same period. A survival analysis was performed using the Kaplan–Meier method and log-rank test, and Cox regression was performed to identify clinical parameters that affected the clinical outcomes. The mean age was 29.21 years (range, 5–40 years) for patients less than 40 years old and 61.66 years (range, 41–75) for those older than 40 years. The mean follow-up was 40.26 months (range, 12–65 months) for young patients and 42.57 months (range, 12–72 months) for the older patients. Young bladder cancer patients had smaller-sized tumors (less than 3 cm), less high-grade cancers, higher papillary urothelial neoplasms of low malignant potential, and low-grade tumors than patients older than 40 years. Multivariate logistic regression analysis predicted tumor recurrence in young patients with high-grade tumors [odds ratio (OR), 1.959; 95% confidence interval (CI), 1.235–2.965; p = 0.046] and tumors larger than 3 cm (OR, 1.772; 95% CI, 1.416–1.942; p = 0.032). The 5-year overall survival rate was 100% for young patients and 88.1% for older patients. No difference was observed in the recurrence-free (p = 0.321) and progression-free (p = 0.422) survival rates between the two groups. We concluded that although the clinical stage distribution, natural history, and outcomes of bladder urothelial cancer in young adults are similar to those in their older counterparts, clinicians must be aware that patients under 40 years of age presented with higher-grade and larger (>3 cm) tumors and are more likely to experience tumor recurrence.     

Effects of polyols on the quality characteristics of sucrose-free milk chocolate produced in a ball mill

Sucrose-free milk chocolates containing different types of bulk (isomalt, xylitol and maltitol) and high intensity (Stevia) sweeteners were produced by using a ball mill. The main quality characteristics of the formulated chocolates were evaluated and compared with those of the conventional sample containing sucrose. The Casson model was the best fitting model for the rheological data. Casson viscosity and Casson yield stress were significantly affected by the type of bulking agent in chocolates formulated with xylitol (p < 0.05). However xylitol notably improved the overall acceptability according to the sensory analysis results. Chocolates containing the sucrose replacers demonstrated lower T_onset values and higher enthalpy than the control sample. Sucrose-free chocolates illustrated a higher degree of particle agglomeration. Bulk sweeteners meanwhile seem to have high potential for milk chocolate production with low calorie values by using the ball mill technique. Industrial applications: the production of sucrose-free chocolates with conventional methods requires a lot of time and energy. Recently, using alternative methods for chocolate production has been raising interest in many small industries. This study proposed a ball mill method for the preparation of sucrose-free milk chocolates with physiochemical properties almost ranging in the standard limit defined for chocolate. Although using the ball mill method presents a more cost-effective technique for chocolate production and provides shorter processing times for small chocolate industries, it seems to be less efficient in evaporating moisture than the conventional processing. Challenges are still ahead for upgrading this alternative technique to be efficient in evaporating more moisture during operation ending in a high quality product.

Sucrose-free milk chocolates containing different types of bulk (isomalt, xylitol and maltitol) and high intensity (Stevia) sweeteners were produced by using a ball mill.     

The influence of covalent and non-covalent functionalization of GNP based nanofluids on its thermophysical,rheological and suspension stability properties

Covalent functionalization (CF-GNPs) and non-covalent functionalization (NCF-GNPs) approaches were applied to prepare graphene nanoplatelets (GNPs). The impact of using four surfactants (SDS, CTAB, Tween-80, and Triton X-100) was studied with four test times (15, 30, 60, and 90 min) and four weight concentrations. The stable thermal conductivity and viscosity were measured as a function of temperature. Fourier transform infrared spectroscopy (FTIR), thermo-gravimetric analysis (TGA), X-ray diffraction (XRD) and Raman spectroscopy verified the fundamental efficient and stable CF. Several techniques, such as dispersion of particle size, FESEM, FETEM, EDX, zeta potential, and UV-vis spectrophotometry, were employed to characterize both the dispersion stability and morphology of functionalized materials. At ultrasonic test time, the highest stability of nanofluids was achieved at 60 min. As a result, the thermal conductivity displayed by CF-GNPs was higher than NCF-GNPs and distilled water. In conclusion, the improvement in thermal conductivity and stability displayed by CF-GNPs was higher than those of NCF-GNPs, while the lowest viscosity was 8% higher than distilled water, and the best thermal conductivity improvement was recorded at 29.2%.

Covalent functionalization (CF-GNPs) and non-covalent functionalization (NCF-GNPs) approaches were applied to prepare graphene nanoplatelets (GNPs).