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Purpose: The Endoscopic Surgical Skill Quantification System for qualified surgeons (QSs) was introduced in Japan to improve surgical outcomes. This study reviewed the surgical outcomes after initial experience performing laparoscopic distal gastrectomy (LDG) and evaluated the improvement in surgical outcomes following accreditation as a QS. Methods: Eighty-seven consecutive patients who underwent LDG for gastric cancer by a single surgeon were enrolled in this study. The cumulative sum method was used to analyze the learning curve for LDG. The surgical outcomes were evaluated according to the two phases of the learning curve (learning period vs. mastery period) and accreditation (non-QS period vs. QS period). Results: The learning period for LDG was 48 cases. Accreditation was approved at the 67th case. The operation time and estimated blood loss were significantly reduced in the QS period compared to the non-QS period (230 vs. 270 min, p Conclusions: Experience performing approximately 50 cases is required to reach proficiency in LDG. After receiving accreditation as a QS, the surgical outcomes, including the complication rate, were improved.

Adsorption cycles have been gaining significant interest in waste-heat recovery and renewable energy utilization. Adsorption isotherm data and the equilibrium cycle analysis are crucial steps in evaluating a typical adsorbent + adsorbate pair. In this paper, the performance of Maxsorb III + R245fa and spherical activated carbon, SAC-2 + R245fa were studied for adsorption cooling and adsorption heat transformer (AHT) cycles. Adsorption isotherms of these pairs were measured using the constant-volume-variable-pressure apparatus for temperatures ranging from 30 °C to 60 °C, and fitted with the Dubinin–Astakhov (D–A) and the Toth isotherm model. An improved equilibrium model was developed, accounting the effects of thermal masses. The specific cooling energy (SCE) and the coefficient of performance (COP) of the adsorption cooling cycle were evaluated for various thermal mass to adsorbent mass ratios. It is observed that SAC-2 + R245fa pair offers better SCEs (20 kJ kg−1and 160 kJ kg−1 at 60 °C and 90 °C, respectively) when compared to that of Maxsorb III + R245fa. The impact of thermal mass is found to be significant for all regeneration temperatures for Maxsorb III + R245fa while the deterioration of COP in SAC-2 + R245fa is notable for high regeneration temperatures (> 75 °C). When employed in the AHT cycle, Maxsorb III offers a slightly higher useful heat while SAC-2 provides a better Q u h / Q Q R albeit by a small margin. The Q u h / Q Q R values for both studied pairs are more than 0.6 for all regeneration temperatures for the heat extraction at 120 °C.

R410a will remain a common refrigerant in developing nations, even though its high environmental impact assures its eventual phase out. In the hopes of tackling the afore mentioned and identifying potential areas of improvement, the performance of a 2.0 kW chiller is evaluated. The first law of thermodynamics highlights the disadvantage of overcharging the refrigerant amount and the second law applied through an exergy approach points to the compressor as the largest contributor to exergy destroyed and its effects on reducing condenser performance as well. This analysis can be directly compared with alternative refrigerants to replace R410a in the future.

Domestic heat pumps constitute a significant part of the global heat pump industry. R401A offers excellent performance with no influence on the ozone depletion and has been a dominant refrigerant in most domestic heat pumps. However, R410A has a significant impact on the climate due to its high global warming potential (GWP). Thus, the heat pump industry has been focusing on the development of R410A substitutes. Pure refrigerant alternates, such as HFC32, and the blends mixed with low-GWP refrigerants, such as HFO1234yf and HFO1234ze(E), are widely reported. Besides the direct impact of refrigerants (which is estimated as GWP), domestic heat pumps indirectly affect the environment from the energy consumption and manufacturing processes. Hence the life cycle climate performance (LCCP) analysis accounts for all emissions through the lifetime of a heat pump. This article reports the LCCP evaluation of various low-GWP refrigerants for R410A replacement on domestic heat pumps. Six refrigerants, i.e., HFC32, binary blends of HFC32 and HFO1234yf (with GWP values of 300, 200 and 150), and HFC32 and HFO1234ze(E) with GWP values of 300 and 200, were compared against R410A. The performance data of these refrigerants from the experimental heat pump facility were utilized to evaluate the LCCP. Among the selected refrigerants, the binary blend of HFC32/HFO1234ze(E) with GWP 300 shows the lowest LCCP. Low-GWP refrigerants would become more competitive than R410A when CO2 emission from energy generations can be reduced by the optimization of the system or the usage of renewable energy.

Research trends in the heat pump systems can mainly be categorized into the developments of the cycle and the working fluids. Regional and global watchdogs regulate the fate of working fluids in the name of environmental issues, especially global warming. Examples include the Montreal Protocol, the Kyoto protocol, and lately, the European “F Gas” Directive (No. 542/2006). The urgent and pressing call is next-generation refrigerants that are benign to the environment without compromising the performance. Pure substances are known to be limited, while refrigerant mixtures have been gaining significant attention due to their flexibility in tuning flammability, stability, and low GWP values. In this work, we investigated a ternary mixture of HFC-32/HFO-1234yf/R744 (22/72/6mass%) with the targeted GWP less than 150. Three operation modes (cooling for summer, Cooling, low-temperature heating, Heating#1, and high-temperature heating, Heating#2 for winter) were investigated experimentally. Optimal refrigerant charge amounts for all operation modes followed by the system performance were evaluated from part-load to full-load operations. The system is further scrutinized using the 2nd Law of Thermodynamics by tracking exergy destructions in major components. Among the selected operation modes, Heating#1 provides the highest system COPs for all loads due to the lower lift and smaller temperature difference between the inlet and outlet of the coolant to the condenser. The cycle exergetic efficiencies were 31.7%, 37.8%, and 43.3% for Cooling, Heating#1, and Heating#2 modes, respectively. The results presented in this work will be useful in the refrigerant design (ternary mixtures) and the system development for low-GWP refrigerant applications.

Countermeasures for global warming have been promoted internationally. Heat pump cycles that utilize refrigerants with high global warming potential values are required to adopt the next generation...

The urge to replace hydrofluorocarbons which possess high global warming potentials has taken center stage in the air conditioning industry due to both international and local policies such as the ...

Background: Body weight loss (BWL) and skeletal muscle loss (SML) are inevitable after gastrectomy for gastric cancer (GC), and can decrease patients’ quality of life (QOL) and survival. The aim of this retrospective study was to evaluate the effect of perioperative and post-discharge patient participation in continuous nutritional counseling (CNC) on post-gastrectomy BWL and SML. Methods: Ninety-three patients with GC who underwent curative gastrectomy between March 2018 and July 2019 were analyzed. Patients received either pre-discharge nutritional counseling alone (control group, n=49) or patient-participation CNC (CNC group, n=44) after gastrectomy. Difference between percentage BWL (%BWL), percentage SML (%SML), and nutrition-related blood parameters between the preoperative values and those at 12 months after surgery were compared between the groups. Results: Compared with the control group, %BWL was significantly lower in the CNC group at 1 month (–6.2±2.5% vs. –7.9±3.3%, p=0.005), 6 months (–7.8±6.6% vs. –12.3±6.4%, p=0.001) and 12 months (–7.9±7.6% vs. –13.2±8.2%, p=0.002); and %SML was significantly lower in the CNC group at 12 months (–5.3±10.3% vs. –12.8±12%, p=0.002). Regarding nutrition-related blood parameters, change in total cholesterol was significantly lower in the CNC group than the control group at 12 months after surgery (p=0.02). Multivariate analysis identified no CNC as an independent risk factor for severe BWL (p = 0.001) and SML (p = 0.006) at 12 months after surgery. Conclusions: Following gastrectomy, patient-participation CNC prevented postoperative BWL and SML after surgery. These results support the induction of such a CNC program in these patients.

Background Chylous ascites (CA) is a rare complication of gastrectomy for gastric cancer. While most cases of postoperative CA improve with medication or nutritional support, some are refractory to conservative treatment. A peritoneovenous shunt (PVS) may help patients who are poor candidates for surgery. However, PVS placement for postoperative CA after gastroenterological surgery has been rarely reported. Herein, we present a case of postoperative CA following total gastrectomy with para-aortic lymphadenectomy, treated successfully by PVS placement. Case presentation A 74-year-old man who underwent total gastrectomy with para-aortic lymph node dissection was hospitalised because of insufficient oral intake and dehydration. His abdomen was markedly distended with severe bilateral lower extremity oedema. On admission, abdominal computed tomography (CT) showed a high volume of ascites and no signs of cancer recurrence. Accordingly, postoperative CA resulting from drainage of fluid on paracentesis was diagnosed. Despite nutritional support, diuretics, and octreotide administration, his abdominal distension and nutritional status did not improve. We could not identify the sites of lymphatic leakage in the three intranodal lymphangiographies followed by CT. Although we considered a surgical treatment in our patient, we decided against it. Because we could not identify lymphatic leakage site during lymphangiography, surgical treatment might have a potential failure of detection and closure of leakage site. Furthermore, the patient’s general condition was poor because of malnutrition resulting from the loss of lymphatic fluid. Consequently, we decided to place PVS. After PVS placement, his abdominal distension improved rapidly, and he was discharged without serious complications. Thirteen months after PVS, patient has no relapse of abdominal distention and nutrition status has improved. Conclusion PVS might be a good option to manage refractory postoperative CA, as the leakage point cannot be detected on lymphangiography.

Postoperative body weight loss (BWL) and skeletal muscle loss (SML) after gastrectomy are associated with a decline in quality of life and worse longterm prognosis in gastric cancer (GC) patients. This study aimed to evaluate the efficacy of amino acids nutrition on BWL and SML in the early period following gastrectomy.The parameters of body composition were measured by bioelectrical impedance analysis in the patients undergoing radical gastrectomy for GC and analyzed retrospectively. Patients received either peripheral parenteral nutrition (PPN) of 4.3% glucose fluid with regular diet (control group, n=43) or PPN of 7.5% glucose fluid containing amino acids plus oral nutritional supplement (ONS) rich in protein with regular diet (amino acids group, n=40) following gastrectomy. The percentages of BWL and SML from preoperative values to those at 7 days and 1 month after surgery were compared between the two groups.The %BWL and %SML at 7 days after surgery were significantly lower in the amino acids group than those in the control group (%BWL, -2.4±1.7% vs. -4.2±1.8%; p0.0001, %SML, -4.1±3.8 vs. -6.5±3.8; p=0.006). Moreover, the %BWL at 1 month after surgery was significantly lower in the amino acids group compared to that in the control group (- 4.6±2.9% vs. -6.1±2.6%; p=0.01); however, the %SML was similar between the two groups. The hematological nutritional parameters were similar between the two groups.Amino acids nutrition by PPN and ONS following gastrectomy prevented postoperative BWL and SML in the early period after surgery in GC patients.

We present the case of a Tailgut cyst occurring in the retrorectal space that was curatively resected using a posterior approach. A 40-year-old man presented to the Kochi Health Sciences Center with the chief complaint of perineal incongruity. Pelvic magnetic resonance imaging revealed a multilocular cystic lesion in the retrorectal space, with high signal intensity on T2-weighted imaging. After diagnosing a Tailgut cyst, we performed resection of the tumor using a posterior approach. The lesion was removed en bloc with the coccyx. Histopathologically, the lesion was diagnosed as a non-malignant Tailgut cyst, and the surgical margin was negative. The patient is currently doing well without recurrence at 20 months.

This article presents an experimental assessment of coefficient of performance and irreversible loss in the heat pump cycle using hydro-fluoro-olefin base ternary mixtures: YF300 (R744/R32/R1234yf; 4/44/52 mass%), YF200 (R744/R32/R1234yf; 5/28/67 mass%), ZE300 (R744/R32/R1234ze(E); 4/43/53 mass%), and ZE200 (R744/R32/R1234ze(E); 9/29/62 mass%). The smaller volumetric capacity of YF200 and ZE200 increases the irreversible loss caused by the pressure drop with increasing heat load. ZE200, which has a temperature glide of approximately 22 K, increases the irreversible loss in the condenser, evaporator, and expansion valve. The experimental results indicate that YF300 and ZE300 could be potential alternatives to R410A and R32., Science and Technology for the Built Environment, 22(8), pp.1118-1127; 2016

Refrigeration and air-conditioning systems become an integral part of modern society. Electricity-driven vapour compression systems have been dominating the heating, ventilation, air conditioning and refrigeration (HVACR Heating#1 and Heating#2 at different condensing temperatures. The performance of the current binary refrigerant was compared with those of target refrigerants, i.e., R410A, HFC32 and the binary mixture of HFC32/HFO1234yf (22/78 mass%, GWP = ~300) for part- and full-load operations. Experimental results showed that the performance of the present refrigerant is comparable with R410A and HFC32 for high condensing temperatures, especially at part-load operations. The system COP of the current binary blend exhibits from 6 to 14% drop as compared to that of R410A. A significant increase in the system irreversibility losses was observed with the increasing percentage of HFO1234yf. Despite the relatively low performance, the GWP of the present refrigerant is below 150, and it can be used in the existing systems without significant hardware changes while meeting tighter environmental regulations.

Low global warming potential refrigerants R1234ze(E) and R1234ze(Z) are anticipated to be the refrigerants of choice for high-temperature heat pump systems in industrial applications. Their thermodynamic attributes are thermodynamically, experimentally, and numerically assessed in this study. The thermodynamic assessment indicates that the theoretical coefficients of performances (COP) are maximized at a condensation temperature approximately 20 K below the critical temperatures for each refrigerant. However, when the volumetric capacity is inadequate, the actual COP differs from the theoretical COP because of the large pressure drop. The breakdown of irreversible losses, which are experimentally quantified at a condensation temperature of 75 °C, results in the largest portion of the total pressure drop. The simulation results obtained at condensation temperatures of 105 and 125 °C indicate higher COPs than that at 75 °C for R1234ze(Z). The major factor is the reduction in the irreversible loss caused by the pressure drop. The above assessments demonstrate that R1234ze(Z) is suitable for high-temperature applications rather than in typical air conditioners.

症例は45歳，男性．黄疸，発熱を主訴に来院．臍部を中心に巨大な腫瘤を触知し，高度な白血球増多および貧血，閉塞性黄疸を認めた．肝外胆管閉塞を伴う膵頭部～十二指腸下行脚の巨大腫瘍で，生検で上皮系の未分化な悪性腫瘍と診断された．慢性骨髄性白血病の腫瘤形成型急性転化も考えたが骨髄穿刺やNAPスコアは正常で，十二指腸もしくは膵頭部原発の悪性腫瘍を考えSSPPDを行った．膵頭部～十二指腸内を占める巨大な腫瘍で膵外に突出し，膵内胆管および十二指腸に直接浸潤していた．病理所見は退形成性膵管癌で免疫染色で一部G-CSFが陽性であり，白血球数著増と併せG-CSF産生性退形成性膵癌と診断した．術後は約2カ月で肝転移，大動脈周囲リンパ節転移が出現，術後約9カ月で死亡した．

This paper describes experimental results that show the effects of mass velocity and condensation temperature difference on the local heat transfer characteristics during condensation of R407C in a horizontal microfin tube. The experiments were performed at the saturation temperature of 40 °C, the refrigerant mass velocity of 50, 100, 200 and 300 kg m −2 s −1 , and the condensation temperature difference of 1.5, 2.5 and 4.5 K. A superficial heat transfer coefficient for the vapor phase was obtained by subtracting the heat transfer resistance of condensate film estimated by using a previously developed theoretical model of film condensation of pure vapor from the overall heat transfer resistance. On the basis of the analogy between heat and mass transfer, an empirical equation for the superficial vapor phase heat transfer coefficient was developed. The heat transfer coefficient predicted by the combination of the previously developed theoretical model of film condensation of pure vapor and the empirical equation of the superficial vapor phase heat transfer coefficient agreed with the measured values with the r.m.s. error of 9.2%.

Experiments were conducted to study the flow and heat transfer characteristics of a natural circulation liquid cooling system for electronic components. The test loop consisted of a horizontal test section, a horizontal evaporator, a vertical tube, a horizontal condenser, a rubber bag attached at the exit of the condenser, a downcomer, a mass flow meter, and a liquid subcooler. The loop height H was set at either 250 or 450 mm. FC-72 was filled in the test loop up to some level of loop height and the upper part was filled with air. During the operation of the cooling system, the rubber bag expanded and stored the mixture of generated vapor and air. Thus the inner pressure was maintained at atmospheric pressure. In the test section, a silicon chip with dimensions of 10×10×0.5 mm3 was attached at the bottom surface of a horizontal duct with dimensions of 10×14 mm2. A smooth chip and four chips with square micro-pin-fins with 150 to 300 μm in fin height were tested. The duct height s was set at 10 mm for most of the experiments. The cases of s=1 and 25 mm were also tested for one of the micro-pin-finned chips. For each H, the average flow rate of FC-72 was correlated well as a function of the static pressure difference between the two vertical tubes. All chips showed the boiling curve similar to that for pool boiling except that the critical heat flux was lower for the natural circulation loop. For all chips tested, the maximum allowable heat flux qmax increased monotonically with increasing liquid subcooling ΔTsub. Comparison of the results for s=1, 10 and 25 mm revealed that the highest qmax was obtained with s=10 mm. The values of qmax for s=1 and 25 mm were 36–46% and 87–90% of that for s=10 mm, respectively. The maximum value of qmax=56 W/cm2 was obtained by one of the micro-pin-finned chips at s=10 mm and ΔTsub=35 K.

Experiments were conducted to study the flow and heat transfer characteristics of a natural circulation cooling system for electronic components. The test loop consisted of a horizontal test section, a horizontal evaporator, a vertical tube, a horizontal condenser, a rubber bag attached at the exit of condenser, a downcomer, a mass flow meter, and a liquid cooler. The loop height H was set at 250 and 450 mm. In the test section, a silicon chip with dimensions of 10×10×0.5 mm3 was attached at the bottom of a horizontal duct with dimensions of 10×14 mm2.A smooth chip and five chips with square micro-pin-fins were tested. For each H, the average flow rate of FC-72 was correlated well as a function of the static head difference between the two vertical tubes. The heat transfer results were compared with those for pool boiling.All chips showed the boiling curve similar to the case of pool boiling except that the critical heat flux was about 20% lower than that for pool boiling.

Heat and mass transfer in a falling film vertical in-tube absorber was studied experimentally with LiBr aqueous solution. The presented results include the effect of solution flow rate, solution subcooling and cooling water temperature on the absorption in a smooth copper tube 16.05 mm I.D. and 400 mm long. The experimental data in the previous report for a 1200-mm-long tube was also re-examined and compared. It was demonstrated by the observation of the flow in the tube that the break down of the liquid film into rivulets leads to deterioration of heat and mass transfer at lower film Reynolds number or in longer tubes. An attempt to evaluate physically acceptable heat and mass transfer coefficients that are defined with estimated temperature and concentration at the vapor–liquid interface was also presented.

Experimental results are presented that show the effect of fin geometry on condensation of downward flowing zeotropic refrigerant mixture R407C in a staggered bundle of horizontal finned tubes. Two types of conventional low-fin tubes and three types of three-dimensional-fin tubes were tested. The refrigerant mass velocity ranged from 4 to 23 kg/m2 s and the condensation temperature difference from 3 to 12 K. The measured condensation heat transfer coefficient was lower than the previous results for R134a, with the difference being more significant for smaller mass velocity. The effect of fin geometry on the condensation heat transfer coefficient was less significant for R407C than for R134a. The effect of condensate inundation was more significant for the three-dimensional-fin tubes than for the low-fin tubes. By using the dimensionless heat transfer correlation for the condensate film that was based on the experimental data for R134a, a superficial vapor-phase heat transfer coefficient was obtained for condensation of R407C. The vapor-phase heat transfer coefficient showed characteristics similar to the vapor-phase mass transfer coefficient that was obtained in the previous study for R123/R134a.

Experimental results are presented that show the effect of fin geometry on condensation of refrigerant HFC134a in a staggered bundle of horizontal finned tubes. Two types of conventional low-fin tubes and three types of three-dimensional fin tubes were tested. The refrigerant mass velocity ranged from 8 to 23 kg/m2s and the condensation temperature difference from 1.5 to 12 K. The effect of condensate inundation was more significant for the three-dimensional fin tubes than for the low-fin tubes. In most cases, the highest performance was obtained by the tube with a three-dimensional structure at the tip of low fins. In the case of high mass velocity and high condensate inundation rate, however, the highest performance was obtained by one of the low-fin tubes. The results were compared with previous results for bundles of smooth tubes and low-fin tubes.

Experiments were conducted to obtain row-by-row heat and mass transfer data during condensation of downward-flowing zeotropic mixture R123/R134a in a staggered bundle of horizontal low-finned tubes. The vapor temperature and the mass fraction of R134a at the tube bundle inlet were about 50°C and 14%, respectively. The refrigerant mass velocity ranged from 9 to 34 kg m−2 s−1, and the condensation temperature difference from 1.9 to 12 K. Four kinds of low-finned tubes with different fin geometry were tested. The highest heat transfer coefficient was obtained with a tube which showed the highest performance for R123. However, the diference among the tubes was much smaller for the mixture than for R123. The heat transfer coefficient and the vapor-phase mass transfer coefficient decreased significantly with decreasing mass velocity. The mass transfer coefficient increased with condensation temperature difference, which was due to the effect of suction associated with condensation. On the basis of the analogy between heat and mass transfer, a dimensionless correlation of the mass transfer coefficient was developed for each tube.

Experiments were conducted to obtain row-by-row heat transfer data during condensation of downward-flowing zeotropic refrigerant mixture HCFC-123/HFC-134a on a 3 × 75 (columns × rows) staggered bundle of horizontal low-finned tubes. The vapor temperature and the HFC-134a mass fraction at the tube bundle inlet were maintained at about 50°C and nine percent, respectively. The refrigerant mass velocity ranged from 9 to 34 kg/m2 s, and the condensation temperature difference from 3 to 12 K. The measured distribution of the vapor mass fraction in the tube bundle agreed fairly well with that of the equilibrium vapor mass fraction. The vapor phase mass transfer coefficient was obtained from the heat transfer data by subtracting the thermal resistance of the condensate film. The heat transfer coefficient and the mass transfer coefficient decreased significantly with decreasing mass velocity. These values first increased with the row number up to the third (or second) row, then decreased monotonically with further increasing row number, and then increased again at the last row. The mass transfer coefficient increased with condensation temperature difference, which was due to the effect of suction associated with condensation. On the basis of the analogy between heat and mass transfer, a dimensionless correlation of the mass transfer coefficient for the 4th to 14th rows was developed.