The present study proposes a method to predict the burst pressures (BPs) of type III filament winding carbon fiber-reinforced plastic (CFRP) composite pressure vessels considering the inhomogeneity ...of carbon fiber packing through experimental work and simplified mechanical models reflecting the evolution of local damage in the CFRP layers. Vessels that had different carbon fiber volume fractions (Vfs) were prepared and tested to measure their BPs. The inhomogeneity of carbon fiber packing was evaluated using Weibull probability based on the microscopic observation of CFRP cross-sections in the virgin vessels. Detailed stress analyses of pressurized composite vessels considering the carbon Vf were conducted. Unstable fracture of the hoop layer was demonstrated by a simplified mechanical model combined with the inhomogeneity of the carbon Vf and de-bonding between the fiber and matrix. About 20% difference in the BP was measured between tested vessels with and without glass fiber-reinforced plastic layers over CFRP layers. The proposed method for predicting the BP based on the constant stress model enables consideration of the development of local fiber breaking prior to catastrophic fracture and to quantitatively estimate the change in the BP due to the difference in Vf.
Purpose
To evaluate the effectiveness and safety of a new trifocal intraocular lens (IOL) after cataract removal in patients living in Japan.
Study design
Prospective multicenter clinical study.
...Methods
One hundred and thirty-five eyes of 68 patients (19 men, 49 women; mean age, 66.3 ± 7.4 years) were followed for 6 months. Trifocal IOLs with focal points at near, intermediate, and distance were implanted bilaterally in eyes with less than 1 diopter of corneal astigmatism. The visual acuity (VA) at distance, 60 and 40 centimeters (cm), and contrast sensitivities were measured. Patients completed quality-of-life questionnaires preoperatively and postoperatively.
Results
The mean bilateral logarithm of the minimum angle of resolution VA at 5 meters (m), 60 cm, and 40 cm were, respectively: uncorrected, − 0.104 ± 0.095, − 0.065 ± 0.111, and − 0.042 ± 0.105; and distance-corrected, − 0.197 ± 0.076, − 0.112 ± 0.111, and − 0.073 ± 0.111. The contrast sensitivities at distance and near were within the normal range at all spatial frequencies under photopic conditions. Patients reported complete spectacle independence in 75.0% of cases. Total use of spectacles was reported by 1.5% and partial by 20.6%; the purpose of spectacle use was primarily for near visual tasks. Mild-to-moderate glare was reported by 65.7% of patients and halos by 70.1%; only 1.5% of subjects reported severe glare and halos.
Conclusions
This new trifocal IOL provides equally good uncorrected VAs at distance, intermediate, and near, and decreases spectacle dependence in daily life. Patients frequently report mild-to-moderate glare and halos, and patients should be informed about these before implantation.
Background
Several studies have demonstrated that prehabilitation helps reduce the incidence of postoperative complications. In this study, we investigated the safety and efficacy of enhanced ...prehabilitation (EP) in the hospital for patients with esophageal cancer.
Methods
We retrospectively reviewed the data of 48 consecutive patients who underwent radical esophagectomy with gastric tube reconstruction between September 2015 and June 2019. EP program had been introduced in August 2017. In the EP group, patients received the EP program during hospitalization 7 days before surgery in addition to conventional perioperative rehabilitation. The EP program consisted of aerobic exercise and muscle strength training in the morning and afternoon. Operative outcomes were compared between patients who received EP (EP group; 23 patients) and patients who did not receive EP (control group; 25 patients).
Results
The preoperative (EP group vs. control group, 492.9 ± 79.7 vs. 418.9 ± 71.8 m,
p
< 0.001) and postoperative (EP group vs. control group, 431.5 ± 80 vs. 378 ± 68.7 m,
p
< 0.001) 6-min walk distance was significantly higher in the EP group than in the control group. The respiratory complications rate was significantly lower in the EP group (4.3%) than in the control group (36%) (
p
= 0.007). The incidence of atelectasis was particularly significantly lower in the EP group (0%) than in the control group (24%) (
p
= 0.012).
Conclusions
EP was performed safely for patients before esophagectomy. EP improved the exercise tolerance of the patients before esophagectomy and might be useful in preventing respiratory complications.
Purpose. To evaluate delivery performance of an automated preloaded intraocular lens (IOL) injector systems (AutonoMe) in the porcine eyes. Methods. In the freshly excised porcine eyes, lens removal ...and IOL implantation were performed. There were 4 groups (10 eyes per group) with different incision site and size: 2.2-mm and 2.4-mm corneal incisions and 2.2-mm and 2.4-mm sclerocorneal incisions. Delivery performance and wound enlargement of AutonoMe were analyzed and compared with those of iTec and iSert from a previous study. Results. There were a few minor troubles associated with AutonoMe, such as overriding plunger within cartridge and trapped trailing haptic during IOL insertion, but the incidence was low. Other interactions were not observed, such as IOL adherence to plunger, sudden ejection of IOL, intrawound lens manipulation, IOL behavior, and gross damage to IOL. AutonoMe caused significantly less wound enlargement for both corneal and sclerocorneal incisions than other injector devices. Wound enlargement by using AutonoMe was significantly smaller with 2.4-mm corneal incision than with 2.2-mm corneal incision, but the final incision size was still smaller with 2.2-mm corneal incision. For sclerocorneal incisions, the amount of wound stretch was not different between 2.2 and 2.4 mm incisions. Conclusion. The wound enlargement caused by the automated preloaded insertion system, AutonoMe, was smaller than that of other preloaded injectors for both corneal and sclerocorneal incisions. There were a few minor technical events during IOL insertion, but the overall incidence was low.
Circulating tumor DNA (ctDNA) is released from tumor cells into blood in advanced cancer patients. Although gene mutations in individual tumors can be diverse and heterogenous, ctDNA has the ...potential to provide comprehensive biomarker information. Here, we performed multi-region sampling (three sites) per resected specimen from 10 gastric cancer patients followed by targeted sequencing and proteomic profiling using reverse-phase protein arrays. A total of 126 non-synonymous mutations were identified from 30 samples from 10 tumors. Of these, 16 (12.7%) were present in all three regions and were designated as founder mutations. Variant allele frequencies (VAFs) of founder mutations were significantly higher than those of non-founder mutations. Phylogenetic analysis also demonstrated a good concordance between founder and truncal mutations, defined as mutations shared by all simulated clones at the trunk of the tumor phylogenetic tree. These findings led us to prioritize founder mutations for quantitative ctDNA monitoring by digital PCR with individually-designed primer/probe sets. In preoperative plasma, the average ctDNA VAF of founder mutations was significantly higher than that of non-founder mutations (p = 0.039). Proteomic heterogeneity was present across the tumor regions both within and between patients independent of mutational status. Our results suggest that, in practice, mutations having high VAF identified without multi-regional sequencing may be immediately useful for quantitative ctDNA monitoring but do not provide sufficient information to predict the proteomic composition of tumors.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Purpose
To assess the efficacy and safety of filtration surgery using the EX-PRESS glaucoma filtration device in patients with normal-tension glaucoma (NTG).
Study design
Prospective, single-arm, ...multicenter interventional case series.
Methods
Eyes with NTG underwent EX-PRESS implantation with or without cataract surgery. The efficacy and safety were assessed at 1 day; 1 and 2 weeks; and 1, 3, 6, and 12 months after surgery. The main outcome measure was reduction in intraocular pressure (IOP) from baseline at 3, 6, and 12 months after surgery. Safety assessments included adverse event incidence, postoperative inflammation, and corneal endothelial cell density.
Results
Thirty-two Japanese patients (37 eyes) with NTG were enrolled. The mean IOP decreased from 14.8 ± 2.3 mmHg at baseline to 10.0 ± 3.1 mmHg at 12 months after surgery (mean reduction 4.9 ± 4.2 mmHg 31.1%;
P
< .0001). IOP-lowering medication use decreased from a mean of 3.3 medications per eye before surgery to 0.1 medications per eye at 12 months after surgery. IOP reductions > 20% were achieved by 61.5% of the eyes at 12 months. Adverse events were typical for filtration procedures, and none was deemed device-related. Postoperative inflammation was mild and self-limiting. The mean corneal endothelial cell density had decreased by 3.3% at 12 months after surgery.
Conclusion
The EX-PRESS glaucoma filtration device is safe and effective for filtration surgery in patients with NTG, providing mean IOP reduction consistent with recommendations based on the Collaborative NTG Study.
Pylorus-preserving gastrectomy (PPG) has been accepted as a function-preserving surgery for the treatment of early gastric cancer in East Asian countries. Therefore, this study aimed to evaluate the ...feasibility and safety of totally laparoscopic PPG (TLPPG) with intracorporeal anastomosis.
A total of 43 patients with early gastric cancer underwent laparoscopy-assisted PPG (LAPPG) with extracorporeal anastomosis between May 2006 and November 2012. The operative outcomes of 22 patients who underwent TLPPG between November 2012 and February 2019 were evaluated, and data were compared with that of the LAPPG group.
No significant difference in the operative time was observed between the two groups. Blood loss was lower in the TLPPG group (18.5 mL) than in the LAPPG group (30.7 mL, p = 0.008), and the length of abdominal incision was shorter in the TLPPG group (3.8 cm) than in the LAPPG group (4.7 cm, p < 0.001). No significant difference in the complication rate was observed between the two groups (13.6% in the TLPPG vs. 9.3% in the LAPPG group, p = 0.594). No anastomosis-related complications occurred in either group. No significant between-group difference was observed in the delayed gastric emptying (TLPPG, 9.1 vs. LAPPG, 7%, p = 0.762). The initiation of postoperative fluid (TLPPG, 1.0 day vs. LAPPG, 3.0 days, p < 0.001) and meal (TLPPG, 3.0 days vs. LAPPG, 4.0 days, p < 0.001) intake was earlier in the TLPPG group than in the LAPPG group. No significant between-group difference was observed in the postoperative hospital stay.
The findings of this study suggest that TLPPG with intracorporeal reconstruction not only is as feasible and safe as LAPPG for the treatment of patients with early gastric cancer but also provides certain advantages such as reduced blood loss and wound size.
This paper presents an investigation on the scale effects associated with the powering performance of a Gate Rudder System (GRS) which was recently introduced as a novel energy-saving propulsion and ...maneuvring device. This new system was applied for the first time on a 2400 GT domestic container ship, and full-scale sea trials were conducted successfully in Japan, in 2017. The trials confirmed the superior powering and maneuvring performance of this novel system. However, a significant discrepancy was also noticed between the model test-based performance predictions and the full-scale measurements. The discrepancy was in the power-speed data and also in the maneuvring test data when these data were compared with the data of her sister container ship which was equipped with a conventional flap rudder. Twelve months after the delivery of the vessel with the gate rudder system, the voyage data revealed a surprisingly more significant difference in the powering performance based on the voyage data. The aim of this paper, therefore, is to take a further step towards an improved estimation of the powering performance of ships with a GRS with a specific emphasis on the scale effect issues associated with a GRS. More specifically, this study investigated the scale effects on the powering performance of a gate rudder system based on the analyses of the data from two tank tests and full-scale trials with the above-mentioned sister ships. The study focused on the corrections for the scale effects, which were believed to be associated with the drag and lift characteristics of the gate rudder blades due to the low Reynolds number experienced in model tests combined with the unique arrangement of this rudder and propulsion system. Based on the appropriate semi-empirical approaches that support model test and full-scale data, this study verified the scale effect phenomenon and presented the associated correction procedure. Also, this study presented an enhanced methodology for the powering performance prediction of a ship driven by a GRS implementing the proposed scale effect correction. The predicted powering performance of the subject container vessel with the GRS presented an excellent agreement with the full-scale trials data justifying the claimed scale effect and associated correction procedure, as well as the proposed enhanced methodology for the practical way of predicting the powering performance of a ship with the GRS.
This study aims to demonstrate the merits of pressure-relieving holes at the tip region of propellers, which is introduced as “PressurePoresTM” technology as a retrofit on marine propellers to ...mitigate tip vortex cavitation noise for a quieter propeller. Shipping noise originates from various sources on board a vessel, amongst which the propeller cavitation is considered to dominate the overall radiated noise spectrum above the inception threshold. Thus, by strategically introducing pressure-relieving holes to modify the presence of cavitation, a reduction in the overall cavitation volume can be achieved. This mitigation technique could consequently result in a reduction of the radiated noise levels while maintaining the design efficiency as much as possible or with the least compromise. The strategic implementation of the holes was mainly aimed to reduce the tip vortex cavitation as this is one of the major contributors to the underwater noise emissions of a ship. In this paper, the details and results of a complementary numerical and experimental investigation is presented to further develop this mitigation concept for underwater radiated noise (URN) and to validate its effectiveness at model scale using a research vessel propeller. An overall finding from this study indicated that a significant reduction in cavitation noise could be achieved (up to 17 dB) at design speed with a favourable strategic arrangement of the pressure pores. Such a reduction was particularly evident in the frequency regions of utmost importance for marine fauna while the propeller lost only 2% of its efficiency.
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