Maintenance Rate Research Articles

Investigating the working efficiency of natural wastewater treatment systems: A step towards sustainable systems

Abstract Globally, wastewater is a vital resource and requires appropriate treatment management strategies. Wastewater has become a major source of irrigation in the peri-urban areas of developing nations. With the increasing amount of wastewater generation, there are several complications in using treatment systems in terms of installation, operation and maintenance, and size in developing countries. Recently, natural treatment systems are gaining popularity due to less cost and maintenance and have been preferred in peri-urban settings. In this study, the working efficiency of the natural systems was assessed from case studies from Vizianagaram, Andhra Pradesh, India. The nutrient (Phosphorous and Nitrogen content) and organic matter removal efficiency of four natural treatment systems (NTS) having different operation, maintenance and loading rates were investigated. The study showed that natural treatment systems have good potential for peri-urban wastewater treatment. It was also observed that waste-stabilization based systems perform better than those based on duckweed and hyacinth plants. Regularly maintained and operated systems show removal efficiency on the order of 80% for organic and nutrients and performed better than others. The study indicates that decentralized, adequately maintained Waste Stabilization Ponds (WSP) offer a viable, self-sustaining and eco-friendly alternative for wastewater treatment to supply irrigation water in rural areas.

PROTOCOL: Video-based interventions for promoting positive social behaviour in children with autism spectrum disorders: a systematic review and meta-analysis.

This is the protocol for a Campbell review. The primary objective for this review is summarising the effectiveness of video-based interventions (VBI) in promoting prosocial behaviours in a population of young people with autism spectrum disorders (ASD). The research questions employed to fulfil this objective include: (1)Do VBI improve prosocial behaviours in children with ASD?(2)Which social skills and interactive behaviours are most successful? (3)Do VBI generally have successful rates of skill generalisation and response maintenance? (4) Do demographic characteristics (age, gender) of participants influence the effectiveness of VBI's?

Spatial and quantitative assessment of the correlation between sinus rhythm and atrial fibrillation voltage mapping to identify low voltage substrate in persistent atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG) through DO637/22-3 Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg through the Research Seed Capital (RiSC) program. Introduction Presence of left atrial (LA) fibrotic low voltage substrate (LVS) is associated with high risk for arrhythmia recurrences in patients undergoing pulmonary vein isolation (PVI) for atrial fibrillation (AF). PVI and additional ablation of LVS - as identified by mapping in sinus rhythm (SR) or AF - has been reported to improve SR maintenance rates, despite differences of the extent and distribution of LA-LVS in SR versus AF. Aims To study the relationship between SR and AF voltage maps, we sought to identify the optimal AF voltage threshold providing the highest concordance in the extent and distribution of LVS when comparing voltage maps in SR vs. AF. Methods Using the statistical shape modelling software Scalismo, the voltage information from the SR and AF maps (acquired prior to PVI) from 28 patients (66 ± 7 years, 46% male, 82% persistent AF) was projected onto a representative LA-geometry. Sensitivity and specificity of LVS identification were calculated for varying thresholds during AF and the correlation between the SR (threshold 0.5mV) and AF maps was assessed and areas of agreeing LVS classification (SR & AF) were identified for each patient. The data of all 28 patients were combined to a spatial histogram of agreement between SR and AF low voltage maps. Results The correlation between SR and AF maps was high across all patients, with agreement at 60-95% of all mapped sites (Figure A: each red triangle represents one patient and the respective agreement of LVS classification and substrate extent). The optimal AF threshold - to identify LA-LVS <0.5 mV in SR - was 0.29 mV (Q1-3: 0.20-0.37 mV) and was independent of the underlying extent of LVS during SR (Figure A: each blue asterisk represents one patient and the corresponding AF threshold and substrate extent). Agreement between LVS in AF vs. SR was high across most (>90) patients on the anterior LA, lateral LA and the left atrial appendage. Lower agreement (60% of patients) was observed in the posterior wall (Figure B). Conclusions SR and AF voltage maps reveal high spatial concordance in low voltage substrate at the anterior LA, lateral LA and LA appendage, however significant discordances in LVS are found in 40% of patients at the posterior LA. Further studies on an extended patient cohort should assess if regional voltage-thresholds would result in an improved substrate concordance between AF and SR substrate maps. Abstract Figure.

Evaluation of Pharmacologic Interventions for Weight Management in a Veteran Population.

Veterans are disproportionately impacted by weight-related morbidity: 40% of veterans are categorized as obese and an additional 38.5% are overweight. Medications are recommended as an adjunct to lifestyle and dietary changes. Guidelines recommend 7 weight management medications, including orlistat, liraglutide, phentermine, phentermine/topiramate, lorcaserin, and naltrexone/bupropion. A single-center, retrospective chart review was conducted for patients who started weight management medications at Veteran Health Indiana in Indianapolis. The primary outcomes included total weight loss and weight loss as a percentage of baseline weight at 3, 6, 12, and > 12 months of therapy. Secondary outcomes included weight loss of 5% from baseline, rate of successful weight maintenance after initial weight loss of 5% from baseline, adverse drug reaction monitoring, and use of weight management medications across clinics at this site. The absolute weight difference over 12 months of weight management medication therapy was 15.8 kg. At each time point, weight loss was found to be statistically significant when compared with baseline (P < .001). Average weight change was greatest with orlistat (-25.9 kg) and naltrexone/bupropion was associated with a gain of 2.1 kg over the duration of the study. A majority of the patients analyzed lost the guideline-recommended 5 to 10% from baseline while taking weight management medication. Weight management medications in a veteran population produced initial weight loss consistent with previous studies. However, there is room for improvement in follow-up strategies to promote greater weight maintenance after initial weight loss. Considering the high health care costs, personal burden, and potential long-term complications associated with obesity, efforts to promote continued development of programs that support weight management and maintenance are imperative.

Predictors of Poor Plasma Glucose Maintenance in Type II Diabetic People with Ophthalmic Complication: The Case of Dessie Hospitals in Ethiopia.

BackgroundDiabetes mellitus, the commonest metabolic disorder, leads to cardiovascular diseases, neurological problems, kidney injury, and visual disturbances. Such complications can be prevented by maintaining plasma glucose level in the normal range, including ophthalmic complications. Hence, this study intended to pinpoint predictors of poor plasma glucose maintenance in type II DM people with ophthalmic complication.MethodsWe conducted a cross-sectional survey using simple random sampling approach to recruit participants. An interviewer-based questionnaire was used and ophthalmic complication was determined by visual acuity test. We used statistical package for social sciences version 23 to analyze the data and descriptive statistics were calculated. Predictors were ascertained using multivariable logistic regression at p≤0.05. Besides, AOR with 95% CI was also estimated to show extent of association.ResultsThe prevalence of poor plasma glucose maintenance was 65.1% (56.6–73.6). Poor plasma maintenance was predicted by the absence of formal education (OR: 0.67; 0.20–2.23), DM history of family members (OR=4.29; 1.33–13.83), longer duration of diabetes (OR: 3.02; 1.09–8.63), insulin use (OR=10.05; 2.72–52.35), and less physical exercise (OR=2.91; 1.47–5.76).ConclusionStudy subjects with no education, DM history of family members, prolonged DM, insulin medication, and inadequate exercise had higher rate of poor plasma glucose maintenance. Health professionals should educate patients on the importance of self-adherence to plasma glucose monitoring, and encourage them to practice recommended physical activity.

Bayesian Regularizers of Artificial Neural Networks applied to the reliability forecast of internal combustion machines in the short-term

Predictive as well as preventive maintenance are tools of maintenance programs that aim to increase or maintain the life expectancy of an equipment through computational techniques and tools. Bearing in mind that the power generation industry has a high maintenance rate with machines and / or electric generators stopped, this research aims to develop a computational model for predicting the Reliability Key Performance Indicator (KPI) to identify how available the equipment will be in a time span of 22 days, for this the methodology to be used will be based on analyzes and tests of artificial neural network (ANN) architectures using the Bayesian Regularizers training algorithm, alternating the transfer functions in the layers hidden to find the best state of convergence and the minimum Root Mean Square Error (RMSE) value calculated between the real and simulated outputs. According to the results obtained by the training, validation and test steps, the algorithm presented a RMSE rate of 0.0000104202 and a 99.9% correlation between the real and simulated values, thus the model is able to identify which machine will have the greatest efficiency and less efficiency within the defined time span.

Examine the Underlying Causes of Flexible Pavement Deteriorations, Methods of Maintenance and Pavement Condition Rating

In India, the deterioration of asphalt pavement is a major issue in the road and highway sectors. It may occur due to a variety of factors such as premature aging, improper mix design, inadequate construction, and material quality, the improper structure design of pavement considering traffic, and a lack of preventive maintenance, among others. There are many types of distress in asphalt pavements known as disintegration (raveling, and potholes), fracture (spalling and cracking), and distortion (slippage deformation of permanent). This research aims to perform a physical survey for distress analysis and pavement condition rating using the IRC method. As a case study, four urban flexible pavement roads in the Pimpri Chinchwad Pune area were chosen. The roads are visually inspected to measure the severity to detect the types and extent of the distresses. Based on the severity of the distresses, the IRC method assigns a grade of 0 to 1.0 for poor condition roads, 1.1 to 2.0 for fair condition roads, and 2.1 to 3.0 for good condition roads. As per the pavement condition rating, two of the four urban roads were found to be in fair condition, while the other two were in poor condition. The cost-effective treatments were recommended from a variety of treatments such as slurry seal, fog seal, crack seal, micro-surfacing, thin cold or hot mix bituminous overlays, and surface dressing

Comparison of isotonic versus hypotonic intravenous fluid for maintenance fluid therapy in neonates more than or equal to 34 weeks of gestational age – a randomized clinical trial

Background and objectives The use of hypotonic fluids as maintenance therapy in the neonatal population has been in practice for a long time, but there is a lack of evidence for the choice of this fluid in neonates. This study compared isotonic (sodium chloride, 0.9%, and dextrose, 5%) versus hypotonic (sodium chloride, 0.15%, and dextrose, 5%) intravenous fluid for maintenance fluid therapy in neonates more than or equal to 34 weeks of gestational age. Methods In this triple-blind randomized clinical trial, we recruited 60 neonates admitted to a neonatal intensive care unit of a tertiary care children's hospital from June 2017 through May 2018 with normal baseline serum sodium levels, anticipated to require intravenous maintenance fluids for 24 hours or longer (intention-to-treat analyses). Patients were randomized to receive isotonic or hypotonic intravenous fluid at maintenance rates for 72 hours. The primary outcome was the incidence of hyponatremia (defined as serum sodium <135mEq/L) at 24 hours in both groups. The secondary outcomes were incidence of hypernatremia at 24 hours (defined as serum sodium >145 mEq/L), the incidence of hypo and hypernatremia at 48 and 72 hours, mean serum sodium at 24, 48, and 72 hours, rate of change of serum sodium during the study period, mean serum osmolality at the end of the study period, the absolute difference in osmolality during the study period, the absolute difference in weight during the study period and edema during the study period. Results Of 60 enrolled neonates, 31 received isotonic fluids and 29 received hypotonic fluids. Three patients in the hypotonic group developed hyponatremia and none in isotonic group at 24 h (RR = 0.13; 95% CI = 0.007 − 2.485; p = .106). Fourteen neonates developed hypernatremia in the isotonic group and one in hypotonic group at 24 h (RR = 13.09; 95% CI = 1.83 − 93.4; p = .0001). Conclusions Our study results do not support the hypothesis that isotonic fluid is superior to hypotonic fluid in reducing the proportion of neonates developing hyponatremia after 24 hours of intravenous fluid therapy. The proportion of neonates developing hypernatremia is significantly higher after using isotonic fluid for maintenance therapy. TRIAL REGISTRATION CTRI/2017/05/008585

Nutritional Intervention Facilitates Food Intake after Epilepsy Surgery.

Background: We investigated whether nutritional intervention affected food intake after epilepsy surgery and if intravenous infusions were required in patients with epilepsy. We hypothesized that postoperative food intake would be increased by nutritional intervention. The purpose of this study was to compare postoperative food intake in the periods before and after nutritional intervention. Methods: Between September 2015 and October 2020, 124 epilepsy surgeries were performed. Of these, 65 patients who underwent subdural electrode placement followed by open cranial epilepsy surgery were studied. Postoperative total food intake, rate of maintenance of food intake, and total intravenous infusion were compared in the periods before and after nutritional intervention. Results: A total of 26 females and 39 males (age range 3–60, mean 27.1, standard deviation (SD) 14.3, median 26 years) were enrolled. Of these, 18 females and 23 males (3–60, mean 28.2, SD 15.1, median 26 years) were in the pre-nutritional intervention period group, and eight females and 16 males (5–51, mean 25.2, SD 12.9, median 26.5 years) were in the post-nutritional intervention period group. The post-nutritional intervention period group showed significantly higher food intake (p = 0.015) and lower total infusion (p = 0.006) than the pre-nutritional intervention period group. Conclusion: The nutritional intervention increased food intake and also reduced the total amount of intravenous infusion. To identify the cut-off day to cease the intervention and to evaluate whether the intervention can reduce the complication rate, a multicenter study with a large number of patients is warranted.

Thermoeconomic Simulation of Cascaded and Integrated Vapor Compression-Absorption Refrigeration Systems

The present work is composed by a comparative thermoeconomic analysisbetween two refrigeration systems: Vapor Compression CascadeRefrigeration System (VCCRS) and Integrated Refrigeration System byAbsorption and Vapor Compression (VCACRS). The thermoeconomicanalysis compares the systems under energy, exergy, economic andenvironmental aspects. The development of mathematical models for each ofthe systems is performed through the EES (Engineering Equation Solver)program. The optimized functions are exergy destruction and total cost rate(sum of cost rates of investment, operation, maintenance and enviromental)by minimizing these functions. The optimization method used is theweighted sum of the objectives, this can be achieved by assigning differentweights for each goal, then a new function that represents the linearrelationship between all the objectives is found. In present case the twoobjective functions are exergy destruction and total cost rate. Inmultiobjective optimization, the process of choosing among optimizedsolutions involves the definition of an equilibrium point, also called theideal point. In order to achieve a real solution of the minimum values ofthe described functions simultaneously one must determine which is thesmallest distance from the ideal point to the curve that defines theoptimized solutions. In the study the economical advantage of VCCRS inrelation to VCACRS was demonstrated. VCACRS has a cost 10.26% lowerthan VCCRS while VCCRS has a better exergetic efficiency, with itsdestruction of exergy 38.46% lower than VCACRS.

Persistence of Operant Responding for Food After Prior Cocaine Exposure in Fischer 344 But Not Lewis Rats.

Chronic cocaine exposure has differential neural effects in Fischer 344 (F344) vs Lewis inbred rats that may explain strain-dependent differences during acquisition vs maintenance of cocaine self-administration. We assessed whether prior cocaine exposure alters operant responding for food across various phases (acquisition, maintenance, extinction, spontaneous recovery, reinitiation) in these strains. Lewis and F344 rats (N = 12) were administered three cocaine (15 mg/kg) or saline injections at hourly intervals for 3 consecutive days. Beginning the next day for 24 days, rats had access to operant chambers in which one lever depression resulted in the delivery of a food pellet. Then, four extinction sessions were conducted in which food was no longer available, but other stimulus conditions remained the same. After a 2-day break, spontaneous recovery was assessed over four sessions. Food delivery was then restored for 3 days to test reinitiation followed by a progressive ratio session. Lewis rats acquired the operant faster than F344 rats. F344 rats showed lower maintenance rates than Lewis rats but higher spontaneous recovery responding. Cocaine exposure caused persistence of responding during extinction in F344 but not Lewis rats. All groups reinitiated responding when food was available again and did not differ in final ratios completed under the progressive ratio schedule. That prior cocaine exposure led to persistence of responding in F344 rats during extinction may reflect heightened contextual conditioning that interferes with the ability to extinguish responding. Results have implications for the genetic contribution to relapse-like behaviors. (Am J Addict 2021;00:00-00).

Effect of Solder Particle Size on the Mechanical and Thermal Reliability of Au/Sn Ag Cu/Cu Solder Joints

This paper investigates the effect of solders with different grain sizes (5–15 μm, 2–15 μm, 2–11 μm) on the mechanical and thermal reliability of flip-chip LED chip Au/Sn Ag Cu/Cu solder joints during reflow soldering. The lead-free solder SAC305 was selected as the solder. The microstructure of the IMC interface and the inferred surface of the solder joint is observed, and the microstructure evolution of the solder joint is analyzed. The void ratio of the solder joints under different grain sizes is tested to characterize the influence of the contact area between the chip and the solder joints on the shear stress. In addition, the solder joints were aged for 1000 h under a relative humidity of 85 °C/85%. The photoelectric thermal performance of the FC-LED filament and the influence of high temperature and high humidity aging on the reliability of the filament were tested and analyzed. The results show that when the size of the solder paste is small and the uniformity is poor within a certain range of solder size, the voids in the flux layer are large and concentrated, and the void ratio is significantly higher, which leads to a decrease in the mechanical reliability of the solder joints. The thermal resistance test results show that the cavity will cause excessive thermal resistance, poor heat dissipation, a significant increase in junction temperature, and a decrease in thermal reliability, which in turn leads to severe light aging and ultimately changes in photoelectric performance. When the grain size is 5–15 μm, the uniformity of the particle size is good. After the filament is aged for 1000 h at high temperature and humidity, the light maintenance rate remains at 65.6%, and the filament performance is stable and reliable. It has certain reference value in the actual production process.

Reaction kinetics of lactic acid fermentation from bitter cassava (Manihot glaziovii) starch by Lactobacillus casei

One of the utilizations of bitter cassava is modified cassava flour (Mocaf) production using the fermentation process by Lactobacillus casei. The Mocaf has potential as the future of food security products. It has a characteristic property similar to wheat flour. Lactic acid was also produced as a by‐product during fermentation. After 40 h of fermentation, the proximate composition content of Mocaf was lactic acid content of 0.000928 g/L, hydrogen cyanide levels of 0.02 ppm, starch content of 59.13%, amylose content of 12.98% and amylopectin content of 46.15%. In the scaling‐up process from a laboratory scale to a pilot and industrial scale, modeling is needed. There are five equation models used to describe the kinetic reactions of lactic acid from bitter cassava starch: Monod, Moser, Powell, Blackman, and Product Inhibitor. Each parameter was being searched by a fitting curve using sigmaplot 12.0. The best result in terms of the highest R2 (0.65913) was obtained in the Powell equation with the value of µmax of 1.668/h, Ks of 123.4 g/L, and maintenance rate (m) of 4.672. The kinetic data obtained can be used to design biochemical reactors for industrial scale Mocaf flour production.

Design and Analysis of Automatic Pipe Feeding and Cutting Machine

The main objective of this paper is to design & analysis of an automatic operated pipe cutting machine. Engineers are developing refined machines and modern techniques are employed for economical manufacturing of products. At the same time, we should care about its quality and accuracy. In the era of automation, machines become an intrinsic part of human being. By the use of automation, machine gives great production rate than manual manufacturing process. In today’s competitive market automation has powerfully entered in the industrial manufacturing process in order to increase the production rate and to reduce the process time without conceding with the accuracy of the product. Automatic pipe cutting machine is designed for industries to fragments metals pipes, rods or cylinders of accurate dimensions with high accuracy in less time. oil is used as a working fluid which is pumped with high pressure through pump to perform the mechanical work with the use of proper mechanism. Operator can easily operate Automatic pipe cutting machine. The running and maintenance rate of this machine is very cost-effective.

The Effect of Subsidies to Mature-Age Employment: a Quasi-Experimental Analysis

This paper evaluates the effect of subsidies to employment maintenance on the probability of mature-age workers staying in the firm. Implementing a quasi-experimental design provided by changes in Spanish labor market regulations, we are able to estimate that the end of subsidies had a small though statistically significant and negative impact on workers’ firm attachment rate. Our results show that a 1 pp. increase in the worker’s cost translates into a 0.11 pp. increase in the cumulative probability of the worker separating from the firm in the next five months. This effect is mainly driven by workers with relatively less seniority in the firm, who present lower dismissal costs; and by workers in low-skill jobs, for which the wage productivity gap seems to negatively evolve with age. In terms of a cost-benefit analysis, we document that the previous higher rate of job maintenance was achieved at a disproportionate cost, and therefore the elimination of the subsidy resulted in in Social Security savings larger than foregone wages.

Promoting limbal stem cells proliferation and maintenance using post-thaw human amniotic membranes fortified by platelet lysate

In this study, we aimed to investigate the proliferation and maintenance rate of cultivated human limbal stem cells (hLSCs)-enriched after treating with post-thaw human amniotic membranes (HAMs) fortified by platelet lysate (PL). To prepare PL, three volunteers were selected and platelet rich plasma (PRP) were isolated from their peripheral blood. Thrombin solution was added afterwards at a 1:5 ratio and the produced PL was used to fortify HAMs after a freeze-thaw cycle. hLSCs obtained from corneo-scleral rings of donated cadaveric corneas and cultured on the post-thaw fortified HAMs as the test group. Cell viability as well as genotypic and phenotypic variations in hLSCs-enriched were compared between the test group and the hLSCs cultivated on post-thaw HAMs without PL (as the control group). Cell Viability assessment demonstrated a significant increase of the hLSCs-enriched viability in the test group on days 1 and 3 and a borderline increase after 1 week in comparison to the control group. Tp63 gene expression decreased remarkably on day 7. NGFR gene expression, however, showed a notable increase on days 1, 3, and 7. There was not a significant difference between the hLSCs-enriched in the test and control groups after 1 week, concerning ΔNp63 protein expression. Our findings strongly indicate that applying PL to fortify HAMs after thawing could potentiate hLSCs-enriched proliferation and differentiation to corneal epithelial precursor cells. In this respect, PL-fortified post-thaw HAMs may potentially improve ocular surface wound healing and re-epithelialization.

Profit Analysis of a Standby Repairable System with Priority to Preventive Maintenance and Rest of Server Between Repairs

The paper aims to bring out the profit analysis of a system with cold standby redundancy of two identical units. In the system, we keep one unit in working and the other is to back up the operation. The system requires preventive maintenance after a specific time. The server has the dual role to carry out repair activities in terms of preventive maintenance and repair of the failed unit. In addition to that, the server is allowed to take rest after each repair. There is no need of rest of the server after preventive maintenance. The provision of priority has been made for the preventive maintenance over repairs. The repairs are done to increase the efficiency and productivity level of the system. The failure rate follows exponential distribution while repair time, rest time of the server and preventive maintenance rate follow arbitrary distributions. The significant reliability characteristics including MTSF, long run availability, server busy time due to repair &amp; preventive maintenance, expected number of repairs, expected number of preventive maintenances per unit time and profit function are obtained using the usual stochastic processes approach. For particular values of the parameters, the revenue per unit up-time and cost functions related to repair activities are considered to carry out the profit analysis of the system model. The results are shown graphically and numerically to highlight the effect of different parameters on some significant reliability characteristics

Clinical Safety and Efficacy of Ablation for Atrial Fibrillation Patients With a History of Stroke.

Objectives: To evaluate the clinical safety and efficacy of radiofrequency catheter ablation for atrial fibrillation patients with a history of stroke.Methods and Results: A total of 116 symptomatic, drug-refractory AF patients with a history of stroke, and 1:2 matched patients without a history of stroke were enrolled. Of these, 28 cases occurred stroke within 3 months (Group 1), 88 cases with stroke history longer than 3 months (Group 2), and 232 cases without stroke (Group 3). PVI was performed in all patients, extended to ablation of linear lesions ablation. The periprocedural stroke rates and other procedure-related in-hospital complications did not differ significantly among the three groups. The maintenance rate of SR after the procedure showed no significant difference (p = 0.333), 52.7, 66.4, and 70.7% in Group 1, 2, and 3, respectively. Furthermore, the comparison between a history of stroke and those without it were also shown no significant difference (p = 0.351).Conclusions: Radiofrequency ablation for AF patients occurred stroke, even within 3 months is safe and effective, without higher periprocedural complication rate and recurrence rate.

Long-Term Outcome of Nipple Projection Maintenance After Reconstruction with Clover Flap Technique.

Nipple reconstruction using local skin flap leaves no morbidity in the healthy nipple. However, one disadvantage of this procedure is that the projection is not often maintained. There are few reports on the rate of long-term maintenance of nipple projection. This study aimed to analyze the 5-year results of clover flap (C-F) nipple reconstruction to determine whether it can be used to maintain nipple projection for long periods and to investigate the factors involved in maintenance of nipple projection. Patients that underwent nipple-areola reconstruction using C-F after undergoing a two-stage implant-based breast reconstruction with skin-sparing mastectomy between January 2012 and December 2019 were included. The projection of the reconstructed nipple was measured annually for 5 years postoperatively, and the nipple projection maintenance rate (%) was calculated. The influence of eight factors, namely smoking, irradiation, scarred skin, flap pedicle relative to the mastectomy scar, location of the mastectomy scar, flap suturing, and flap necrosis, on nipple height were evaluated. Overall, 275 patients were enrolled. The average maintenance rates (%) at 1-5 years after surgery were 47.1, 39.8, 36.4, 34.6, and 33.5. Creating a well-vascularized skin flap, designing the pedicle farther away from the mastectomy scar, choosing a surgical technique involving an oblique scar on the side of the nipple by wrapping the skin flaps, and including an appropriate amount of fat tissue inside the reconstructed nipple are important for nipple projection maintenance. Nipples reconstructed using the C-F technique on the artificial mound achieve excellent long-term result. This journal requires that authors assign a level of evidence to each submission to which evidence-based medicine rankings are applicable. This excludes review articles, book reviews, and manuscripts that concern basic science, animal studies, cadaver studies, and experimental studies. For a full description of these evidence-based medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

3D-Printed Collagen Scaffolds Promote Maintenance of Cryopreserved Patients-Derived Melanoma Explants.

The development of an in vitro three-dimensional (3D) culture system with cryopreserved biospecimens could accelerate experimental research screening anticancer drugs, potentially reducing costs and time bench-to-beside. However, minimal research has explored the application of 3D bioprinting-based in vitro cancer models to cryopreserved biospecimens derived from patients with advanced melanoma. We investigated whether 3D-printed collagen scaffolds enable the propagation and maintenance of patient-derived melanoma explants (PDMEs). 3D-printed collagen scaffolds were fabricated with a 3DX bioprinter. After thawing, fragments from cryopreserved PDMEs (approximately 1–2 mm) were seeded onto the 3D-printed collagen scaffolds, and incubated for 7 to 21 days. The survival rate was determined with MTT and live and dead assays. Western blot analysis and immunohistochemistry staining was used to express the function of cryopreserved PDMEs. The results show that 3D-printed collagen scaffolds could improve the maintenance and survival rate of cryopreserved PDME more than 2D culture. MITF, Mel A, and S100 are well-known melanoma biomarkers. In agreement with these observations, 3D-printed collagen scaffolds retained the expression of melanoma biomarkers in cryopreserved PDME for 21 days. Our findings provide insight into the application of 3D-printed collagen scaffolds for closely mimicking the 3D architecture of melanoma and its microenvironment using cryopreserved biospecimens.