Understanding the Relationship between Surface Quality and Chip Morphology under Sustainable Cutting Environments.

Although chip morphology changes according to the machining method and related cutting parameters, chip formation affects the quality of the machined surface. In this context, it is very important to understand the relationship between chip morphology and surface quality, especially in materials that are difficult to machine. In the presented study, the changes in chip morphology, surface morphology, and surface quality criteria (Ra and Rz) that occurred during the milling of precipitation-hardened steel in different cutting environments were analyzed. Milling experiments were carried out in dry, MQL (minimum quantity lubrication), nano-MQL (graphene), nano-MQL (hBN), Cryo, and Cryo-MQL environments using TiAlN-coated inserts and three different cutting speeds and feed rates. While the highest values in terms of Ra and Rz were measured in dry machining, the minimum values were obtained in a nano-MQL (hBN) cutting environment. Due to the lubrication and low friction provided by the MQL cutting environment, chips were formed in thinner segmented forms. This formation reduced the chip curve radius and thus provided a more stable surface morphology. On the other hand, Cryo-ambient gas could not effectively leak into the cutting zone due to the intermittent cutting process, but it increased the brittleness of the chips with the cooling effect and provided a similar surface morphology. The values of minimum Ra and Rz were obtained as 0.304 mm and 1.825 mm, respectively, at a 60 m/min cutting speed and 0.04 mm/rev feed. Consequently, the use of nano-MQL cutting medium is seriously recommended in terms of surface quality in milling operations of difficult-to-machine materials.

Efficacy of Intravenous Ibuprofen and Paracetamol on Postoperative Pain and Tramadol Consumption After Arthroscopic Shoulder Surgery: A Prospective, Randomized, Double-blind Clinical Trial.

Objective: Efficient pain management following arthroscopic shoulder surgery plays a crucial role in decreasing pain intensity, tramadol consumption, and related side effects. This study primarily aimed to examine the analgesic impact of intravenous (IV) ibuprofen and paracetamol on postoperative pain intensity. In addition, as secondary objectives, the study assesses tramadol consumption, determine the global satisfaction score (GSS), analyze hemodynamic parameters, and investigate tramadol-related side effects. Methods: In this study, we enrolled sixty-four patients who were scheduled to undergo arthroscopic shoulder surgery and met the inclusion criteria of having American Society of Anesthesiologists scores between 1 and 3 and falling within the age range of 18 to 85 years. All participants were managed using IV patient-controlled analgesia. These patients were then randomly assigned in a double-blind manner to two groups: one receiving paracetamol (n=32), and the other receiving ibuprofen (n=32). Demographic information, visual analog scale (VAS) and GSS data, hemodynamics, tramadol consumption, and tramadol-related side effects were recorded. Results: There were no significant differences between the two groups regarding demographics, hemodynamics, GSS scores, and tramadol side effects (respiratory depression, pruritus, urinary retention, and nausea and vomiting). VAS scores of the two groups were similar at postoperative 1st, 6th, and 12th hours. However, group ibuprofen significantly reduced the VAS scores at the postoperative 24th hour (p=0.039). On the other hand, the two groups showed no significant differences in GSS scores. Compared with total tramadol consumption during the postoperative 24-hour period, ibuprofen significantly reduced tramadol consumption (p=0.003). Conclusions: The findings of this study indicate a significant reduction in both pain intensity and tramadol consumption when IV ibuprofen was administered 24 hours following arthroscopic shoulder surgery, in comparison with the use of IV paracetamol.

Evaluation of the Mechanical Properties and Drilling of Glass Bead/Fiber-Reinforced Polyamide 66 (PA66)-Based Hybrid Polymer Composites.

In this study, mechanical testing of glass bead (GB), glass fiber (GF), and hybrid (GB/GF) composites was carried out. Following that, drilling tests were undertaken on glass bead/fiber-reinforced hybrid Polyamide 66 (PA66) polymer composites. The purpose of this study is to determine the mechanical properties of the cutting elements and the effect of cutting parameters (spindle speed and feed rate) and reinforcement ratios on thrust force and surface roughness (Ra). The contribution of the cutting parameters to the investigated outcomes was determined using statistical analysis. Optical microscopy and scanning electron microscopy (SEM) was used to inspect the hole quality and damage mechanisms. The results revealed that the feed rate was the most contributing factor to thrust force (96.94%) and surface roughness (63.59%). Furthermore, in comparison to other hybrid composites, the lowest Ra value was obtained as 0.95 µm in samples containing 30% GB, while the Ra value was 1.04 µm in samples containing 10% GF + 20% GB. Polymer PA reinforced with 30% GF had the highest strength, modulus of elasticity, impact strength, and hardness.

Laparoscopic versus open appendectomy in pregnancy: A single center experience.

BACKGROUND: The aim of this study was to compare the obstetric and surgical outcomes of laparoscopic appendectomy (LA) and open appendectomy (OA) performed for pregnant women at a single center. It was the hypothesis of this study that there would be no significant difference in the results. METHODS: The medical records of 57 consecutive pregnant women who underwent an appendectomy between January 2009 and September 2018 were reviewed retrospectively. The patients were divided into 2 groups: OA and LA. The collected data included age, gestational age, diagnostic modalities used, duration of surgery, length of hospital stay, morbidity, and mortality. RESULTS: Eighteen (31%) patients underwent LA and 39 (69%) patients underwent OA. There were no significant differences in the demographic data. The duration of surgery was significantly less in the laparoscopic group (37 vs 57 minutes; p=0.005). There were no statistically significant differences in the outcomes of deep or superficial surgical site infection, length of hospital stay, pre-term delivery, or loss of the fetus. There was no mortality in either group. CONCLUSION: The results of this study suggest that LA can be a safe option for both the pregnant patient and the child. Further prospective, randomized studies with a larger group of pregnant patients with appendicitis are needed to fully determine the effects of laparoscopy in these circumstances.

Is nighttime laparoscopic general surgery under general anesthesia safe?

BACKGROUND: Fatigue and sleep deprivation can affect rational decision-making and motor skills, which can decrease medical performance and quality of patient care. The aim of the present study was to investigate the association between times of the day when laparoscopic general surgery under general anesthesia was performed and their adverse outcomes. METHODS: All laparoscopic cholecystectomies and appendectomies performed at the emergency surgery department of a tertiary university hospital from 01. 01. 2016 to 12. 31. 2016 were included. Operation times were divided into three groups: 08.01-17.00 (G1: daytime), 17.01-23.00 (G2: early after-hours), and 23.01-08.00 (G3: nighttime). The files of the included patients were evaluated for intraoperative and postoperative surgery and anesthesia-related complications. RESULTS: We used multiple regression analyses of variance with the occurrence of intraoperative complications as a dependent variable and comorbidities, age, gender, body mass index (BMI), ASA score, and operation time group as independent variables. This revealed that nighttime operation (p<0.001; OR, 6.7; CI, 2.6-16.9) and older age (p=0.004; OR, 1.04; CI, 1.01-1.08) were the risk factor for intraoperative complications. The same analysis was performed for determining a risk factor for postoperative complications, and none of the dependent variables were found to be associated with the occurrence of postoperative complications. CONCLUSION: Nighttime surgery and older patient age increased the risk of intraoperative complications without serious morbidity or mortality, but no association was observed between the independent variables and the occurrence of postoperative complications.