Residual Fragments Research Articles

Models to predict the surgical outcome of mini-ECIRS (endoscopic combined intrarenal surgery) for renal and/or ureteral stones

To establish a safer and more efficient treatment strategy with mini-endoscopic combined intrarenal surgery (ECIRS), the present study aimed to develop models to predict the outcomes of mini-ECIRS in patients with renal and/or ureteral stones. We retrospectively analysed consecutive patients with renal and/or ureteral stones who underwent mini-ECIRS at three Japanese tertiary institutions. Final treatment outcome was evaluated by CT imaging at 1 month postoperatively and stone free (SF) was defined as completely no residual stone or residual stone fragments ≤ 2 mm. Three prognostic models (multiple logistic regression, classification tree analysis, and machine learning-based random forest) were developed to predict surgical outcomes using preoperative clinical factors. Clinical data from 1432 ECIRS were pooled from a database registered at three institutions, and 996 single sessions of mini-ECIRS were analysed in this study. The overall SF rate was 62.3%. The multiple logistic regression model consisted of stone burden (P < 0.001), number of involved calyces (P < 0.001), nephrostomy prior to mini-ECIRS (P = 0.091), and ECOG-PS (P = 0.110), wherein the area under the curve (AUC) was 70.7%. The classification tree analysis consisted of the number of involved calyces with an AUC of 61.7%. The random forest model showed that the top predictive variable was the number of calyces involved, with an AUC of 91.9%. Internal validation revealed that the AUCs for the multiple logistic regression model, classification tree analysis and random forest models were 70.4, 69.6 and 85.9%, respectively. The number of involved calyces, and a smaller stone burden implied a SF outcome. The machine learning-based model showed remarkably high accuracy and may be a promising tool for physicians and patients to obtain proper consent, avoid inefficient surgery, and decide preoperatively on the most efficient treatment strategies, including staged mini-ECIRS.

COMPLICATIONS OF MINIMALLY INVASIVE PERCUTANEOUS NEPHROLITHOTOMY IN THE TREATMENT OF KIDNEY STONES AT MILITARY HOSPITAL 103

Objectives: To evaluate the complications of the minimally invasive percutaneous nephrolithotomy (mini-PCNL) in treating kidney stones at Military Hospital 103. Methods: A prospective, longitudinal study on 286 kidney stone patients operated using the mini-PCNL technique at Military Hospital 103 from July 2017 to July 2019. Results: After mini-PCNL, most patients had no complication (77.62%). Bleeding and fever after mini-PCNL were the two most common complications; there were 35 patients with intraoperative bleeding and no need for blood transfusion (12.24%) and 15 patients with fever after surgery and no chills (5.24%). The stone size affected its clearance rate but did not affect fever and bleeding after mini-PCNL. After mini-PCNL, the mean values of Red Blood Cell (RBC), Hemoglobin (HGB), and Hematocrit (HCT) decreased from 4.75 ± 0.53 T/L, 140.38 ± 15.38 g/L, and 0.42 ± 0.04 L/L to 4.25 ± 0.44 T/L, 125.05 ± 13.36 g/L, and 0.38 ± 0.04 L/L, respectively. Conclusion: After mini-PCNL, the complication rate was 22.38%. Bleeding and fever after mini-PCNL were the two most common complications, with 46 patients (16.08%) and 18 patients (6.29%), respectively. The residual stone fragments were 19.58%. The stone size affected its clearance rate but did not affect fever and bleeding after mini-PCNL

Management of Pediatric Urolithiasis in an Italian Tertiary Referral Center: A Retrospective Analysis.

Background and Objectives: In recent years, the prevalence of pediatric urolithiasis has increased in North America and Western countries, though it is endemic in developing countries. The aim of this study is to describe the experience of a tertiary pediatric referral center in the surgical management of pediatric urolithiasis. Materials and Methods: We retrospectively reviewed the experience of patients ≤ 16 years old affected by urinary stones who underwent surgery. Results: From April 2021 to September 2023, 31 pediatric patients underwent surgical procedures for stone diseases at our department: 13 preschool-aged (1-5 years) and 18 school-aged (6-16 years) children. During this period, 12 URSs, 17 RIRSs, and 2 PCNLs were recorded. Five patients had residual fragments at first, so three of them underwent a second endourological lithotripsy (2 RIRSs and 1 URS). Complete clearance was finally achieved in 27 patients. The stone composition was evaluated in 25 cases. Conclusions: Numerous innovations in the surgical treatment of pediatric urolithiasis have resulted from the development of smaller devices and new technology. Our results show how, in experienced centers, retrograde and percutaneous lithotripsy are safe and effective procedures for use in pediatric populations.

Copper-Catalyzed Azide-Alkyne Cycloaddition-Oriented Multifunctional Bio-Orthogonal Linker BPPA: Design, Synthesis and Evaluation.

The multifunctional linker molecules are crucial for the bio-orthogonal reaction for proteomic target profiling. Herein, we wish to present a novel type of biotin-based tetra-functional bio-orthogonal linkers 3a-3h named BPPA which, possessing a unique photolabile phenacyl ester motif, were readily prepared in 85-90% yields by a simple and green one-step protocol from commercially available and inexpensive reagents of biotin acids and 4'-ethynyl/azido 2-bromoacetophenones. The typical click reaction of BPPA linkers 3a and 3e via copper-catalyzed azide-alkyne cycloaddition (CuAAC) took place easily, resulting in the corresponding BPPA-triazole adducts 4a and 4b in nearly quantitative yields. A further cleavability evaluation of 4a and 4b demonstrated that the expected C-O bond detachment could be accomplished efficiently and rapidly by UV irradiation or by ammonia hydrolysis, respectively, resulting in the residual (hydroxyl)acetylphenyl triazole fragment supposed to be attached to proteins during biological manipulations. The BPPA linkers, with dual clickable options of either the terminal azide or alkyne clickable group, exhibit high potentials for various CuAAC-oriented bio-orthogonal reactions.

Experimental replacement of various bladder volumes with allogeneic tissue-engineered constructions

The results of experimental replacement of the bladder wall up to subtotal using multicomponent tissue-engineered structures are presented. Purpose. Development and experimental use of a tissue-engineered structure for replacing various volumes of the bladder wall. Material and methods. The original poly-L,L-lactide matrix is reinforced with silk fibroin. Mesenchymal cells were introduced into the constructs. 6 intact animals underwent filling cystometry. The maximum cystometric capacity was 11.2±0.97 ml. In these same 6 animals, the anesthetic capacity of the bladder was measured, which was 23.83±0.71 ml. 36 animals underwent reconstruction of the bladder using a prepared tissue-engineered construct after resection of the corresponding volume of the organ. Groups of 9 animals received bladder volumes of 5, 10, 15 and 20 ml. The observation period was 3 months. Results: According to computed tomography of the abdominal and pelvic organs (native study and with intravesical administration of a radiocontrast agent), 4, 8, 12 weeks after surgery, a bladder of physiological capacity is determined in all study groups, the implanted structure is visualized as a hyperintense signal in area of the apex of the bladder. no leakage of contrast agent is detected. Filling cystometry in 2 animals that underwent replacement of 20 ml of bladder volume (subtotal replacement) after 12 weeks showed that the capacity of the formed reservoir correlates with preoperative parameters. Macroscopically, the anastomosis zone is consistent in all groups of animals, the tissue-engineered structure is determined at the implantation site, lysis of the structure is noted by 12 weeks of observation with the preservation of small residual fragments at the implantation site. Conclusion. The experimental use of the developed tissue-engineered multicomponent structure turned out to be effective for replacing defects of the bladder wall of various volumes up to subtotal reconstruction. Further study of technologies for the use of tissue-engineered allogeneic constructs can significantly improve the results of treatment of urological pathologies for which obtaining autologous material is not possible.

Synergistic utilization of industrial waste red mud and rice husk ash for eco-friendly geopolymer preparation: enhancing strength and mitigating hazardous leaching.

The prolonged stacking of substantial volumes of industrial waste red mud (RM) can have significantly hazardous effects on the environment. In order to address this critical problem, this study proposes the synergistic preparation of geopolymers utilizing RM in conjunction with another industrial waste, rice husk ash (RHA). Geopolymers with varying incorporation of RHA were prepared using sodium hydroxide and sodium silicate composite alkaline activator. The mechanical properties, microstructure, and environmental characteristics of geopolymers were investigated. The incorporation of RHA significantly enhanced the strength of RM-based geopolymers, with the highest strength of 25.40MPa achieved at 40% incorporation. According to XRD patterns and FTIR spectra, C-(A)-S-H and N-(A)-S-H were generated during the geopolymerization, thereby enhancing the strength of geopolymers. From SEM micrographs of geopolymers, it was evident that the geopolymer matrix was constituted by the encapsulation of unreacted inert particles of RM and residual fragments of RHA with C-(A)-S-H and N-(A)-S-H. The leaching levels of trace elements and heavy metals in geopolymers are both below the regulatory thresholds, thereby effectively mitigating the presence of hazardous substances in raw materials. These findings proved that the reuse of RM and RHA for the synergistic preparation of environmentally friendly geopolymers is a promising approach to address the issue of substantial RM stacking.

Initial experience with robot-assisted ureteroscopy with Ily® Robot.

The aim of this study is to present the first Italian experience with robotic-assisted retrograde intrarenal surgery (rRIRS) using the Ily® platform. Procedures were performed for renal stones using the Ily® Robot (STERLAB, Vallauris, France), which is a ureteroscope holder with multiple degrees of freedom that can be controlled remotely through a wireless controller. In March 2023, consecutive patients with indications for rRIRS were included in the study. Demographic variables and stone characteristics were collected, and standard perioperative data were assessed. The one-month stone-free rate (SFR, i.e. no residual fragments) was evaluated using ultrasound. All participating surgeons filled out a Surgeons' Satisfaction Questionnaire (SSQ) based on a Likert-type scale. The questionnaire focused on: 1) ease of use; 2) ergonomics during renal cavity exploration; 3) stability during stone fragmentation. Among the patients, one had bilateral stones, while two had stones on the right side. The mean stone size was 13 mm. The average operative time was 70 minutes and the mean docking time was three minutes. No perioperative complications were recorded, and all patients were discharged on the first postoperative day. The one-month SFR was 100%. The SSQ scores were as follows: 1) ease of use: 4/5; 2) ergonomics: 5/5; 3) stability during stone fragmentation: 5/5. Based on the initial experience, the results indicate the feasibility, safety, and effectiveness of rRIRS. The ergonomic efficiency of the system was highly appreciated by the surgeons. While a cost-effectiveness analysis within clinical trials is necessary, rRIRS shows the potential for a more sustainable future for endoscopists and an improved workplace environment.

Ureteral Access Sheath Assisted Percutaneous Antegrade Ureteroscopic Lithotripsy for Impacted Ureteral Calculus

We retrospectively evaluated the safety and effectiveness of ureteral access sheath-assisted percutaneous antegrade ureteroscopic lithotripsy in treating ureteral calculus. Between January 2016 and April 2022, 28 patients with ureteral calculus received ureteral access sheath-assisted percutaneous antegrade ureteroscopic lithotripsy. At postoperative 1 month, a plain computed tomography (CT) and kidney ureter bladder X-ray (KUB) were performed to assess stone fragmentation and hydronephrosis. According to postoperative imaging, stone-free was defined as residual fragments 4 mm or less on KUB and 2 mm or less on CT. The mean stone size was 16.3 mm (3-43 mm). The mean stone volume was 1.91 ml (0.13-6.1 ml). The mean operative time was 140 min (60-222 min). Stone-free rate (SFR) was 89.3% on KUB, and 82.1% on CT. Three patients (10.7%) had postoperative fever greater than 38.5°C. There were no complications of grade III or higher according to the modified Clavien-Dindo classification. In the Ellenbogen classification, improvement was observed in hydronephrosis of Grade II or lower. Improvement was also observed in cases with Grade III hydronephrosis. However, due to the presence of residual renal atrophy, there was no change in the classification. The preoperative eGFR was 63 ml/min/1.73 m² (36-101 ml/min/1.73 m²) and the postoperative eGFR was not improved. We conclude that ureteral access sheath-assisted percutaneous antegrade ureteroscopic lithotripsy is effective for treating impacted ureteral calculus.

Exploring optimal settings for safe and effective thulium fibre laser lithotripsy in a kidney model.

To explore the optimal laser settings and treatment strategies for thulium fibre laser (TFL) lithotripsy, namely, those with the highest treatment efficiency, lowest thermal injury risk, and shortest procedure time. An in vitro kidney model was used to assess the efficacy of TFL lithotripsy in the upper calyx. Stone ablation experiments were performed on BegoStone phantoms at different combinations of pulse energy (EP ) and frequency (F) to determine the optimal settings. Temperature changes and thermal injury risks were monitored using embedded thermocouples. Experiments were also performed on calcium oxalate monohydrate (COM) stones to validate the optimal settings. High EP /low F settings demonstrated superior treatment efficiency compared to low EP /high F settings using the same power. Specifically, 0.8 J/12 Hz was the optimal setting, resulting in a twofold increase in treatment efficiency, a 39% reduction in energy expenditure per unit of ablated stone mass, a 35% reduction in residual fragments, and a 36% reduction in total procedure time compared to the 0.2 J/50 Hz setting for COM stones. Thermal injury risk assessment indicated that 10 W power settings with high EP /low F combinations remained below the threshold for tissue injury, while higher power settings (>10 W) consistently exceeded the safety threshold. Our findings suggest that high EP /low F settings, such as 0.8 J/12 Hz, are optimal for TFL lithotripsy in the treatment of COM stones. These settings demonstrated significantly improved treatment efficiency with reduced residual fragments compared to conventional settings while keeping the thermal dose below the injury threshold. This study highlights the importance of using the high EP /low F combination with low power settings, which maximizes treatment efficiency and minimizes potential thermal injury. Further studies are warranted to determine the optimal settings for TFL for treating kidney stones with different compositions.

Analyzing the stress characteristics of glass as a function of cooling rate when applying air and mist for rapid cooling of glass heated to high temperatures

When glass is heated to the softening point of 600–700 ℃ and then cooled rapidly, compressive stress is generated on the glass surface, and residual tensile stress inside. The compressive stress on the glass surface inhibits the growth of cracks on the surface, which strengthens it. In general, rapid cooling of a glass surface is performed by air, and the residual stress on the glass surface varies depending on the process conditions. In this study, a cooling system for glass is proposed by a water mist spraying system applied to glass that has reached its softening point. Initially, to verify the feasibility of the experiment, a numerical analysis of the cooling characteristics is performed. Then, the mist cooling system is designed to conduct cooling experiments by mist and air. The mist is kept constant, and the residual stress and fragment characteristics are analyzed by varying the air speed to determine the possibility of strengthening the glass. It is confirmed that the cooling effect is enhanced when using the mist, even at relatively low air inflow speeds, and that the effect of the mist is weakened when the air velocity exceeds a certain level.

Unsuspected residual coronary guidewire fragment

Unsuspected residual coronary guidewire fragment

Temporal and Spatial Distribution of Residual Film in Soil Profile under Continuous Film Mulching

Plastic pollution in farmland soil has become a significant concern for scientists studying farmland ecosystems. However, the current research focus on the environmental impacts of plastics in soil overlooks crucial factors such as sources, distribution, and persistence. In this study, we examined the distribution of residual film after eight years of film mulching in mid-April 2018. We also assessed changes in spatial distribution from 2018 to 2020. Our findings reveal that eight years of film mulching significantly increased the quantity of agricultural mulch film residues in the soil. The size of residual film fragments varied from 0.25 cm2 to 109 cm2, and the average size, number, and quantity of residues were influenced by soil depth. There was a noticeable downward trend in the quantity of agricultural mulch film residues, decreasing annually by 0.525 kg·ha−1. In contrast, the number of residual films showed an average annual growth rate of 2.13 × 105 p·ha−1. Importantly, we observed a substantial accumulation of residual film fragments below the 10 cm soil layer over time. Fragments ranging from 1–5 cm2 were the most abundant and gradually accumulated in deeper soil layers, enhancing mulching film recovery efficiency. This study provides valuable insights into the influence of mulch cycles on farmland soil profiles, identifying the key locations and size-to-shape ratios of residual films. These findings serve as a theoretical foundation for implementing effective measures to control mulch film pollution in agricultural practices.

Vacuum-assisted Mini-percutaneous Nephrolithotomy for 2–3-cm Renal Stones: A Comparative Study with Retrograde Intra-renal Surgery

PurposeTo compare vacuum-assisted percutaneous nephrolithotomy (VAmini-PCNL) with retrograde intra-renal surgery (RIRS) for the treatment of renal stones measuring 2–3 cm in diameter. Material and methodsThis retrospective study included children receiving treatment for pyelocalyceal stones of 2–3 cm in diameter from November 2018 to September 2022. Consecutive patients undergoing VAmini-PCNL after 2020 were compared with a historically matched group undergoing RIRS. VAmini-PCNL was performed using a 12-Ch nephroscope through a 16-Ch vacuum ClearPetra access sheet. RIRS was performed using a flexible ureteroscope through a ureteral sheath. The endpoints included the need for pre-stenting, duration of surgery, complications, stone-free rate (SFR), and need for secondary procedures. ResultsThe patients were grouped into two with 15 patients for each group. VAmini-PCNL group was not different from the RIRS one for age at surgery [median (range) 6.6 (1–12)years vs. 7.7 (1.5–14)years], and stone diameter [median (range) 2.4 (2.0–2.9)cm vs. 2.3 (2.1–2.8)cm] and density [median (range) 577.5 (421–1068) vs. 541.5 (462–927) Hunsfield Units]. Pre-stenting was necessary in five RIRS patients (33 %). The median duration of surgery was 85.3 (76–112)min for VAmini-PCNL vs. 150.6 (132–167)min for RIRS, p = 0.00001. No major complications were observed. The SFR was 100 % after VAmini-PCNL and 60 % after RIRS, p = 0.02. All residual fragments were removed with a second RIRS. ConclusionVAmini-PCNL was feasible and safe in children aged >1 year. It allowed for a significantly higher SFR despite a significantly shorter operative time than RIRS, which also requires pre-stenting in one-third of patients and a second RIRS in 40 % of cases. Level of EvidenceIII.

The Glycine N-Methyltransferase Case Study: Another Challenge for QM-Cluster Models?

The methyl transfer reaction between SAM and glycine catalyzed by glycine N-methyltransferase (GNMT) was examined using QM-cluster models generated by Residue Interaction Network ResidUe Selector (RINRUS). RINRUS is a Python-based tool that can build QM-cluster models with rules-based processing of the active site residue interaction network. This way of enzyme model-building allows quantitative analysis of residue and fragment contributions to kinetic and thermodynamic properties of the enzyme. Many residue fragments are important for the GNMT catalytic reaction, such as Gly137, Asn138, and Arg175, which interact with the glycine substrate, and Trp30, Asp85, and Tyr242, which interact with the SAM cofactor. Our study shows that active site fragments that interact with the glycine substrate and the SAM cofactor must both be included in the QM-cluster models. Even though the proposed mechanism is a simple one-step reaction, GNMT may be a rather challenging case study for QM-cluster models because convergence in energetics requires models with >350 atoms. "Maximal" QM-cluster models built with either qualitative contact count ranking or quantitative interaction energies from functional group symmetry adapted perturbation theory provide acceptable results. Hence, important residue fragments that contribute to the energetics of the methyl-transfer reaction in GNMT are correctly identified in the RIN. Observations from this work suggest new directions to better establish an effective approach for constructing atomic-level enzyme models.

Phylogenetic analysis of the partial sequences of the env and tax BLV genes reveals the presence of genotypes 1 and 3 in dairy herds of Antioquia, Colombia

Bovine leukemia virus (BLV) is a retrovirus that primarily infects dairy cows. Although few studies have also used the tax gene, phylogenetic studies of BLV use mostly the env gene. The aim of this work was to establish the circulating genotypes of BLV in specialized dairy cattle from Antioquia, Colombia. Twenty blood samples from Holstein Friesian cows were collected, and their DNA was isolated. A PCR was performed for a partial region of the env and tax genes. A phylogenetic analysis was carried out using the maximum likelihood and Bayesian methods for both genes. Nineteen sequences were identified as genotype 1 by env and tax genes. Only one sequence was clustered with genotype 3 and had the highest proportion of different nucleotide sites compared to other strains. Four amino acid substitutions in the 134 amino acid residue fragment of the Env protein were identified in the Colombian sequences, and three new amino acid substitutions were reported in the 296 amino acid residue fragment of the Tax protein. R43K (Z finger), A185T (Activation domain), and L105F changes were identified in the genotype 3 sample. This genotype has been reported in the United States, Japan, Korea, and Mexico, but so far, not in Colombia. The country has a high rate of imported live animals, semen, and embryos, especially from the United States. Although it is necessary to evaluate samples from other regions of the country, the current results indicate the presence of two BLV genotypes in specialized dairy herds.

Comparison of endoscopic versus CT assessment of stone-free status after percutaneous nephrolithotomy (PCNL)

This study is aimed to determine whether postoperative low dose computed tomography (LDCT) imaging is necessary after percutaneous nephrolithotomy (PCNL), or the surgeon's intraoperative assessment of residual fragments (RF) is sufficient and avoidance of postoperative imaging with reduction of radiation exposure can be achieved. Data of all 610 patients who underwent PCNL in prone position in our institution from February 2009 to September 2020 was collected. Parameters such as age, gender, BMI, ASA-Classification, stone related parameters and the surgeon’s assessment of stone-free status were analyzed. The LDCT performed postoperatively was compared to the intraoperative assessment of the surgeon regarding RF. The mean age of patients was 52.82 years; the mean BMI was 28.18 kg/m2. In 418 cases, the surgeon made a clear statement about the presence of RF and postoperative LDCT was carried out. The discrepancy between the two methods (surgeon´s assessment vs. LDCT) was significant at p < 0.0001. The sensitivity, specificity, positive and negative predictive value of the surgeon when assessing RF were 24.05%, 99.45%, 98.28% and 50%. Stone free rate (SFR) after primary PCNL was 45.57%. The overall SFR at discharge was 96.23%. Although the surgeon´s assessment of RF was reliable, postoperative LDCT imaging should still be performed if endoscopic stone clearance is suspected due to the high false negative rate and the low negative predictive value. The optimal timing of postoperative imaging following PCNL remains unclear.

Supine mini percutaneous nephrolithotomy in horseshoe kidney.

The percutaneous nephrolithotomy (PCNL) in Horseshoe kidneys (HSK) is usually performed in the prone position, allowing entry through the upper pole and providing good access to the collecting system. However, in patients with normal kidney anatomy, the supine position is reliable and safe in most cases, but it is unknown whether the supine position is adequate in patients with HSK. The purpose of this study was to describe the results of PCNL in HSK in three different surgical institutions and to evaluate the impact of supine position during surgery, comparing pre-operative and post-operative data, complications, and stone status after surgery. Between 2017 and 2022, a total of 10 patients underwent percutaneous renal surgery for stone disease in HSK. All patients were evaluated pre- and post- operatively with non-contrast CT. we evaluated patients (age and gender), stones characteristics (size, number, side, site and density ), and outcomes. The change in haemoglobin, hematocrit, creatinine and eGFr were assessed between the most recent preoperative period and the first postoperative day. Procedure success was defined as stone-free or presence of ≤4 mm fragments (Clinically Insignificant residual Fragments - CIrF). Complications were registered and classified according to Clavien-dindo Grading System, during the 30 - day postoperative period and Clavien scores ≥ 3 were considered as major complications. Statistical analysis was performed using "r 4.2.1" software, with a 5% significance level. we also compared pre-operative and post-operative data using "wilcoxon signedrank test". No statistical difference was observed between preoperative and post-operative renal function data. At one post operative day CT scan, an overall success rate of 100% was registered. 9/10 patients were completely free from urolithiasis (stone-free rate: 90%), while 1/10 patients had ≤4 mm residual stone fragments (CIrF rate: 10%). No cases of intraoperative complications were registered. Post-operative complications were reported in 1/10 patients. A patient developed urosepsis (defined as SIrS with clinical signs of bacterial infections involving urogenital organs - Clavien-dindo Grade II) after procedure, and was treated with intravenous antibiotic therapy successfully. Conclusions: This study shows that in patients with HSK mini- PCNL in supine position allows to achieve good stone free rate with a very low morbidity. According to our series, the described technique for PCNL in HSK should be an option. Nevertheless these results must be confirmed by further studies.

Reaction mechanism investigation of low Df epoxy-active ester film composites for 10 GHz high-frequency communications

The role of electronic-grade thin film composite materials in packaging circuits (integrated circuits) and printed circuit boards is critical. Developing epoxy-based thin film composite materials with low dielectric loss (Df) is a significant challenge, especially for that used in high frequency communication (eg. 10 GHz). Active esters, as excellent curing agents, do not form strongly polar hydroxyl groups upon reacting with epoxy resins, which offers significant advantages for low Df thin film composites. In this study, a low Df and high thermal resistance thin film composites was prepared by selecting epoxy resins with biphenyl structures and active esters with dicyclopentadiene groups. The introduction of rigid groups reduces the motility of the molecular chains, and its electron conjugation effect weakens the impact of an external electric field on the molecular dipole moment. The essence of low Df is explained by DFT calculations, in which the quenching effect of active esters on oxygen anions reduces the polarity of the molecular. Meanwhile, ensuring sufficient reaction at a sufficiently high temperature can reduce the number of residual free molecule fragments and ensure the integrity of the cross-link network. This work provides a new direction for the design of the next generation of high-performance low Df composites by deeply explaining the nature of active esters in reducing dielectric loss.

Does age impact outcomes of retrograde intrarenal surgery in the elderly? Results from 366 patients from the FLEXible ureteroscopy outcomes registry (FLEXOR)

BackgroundThere has been a consistent increase in the last decades in prevalence of renal stones in elderly.AimsTo evaluate outcomes of retrograde intrarenal surgery (RIRS) for renal stones in elderly and factors associated with postoperative complications and residual fragments (RFs).MethodsData from 12 centers were retrospectively reviewed. Inclusion criteria: ≥ 75 years, renal stones only, normal renal anatomy. Patients were divided into three groups; Group 1: patients aged 75–79 years; Group 2: age 80–84 years; Group 3: age ≥ 85 years. Multivariable logistic regression analyses were performed to assess factors associated with perioperative complications, sepsis, and RFs.Results366 patients were included. There were 189 patients in Group 1, 113 in Group 2, and 64 in Group 3. There was no difference between groups regarding stone features and total surgical time. Median length of stay was significantly longer in Group 3 (6.0 days, vs 2.0 days in Group 2 vs 2.5 days in Group 1, p = 0.043). There was no significant difference in postoperative complications and RFs between the groups. At multivariable logistic regression analysis, female gender (OR 2.82) and maximum stone diameter (OR 1.14) were associated with higher odds of sepsis, while surgical time (OR 1.12) and the use of a reusable ureteroscope (OR 6.51) with overall complications. Stone size (OR 1.23) was associated with higher odds of RFs.ConclusionRIRS showed safety and efficacy for kidney stones in elderly patients. Surgical time should be kept as short as possible to avoid higher odds of postoperative complications, particularly in females.

Size and depth of residual tumor after neoadjuvant chemoradiotherapy in rectal cancer - implications for the development of new imaging modalities for response assessment.

With the shift towards organ preserving treatment strategies in rectal cancer it has become increasingly important to accurately discriminate between a complete and good clinical response after neoadjuvant chemoradiotherapy (CRT). Standard of care imaging techniques such as CT and MRI are well equipped for initial staging of rectal tumors, but discrimination between a good clinical and complete response remains difficult due to their limited ability to detect small residual vital tumor fragments. To identify new promising imaging techniques that could fill this gap, it is crucial to know the size and invasion depth of residual vital tumor tissue since this determines the requirements with regard to the resolution and imaging depth of potential new optical imaging techniques. We analyzed 198 pathology slides from 30 rectal cancer patients with a Mandard tumor regression grade 2 or 3 after CRT that underwent surgery. For each patient we determined response pattern, size of the largest vital tumor fragment or bulk and the shortest distance from the vital tumor to the luminal surface. The response pattern was shrinkage in 14 patients and fragmentation in 16 patients. For both groups combined, the largest vital tumor fragment per patient was smaller than 1mm for 38% of patients, below 0.2mm for 12% of patients and for one patient as small as 0.06mm. For 29% of patients the vital tumor remnant was present within the first 0.01mm from the luminal surface and for 87% within 0.5mm. Our results explain why it is difficult to differentiate between a good clinical and complete response in rectal cancer patients using endoscopy and MRI, since in many patients submillimeter tumor fragments remain below the luminal surface. To detect residual vital tumor tissue in all patients included in this study a technique with a spatial resolution of 0.06mm and an imaging depth of 8.9mm would have been required. Optical imaging techniques offer the possibility of detecting majority of these cases due to the potential of both high-resolution imaging and enhanced contrast between tissue types. These techniques could thus serve as a complimentary tool to conventional methods for rectal cancer response assessment.