Improvement of mechanical performance on zirconium dioxide nanoparticle synthesized magnesium alloy nano composite

With excellent mechanical properties and distinct solidification, the AZ31B series magnesium alloy has great potential for targeting engineering applications and synthesized via die casting process found a drawback on oxidation results porosity and reduced mechanical properties. Here, the magnesium alloy AZ31B series nanocomposite was synthesized with varied weight percentages of zirconium dioxide nanoparticles through a liquid metallurgy route with an applied stir speed of 200 rpm under an argon nature. With the help of a scanning electron microscope, the distribution of particles in the composite surface was found to be homogenous and void-free surface, which output results in less percentage of porosity (<1 %), and the composite contained 6 wt% ZrO2 offers superior yield strength (212 ± 3 MPa), tensile strength (278 ± 2 MPa), and impact strength of 16.4 ± 0.4 J/mm2. In addition, 8 wt% ZrO2 blended composite showed the maximum microhardness value (78.3 ± 1 HV). The best-enhanced result of NC3 (AZ31B/6 wt% ZrO2) is suggested for lightweight to high-strength structural applications.

Improved stone quality of life in patients with an obstructing ureteral stone on alpha-blocker medical expulsive therapy

PURPOSE

Though controversial, alpha blockers are used widely for ureteral stone passage. However, its effects on the patient-reported Quality of life (QOL) is unknown. We compared the QoL of patients on alpha-blocker medical expulsive therapy (MET) to patients not on MET (noMET) utilizing the validated Wisconsin Stone Quality of Life (WISQOL).

METHODS

This prospective study included patients prescribed either MET or noMET after presentation with symptomatic, obstructing ureteral stones. The treatment arm was decided at the point of care by the initial treating physician and included analgesia and antiemetics. Tamsulosin (0.4 mg daily) was prescribed for the MET group. The WISQOL survey was administered at baseline, 7-, 14-, 21- and 28-days following discharge from the ED or until stone expulsion.

RESULTS

197 patients were enrolled, of which 116 (59.2%) completed questionnaires for analysis, 91 in the MET group and 25 in noMET. Average ureteral stone size was 4.7 mm (SD 1.8) and 3.1 mm (SD 1.0) for MET and noMET, respectively. Of completed surveys, 105 (90%) were completed at day 7, 67 (57.6%) at day 14, 53 (45.7%) at day 21, and 40 (34.5%) at day 28. MET was associated with improved QoL scores across all WISQOL domains compared to noMET. Stone size, age, race, sex, comorbidity score and a prior stone history were not associated with reduced QoL.

CONCLUSIONS

The use of MET was associated with improved QOL on all WISQOL metrics compared to noMET patients. Improved stone QOL may be an indication of alpha-blocker therapy in patients with ureteral stone colic.

Performance evaluation and chemical oxygen demand removal of tannery wastewater through the aerobic-anaerobic route

With characterized for complex and maximum substance (suspended solids, broke up oil, a mixture of inorganic and chromium sulfides), tannery wastewater was subjected to a treatment process on removal of chemical oxygen demand (COD) via upstream anaerobic sludge blanket reactor where we found reduced departure efficiencies and that process limits were affected by the assortments in regular stacking rates, closeness of chromium, and sulfides. Hence, a combination of the aerobic-anaerobic hybrid reactor was set up for sequential treatment to determine possible COD reduction. This study investigated the biological degradation of tannery wastewater in a laboratory-scale sequential up-flow aerobic-anaerobic reactor. The aerobic zone at the top was packed with spherical ball-shaped polyhedral polypropylene, and the anaerobic zone at the bottom was packed medium with granular media. The aeration flow rate varied by 2 L/min, 4 L/min, and 6 L/min in the aerobic zone, and the reactor maintained an organic loading rate (OLR) of 5 kg COD/m3/d. Parameters like COD and gas yield assess the performance of the reactor. The maximum COD of 86% is removed in the anaerobic zone with an aeration rate of 6 L/min, and the 1800-mL methane gas yield is measured by the 29th day.

Charge Puddles Driven Complex Crossover of Magnetoresistance in Non-Topological Sulfur Doped Antimony Selenide Nanowires

A race to achieve a crossover from positive to negative magnetoresistance is intense in the field of nanostructured materials to reduce the size of memory devices. Here, the unusual complex magnetoresistance in nonmagnetic sulfur-doped Sb2 Se3  nanowires is demonstrated. Intentionally, sulfur is doped in such a way to nearly achieve the charge neutrality point that is evident from switching of carrier type from p-type to n-type at 13 K as inferred from the low-temperature thermoelectric power measurements. A change from 3D variable range hopping (VRH) to power law transport with α = 0.18  in resistivity measurement signifies a Luttinger liquid transport with weak links through the nanowires. Interestingly, high magnetic field induced negative magnetoresistance (NMR) occurring in hole dominated temperature regimes can only be explained by invoking the concept of charge puddles. Spot energy dispersive spectroscopy (EDS), magnetic force microscopy (MFM) measurements, Tmott  and Regel plot indicate an enhanced disorder in these sulfurized nanowires that are found to be the precursor for the formation of these charge puddles. Tunability of conducting states in these nanowires is investigated in the light of interplay of carrier type, magnetic field, temperature, and intricate intra-inter wire transport that makes this nanowires potential for large scale spintronic devices.

Influence of heat input on the mechanical characteristics, corrosion and microstructure of ASTM A36 steel welded by GTAW technique

The Gas Tungsten Arc Welding process weld for the 4 mm thickness of the ASTM A36 steel plate with varied heat input parameters of 0.608 kJ/mm, 0.900 kJ/mm and 1.466 kJ/mm, respectively. The effect of different heat inputs on microstructure, corrosion, and mechanical characteristics of developed weld joints are examined by three zones: heat-affected zone, welded zone, and base metal zone. The optical microscopic results of weld joints illustrate that fine grain structure leads to enhance welding strength. It is revealed that the increased heat input parameter on the weld joint shows a decreased tensile strength and hardness of the weld joint. The corrosion resistance of the weld joint is evaluated by Potentio-dynamic polarization. It facilitates that the corrosion rate of the weld joint is decreased with increasing heat input, which results indicate the best and worst corrosion micrograph of the polygonal ferrite and ferrite plus polygonal ferrite. However, the weld joint prepared with 0.900 kJ/mm heat input found maximum corrosion resistance.

Optimization and prediction of CBN tool life sustainability during AA1100 CNC turning by response surface methodology

The aluminium alloy (AA1100) was familiar with automotive flexible shaft coupling applications due to its high strength, good machinability, and superior thermal and resistance to corrosion characteristics. Machining tool life drives the prominent role for deciding the product quality (machining) act aims to productivity target with zero interruptions. The novelty of this present investigation is the focus on increasing tool life during the complexity of CNC turning operation for AA1100 alloy by using CBN coated insert tool with varied input parameters of spindle speed (SS), feed rate (f), and depth of cut (DOC). Design of experiment (L16), analysis of variance (ANOVA) statistical system adopted with response surface methodology (RSM) is implemented for experimental analysis. The turning input parameters of SS, f and DOC are considered as factors and its SS (900, 1100, 1300, and 1500 rpm), f (0.1, 0.15, 0.2, and 0.25), and DOC (0.1, 0.2, 0.3, and 0.4 mm) values are treated as levels. The investigational analysis was made with the ANOVA technique and the desirability of high tool life with input turning parameters was optimized by RSM, and sample no 11/16 was predicted as high tool life and performed with extended working hours compared to other samples. The RSM optimized best turning parameter combinations are 0.1 mm DOC, 0.2mm/rev to 0.25mm/rev f, and 1300 rpm-1500 rpm SS, facilitating a higher tool life of more than 20min.

Incremental innovations in operation theaters

Background

The field of ophthalmology has been built upon continuous innovations. COVID-19 pandemic has been an important driving force behind many innovations in ophthalmology and other branches of medicine. Innovations in ophthalmology has been a key to surgical progress. The process of promoting innovation in surgery is imperative in the evolving practice of ophthalmology.

Purpose

In this video we demonstrate some incremental innovations in operation theaters which help in increasing the efficiency and improving the performance of a surgeon. These innovations also provide a more comfortable environment for the patient undergoing the surgery.

Synopsis

A few incremental innovations that are described in our video also help in preventing the spread of COVID infection during surgery. This video also showcases a few wet lab innovations that help train residents in their surgical skills.

Highlights

Use and reuse of simple materials make it cost effective and ecofriendly. These incremental innovations help in the smooth running of operation theaters. Thus, they are small improvements in the existing setup and help in creating a smooth and error free OT flow.

Video Link

https://youtu.be/thFLvC-XykE.

Effect of fiber layer formation on mechanical and wear properties of natural fiber filled epoxy hybrid composites

Natural fiber-reinforced polymer matrix composites are gathering significance in future trend applications such as automotive, aerospace, sport, and other engineering applications due to their superior enhanced mechanical, wear, and thermal properties. Compared to synthetic fiber, natural fiber is low adhesive and flexural strength properties. The research aims to synthesize the epoxy hybrid composites by utilizing the silane (pH = 4) treated Kenaf (KF) and sisal fiber (SF) as layering by uni, bi, and multi-unidirectional via hand layup techniques. Thirteen composite samples have been prepared by three-layer formation adopted with different weight ratios of E/KF/SF such as 100E/0KF/0SF, 70E/30KF/0SF, 70E/0KF/30SF, 70E/20KF/10SF, and 70E/10KF/20SF respectively. The effect of layer formation on the tensile, flexural, and impact strength of composites is studied by ASTM D638, D790, and D256 standards. The unidirectional fiber layer formed (sample 5) 70E/10KF/20SF composite is found maximum tensile and flexural strength of 57.9 ± 1.2 MPa and 78.65 ± 1.8 MPa. This composite is subjected to wear studies by pin-on-disc wear apparatus configured with a hardened grey cast-iron plate under an applied load of 10, 20, 30, and 40 N at different sliding velocities of 0.1, 0.3, 0.5, and 0.7 m/s. The wear rate of the sample progressively increases with increasing load and sliding speed of the composite. The minimum wear rate of 0.012 mg/min (sample 4) is found on 7.6 N frictional force at 0.1 m/s sliding speed. Moreover, sample 4 at a high velocity of 0.7 m/s with a low load (10 N) shows a wear rate of 0.034 mg/min. The wear-worn surface is examined and found adhesive and abrasive wear on a high frictional force of 18.54 N at 0.7 m/s. The enhanced mechanical and wear behavior of sample 5 is recommended for automotive seat frame applications.

Mechanical alloying of Mg0.8-XTi0.2 and study the effect of adding (x = 0.2 wt%) transition metal like Sc, Zr, or Nb on their phase transitions, activation energy, and hydrogen storage properties

Till now Mg-based alloys have attracted much attention due to the high storage capacity of hydrogen. An effort was made to evaluate the apparent activation energy and electrochemical behavior of transition metals such as scandium (Sc), zirconium (Zr), and niobium (Nb) alloyed with Mg-Ti. Mg_0.8Ti_0.2, Mg_0.6Ti_0.2Sc_0.2, Mg_0.6Ti_0.2Zr_0.2, and Mg_0.6Ti_0.2Nb_0.2 alloy powders were synthesized using high-energy ball milling. Ballmilled powders were subjected to structural and morphological characterization using X-ray diffraction and scanning electron microscopy respectively. A strong shift in the inter-planar spacing value of milled powders confirmed supersaturated solid solution of Ti and transition metals in Mg. The inter-planar spacing values before and after milling are found to be 0.24 and 0.21 nm, respectively. Mg_0.8Ti_0.2, Mg_0.6Ti_0.2Sc_0.2, and Mg_0.6Ti_0.2Zr_0.2 alloy powders result in the FCC phase while Mg_0.6Ti_0.2Nb_0.2 powders result in BCC phase, however, the entire powders have an amorphous background. SEM-EDS analysis of the milled powders confirmed the presence of Mg, Ti, Sc, Zr, and Nb elements with a small amount of oxygen. Selected area electron diffraction (SAED) pattern of Mg_0.8Ti_0.2 alloy powders exhibits a nanocrystalline nature owing to their polycrystalline ring pattern. Exothermic peak broadening increases after the substitution of Nb and Zr in Mg_0.8Ti_0.2 alloy powder, which exhibits a lower activation energy (188 kJ mol^-1) than others. In cyclic voltammetry, a drenched cathodic peak is observed for Mg_0.8Ti_0.2 at a potential around -0.83 V. In electrochemical impedance spectroscopy, the charge transfer resistance of Mg_0.6Ti_0.2Sc_0.2 is lower than that of Mg_0.6Ti_0.2Zr_0.2 and Mg_0.6Ti_0.2Nb_0.2 alloy but higher than Mg_0.8Ti_0.2 electrode materials, and charge-discharge studies were done on the developed electrode materials. It shows that Mg_0.8Ti_0.2 electrode material delivers a maximum discharge capacity of 535 mA h g^-1.

Intrarenal Pressure with Vacuum-Assisted Ureteral Access Sheaths Using an In Situ Cadaveric Porcine Model

Introduction: Vacuum-assisted ureteral access sheaths (V-UASs) are a new tool designed to evacuate dust or small fragments during retrograde intrarenal surgery (RIRS). There are reports of increased stone-free rates, decreased infections, and decreased operative time with V-UAS usage. The optimal technique and setting for V-UAS has yet to be described. Herein, we investigate real-time intrarenal pressure (IRP) throughout a range of settings using V-UAS in a porcine RIRS model. Materials and Methods: Ureteroscopy was performed in three female porcine cadaver kidneys through a ClearPetra V-UAS. IRP was recorded through a percutaneous catheter at different inflow pressures, sheath sizes, sheath distance from the ureteropelvic junction, and suction settings. Magnitude of change in delta IRP (dIRP) was compared at various settings. Results: There was no statistical difference in IRP when comparing no suction with vent inactivated. As expected, IRP decreased with larger sheath size and lower irrigation pressures. Average IRP dropped ∼18 mm Hg with suction activation (42.30 mm Hg, vent inactivated; 24.45 mm Hg IRP, suction activated; p < 0.0001). Irrigation pressure and sheath size did not make a difference in the dIRP. dIRP was significantly greater at lower suction settings compared with max suction (25.44 dIRP at 200 mm Hg suction, 10.26 mm Hg dIRP at max suction, p = 0.04). In a subset of observations, IRP paradoxically increased to higher than IRP with no suction at all after >5 seconds of activated suction. Conclusion: Use of V-UAS during RIRS can lower mean IRP; however, this effect could reverse with extended suctioning especially under conditions of high vacuum (>200 mm Hg) owing to outflow tract collapse. Our results suggest urologists should use lower suction settings and short, <5-second bursts to maximize therapeutic benefit, and minimize potential shortcomings of V-UAS during RIRS.

Optimization of NaCl based spray corrosion test process parameters of heat treated hybrid metal matrix composites

ABSTRACT. Aluminium hybrid metal matrix composites (AHMMCs) have widely employed in aerospace, transportation, and automotive applications since for their excellent mechanical qualities and high corrosion resistance. In this research, Al8079 is selected as a matrix material. The titanium diboride (TiB2) is selected as hard reinforcement and molybdenum disulfide (MoS2) is used as soft reinforcement. The Al8079/15 wt.% TiB2/x wt.% MoS2 (x = 0, 2.5, 5 and 7.5) HMMCs are fabricated by using stir casting. The composites are heat treated under T6 condition. The density and micro hardness tests are conducted. The optimization on NaCl based spray corrosion test process parameters is done using grey relational analysis (GRA). The selected input process parameters are Al8079/15 wt.% TiB2/wt.% MoS2 (x = 0, 2.5 and 5), pH value of NaCl solution (x = 6, 9 and 12), hang time (x = 24, 48, and 72 h) and pressure (x = 0.7, 0.9 and 1.1 kg/cm2). The selected response parameters are micro hardness, mass loss and wear loss. The L9 Taguchi design is used for optimization. The wear test is conducted at the constant speed of 0.5 m/s, loading rate of 20 N and the sliding distance of 1000 m. The percentage of improvement of GRG from initial setting to experimental is 10.4%.   KEY WORDS: Reinforcement, Stir casting, Optimization, GRA, NaCl Bull. Chem. Soc. Ethiop. 2022, 36(4), 903-914.                                                         DOI: https://dx.doi.org/10.4314/bcse.v36i4.15

Factors Associated with Ureteral Stent Failure in Patients with Malignant Ureteral Obstruction

Introduction: Management of malignant ureteral obstruction (MUO) with ureteral stents remains a clinical challenge, often involving frequent stent exchanges attributable to stent failure or other urological complications. We report our institutional experience with ureteral stents for management of MUO, including analysis of clinical factors associated with stent failure. Methods: We performed a retrospective review of patients treated with indwelling ureteral stents for MUO in nonurothelial malignancies at our tertiary-care institution between 2008 and 2019. Univariate Cox proportional hazards analysis was performed to identify clinical variables associated with stent failure and stent-related complications. Stent failure was defined as need for unplanned stent exchange, placement of percutaneous nephrostomy (PCN), or tandem stents. Results: In our cohort of 78 patients, the median (range) number of stent exchanges was 2 (0-17) during a total stent dwell time of 4.3 (0.1-40.3) months. Thirty-four patients (43.6%) developed a culture-proven urinary tract infection (UTI) during stent dwell time. Thirty-five patients (44.8%) had stent failure. Twenty-two patients (28.2%) underwent unplanned stent exchanges, 23 (29.5%) required PCN after initial stent placement, and 6 (7.7%) required tandem stents. Ten (28.6%) patients with stent failure were treated with upsized stents, which led to resolution in seven patients. Stent failure occurred with 20/44 (45.4%) Percuflex™, 15/27 (55.6%) polyurethane, and 2/3 (66.7%) metal stents. In patients with ≥2 exchanges (N = 45), median time between exchanges was 4.1 (2.0-14.8) months. Bilateral stenting and history of radiation predicted UTI development. Median overall patient survival after initial stent placement was 19.9 months (95% CI 16.5-37.9 months). Conclusions: Ureteral stent failure poses a significant medical burden to patients with MUO. Better methods to minimize stent-related issues and improve patient quality of life are needed. Using a shared decision-making approach, clinicians and patients should consider PCN or tandem stents early in the management of MUO.

Two-Dimensional Weak Antilocalization Signatures Due to Quantum Coherent Transport in Nanocrystalline SnTe

Nanostructured topological crystalline insulators (TCIs) in the presence of exotic surface states with spin momentum locking reported in individual nanostructures are predicted to hold a great promise for spintronics and quantum computing applications. However, practical application demands a strategy with large-scale production and integration for device applications. In this work, we demonstrate through prominent signatures of weak antilocalization (WAL), arising predominantly from destructive quantum interference on robust surface states, that a correlated TCI phase is possible in the nanobulk assembly of carefully nanostructured quasi-two-dimensional SnTe (edge-to-edge length ∼ 382 nm) synthesized by a simple, rapid, and scalable microwave-assisted solvothermal method. Hikami-Larkin-Nagaoka analysis (T^-0.71), as well as the temperature dependence of resistivity, illustrates an interplay of both conductions from 2D channels and 3D EEI effects as the precursor for the observed WAL at low temperatures (2-6 K). Interestingly, the enhanced thermoelectric power of the sample of ∼45 μV/K, with a p-type carrier concentration of ∼10¹⁸/cm³ at 300 K, makes this SnTe nanocrystalline assembly more attractive as a multifunctional material for large-scale technological applications.

Heart disease diagnosis using optimized features of hybridized ALCSOGA algorithm and LSTM classifier

Cardiac disease is the predominant cause of global death mainly due to its hidden symptoms and late diagnosis. Hence, early detection is important to improve quality of life. Though traditional researches attempted to predict heart disease, most of them lacked with respect to accuracy. To solve this, the present study proposes a hybridized Ant Lion Crow Search Optimization Genetic Algorithm (ALCSOGA) to perform effective feature selection. This hybrid optimization encompasses Ant Lion, Crow Search and Genetic Algorithm. Ant lion algorithm determines the elite position. While, the Crow Search Algorithm utilizes the phenomenon of position and memory of each crow for evaluating the objective function. Both these algorithms are fed into Genetic Algorithm to improve the performance of feature selection process. Then, Stochastic Learning rate optimized Long Short Term Memory (LSTM) is proposed to classify the extracted optimized features. Finally, comparative analysis is performed in terms of accuracy, recall, F1-score, and precision. Moreover, statistical analysis is performed with respect to Sum of Squares (SS), degree of freedom (df), F Critical (F crit), F Statistics (F), p, and Mean Square (MS) value. Analytical results revealed the efficiency of proposed system over conventional methods and thereby confirming its efficiency for predicting heart disease.

Deep Learning Model for Epileptic Seizure Prediction

Prediction of occurrence of a seizure would be of greater help to make necessary precaution for taking care of the patient. A Deep learning model, recurrent neural network (RNN), is designed for predicting the upcoming values in the EEG values. A deep data analysis is made to find the parameter that could best differentiate the normal values and seizure values. Next a recurrent neural network model is built for predicting the values earlier. Four different variants of recurrent neural networks are designed in terms of number of time stamps and the number of LSTM layers and the best model is identified. The best identified RNN model is used for predicting the values. The performance of the model is evaluated in terms of explained variance score and R2 score. The model founds to perform well number of elements in the test dataset is minimal and so this model can predict the seizure values only a few seconds earlier.

Contemporary Pure Laparoscopic Vs Robot-Assisted Laparoscopic Radical Nephrectomy: Is the Transition Worth It?

Introduction: The proportion of robotic procedures continues to rise. The literature reinforces that robotic procedures take longer and are often more costly. We compared cost and perioperative outcomes of laparoscopic radical nephrectomy (LRN) and robot-assisted radical nephrectomy (RARN) at our high-volume center. Materials and Methods: We retrospectively reviewed our 2012-2015 data repository for patients undergoing RARN and LRN for a renal mass. Perioperative and oncologic outcomes were compared. We performed a multivariate analysis of operative time, estimated blood loss, length of stay (LOS), and overall and major 90-day complication rates while controlling for demographic data, Charlson comorbidity index (CCI), tumor size, and surgeon factors. We compared fixed, variable, and distinct procedural costs. Results: We identified 99 LRN and 95 RARN cases. There was no difference in demographic data, tumor size, preoperative renal function, and malignant histology. LRN patients had more comorbidities (49.5% vs 27.3% CCI 2+, p = 0.018). The mean preoperative glomerular filtration rate was higher in the robotic cohort (84.8 vs 75.1, p = 0.48). Mean operative time was 32.7 minutes longer (p = 0.002) and estimated blood loss 145 mL higher (p = 0.007) for the RARN cohort. There was no difference in mean LOS. Major and all 90-day complication rates were no different. The mean procedural cost for RARN was higher by $464 when controlling for operative time (p < 0.001). Fixed costs were not statistically different. Variable costs for RARN were estimated to be $2,310 higher (p = 0.045). Conclusions: Even with cost-conscious, experienced renal surgeons, RARN is associated with a longer procedure, higher supply costs, and higher hospitalization costs. There was no difference in positive surgical margin and complications. There were fewer 30-day readmissions for the RARN cohort, which may represent under-recognized cost savings. With fewer LRN cases in the United States each year, discussion to address cost is warranted. Without better outcomes for robotic surgery, a change in reimbursement to cover costs is unlikely to happen.

Positive Surgical Margins After Robot-Assisted Partial Nephrectomy Predict Long-Term Oncologic Outcomes for Clinically Localized Renal Masses

Introduction: For patients with clinically localized renal masses, positive surgical margins (PSMs) after robotic partial nephrectomy (RPN) have been associated with a higher risk of disease recurrence, although some studies have challenged this conclusion. Owing to inconsistent reports and a lack of long-term robotic data, the clinical impact of PSM after RPN remains uncertain. We evaluate long-term (>6 years) survival outcomes after RPN in patients with clinically localized disease with respect to surgical margin status. Methods: We conducted a retrospective review of patients who underwent RPN for clinically localized renal masses from June 2007 to December 2012 at Washington University School of Medicine. Disease recurrence and overall survival (OS) were stratified on the presence or absence of PSM. The cohort was analyzed to identify patient- and tumor-specific characteristics associated with PSM. Results: We identified 374 RPNs performed from 2007 to 2012 with a mean follow-up time of 77.7 months (SD 32.2 months). PSM was identified in 12 (3.2%) patients. Patients with PSM were at 14-fold increased risk for recurrence with no difference in OS (p < 0.001, p = 0.130, respectively). Patients with PSM had higher incidence of chronic obstructive pulmonary disease (COPD) (25% vs 6.4%) and greater blood loss (425 mL vs 203 mL). Conclusion: With an extended follow-up period of 77 months after RPN, we found that PSM substantially increased the risk of recurrence without impacting OS. Our finding that PSM may occur more frequently in older patients with COPD must be confirmed in larger studies.

Incisional Lumbodorsal Hernias Following Retroperitoneal Robotic Partial Nephrectomies for Small Renal Masses at a High-Volume Tertiary Referral Center

Introduction: Herein we evaluate the incidence of incisional lumbodorsal hernia (ILDH) after retroperitoneal robotic partial nephrectomy (RRPN) and associated patient-specific and tumor-specific risk factors. Furthermore, we aim to evaluate the role of routine lumbodorsal fascial closure for the prevention of ILDH. Methodology: This is a retrospective review of our robotic partial nephrectomy database of all RRPNs performed at Washington University School of Medicine from 2000 to 2020. Postoperative imaging was reviewed for evidence of ILDH. A clinically significant hernia was defined as the protrusion of visceral organ(s) through the lumbodorsal fascia. Patient and tumor characteristics, and fascial closure techniques were analyzed to determine predictors of ILDH. Results: In total, 150 patients underwent RRPN between 2007 and 2020 with an average follow-up of 4.9 (1-37) months. Twelve (8%) ILDHs were identified. Ten (6.7%) patients had herniated retroperitoneal fat whereas 2 (1.3%) patients had herniated colon. All were asymptomatic and managed conservatively. On matched cohort comparison, patients with ILDH had larger tumors than patients without an incisional hernia (3.9 cm vs 2.8 cm, p = 0.029). In general, patient factors were no different between patients with and without ILDH. However, coronary artery disease (CAD) was more prevalent in patients with ILDH (33.3% vs 10.9%, p = 0.028). Patients with ILDH were more likely to have a port site extended for specimen extraction (66.7% vs 38.2%, p = 0.069). Lumbodorsal fascial closure and type of suture material were not associated with prevention of ILDH (p = 0.545, p = 0.637). Conclusion: The radiographic incidence of lumbar incisional hernias after RRPN without routine fascial closure of the extraction incision was 8%. All were asymptomatic and did not require surgical repair. Larger tumor size and CAD were associated with ILDH.

Service design in the healthcare space with a special focus on non-clinical service departments: A synthesis and future directions

Although there has been a tremendous change in the way diseases are diagnosed and treated, the ways in which health care delivery has been managed has seen very little change.Several academic studies have arisen in the area of service design, but an amalgamation of this research, especially in the area of healthcare services is not available. The aim of this systematic review is to evaluate the published research on service design in healthcare and accordingly identify the gaps and scope of future research. After analyzing the articles and reviewing the Service design in healthcare literature, the following are our main contributions: (i) clarification of the service design concept and the developments that appears in the literature review of service design in the healthcare sector; (ii) classification of the service design tools and techniques that are most commonly used in the healthcare sector; (iii) demonstration of the service design as the preponderant construct that is used as a tool and technique to improve quality and efficiency in the healthcare service.The resultant systematic review reveals a change in the type of research carried out, the service design tools used and a shift towards service design from using the co-design tool to other methods. The paper highlights the gaps in the very limited amount of empirical work in the non-clinical healthcare space and accordingly a model is recommended.

Racial Comparison of Patients Undergoing Minimally Invasive Partial Nephrectomy for Renal Masses at a Large Volume Tertiary Center

Introduction and Objective: African American (AA) race has been identified to have a higher incidence of chronic kidney disease (CKD) and worse renal cancer survival compared with Caucasian Americans (CA), irrespective of tumor size, pathologic type, and surgical procedure. We aimed to compare the outcomes between CA and AA patients undergoing minimally invasive partial nephrectomy (PN) at our high-volume center. Materials and Methods: We queried our PN data repository from 2007 to 2017. We identified 981 cases of PN (robotic n = 943 and laparoscopic n = 38), of which there were 852 CA and 129 AA patients. We compared age, sex, body mass index (BMI), operative time, estimated blood loss (EBL), nephrometry score, tumor size, pre- and postoperative estimated glomerular filtration rate (eGFR), length of stay, Charlson Comorbidity Index (CCI), tumor characteristics, and 30-day complication rate. We then estimated the overall survival and disease-specific survival. Results: Age, BMI, operative time, EBL, nephrometry score, tumor size, CCI, length of stay, and sex were not statistically different. The mean preoperative eGFR was higher in the AA cohort (91.4 mL/min/1.73 m² vs 86.1 mL/min/1.73 m², p = 0.007); however, at 1 year, there was no mean difference (76.8 mL/min/1.73 m² vs 74.5 mL/min/1.73 m², p = 0.428). There was a higher percentage of Fuhrman Grade 3/4 in the AA cohort (33.3% vs 22.5%, p = 0.044). The AA cohort had a 2.66 × higher incidence of papillary renal cell carcinoma (RCC) (34.9% vs 13.1%, p < 0.001) and unclassified RCC (3.9% vs 0.4%, p = 0.001). There was no difference in tumor stage (p = 0.260) or incidence of benign histology (15.3% vs 11.6%, p = 0.278). There were no differences in 30-day complications (p = 0.330). The median follow-up was 43.2 months. By using Kaplan-Meier curves, there was no observed difference in overall survival (p = 0.752) or disease-free survival (p = 0.403). Conclusions: Our cohort of AA and CA patients with intermediate follow-up showed no worse outcomes for CKD or survival when undergoing laparoscopic or robotic PN. For low-stage renal cancer, there was no difference in overall survival and disease-free survival at a median follow-up of 43.2 months among AA patients, despite having higher grade tumors and a higher percentage of unclassified RCC. Our cohort of AA patients did have a higher incidence of papillary RCC. The equivalent overall survival and disease-free survival could be due to the earlier discovery of lower stage renal masses incidentally identified on imaging studies performed equally for other reasons in both AA and CA patients.

A63 REFINING THE CANADIAN ASSOCIATION OF GASTROENTEROLOGY GUIDELINE ON SCREENING IN PERSONS WITH A FAMILY HISTORY OF NONHEREDITARY COLORECTAL CANCER OR ADENOMA: A MODIFIED DELPHI PROCESS

Background

In 2018, the Canadian Association of Gastroenterology (CAG) published an extensive systematic review and guideline on screening in persons with a family history (FHx) of nonhereditary colorectal cancer (CRC) and adenoma. While CAG’s recommendations were evidence-based, some recommendations lacked precision (e.g. ranges for some start ages & intervals) and screening cessation age was not addressed, leading to implementation challenges for practitioners and CRC screening programs.

Aims

To review and update the evidence since the 2018 guideline and to formulate implementable recommendations in the Ontario context that are aligned with the CAG guideline.

Methods

ColonCancerCheck (Ontario’s organized CRC screening program) conducted a modified version of the literature search used by CAG (Jan 2017 - Sept 2019). A 19-member expert panel with Canadian and international representatives from endoscopy, primary care, epidemiology, organized CRC screening programs, Ontario’s cancer system and the general public refined the recommendations of the CAG guideline for the purposes of implementation in an organized CRC screening program using a modified Delphi process. This iterative process involved a series of webinars and anonymous survey rounds where the panel reviewed evidence materials and provided online feedback to develop, refine & achieve consensus on screening recommendations in persons with a FHx of CRC/adenoma. Consensus was achieved if ≥75% of members agreed or strongly agreed with the statement.

Results

Six new systematic reviews and 2 new guidelines were identified. New evidence included data on the absolute risk (10 year & lifetime risk) of CRC by type of FHx, as well as the performance of fecal immunochemical testing (FIT) and barriers to CRC screening in persons with a FHx of CRC. The expert panel participated in 3 webinars and 4 online surveys to arrive at consensus. Panel recommendations and level of consensus will be reported for the 6 statements (Table).

Conclusions

Building from the CAG guideline, we derived evidence-based and implementable recommendations for screening persons with a FHx of CRC or adenoma.

Funding Agencies

Ontario Health (Cancer Care Ontario)

Ex Vivo Porcine Model for Robot-Assisted Partial Nephrectomy Simulation at a High-Volume Tertiary Center: Resident Perception and Validation Assessment Using the Global Evaluative Assessment of Robotic Skills Tool

Introduction: With increased demands on surgeon productivity and outcomes, residency robotics training increasingly relies on simulations. The objective of this study is to assess the validity and effectiveness of an ex vivo porcine training model as a useful tool to improve surgical skill and confidence with robot-assisted partial nephrectomy (RAPN) among urology residents. Methods: A 2.5 cm circular area of ex vivo porcine kidneys was marked as the area of the tumor. Tumor excision and renorrhaphy was performed by trainees using a da Vinci Si robot. All residents ranging from postgraduate year (PGY) 2 to 5 participated in four training sessions during the 2017 to 2018 academic year. Each session was videorecorded and scored using the global evaluative assessment of robotic skills (GEARS) by faculty members. Results: Twelve residents completed the program. Initial mean GEARS score was 16.7 and improved by +1.4 with each subsequent session (p = 0.008). Initial mean excision, renorrhaphy, and total times were 8.2, 13.9, and 22.1 minutes, which improved by 1.6, 2.0, and 3.6 minutes, respectively (all p < 0.001). Residents' confidence at performing RAPN and robotic surgery increased after completing the courses (p = 0.012 and p < 0.001, respectively). Overall, residents rated that this program has greatly contributed to their skill (4/5) and confidence (4.1/5) in robotic surgery. Conclusions: An ex vivo porcine simulation model for RAPN and robotic surgery provides measurable improvement in GEARS score and reduction in procedural time, although significant differences for all PGY levels need to be confirmed with larger study participation. Adoption of this simulation in a urology residency curriculum may improve residents' skill and confidence in robotic surgery.

Analysis of Ureteral Diameter and Peristalsis in Response to Irrigant Fluid Temperature Changes in an In Vivo Porcine Model

Objective: It has been previously reported that warming irrigation fluid higher than body temperature may decrease ureteral spasm and thereby facilitate ureteroscopic access to the proximal ureter. Our objective was to examine the effects on ureteral peristalsis and ureteral diameter if the irrigant was warmed to just under the biological threshold for injury. Materials and Methods: Two female adult Yorkshire pigs were studied in this pilot study. In the first pig, a dilute mixture of contrast and irrigation fluid at 37°C and then at 43°C was instilled for 30 minutes into each renal pelvis through a ureteral catheter at 40 mm Hg. Retrograde pyelogram images were captured for each trial and the caliber of the ureter was measured using Vitrea^® software. In the second pig, a lumbotomy was performed, and a magnetic sensor was placed on the extraluminal surface of the ureter to monitor ureteral peristalsis while repeating the aforedescribed regimen. Thirty minutes after the first regimen, the force exerted during placement of a 16F ureteral access sheath (UAS) was recorded at both temperatures using the University of California, Irvine Ureteral Force Sensor. Results: There was no statistically significant difference in ureteral caliber along the length of the ureter at 43°C (p = 0.87, p = 0.32, p = 0.66 for proximal, middle, and distal ureter, respectively). Indeed, there was an increase in peristalsis from baseline with fluid irrigation at 37°C and at 43°C (59% and 65%, respectively). There was no significant difference in the force exerted for UAS placement at either temperature. On histologic analysis, there were no significant changes in ureteral histology or luminal diameter. Conclusions: In a porcine model, warming irrigation fluid to just under the biological threshold for injury did not increase ureteral caliber, decrease ureteral peristalsis, or facilitate UAS placement. As such, during ureteroscopy, we continue to warm our irrigation fluid just to body temperature.

The Risks of Stone Diagnosis and Stone Removal Procedure After Different Bariatric Surgeries

Introduction: Nephrolithiasis is common after malabsorptive bariatric surgery; however, the comparative risk of stone formation after different bariatric surgeries remains unclear. We seek to compare the risk of stone diagnosis and stone procedure after gastric banding (GB), sleeve gastrectomy (SG), short-limb Roux-en-Y (SLRY), long-limb Roux-en-Y (LLRY), and biliopancreatic diversion with duodenal switch (BPDDS). Patients and Methods: Using an administrative database, we retrospectively identified 116,304 patients in the United States, who received bariatric surgery between 2007 and 2014, did not have a known kidney stone diagnosis before surgery, and were enrolled in the database for at least 1 year before and after their bariatric surgery. We used diagnosis and procedural codes to identify comorbidities and events of interest. Our primary analysis was performed with extended Cox proportional hazards models using time to stone diagnosis and time to stone procedure as outcomes. Results: The adjusted hazard ratio of new stone diagnosis from 1 to 36 months, compared to GB, was 4.54 for BPDDS (95% confidence interval [CI] 3.66-5.62), 2.12 for LLRY (95% CI 1.74-2.58), 2.15 for SLRY (95% CI 2.02-2.29), and 1.35 for SG (95% CI 1.25-1.46). Similar results were observed for risk of stone diagnosis from 36 to 60 months, and for risk of stone removal procedure. Male sex was associated with an overall 1.63-fold increased risk of new stone diagnosis (95% CI 1.55-1.72). Conclusions: BPDDS was associated with a greater risk of stone diagnosis and stone procedures than SLRY and LLRY, which were associated with a greater risk than restrictive procedures. Nephrolithiasis is more common after more malabsorptive bariatric surgeries, with a much greater risk observed after BPDDS and for male patients.

Evaluation of Perirenal Anatomic Landmarks on Computed Tomography to Reduce the Risk of Thoracic Complications During Supracostal Percutaneous Nephrolithotomy

Introduction: Supracostal access for percutaneous nephrolithotomy (PNL) has a known increased risk for thoracic complications (TCs). In this study, we perform a radiological review of preoperative and postoperative abdominal CT scans to assess the relationship of the upper pole of the kidney with surrounding landmarks to determine radiographic predictors of TCs. Methods: We performed a retrospective matched cohort comparison of patients who underwent supracostal PNL with and without TCs from 2012 to 2019. An experienced genitourinary (GU) radiologist reviewed pre- and postoperative CT scans to measure the craniocaudal distance between the upper renal pole and the most superior calix to the upper edge of the tip of the 12th rib, the costophrenic angle, and the posterior insertion of the diaphragm. Results: We identified 19 patients who developed TCs after undergoing PNL and compared their CT scans with 24 control patients without TCs. On a preoperative abdominal CT scan, the relationship of the upper edge of the renal parenchyma or upper pole calix with the superior edge of the tip of the 12th rib or costophrenic angle was not found to be predictive of TCs. On receiver operating characteristic analysis, diaphragmatic insertion of ≤2.5 cm below the upper edge of the renal parenchyma on sagittal and transverse views was predictive of TCs (p = 0.046). On postoperative CT scan, the percutaneous nephrostomy tract traversed the posterior insertion of the diaphragm in 80% of patients who had TCs compared with 20% of patients who had no TCs. Conclusions: The decreased distance between the posterior insertion of the diaphragm (medial and lateral arcuate ligaments) and the superior edge of the renal upper pole on preoperative CT scan was associated with TCs from supracostal puncture during PNL. Critical preoperative recognition of this anatomic relationship can help preoperative planning and patient counseling and may prevent or reduce TCs.

Laparoscopic cytoreductive nephrectomy is associated with significantly improved survival compared with open cytoreductive nephrectomy or targeted therapy alone

The aim of the present study was to compare the survival outcomes for patients with metastatic renal cell carcinoma (mRCC) who underwent laparoscopic cytoreductive nephrectomy (CN) vs. open CN vs. targeted therapy (TT) alone at our institution. A retrospective chart review was performed at our institution for patients who underwent CN prior to TT (laparoscopic, n=48; open, n=48) or who were deemed unfit for surgery and received TT alone (n=36), between January 2007 and December 2012. Kaplan-Meier estimated survival and Cox proportional hazards analyses were performed. Laparoscopic CN was associated with significantly longer survival compared with open CN or TT alone (median survival 24 vs. <12 months, respectively; P<0.01). On multivariate analysis, laparoscopic CN was an independent predictor of survival [hazard ratio (HR)=0.48, P<0.01), controlling for preoperative risk factors, while survival was similar between open CN and TT alone (HR=0.85, P=0.54). In our experience, laparoscopic CN appears to be a significant predictor of survival in mRCC. Selection bias of the surgeon for patients with improved survival may account for clinical variables that were otherwise difficult to quantify. For patients who were not candidates for laparoscopic CN, open CN did not confer a survival benefit over TT alone, while it was associated with increased morbidity.

Utility of a Pigtail Cope Loop Catheter for Bladder Drainage in Treating a Large/Persistent Urethrovesical Anastomotic Leak Following Radical Prostatectomy

Background: A large or persistent urethrovesical anastomotic leakage after a laparoscopic or robot-assisted laparoscopic radical prostatectomy (RALRP) although infrequent can be a difficult complication to treat. We describe a simple technique to facilitate resolution of a urethrovesical anastomotic leak by exchanging the in-place bladder Foley catheter for a pigtail drainage catheter. Case Presentation: Between 2014 and 2019, we had three patients who had a large/persistent urine leak after a radical prostatectomy (one laparoscopic and two robot assisted). All three patients had a wide bladder neck requiring bladder neck reconstruction with ureteral orifices close to the anastomosis. The bladder Foley catheter was exchanged to a pigtail Cope loop catheter™ (14F) or an Origin™ self-retaining drainage catheter (16F) under flexible cystoscopic guidance over a guidewire. Placement of a Cope loop bladder catheter stopped anastomotic leakage expeditiously with no need for further intervention. At minimum 3 months follow-up none had bladder neck stricture with 0-1 pad urinary incontinence. Conclusion: Drainage of the bladder through the use of a loop pigtail nephrostomy catheter can be useful in rapidly resolving a large persistent urethrovesical anastomotic leak.

Systemic inflammatory response syndrome in patients with acute obstructive upper tract urinary stone: a risk factor for urgent renal drainage and revisit to the emergency department

Background

In patients seen in the emergency department (ED) with acute stone obstruction many risk factors that indicate need for urgent renal drainage are known. However, in patients discharged from ED without renal drainage factors that can minimize revisit to the emergency department are not fully identified. We evaluated SIRS (systemic inflammatory response syndrome) as a risk factor for urgent renal drainage and revisit to the ED in patients with acute stone colic during their ED visit.

Methods

Retrospective review was performed of patients presenting to a tertiary academic emergency department (ED) from an obstructing ureteral or UPJ stone with hydronephrosis confirmed on an abdominal and pelvic CT scan. Data evaluated over a 3-year period included stone size, presence of UTI, presence or absence of SIRS and other clinical variables as risk factors for urgent renal drainage and ED revisits.

Results

1983 patients with urolithiasis were seen at the ED and 649 patients had obstructive urolithiasis on CT scan. SIRS was diagnosed in 15% (99/649) patients. 54/99 (55%) patients with SIRS underwent urgent renal drainage compared to 99/550 (17%) in non-SIRS patients. In a multivariate analysis SIRS was a predictor of urgent intervention compared to non-SIRS patients (odds ratio 4.6, p < 0.05). SIRS was also associated with increased risk for revisits to the ED (6.9% with SIRS vs. 2.4% with no SIRS, odds ratio 2.9, p = 0.05).

Conclusions

Presence of SIRS in obstructive urolithiasis patients was an independent risk factor of acute urologic intervention and revisits to the ED. A timely consultation with a urologist following discharge from ED for obstructive stone patients with SIRS who had no acute renal drainage may prevent revisit to the ED. Evaluation for SIRS in addition to other clinical risk factors should be considered while making management decision in patients with acute stone obstruction.

Ten-Year Experience with Percutaneous Cryoablation of Renal Tumors: Tumor Size Predicts Disease Progression

Introduction: Percutaneous cryoablation (PCA) has emerged as an alternative to extirpative management of small renal masses (SRMs) in select patients, with a reduced risk of perioperative complications. Although disease recurrence is thought to occur in the early postoperative period, limited data on long-term oncologic outcomes have been published. We reviewed our 10-year experience with PCA for SRMs and assessed predictors of disease progression. Materials and Methods: We reviewed our prospectively maintained database of patients who underwent renal PCA from March 2005 to December 2015 (n = 308). Baseline patient and tumor variables were recorded, and postoperative cross-sectional imaging was examined for evidence of disease recurrence. Disease progression was defined as the presence of local recurrence or new lymphadenopathy/metastasis. Results: Mean patient age was 67.2 ± 11 years, mean tumor size was 2.7 ± 1.3 cm, and mean nephrometry score was 6.8 ± 1.7. At mean follow-up of 38 months, local recurrence and new lymphadenopathy/metastasis occurred in 10.1% (31/308) and 6.2% (19/308) of patients, respectively. Excluding patients with a solitary kidney and/or von Hippel-Lindau, local recurrence and new lymphadenopathy/metastasis occurred in 8.6% (23/268) and 1.9% (5/268) of cases, respectively. Kaplan-Meier estimated disease-free survival was 92.5% at 1 year, 89.3% at 2 years, and 86.7% at 3 years post-PCA. Increasing tumor size was a significant predictor of disease progression (hazard ratio 1.32 per 1-cm increase in size, p = 0.001). Conclusions: PCA is a viable treatment option for patients with SRMs. Increasing tumor size is a significant predictor of disease progression following PCA.

Unplanned 30-Day Encounters After Ureterorenoscopy for Urolithiasis

OBJECTIVE

To identify avoidable predictors of postureteroscopy (URS) unplanned encounters and to minimize 30-day encounters.

MATERIALS AND METHODS

We performed retrospective chart review and telephone surveys on patients who underwent URS for urolithiasis between January and June 2016. Univariate and multivariable analyses evaluated for potential predictors of unplanned encounters.

RESULTS

Of 157 patients, there were 44 (28.0%) unplanned patient-initiated clinical phone calls, 23 (14.6%) emergency department (ED) visits, and 8 (5.1%) readmissions, with pain being the most common complaint during the encounters. Factors associated with a higher rate of phone calls include first-time stone procedure (36.6% vs 20.9%, p = 0.029), outpatient status (30.3% vs 0%, p = 0.021), intraoperative stent placement (31.2% vs 0%, p = 0.006), and stent removal at home (58.8% vs 28.8%, p = 0.014). Factors associated with increased rate of ED visits were first-time stone procedure (22.5% vs 8.1%, p = 0.011) and ureteral access sheath (UAS) usage (29.6% vs 11.8%, p = 0.018). Factors associated with a higher rate of readmissions were lower body mass index (23.9 vs 29.7, p = 0.013), bilateral procedure (20.0% vs 2.9%, p = 0.010), and UAS usage (14.8% vs 3.1%, p = 0.032). Stone burden, operative time, Charlson comorbidity index, and preoperative urinary tract infection were not significantly associated with postoperative encounters.

CONCLUSIONS

Pain, first-time stone treatment, presence of a ureteral stent, outpatient status, bilateral procedures, and UAS usage were common reasons for postoperative encounters after URS. Appropriate perioperative patient education and counseling and adequate pain management may minimize these encounters and improve treatment quality and patient satisfaction.

Development and Validity of a Silicone Renal Tumor Model for Robotic Partial Nephrectomy Training

OBJECTIVE

To provide a training tool to address the technical challenges of robot-assisted laparoscopic partial nephrectomy, we created silicone renal tumor models using 3-dimensional printed molds of a patient's kidney with a mass. In this study, we assessed the face, content, and construct validity of these models.

MATERIALS AND METHODS

Surgeons of different training levels completed 4 simulations on silicone renal tumor models. Participants were surveyed on the usefulness and realism of the model as a training tool. Performance was measured using operation-specific metrics, self-reported operative demands (NASA Task Load Index [NASA TLX]), and blinded expert assessment (Global Evaluative Assessment of Robotic Surgeons [GEARS]).

RESULTS

Twenty-four participants included attending urologists, endourology fellows, urology residents, and medical students. Post-training surveys of expert participants yielded mean results of 79.2 on the realism of the model's overall feel and 90.2 on the model's overall usefulness for training. Renal artery clamp times and GEARS scores were significantly better in surgeons further in training (P ≤.005 and P ≤.025). Renal artery clamp times, preserved renal parenchyma, positive margins, NASA TLX, and GEARS scores were all found to improve across trials (P <.001, P = .025, P = .024, P ≤.020, and P ≤.006, respectively).

CONCLUSION

Face, content, and construct validity were demonstrated in the use of a silicone renal tumor model in a cohort of surgeons of different training levels. Expert participants deemed the model useful and realistic. Surgeons of higher training levels performed better than less experienced surgeons in various study metrics, and improvements within individuals were observed over sequential trials. Future studies should aim to assess model predictive validity, namely, the association between model performance improvements and improvements in live surgery.

Screening for vision-threatening diabetic retinopathy in South India: comparing portable non-mydriatic and standard fundus cameras and clinical exam

PurposeTo evaluate the sensitivity and specificity of a portable non-mydriatic fundus camera to diagnose vision-threatening diabetic retinopathy (VTDR).Patients and methodsA prospective, single-site, comparative instrument validation study was undertaken at the Aravind Eye Care System. Overall, 155 subjects with and without diabetes were recruited. Images from 275 eyes were obtained with the (1) non-mydriatic Smartscope, (2) mydriatic Smartscope, and (3) mydriatic table-top camera of the macular, nasal, and superotemporal fields. A retina specialist performed a dilated fundus examination (DFE), (reference standard). Two masked retina specialists graded the images. Sensitivity and specificity to detect VTDR with the undilated Smartscope was calculated compared to DFE.ResultsGraders 1 and 2 had a sensitivity of 93% (95% confidence interval (CI): 87-97%) and 88% (95% CI: 81-93%) and a specificity of 84% (95% CI: 77-89%) and 90% (95% CI: 84-94%), respectively, in diagnosing VTDR with the undilated Smartscope compared to DFE. Compared with the dilated Topcon images, graders 1 and 2 had sensitivity of 88% (95% CI: 81-93%) and 82% (95% CI: 73-88%) and specificity of 99% (95% CI: 96-100%) and 99% (95% CI: 95-100%).ConclusionsRemote graders had high sensitivity and specificity in diagnosing VTDR with undilated Smartscope images, suggesting utility where portability is a necessity.

Spin reorientation and disordered rare earth magnetism in Ho2FeCoO6

We report the experimental observation of spin reorientation in the double perovskite Ho₂FeCoO₆. The magnetic phase transitions in this compound are characterized and studied through magnetization and specific heat, and the magnetic structures are elucidated through neutron powder diffraction. Two magnetic phase transitions are observed in this compound-one at [Formula: see text] K, from paramagnetic to antiferromagnetic, and the other at [Formula: see text] K, from a phase with mixed magnetic structures to a single phase through a spin reorientation process. The magnetic structure in the temperature range 200-45 K is a mixed phase of the irreducible representations [Formula: see text] and [Formula: see text], both of which are antiferromagnetic. The phase with mixed magnetic structures that exists in Ho₂FeCoO₆ gives rise to a large thermal hysteresis in magnetization that extends from 200 K down to the spin reorientation temperature. At T _N2, the magnetic structure transforms to [Formula: see text]. Though long-range magnetic order is established in the transition metal lattice, it is seen that only short-range magnetic order prevails in the Ho³⁺ lattice. Our results should motivate further detailed studies on single crystals in order to explore the spin reorientation process, spin switching and the possibility of anisotropic magnetic interactions giving rise to electric polarization in Ho₂FeCoO₆.

Determination of role of ceruloplasmin in oral potentially malignant disorders and oral malignancy-A cross-sectional study

OBJECTIVES

In the process of carcinogenesis, lipid peroxidation and increased oxidative stress lead to changes in certain antioxidants. This study was aimed to assess and co-relate serum levels of ceruloplasmin in oral premalignancies and oral cancer so as to gauge its possible association with the process of carcinogenesis and to determine its role as tumor marker.

MATERIAL AND METHODS

The study population comprised of 300 participants, equally divided into six study groups, that is, oral submucous fibrosis (OSMF), oral leukoplakia (OL), nicotina stomatitis (NS), oral malignancy (OM), controls (C), and healthy controls (HC); 5 ml of blood was collected from ante cubital vein from each participant. The serum was analyzed for ceruloplasmin levels using ERBA CHEM 5 PLUS semiautomated chemistry analyzer and diagnostic kit by turbidimetric immunoassay.

RESULTS

There were total 242 males and 58 females, who were between 18 and 82 years of age, with a mean of 45.31 ± 13.97 years. The serum ceruloplasmin levels were significantly increased in OM, OSMF, OL, and NS groups as compared to C and HC groups (p < .001). No statistically significant difference was found in intragroup analysis of the disease groups (p > .05).

CONCLUSION

Serum ceruloplasmin can be used as diagnostic marker for oral premalignant and malignant lesions.