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This paper presents a model for on-line prediction of a drill flank wear using changes in vibration amplitude in the drilling process. Prediction of wear-time and wear-amplitude ratio relationships during the drilling process is enabled by this mathematical model through variations in vibration amplitude signals. An empirical method for an in-process approach for quantifying tool wear, and failure following it, is the outcome of the measurement of variations in the ratio of amplitude between torsional-axial dominant first mode (TP1) and the second mode (TP2) frequency. Performance of a series of cutting tests has been undertaken to study the effect of drill flank wear and other independent cutting parameters on the vibration amplitude signals. The objective is extended to finding the relationship between amplitude signals, drill flank wear and various other independent parameters. Details of the flank wear of drill and the ratio of amplitudes seen at various working conditions were determined and collected through experimental procedures. Verification of the model was done through comparison of the experimental values with the predicted values.

Surface roughness is an essential factor to evaluate the quality of component that decides the wear and fatigue properties and influences the quality of assembly. This research article focuses on real time control of surface finish in drilling using geometric adaptive control strategy. The dynamometer sensor and accelerometer are used to capture the force and vibration signals during drilling. A cubic SVM model is employed to model the surface roughness using the force, vibration and machining parameters. The accuracy of the prediction model is found to be 94 %, and the model is successfully used to control the roughness in drilling. The adaptive scheme uses a Neural Network (NN) controller to adjust the drilling parameters for ensuring the set roughness tolerance. The performance of the controller shows the potentiality of the presented methodology for the practical application in industries.

This paper discusses the development and design of two wheeled-type In-Pipe Inspection Robots (IPIRs), Kuzhali I and Kuzhali II, which were created to address the limitations of traditional human inspection methods and earlier robot designs. Specifically, the robots aim to overcome the motion singularity experienced by IPIRs when navigating through curved pipes. Kuzhali I was developed with wheels mounted at an asymmetric angle, which enables the wheels to maintain contact with the pipe's surface, preventing motion singularity. However, Kuzhali I had limitations due to its prismatic mechanism, and thus Kuzhali II was developed with a telescopic mechanism to allow it to pass through vertical pipes with obstacles. Motion analysis was conducted on both robots to demonstrate how they overcome motion singularity and navigate through straight and curved pipelines. Simulation results showed that the forces acting on the robots' wheels fell within 5 N to 12 N, demonstrating stability while navigating pipeline junctions. Experimental tests were conducted on Kuzhali II, and the results were compared to simulation results, showing an error of less than 5%. The results of the experiments indicate that Kuzhali II is safe to use for pipeline inspection, can navigate through vertical pipelines with ease and can overcome motion singularity in curved pipes. These robots offer a faster, more accurate, and safer alternative to human inspection, which can reduce the risk of pipeline failures and associated environmental and safety hazards. [ABSTRACT FROM AUTHOR]

Intelligent machining requires the online adaptation of the machining parameters to improve tool life and product quality and to reduce machining costs. This article presents a novel hybrid adaptive control (HAC) system for a drilling process. The HAC system is a combination of two adaptive controls: geometric adaptive control (GAC) and adaptive control by optimisation (ACO). It keeps the roughness of the holes within tolerance without compromising tool life. A response surface model (RSM) is used for modelling the drill wear and surface roughness with speed, feed, acceleration and force signals as inputs. The model predicts the wear and roughness with prediction accuracies of 97.1% and 93.6%, respectively. The roughness control is achieved through a Massachusetts Institute of Technology rule and tool wear is minimised by genetic algorithm optimisation. The adaptive algorithms are simulated and validated for the machining conditions given by the adaptive algorithms. The results show an improved tool life of 7% and surface roughness of 11%. [ABSTRACT FROM AUTHOR]

Efficacy of eight insecticides along with five plant extracts were tested during rabi 2017-18 and kharif 2018-19 at Agricultural Research Station, Virinjipuram, Vellore, Tamil Nadu. Four applications of treatments viz., acetamiprid 20 SP @ 30 g ai ha-1, imidacloprid 17.8 SL @ 44.5 g ai ha-1, spiromesifen 240 SC @ 120 g ai ha-1, thiacloprid 240 SC @ 120 g ai ha-1, thiamethoxam 25 WG @ 50 g ai ha-1, diafenthiuron 50 WP @ 250 g ai ha-1, dimethoate 30 EC @ 300 g ai ha-1 and profenophos 50 EC @ 300 g ai ha-1, azadirachtin 10000 ppm @ 3.0 mL L-1, neem seed kernel extract 5%, the leaf extracts of neem, Bougainvillea and sorghum/coconut at 10% along with an untreated check at one month interval on 30 day old plants were given. The results showed that spraying of spiromesifen (3.0 Nos. per 3 leaves) was found to record the lowest population of whitefly throughout the crop period followed by thiacloprid (3.3 Nos. per 3 leaves) and thiamethoxam (3.4 Nos. per 3 leaves). The highest population reduction of 79.2, 77.6 and 76.8% was achieved in plots treated with spiromesifen, thiacloprid and thiamethoxam, respectively, over untreated check. With respect to viral disease, spraying of spiromesifen recorded the least incidence of mosaic (4.4%) followed by thiacloprid (5.2%), thiamethoxam (5.9%) and azadirachtin (6.2%). The plots treated with spiromesifen, thiacloprid and thiamethoxam recorded the highest fruit yield of 28.8, 28.0 and 27.2 t ha-1, respectively, with 36.6, 32.9 and 29.3% increase over untreated check and also the highest cost: benefit ratio [ABSTRACT FROM AUTHOR]

A study on the development of biointensive module was carried out at Agricultural Research Station (ARS), Virinjipuram during 2017-19 against viral and phytoplasma diseases of brinjal. The module thus developed was tested in two locations viz., ARS farm, Virinjipuram and in farmers’ field at K.V. Kuppam block of Vellore district to assess the performance of biointensive Integrated Disease Management (BIDM) module against the mosaic, little leaf disease and whitefly during Kharif 2020. The results revealed that the BIDM was found superior in minimising the mosaic incidence in both locations tested and recorded 5.16 and 6.12 per cent also with lowest little leaf incidence. The lowest whitefly population was also recorded in bio-intensive module adopted plots when compared to farmers’ practice at all stages of crop growth. At 30 days after transplanting (DAT), the whitefly population of 4.45 and 3.77 Nos per plant was recorded at ARS, Virinjipuram and in farmers’ field. With respect to fruit yield, an adoption of bio-intensive module registered a significantly higher yield both at ARS farm (34.02 t/ha) and in farmers’ field (30.36 t/ha) coupled with higher benefit cost ratio of 5.84 and 5.18, respectively. Where as in farmers’ practice the lowest fruit yield of 31.71 t/ha with BC ratio of 5.57 at ARS farm and 25.68 t/ha of fruit yield with CB ratio of 1:4.43 in farmers’ field were recorded. [ABSTRACT FROM AUTHOR]

Four applications of treatments viz., acetamiprid 20 SP @0.3gl-1, imidacloprid 17.8 SL @0.5 ml l-1, spiromesifen 240 SC @1.0 ml l-1, thiacloprid 240 SC @1.0 ml l-1, thiamethoxam 25 WG @0.4 g l-1, diafenthiuron 50 WP @1.0 g l-1, dimethoate 30 EC @2.0 ml l-1 and profenophos 50 EC @2.0 ml l-1, azadirachtin 10000 ppm @3.0 ml l-1, neem seed Kernel extract 5%, the leaf extracts of neem, Bougainvillea and sorghum/coconut at 10% along with an untreated check at one month interval on 30 day old plants were given. The results showed that spraying of spiromesifen 240 SC (3.05 Nos./3 leaves) was found to record the lowest population of whitefly throughout the crop period followed by thiacloprid 240 SC (3.28 Nos./3 leaves and thiamethoxam 25 WG (3.39 Nos./3 leaves). The highest population reduction of 79.16, 77.59 and 76.84% was achieved in plots treated with spiromesifen 240 SC, thiacloprid 240 SC and thiamethoxam 25 WG, respectively over untreated check. With respect to viral disease, spraying of spiromesifen 240 SC @1.0 ml l-1 recorded the least incidence of mosaic (4.39%) followed by thiacloprid 240 SC @1.0 ml l-1 (5.22%), thiamethoxam 25 WG @0.4 g l-1 (5.87%) and azadirachtin 10000 ppm @3 ml l-1 (6.22%). The plots treated with viz., spiromesifen 240 SC, thiacloprid 240 SC and thiamethoxam 25 WG recorded the highest fruit yield of 28.79, 28.01 and 27.24 tonnes ha-1, respectively with 36.63, 32.93 and 29.28% increase over untreated check and also the highest Cost: Benefit ratio. [ABSTRACT FROM AUTHOR]

Cryogenic treatment is a thermal treatment process in which the parts are usually cooled to temperatures below −70 C (< 203 K) to induce metallurgical changes in materials. The treatment has shown a significant performance improvement in most of the ferrous materials and it's alloy, by transforming retained austenite to martensite and precipitating secondary carbides. However, the effect of such low-temperature treatment on highly stable super hard material like tungsten carbide (commonly referred to as "cemented carbide") is uncertain. But researchers have reported precipitation of eta-phase carbides, densification of cobalt binder, refinement of tungsten carbide grains, phase transformation of cobalt, and changes in residual stress in cryogenically treated tungsten carbide (WC-Co) material which resulted in increased hardness and wear resistance. Hence, this paper focuses on summarizing the cryogenic treatment parameters used in different studies, the rate of performance improvement in different applications, and reported mechanical and metallurgical changes, which would serve as a pool of knowledge for future researchers. [ABSTRACT FROM AUTHOR]

Accuracy and safety of tank guns are dependent a great degree on the condition of its gun bore. Many parameters affect accuracy and safety and have strong and complex interdependencies. While it is extremely difficult to monitor all these parameters during battle conditions, it is also essential to enhance the accuracy of the gun by measuring and compensating these parameters. Among all, bore wear and bore centreline are predominant factors. The surface characteristics of the bore also are indicative of potential accidents/deterioration, which should be monitored continuously. Hence, condition monitoring of tank gun bore characteristics in near real-time is an impending need with huge potential for enhancing the combat effectiveness of tank formations. This paper analyses various bore parameters affecting accuracy and safety and proposes a comprehensive condition monitoring method that uses vision camera, thermal camera and mechanical profiler. This integrated approach provides enhanced accuracy in measuring surface characteristics of tank bore that has been partially validated. [ABSTRACT FROM AUTHOR]

Copyright of FME Transactions is the property of University of Belgrade, Faculty of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The high yielding blackgram variety VBN 8 is a cross derivative of VBN 3 x VBG 04-008. Average yield of VBN 8 is 900 kg/ha which is 11.9 and 13.5 percent increased yield over the check varieties VBN 6 (804 kg/ha) and CO 6 (793) respectively. It matures in 65 - 70 days. Under irrigated condition, it performed well by recording 988 kg/ha and the yield increases was 15.29 and 22.28 per cent over the check varieties VBN 6 (857 kg/ha) and CO 6 (808 kg/ha) respectively. Under rainfed condition, this variety recorded 871 kg/ha with 23.20 and 25.87 per cent yield increase over the above checks varieties. The special features of this new variety is determinate plant type with synchronized maturity and highly resistant to Mungbean Yellow Mosaic Virus (MYMV) disease, resistant to leaf crinkle and moderately resistant to powdery mildew diseases. [ABSTRACT FROM AUTHOR]

Nowadays, finishing operation in hardened steel parts which have wide industrial applications is done by hard turning. Cubic boron nitride (CBN) inserts, which are expensive, are used for hard turning. The cheaper coated carbide tool is seen as a substitute for CBN inserts in the hardness range (45-55 HRC). However, tool wear in a coated carbide tool during hard turning is a significant factor that influences the tolerance of machined surface. An online tool wear estimation system is essential for maintaining the surface quality and minimizing the manufacturing cost. In this investigation, the cutting tool wear estimation using artificial neural network (ANN) is proposed. AISI4140 steel hardened to 47 HRC is used as a work piece and a coated carbide tool is the cutting tool. Experimentation is based on full factorial design (FFD) as per design of experiments. The variations in cutting forces and vibrations are measured during the experimentation. Based on the process parameters and measured parameters an ANN-based tool wear estimator is developed. The wear outputs from the ANN model are then tested. It was observed that as the model using ANN provided quite satisfactory results, and that it can be used for online tool wear estimation. [ABSTRACT FROM AUTHOR]

Cemented carbide, a generic name applied to the tungsten carbide-cobalt (WC-Co) metal matrix composite is one of the most commonly used material in cutting tool industries. Generally, thermal treatments are not applied to such super hard tool materials as they are highly stable and don't react to such treatments. In this research, cemented carbide tool with low and medium cobalt content were cryogenically treated and its effect on key metallurgical and mechanical properties were studied. The result shows that cryogenically treated cemented carbide tools have 11.1% and 8.3% better flank and nose wear resistance. Metallurgical evaluations revealed the microstructural changes. [ABSTRACT FROM PUBLISHER]

Tool wear and the surface roughness of the workpiece are vital parameters in machining components that affect cost, quality and productivity. This paper describes an adaptive control strategy for a drilling process to optimise the machine parameters and minimise the tool wear and surface roughness. An adaptive neuro fuzzy inference system (ANFIS) is used for modelling the tool wear and surface roughness. Speed, feed and acceleration signals obtained during drilling are used as inputs to the ANFIS model. Bosed on the mode! output, multi-objective desirability optimisation is applied to obtain the optimal feed and speed. Individual desirability functions of tool wear and surface roughness are combined to form the composite desirability. The fuzzy inference system serves to provide the optimal speed and feed based on the composite desirability. A neural predictive controller is used to control the simulated computer numerical control (CNQ servo drive systems. The ANFIS model of tool wear and surface roughness was found to predict values with an error of 6% for tool wear and 4. l%for surface roughness. The proposed adaptive control output shows a deviation of ±2 mm/min for the feed drive and of ±7 r/min for the speed drive. [ABSTRACT FROM AUTHOR]

This study presents a reliable methodology for normalisation of a vibration signal for distance variation through sensor positioning in drilling using the artificial neural network (ANN) technique. Experiments were conducted and vibration signals were recorded for the purpose of estimating the possibilities of tool wear during the drilling process. The results obtained indicate the effect on tool wear monitoring due to the amplitude variation with the distance between the accelerometer and the hole. A feed-forward backpropagation neural network (FFBPNN) was used for nullifying the variation in amplitude to enable an accurate assessment of tool wear. This model utilised the normalised data achieved through normalisation of the amplitude variation factor of the vibration signal and was validated against the test data. The accuracy of the result was found to be 99.9%. [ABSTRACT FROM AUTHOR]

In industrial applications, particularly in aero, marine and medical industries, titanium has received great attention as a useful material and electrical discharge machining as its machining process. Selection of optimal machining parameters in a multi-objective environment is essential for specific workpiece and tool material combination, which is the concern of industries to improve the overall productivity at less cost. In this article, optimization of critical electrical discharge machining parameters such as pulse current, on time of pulse, off time of pulse and tool geometry depending on the responses such as titanium machining rate, graphite wear rate, surface roughness and deviation between entry and exit while machining titanium grade 5 alloy with graphite tool electrode at negative polarity is presented. Taguchi’s L27 orthogonal array was used to design the experiment with interaction between factors. The weighing method was used to integrate different objectives into one performance. The optimal combination of process parameters was found statistically using signal-to-noise ratios. Significance was checked by analysis of variance. Optimum parameters were found to be pulse current 15 A, on time of pulse 50 µs, off time of pulse 200 µs and cylindrical tool geometry. Resultant percentage improvements in different responses were presented. [ABSTRACT FROM PUBLISHER]

The relationship between spine SBRT outcomes and the extent of malignant epidural disease (MED) compression of the cauda equina has yet to be reported. Our objective was to determine clinical, anatomic and dosimetric predictive factors for local failure (LF) and overall survival (OS) in a cohort of patients with spine metastases and epidural disease at the level of the cauda equina. Consecutive patients with cauda equina MED treated with SBRT, between January 1, 2008 and July 1, 2023, were identified and retrospectively reviewed from a prospectively maintained institutional database. MED parameters including linear dimensions, surface area, and volume ratios relative to the spinal canal, lumbar stenosis grading systems, clock position and various dosimetric factors were analyzed for their predictive value for LF post-SBRT and OS. Covariates with a P value ≤ 0.20 on univariate analysis were selected for multivariable analysis (MVA), and those statistically significant (P <0.05) were included in the final model. Ninety-five individual spinal segments (79 patients) with cauda equina MED were identified, of which 69 (73%) were intact and 26 (27%) post-op. Forty-one (43.2%) received 24 Gy in 2 fractions (fr), 27 (28.4%) received 30 Gy in 4 fr, 22 (23.2%) received 28 Gy in 2 fr and 5 (5.2%) received 30 Gy in 5 fr. Median follow-up and median time to LF were 16.3 (IQR 6.7-32.0) months and 4.7 (IQR 2.2-12.1) months, respectively. The cumulative incidence of LF at 6, 12, and 24 months was 12.7%, 12.7% and 17.4% respectively. OS at 6, 12, and 24 months was 79.6%, 58.4% and 40.7% respectively. In the intact cohort only (69/95), factors predictive of a higher risk of LF on MVA were chemotherapy naive (HR = 8.197, 95% CI = 2.198-30.303, P = 0.0017), MED greater than one third of the circumference of the spinal canal (HR = 9.632, 95% CI = 1.863-49.806, P = 0.0069), and lower V50Gy Equivalent Dose in 2Gy Fractions (EQD2) to the MED volume (HR = 1.049, 95% CI = 1.018-1.081, P = 0.0014). These factors retained significance on MVA for LF when combined with the post-op (26/95) cohort (P = 0.0047, 0.0272, 0.0024, respectively). In the intact cohort only, MVA identified oligometastatic disease (HR = 0.381, 95% CI = 0.190-0.764, P = 0.0065) and MED limited to a single spinal level (HR = 0.405, 95% CI = 0.182-0.902, P = 0.0269) as prognostic for OS. Oligometastatic disease and MED limited to a single spinal level also retained significance as predictors for OS on MVA when combined with the post-op (26/95) cohort (P <0.0001, 0.0182, respectively). We identified chemotherapy naive, MED encompassing more than one third of the circumference of the spinal canal, and lower V50Gy EQD2 to the epidural disease volume, as novel predictive factors for higher LF post-SBRT for MED at the cauda equina. Consideration for more aggressive management with decompressive surgery in those with MED spanning greater than a third of the spinal canal circumference and dose escalation to the thecal sac organ-at-risk may improve outcomes. [ABSTRACT FROM AUTHOR]

The most common complication following spine stereotactic body radiotherapy (SBRT) is vertebral compression fracture (VCF). The purpose of this analyses was to determine if predictors of VCF vary according to presence or absence of a pre-existing (baseline) VCF. A retrospective review of a prospectively maintained institutional database of patients treated with SBRT for spinal metastases performed. The primary outcome was VCF. Clinical, dosimetric and radiographic factors were reported with descriptive statistics. The cumulative incidence of VCF was estimated using a competing risk analysis method. The impact of covariates was estimated with Cox proportional hazards model and hazard ratios (HR) generated. From 2008 – 2022, 744 patients with 1813 spinal segments were treated with spine SBRT. The median age was 64.9 years, and 19.1% had a baseline VCF. The majority of segments were treated with 24Gy (42.8%) or 28Gy (27.4%) in 2 fractions, the median dose-per fraction was 12Gy (range = 5-24), 68% were de novo (no prior radiation exposure) and 235 (13.0%) had prior surgical stabilization. 254 VCF event were observed (14%), 179 were iatrogenic and 75 associated with concurrent tumor progression. The 1-, 2- and 5-year VCF rates were 8.3%, 12%, and 15.2%, respectively. 85/254 (33.5%) occurred in those with a baseline VCF and 169/254 (66.5%) in those without. On multivariable analysis (MVA), tumor progression (HR = 2.24, 95% CI = 1.66-3.04, P <0.01), baseline VCF (HR = 1.91, 95% CI = 1.35-2.71, P <0.01), mechanical pain (HR = 2.01, 1.31-3.08, P <0.01), increasing age (HR = 1.015, 95% CI = 1.002-1.03, P <0.02), fewer consecutive segments treated (HR = 0.80, 95% CI = 0.65-0.98, P <0.03), increasing dose to 90% (D90) of the clinical target volume (CTV) as equivalent dose in 2-Gy fractions (EQD2) (CTV D90 EQD2, HR = 1.007, 95% CI = 1.002-1.01, P <0.02) predicted for VCF. Predictors common to segments treated with or without a baseline VCF included concurrent tumor progression and an increasing CTVD90 EQD2. No prior stabilization surgery, involvement of the posterior elements, fewer consecutive segments treated were unique to the baseline VCF cohort, while histology, mechanical pain and higher dose per fraction were unique predictors in the no prior VCF cohort. We report predictive factors for VCF following spine SBRT and observe distinct risk factors according to presence or absence of a baseline VCF that can guide treatment decisions. [ABSTRACT FROM AUTHOR]

Diffusion-weighted imaging (DWI) enables in vivo diffusivity measurement through the ADC. Aggressive hypercellular tumors exhibit restricted water diffusion and low-ADC values. We hypothesized that areas of glioblastoma that have a high likelihood of recurrence would exhibit smaller ADC change during concurrent CRT than those areas responsive to treatment. Our study aims to compare ADC changes within the areas of the gross tumor volume (GTV) that developed recurrence versus those that remained recurrence-free. We reviewed a prospectively collected cohort of patients with glioblastoma imaged between Dec 2017 and Apr 2021 with DWI at planning (Fx0), fraction 10 (Fx10), fraction 20 (Fx20), and 1 month after a standard 6-week course of concurrent CRT (P1M). The GTV was contoured at all time points and included the surgical cavity and any residual enhancing tumor. The contrast-enhancing recurrence was contoured at the first magnetic resonance imaging (MR) timepoint showing progression per RANO 2.0 criteria. The intersection of the GTV and the recurrence volume was labelled resistant-GTV (R-GTV), while the GTV that did not intersect with the recurrence was labelled sensitive-GTV (S-GTV). Patients who did not experience failure within the GTV and had a minimum follow-up of 36 months were included in the analysis, and the entire GTV was labelled S-GTV. The interior of the surgical cavity was contoured at each time point and excluded from measurement of ADC values to avoid bias. Absolute ADC values and ADC changes (%) at each time point relative to Fx0 were compared between R-GTV and S-GTV using one-sided Wilcoxon rank-sum tests. Temporal changes were assessed using a linear mixed-effects model (fixed effects: region, time; random effects: subject). A total of 51 patients were included (median age 56y, range 20-69). The median absolute ADC values for R-GTV and S-GTV were 0.91 (IQR = 0.84-1.08) vs 0.94 (IQR = 0.87-1.10) at Fx0 (P = 0.358), 1.02 (IQR = 0.88-1.18) vs 1.17 (IQR = 0.96-1.35) at Fx10 (P = 0.011), 1.09 (IQR = 0.95-1.22) vs 1.16 (IQR = 1.00-1.44) at Fx20 (P = 0.058), and 1.19 (IQR = 1.07-1.33) vs 1.37 (IQR = 1.17-1.52) at P1M (P = 0.008), respectively. The median relative ADC change for R-GTV and S-GTV was 0.9% (IQR = -2.3-20.4) vs 15.3% (IQR = 7.5-28.5) at Fx10 (P = 0.006), 11.2% (IQR = 2.7-27.4) vs 23.1% (IQR = 11.8-27.8) at Fx20 (P = 0.048), and 22.5% (IQR = 10.1-39.0) vs 33.3% (IQR = 21.1-50.2) at P1M (P = 0.034), respectively. The linear mixed-effects model revealed a significant difference in relative ADC changes between R-GTV and S-GTV (P <0.001). Early ADC change during CRT is an imaging biomarker for treatment response and recurrence prediction in glioblastoma. Regions exhibiting smaller ADC changes during CRT indicate potential sites of recurrence, suggesting utility for MR-guided biologically adapted radiation clinical trials. [ABSTRACT FROM AUTHOR]

The most common complication following spine stereotactic body radiotherapy (SBRT) is vertebral compression fracture (VCF). Iatrogenic VCF has been widely reported, but it has not yet been reported in the context of tumor progression. We hypothesized that predictors of VCF vary with cause, whether iatrogenic or in conjunction with local failure. A prospectively maintained institutional database of patients treated with SBRT for spinal metastases was retrospectively reviewed. The primary outcome was VCF, with or without local failure. Clinical, dosimetric and radiographic factors were reported with descriptive statistics. The cumulative incidence of iatrogenic VCF and VCF with tumor progression was estimated using a competing risk analysis method. The impact of covariates was estimated with Cox proportional hazards model and hazard ratios (HR) generated. From 2008 – 2022, 744 patients with 1813 spinal segments were treated with spine SBRT. The median age was 64.9 years and median follow up was 19.9 months. Of the 254 VCF events (14%), 179 (70.5%) were iatrogenic and 75 (29.5%) associated with concurrent tumor progression. Median time to iatrogenic VCF was 10.1 months and 9.0 months in those with tumor progression. The majority of segments that had an iatrogenic VCF or with tumor progression were treated with 24Gy in 2 fractions (41.8% and 41.3%, respectively) and the median dose per fraction was 12Gy in both (range = 5-24). The 1- and 2-year iatrogenic VCF rates were 6.8% and 9.9%, respectively, and 15.6% and 22.0% in those concurrent with tumor progression, respectively. On multivariable analysis (MVA), spinal level and increasing dose to 90% (D90) of the clinical target volume (CTV) as equivalent dose in 2-Gy fractions (EQD2) were the only predictors common to both iatrogenic VCF and those secondary to tumor progression. Risk factors that uniquely increased the risk of iatrogenic VCF were presence of a baseline VCF (HR = 1.85, 95% CI = 1.25-2.74, P = 0.002), increasing consecutive segments treated (HR = 0.76, 95% CI = 0.64-0.90, P <0.01), and older age (HR = 1.02, 95% CI = 1.002-1.03, P = 0.03). Meanwhile, epidural disease (HR = 2.84, 95% CI = 1.68-4.79, P <0.001), mechanical pain (HR = 3.33, 95% CI = 1.53-7.25, P <0.01) and fewer SBRT fractions (HR = 0.65, 95% CI = 0.45-0.93, P <0.02) were predictive of VCF in those concurrent with tumor recurrence. This first report of predictive factors for VCF following spine SBRT, according to an iatrogenic cause or concurrent with tumor progression, may improve clinical decision making in VCF management. [ABSTRACT FROM AUTHOR]

Persistent auditory verbal hallucination is a clinically significant problem in schizophrenia. Recent studies suggest a promising role for add-on transcranial direct current stimulation (tDCS) in treatment. An optimised version of tDCS, namely high-definition tDCS (HD-tDCS), uses smaller electrodes arranged in a 4x1 ring configuration and may offer more focal and predictable neuromodulation than conventional tDCS. This case report illustrates the feasibility and clinical utility of add-on HD-tDCS over the left temporoparietal junction in a 4x1 ring configuration to treat persistent auditory verbal hallucination in schizophrenia. [ABSTRACT FROM AUTHOR]