bluuebunny/crossref_metadata_2025 huggingface dataset:
Wheeler-DeWitt canonical quantum gravity in hydrogenoid atoms according to de Broglie-Bohm and the geodesic hypothesis. Einstein’s Quantum Field Equation
Authors: Fullana i Alfonso Màrius Josep , Gómez i Blanch G.
Published: November 2024

We explore the geodesic hypothesis of orbital trajectories of the electrons in hydrogenoid atoms, in the frame of de Broglie-Bohm quantum theory. It is intended that the space-time can be curved, at very short distances, by the effect of the joint action of the energy content of the atomic system and the contribution of the electric and quantum potentials. The geodesic hypothesis would explain the non-lose of energy in the electron orbital trajectories. So we explore a conception where particles and waves interact in a closed system: the waves guide the particles and the particles generate the spacetime perturbation that acts as a wave, beyond the pilot-wave theory.
We establish the equivalence, in a local neighborhood, between the electron trajectory of an hydrogenoid atom in the Minkowskian space where the de Broglie-Bohm can be cast with its movement in a Lorentzian manifold, according to the concept of metric tangent. Through the geodesic condition and the invariance of the elemental length, we establish a relationship between some components of the metrics. But as the particles in microphysics do not follow the Einstein’s field equation, we consider the 3+1 decomposition according to ADM and the quantization in the Wheeler De Witt theory and with a so-called quantum Einstein field equation, with a decomposition of spacetime into three-dimensional sheets of a spatial character. Then we derive from the moment-energy tensor a further equation between the components of the metrics. It opens the avenue to characterize the metric by an exact solution of the Einstein’s field equations.
Diseño de amplificadores CMOS usando gm/ID y su uso como un sistema de primer orden
Authors: Arzate Palma Victor Hugo , Sandoval Ibarra Federico
Published: November 2024

This paper presents the analysis and design of CMOS differential amplifiers using the first-order approach and sizing the transistors with the gm/ID methodology. The design of four amplifiers using parameters of a 130nm CMOS technology is shown, and through spice simulation basic concepts of performance and compliance specifications are verified. The comparison of the performance of the designed amplifiers, in the synthesis of an active low-pass filter, is made to show that the fundamental performance parameters of each amplifier, affects the expected performance of the circuit under design, showing that the CMOS amplifier is not general purpose but that the application takes advantage of the characteristics of the amplifier or, alternatively, the amplifier is designed to meet the requirements of the application. Finally, while each architecture is sized using the same general performance specifications, it is also true that each has a specific and unique overall performance. These differences can be obtained and understood with spice simulation, since the resources of the simulation tool are used properly. All results obtained are at room temperature.
En este trabajo se presenta el análisis y diseño de amplificadores diferenciales CMOS usando la aproximación de primer orden y dimensionando los transistores con la metodología gm/ID. Se muestra el diseño de cuatro amplificadores usando parámetros de una tecnología CMOS 130 nm, y mediante simulación spice se verifican conceptos básicos de desempeño y el cumplimiento de especificaciones. La comparación del desempeño de los amplificadores diseñados, en la síntesis de un filtro activo pasa-bajas, se hace para mostrar que los parámetros fundamentales de desempeño de cada amplificador, afecta el desempeño esperado del circuito bajo diseño, mostrando que el amplificador CMOS no es de propósito general sino que la aplicación aprovecha las características del amplificador o, alternativamente, el amplificador se diseña para satisfacer los requerimientos de la aplicación. Finalmente, si bien cada arquitectura se dimensiona usando las mismas especificaciones generales de desempeño, también es verdad que cada una presenta un desempeño global específico y único. Estas diferencias pueden obtenerse y entenderse con simulación spice, toda vez que se usan adecuadamente los recursos de la herramienta de simulación. Todos los resultados obtenidos son a temperatura ambiente.
Determination of the natural frequencies of ultralight carbon fiber trusses for silicon tracking systems
Authors: Herrera M. , Ligdenova T. , Ceballos Sanchez Cesar , Dementev D.
Published: November 2024

In this work a method is developed to determine the natural frequency of highly-irradiated ultralight carbon fiber trusses. This method is based both in experimental acoustic measurements and the ANSYS-based modeling of the trusses. The structures under study are sensor supporting trusses widely used in silicon inner trackers of large experimental setups at LHC, FAIR and NICA.
First principles calculations of physical properties of the CeCu2Si2 material
Authors: Jabar A. , Idrissi S. , Tahiri N. , Bahmad
Published: November 2024

Using local density approximation functional computations, LSDA (local spin density approximation) and mBJ (modified Becke-Johnson) for exchange-correlation interactions, we examined the combination CeCu2Si2, concentrating on its many physical properties. This work used the WC-GGA method to compute the elastic characteristics of CeCu2Si2 material, and the results indicate that unstrained CeCu2Si2 is more brittle. The density of states exhibits the metallic character of the chemical, in agreement with the inference made from the band structure. We also assessed several optical characteristics, such as real and imaginary optical conductivity, electronic energy loss, absorption coefficient, refractive index, and extinction coefficient. We also looked at the electronic components of thermal conductivity, electrical conductivity, Seebeck coefficient, and electronic conductivity. The compound's Seebeck coefficient values are negative, indicating p-type behavior. A thorough analysis of the data is presented, along with important details regarding the CeCu2Si2 compound's characteristics.
Comparative analysis of performance, efficiency, and resource usage between COMSOL Multiphysics and the MPh library of Python in the simulation of physical phenomena
Authors: Ortiz Villicaña Marco Antonio , Huamani Tapia Yemby Yahaida , Guerrero Mendez Carlos Alejandro
Published: November 2024

MPh is a library of Python that makes possible to link the Python computer language with COMSOL Multiphysics. The use of the MPh library opens the possibility to save the computer resources employed when simulating physical phenomena and solving mathematical models and equations. In the Python command interpreter is possible to change or adjust some settings and parameters from the models created in COMSOL, and to execute the COMSOL kernel to solve those models. In this study, we compare the performance of COMSOL Multiphysics and the MPh library of Python when computing the magnetic field generated by a distribution of currents and ferromagnetic material. The metrics employed to do the comparison and the methodology to measure them are described, as well as the computer equipment where the programs ran. The results show that the execution time of the computations are similar in both software, but in the rest of the metrics, the execution in Python surpassed the execution in COMSOL. We showed that the MPh library of Python demands less CPU and RAM usage when solving the mathematical models and the files containing the solutions use less storage memory. As a conclusion, we propose the use of the MPh library of Python to improve the performance of the computer in charge of carrying out the calculations.
Theoretical model for analysis of elastic constants in orthotropic materials considering shear stress
Authors: Alves Alvaro Santos , Ribeiro Milton Souza , Ferreira Ernando Silva , Leyva Cruz Juan Alberto
Published: November 2024

Nowadays, a general theoretical model to describe the mechanical behavior of anisotropic or orthotropic materials is still an open challenge. In this study, we propose a new theoretical model to determine the elastic constants of these materials considering the shear components of the stress tensor. To analyze the consistency of new approach in biaxial stress state on thin films, we used data reported in the literature, based in the $\sin^2 \psi$ technique. For the first time, the shear modulus value equal to $G_{xz} = 0.3 GPa$, for a polycrystalline Au thin film, was calculated, in addition to other elastic constants. Finally, we demonstrate that the new proposal theoretical model considering shear stress can be useful to determine elastic constants in orthotropic materials from experimentally measured data.
A non-newtonian approach to geometric phase through optic fiber via multiplicative quaternions
Authors: Ceyhan Hazal , Özdemir Zehra , Kaya Nurkan Semra , Gürgil İbrahim
Published: November 2024

In this paper, we researched magnetic and electromagnetic curves in multiplicative Euclidean 3-space via multiplicative quaternion algebra. Firstly, we examined the geometric phase representation of the polarized light wave in the optic fiber by multiplicative Frenet frame. Using the quaternionic approaches, we were able to derive the magnetic curve equations and theorems. Then, three particular instances have been illustrated with examples of electromagnetic curves and magnetic field equations. Lastly, we provided an interpretation of the findings. With the help of the results, we were able to present an alternative viewpoint on the construction of trajectories (such as circular or spiral-like ones) that do not exist uniquely in the realm of physics.
Optoelectronic and thermodynamic properties of the Yttrium filled skutterudite YFe4P12
Authors: Ilhem Messaoudi S. , TOUIA Amina , Addou O.
Published: November 2024

In this work, we sought to understand the structural, electronic, optical, and thermodynamic properties of the compound YFe4P12 using the full-potential and linear augmented plane-wave method (FP-LAPW) based on density functional theory (DFT), our calculation of the lattice parameter of this compound YFe4P12 is reasonably in good agreement with the experimental results. Calculations carried out on the electronic band structure showed that the YFe4P12 compound is classified as a direct-gap Half- half-metallic in the minority spins. Moreover, optical properties, such as the optical absorption coefficient, real and imaginary parts of the dielectric function, optical conductivity, refractive index, and optical reflectivity have been studied. The effects of pressure and temperature on the lattice parameter, heat capacities, coefficients of thermal expansion, entropy, and Debye temperature were explored using the quasi-harmonic Debye model.
First-principle study origin of ferromagnetism in non-magnetic perovskite BaSnO3 doped with 2p-X (X=C, N)
Authors: Guendouz Atika , Driss-Khodja K. , Amrani B.
Published: November 2024

In this study, our goal is to analyze the origin of magnetization in non magnetic cubic structure perovskite BaSnO3 doped with 2p-X (X=C, N) using the full potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT).  For the exchange and correlation potential we have applied the generalized gradient approximation (GGA) and the GGA plus-modified Becke-Johnson potential (mBJ-GGA).   The results show that BaSnO3 doped with C then with N and finally with C and N exhibit half-metallic ferromagnetism behavior with the integer magnetic moment of 1, 2 and 3 μB per cell respectively. The origin of the ferromagnetism that occurs within these compounds is mainly caused by the p-p hybridization between 2p-impurities and its neighboring oxygen atoms. These results allowed to conclude that doped perovskite could provide a new type of materials, called half-metallic for future spintronic devices.
Complex band structure of two-dimensional thermal wave crystals
Authors: Romero-Ramos C. A. , Manzanares-Martinez Jesus , Soto-Puebla D. , Manzanares Martínez B.
Published: November 2024

We investigate the complex band structure of temperature oscillations in a two-dimensional thermal wave crystal. We use the Cattaneo-Vernotte heat model to describe the thermal properties. We apply the plane wave method to calculate the complex band structure of a square lattice composed of an infinite array of square bars. We find that a complete band gap exists across the whole Brillouin zone, where temperature oscillations are forbidden. This has potential applications in thermal management, thermal cloaking, and other areas.
НАПРУЖЕНО-ДЕФОРМОВАНИЙ СТАН MIG-ПАЯНИХ З’ЄДНАНЬ ОЦИНКОВАНИХ ТРУБ
Authors: Матвієнків О. М.
Published: November 2024

Основною проблемою з’єднання труб із цинковим покриттям дуговим зварюванням є забезпечення корозійної стійкості зварних швів та збереження захисного покриття на прилеглих до них ділянках. Дана проблема може бути вирішена шляхом застосування технології MIG-паяння, яка дозволяє забезпечити достатньо високу міцність з’єднань – практично на рівні з основним металом, а також зберегти цілісність захисного цинкового покриття завдяки значно меншому тепловому впливі у порівнянні з дуговим зварюванням. Напружено-деформований стан трубопроводів визначається характеристиками внутрішніх та зовнішніх навантажень, основним серед яких є внутрішній тиск. В даній роботі досліджується напружено-деформований стан MIG-паяних з’єднань оцинкованих труб імітаційним моделюванням та експериментально. Досліджувались MIG-паяні стикові з’єднання труб діаметром 150 мм із низьколегованої сталі, які навантажувались внутрішнім тиском величиною 9МПа. Визначення напружень та деформацій на стінках труб поблизу кільцевого шва виконувались методом тензометрії з використанням тензометричного реєструючого комплексу «SPIDER-8» та спеціально розробленого стенду. Результати досліджень показали, що при використанні V-подібної форми кромок найбільша локалізація кільцевих напружень виникає на зовнішній стінці труб між швом та основним металом. Для зменшення кільцевих напружень та зміни їхньої локалізації було проведено оптимізацію форми кромок. Встановлено, що найбільш оптимальною для стикових MIG-паяних з’єднань труб є X-подібна форма кромок та визначено її розміри. Встановлено, що використання запропонованого типу обробки кромок зменшує рівень залишкових напружень на 21% у порівняні зі стандартними кромками. Запропонована форма кромок дозволила зменшити величину кільцевих напружень та змінити їх локалізацію із зовнішньої на внутрішню стінку труби, що дозволить підвищить міцність MIG-паяних з’єднань та тривалість експлуатації.
Investigating the Healing Potential of Topical Phenytoin for Therapeutic Treatment in Thermal Burns
Authors: Chittoria Ravi Kumar
Published: November 2024

Thermal burn injuries impose significant physical and psychological distress, particularly in underdeveloped regions. Facilitating early wound healing is paramount to mitigate ensuing complications. Phenytoin, easily accessible, has emerged as a potential agent for expediting wound recovery. This study endeavors to assess the therapeutic efficacy of topical phenytoin in second and third-degree burn injuries. The research involved a 70-year-old female with thermal burns affecting both gluteal regions. Intravenous phenytoin solution was topically applied every two days. Data collection encompassed demographic details, tissue culture findings, wound discharge, pain intensity, granulation tissue formation, and wound contraction. Self-inflicted burns predominated the cases examined. Despite initial colonization with pathogenic bacteria, phenytoin treatment did not impede wound healing. Following 2-4 sessions, a significant reduction in wound discharge and pain relief were observed. Digital planimetry demonstrated progressive wound contraction across all cases. In conclusion, topical phenytoin application demonstrated efficacy in promoting wound contraction, re-epithelialization, and alleviating pain, thereby expediting wound healing. Furthermore, some cases exhibited a bacteriostatic effect. Nevertheless, further rigorous trials are imperative to validate these findings.
Advancements in Patient Care and Safety: Integrating Nursing Innovations for Enhanced Healthcare Outcomes
Authors: S. Ashi Rangappa
Published: November 2024

In the realm of virtual environments, hand haptic technology plays a crucial role in capturing the nuanced movements of a user’s hands and fingers. This is complemented by a haptic sleeve that bridges the gap between the arm and hand, effectively translating these movements into corresponding actions performed by a robot avatar within the virtual space. Furthermore, these innovative devices are adept at relaying the force and texture felt by the robot avatar as it interacts with objects in the virtual environment back to the user. This interaction crafts an immersive experience, mirroring the sensation of physically touching and manipulating the objects. The prediction of wearer's joint torques uses the Hill-type model and is made through the flexion movement of the elbow joint. As the user engages in object manipulation through the robot avatar, the haptic feedback disseminates throughout the entire arm, enriching the user experience with a wide spectrum of tactile sensations. This advancement in haptic technology significantly enhances the realism of robot operation, thereby improving the dynamics of human-robot interaction.
Knowledge, Attitude, and Practices regarding Prevention and Management of Under-five Diarrhea among mothers of Worawora Community
Authors: Alhassan Abdul Rauf
Published: November 2024

Background: Diarrheal illness continues to be the second greatest cause of under-five mortality worldwide. Diarrhea is responsible for roughly 1.5 million infant fatalities per year, or close to one in five. Aim: This current study was to assess knowledge, attitude, and practices regarding prevention and management of under-five diarrhea among mothers of Worawora Community. Methodology: A cross-sectional descriptive study was carried out using a total of 207 mothers with children less than 5 years. SPSS version 20 software was used for data analysis. Means, frequencies, and percentages were used for descriptive analysis and Pearson correlation for association with a set P value of 0.05. Results: The ages of the mothers ranged from 13 to 50 years, with a mean age of 27.70 ± 7.15 years. About 68.1% had good knowledge of diarrhea definition, causes, and prevention. The majority (74.4%) of the mothers had a good attitude. The majority had moderate food hygiene practices. About half (51.2%) had good hand-washing practices. About 34.3% had good home management of child diarrhea. Mothers' diarrhea prevention and management knowledge positively correlated with attitude, r(207) =.301, p < .001, hand hygiene practice, r(207) =.417, p < .001 and diarrhea management score, r(207) =.339, p < .001. Also, the attitude of respondents positively correlated with their practice scores for hand hygiene r(207) =.246, p < .001, and food hygiene r(207) =.299, p < .001. Finally, there was a significant correlation between mothers' hand hygiene practice and diarrhea management practice r(207) =.459, p < .001. Conclusion: Most of the respondents exhibited good knowledge and attitude toward under-five diarrhea management and prevention. However, the good knowledge and attitude did not translate to good practice and management in all of the respondents.
Optimizing Antibiotic Prophylaxis in Transurethral Resection of Bladder Tumors: Individualized Approaches and Future Direction
Authors: Anass Mehedra
Published: November 2024

Our findings consist of the importance of an individualized approach based on infectious risk and prudent antibiotic management to prevent antibiotic resistance, and highlight the need for further research to better assess the clinical impact of antibiotic prophylaxis in this specific context of transurethral resection of bladder tumor.
Risk of late radiation necrosis more than 5 years after stereotactic radiosurgery
Authors: McCall Neal S. , Lu Annabel , Hopkins Benjamin D. , Qian David , Hoang Kimberly B. , Olson Jeffrey J. , Zhong Jim , Eaton Bree R. , Shu Hui-Kuo G.
Published: November 2024

OBJECTIVE

Radiation necrosis (RN) is a well-recognized late complication most commonly occurring within 2 years of stereotactic radiosurgery (SRS); however, late RN (LRN), RN occurring or recurring > 5 years after SRS, has been poorly described. This study analyzes the incidence of and risk factors for LRN occurring > 5 years after SRS.

METHODS

This retrospective analysis included patients treated with linear accelerator–based SRS for tumors or arteriovenous malformations with > 5 years of clinical and serial MRI follow-up. LRN was defined as new neurological symptoms with neuroanatomically correlated imaging findings without disease recurrence. Univariate and multivariate analyses for LRN were performed using the Cox proportional hazards model.

RESULTS

The authors identified a cumulative 297 lesions in 219 patients treated to a median dose of 17 Gy with a median follow-up of 7.4 years. In total, 290 (97.6%) lesions were treated in a single fraction, and 64 (21.5%) were treated after resection. The LRN occurred in 19 (8.7%) patients and in 23 (7.7%) lesions at a median of 6.1 years (range 5.1–13.9 years) after SRS. Fifteen of the 23 (65.2%) lesions were managed with steroids, bevacizumab, and/or antiepileptic drugs. The remaining 8 (34.8%) were resected; histopathology confirmed necrosis without disease recurrence in each. On multivariate analysis, only > 5-cm3 volume of the brain receiving 12 Gy (brain V12Gy) (HR 6.01, 95% CI 1.77–20.48; p = 0.004) and a history of early, previously resolved RN (HR 9.53, 95% CI 2.00–45.61; p = 0.005) remained significantly associated with LRN.

CONCLUSIONS

RN risk persists well beyond 5 years after SRS, and recognizing LRN as an entity has important implications in managing these patients. LRN risk was highest in those with a brain V12Gy > 5 cm3 and a history of early RN after SRS, warranting close follow-up in perpetuity for select patients.
Characterization of cerebrospinal fluid markers as indicators of spinal cord ischemia following an endovascular aortic aneurysm repair procedure
Authors: Danilov Camelia A. , Yu James Y. H. , Gong Marvin , Han Sukgu M , Fleischman Fernando , Magee Gregory A. , Weaver Fred , Schönthal Axel H. , Chen Thomas C.
Published: November 2024

OBJECTIVE

Spinal cord ischemia (SCI) remains one of the most devastating complications in both open and endovascular stent graft repair of thoracoabdominal aortic aneurysms. The endovascular aortic aneurysm repair (EVAR) can be either thoracic (TEVAR) when it targets the thoracic aortic aneurysm or fenestrated branched when repair involves the visceral and/or renal arteries. Even though EVAR interventions are less invasive than open repair, they are still associated with a significant risk of SCI. The current primary strategy to prevent SCI after TEVAR is to increase and/or maintain spinal cord perfusion pressure (blood flow) by increasing the mean arterial pressure while simultaneously draining CSF. Although the benefit of CSF drainage in EVAR procedures remains uncertain, it provides an opportunity to study the changes in cytokine and oxidative stress markers that may signal the pathophysiology of SCI following EVAR. The aim of this study was to evaluate the temporal relationship between stent deployment and CSF cytokine and oxidative stress marker levels as predictors of delayed SCI in patients undergoing an EVAR procedure.

METHODS

There were 16 EVAR cases across 15 patients enrolled in this study, with 1 patient undergoing the procedure twice 1 year apart. The levels of oxidative stress (8-hydroxy-2′-deoxyguanosine [8-OHdG], glial fibrillary acidic [GFAP], and lactic acid) and proinflammatory (tumor necrosis factor–alpha [TNF-α], interleukin (IL)–6, and IL-1β) and antiinflammatory (IL-4) markers were quantified at different time points between 0 and 48 hours after EVAR by enzyme-linked immunosorbent assay. The changes in protein levels of both oxidative stress and inflammatory markers were expressed as fold change from the time of the lumbar drain insertion prior to surgery.

RESULTS

Following the EVAR procedure, 8-OHdG resulted in the highest upregulation at later time points postoperatively (48 hours) and this increase was positively correlated with TNF-α level. The data also revealed that IL-6 peaked during the stent deployment intervention and this pattern of expression was positively correlated with the expression of lactic acid. No significant changes were noted in the expression levels of GFAP, lactic acid, and IL-1β.

CONCLUSIONS

There appears to be a temporal relationship between lumbar CSF drainage and CSF cytokines and oxidative stress markers that may help 1) identify patients at risk for developing delayed SCI and 2) modify patient management to prevent the damage from delayed SCI.
Risk factors for wound dehiscence after surgery for epilepsy
Authors: Kagawa Kota , Iida Koji , Hashizume Akira , Seyama Go , Okamura Akitake , Askoro Rofat , Orihashi Yasushi , Akita Tomoyuki , Horie Nobutaka
Published: November 2024

OBJECTIVE

Wound dehiscence following craniotomy is a complication for which patients are subjected to additional procedures to achieve wound closure. During surgery for epilepsy, a craniotomy is performed at various sites to cure or palliate seizures in patients with intractable epilepsy. Collaborations between medicine and engineering have provided many surgical devices and materials for various stages of craniotomy, from skin incision to wound closure. The risk factors for wound dehiscence remain undetermined. Here, the authors attempt to identify risk factors associated with wound dehiscence after surgery for epilepsy.

METHODS

They retrospectively reviewed the clinical records and operative notes of consecutive patients with intractable epilepsy who had undergone craniotomy to allow resective or disconnective surgery between 2015 and 2023 in the Department of Neurosurgery, Hiroshima University Hospital, and had a minimum follow-up of 1 year. The authors conducted a multivariate logistic regression analysis to determine the risk factors for wound dehiscence.

RESULTS

The study population comprised 174 patients who had undergone corpus callosotomy (70 patients), cortical resection (CR; 65 patients), or CR via intracranial video electroencephalography monitoring (IVEEG; 39 patients). Wound dehiscence occurred in 14 patients (8.0%). Univariate analysis showed that wound dehiscence was associated with CR via IVEEG (p = 0.0330), electrocautery scalpels (p = 0.0037), T-shaped skin incisions (p = 0.0216), dural closure (p = 0.0002), and longer operative duration (p = 0.0088). Multivariate logistic regression analysis revealed that skin incision using an electrocautery scalpel (p = 0.0462, OR 9.38, 95% CI 1.04–84.74) and dural closure using nonabsorbable artificial dura (p = 0.0078, OR 6.29, 95% CI 1.63–24.31) were independent risk factors for wound dehiscence.

CONCLUSIONS

Surgical devices and materials contribute to wound dehiscence after epilepsy surgery. To avoid wound dehiscence, the use of an electrocautery scalpel is not recommended when performing skin incisions, nor is dural closure using a nonabsorbable artificial dura.
Laparotomy-assisted, two-port fetoscopic myelomeningocele repair: infant to preschool outcomes
Authors: Sanz-Cortes Magdalena , Whitehead William E. , Johnson Rebecca M. , Aldave Guillermo , Castillo Heidi , Desai Nilesh K. , Donepudi Roopali , Joyeux Luc , King Alice , Kralik Stephen F. , Lepard Jacob , Mann David G. , McClugage Samuel G. , Nassr Ahmed A. , Naus Claire , Nguyen Gabrielle , Castillo Jonathan , Ravindra Vijay M. , Sutton Caitlin D. , Weiner Howard L. , Belfort Michael A.
Published: November 2024

OBJECTIVE

This study reports the infant to preschool outcomes of a laparotomy-assisted, two-port fetoscopic myelomeningocele (MMC) repair and compares the results with those of a contemporary, same-center cohort that underwent either fetal MMC surgery via hysterotomy or postnatal MMC repair.

METHODS

All MMC closures between December 2011 and July 2021 were screened. Singleton pregnancies with hindbrain herniation and MMC between T1 and S1 were included. Fetuses were excluded for genetic abnormalities, severe kyphosis, and other congenital anomalies. The pregnant woman determined the method of MMC repair (fetoscopic, hysterotomy, or postnatal repair).

RESULTS

Two hundred MMC closures met the study criteria (100 fetoscopic, 41 hysterotomy, and 59 postnatal). The median length of follow-up was beyond 46 months for all groups. The median gestational age at delivery was 38.1 weeks (IQR 35.1, 39.1 weeks) for the fetoscopic group, 35.7 weeks (IQR 33.6, 37.0 weeks) for the hysterotomy group, and 38.6 weeks (IQR 37.7, 39.0 weeks) for the postnatal group. Vaginal delivery occurred in 51% of the fetoscopic cases, and there were no instances of uterine dehiscence or rupture. Treatment for hydrocephalus in the 1st year occurred in 35% (95% CI 27%–50%) of fetoscopic, 33% (95% CI 20%–50%) of hysterotomy, and 81% (95% CI 70%–90%) of postnatal repair cases. At 30 months, patients who underwent fetal intervention were twice as likely to be community ambulators (with or without devices) as those who underwent postnatal repair (52% [95% CI 42%–62%] of fetoscopic, 54% [95% CI 39%–68%] of hysterotomy, and 24% [95% CI 14%–36%] of postnatal cases). Surgery for symptomatic tethered cord occurred in 12% (95% CI 7%–19%) of fetoscopic, 17% (95% CI 8%–31%) of hysterotomy, and 2% (95% CI 1%–8%) of postnatal repair cases. Surgery for symptomatic spinal inclusion cysts was required in 4% (95% CI 1%–9%) of fetoscopic, 7% (95% CI 2%–18%) of hysterotomy, and none (95% CI 0%–8%) of the postnatal cases.

CONCLUSIONS

Laparotomy-assisted, two-port fetoscopic repair provides significant benefits for maternal health. It negates the risk of uterine rupture for the index pregnancy and subsequent pregnancies and allows for vaginal delivery. The benefits to the fetus are the same as those of hysterotomy repairs, with a lower risk of prematurity. There was no difference in the rate of surgery for tethered cord or spinal inclusion cysts between fetoscopic and hysterotomy procedures. Overall, laparotomy-assisted, two-port fetoscopic repair is safer for the fetus and the mother than fetal MMC surgery via hysterotomy.
Indication-based analysis of laser interstitial thermal therapy: a propensity score–matched comparison of outcomes for brain tumor versus epilepsy indications
Authors: Miller Andrew M. , Shahrestani Shane , Michel Michelot , Yu John S. , Mamelak Adam
Published: November 2024

OBJECTIVE

Laser interstitial thermal therapy (LITT) is a minimally invasive procedure used to ablate abnormal tissue in a targeted fashion. It is most commonly used to treat epileptic foci, brain tumors, and radiation necrosis. This study aimed to compare immediate postoperative outcomes between these indications.

METHODS

This study analyzed clinical data from the Nationwide Readmissions Database (NRD) from 2016 to 2019 and identified 2234 patients who underwent LITT procedures using ICD-10 codes. The authors analyzed patient demographics, complications, discharge disposition, readmission rates, and mortality. Following propensity score matching, 317 patients treated for epilepsy and 323 patients treated for brain tumors were compared.

RESULTS

The mean ages were similar (epilepsy: 45.7 vs tumor: 49.0 years, p = 0.55), as were the proportions of female patients (epilepsy: 45.4% vs tumor: 52.9%, p = 0.83), all-payer costs (p = 0.81), income quartiles (p = 0.58), insurance types (p = 0.70), frailty rates (p = 0.85), and comorbid disease burdens as assessed by ECI score (p = 0.73). No significant differences were observed in rates of hemorrhage (p = 0.1), pulmonary embolism (p = 0.32), or infection (p = 0.16). However, the tumor cohort had higher rates of deep vein thrombosis (3.4% vs < 3.15%, p = 0.045), nonroutine discharge (26.6% vs 16.4%, p = 0.04), and 1-year hospital readmission (32.5% vs 18.6%, p = 0.006). One-year mortality rates were similar (tumor: 3.4% vs epilepsy: < 3.15%, p = 0.08).

CONCLUSIONS

While postoperative complications and 1-year mortality rates were similar among patients undergoing LITT for epilepsy and brain tumors, the tumor cohort experienced higher rates of deep vein thrombosis, nonroutine discharge, and 1-year hospital readmission.
Stereotactic robot–assisted MRI-guided laser interstitial thermal therapy thalamotomy for medically intractable Holmes tremor: a pilot study and literature review
Authors: Aubignat Mickael , Tir Mélissa , Ouendo Martial , Boussida Salem , Constans Jean-Marc , Lefranc Michel
Published: November 2024

OBJECTIVE

Holmes tremor (HT) is a complex syndrome characterized by resting, postural, and kinetic tremors. HT significantly impacts patients’ quality of life (QOL) and daily activities. Conventional pharmacological treatments for HT often yield inconsistent results. Emerging surgical treatments such as deep brain stimulation and various thalamotomy techniques show promise but come with challenges, including adverse events (AEs) and potential tremor recurrence. This study aimed to evaluate the clinical outcomes of unilateral MRI-guided laser interstitial thermal therapy (MRIgLITT) thalamotomy in patients with medically intractable HT, focusing on tremor reduction, QOL, and AE incidence, and provide a comprehensive review of the literature on thalamotomy techniques for HT.

METHODS

Five patients with medically intractable HT underwent unilateral MRIgLITT thalamotomy between June 2020 and January 2023. Tremor severity was assessed using the Fahn-Tolosa-Marin Tremor Rating Scale (TRS) at baseline and at 3 and 12 months postoperatively. QOL was measured using the Quality of Life in Essential Tremor (QUEST) questionnaire and 39-item Parkinson’s Disease Questionnaire (PDQ-39). Subjective patient-rated improvement was evaluated using the Patient Global Impression of Clinical Status (PGI-C) scale at 12 months. Cognitive performance was assessed using the Mini-Mental State Examination (MMSE) before the procedure and at 12 months postoperatively. AEs were monitored throughout the follow-up period.

RESULTS

The mean patient age was 50.2 ± 22.37 years, with a mean tremor duration of 5.8 ± 4.55 years. Significant tremor reduction was observed in the treated hand, with mean TRS scores decreasing from 19.00 ± 4.36 at baseline to 11.20 ± 4.44 (p = 0.043) at 3 months and 13.40 ± 5.94 (p = 0.042) at 12 months, indicating a relative reduction of 41.05% and 29.47%, respectively. A significant effect was observed on the QUEST scale at 3 months (p = 0.043), but this effect was no longer present at 12 months. No significant effect was found on the PDQ-39 QOL scale. The PGI-C scale showed a high mean subjective improvement of 88.60% ± 8.36% at 12 months. One patient experienced severe AEs, including dysarthria, hemiparesis, and swallowing difficulties, which required prolonged hospitalization and multidisciplinary rehabilitation, but regressed within 3 months. Cognitive performance, as measured by the MMSE, remained stable (p = 0.785).

CONCLUSIONS

Unilateral MRIgLITT thalamotomy showed promise as a treatment for medically intractable HT, providing significant tremor reduction with a favorable safety profile. However, the potential for tremor recurrence and minimal functional improvement in fine motor skills highlight the need for long-term follow-up and further research. Larger, multicenter studies are necessary to validate these findings.
Development of a murine laser interstitial thermotherapy system
Authors: Frain Matthew , Thomas Nagheme , Yan Sandra C. , Karachi Aida , Dastmalchi Farhad , Ebrahim Ghaidaa , Rajon Didier , Tyc Richard , Flores Catherine , Chauhan Anjali , Sayour Elias , Mitchell Duane A. , Bova Frank J. , Rahman Maryam
Published: November 2024

OBJECTIVE

The objective of this study was to develop a murine system for the delivery of laser interstitial thermotherapy (LITT) with probe-based thermometry as a model for human glioblastoma treatment to investigate thermal diffusion in heterogeneous brain tissue.

METHODS

First, the tissue heating properties were characterized using a diode-pumped solid-state near-infrared laser in a homogeneous tissue model. The laser was adapted for use with a repurposed stereotactic surgery frame utilizing a micro laser probe and Hamilton syringe. The authors designed and manufactured a stereotactic frame attachment to work as a temperature probe stabilizer. Application of this novel design was used as a precise method for real-time thermometry at known distances from the thermal ablative center mass during murine LITT studies.

RESULTS

Temperature measurements were achieved during LITT that verified the direct thermometry capability of the system without the need for MR-based thermal monitoring. Application of multiple stereotactic design iterations led to an accurately reproducible surgical laser ablation procedure. Histological staining confirmed precise thermal ablation and controllable lesion size based on time and temperature control. Treatment of a syngeneic intracranial glioma model highly resistant to conventional therapy resulted in a modest survival benefit.

CONCLUSIONS

The authors have successfully developed a murine model system of LITT with direct in situ thermometry for investigation into the effects of thermal ablation and combinatorial treatments in murine brain tumor models.
Evaluating laser interstitial thermal therapy for newly diagnosed, deep-seated, large-volume glioblastoma: survival and outcome analysis
Authors: Khalafallah Adham M. , Shah Khushi H. , Knott Maxon V. , Berke Chandler N. , Shah Ashish H. , Komotar Ricardo J. , Ivan Michael E.
Published: November 2024

OBJECTIVE

Laser interstitial thermal therapy (LITT) has emerged as an alternative for treating glioblastoma (GBM) in patients deemed unsuitable for resection due to deep-seated or eloquent location, age, or comorbidities. However, its safety and efficacy in large-volume, deep-seated, newly diagnosed GBM (nGBM) tumors remain insufficiently studied. Therefore, the authors aimed to assess the outcomes of LITT in the treatment of deep-seated, large-volume nGBM.

METHODS

A retrospective analysis of patients with nGBM who underwent LITT between February 2013 and August 2023 was conducted. Patients with deep-seated tumor volume ≥ 10 cm3 treated with LITT were compared to patients with deep-seated tumor volume < 10 cm3. Demographic, perioperative, and follow-up data were collected and compared among both groups. Kaplan-Meier survival analysis and Cox proportional hazards regression were performed to evaluate the impact of various clinical and treatment-related factors on patient survival.

RESULTS

A total of 33 patients in the study group (mean ± SD age 65.7 ± 10.2 years, 58% male) with mean tumor volume 36.0 ± 21.6 cm3 were compared to 23 controls (mean age 67.0 ± 12.5 years, 61% male) with mean tumor volume 5.2 ± 2.7 cm3. There were no significant differences in hospital length of stay (p = 0.494), temporary neurological deficits and edema within 30 days (p = 0.705 and p > 0.999, respectively), 30-day readmissions (p = 0.139), < 30-day complications (p = 0.918), complications between 30 days and 3 months (p = 0.903), and new motor and speech deficits within 3 months (p = 0.883 and p > 0.999, respectively) between the study and control groups. Kaplan-Meier analysis did not reveal any statistically significant difference in overall survival (OS) between groups (p = 0.227). Multivariate analysis indicated that tumor volume did not significantly affect the hazard ratio for individuals undergoing LITT (HR 1.16, 95% CI 0.83–3.29, p = 0.150).

CONCLUSIONS

This pilot study suggests that LITT is safe for treating patients with large-volume, deep-seated nGBM compared to those with small-volume tumor. Although there appears to be improved OS in patients with smaller lesions with greater EOA, significance was not achieved in this cohort.
An analysis of functional outcomes following laser interstitial thermal therapy for recurrent high-grade glioma
Authors: Wilhelmy Bradley , Serra Riccardo , Chen Chixiang , Mishra Mark , Rodrigues Dario , Badjatia Neeraj , Motta Melissa , Ksendzovsky Alexander , Woodworth Graeme F.
Published: November 2024

OBJECTIVE

Laser interstitial thermal therapy (LITT) is an emerging tool for treating a variety of focal brain lesions, including recurrent high-grade glioma (HGG). While the efficacy and uses of LITT have been well studied, the impact of this treatment on patient functional outcomes has not been analyzed in detail. This study sought to better define the role of LITT in treating patients with recurrent HGG, examining which patients exhibit good functional outcomes after LITT, and to determine risk factors for worsening neurological function.

METHODS

The medical records of patients treated with LITT for recurrent HGG at a single tertiary care center were retrospectively reviewed. Functional status was assessed using the Karnofsky Performance Scale (KPS). Demographic, clinical, and radiological data were examined for associations with change in KPS score assessed 4–6 weeks following surgery.

RESULTS

Forty-seven patients were included in the study with histopathologically confirmed recurrent HGG. The mean age was 57 years, and 21 (45%) patients were female. The pre-LITT KPS scores were as follows: 100 in 4 (9%) patients, 90 in 15 (32%) patients, 80 in 10 (21%) patients, 70 in 13 (28%) patients, and 60 in 5 (11%) patients. Overall, 59% of patients showed a stable or improved KPS score after undergoing LITT. Tumor volume was the sole predictor of decreased KPS score after LITT. Notably, tumor location including eloquent location, preoperative KPS score, and other comorbidities were not independently associated with change in functional status.

CONCLUSIONS

The majority of patients undergoing LITT for recurrent HGG had a favorable functional outcome at the initial follow-up visit. The treated tumor volume was inversely and independently associated with post-LITT functional outcome. This information may help guide patient selection and treatment optimization in the setting of LITT-based approaches for recurrent HGG.
Anomalous venous collaterals in Apert and Crouzon syndromes and their relationship to ventricle size and increased intracranial pressure
Authors: Cuperus Iris E. , Mulders Jip Y. , Dremmen Marjolein H. G. , de Planque Catherine A. , Mathijssen Irene M. J. , Van Veelen Marie-Lise C.
Published: November 2024

OBJECTIVE

The exact association between the frequently present anomalous intracranial venous vasculature, emissary collaterals, ventriculomegaly, and increased intracranial pressure (ICP) in children with Apert and Crouzon syndromes remains an enigma. This study aimed to evaluate the association between the aberrant venous system and ventricle size and increased ICP, and to assess the development of the venous structures over time.

METHODS

This retrospective cohort study included all patients with Apert or Crouzon syndrome with available CT venography (CTV) scans of the brain. Anomalous venous vasculature was assessed by the total collateral score (TCS), which scored 9 intra- and extracranial venous structures (TCS range 0–16). Ventricle size (fronto-occipital horn ratio [FOHR]) was measured on the same scan. The presence of increased ICP, a shunt, tonsillar herniation, and head circumference were extracted from electronic patient records and were used as secondary covariates. Subsequent CTV scans were scored when available.

RESULTS

Ninety patients were included in this study. The mean TCS was 7.5 ± 2.5, and was comparable for patients with Apert and Crouzon syndromes (mean 8.0 and 7.3, respectively). The presence of an extra abnormal venous structure was associated with an increase of the FOHR of 3.2% (p < 0.01). After dividing the venous structures into intra- and extracranial, a similar association between both and the FOHR was found (4.1% and 2.3%, respectively; p < 0.01). The TCS was similar for patients with normal and increased ICP at the time of the scan. Sixteen patients had dual CTV scans. The median time between both scans was 3.2 years. The presence of collaterals remained stable over time (median ΔTCS = 0.3). Seven patients with functioning shunts also maintained high TCSs (median TCS = 9).

CONCLUSIONS

In patients with Apert and Crouzon syndromes, a close relationship between venous collaterals and ventricle size was observed, in which a more extensive aberrant venous drainage pattern, both intra- and extracranial, was associated with larger ventricles. Preliminary longitudinal data suggested that the presence of venous collaterals remained constant over time despite effective treatment of increased ICP, indicating reliance on these collaterals even in cases of normal ICP. The authors hypothesize that this dependence on collateral drainage is the result of their aberrant internal venous anatomy and predisposes individuals to increased ICP.
New records and morphology of Chrysococcus furcatus (Chrysophyceae, Chromulinales) in the waterbodies of the Southern Ural
Authors: Snit’ko L. V. , Snit’ko V. P.
Published: November 2024

The data on new records ofChrysococcus furcatusvegetative cells and stomatocysts obtained using scanning electron microscopy (SEM) are presented. The species has been recorded for the first time in the Urals; three habitats were discovered during extensive multiyear sampling. The originality of the research lies in the study of the environmental conditions of cell growth and mass formation of stomatocysts in natural waterbodies, as well as in obtaining information on the increase in silicon content in mature stomatocysts using energy-dispersive X-ray spectroscopy. In the Southern Ural population, the morphotypes of stomatocysts with an obconical long collar of varying length are found. Some specimens had a single needle-like spine bifurcating when mature, located on or very close to the posterior pole. A new form with multiple needle-like spines located on the posterior pole of stomatocyst has been discovered. The rest of the cyst body was ornamented with conical scabrae. Descriptions are illustrated with electron micrographs. The obtained results supplement the information on the algal flora of Russia and can be used in environmental monitoring of waterbodies and paleoreconstructions.
Cyperus microiria (Cyperaceae), a new alien species for the Caucasus
Authors: Vishnyakov V. S.
Published: November 2024

The first findings ofCyperus microiria, an alien species with a natural range in South and Southeast Asia, are reported for the Caucasus. The species was initially discovered in collections from Adjara stored in the Herbarium of the Batumi Botanical Garden (BATU), and then was re-collected by the author from the same region in 2023. The first collections from the territory of the Botanical Garden, where the species entered presumably due to the introduction of subtropical Asian plants, date back to 1987. Currently, it is a fairly common species in disturbed wet habitats of the coastal lowland. The nearest findings were made in Rize, Turkey, where the species was recorded as naturalized only in 2014.