The Effect of Hydrocephalus on the Optic Nerve in the Presence of Intracranial Mass.

OBJECTIVE: The measurement of optic nerve sheath diameter is a noninvasive, practical, and economical method used to identify increased intracranial pressure. The purpose of this study is to detect the preoperative and postoperative changes in optic nerve sheath diameter in patients with intracranial mass, to correlate these changes with optic nerve diameter variations, and to evaluate the impact of hydrocephalus on these alterations. MATERIAL AND METHOD: This study was conducted with patients who presented to our clinic with complaints of intracranial mass, were decided for surgery, and underwent surgical procedures. FINDINGS: The optic nerve and optic nerve sheath diameter measurement values were different preoperatively and postoperatively, with a significant decrease in the optic nerve sheath diameter in all groups in postoperative measurements, while the optic nerve diameter significantly increased. CONCLUSIONS: Although there was no significant difference between the effects of hydrocephalus and intracranial mass-related increase in intracranial pressure on the optic nerve and optic nerve sheath, it was observed that hydrocephalus increased intracranial pressure when considering the Evans ratio. It has been determined that as ventricular dilatation increases, so does intracranial pressure, which leads to an increase in the diameter of the optic nerve sheath, resulting in papilledema and thinning of the optic nerve. These findings indicate the importance of early cerebrospinal fluid diversion and monitoring optic nerve sheath diameter in the management.

Effects of municipal sludge composition on hydrothermal liquefaction products: Aqueous phase characterization and biodegradability assessment.

Hydrothermal liquefaction (HTL) aqueous phases derived from mixed sludge and digested sludge of two wastewater treatment plants (WWTP) were characterized considering variations in primary-secondary sludge ratios, an aspect previously overlooked in the literature. Mixed sludge was obtained by mixing primary and secondary sludge to simulate high primary sludge, average, and high secondary sludge cases. Aerobic and mesophilic/thermophilic anaerobic biodegradability tests were conducted. Higher chemical oxygen demand, total ammonium-N, orthophosphate-P, fatty acids, and N-heterocycles in HTL aqueous samples were detected as the secondary sludge ratio increased in mixed sludge. A similar trend was observed in the biodegradability tests. Characteristics of HTL aqueous derived from mixed sludge of WWTP 1 showed much higher variation, whereas WWTP 2 mixed sludge was not affected significantly by primary-secondary sludge ratios. Finally, the biodegradability levels of HTL aqueous samples were determined to be 69-78 % under aerobic, 58-70 % under mesophilic anaerobic, and 42-56 % under thermophilic anaerobic conditions.

Characterization of the Mechanical, Biodegradation, and Morphological Properties of NBR/Biopolymer Blend, Integrated with a Risk Evaluation.

Biopolymer blends have attracted considerable attention in industrial applications due to their notable mechanical properties and biodegradability. This work delves into the innovative combination of butadiene-acrylonitrile (referred to as NBR) with a pectin-based biopolymer (NGP) at a 90:10 mass ratio through a detailed analysis employing mechanical characterization, Fourier transform infrared (FTIR) analysis, thermogravimetric analysis (TGA), and morphology studies using SEM. Additionally, biopolymer's biodegradability under aerobic and anaerobic conditions is tested. The study's findings underscore the superior tensile strength and elongation at break of the NGP/NBR blend in comparison to pure NBR, while also exhibiting a decrease in puncture resistance due to imperfect bonds at the particle-matrix interfaces, necessitating the use of a compatibilizer. In anaerobic conditions, evaluation of biodegradable properties reveals 2% and 12% biodegradability in NBR and NGP/NBR blend, respectively. The degradation properties were also aligned with TGA results highlighting a lower decomposition temperature for NGP. Additionally, this research integrates the application of a conditional value-at-risk (CVaR)-based analysis of the blend's tensile properties to evaluate the uncertainty impact in the experiment. Under risk, a significant enhancement in the tensile performance (by 80%) of the NGP/NBR blend was shown compared to pure NBR. Ultimately, the study shows that adding pectin to the NBR compound amplifies the overall performance of the biopolymer significantly under select criteria.

Evaluation of on-site biological treatment options for hydrothermal liquefaction aqueous phase derived from sludge in municipal wastewater treatment plants.

Aerobic treatment, mesophilic anaerobic digestion, thermophilic anaerobic digestion, and dark fermentation were evaluated for on-site biological treatment of municipal sludge derived HTL aqueous. For all four described batch test scenarios, municipal sludge-derived HTL aqueous samples obtained under 290-360 °C and 0-30 min retention time were used. In the aerobic respirometric tests, HTL aqueous samples resulted in a five-day biochemical oxygen demand range of 40.75 g/L (350 °C-25.6 min) to 54 g/L (325 °C-0 min). The calculated aerobic biodegradability index showed that approximately 50 % of the organics in HTL aqueous were easily biodegradable. Mesophilic and thermophilic biochemical methane potential tests resulted in specific yields of 151-179 mL CH4/g chemical oxygen demand (COD) and 103-122 mL CH4/g COD, respectively. HTL aqueous obtained under 360 °C-15 min condition caused total inhibition in both mesophilic and thermophilic anaerobic digestion. Possible causes for this inhibition were pyridine, pyrrolidinone, piperidinone, pyridinol, and phenolic compounds, which were higher in abundance in the 360 °C-15 min sample. HTL aqueous was found unfit for hydrogen production in dark fermentation due to inhibitory composition. In summary, on-site biological treatment of HTL aqueous was found to be most suitable under aerobic and mesophilic anaerobic conditions.

An improved plastination method for strengthening bamboo culms, without compromising biodegradability.

Biomaterials are increasingly being designed and adapted to a wide range of structural applications, owing to their superior mechanical property-to-weight ratios, low cost, biodegradability, and CO2 capture. Bamboo, specifically, has an interesting anatomy with long tube-like vessels present in its microstructure, which can be exploited to improve its mechanical properties for structural applications. By filling these vessels with a resin, e.g. an applied external loading would be better distributed in the structure. One recent method of impregnating the bamboo is plastination, which was originally developed for preserving human remains. However, the original plastination process was found to be slow for bamboo impregnation application, while being also rather complicated/methodical for industrial adaptation. Accordingly, in this study, an improved plastination method was developed that is 40% faster and simpler than the original method. It also resulted in a 400% increase in open-vessel impregnation, as revealed by Micro-X-ray Computed Tomography imaging. The improved method involves three steps: acetone dehydration at room temperature, forced polymer impregnation with a single pressure drop to - 23 inHg, and polymer curing at 130 °C for 20 min. Bamboo plastinated using the new method was 60% stronger flexurally, while maintaining the same modulus of elasticity, as compared to the virgin bamboo. Most critically, it also maintained its biodegradability from cellulolytic enzymes after plastination, as measured by a respirometric technique. Fourier transform infrared-attenuated total reflection, and thermogravimetric analyses were conducted and showed that the plastinated bamboo's functional groups were not altered significantly during the process, possibly explaining the biodegradability. Finally, using cone calorimetry, plastinated bamboo showed a faster ignition time, due to the addition of silicone, but a lower carbon monoxide yield. These results are deemed as a promising step forward for further improvement and application of this highly abundant natural fiber in engineering structures.

Biochar and wood ash amended anaerobic digestion of hydrothermally pretreated lignocellulosic biomass for biorefinery applications.

This study investigated the effect of biochar and wood ash amendment on the anaerobic digestion of hydrothermally pretreated lignocellulosic biomass. Hydrothermal pretreatment was performed on switchgrass at 200, 250, and 300 °C with 0, 30, and 60 min of retention times. The pretreatment method was optimized using the response surface method for enhanced methane production. At the optimum pretreatment (200 °C/0 min retention time), a specific methane yield of 256.9 mL CH4/g volatile solids (VS), corresponding to an increase of 32.8% with respect to the untreated substrate, was obtained. Hydrothermal pretreatment was beneficial for methane production at temperatures lower than 220 °C and retention times shorter than 20 min. At more severe pretreatment conditions than 220°-20 min, sugars were degraded into other products, causing a decrease in the methane yield. The hydrothermal degradation products, i.e., acetic acid, lactic acid, furfural, and hydroxymethylfurfural concentrations, were also measured and modeled. The addition of biochar and wood ash to BMP assays were tested at 2, 9, 16 g/g VSinoculum ratios and <63, 63-125, 125-250 µm particle sizes. A decline in methane production was observed for all tested doses and particle sizes of both additives. The decline in the methane potential was proportional to the doses and particle sizes. Kinetic modeling of BMP test results also supported that using the additives was not beneficial. Based on the result of this study, it was found that the use of biochar and wood ash in a pretreated lignocellulosic biomass processing biorefinery would not be beneficial.

Exogenous Amylase Reverses Cerebral Ischemia Induced by Selective Intraarterial Injection of Degradable Starch Microspheres: An Angiographic and Histological Study in a Novel in Vivo Animal Model.

AIM: To validate a new particulate embolization method using degradable starch microspheres (DSM) and intraarterial exogenous amylase administration, which allow for regulated temporary cerebral arterial embolization without compromising tissue perfusion. MATERIAL AND METHODS: Twenty-four male New Zealand rabbits were randomly divided into three groups. All animals underwent routine angiography. The control group received no additional intervention. In the ischemia group, 0.2ml DSM was administered to the animals via the right carotid artery with pulsed, gentle injections to induce ischemia in the cerebral microcirculation. Animals in the reperfusion group received 0.05 ml of exogenous amylase along with DSM administration. Six hours after the procedure, the animals were sacrificed and histopathological analysis was performed. RESULTS: The ischemia group was the most adversely affected group by embolization, with the highest number of pyknotic neurons. The reperfusion group, which received exogenous amylase, had lower pyknotic neurons than the ischemia group. The pyknotic neuron count was similar in some regions between reperfusion and control groups. CONCLUSION: Exogenous amylase can rapidly attenuate cerebral ischemia caused by microembolization with DSM.

Does Gross Total Resection Improve Progression-Free and Overall Survival in Pediatric Intracranial Ependymomas? Single-Center Clinical Experience Of 61 Cases.

OBJECTIVE: To share our clinical experience of 25 years and identify prognostic factors for progression-free and overall survival in pediatric intracranial ependymomas. METHODS: In total, 61 children who were treated between 1995 and 2020 in a single institution were included in the study. Medical records of the patients were retrospectively reviewed to obtain and analyze the following data: patient age at first surgery, sex, presenting symptoms, hydrocephalus and any invasive treatment, anatomic site, extent of resection, pathologic grade, time to progression, and time to death. Progression-free and overall survival rates and affecting factors were analyzed by Kaplan-Meier method. RESULTS: Dysphagia, number of surgeries, and spinal seeding were associated with progression free and overall survival in univariate analysis. The extent of resection, World Health Organization grade, and visual problems were also associated with progression whereas sex was associated with overall survival. Cox regression identified the extent of resection and single surgery as an independent prognostic factor for progression-free survival. No independent factor was found for overall survival. CONCLUSIONS: This single center experience of 25 years confirms the beneficial effect of gross total resection on disease progression. Although spinal seeding seems to affect survival rates, greater number of cases are needed to reveal its full effect.

Enhancement of lignocellulosic biomass anaerobic digestion by optimized mild alkaline hydrogen peroxide pretreatment for biorefinery applications.

Lignocellulosic energy crops are promising feedstocks for producing renewable fuels, such as methane, that can replace diminishing fossil fuels. However, there is a major handicap in using lignocellulosic sources to produce biofuels, which is their low biodegradability. In this study, the application and the optimization of a lignocellulose pretreatment process, named alkaline hydrogen peroxide, was investigated for the enhancement of methane production from the energy crop switchgrass. Four independent process variables, solid content (3-7%), reaction temperature (50-100 °C), H2O2 concentration (1-3%), and reaction time (6-24 h), and three response variables, soluble reducing sugar, soluble chemical oxygen demand, and biochemical methane potential were used in process optimization and modeling. The optimization was performed by two different approaches as maximum methane production and cost minimization. The optimum conditions for the highest methane production were found as 6.65 wt% solid content, 50.6 °C reaction temperature, 2.94 wt% H2O2 concentration, and 16.05 h reaction time. The conditions providing the lowest cost were 6.43 wt% solid content, 50 °C reaction temperature, 1.83 wt% H2O2 concentration, and 6.78 h reaction time. For maximum methane production and cost minimization, specific methane yields of 338.52 mL CH4/g VS and 291.34 mL CH4/g VS were predicted with 62.4 % and 39.8 % enhancements compared to untreated switchgrass, respectively. Finally, it was found that the predicted methane production for the maximum methane production represents 77 % of the theoretical methane yield and 82.22 % energy recovery.

Hydrochar derived from municipal sludge through hydrothermal processing: A critical review on its formation, characterization, and valorization.

Additional options for the sustainable treatment of municipal sludge are required due to the significant amounts of sludge, high levels of nutrients (e.g., C, N, and P), and trace constituents it contains. Hydrothermal processing of municipal sludge has recently been recognized as a promising technology to efficiently reduce waste volume, recover bioenergy, destroy organic contaminants, and eliminate pathogens. However, a considerable amount of solid residue, called hydrochar, could remain after hydrothermal treatment. This hydrochar can contain abundant amounts of energy (with a higher heating value up to 24 MJ/kg, dry basis), nutrients, and trace elements, as well as surface functional groups. The valorization of sludge-derived hydrochar can facilitate the development and application of hydrothermal technologies. This review summarizes the formation pathways from municipal sludge to hydrochar, specifically, the impact of hydrothermal conditions on reaction mechanisms and product distribution. Moreover, this study comprehensively encapsulates the described characteristics of hydrochar produced under a wide range of conditions: Yield, energy density, physicochemical properties, elemental distribution, contaminants of concern, surface functionality, and morphology. More importantly, this review compares and evaluates the current state of applications of hydrochar: Energy production, agricultural application, adsorption, heterogeneous catalysis, and nutrient recovery. Ultimately, along with the identified challenges and prospects of valorization approaches for sludge-derived hydrochar, conceptual designs of sustainable municipal sludge management are proposed.

Azathioprine as a Neuroprotective Agent in Experimental Traumatic Spinal Cord Injury.

AIM: To evaluate the protective effects of azathioprine, a macrophage-inhibiting agent, on secondary injury in spinal cord trauma. MATERIAL AND METHODS: A total of 40 Wistar rats were randomly divided into 4 groups. All the animals had undergone T8-10 laminectomy. Except in group I (control), all the animals were exposed to spinal cord trauma at the T9 level. Animals in group II (trauma) received no treatment following trauma. Animals in group 3 (treatment) and group IV (vehicle) were given intraperitoneal azathioprine 4 mg/kg and saline 2 ml, respectively, 30 minutes after the trauma. Half of the animals in each group were sacrificed 24 hours after injury and specimens were used for biochemical and immunohistochemical evaluations. The rest of the animals were followed-up for 4 weeks in terms of neurological functions and were also sacrificed to perform the histopathological analysis. RESULTS: Significant decrease in apoptotic cells and improved neurological function were observed in the animals treated with azathioprine. Biological and immunohistochemical analysis also showed less oxidative stress in this group compared to those without treatment. CONCLUSION: Azathioprine, a potent macrophage-inhibiting agent, has been shown to decrease the extent of secondary injury following spinal cord trauma.

The effect of pentoxifylline on cerebral vasospasm following experimental subarachnoid hemorrhage.

OBJECTS: Cerebral vasospasm is an important event that occurs following subarachnoid hemorage which has significant mortality and morbidity. The goal in this study was to investigate the effect of pentoxifylline on vasospasm in an experimental subarachnoid hemorrhage model. METHODS: In this study, 20 male New Zeland White rabbits weighing 3000-3500 g were assigned randomly to four groups. Animals in group 1 served as controls. Animals in group two received only intravenous pentoxifylline injection 3 times in 12 h intervals. In group 3, SAH was induced and no injection was given. Animals in group 4 received intravenous pentoxifylline (6 mg/kg) injections 3 times at 12th, 24th and 36th hours after subarachnoid hemorrhage induction. All animals were sacrificed and basilar arteries were removed at 48th hour. Basilar artery vessel diameters, wall thicknesses and luminal section areas were measured with Spot for Windows version 4.1. Statistical analysis was performed using ANOVA and Kruskall-Wallis tests. RESULTS: Mean basilar artery luminal section areas and luminal diameters in group 4 were significantly higher compared to group 3 (p < 0.05). Basilar artery wall thicknesses and were found to be higher in group 3 than in other groups and this was also statistically significant (p < 0.05). CONCLUSION: Our study demonstrated that intravenous administration of pentoxifylline significantly decreases vasospasm after subarachnoid hemorrhage.

Comparison of ependymomas and medulloblastomas located in the posterior cranial fossa: An anatomical and histopathological study.

Posterior fossa tumors (PFTs) include medulloblastomas, atypical teratoid/rhabdoid tumors, pilocytic astrocytomas, ependymomas, and brainstem gliomas. We evaluated patients with surgery at our clinic, comparing epidemiological, clinical, radiological, and pathological characteristics of medulloblastoma and ependymoma to identify factors that might assist preoperative diagnosis, help to develop treatment algorithms, and have prognostic value after surgery. Pediatric patients from 0 to 16 and young adults from 16 to 29 years of age with surgery for pathologically confirmed ependymomas or medulloblastomas between January 2014 and January 2020 were eligible. The study included 19 patients, seven with ependymoma (37%) and 12 with medulloblastoma (63.2%). The ependymoma patients were 5.29 ± 5.85 years of age, the medulloblastoma patients were 11.58 ± 8.17 years of age, and 16 patients (84%) were children.Fifteen patients (79%) presented with signs of increased intracranial pressure and four (21%) presented with cerebellar findings. MRI found that 74% (14) of the PSTs were located in the midline, including six of the seven ependymomas (86%) and eight of the 12 medulloblastomas (67%). Enhancement was significantly greater in medulloblastomas compared with ependymomas (p = 0.022). In according to pathology results; synaptophysin, NSE, chromogranin and 50% GFAP positivity were observed in medulloblastoma. Ependymomas were S100 (43%) and vimentin (29%) positive. Ependymoma patients were younger than medulloblastoma patients and more were female. There were no significant differences in the clinical findings, but ependymomas were larger and had greater rates of enhancement and spinal metastasis compared with medulloblastomas.

Long-Term Outcomes of Pediatric Meningioma Surgery: Single Center Experience with 23 Patients.

AIM: To evaluate the long-term outcomes and prognostic variables in a surgical cohort of pediatric meningiomas treated in a single institution. MATERIAL AND METHODS: Medical records and follow-up notes of 23 pediatric patients aged < 18 years (12 male and 11 female; mean age on presentation, 13.1 ± 4.4 years) harboring 27 meningiomas operated between 1994 and 01/2019 at Hacettepe University Ihsan Dogramaci Children’s Hospital were evaluated. RESULTS: One patient had neurofibromatosis (NF) type 1, and five patients had NF2. Tumors were most commonly located in the convexity (n=6) and parasagittal or falcine (n=6). Gross total resection was performed in 70.4% of cases. WHO grade I tumors accounted for 56% of all cases, whereas high-grade meningiomas accounted for 44% (33% grade II, 11% grade III). The mean follow-up duration was 10.3 ± 7.7 years. Three patients (13%) died during follow-up, and 76.2% of the patients had favorable outcome (Glasgow Outcome Scale > 3) during the last follow-up assessment. Ten patients (43.5%) had relapse. In univariate analysis, low histological grade (p=0.030) and gross total resection (p=0.024) were associated with favorable outcome. The 10-year overall survival rate was 86%. CONCLUSION: Meningiomas in the pediatric age group are surgically treatable tumors with fairly good outcomes. However, relapses are common even for low-grade tumors; therefore, long-term surveillance and aggressive treatment are needed.

Survival Benefit with Gross Total Resection and Adjuvant Radiotherapy in Childhood Atypical Teratoid/Rhabdoid Tumors: Results of a Single-Center Cohort of 27 Cases.

AIM: To share a single center experience with 27 atypical teratoid/rhabdoid tumor (AT/RT) cases, and to determine the effect of gross total tumor resection and other clinical characteristics on the overall survival rate of AT/RT. MATERIAL AND METHODS: We included 27 patients-with a histopathologically confirmed primary intracranial childhood AT/ RT-who were operated in our clinic between January 2000 and December 2017. Age, sex, tumor location, disseminated disease, the presence of hydrocephalus, symptom duration till diagnosis, the extent of resection, and adjuvant radiotherapy were evaluated for their influence on overall survival. RESULTS: Median age at diagnosis for 27 patients was 19.1 months (7.2 months-5 years). Gross total resection was possible in 13 (48.72%) patients. Except for three patients who died of perioperative complications, all patients received chemotherapy and 11 received radiotherapy. In univariate analysis, male sex, older age at diagnosis (≥24 months), gross total resection, and radiotherapy were associated with overall longer survival; however, radiotherapy remained the only significant parameter in multivariate analysis. CONCLUSION: AT/RT is a rare and dreadful brain tumor that has low survival rates despite contemporary treatment. Radiotherapy seems to prolong survival; however, large-scale studies are needed to establish prognostic factors.