Reduction In Area Research Articles

Experimental and Numerical Investigation on the Bearing Capacity of Axially Compressive Concrete-Filled Steel Tubular Columns with Local Corrosion

This study aims to examine the effects of local corrosion on the axial compression performance of concrete-filled steel tubular (CFST) members. Nineteen CFST short columns with local corrosion were designed and fabricated to undergo axial compression mechanical property tests, with the radial corrosion depth of the local corrosion area as the key test parameter. The failure mechanism and mechanical property change laws of CFST axial compression short columns with circumferential full corrosion at the ends and middle were studied. Combined with finite element modeling, the influence laws of the three-dimensional geometrical characteristics of the local corrosion zone, i.e., the axial length, the annular width and the radial depth, on the structural bearing performance were thoroughly explored and discussed. The results revealed that the main reason for the reduction in load-carrying capacity of circular CFST axial columns due to local corrosion is attributed to the reduction of the effective cross-sectional area of the steel tube in the corrosion area. When local corrosion occurs at different axial positions, the variation range of the bearing capacity of CFST columns is within 10%. Regarding the impact of the three dimensions of local corrosion on the axial load-carrying capacity of CFST, the radial corrosion depth was identified as the most influential factor, followed by the annular corrosion width, and finally by the axial corrosion length. When the axial corrosion length exceeds 20% of the specimen length, its further influence on the load-carrying capacity is considered limited. Finally, a practical calculation formula for the bearing capacity of locally corroded CFST columns is proposed. The predicted results of this formula fit well with the test results and can quickly estimate the remaining bearing capacity of the structure by measuring the geometric parameters of the local corrosion area, providing a reference for the assessment and maintenance of CFST structures.

Abstract 4132838: Coronary Collaterals Provide Cardioprotection in Hemorrhagic ST-elevation MI (STEMI)

Introduction: Development of intramyocardial hemorrhage (IMH) in acute STEMI following reperfusion is estimated to affect 35-50% of patients. IMH is a lethal event as it contributes to larger MI size, compromised myocardial salvage, adverse left ventricular (LV) remodeling, lower LVEF, and consequential major adverse CV events post-MI. Whether coronary collateral circulation reduces the deleterious effects of IMH has not been investigated. Hypothesis: We hypothesized that coronary collaterals could reduce the extent of post-reperfusion IMH volume and offer cardioprotection to hemorrhagic MI patients. Methods: MIRON-CL (NCT05898425) recruited and studied STEMI patients (n=294) reperfused via PCI. Pre-PCI coronary angiography allowed for assessment of collateral vessels using the Rentrop grading system, from Grade 0 (no collaterals) to Grade III (complete collateral filling). Post-PCI cardiac MRI, performed 3 days later, was used to determine area affected (extent of myocardial edema) from T2 maps, extent of IMH from T2* maps and MI size from LGE as %LV. Statistical analyses were used to examine relationships between collateral grades, MI size, IMH, and area affected. Results: 124 patients were hemorrhagic and 170 were non-hemorrhagic. Patients with no collaterals (Grade 0; CL-) exhibited significantly higher IMH volumes (7.41 ± 5.33% LV) compared to those with collaterals (Grade I: 5.23 ± 3.21% LV, Grade II: 3.11 ± 2.78% LV, Grade III: 2.05 ± 1.89% LV; p<0.001). Total area affected post-PCI was larger in CL- (37.62 ± 15.32% LV) compared to CL+ (21.48 ± 13.21% LV, p<0.001). Presence of collateral circulation (Grade>0 combined; CL+) was correlated with smaller MI sizes (CL-: 38.66 ± 14.63% LV vs. CL+: 19.84 ± 13.72% LV, p<0.001) and reduced MVO volumes (CL-: 8.07 ± 6.60% LV vs. CL+: 2.17 ± 2.35% LV, p<0.001). Patients with no collaterals had a significantly higher adj. risk of IMH (OR: 5.71, 95% CI: 3.16-10.33, p<0.0001). Conclusion: Coronary collaterals reduce post-reperfusion IMH volume in STEMI patients and provide significant cardioprotection: reductions in area affected, MVO and MI size. Insight into collateral grade offers opportunities to improve risk stratification and management of revascularized STEMI patients.

Niosomal gel improves dermal delivery of nimbolide: a promising approach for treatment of psoriasis.

Aim: Psoriasis is a chronic inflammatory skin disorder characterized by the excessive proliferation of keratinocytes, forming thickened skin plaques due to immune-mediated cytokine responses. Delivering drugs through this barrier to target inflamed tissues remains challenging. Nimbolide (NIM), known for its anti-inflammatory and anticancer properties, shows promise in managing psoriasis. However, its efficacy is limited by its inability to penetrate the thickened horny layer of the skin. To overcome this obstacle, we have developed Nim-loaded niosomal (Nio) formulations (NIM Nio) aimed at improving dermal delivery and achieving localized sustained release at psoriasis-affected sites.Methods: The formulation characteristics were assessed using Zeta sizer, Transmission Electron Microscopy (TEM), and High-performance liquid chromatography (HPLC). The optimized formulation was evaluated for anti-psoriatic potential compared to Nim alone by using molecular techniques such as Confocal Microscopy, Flow cytometry, enzyme-linked immunosorbent assay (ELISA), and Western blotting.Results: NIM Nio showed effective penetration into psoriatic skin, resulting in reductions in keratinocyte hyperproliferation, oxidative stress, splenomegaly, inflammatory cytokines, Psoriasis Area and Severity Index (PASI), and rete ridges compared to NIM alone.Conclusion: Our findings underscore the significant anti-proliferative, antioxidant, and anti-inflammatory properties of NIM Nio in psoriasis, demonstrating its potential as a promising therapeutic option for this challenging condition.

A Study of Loss Model Parameter Sensitivity in Compressor Unsteady Flow Simulations

Abstract This article presents results from a comprehensive sensitivity analysis focused on loss models used in a recently developed compressor unsteady mean line flow model for a transonic axial-centrifugal compressor. The mean line flow model treats flow through rotors and stators in their respective reference frames (rotating or stationary), and the compressor performance is determined by the kinetic energy addition and various physics-based loss models in relative frames. In this paper, we describe the modeling approach of the compressor flow model, as well as the loss models that are used to obtain a relatively good match against test data. Sensitivity studies of selected loss model parameters are presented to show the effect of individual loss model parameters on the overall compressor characteristics in the entire speed range. The effects of losses on unsteady flow transients are assessed by comparing the transient responses when a step reduction of throttle area is applied. The comparisons show that the change in loss magnitude has weak effects on transient response if the change of loss does not significantly change the system stability.

Effects of land use changes on local dust event in Urmia Lake basin

Land use change is an effective factor in climate change and global warming, which contributes to the carbon cycle, radiant energy balance, and dust production. Urmia Lake basin water balance in the Northwestern part of Iran is in a critical condition due to land use change, drought, and climate change. This process has led to the lake water area reduction and pronounced dust production. The satellite images indicate that from 1984 to 2017, 1433 Km2 rangelands and water area of the Urmia Lake basin decreased by more than 2906 Km2. The area of human settlement increased by 550 Km2, irrigated farmland and orchards, 804 Km2, and salty marsh, 3428 Km2. The outputs of the WetSpass hydrological model reveal the highest coefficient of evapotranspiration and interception variation in the East of Urmia Lake basin. The effects of these changes are observed in reduced soil moisture, increased salty marsh, and soft sediments as potential dust resources. During the study period, the frequency of dust days in the North and East of the lake increased 2.5-fold, while in the Southern and Western parts increased 6-fold. The results of the Pettitt Test indicate that these changes began to appear in 2007. The regression and correlation test confirm that salt marshes and soft sediments account for up to 75 %, and the decrease in the area of Urmia Lake for more than 64 % of the dust changes. The results of the assessments indicate the contribution of footprint in the destruction of the natural environment and the water balance of the lake basin. Revision of water resources management and environmental water rights of the lake, changes in the development strategy from agriculture to non-agriculture development based on lower water demand, and reduction of storage dams are among the recommended strategies to address this problem.

Winging it: hummingbirds alter flying kinematics during molt.

Hummingbirds are well known for their hovering flight, one of the most energetically expensive modes of locomotion among animals. Molt is a costly event in the annual cycle, in which birds replace their feathers, including all their primary feathers, which, in hummingbirds, comprise most of the area of the wing. Despite this, the effects of molt on hovering flight are not well known. Here, we examined high-speed videos (14 individuals of three species from the Colombian Andes recorded at 1200 frames per second) comparing molting and non-molting hummingbirds' wing kinematics and wingtip trajectories. We found that molting hummingbirds rotated their wings in more acute angles during both downstroke and upstroke compared to non-molting individuals (10° versus 20°, and 15° versus 29°, respectively), while other flight parameters remained unchanged. Our findings show that hummingbirds are capable of sustaining hovering flight and thereby maintaining their weight support even under impressive wing area reductions by adjusting their stroke amplitudes.

DISTRIBUSI SEDIMEN PADA WADUK JATIBARANG, KOTA SEMARANG

The main issue in the operation of reservoirs is sedimentation. This can lead to silting and affect the reservoir's storage capacity. The distribution of sediments needs to be understood in order to gain an overview of their spread, so that measures can be taken to address sediment-related issues in the Jatibarang Reservoir. The analysis was conducted using sediment data from previous studies, which reported a total sediment volume of 6.64 million m³ over a period of 50 years. Based on topographic data, it was found that the Jatibarang Reservoir is classified as Type III, with a "hill" classification. The analysis results showed that the dimensionless factor F is 0.22, with a relative depth p of 0.53. Based on the sediment distribution analysis of the Jatibarang Reservoir with Empirical Area Reduction Method, it was found that after 50 years of operation, the new zero elevation of the reservoir would be at an elevation of +126.82 m. In comparison with the low water surface elevation at the existing dead storage of the Jatibarang Reservoir, which is at +136 m, it can be concluded that the Jatibarang reservoir can operate according to the planned lifespan and can still function for more than 50 years

Enhanced Macrophages Engulfment by Peptide‐Templated Nanoassemblies Targeting SIRPα and Suppressing Oxidative Stress for Atherosclerosis Pro‐Efferocytotic Therapy

AbstractPrompt removal of apoptotic cells via macrophage‐mediated efferocytosis is an emerging approach for atherosclerosis treatment, because these diseased cells directly contribute to vascular inflammation and secondary necrosis in plaques. Despite blocking CD47 can restore impaired efferocytosis by inhibiting “don't eat me” signals, the currently available CD47 antibody (CD47‐Ab)‐based therapy may accelerate off‐target clearance of healthy cells due to the ubiquitous expression of CD47 on viable cells. Here, a peptide‐templated nanoassembly (PTna‐1) engineered to induce synergistic enhancement of engulfment by macrophages is reported. Through self‐assembled polypeptides with multiple functional motifs, the nanoassembly can specifically target p32‐overexpressing macrophages and bind to the Ig‐V‐like domain of SIRPα but not to CD47, thereby normalizing intraplaque efferocytosis and alleviating persistent inflammation. Concurrently, disassembled PTna‐1 released manganese porphyrins with photoacoustic/magnetic resonance imaging capability to suppress oxidative stress and synergistically enhance macrophage phagocytosis through the RhoA/ROCK1 pathway. Compared with CD47‐Abs, PTna‐1 promoted a more significant reduction in lesion area and plaque stabilization without affecting the incidence of anemia in atherosclerotic mice. Proteomic analysis revealed that PTna‐1 treatment decreased the expression of inflammation‐related proteins in plaques. Overall, these peptide‐driven nanoassemblies employing a SIRPα‐specific blockade strategy provide a distinct paradigm of pro‐efferocytotic therapy for atherosclerosis.

Waste collection route optimisation for the second waste-to-energy plant in Budapest

The city of Budapest produces approximately 680–700 000 tonnes of municipal solid waste every year, of which <2/3 is being recycled or used for energetic purposes, the rest ends up in a landfill. To combat this environmental and logistical problem the installation of a second waste incineration plant has been proposed in the south of the city. The only cost associated with fuel consumption in the case of waste to energy powerplants (WtE plants) is the transport cost, as the city council provides economic support for waste disposal. Since the transportation has a huge influence on the cost of opertation, logistical optimisation of the transport routes promises a direct impact on cost savings. In this study the logistical optimisation of the Southern Budapest area was carried out using image processing and logic based algorithm programming. As a result the optimal transport of 230 000 tonnes of municipal solid waste (MSW) was solved resulting in a 4 835.2 km monthly travel distance reduction.This value can be translated to 7 823 €/month cost, 9 459.6 kg/month CO2 and 45.3 kg/month NOx emissions reduction in the urban areas.

Study on resistance performance of hexagonal hull form with variation of angle of attack, deadrise, and stern for flat-sided catamaran vessel

Abstract The flat-sided hull vessel was designed with the purpose of simplifying hull production by eliminating the requirement for fairing, bending, and assembly of curved panel lines. Nevertheless, implementing the flat hull concept may marginally increase the hull resistance. The objective of the study is to investigate the impact of the hexagonal hull concept on resistance characteristics when altering the deadrise angle, angle of attack, and stern angle. Additionally, the resistance performances of the proposed hexagonal hulls were compared to evaluate the influence of the hull design geometry parameter. The contribution of this work is to identify the configuration of the design parameters to achieve an ideal level of resistance in a hexagonal catamaran hull design. The findings indicate that a greater angle of attack could potentially enhance wave generation and increase the resistance. Despite the increase in the wave resistance coefficient caused by the increment in deadrise angle, the overall resistance was reduced due to the significant reduction in wetted surface area resulting from the greater deadrise angle. As a result, the decrease in friction resistance was more pronounced than the increase in wave resistance. At last, the stern angle can cause a substantial oscillation in the curved line, resulting in a large increase in wave generation and overall resistance, particularly at high speeds.

Analyzing Monterrey blue/green infrastructure for the mitigation of heat islands using Earth Observation and WUDAPT method

Abstract. The Metropolitan Area of Monterrey has grown excessively along with its population in recent decades, resulting in an urban area with problems of distribution of spaces and services. In addition to this, factors such as pollution resulting from industrial activities and the reduction of green areas are related to the increase in temperatures in the area and the creation of urban heat islands, which are mitigated by the cooling action provided by the green/blue infrastructure of urban rivers. Because the rivers in the study area do not have a continuous channel throughout the year and the water supply problems that have recently worsened due to the drought in the north of the country, the riparian vegetation of its 3 rivers (Pesqueria, Santa Catarina and La Silla) plays a crucial role in reducing temperatures by acting as a natural heat sink, so its conservation and restoration is essential. In this research, the influence of rapid urbanization on the deterioration of rivers during 2003, 2013 and 2021 was evaluated using Google Earth Engine and the WUDAPT scheme for local climatic zones, finding that there is a correspondence between local climatic zones and fluctuations in temperature. The results obtained over a period of approximately two decades indicate that natural climate zones register lower temperatures compared to impervious surfaces, and that there is also considerable variation between areas with dense green/blue infrastructure and natural covers with little or no vegetation, since the latter have temperatures similar to those of the built classes.

Analisa dan Pemetaan Kepadatan Hutan Mangrove di Wilayah Pesisir Pantai Gresik

The mangrove forest ecosystem in Ujung Pangkah sub-district plays a very important role in the lives of living creatures around it. The management and use of mangrove ecosystems by people in this sub-district tends to lead to the conversion of land into ponds, whether in the form of forest or emerging land. Cutting down trees in mangrove gforests is one of the causes of abrasion in several areas in Indonesia. Apart from abrasion, there is also accretion or addition of land around the Bengawan Solo estuary which provides access to the Pangkahwetan and Pangkahkulon coasts. The aim is to analyzezchanges in the area of mangrove vegetationgin Ujungpangkah. This research uses a remote sensing method known as the resolution concept, namely spatial resolution, temporal resolution, spectral resolution, radiometric resolution and layer resolution. Quantitative observations were made of changes in mangrove forest area using Landsat -8 imagery. The location of the Ujungpangkah ground is based on the conditions of the study location, in accordance with the results of initial image processing. Changes in the area of mangrove vegetation when viewed from remote sensing results in 2023 and 2024 experience visible differences, the distribution of mangroves will increase in 2024, namely there will be an increase in the area of vegetation. The distribution area of mangroves always changes every year. Either in the form of addition or reduction of area. Things that can affect the extent of mangrove distribution include 2 types of damage to the mangrove ecosystem in Ujung Pangkah District, namely abrasion and deforestation. The efforts made to overcome this problem include starting mangrove planting activities in the Banyuurip Mangrove Center (BMC) area. The results of data processing from the 2023 RBI map in Ujungpangkah District recorded a total area of ​​11904.93052 ha. The area is divided into several land uses, namely Mangrove covering an area of ​​1253.24609 ha and Non-Mangrove covering an area of ​​1525.32660 ha. Meanwhile, processing data from Lansat-8 in 2024 in Ujungpangkah District, the total area was recorded at 11904.93052 ha. Mangrove land use was recorded at 10651.68443 ha and non-mangrove land at 10379.60392 ha.

Altered callosal morphology in post-stroke cognitive impairment

Stroke is the second leading cause of death and cognitive impairment. Post-stroke cognitive impairment (PSCI) is one of the most common sequelae among stroke survivors, yet its underlying neural mechanisms remain largely unclear. The corpus callosum (CC) plays a crucial role in interhemispheric integration and hemispheric segregation, with changes in CC morphology potentially overlapping with the spectrum of PSCI. This study aimed to investigate the morphological changes in the CC and their diagnostic value in PSCI patients. Structural MRI, neurobehavioral, and clinical data were collected from 104 PSCI patients and 54 demographically matched healthy controls. Significant reductions in CC area, circularity, and genu thickness were observed in PSCI patients, with these changes strongly correlating with global cognitive function. Subgroup analysis revealed that CC circularity significantly decreased when lesions were located in the posterior circulation, while both CC area and circularity markedly decreased with anterior circulation lesions. Receiver Operating Characteristic analyses identified the midbody areas of the CC as having high diagnostic value, with area under the curve values of 0.748 and 0.746, respectively. Further validation analyses suggest that the transcallosal fibers in these CC subregions are connected to the premotor, dorsal attention, and frontoparietal system. These findings show that areal CC atrophy in PSCI patients, particularly in regions with transcallosal connections to the premotor cortex and frontoparietal network, parallels global cognitive impairment. This suggests that CC morphology may serve as a potential imaging marker for the diagnosis and prognosis of PSCI.

Risk factors for postoperative ileus after corrective spinal surgery: association with reduction in the retrocrural space area.

The objective of this study was to determine whether a reduction in the retrocrural space (RCS) area is a risk factor for postoperative ileus (POI) in patients with adult spinal deformity (ASD) treated with spinal corrective surgery. In total, 100 patients (mean age 67.5 ± 8.3 years, 9 males and 91 females) with ASD treated with spinal corrective surgery were included in this study. Spinal parameters, including thoracolumbar kyphosis (TLK), and RCS area were measured pre- and postoperatively. The change (Δ) in spinal parameters was calculated. The percent change between pre- and postoperative RCS areas was calculated as ΔRCS. Patients were identified as having POI if they exhibited both gastrointestinal symptoms and radiographic findings. Each parameter was compared between patients with and without POI. Multivariable logistic regression analysis was performed with development of POI as the dependent variable. The incidence of POI was 11.0%. The RCS area was significantly smaller in the POI group than in the non-POI group (p < 0.001). Multivariable logistic regression analysis revealed that ΔTLK and ΔRCS were risk factors for POI (p = 0.029 and p = 0.033, respectively). A reduction in the RCS area is a risk factor for the development of POI after corrective spinal surgery in patients with ASD. Overcorrection of the thoracolumbar junction should be avoided to prevent POI.

Variation of Corrosion Characteristics and Tensile Performances of WE43 Alloy Under Marine Atmospheric Environment.

This study aims to examine the variation in corrosion characteristics and tensile properties of WE43 magnesium alloy in an actual marine atmospheric environment by means of outdoor exposure tests. The macroscopic corrosion morphology, microstructure, and tensile properties were analyzed. The results indicated that WE43 alloy will corrode rapidly during exposure under marine atmospheric environmental conditions, resulting in a loose and porous Mg(OH)2 layer on the surface. The Mg matrix was mainly consumed as an anode, leading to the occurrence of corrosion pits. With the increase in exposure time, both the tensile strength and plasticity of WE43 alloy gradually deteriorated. After exposure for six months, the elongation and area reduction were significantly reduced, with a reduction ratio of more than 50%. After 18 months of exposure, the ultimate strength of the alloy decreased from 359 MPa to 300 MPa. According to an analysis of fractures in the alloy, the corrosion pits on the sample surface were the main reason for the decrease in tensile properties.

Improvements in Hemodynamics and Right Heart Remodeling Following Balloon Pulmonary Angioplasty Treatment in Patients With Chronic Thromboembolic Pulmonary Hypertension: A Retrospective Study.

This study aimed to evaluate the hemodynamic alterations and right heart remodeling dynamics in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) undergoing treatment with balloon pulmonary angioplasty (BPA). This retrospective cohort study involved a cohort of 31 patients with a confirmed diagnosis of CTEPH. Comprehensive clinical evaluations were systematically performed before BPA, and at 3 and 6 months following the procedure. Significant clinical progress was evidenced by the uplift in the percentage of patients achieving WHO-FC II, escalating from 19.35% at baseline to 51.61% at 6 months after BPA (p = 0.003). NT-proBNP levels significantly dropped from a median of 614.6 to 69.9 pg/mL(p < 0.001). Hemodynamic assessments showed significant decreases in mean PAP from 45.53 ± 11.19 to 22.56 ± 5.81 mmHg (p < 0.001) and PVR from 8.33 to 2.86 WU (p < 0.001). Echocardiographic analysis revealed substantial reductions in the right atrial area (RAA, from 20.29 ± 7.55 to 16.79 ± 4.82 cm2, p < 0.001) and right ventricular internal diameter (RVID, from 4.13 ± 0.79 to 3.68 ± 0.59 cm, p = 0.001) at the 3-month interval post-BPA. These improvements were sustained or even enhanced by the 6-month mark, with RAA and RVID further diminishing (to 14.46 ± 3.78 cm2 and 3.29 ± 0.54 cm, respectively; both p < 0.01). The TAPSE/PASP ratios showed progressive improvement from baseline (0.32 ± 0.13) to 3 months (0.42 ± 0.13) and continued to improve at 6 months following BPA (0.50 ± 0.11, p = 0.04 compared to 3 months post-BPA). BPA has significantly ameliorated clinical conditions, hemodynamic profiles, and initiated a continued reversal in right heart remodeling in patients with CTEPH.

The Potential Role of Phytoplankton Functional Groups Under Anthropogenic Stressed Wetlands: Characterizing The Environmental Sensitivity.

Anthropogenic and climatic changes are continuously altering the freshwater plankton, necessitating an evaluation of the complex structure of plankton communities to understand and mitigate these impacts. In this context, the present study focuses on evaluating the structure of plankton communities, specifically Phytoplankton Functional Groups (FGs) for assessing the environmental sensitivity of wetlands under changing scenario. These FGs are defined by shared adaptive features rather than taxonomic traits. Over the period from 2016 to 2018, two ecologically distinct wetlands were examined, analysing their phytoplankton FGs and their relationship with water quality parameters. Ecohydrological data revealed significant seasonal variations (p ≤ 0.05) in key parameters such as water depth, temperature, pH, electrical conductivity, dissolved oxygen, total alkalinity, total hardness, NO3-N, and PO4-P. Notably, there were no significant differences observed among the sampling stations within each wetland. A total of 125 phytoplankton genera/species were classified into 23 FGs in the open wetland and 22 FGs in the closed wetland. Spatial and seasonal analyses of dominant FGs suggested both wetlands were experiencing pollution pressures. This study highlights the powerful role of phytoplankton functional groups (FGs) as bioindicators of wetland health, uncovering pollution pressures. In open wetlands, 15 phytoplankton FGs with 36 key taxa (Indicator Value ≥ 40%) emerged as critical indicators, while in closed wetlands, only 10 FGs with 17 taxa were identified. To assess eutrophication, the occurrence of these indicator species was evaluated using BVSTEP function analysis. The study recommends pollution reduction in catchment areas and restoration of riverine connectivity to enhance FG diversity. Phytoplankton FG methodologies are deemed effective for assessing the environmental sensitivity of wetlands significantly impacted by human activities. This research offers a scientific foundation for the evaluation and restoration of wetland ecosystems.

On the large-scale vortices in an L/D = 2.30 serpentine diffuser with internal bump

In this paper, the generation and spatial evolution of large-scale vortices in an ultra-compact serpentine diffuser (L/D = 2.30) featuring an integrated internal bump are experimentally and numerically investigated. Due to reduction of the local flow area caused by the internal bump, a favorable streamwise pressure gradient is induced first and then followed by an adverse one. Concurrently, a high-pressure region exists on the side of the diffuser as it contracts, yielding a sideward circumferential pressure gradient and then an inward one. Such circumferential pressure gradients divert the boundary layer on the windward side of the internal bump to the side and induce a spanwise U-shaped vortex on the leeward side, which constrains the development of flow separation in this region. The circumferential pressure gradients further induce two pairs of streamwise vortices located at the top and bottom of the diffuser, respectively. These vortex pairs entrain the low-energy fluids and transport them to the aerodynamic interface plane (AIP), resulting in two pairs of low-total-pressure regions and swirling flows. Moreover, in the experimentally studied range of the exit Mach number MAIP from 0.293 to 0.546, the distributions of low-total-pressure regions and swirl angles at the AIP exhibit a small variation, indicating that the internal flow field structures are insensitive to MAIP.

Raman, Judd-Ofelt and Photoluminescence Analysis of Ho3+/Yb3+-Doped Borotellurite Glasses for Potential Laser Applications

In this study, glasses with the composition (79-x) B2O3-xTeO2-20Li2O-0.5Ho2O3-0.5Yb2O3 (x = 0 - 50mol%) were synthesized using the melt-quenching method to explore the spectroscopic effect of TeO2 and B2O3 as mixed glass formers. Raman spectroscopy indicated that increasing TeO2 content leads to depolymerization, characterized by a reduction in the relative area of TeO4 units. Absorption spectra revealed nine peaks related to transitions from 5I8 ground state to various excited states of Ho3+ ions, and one peak for the transition from the 2F7/2 ground state of Yb3+ ions. A negative bonding parameter suggests that there is primarily ionic interaction among Ho3+ and its ligands. However, the increase of Ω2 suggests that Ho3+ ions have relatively higher covalence and strong ligand polarizability, except at x = 40mol% due to the rivalry among TeO2 and B2O3. Decrease in Ω4 and Ω6 reflect reduced glass rigidity due to increased NBO content, weakening the glass structure. Luminescence spectra showed green (526nm) and red (642nm) emissions from Ho3+ transitions of 5F4 → 5I8 and 5F5 → 5I8. Intriguingly, a novel peak at 738nm associated with the 5F4 → 5I7 transition in Ho3+ ions, linked to energy transfer from Yb3+ to Ho3+. The stimulated emission cross section for the green and red emission were (0.324 – 0.347) × 10-20 cm2 and (0.387 – 0.423) × 10-20 cm2 respectively. These glasses demonstrate potential for advanced laser, green display, and photonic technology applications.

Retrolabyrinthine approach to the lateral skull base: The value of preoperative temporal bone CT analysis

PurposeThe most used neurosurgical approach to reach cerebellar-pontine angle is the retrosigmoid route. This article describes the presigmoid approach which requires excellent knowledge of the labyrinthine block together with quantitative analysis of temporal bone CT. MethodsCT-based quantitative measurements were obtained in patients undergoing vestibular neurectomy with a presigmoid approach. Eighteen patients were enrolled, and five measures were taken: Trautmann’s area, the petro-clival angle, presigmoid dura length and its angle. The relationship between these measurements and hospitalization days, operating times, and complications was explored. ResultsThe posterior semicircilar canal (PSC)-sigmoid sinus (SS) distance, presigmoid dura- internal auditory canal (IAC)-PSC angle, and duration of surgery are predictors of complications. Specifically, a PSC-sigmoid sinus distance <11 mm, a dura presig-IAC-PSC angle <14 are associated with the highest risk of complications. ConclusionPreoperative temporal bone CT scan can guide the surgeon through the narrowest areas of the surgical approach. Trautmann’s triangle area and petro-clival angle reduction are challenging and can be faced with combined microscopic-endoscopic technique, and with optics angulation-rotation. The retrolabyrinthine approach can enable hearing preservation and minimal cerebellar retraction.