This paper describes synthetic rock mass (SRM) modeling, a new approach for simulating the mechanical behavior of jointed rock mass. This technique uses the bonded particle model for rock to ...represent intact material and the smooth-joint contact model (SJM) to represent the in situ joint network. The macroscopic behavior of an SRM sample depends on both the creation of new fractures through intact material and slip/opening of pre-existing joints. SRM samples containing thousands of non-persistent joints can be submitted to standard laboratory tests (UCS, triaxial loading, and direct tension tests) or tested under a non-trivial stress path representative of the stresses induced during the engineering activity under study.
Output from the SRM methodology includes pre-peak properties (modulus, damage threshold, peak strength, etc.) and post-peak properties (brittleness, dilation angle, residual strength, fragmentation, etc.). Of particular interest is the ability to obtain predictions of rock mass scale effects, anisotropy, and brittleness, properties that cannot be obtained using empirical methods of property estimation. This paper presents the theoretical background of the SRM approach along with some example applications.
Abajo: se repite los tres en el resumen. This work studies the effect of high-level fish meal replacement with insect meal: YW meal (obtained from Tenebrio larvae fed a broiler diet), BSF meal (from ...hermetia larvae fed broilers diet), BSFm meal (obtained from hermetia larvae fed discard fish) on growth performance nutritive indices and in vitro digestibility of Dicentrarchus labrax juvenile. Three different insect meals were used: BSF meal from hermetia larvae fed broilers diet; BSF improve (BSFm) obtained from hermetia larvae fed discarded fish; YW meal obtained from the larvae of Tenebrio fed a broiler diet. Five diets were used, a control (C) diet and four experimental diets by replacing fishmeal with insect meal from BSF at 30% and 50% (BSF30 and BSF50) substitutions, BSFm at 50% substitution (BSF50 m) and YM at 50% substitution (YW50). Nutritional and growth indices worsened by including insect meal, especially for hermetia meal at 50% substitution, BSF50 and BSF50 m. The internal organs’ weight reflected the growth of the fish fed each experimental diet. No differences were found in fillet composition. Nevertheless, under our experimental condition, YW replacement obtained better results than both BSF diets.
Transgranular microcracking is fundamental for the initiation and propagation of all fractures in rocks. The geometry of these microcracks is primarily controlled by the interaction of the imposed ...stress field with the mineral elastic properties. However, the effects of anisotropic elastic properties of minerals on brittle fracture are not well understood. This study examines the effects of elastic anisotropy of quartz on the geometry of brittle fracture and related acoustic emissions (AE) developed during indentation experiments on single crystals at ambient pressure and temperature. A Hertzian cone crack developed during blunt indentation of a single crystal of flawless Brazilian quartz parallel to the c axis shows geometric deviation away from predictions based on the isotropic case, consistent with trigonal symmetry. The visible cone crack penetration depth varies from 3 to 5 mm and apical angle from 53° to 40°. Electron backscatter diffraction (EBSD) mapping of the crack tip shows that fracturing initiates along a ∼40 μm wide process zone, comprising damage along overlapping en echelon high‐index crystallographic planes, shown by discrete bands of reduced electron backscatter pattern (EBSP) quality (band contrast). Coalescence of these surfaces results in a stepped fracture morphology. Monitoring of AE during indentation reveals that the elastic anisotropy of quartz has a significant effect on AE location and focal mechanisms. Ninety‐four AE events were recorded during indentation and show an increasing frequency with increasing load. They correspond to the development of subsidiary concentric cracks peripheral to the main cone crack. The strong and complex anisotropy in seismic velocity (∼28% Vp, ∼43% Vs with trigonal symmetry) resulted in inaccurate and high uncertainty in AE locations using Geiger location routine with an isotropic velocity model. This problem was overcome by using a relative (master event) location algorithm that only requires a priori knowledge of the velocity structure within the source volume. The AE location results correlate reasonably well to the extent of the observed cone crack. Decomposition of AE source mechanisms of the Geiger relocated events shows dominantly end‐member behavior between tensile and compressive vector dipole events, with some double‐couple‐dominated events and no purely tensile or compressive events. The same events located by the master event algorithm yield greater percentage of vector dipole components and no double‐couple events, indicating that AE source mechanism solutions can depend on AE location accuracy, and therefore, relocation routine that is utilized. Calculations show that the crystallographic anisotropy of quartz causes apparent deviation of the moment tensors away from double‐couple and pure tensile/compressive sources consistent with the observations. Preliminary modeling of calcite anisotropy shows a response distinct from quartz, indicating that the effects of anisotropy on interpreting AE are complex and require detailed further study.
The purpose of this ISRM Suggested Method is to describe a methodology for in situ acoustic emission monitoring of the rock mass fracturing processes occurring as a result of excavations for tunnels, ...large caverns in the fields of civil, rock slopes and mining engineering, etc. In this Suggested Method, the equipment that is required for an acoustic emission monitoring system is described; the procedures are outlined and illustrated, together with the methods for data acquisition and processing for improving the monitoring results. There is an explanation of the methods for presenting and interpreting the results, and recommendations are supported by several examples.
Introduction Meritocracy, a concept revered as the cornerstone of fairness and equal opportunity, is critically examined in the context of neurosurgery. This article challenges the notion that ...success in this demanding field is solely determined by individual abilities and effort. It reveals that factors such as background, gender, and socioeconomic status significantly influence one's career trajectory. By investigating how these systemic barriers impact admissions to neurosurgical training programs and professional advancement, the paper underscores the complexity of meritocracy in neurosurgery, suggesting that the meritocratic ideal is more nuanced and influenced by external variables than commonly believed. Results Certain universities deemed elite offer a curriculum divergent from that of their counterparts in low and middle-income countries. Students at these “elite” institutions gain exposure to new technologies and research incentives, which brings us to the realm of research. Remarkably, 75% of articles originating from developed nations account for just 25% of traumatic brain injury cases. This disparity highlights a significant research imbalance, and the common refrain underscores the need to bolster research capabilities in low-income countries. For neurosurgeons in the developing world, engaging in research often becomes a luxury due to multifaceted challenges. Financial barriers, including publication costs and paywalls for accessing articles, pose significant hurdles. Comparing salaries between countries underscores the glaring divide according to “Neurosurgeon Salary” in 2024. Neurosurgeons in the United States receive a median salary of $412,000 dollars per year, compared to $13,200 dollars in Latin America, as of June 2023. Given such incongruities, the prospect of even attending conferences or workshops abroad remains difficult for neurosurgeons from developing nations. Research isn't cast aside due to a lack of interest but due to resource limitations. The present landscape demands reconsideration. Conclusion We underscore the journey towards a more inclusive and equitable future in neurosurgery as not just a goal, but a dynamic process fuelled by resilience, collaboration, and a commitment to diversity. The narrative promotes a collective endeavour to dismantle barriers and embrace innovation, emphasizing the importance of mentorship, cross-institutional collaboration, and the amplification of underrepresented voices.
Microseismicity is extensively used to monitor induced damage accumulation and stability of underground structures. Classical location routines in this context can often not resolve the potential ...coalescence of the induced microcracks, since the location accuracy is on the order of magnitude of the largest fractures observed. Most of the uncertainty arises from the poor knowledge of the seismic velocity field. Master event relocation techniques can circumvent this problem and significantly improve the accuracy in hypocenter determination. We relocate events recorded during the excavation of the TSX tunnel at the Underground Research Laboratory (URL) and show that the resolution is enhanced by up to one order of magnitude. The relocated events locate closer to the excavation perimeter than the absolute locations, a result that corresponds with the observed damage. Additionally the relocated events define a clearer structure, with planes of alignment parallel to the tunnel perimeter.
Introduction: Lumbar foraminal stenosis (LFS) occurs primarily due to degenerative changes in older adults, affecting the spinal foramina and leading to nerve compression. Characterized by pain, ...numbness, and muscle weakness, LFS arises from structural changes in discs, joints, and ligaments, further complicated by factors like inflammation and spondylolisthesis. Diagnosis combines patient history, physical examination, and imaging, while management ranges from conservative treatment to surgical intervention, underscoring the need for a tailored approach. Materials and Methods: This multicenter study, conducted over six years at a tertiary hospital, analyzed the volumetric dimensions of lumbar foramina and their correlation with nerve structures in 500 patients without lumbar pathology. Utilizing high-resolution MRI with a standardized imaging protocol, eight experienced researchers independently reviewed the images for accurate measurements. The study emphasized quality control through the calibration of measurement tools, double data entry, validation checks, and comprehensive training for researchers. To ensure reliability, interobserver and intraobserver agreements were analyzed, with statistical significance determined by kappa statistics and the Student’s t-test. Efforts to minimize bias included blinding observers to patient information and employing broad inclusion criteria to mitigate referral and selection biases. The methodology and findings aim to enhance the understanding of normal lumbar foramina anatomy and its implications for diagnosing and treating lumbar conditions. Results: The study’s volumetric analysis of lumbar foramina in 500 patients showed a progressive increase in foraminal volume from the L1/L2 to the L5/S1 levels, with significant enlargement at L5/S1 indicating anatomical and biomechanical complexity in the lumbar spine. Lateral asymmetry suggested further exploration. High interobserver and intraobserver agreement levels (ICC values of 0.91 and 0.95, respectively) demonstrated the reliability and reproducibility of measurements. The patient cohort comprised 58% males and 42% females, highlighting a balanced gender distribution. These findings underscore the importance of understanding foraminal volume variations for lumbar spinal health and pathology. Conclusion: Our study significantly advances spinal research by quantifying lumbar foraminal volumes, revealing a clear increase from the L1/L2 to the L5/S1 levels, indicative of the spine’s adaptation to biomechanical stresses. This provides clinicians with a precise tool to differentiate between pathological narrowing and normal variations, enhancing the detection and treatment of lumbar foraminal stenosis. Despite limitations like its cross-sectional design, the strong agreement in measurements underscores the method’s reliability, encouraging future research to further explore these findings’ clinical implications.
Fruits and seeds are the major food source on earth. Both derive from the gynoecium and, therefore, it is crucial to understand the mechanisms that guide the development of this organ of angiosperm ...species. In Arabidopsis, the gynoecium is composed of two congenitally fused carpels, where two domains: medial and lateral, can be distinguished. The medial domain includes the carpel margin meristem (CMM) that is key for the production of the internal tissues involved in fertilization, such as septum, ovules, and transmitting tract. Interestingly, the medial domain shows a high cytokinin signaling output, in contrast to the lateral domain, where it is hardly detected. While it is known that cytokinin provides meristematic properties, understanding on the mechanisms that underlie the cytokinin signaling pattern in the young gynoecium is lacking. Moreover, in other tissues, the cytokinin pathway is often connected to the auxin pathway, but we also lack knowledge about these connections in the young gynoecium. Our results reveal that cytokinin signaling, that can provide meristematic properties required for CMM activity and growth, is enabled by the transcription factor SPATULA (SPT) in the medial domain. Meanwhile, cytokinin signaling is confined to the medial domain by the cytokinin response repressor ARABIDOPSIS HISTIDINE PHOSPHOTRANSFERASE 6 (AHP6), and perhaps by ARR16 (a type-A ARR) as well, both present in the lateral domains (presumptive valves) of the developing gynoecia. Moreover, SPT and cytokinin, probably together, promote the expression of the auxin biosynthetic gene TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1 (TAA1) and the gene encoding the auxin efflux transporter PIN-FORMED 3 (PIN3), likely creating auxin drainage important for gynoecium growth. This study provides novel insights in the spatiotemporal determination of the cytokinin signaling pattern and its connection to the auxin pathway in the young gynoecium.
Thymocyte selection-associated high-mobility group box (TOX) is a DNA-binding factor that is able to regulate transcription by modifying local chromatin structure and modulating the formation of ...multi-protein complexes. TOX has multiple roles in the development of the adaptive immune system including development of CD4 T cells, NK cells and lymph node organogenesis. However very few antibodies recognizing this molecule have been reported and no extensive study of the expression of TOX in reactive and neoplastic lymphoid tissue has been performed to date. In the present study, we have investigated TOX expression in normal and neoplastic lymphoid tissues using a novel rat monoclonal antibody that recognizes its target molecule in paraffin-embedded tissue sections. A large series of normal tissues and B- and T-cell lymphomas was studied, using whole sections and tissue microarrays. We found that the majority of precursor B/T lymphoblastic, follicular and diffuse large B-cell lymphomas, nodular lymphocyte-predominant Hodgkin lymphomas and angioimmunoblastic T-cell lymphomas strongly expressed the TOX protein. Burkitt and mantle cell lymphomas showed TOX expression in a small percentage of cases. TOX was not found in the majority of chronic lymphocytic leukemia, myelomas, marginal zone lymphomas and classical Hodgkin lymphomas. In conclusion, we describe for the first time the expression of TOX in normal and neoplastic lymphoid tissues. The co-expression of TOX and PD-1 identified in normal and neoplastic T cells is consistent with recent studies identifying TOX as a critical regulator of T-cell exhaustion and a potential immunotherapy target. Its differential expression may be of diagnostic relevance in the differential diagnosis of follicular lymphoma, the identification of the phenotype of diffuse large B-cell lymphoma and the recognition of peripheral T-cell lymphoma with a follicular helper T phenotype.
The progressive disseminated histoplasmosis (PDH) has been associated with severe disease and high risk of death among people living with HIV (PLWHIV). Therefore, the purpose of this multicenter, ...prospective, double-blinded study done in ten Mexican hospitals was to determine the diagnostic accuracy of detecting Histoplasma capsulatum antigen in urine using the IMMY ALPHA Histoplasma EIA kit (IAHE), clarus Histoplasma GM Enzyme Immunoassay (cHGEI IMMY) and MiraVista Histoplasma Urine Antigen LFA (MVHUALFA); as well as the Hcp100 and 1281-1283220SCAR nested PCRs in blood, bone-marrow, tissue biopsies and urine.
We included 415 PLWHIV older than 18 years of age with suspicion of PDH. Using as diagnostic standard recovery of H. capsulatum in blood, bone marrow or tissue cultures, or histopathological exam compatible, detected 108 patients (26%, 95%CI, 21.78-30.22) with proven-PDH. We analyzed 391 urine samples by the IAHE, cHGEI IMMY and MVHUALFA; the sensitivity/specificity values obtained were 67.3% (95% CI, 57.4-76.2) / 96.2% (95% CI, 93.2-98.0) for IAHE, 91.3% (95% CI, 84.2-96.0) / 90.9% (95% CI, 87.0-94.0) for cHGEI IMMY and 90.4% (95% CI, 83.0-95.3) / 92.3% (95% CI, 88.6-95.1) for MVHUALFA. The Hcp100 nested PCR was performed on 393, 343, 75 and 297, blood, bone marrow, tissue and urine samples respectively; the sensitivity/specificity values obtained were 62.9% (95%CI, 53.3-72.5)/ 89.5% (95%CI, 86.0-93.0), 65.9% (95%CI, 56.0-75.8)/ 89.0% (95%CI, 85.2-92.9), 62.1% (95%CI, 44.4-79.7)/ 82.6% (95%CI, 71.7-93.6) and 34.9% (95%CI, 24.8-46.2)/ 67.3% (95%CI, 60.6-73.5) respectively; and 1281-1283220SCAR nested PCR was performed on 392, 344, 75 and 291, respectively; the sensitivity/specificity values obtained were 65.3% (95% CI, 55.9-74.7)/ 58.8% (95%CI, 53.2-64.5), 70.8% (95%CI, 61.3-80.2)/ 52.9% (95%CI, 46.8-59.1), 71.4% (95%CI, 54.7-88.2)/ 40.4% (95%CI, 26.4-54.5) and 18.1% (95%CI, 10.5-28.1)/ 90.4% (95%CI, 85.5-94.0), respectively.
The cHGEI IMMY and MVHUALFA tests showed excellent performance for the diagnosis of PDH in PLWHIV. The integration of these tests in clinical laboratories will certainly impact on early diagnosis and treatment.
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