The partial upward migration of the laryngeal motor cortex: A window to the human brain evolution.

The pioneer cortical electrical stimulation studies of the last century did not explicitly mark the location of the human laryngeal motor cortex (LMC), but only the "vocalization area" in the lower half of the lateral motor cortex. In the final years of 2010́s, neuroimaging studies did demonstrate two human cortical laryngeal representations, located at the opposing ends of the orofacial motor zone, therefore termed dorsal (LMCd) and ventral laryngeal motor cortex (LMCv). Since then, there has been a continuing debate regarding the origin, function and evolutionary significance of these areas. The "local duplication model" posits that the LMCd evolved by a duplication of an adjacent region of the motor cortex. The "duplication and migration model" assumes that the dorsal LMCd arose by a duplication of motor regions related to vocalization, such as the ancestry LMC, followed by a migration into the orofacial region of the motor cortex. This paper reviews the basic arguments of these viewpoints and suggests a new explanation, declaring that the LMCd in man is rather induced through the division of the unitary LMC in nonhuman primates, upward shift and relocation of its motor part due to the disproportional growth of the head, face, mouth, lips, and tongue motor areas in the ventral part of the human motor homunculus. This explanation may be called "expansion-division and relocation model".

Empirical approaches for rock burst prediction: A comprehensive review and application to the new level of El Teniente Mine, Chile.

Rockburst phenomena pose significant challenges in the mining industry, particularly with increased underground activities at greater depths. These sudden failures not only jeopardize personnel safety but also impact mining investments. Consequently, it becomes crucial to assess the reliability and effectiveness of empirical methods employed for predicting rock burst occurrences and their severity, an ongoing subject of debate within the scientific community. This research presents a comprehensive review of empirical approaches for rock burst prediction. Subsequently, these approaches are applied to predict rock burst occurrences and its intensity within sections of a tunnel at the new level of El Teniente mine in Chile. Most of these methods rely on single-factor criteria to predict the likelihood and severity of rock bursts. However, inconsistencies are observed in the results obtained from these approaches in numerous cases. This discrepancy highlights the influence of various input parameters on rock burst estimations and emphasizes that single-index criteria may not encompass all the pertinent factors that contribute to this phenomenon. Consequently, such criteria may inadequately estimate or reflect the probability of rock burst occurrences. Given the multifaceted nature of rock burst phenomena, which depend on multiple factors, it becomes imperative to explore new approaches that consider a broader range of influencing factors, thereby yielding more realistic results. Hence, continued research is essential to develop new methods that address this issue comprehensively and ensure the safety of the mining industry.

A look at the performance of barrel and wedge assembly in cable bolts applications.

Pretensioning is one of the most common practices in cable bolting. A barrel and wedge is typically used in the free end of the cable to hold the pretension load. This study investigates the performance of barrel and wedge in cable bolt large-scale laboratory pull out tests. Twenty-five experiments have been completed containing various barrel and wedge and cable sizes under different loading conditions, namely monotonic and cyclic. The results indicated barrel and wedges undergo constant displacement throughout the experiment. The cyclic tests suggest that the barrel and wedge assembly displacement are almost entirely non-reversible. Two distinct behaviours, namely exponential and deflection point based, were observed. The study concludes that barrel and wedge assemblies can significantly influence the performance of cable bolts under axial load.

Control effect of coal mining solid-waste backfill for ground surface movement in slice mining: a case study of the Nantun Coal Mine.

Management of solid waste and protecting the ecological balance of the region are key challenges that the coal mining industry has to face. This study evaluated the effect of solid waste backfilling mining on the overlying strata movement and surface deformation variation pattern in slice mining. The mechanical characteristics of different cemented paste backfills (CPB) were compared. The CPB specimens were made of coal gangue and cement with or without the addition of fly ash. The experiments showed that the mechanical strength of the CPBs made of coal gangue and cement increased dramatically. A numerical simulation was then performed to analyze the variation patterns of the overlying strata displacement and surrounding rock stress distribution before and after filling the 3lower and 3upper coal seams with CPB. The CPBs reduced the movement of the surface by 95.1% and 95% during the mining of the 3lower and 3upper coal seams, respectively. Finally, we used a mining-induced subsidence prediction and analysis system to predict the influence of the 3lower and 3upper coal seams on the ground surface subsidence. It was found that the ground surface subsidence induced by CPB mining was 1/20 that of the cumulative ground surface subsidence caused by caving mining. CPB mining could effectively control the ground surface subsidence caused by multi-slice mining of the thick coal seam, offering protection for buildings above the ground. Our research provides theoretical and technical support for coal mining under buildings subjected to similar conditions.

Preliminary report of Iranian Registry of Alzheimer's disease in Tehran province: A cross-sectional study in Iran.

Background and Aims: Alzheimer's disease (AD) is the main cause of dementia and over the 55 million people live with dementia worldwide. We aimed to establish the first database called the Iranian Alzheimer's Disease Registry to create a powerful source for future research in the country. In this report, the design and early results of the Iranian Alzheimer's Disease Registry will be described. Methods: We performed this multicenter investigation and patients' data including age, sex, educational level, disease status, Mini-Mental State Examination (MMSE), and Geriatric Depression Scale (GDS) from 2018 to 2021 were collected, registered, and analyzed by GraphPad Prism software. Results: Totally 200 AD patients were registered in our database. 107 (54%) were women and age of 147 (74%) were over 65. The mean age for men and women was 76.20 ± 8.29 and 76.40 ± 8.83 years, respectively. 132 (66%) were married and 64 (32%) were illiterate. Also, 94 (47%) were in the moderate stage of disease, and 150 (75%) lived at home together with their families. The most frequent neurological comorbidity was psychosis (n = 72, 36%), while hypertension was the most common non-neurological comorbidity (n = 104, 52%). The GDS score of women in the mild stage (5.23 ± 2.9 vs. 6.9 ± 2.6, p = 0.005) and moderate stage (5.36 ± 2.4 vs. 8.21 ± 2.06, p = <0.001) of the disease was significantly greater than men. In univariate analysis, MMSC score was remarkably associated with stroke (ß = -2.25, p = 0.03), psychosis (ß = -2.18, p = 0.009), diabetes (ß = 3.6, p = <0.001), and hypercholesteremia (ß = 1.67, p = 0.05). Also, the MMSE score showed a notable relationship with stroke (ß = -2.13, p = 0.05) and diabetes (ß = 3.26, p = <0.001) in multivariate analysis. Conclusion: Iranian Alzheimer's Disease Registry can provide epidemiological and clinical data to use for purposes such as enhancing the current AD management in clinical centers, filling the gaps in preventative care, and establishing effective monitoring and cure for the disease.

Improved Shear Strength Performance of Compacted Rubberized Clays Treated with Sodium Alginate Biopolymer.

This study examines the potential use of sodium alginate (SA) biopolymer as an environmentally sustainable agent for the stabilization of rubberized soil blends prepared using a high plasticity clay soil and tire-derived ground rubber (GR). The experimental program consisted of uniaxial compression and scanning electron microscopy (SEM) tests; the former was performed on three soil-GR blends (with GR-to-soil mass ratios of 0%, 5% and 10%) compacted (and cured for 1, 4, 7 and 14 d) employing distilled water and three SA solutions-prepared at SA-to-water (mass-to-volume) dosage ratios of 5, 10 and 15 g/L-as the compaction liquid. For any given GR content, the greater the SA dosage and/or the longer the curing duration, the higher the uniaxial compressive strength (UCS), with only minor added benefits beyond seven days of curing. This behaviour was attributed to the formation and propagation of so-called "cationic bridges" (developed as a result of a "Ca2+/Mg2+ ⟷ Na+ cation exchange/substitution" process among the clay and SA components) between adjacent clay surfaces over time, inducing flocculation of the clay particles. This clay amending mechanism was further verified by means of representative SEM images. Finally, the addition of (and content increase in) GR-which translates to partially replacing the soil clay content with GR particles and hence reducing the number of available attraction sites for the SA molecules to form additional cationic bridges-was found to moderately offset the efficiency of SA treatment.

Strength Development and Strain Localization Behavior of Cemented Paste Backfills Using Portland Cement and Fly Ash.

This study examines the combined performance of Portland cement (PC), the binder, and fly ash (FA), the additive, towards improving the mechanical performance of the South Australian copper-gold underground mine cemented paste backfill (CPB) system. A series of unconfined compressive strength (UCS) tests were carried out on various mix designs to evaluate the effects of binder and/or additive contents, as well as curing time, on the CPB's strength, stiffness and toughness. Moreover, the failure patterns of the tested samples were investigated by means of the three-dimensional digital image correlation (DIC) technique. Making use of several virtual extensometers, the state of axial and lateral strain localization was also investigated in the pre- and post-peak regimes. The greater the PC content and/or the longer the curing period, the higher the developed strength, stiffness and toughness. The use of FA alongside PC led to further strength and stiffness improvements by way of inducing secondary pozzolanic reactions. Common strength criteria for CPBs were considered to assess the applicability of the tested mix designs; with regards to stope stability, 4% PC + 3% FA was found to satisfy the minimum 700 kPa threshold, and thus was deemed as the optimum choice. As opposed to external measurement devices, the DIC technique was found to provide strain measurements free from bedding errors. The developed field of axial and lateral strains indicated that strain localization initiates in the pre-peak regime at around 80% of the UCS. The greater the PC (or PC + FA) content, and more importantly the longer the curing period, the closer the axial stress level required to initiate localization to the UCS, thus emulating the failure mechanism of quasi-brittle materials such as rock and concrete. Finally, with an increase in curing time, the difference between strain values at the localized and non-localized zones became less significant in the pre-peak regime and more pronounced in the post-peak regime.

Engineering Reactive Clay Systems by Ground Rubber Replacement and Polyacrylamide Treatment.

This study investigates the combined performance of ground rubber (GR), the additive, and polyacrylamide (PAM), the binder, as a sustainable solution towards ameliorating the inferior geotechnical attributes of an expansive clay. The first phase of the experimental program examined the effects of PAM concentration on the soil's mechanical properties-consistency, sediment volume attributes, compactability, unconfined compressive strength (UCS), reactivity and microstructure features. The second phase investigated the effects of GR content, with and without the optimum PAM concentration. An increase in PAM beyond 0.2 g/L, the identified optimum concentration, caused the excess PAM to act as a lubricant rather than a flocculant. This feature facilitated reduced overall resistance to sliding of soil particles relative to each other, thereby adversely influencing the improvement in stress-strain-strength response achieved for ≤0.2 g/L PAM. This transitional mechanism was further verified by the consistency limits and sediment volume properties, both of which exhibited only minor variations beyond 0.2 g/L PAM. The greater the GR content, the higher the mobilized UCS up to 10% GR, beyond which the dominant GR-to-GR interaction (i.e., rubber-clustering) adversely influenced the stress-strain-strength response. Reduction in the soil's swell-shrink capacity, however, was consistently in favor of higher GR contents. Addition of PAM to the GR-blended samples amended the soil aggregate-GR connection interface, thereby achieving further improvements in the soil's UCS and volume change behaviors. A maximum GR content of 20%, paired with 0.2 g/L PAM, managed to satisfy a major decrease in the swell-shrink capacity while improving the strength-related features, and thus was deemed as the optimum choice.