Dumbbell Shape Research Articles

Management of large Trigeminal Schwannoma: long-term oncologic and functional outcome from a multicentric retrospective cohort.

Trigeminal schwannoma (TS), though a rare and benign tumor, becomes a significant surgical challenge due to its intricate location. This study aims to detail the long-term functional outcomes and tumor control post-surgical resection. We analyzed a multicentric retrospective cohort of 39 patients operated on for a TS in five tertiary centers between January 1993 and July 2022. Six TS (15%) were in the middle fossa (type M), two (5%) in the posterior fossa (type P), and two (5%) were extracranial (type E). Twenty-nine (75%) were Dumbbell shape: Eighteen (47%) were MP type, seven (18%) were MPE type, and four (10%) were ME type. Fifth nerve symptoms were the foremost preoperative complaint: hypesthesia (51%), trigeminal neuralgia (36%), and paresthesia (30%). We report a favorable evolution course for 61% of preexisting deficits (half of patients with preoperative paresthesia and neuralgia improved while only 5% of preoperative hypesthesia improved). Postoperative hypesthesia was the most frequent de novo deficit 14 (74%) and resolved in solely half the cases. Various approaches were used according to tumor type. Gross total resection (GTR), Subtotal resection (STR), and partial resection (PR) were achieved in respectively 33% (N = 13), 10% (N = 4), and 56% (N = 22) of patients. The mean clinical and radiological FU was 63months (12 - 283months). GTR led to no sign of recurrence (mean FU: 60months - range: 12-283months). For STR or PR (67%): 23 (88%) were assigned to a Wait-&-rescan policy (WS group) which offered stability in 70% (N = 16). Three cases (8%) underwent a complementary GKS (GammaKnife) on the residual lesion (GK group) without tumor change. For large TS, the completeness of resection must consider the potential functional burden of surgery. With giant infiltrating lesions, a strategy of planned subtotal resection, complemented by radiosurgery, either complementary or uppon regrowth, may provide similar oncological outcomes.

9183 Pituitary Metastasis Of Lung Adenocarcinoma Presenting As Anterior Pituitary Dysfunction

Abstract Disclosure: O. faour: None. M. Kinaan: None. S.K. Suryanarayanan: None. Introduction: The pituitary should not be overlooked as a site for metastasis and can be the first presentation of neoplastic disease in some patients. Most common presenting symptoms: headache, ophthalmoplegia, visual field defect and Arginine Vasopressin Deficiency (AVP-D). We present a case of pituitary metastasis of lung adenocarcinoma presenting as anterior Pituitary dysfunction that also showed partial AVP-D unmasked after starting steroids. Case Description: A 63-year-old male with history of tobacco use, COPD, and hypertension presented with syncope. He reported a 30lbs weight loss within prior 2 months, low energy, increased thirst, and polyuria. Physical exam was significant for cachexia, normal visual field on confrontation, and vital signs of BP 100/61, HR 83, and Weighing 180 lbs. Since he had syncope, Cortisol checked was undetectable and Free T4 was low, He was started on hydrocortisone and levothyroxine. CTA chest revealed a right hilar mass measuring 2.7 x 3 cm. Endobronchial biopsy was consistent with lung adenocarcinoma. MRI of pituitary gland revealed solid hypointense lesion with glandular thickening and diffuse heterogeneity involving most of the pituitary gland measuring up to 16 mm. No cavernous sinus invasion. Pituitary infundibulum showed diffuse thickening and enhancement of the pituitary stalk throughout with Intact posterior pituitary bright spot. Labs showed low LH, cortisol, ACTH, GH, TSH, and ADH. Initially, the patient was able to maintain a euvolemic status through increased water intake; however, he was later found to have partial central AVP-D when steroids were introduced. He responded to the use of Desmopressin, developed hyponatremia after 3 doses. He was started on a combination of carboplatin/pemetrexed/pembrolizumab but had no response and was transferred to palliative care/hospice and passed away within 7months after diagnosis.Discussion:Pituitary metastasis is rare and most commonly occurs in lung and breast cancers. Unfortunately, they are associated with poor prognosis. MRI findings of loss of posterior pituitary bright spot, thickening of the stalk, and dumbbell shape can be helpful in distinguishing between primary pituitary tumors and metastases. PET-FDG scan has limited value. Pituitary metastasis commonly presents with posterior pituitary dysfunction due to direct blood supply. Unmasking or worsening of AVP-D can happen with steroid replacement in patients requiring initiation or intensification of Desmopressin therapy. Treatment involves combination of surgery, radiation therapy, and systemic treatment for the primary cancer which can improve symptoms only but does not improve mortality. Presentation: 6/1/2024

Dumbbell Shaped Bi-Paddled Pectoralis Major Myocutaneous Flap (PMMF) for Composite Commissural Defects: A Defect Driven Modification

Pectoralis major myocutaneous flap (PMMF) has been a workhorse in orofacial reconstruction. Although microvascular tissue transfer has gained popularity in major tertiary centres, several infrastructural factors limit its use in many facilities, particularly in developing countries with high caseloads. Numerous modifications have been made to the PMMF since its inception. Here, we present a novel technique for reconstructing composite commissural defects with PMMF by modifying the skin paddle design to a dumbbell shape. Both ends of the paddle are used to line intraoral and extraoral defects, while the constricted middle portion recreates the commissure. We report the outcomes of a cohort of seven patients treated at our institution, describing the modified PMMF design, harvesting, and in-setting techniques used in oral carcinoma cases involving the commissure. We have detailed the study outcomes for each patient, including the various complications related to the flap, donor, and recipient sites.

A general framework to optimize fracture parameters in tight gas reservoir of heterogeneous channel sand bodies

Optimizing fracture parameters can unlock the potential of tight gas reservoirs. Various frameworks have been proposed as efficient optimization tools. However, current frameworks are mostly aimed at regular rectangular oil or gas reservoirs. The effect of heterogenous channel sand bodies on fracture parameter optimization has not been discussed. Here, we proposed a general optimization framework. The first step is to establish a heterogeneous channel sand bodies model based on image processing and data interpolation methods. The second step is to couple optimization algorithm and reservoir simulator to optimize fracture parameters. Then the framework is applied to two actual wells in Shaximiao Formation in Sichuan Basin in China. Results show that, the effect of channel sand body on the fracture optimization cannot been ignored. The optimal fractures tend to be concentrated in areas with good physical properties and large control areas. The sand body boundary has a significant control effect on the fracture half-length. For both fracture length and conductivity, double dumbbell shape is better than uniform shape. Our general framework serves as an efficient tool to optimize fracture design in heterogeneous channel sand body, which plays a growing role in enhancing tight gas recovery.

Classification of DNA Mixtures by Nanoelectrokinetic Driftless Preconcentration

Nanofluidic phenomena, particularly Ion Concentration Polarization (ICP), have been actively utilized for advancing various research fields, including chemical analysis and biomedical diagnostics, over the past century. While ICP can be used as effective preconcentration techniques in bio-/chemical analysis, there are few studies to investigate the shape of preconcentration plug, especially perpendicular distribution of analyte in the preconcentration plug. Previously we have reported the theoretical analysis of the distribution so that the types of plug were categorized as dumbbell or plug shape. In this study, we further investigated the classification of real DNAs within micro-/nanofluidic devices by examining the preconcentration dynamics of different DNA types under diverse electrical conditions. Our investigation successfully distinguished distinct preconcentration profiles for Short DNA, Multi-short DNAs, and Equitable DNA with introducing the concept of the Radius of Gyration for Fluorescence (RGF). We provided a quantitative framework to analyze and differentiate preconcentration shapes with reasonable precision. These findings not only deepen our understanding of DNA preconcentration dynamics but also provide implications for genetic diagnostics. As a simpler and more accessible pre-test tool, our research could be utilized as the efficient genetic testing, particularly in diagnosing disorders characterized by variations in DNA length.

A Time-Domain Perspective on the Structural and Electronic Response in Epitaxial Ferroelectric Thin Films on Silicon.

This operando study of epitaxial ferroelectric Pb(Zr0.48Ti0.52)O3 capacitors on silicon substrates studies their structural response via synchrotron-based time-resolved X-ray diffraction during hysteresis-loop measurements in the 2-200 kHz range. At high frequencies, the polarization hysteresis loop is rounded and the classical butterfly-like strain hysteresis acquires a flat dumbbell shape. We explain these observations from a time-domain perspective: The polarization and structural motion within the unit cell are coupled to the strain by the piezoelectric effect and limited by domain wall velocity. The solution of this coupled oscillator system is derived experimentally from the simultaneously measured electronic and structural data. The driving stress σFE(t) is calculated as the product of the measured voltage U(t) and polarization P(t). Unlike the electrical variables, σFE(t) and η(t) of the ferroelectric oscillate at twice the frequency of the applied electrical field. We model the measured frequency-dependent phase shift between η(t) and σFE(t).

Refractive insensitive directional bend sensor based on specialty microstructure optical fiber with dumbbell shape core

With the development of information society, more and more special occasions are calling for a wide range of sensors with special properties. In this work, a refractive index insensitive directional bend sensor is proposed based on a specialty microstructure optical fiber with dumbbell shape core, which works as a dual core fiber (DCF). Firstly, this specialty microstructure optical fiber with dumbbell shape core has been fabricated with self-pressurised drawing technique. Then, it has been constructed as a Mach-Zehnder interferometer (MZI) sensor. Consequently, its bend sensing characteristics has been investigated from both theory and experiment. The response of the proposed sensor to the bending evidently displays the directional dependence. In the bending along x direction, the interference peak wavelength is almost insensitive to the curvature. But the transmission is sensitive, which almost obeys the exponential function. Correspondingly, in the bending along y direction the wavelength almost linearly varies with curvature, giving out an averaged sensitivity of 2.44 nm/m−1 in the curvature range of 0–3.79 m−1. But the peak transmission fluctuates without typical principle. In addition, the response of the proposed sensor to the refractive index variation has been checked. It is found that the peak wavelength is almost insensitive to the change of refractive index from 1.33 to 1.45, and the peak transmission fluctuates without clear principle. All these results demonstrate that the proposed sensor has great potential for future internet of things (IoT) applications.

Study on Temporal and Spatial Distribution of Landslides in the Upper Reaches of the Yellow River

The geological structure of the upper reaches of the Yellow River is complex, especially in the Sigouxia-Laganxia section. It has always been a high-incidence area of landslide disasters, which poses a threat to the safe operation of the upper reaches of the Yellow River. In this study, based on the high-precision remote sensing image data, the spatial distribution of each landslide was obtained by superimposing the remote sensing image and the 1:50,000 digital elevation model (DEM). Some typical landslides were selected for detailed field investigation and field verification. The results show that the remote sensing image characteristics of landslides in the upper reaches of the Yellow River are obvious. Through remote sensing interpretation and field investigation, a total of 508 landslides of various types were found, including 24 giant landslides. The spatial spreading patterns of landslides mainly include six types: dumb-bell shape, rectangle, saddle type, long arc shape, triangle, and side-by-side shape. The length and width of the landslide deposit are mainly concentrated at 550–1500 m and 600–1500 m, and the average elevation of the sliding body is mainly concentrated between 2000 and 2800 m. The average slope of the landslide is mainly distributed between 15–20°. Giant landslides are mainly distributed in the Jianzha basin area, surrounded by the Jishishan fault and the Lajishan fault in the West Qinling Mountains. The spatial distribution characteristics of giant landslides have obvious regional differences due to different factors such as lithologic differences and riverside erosion. The research results are of great significance for the early identification, prevention, and mitigation of landslide disasters in the upper reaches of the Yellow River.

Harnessing the power of multifunctional γ-Fe2O3@CuO nanocomposites: Effective extraction of heavy metals and bacterial pathogens from contaminated water

Waterborne diseases and carcinogenic effects associated with heavy metal poisoning have drawn considerable attentionto removing heavy metals from contaminated water and killing disease-causing bacteria. In this regard, γ-Fe2O3 nanoparticles (NPs) were synthesized by ion reduction method, while CuO NPsand γ-Fe2O3–CuO nanocomposites (NCs) by hydrothermal method. XRD, FTIR, FESEM, EDX and UV–visible spectroscopy were used for system characterization. The dumbbell shape of CuO NPs and spherical shape of γ-Fe2O3 NPs and γ-Fe2O3@CuO NCs were indicated via SEM analysis. The elemental composition and successful synthesis of γ-Fe2O3@CuONCs were confirmed by EDX results. The order for elemental composition: O > Cu > Fe showed the higher content ratio of Cu and O while Fe has the lowest content. The antibacterial activities against E. Coli and B. subtili were evaluated by Minimum Inhibitory Concentration (MIC) and Zone of Inhibition. γ-Fe2O3@CuO NCs showed excellent antibacterial performance as compared to γ-Fe2O3 NPs,CuO NPs, commercial Cu NPs and Cu salt. The drastic improvement in properties of γ-Fe2O3@CuO NCs resulted in better surface contact and extensive cell membranes rupture to eliminate bacterial pathogens present in wastewater Batch adsorption experiments were performed for selective removal of toxic Pb2+ ionsexisting in polluted water. The greatest adsorption capacity was determined to be 346 mg/g, and the highest removal percentage of 95 % was achieved at pH 4 in 60 min. Isotherm models and kinetic studies indicated that Pb2+ ions followed pseudo-second-order kinetics. The results obtained from batch adsorption experiment revealed γ-Fe2O3@CuO NCs as effective nanosorbent for quick elimination of toxic metal ions from industrial wastewater.

Tailoring Advanced CdS Anisotropy-Driven Charge Spatial Vectorial Separation and Migration via In Situ Dual Co-Catalyst Synergistic Layout.

Tailoring advanced anisotropy-driven efficient separation and migration of photogenerated carriers is a pivotal stride toward enhancing photocatalytic activity. Here, CdS-MoS2 binary photocatalysts are tailored into a dumbbell shape by leveraging the rod-shaped morphology of CdS and employing an in situ tip-induction strategy. To further enhance the photocatalytic activity, an in situ photo-deposition strategy is incorporated to cultivate MnOx particles on the dumbbell-shaped CdS-MoS2. The in situ deposition of MnOx effectively isolated the oxidatively active sites on the CdS surface, emphasizing the reductively active crystalline face of CdS, specifically the (002) face. Benefiting from its robust activity as a reduction active site, MoS2 adeptly captures photogenerated electrons, facilitating the reduction of H+ to produce hydrogen. The anisotropically driven separation of CdS photogenerated carriers markedly mitigates the Coulomb force or binding force of the photogenerated electrons, thus promoting a smoother migration toward the active site for photocatalytic hydrogen evolution. The hydrogen evolution rate of 35MnOx-CdS-MoS2-3 surpasses that of CdS by nearly an order of magnitude, achieving a quantum efficiency of 22.30% at 450nm. Under simulated solar irradiation, it attains a rate of 42.86mmol g-1 h-1. This work imparts valuable insights for the design of dual co-catalysts, anisotropy-driven spatial vectorial charge separation and migration, and the analysis of migration pathways of photogenerated carriers.

Formation mechanism of α particles in glycogen: Testing the budding hypothesis by Monte-Carlo simulation

Glycogen, a complex branched glucose polymer and a blood-sugar reservoir in animals, comprises small β particles joined together into composite α particles. In diabetic animals, α particles fragment more easily than those in healthy animals. Finding evidence for or against postulated mechanisms for α-particle formation is thus important for diabetes research. Insight into this is obtained here using Monte-Carlo simulations, including addition and loss of glucose monomer, branching and debranching, based on earlier simulations which were in acceptable agreement with experiment [Zhang et al., Int J Biol Macromolecules 2018, 116, 264]. One postulated mechanism for α-particle formation is “budding”: occasionally a glucan chain temporarily protrudes from the particle, and if its growing end is sufficiently far from its parent particle, it propagates to a new linked particle. We tested this by simulations in which an “artificial” bud (a chain extending well outside the average particle radius) is added to a glycogen molecule in a dynamic steady state, and the system allowed to evolve. In some simulations, the particle reached a new steady state having an irregular dumbbell shape: a rudimentary α particle. Thus ‘budding’ is a possible mechanism for α particles to form. If no simulations had shown this behaviour, it would have refuted the postulate.

Physics-based neural network as constitutive law for finite element analysis of sintering

In the sintering of advanced ceramics, a digital twin consisted of a finite element model can predict the final shape and microstructure of a sintered ceramic. However, to minimise uncertainties, it is essential to continually update the mechanical properties in the digital twin using data collected from the manufacturing process. One promising approach for achieving this is through artificial neural networks (ANN). This study introduces a machine learning strategy to update the constitutive behaviour of advanced ceramics in finite element analysis of sintering deformation. A major challenge in implementing machine learning in material processing is the huge amount of data required by the training and validation of an ANN, which are often unavailable or incomplete in a real manufacturing process. This study demonstrates that the data requirement can be reduced by employing a two-step training technique. Firstly, the ANN is trained using a nonlinear constitutive law, which describes a general relationship between the strain rates and stresses. Subsequently, the weights and biases of the ANN are transferred for the retraining using limited experimental data for an actual ceramic. It is shown that such approach can successfully capture the nonlinear constitutive behaviour of fine-grained alumina without demanding for large amount of experimental data. A case study is provided, highlighting the feasibility of implementing the ANN in a commercial finite element package, to replace the constitutive law and predict the shrinkage and distortion of a sintering part. In particular, the sintered dumb-bell shape part, simulated using the retrained ANN, showed grain size and relative density that markedly different from those using the nonlinear constitutive law. It is important to note that the proposed methodology is generic and can be used to create ANNs to replace constitutive laws in finite element analysis in digital twins for a wide range of other engineering processes.

Fast alternating fitting methods for trigonometric curves for large data sets

This paper discusses and develops new methods for fitting trigonometric curves, such as circles, ellipses, and dumbbells, to data points in the plane. Available methods for fitting circles or ellipses are very sensitive to outliers in the data, and are time consuming when the number of data points is large. The present paper focuses on curve fitting methods that are attractive to use when the number of data points is large. We propose a direct method for fitting circles, and two iterative methods for fitting ellipses and dumbbell curves based on trigonometric polynomials. These methods efficiently minimize the sum of the squared geometric distances between the given data points and the fitted curves. In particular, we are interested in detecting the general shape of an object such as a galaxy or a nebula. Certain nebulae, for instance, the one shown in the experiment section, have a dumbbell shape. Methods for fitting dumbbell curves have not been discussed in the literature. The methods developed are not very sensitive to errors in the data points. The use of random subsampling of the data points to speed up the computations also is discussed. The techniques developed in this paper can be applied to fitting other kinds of curves as well.

Etched stainless steel wire modified with conjugated microporous polymers-F6 for jacket-free stir bar sorptive extraction of benzoylureas in juice sample.

Benzoylurea (BU) insecticides have been widely used for pest control as third-generation insecticides. Considering that their residues in food may cause adverse effects on human health, the upper limits of BUs remaining in food have been set by the administration. Therefore, it is essential to develop a sensitive and efficient analytical method to determine the residues of BUs in food. Stir bar sorptive extraction (SBSE) is a novel sample preparation technique, and stainless steel wire (SSW) is an ideal substrate for an SBSE device. In this work, a novel SBSE device of SSW jacket-free stir bar with a dumbbell shape was designed and prepared. The conjugated microporous polymer CMP-F6, which possesses a porous structure, high hydrophobicity and rich fluorine-containing functional groups, was immobilized on the surface of SSW by the method of polyacrylonitrile glue adhesion. Compared with previous studies, which used SSW as a substrate, the method of etching partial SSW with hydrochloric acid, on the one hand, made the surface of SSW rough and easy to modify the extraction coating, and on the other hand, converted itself into a dumbbell-shaped structure, which is conducive to improving the extraction efficiency and stability of the SBSE device. The method of SBSE-HPLC-UV was established for determining five BUs. Owing to the hydrophobic interaction and F-F interaction between CMP-F6 and analytes, this method showed good extraction efficiency and had good linearity (R2 ≥ 0.9945) and high sensitivity (LODs in the range of 0.1-0.2 ng mL-1). It was used for the analysis of benzoylurea in an apple juice sample, and the recoveries were 74.3-117.9%.

Structure Analysis and Its Correlation with Mechanical Properties of Microcellular Polyamide Composites Reinforced with Glass Fibers

Thin-walled and thick-walled microcellular moldings were obtained by MuCell® technology with nitrogen as a supercritical fluid. 2 mm thick polyamide 6 (PA6) with 30% wt. glass fiber (GF) samples were cut from automotive industrial elements, while 4 mm, 6 mm, and 8.4 mm thick moldings of PA6.6 with 30% wt. GF were molded into a dumbbell shape. The internal structure was investigated by scanning electron microscopy (SEM) and X-ray computed microtomography (micro-CT) and compared by numerical simulations for microcellular moldings using Moldex3D® 2022 software. Young’s modulus, and tensile and impact strength were investigated. Weak mechanical properties of 2 mm thick samples and excellent results for thick-walled moldings were explained. SEM pictures, micro-CT, and simulation graphs revealed the tendency to decrease the cell size diameter together with increasing sample thickness from 2 mm up to 8.4 mm.

Microfluidic device-based synthesis of highly monodispersed dumbbell-shaped gold nanorods and their biocompatibility evaluation

Anisotropic gold nanomaterials have always fascinated the scientific community; however, controlling their synthesis to achieve desired properties and monodispersity is challenging in a conventional batch reactor. Here, we report the synthesis of highly monodispersed dumbbell-shaped gold nanorods (Ds-Au NRs) in a droplet microfluidic device. The device comprises a tapered T-junction for reagent droplet production, a winding structure to promote nucleation, and lengthy parallel microchannels to support the slow growth required for dumbbell shape morphology. After optimising the flow parameters and device geometry for uniform droplet production, the aspect ratio of Ds-Au NRs was tuned by controlling the total reagent flow rate, reagent flow rate ratio, and concentration of shaping reagent and reducing agent. Compared to batch counterparts, reaction time was reduced to one-fifth and revealed higher monodispersity. The cytotoxicity analysis showed that microfluidic synthesised Ds-Au NRs are non-toxic and have great potential for usage in biomedical applications.

Understanding the determinants of where and what kind of home accommodation to build

As homestays have developed rapidly, it is necessary to understand the factors affecting their density and type distribution at the micro scale. Based on the Internet data of home accommodation, the spatial distribution characteristics of homestays in Shenzhen are studied by the nearest neighbour analysis, and type distribution characteristics are analysed by NVivo. The impacts of factors are discussed through geographical detectors. We conclude that Shenzhen's homestays are multi-centre agglomeration and development in space with the flat floor as the main house structure and the modern style as the main decoration style. The spatial distribution is mainly affected by social and economic factors such as the density of bus stations and subways. The density and diversity of the homestays is high with the nearest and farthest distance to the railway station and the popular tourist destination beach while low with the mediate distance, featured with dumbbell shape.

Nonclassical and Classical Crystallization: The Formation of Spindle-Shaped CaCO3 Covered with Abundant Nanoscale Rhombic Calcite Subunits

As an essential inorganic material, calcium carbonate (CaCO3) is one of the most abundant minerals in nature, whose preparation by the carbonation of calcium hydroxide [Ca(OH)2] suspension involves complex physical and chemical processes due to the presence of gas–solid–liquid phases. It is challenging to accurately predict the final morphology of CaCO3. In this paper, a novel spindle-shaped CaCO3 covered with a mass of nanoscale rhombic calcite subunits was prepared via the carbonation method. This structure was mainly formed by the aggregation of nanoparticles in the pre-reaction stage and turned into a classical ion–ion growth process at the stage of the late reaction. During the pre-reaction period, solid Ca(OH)2 kept the solution supersaturated and made the aggregation of nanoparticles dominate and assemble to form the nanochains of CaCO3. Subsequently, the aggregation of nanochains formed a dumbbell shape, which was accompanied by the recrystallization of nanoparticles inside aggregates to create an ordered single-crystal spindle structure. Finally, the concentration of Ca(OH)2 decreased, and a layer of nanoscale rhombic calcite subunits grew on the surface of spindle CaCO3. This work will provide new insights into the industrial preparation of CaCO3 with controlled morphology and contribute to understanding the biomineralization of aggregation-based growth in aqueous solutions.

Experimental Study of the Mechanical Properties of a Flexible Grid Filling Body

The fill mining method has become more widely used due to its advantages of a high resource recovery rate, reliability and safety, and reduced surface tailings storage. However, the mechanical properties of the cemented fillings in fill mining are similar to those of ultra-low strength plain concrete, and there are problems such as high brittleness, low bending and tensile strength, and sudden failure. Using a flexible grid as reinforcement material, uniaxial compression, tensile, and shear tests of a flexible grid filling body were carried out, and the results were compared with the mechanical properties of the filling body without the flexible grid. We drew the following main conclusions: the uniaxial compressive strength of the flexible grid filling body gradually increased with the decrease in the grid spacing (the increase in the grid density); the grid dimension had little effect on the uniaxial compressive strength of the flexible grid filling body. The uniaxial tensile strength and shear strength of the flexible grid filling body increased with the increase in the grid dimension; and they first increased and then decreased with the increase in the grid spacing, and there was an optimal grid spacing. From the perspective of the macroscopic failure mode, the flexible grid filling body specimen after the uniaxial compression test had a conjugate shear failure, forming a “dumbbell shape” with two large ends and a small middle. After the uniaxial tensile test, the macroscopic failure mode of the specimen was tensile failure. After the shear test, the macroscopic failure mode of the specimen was shear slip failure. It is proposed that the tensile strength, shear strength, cohesion, and internal friction angle strengthening coefficients of the flexible grid filling body with different dimensions and spacing are higher than the elastic modulus strengthening coefficients. The experimental results can provide a certain reference and guidance for mine filling.

Primary cervical meningeal melanocytoma with a dumbbell shape: Case report and review of the literature.

Meningeal melanocytoma is a rare benign pigmented tumor originat from leptomeningeal melanocytes. Here, we report the case of a female who presented with numbness and weakness of the limbs for approximately 6 months. We report the case of a 60-year-old Chinese female who presented with numbness and weakness of the limbs for approximately 6 months. computed tomography (CT) and magnetic resonance imaging (MRI) revealed a dumbbell-shaped tumor inside and outside the cervical (C) spinal canal. The patient was using CT and MRI. Subsequently, the patient underwent surgery, and low-grade melanocytoma was diagnosed pathologically. Subsequently, the patient underwent a surgery, and the tumor was completely removed. The tumor did not recur after 6 months. This case suggested 2 "take-away" lessons: first, spinal meningeal melanocytomas may be dumbbell-shaped; and second, melanocytoma could appear as hyperintense, isointense, or hypointense on T2-weighted MRI.