bluuebunny/crossref_metadata_2025 huggingface dataset:
On-Line Evaluation of Drill Conditions for Operational Safety and Product Quality
Authors: Liu Tien-I , Lee Chongchan
Published: January 2022

In order to achieve safety, quality, and productivity in the drilling operation, a 11 × 10 × 1 neural network has been used online to classify the drill conditions into three categories : safe, caution, and danger. The inputs to the neural network includes drill size, feedrate, spindle speed, and features which were extracted from thrust and torque measurements during drilling experiments. The output of this neural network indicates the drill states. The on-line drill condition evaluation system can reach a success rate of over 95%. Furthermore, the one misclassification during on-line tests was a one-step ahead prealarm which is acceptable from an operational safety and product quality viewpoint. In other words, the developed system has extremely high reliability. In addition, the developed on-line detection system is very robust and can be used in very complex manufacturing environments.
A Simplified Method for Fixturing Aircraft Sheet Metal Parts During Post-Forming Operations
Authors: Walczyk Daniel F. , Raju Vinay , Miller Ron
Published: January 2022

Based on a survey of small- to medium-sized companies that supply sheet metal parts to the major aircraft manufacturers, there is a need for a more simplified, flexible and inexpensive method to design, fabricate and register part fixtures used for CNC post forming operations (e.g., trimming, drilling). Consequently, a method has been developed that satisfies these identified needs by customizing several existing part fixturing techniques to the aircraft manufacturing environment. Fabrication of the fixture is based on casting some material (e.g., polyurethane) in a CNC-machined mold of the part’s inside mold line and registration points, and then imbedding a simple support structure into the semi-cured, cast material. Generation of the “working” NC code is based on transforming a “master” NC code created from the original CAD model of the part to the new position and orientation of the actual fixture mounted in the CNC workbed. Little precision is required in either the fixture fabrication or registering. Practical implementation of this simplified method and an actual case study are discussed.
Fatigue Life Prediction of an Orthotropic 6061-Aluminum Under Proportional and Nonproportional Loading
Authors: Nayeb-Hashemi H. , Lin H.
Published: January 2022

Strain controlled low cycle fatigue tests are conducted on an anisotropic A1-6061-T6 rod following two non-proportional loading paths. Cyclic stress responses and fatigue lives are obtained and compared with those obtained from proportional loading paths. No additional non-proportional hardening is observed for the aluminum alloy. This is explained through the dislocation structure of the material. Anisotropic constitutive relations and fatigue life prediction models are further evaluated with the data of non-proportional loading paths. The constitutive relations and the anisotropic shear cracking model provide good predictions for the data of non-proportional loadings.
A MEMS Structure for Measuring the Fracture Strength of Thin Films
Authors: Johnson George C. , Jones Peter T. , Howe Roger T. , Au Michael
Published: January 2022

A surface micromachined structure for measuring the fracture strength of thin films used in MEMS has been developed [1.2]. The test structure consists of a rigid central shuttle which is suspended above the substrate by folded flexures. Extending from the shuttle are six cantilever beams of varying lengths. As the shuttle is pushed by an off-chip probe, the beams hit contact pads, which are attached to the substrate, and bend until they break. A vernier gauge inside the central shuttle allows measurement of the displacement to within 0.2μm. Optical micrographs of the fracture test structure and of a single bending beam are shown in Figure 1.
In-Situ Test Structures for Metrological and Mechanical Characterization of MEMS
Authors: Gupta Raj K.
Published: January 2022

Separating geometrical dependence from extracted mechanical stiffness parameters to obtain fundamental mechanical properties, such as the Young’s Modulus E and the internal (residual) stress σ within 10%, is difficult. Mechanical stiffness, obtained from an intermediate measured quantity, generally depends on high powers of structural geometry, but only linearly with mechanical property. For example, the maximum deflection of a uniformly loaded beam under linear-elastic conditions is proportional to L4 and 1/t3, where L is the beam length and t is the thickness, but is only linearly proportional to E. Secondly, geometric measurements to sub-micron precision as required for microelectromechanical systems (MEMS) require error-free techniques and metrological calibration standards. In this talk, methods for error-reduction, using techniques for detecting errors in measured geometry and a proposed method for in-situ wafer-level electrical measurement of geometry, are presented.
Asymptotic Crack-Tip Fields in an Anisotropic Plate Subjected to Bending Moments and Transverse Shear Loads
Authors: Yuan F. G. , Yang S.
Published: January 2022

Asymptotic crack-tip fields in an anisotropic plate under bending moments and transverse shear loads including the effect of transverse shear deformation is presented. Utilizing the Reissner variational principle, the equilibrium equations and stress resultant-displacement relations are obtained. Assuming the displacement and stress resultant are in a separation of variable form, it is found that the equations governing crack-tip fields of an anisotropic plate bending are analogous to those governing generalized plane deformation of a composite. Thus the Stroh formalism can be used to characterize the crack-tip fields of the anisotropic plate and the energy release rate can be expressed in a real form in terms of stress intensity factors. The degenerated case of isotropic plates is also presented. Finally, the coefficients of the asymptotic expansion can be obtained from the J-integral method and Betti’s reciprocal theorem together with the auxiliary fields.
A Novel Compatibility/ Equilibrium Based Iterative Post-Processing Approach for Axisymmetric Brittle Matrix Composites
Authors: Chaudhuri R. A. , Pagano N. J. , Tandon G. P. , Khan A. H.
Published: January 2022

A semi-analytical iterative approach for enhancing the existing two-dimensional quasi-continuous axisymmetric stress field for a brittle matrix micro-composite (e.g., a single fiber surrounded by a concentric matrix cylinder), is presented. The existing solution due to Pagano employs Reissner’s variational theorem in conjunction with an equilibrium stress field in which the radial (r-) dependence is assumed a priori.

In the present approach, the stress distribution in the radial direction obtained from the afore-cited variational model is improved a posteriori through an iterative approach that involves successive substitution of the previously computed strains (or stresses) into the equations of compatibility and equilibrium. The equations of compatibility are selected such that they form Euler equations corresponding to an appropriate variational principle, such as the principle of minimum complementary potential energy, etc.

The boundary/interface conditions at r = constant and z = constant surfaces/interfaces are satisfied in the pointwise sense. The expressions for the improved axisymmetric displacement and stress fields are derived using the symbolic language, MAPLE. An illustrative thermal stress problem is currently being solved, and will be used to compare with the existing variational solution.
Influence of Multiple Fiber Breaks on Stresses in a Fiber Composite With a Creeping Matrix
Authors: Beyerlein Irene J.
Published: January 2022

In this work, the influence of pre-existing fiber breaks on the local creep response of a planar unidirectional fiber composite under steady axial tension is investigated. Shear deformation of the Newtonian viscous matrix material or interface is assumed to dominate the creep response and result in time and temperature induced fiber failures. The recently developed computational mechanics technique, called viscous break interaction (VBI), is used to compute the time-dependent stress and strain redistributions in the fibers and matrix in response to large numbers of transversely aligned and staggered fiber breaks. In VBI, the key influence function in response to one fiber break is built on shear-lag theory, and when employing weighted superposition concepts to this function, the stress fields around multiple breaks is then calculated. The results uncover distinctions in the stress redistribution between large numbers of aligned breaks, e. g. transverse cracks and a finite and infinite periodic row of short cracks, versus a large process zone of staggered (misaligned) breaks. The results also show how both the time growing interactions and spatial arrangement and size of several close breaks influence local matrix creep rate, fiber tensile stress redistribution, and macroscopically, the timescales of multiple creep stages in overall composite strain. In the present application of the VBI technique, the composite model is representative of polymer matrix composites and also ceramic composites with a viscous secondary phase at elevated temperatures. For these systems, the model assumes the reinforcement is the primary load bearing component with time-independent, elastic properties and has a much higher volume fraction than that of the matrix. These studies on the time evolution of local stress are important for modeling the statistical evolution of process zone or crack-tip failure mechanisms in time.
Damage Mechanics for Hybrid Laminates
Authors: Whitcomb John , Noh Jae , Srirengan Kanthikannan
Published: January 2022

Damage in composite materials accumulates in a diffuse manner. Accounting for this damage in a progressive failure analysis requires an accurate measure of the degraded stiffness coefficients. This paper describes micromechanics models for predicting the effect of distributed cracks on the engineering properties (extensional and shear moduli, Poisson’s ratios, and thermal expansion coefficients). The configuration is shown schematically in Figure 1. The unit cell consists of three laminae: a cracked central lamina and two adjacent laminae. The adjacent laminae may or may not be damaged.

The effective properties of a cracked lamina are affected by the presence of the adjacent laminae. However, in an earlier paper by the authors (Reference. 1), it was shown that the effective properties of a cracked lamina normalized by their original values were quite insensitive to the adjacent lamina orientation and even the material system of the laminae group. This is illustrated in Figure 2. The results in Reference 1 were for a single cracked lamina, the adjacent lamina had the same orientation, and all three laminae had the same undamaged unidirectional properties. Also, in calculating the effective engineering moduli, shear-extension coupling terms were ignored. The current effort builds on the results in Reference 1. This paper considers hybrid laminates, adjacent plies with different orientations, damage in single and multiple laminae, a wider range of material systems, and thermal expansion coefficients. Quantitative measures are presented for the errors introduced when shear-extension coupling terms are ignored. Reference 1 used fully three-dimensional finite element models. This paper discusses the use of much more efficient quasi-3D models.
An Approach for Thermoviscoelastic Micro-Analysis for Woven Fabric Laminates
Authors: Chung Peter W. , Tamma Kumar K.
Published: January 2022

Structures containing micromechanical details is an active area of interest in the analysis of composite materials. The present investigation proposes a method for studying the thermorheological-viscoelastic problem associated with manufacturing and post-analysis of woven fabric laminates. The homogenization approach is employed to resolve the multi-scale issue. A general purpose 3-D finite element code has been developed containing features for heterogeneous thermoviscoelastic constituents exhibiting thermorheological behavior. Material nonlinearities via temperature dependent properties with instantaneous memory are considered and thus, allow for prediction of curing and cool-down residual stresses during manufacture. Test examples and comparisons with experimental observations are also presented.
Nonlinear Dynamic Snap-Through Buckling of Composite Laminated Spherical Shells
Authors: Yiqian Yang , Duan Zhang , Hongye Zhou , Hezhong Ma , Tsunkuei Wang
Published: January 2022

In this paper, a general, strain-consistent, third-order displacement field of shells is proposed. On this basis, the nonlinear theory of composite laminated shells including third-order transverse shear deformation and rotary inertia is developed. Hamilton’s variational principle is used to derive the nonlinear static and dynamic governing differential equations and the corresponding boundary conditions of composite laminated anisotropic general shells under the orthogonal curvilinear coordinates. And the form of spherical shells is degenerated. The model accounts for the cubic variations of the in-plane displacements through the thickness (thus, does not require any shear correction coefficients), stretching of transverse normals, the von karman nonlinear strain-displacement relations, initial geometric imperfection, rotary inertia, elastic foundations and viscous damping in order to simulate the real structures. The corresponding constitutive equations of composite laminated shells are derived. This paper uses the global orthogonal interior collocation method in space domain and the unconditionally stable Newmark-Beta and Houbolt numerical integration schemes in time domain to comprehensively investigate dynamic axisymmetric behavior of laminated cylindrically orthotropic composite shallow spherical shells subjected to suddenly applied loads. The sufficient condition for dynamic buckling, from the energy transfer consideration, is defined as the smallest load for which an unbounded motion is initiated at one generalized displacement, and the pressure corresponding to a sudden jump in the maximum volume change in the time history of the shell structure is taken as dynamic buckling pressure herein. For the sake of comparison, the results of first-order transverse shear and classical shell theories are presented in this paper. Results of detailed parametric imperfection, the total number of layers, lamination schemes, viscous damping, loading type and loading duration, the loaded area, loading rates, Winkler-Pasternak elastic foundations, opening semi-angle of circular hole, aritifical viscosity of difference scheme, boundary conditions, rotary inertia, transverse shear deformation, h/R (thickness/radius ratio of shells) and dynamic buckling criterion on the buckling loads. Previously the researches on shallow spherical shells were based on shallow shell assumptions. But in this paper, these assumptions are abandoned, thus the theoretical model can be used to study shallow spherical shells, as well as hemi-spherical shells and complete spherical shells. The semi-analytical solutions offered by this paper will provide bench-mark numerical results to test the accuracy of numerical methods. This paper clears up the confused ideas about the different effects of transverse shear deformation on the shallow and deep spherical shells in references.
Moiré Interferometry Measurements of Interlaminar Deformation at an Open Hole in Laminated Composite Materials
Authors: Mollenhauer David , Post Daniel , Reifsnider Kenneth
Published: January 2022

The deformation on cylindrical surfaces of holes in tensile-loaded laminated composite specimens was measured using new moiré interferometry techniques. Two composite tensile specimens, fabricated from IM7/5250-4 pre-preg with ply layups of [0°4/90°4]3s and [+30°2/-30°2/90°4]3s, were examined using the newly developed moiré interferometry techniques. Circumferential and thickness direction displacement fringe patterns (each 3° wide) were assembled into 90°-wide mosaics around the hole periphery for both composite specimens. Distributions of strain were calculated with high confidence on a sub-ply basis at select angular locations. Measured strain behavior was complex and displayed ply-by-ply treands. Large ply-related variations in the circumferential strain were observed at certain angular locations around the periphery of the holes in both composites. Extremely large ply-by-ply variations of the shear strain were also documented in both composites. Peak values of shear strain approached 30 times the applied far-field axial strain. Post-loaded viscoelastic shearing strains were recorded that were associated with the regions of large load-induced shearing strains. Large ply-group related variations in the thickness direction strain were observed in the [+30°2/-30°2/90°4]3s specimen. An important large-scale trend was observed where the thickness direction strain tended to be more tensile near the outside faces of the laminate than near the mid-ply region. The measured strains were compared with the three-dimensional analysis technique known as Spline Variational Elastic Laminate Technology (SVELT), resulting in a very close match and corroborating the usefulness of SVELT.
Influence of Adhesive Reinforcement on the Mode I Fracture Toughness of a Bonded Joint
Authors: Forte M. S. , Whitney J. M. , Schoeppner G. A.
Published: January 2022

The influence of adhesive reinforcement on the fracture toughness is investigated with a computer model based on a variational theorem that has been shown to accurately predict stress fields and energy release rates for cracked laminates. An axisymmetric damage plane strain model was developed and used to determine the Mode I energy release rate for midplane cracking in aluminum bonded specimens with varying amounts adhesive reinforcement. The calculated energy release rates are compared to closed form analyses in a systematic test program.
An Investigation of the Effects of Layer Thickness on the Fracture Behavior of Layered NiAl/V Composites
Authors: Li M. , Wang R. , Katsube N. , Soboyejo W. O.
Published: January 2022

The effect of vanadium layer thickness (100, 200 and 400 μm) on the resistance curve behavior of NiAl/V microlaminates are examined in this paper. The fracture resistance of the NiAl/V microlaminates is shown to increase with increasing layer thickness. The improved fracture toughness (compared to that of unreinforced NiAl) is associated with crack bridging and the interactions of cracks with vanadium layers. The re-initiation of cracks in adjacent NiAl layers is modeled using finite element methods. The re-initiation is shown to occur as a result of strain concentrations at the interface between the adjacent NiAl layers and vanadium layers. The initial deviation of the re-initiated cracks from the pure mode I direction is shown to occur in the direction of maximum shear strain. Toughening due to crack bridging is also modeled using finite element models of the observed crack/microstructure profiles.
Behavior of Polymeric Composites Exposed to a Heat Flux Simulating Fire
Authors: Potocki Mark L. , Tuttle Mark E. , Mescher Ann M.
Published: January 2022

An analytical procedure is presented which can be used to model the behavior of a polymeric composite panel when subjected to both external loading as well as the high heat flux associated with a fire. The procedure accounts for the elastic and viscoelastic-viscoplastic response, thermal gradients and thermal stresses, and pyrolysis effects. Predictions based on estimated properties for an E-glass/polyester composite panel subjected to a uniaxial tensile load of 250 kN/m (1430 lb/in) and a 1-D heat flux of 10 kW/m2 (22 BTU/hr/in2) are presented. The predicted response is considered to be a reasonable representation of the expected behavior.
Temporal Change of a Parallel Plate Capacitor’s Voltage after Dielectric Insertion
Authors: Oh Youngmin , Jang Taehun , Ha Hyejin , Sohn Sangho
Published: January 2022

The capacitor is a device that can store an electric charge and has a structure with two insulated electrode plates. When a voltage is applied to the capacitor, electric charge accumulates on the plates; current flows during the charge accumulation but does not flow when the charge accumulation is complete. Dielectric inserts are made from a substance that generates a dielectric polarization when an electric field is applied to them. The capacitance C of a parallel plate capacitor filled with dielectric material can be expressed as:
Polarimetry Measurement in a Physics Lab for Food Science Undergraduate Students
Authors: Cescon Ivan , Stefanel Alberto
Published: January 2022

This paper presents a series of experiments that focus on light polarization and polarimetry. Such experiments were conducted with the use of commercial Polaroids, light sensors, and laser pointers, and were designed for an undergraduate food science students physics lab.
Apparent retrograde motions of planets
Authors: Sirola Christopher
Published: January 2022

Thanks to the COVID-19 pandemic, virtually all in-person instruction was shut down across the country in 2020 and beyond. This posed special problems for laboratory-based science courses, as those are defined by the conducting of experiments in person and often with specialized equipment unavailable outside of the classroom. Here I discuss a semester-long project for introductory astronomy that can be performed at home with very basic and inexpensive equipment. And, thanks to the vagaries of the orbits of the planets, variations of this activity can be carried out in many future semesters.
Performing acoustics experiments using inexpensive Bluetooth speakers and smartphone signal generator applications
Authors: Chiaverina Chris
Published: January 2022

The acoustic experiments discussed here are by no means novel; some can be traced back to the 18th century. What may be new to readers is the use of small, low-cost Bluetooth speakers and signal generator applications (apps) to perform them (Fig. 1).
Accuracy of Direct Antimicrobial Susceptibility Testing of Gram-Negative Bacteria from Positive Blood Cultures Using MicroScan System and Value of Using Expert Rules for β-Lactam Agents
Authors: Jacobs Michael R. , Good Caryn E. , Abdelhamed Ayman M. , Bonomo Robert A.
Published: January 2022

Direct antimicrobial susceptibility testing (AST) of positive blood cultures with Gram-negative bacteria produces results within 24 h, compared to 48 to 96 h with conventional methods. Positive clinical blood cultures were studied, supplemented with contrived blood cultures inoculated with a spectrum of resistant isolates.
Tumor Necrosis Factor Alpha Contributes to Inflammatory Pathology in the Placenta during Brucella abortus Infection
Authors: Tsai April Y. , Byndloss Mariana X. , Seyffert Núbia , Winter Maria G. , Young Briana M. , Tsolis Renée M.
Published: January 2022

Research onBrucellapathogenesis has focused primarily on its ability to cause persistent intracellular infection of the mononuclear phagocyte system. At these sites,Brucella abortusevades innate immunity, which results in low-level inflammation and chronic infection of phagocytes.
Protein Kinase C-α Is a Gatekeeper of
Cryptosporidium
Sporozoite Adherence and Invasion
Authors: McCowin Sayo , Petri William A. , Marie Chelsea
Published: January 2022

Cryptosporidium
infection is a leading cause of diarrhea-associated morbidity and mortality in young children globally. Single nucleotide polymorphisms (SNPs) in the human protein kinase C-α (
PRKCA
) gene region have been associated with susceptibility to cryptosporidiosis.
No Science Fair? No Problem. Engaging Students in Science Communication through Peer Review and Publication in a Remote World
Authors: Rodriguez Eddie , Mazzola Michael , Fankhauser Sarah C.
Published: January 2022

Since March 2020, in-person science competitions have been cancelled or moved to a virtual space. This reality has encouraged teachers and students to find alternative ways to disseminate student research and participate in a scientific community.
Addressing Foodborne Illness in Côte d’Ivoire: Connecting the Classroom to the Community through a Nonmajors Course-Based Undergraduate Research Experience
Authors: Smith Marie A. , Olimpo Jeffrey T. , Santillan Karen A. , McLaughlin Jacqueline S.
Published: January 2022

The integration of course-based undergraduate research experiences (CUREs) into science, technology, engineering, and mathematics (STEM) laboratory curricula has provided new avenues to engage students at all levels in discovery-based learning. Empirical research demonstrates that CUREs have the potential to foster students’ development of scientific process and reasoning skills, attitudes, motivations, and persistence in STEM.
A Twist to the Kirby-Bauer Disk Diffusion Susceptibility Test: an Accessible Laboratory Experiment Comparing Haloferax volcanii and Escherichia coli Antibiotic Susceptibility to Highlight the Unique Cell Biology of Archaea
Authors: Schiller Heather , Young Criston , Schulze Stefan , Tripepi Manuela , Pohlschroder Mechthild
Published: January 2022

Archaea, once thought to only live in extreme environments, are present in many ecosystems, including the human microbiome, and they play important roles ranging from nutrient cycling to bioremediation. Yet this domain is often overlooked in microbiology classes and rarely included in laboratory exercises.
Equations of Correlational Magnetodynamics for Ferromagnetic Materials
Authors: Ivanov A. V. , Zipunova E. V. , Khilkov S. A.
Published: January 2022

A new system of equations for correlational magnetodynamics was developed by means of Bogoliubov hierarchy and new approximation for multiparticle distribution functions. The system consists of two equations. One is Landau–Lifshitz–Bloch like equation, and the other describes the evolution of pair correlations. Computational results show that correlational magnetodynamics model match the direct Landau–Lifshitz better than the standard Landau–Lifshitz–Bloch equation.
Preference of grade and lymphovascular invasion over invasive size measurement in stage I lung adenocarcinoma
Authors: Itami Hiroe , Kawaguchi Takeshi , Yoshikawa Daiki , Watanabe Takashi , Terada Chiyoko , Okada Fumi , Uchiyama Tomoko , Takeda Maiko , Ishida Eiwa , Nishimoto Yuko , Okada Hiroshi , Kushibe Keiji , Sawabata Noriyoshi , Ohbayashi Chiho
Published: January 2022

Aims

Although it is necessary to measure the invasive size of lung adenocarcinoma with a lepidic component, it is not uncommon to have trouble in measuring the invasive size of lung adenocarcinoma. This study examined whether there were other stronger prognostic factors than invasive size.

Methods

We characterised the clinicopathological features associated with recurrence-free survival (RFS) of 686 patients with the pathological stage (p-Stage) I lung adenocarcinoma. Moreover, we compared the area under the curve (AUC) values for recurrence between various combinations of pathological-baseline (age & sex & p-Stage based on invasive size) (B(i)) and several prognostic factors, and various combinations of p-baseline based on total tumour size (B(t)) and several prognostic factors.

Results

AUC showed no significant differences between B(i) & new International Association for the Study of Lung Cancer grade (G) or vascular invasion (V), and B(t) & G or V. AUC was the highest in B & G & lymphatic invasion (L) & V. RFS was significantly shorter in patients with G3 OR L(+) OR V(+) than in those with G≤2 AND L(-) AND V(-) in each p-Stage based on invasive size (p-Stage(i)) and p-Stage based on total tumour size (p-Stage(t)) (p<0.05), and there were no significant differences in RFS between each p-Stage(i) and p-Stage(t).

Conclusions

In any invasive size or total tumour size of p-Stage I lung adenocarcinoma, G, L and V are more powerful prognostic factors than the size criteria of p-Stage. Therefore, pathologists should focus on these pathological findings.
Immune checkpoint blockade with anti-programmed cell death 1 (PD-1) monoclonal antibody (mAb) cemiplimab: ongoing and future perspectives in rare genital cancers treatment
Authors: Gambale Elisabetta , Fancelli Sara , Caliman Enrico , Petrella Maria Cristina , Doni Laura , Pillozzi Serena , Antonuzzo Lorenzo
Published: January 2022

Cemiplimab is a highly potent, hinge-stabilized human IgG4 monoclonal antibody (mAb) targeting programmed cell death 1 (PD-1) receptor approved for patients with locally advanced or metastatic cutaneous squamous cell carcinoma (SCC) who are not candidates for curative surgery or curative radiation. Recently, the phase 3 trial EMPOWER-Cervical 1 has investigated cemiplimab in patients with recurrent/metastatic cervical cancer. At interim analysis, overall survival (OS), progression free survival (PFS) and objective response rate (ORR) in overall and SCC populations favored cemiplimab over single agent chemotherapy. Cervical SCCs are the first for incidence among Human Papilloma Virus (HPV) related neoplasms and are highly correlated (about 95%) with the viral infection. Similarly, penile and vulvar SCC may develop on chronic HPV infections or on dermatological chronic conditions (ie, lichen). The molecular and viral similarities between external genital SCC and SCC originating from the cervical epithelium could be the rationale for using cemiplimab to treat locally advanced or metastatic penile and vulvar SCC as well. Some retrospective data have shown that cemiplimab may provide objective response and clinical benefit to some patients with penile or vulvar SCC and is overall safe to utilize in this population. Given the complexity of the immune activation and the considerable variability in tumor biology across patients and tumor types, the identification of biomarkers to warrant patient selection needs to be further explored. Ongoing clinical trials will hopefully shed light on the treatment paradigm of these rare tumors too, with special regard to the ideal combination and sequencing of immunotherapeutic strategies.
Laterality of previous stoke affects endovascular thrombectomy outcomes
Authors: Bageac Devin V , Gershon Blake S , Chada Deeksha , Siddiqui Neha , Majidi Shahram , Fifi Johanna T , De Leacy Reade
Published: January 2022

Background

Investigations into the effect of previous stroke on thrombectomy outcomes have yielded conflicting results, and are limited by small sample sizes. We present the results of a large single center retrospective study aimed at investigating the effect of chronic stroke laterality on thrombectomy outcomes.

Methods

A prospectively maintained database was queried for all thrombectomy cases conducted between December 2014 and January 2020, and patient imaging was prospectively reviewed for evidence of prior supratentorial infarction. Procedural, clinical, and demographic characteristics were recorded, and good clinical outcome was defined as a 90 day modified Rankin Scale (mRS) score of <2 or mRS score unchanged if baseline was >2.

Results

The final analysis cohort included 555 patients, 79 of whom were found to have radiographic evidence of prior chronic infarcts. On univariate analysis, patients with any chronic supratentorial infarct achieved a lower rate of good clinical outcome than patients with no chronic infarct (22.8% vs 41.0%, p=0.0021). With regard to subgroups, this difference remained only in patients with ipsilateral (14.3%, p=0.0018) and bilateral (11.8%, p=0.015) lesions. Patients with chronic contralateral supratentorial infarcts were no less likely to achieve good outcomes (40.7%, p=0.98). After multivariate regression controlling for age, sex, and baseline mRS, chronic ipsilateral infarcts (OR 0.22, CI 0.07 to 0.67) and chronic bilateral infarcts (OR 0.19, CI 0.04 to 0.85) were the only independent predictors of poor outcome in endovascular thrombectomy patients.

Conclusions

In this single center retrospective study of thrombectomy patients with chronic supratentorial infarcts, the laterality of the previous stroke significantly affected the likelihood of good clinical outcomes.
Impact of leukoaraiosis in patients with acute ischemic stroke treated with thrombectomy: a post hoc analysis of the DIRECT-MT trial
Authors: Yi Tingyu , Zhang Yongxin , Chen Wen-huo , Wu Yan-min , Lin Ding-lai , Lin Xiao-hui , Zhang Lei , Xing Peng-fei , Li Tianxiao , Zhang Yongwei , Wang Shouchun , Yang Pengfei , Cai Ming-zhi , Liu Jianmin
Published: January 2022

Background

The influence of leukoaraiosis in patients with acute ischemic stroke (AIS) given intra-arterial treatment (IAT) with or without preceding intravenous thrombolysis (IVT) remains unknown.

Objective

To assess the clinical and radiological outcomes of IAT in patients with or without leukoaraiosis.

Methods

Patients of the direct mechanical thrombectomy trial (DIRECT-MT) whose leukoaraiosis grade could be assessed were included. DIRECT-MT was a randomized clinical trial performed in China to assess the effect of direct IAT compared with intravenous thrombolysis plus IAT. We employed the Age-Related White Matter Changes Scale for grading leukoaraiosis (ARWMC, 0 indicates no leukoaraiosis, 1–2 indicates mild-to-moderate leukoaraiosis, and 3 indicates severe leukoaraiosis) based on brain CT. The primary outcome was the score on the modified Rankin Scale (mRS) assessed at 90 days.

Results

There were 656 patients in the trial, 649 patients who were included, with 432 patients without leukoaraiosis, and 217 (33.4%) patients with leukoaraiosis divided into mild-to-moderate (n=139) and severe groups (n=78). Leukoaraiosis was a predictor of a worse mRS score (adjusted OR (aOR)=0.7 (95% CI 0.5 to 0.8)) and higher mortality (aOR=1.4 (1.1 to 1.9)), but it was not associated with symptomatic intracranial hemorrhage (sICH) (aOR=0.9 (0.5 to 1.5)). IVT preceding IAT did not increase sICH risk for patients with no (aOR=1.4 (0.6 to 3.4)), mild-to-moderate (aOR=1.5 (0.3 to 7.8)), or severe (aOR=1.5 (0.1 to 21.3)) leukoaraiosis.

Conclusion

Patients with leukoaraiosis with AIS due to large vessel occlusion are at increased risk of a poor functional outcome after IAT but demonstrate similar sICH rates, and IVT preceding IAT does not increase the risk of sICH in Chinese patients with leukoaraiosis.
Antiplatelet therapy for standalone coiling of ruptured intracranial aneurysms: a systematic review and meta-analysis
Authors: Takase Hajime , Tatezuki Junya , Salem Mohamed M , Tayama Katsuko , Nakamura Yoshihiko , Burkhardt Jan-Karl , Yamamoto Tetsuya
Published: January 2022

Background

Endovascular embolization using standalone coils is the preferred treatment option for ruptured cerebral aneurysms to avoid the use of dual antiplatelet therapy with stent coiling or endoluminal flow diversion devices. However, it has been reported that patients undergoing the standalone coiling approach are at risk for periprocedural thromboembolism. Therefore, this systematic review and meta-analysis was performed to clarify the risks and benefits of antiplatelet therapy (AT) during coiling procedures performed to treat ruptured aneurysms, including the incidence of early thromboembolic events, hemorrhagic and delayed ischemic events, as well as clinical outcomes.

Methods

A comprehensive search of three databases was performed for articles from inception to June 2021. After fulfilling the inclusion criteria, five studies were included in this meta-analysis and 462 patients with aneurysmal subarachnoid hemorrhage (aSAH) were identified who underwent endovascular standalone coiling treatment. Aneurysm location, patient characteristics, and aSAH grades were comparable between the AT and non-AT groups.

Results

AT significantly decreased the incidence of thromboembolic events immediately after the coiling procedures compared with non-AT (OR 3.42; 95% CI 1.77 to 6.61, p<0.001). The incidences of hemorrhage, delayed ischemia, and clinical outcomes with or without AT were not significantly different between groups.

Conclusions

Although this study showed no beneficial effect of AT on clinical outcomes, the results suggest that AT could be combined with standalone coiling to avoid thromboembolism during the perioperative period. A large prospective study and/or an additional meta-analysis would be required to further investigate how AT benefits standalone coil embolization in aSAH.
Anatomical study and clinical significance of rami communicantes of the lumbar spine
Authors: Zheng Zhiyang , Ma Runxun , Zhang Rusen , Liu Zezheng , Liu Zexian , Chen Junjie , Xu Yejie , Zhou Xinying , Zhao Qinghao , Li Qingchu
Published: January 2022

Background and objectives

Rami communicantes (RC) infiltration and radiofrequency lesions are new techniques for the treatment of discogenic low back pain (DLBP). Their efficacy is controversial, and the classification of RC remains unclear. We aimed to explore the differences between RC and reclassify RC according to their anatomical characteristics.

Methods

Sixteen sides of the lumbar spine from eight adult male embalmed cadavers were dissected. The presence of RC was noted. The morphology, origin, distribution, course, quantity and spatial orientation of RC on the lumbar spine were examined. The length and width of the RC were measured by a caliper.

Results

A total of 213 RC were found in the 8 cadavers in the lumbar region. RC were divided into three types: superficial rami (70, 32.86%), which penetrated the psoas major (PM) and ran above the aponeurosis of the PM; deep rami (125, 58.69%), which ran along the waist of the vertebral body beneath the aponeurosis of the PM; and discal rami, which ran over and adhered to the surface of the intervertebral disc. Superficial rami were divided into two subtypes: oblique rami (45, 21.13%) and parabolic rami (25, 11.74%), which crossed the vertebra and the disc in an oblique and a parabolic course, respectively.

Conclusions

RC should play an important role in the innervation of the lumbar spine. Detailed knowledge of RC in the lumbar region may help surgeons improve the efficacy of infiltration and percutaneous radiofrequency as a supplementary treatment for DLBP.
Mechanisms of shear strain accumulation in laboratory experiments on sands exhibiting cyclic mobility behavior
Authors: Humire Francisco , Ziotopoulou Katerina
Published: January 2022

The factors and mechanisms controlling the accumulation of shear strains of clean uniform sands exhibiting cyclic mobility behavior under level-ground conditions are examined. This phenomenon is investigated through a series of constant-volume cyclic direct simple shear (DSS) tests subjected to uniform and irregular loading conditions, and undrained cyclic element tests collected from the literature. Experimental data show that the rate of shear strain accumulation per loading cycle depends on the relative density, cyclic stress amplitude, and effective overburden stress. Mechanisms of shear strain accumulation are investigated by decoupling the shear strain developed in each loading cycle in two components: γ0, developed at near-zero effective stress, and γd, developed during dilation. Results show that γ0 mostly depends on the shear strain history, while γd depends on the cyclic stress amplitude and relative density. These dependencies of γd and γ0 are used to provide an explanation for the gradual decrease of the rate of shear strain accumulation that is observed while increasing the number of post-triggering loading cycles in tests performed on dense specimens.
Electrochemically deposited molecular thin films on transparent conductive oxide substrate: combined DC and AC approaches for characterization
Authors: Gupta Ritu , Jash Priyajit , Pritam Anurag , Mondal Prakash Chandra
Published: January 2022

Transparent conductive oxides such as indium tin oxide (ITO) substrates are commonly employed as prime materials for optoelectronic applications. Enhancement in functions of such devices often compels stable and robust modification of the ITO substrate to improve its interfacial charge transfer characteristics. Thereby, in this work, naphthyl modifier multilayer films are fabricated on ITO substrate using conventional electrochemical reduction of 1-naphthyl diazonium salts (NAPH-D) via altering its concentration ranging from 2 mM to 12 mM with a step size of 2. Surface coverage was significantly tuned by varying NAPH-D concentration, keeping other parameters such as the number of scans and scan rate constant. For lower concentrations (2 mM), the molecular thickness ∼6 nm was obtained, whereas higher concentrations (12 mM) produced around 15–18 nm thickness. Atomic force microscopy (AFM), cyclic voltammetry, and electrochemical impedance spectroscopy (EIS) in the presence of a ferrocene redox probe also supports the formation of well packed molecular film grown on the ITO surface. Further, the wettability property of the grafted naphthyl film was investigated at different surface coverages and correlated with charge transfer resistance (RCt) obtained from EIS studies.
Bacterial cell wall quantification by a modified low-volume Nelson–Somogyi method and its use with different sugars
Authors: Arenas Thelma , Osorio Aurora , Ginez Luis David , Camarena Laura , Poggio Sebastian
Published: January 2022

The study of peptidoglycan-binding proteins frequently requires in vitro binding assays, in which the isolated peptidoglycan used as a substrate must be carefully quantified. Here, we describe an easy and sensitive assay for peptidoglycan quantification based on a modified Nelson–Somogyi reducing sugar assay. We report the response of this assay to different common sugars and adapt its use to peptidoglycan samples subjected to acid hydrolysis. This method showed better sensitivity than the peptidoglycan quantification method based on the acid detection of diaminopimelic acid. The method described in this work, besides being valuable in the characterization of peptidoglycan-binding proteins, is also useful for the quantification of reducing monosaccharides or polysaccharides after acid or hydrolysis.
Dispersion characteristics of surface plasmon polaritons in a graphene–plasma–graphene waveguide structure
Authors: Ghaffar A. , Umair M. , Alkanhal Majeed A.S. , Khan Y.
Published: January 2022

Theoretical investigations are carried out to study surface wave propagation for a graphene parallel-plate waveguide structure filled with isotropic plasma. The extended wave propagation theory is used. The Kobo formula is used to determine graphene conductivity. Maxwell’s equations (differential form) are used to solve the analytical problem. It is concluded that surface wave propagation can be tuned and controlled by tuning the plasma parameters (plasma frequency and collisional frequency) as well as chemical potential and relaxation time of graphene. Furthermore, the effect of plasma frequency and collisional frequency on the wave attenuation is discussed, and the effect of graphene’s chemical potential, plasma frequency, and collisional frequency on propagation length are also analyzed. The normalized field distribution of plasma medium is also studied. These results may lead to potential applications in optical sensing, communication, and plasma-based optical integrated devices in the gigahertz frequency regime.
CONTAGION ACROSS FINANCIAL MARKETS DURING COVID-19: A LOOK AT VOLATILITY SPILLOVERS BETWEEN THE STOCK AND FOREIGN EXCHANGE MARKETS IN SOUTH AFRICA
Authors: VAN DER WESTHUIZEN CHEVAUGHN , VAN EYDEN RENEÉ , AYE GOODNESS C.
Published: January 2022

The onset of the novel coronavirus pandemic (COVID-19) and previous financial and currency crises have heightened interest in understanding the nature of the interaction of stock market and exchange rate volatility. This paper aims to investigate the interdependence and volatility transmissions between the stock and foreign exchange markets for South Africa over the period of 1979:01–2021:08, including the effect the COVID-19 pandemic has had on the interdependence and volatility transmissions. Through the use of bivariate Exponential Generalized Autoregressive Conditional Heteroscedasticity (EGARCH) modeling, the empirical outcomes from this study provide strong evidence in support of the “stock-orientated” approach, where significant price and volatility spillovers propagate from the stock market into the foreign exchange market, whilst evidence of the “flow-orientated” approach is seen in the second moment and significant shock and asymmetric spillovers from the exchange to stock market are found. The results support the asymmetric and long-range persistence volatility spillover effect and show strong evidence of contagion between stock and foreign exchange markets. These spillovers became more pronounced during the COVID-19 pandemic, confirming heightened contagion in these markets during the periods of crisis. The results heed important implications for not only policymakers who are concerned by the contagion across financial markets and better regulations of these markets to promote economic growth, but also investors and fund managers who seek to hedge investment risks in South Africa.
Hedging Strategy: Concept, Behavior, and Implications for China-ASEAN Relations
Authors: Wang Yuzhu
Published: January 2022

In recent years, more and more scholars have borrowed the terminology “hedging” from financial realm to describe the behaviors of small countries. Furthermore, they defined hedging as the third strategic choices in parallel with balancing and bandwagoning. The current scholarship indicates that most concepts of hedging separate themselves from its original meaning as a financial terminology, lacking a behavioral design of lowering or avoiding uncertain risks. This article redefines hedging and further points out that hedging is in fact a strategy that transfer risks to a third party but fails to remove risks from the system. However, actors in the international system don't share a same risk appetite as investors in the futures market. Therefore, even though small countries adopt the strategy of hedging, the risks cannot be transferred. Hedging will only help countries maintain the balance of power in the region so as to lower the risks when they have chosen the side incorrectly. Hedging has thus become a strategy of deferred-bandwagoning. In practice, hedging occurs when a small country cooperates simultaneously with two great powers, resulting in the balance of power. Or it is also hedging when a small country adjusts its relationship with one great power by measuring its relationship with another. In terms of China-ASEAN relations, the concept of hedging is conducive to understanding why ASEAN countries rely on China for economy but America for security. By the same token, ASEAN countries are able to reject the hugs from great powers when adopting hedging strategy. In that case, it is rarely effective that China can promote its political influence in Southeast Asia through close economic ties, leading to inadequate mutual trust.
Epilogue: personal reflection on geomorphology during 1965–2000 and geomorphological futures
Authors: Slaymaker Olav
Published: January 2022

This chapter is a highly personal reflection on (a) my privileged life as a geomorphologist whose professional career spanned the period 1964–2004, (b) the forces that prevailed on the discipline of geomorphology from 1965 to 2000, (c) the extraordinary influence of individual scientists on my career as well as the discipline as a whole, (d) the many disciplinary paradigms that emerged during the same period and (e) some speculations about geomorphological futures. Geomorphological research and researchers of 1965–2000 were especially significant in relation to the long-term evolution of the discipline in three specific ways: (a) the quantitative revolution in geomorphology was consolidated, (b) new ways of understanding geomorphology were initiated and (c) old disciplinary paradigms were reinvigorated by the quantitative revolution and the newly initiated qualitative ways of understanding geomorphological reality. At the close of my speculation on geomorphological futures I make a plea for deeper geomorphological insight into the interdependence of landforms, landscapes and the well-being of society.