Tribological behaviors of DLC films with hierarchical surface textures under water lubrication: A molecular dynamic simulation

Tribological behaviors of diamond-like carbon (DLC) films with different levels of hierarchical surface textures with lubricant water molecules are investigated through molecular dynamics simulation. The friction forces stabilize at a small value for small normal loads, due to the complete separation between DLC films by water molecules, while friction forces with large normal loads show complicated changes under the cooperation of interfacial evolution and water behaviors. Under large normal loads, friction force increases firstly due to the direct contact of surface textures which are subsequently worn and graphitized, resulting in the temporary stabilization of friction force at a large value. With their further wearing, the amount of interfacial carbon clusters decreases and water molecules distribute evenly at interface, which leads to the gradual decrease and final stabilization of friction force. During the sliding, the water molecules show a restoration in the structure and amount of hydrogen bonds, thus making these molecules play different roles in various stages, i.e., these molecules demonstrate a better diffusion during the friction rise and an enhanced separating effect for DLC films during the friction stabilization. Furthermore, the same amount of water molecules in the one-level hierarchical (L1) model has a larger bearing capacity than that in the two-level hierarchical (L2) model. When the normal load exceeds the bearing capacity of water, the friction force for model L2 is more stable and smaller than that for model L1 after running-in periods due to flattened interfaces and evenly distributed water molecules.

Possible Advantages of S53P4 Bioactive Glass in the Treatment of Septic Osteoarthritis of the First Metatarsophalangeal Joint in the Diabetic Foot

Biomechanically, the great toe with its metatarsophalangeal (MTP) joint plays a key role in standing and walking, making the first MTP joint one of the main predilection sites for ulcer formation, and consequently for bone and joint infection and even amputation. If conservative treatment fails, the main goal of surgery is to remove all infected tissue and preserve the first ray. To improve surgical outcomes, development of new biomaterials like Bioactive Glass S53P4 has begun. Bioactive Glass is useful because of its antibacterial properties; furthermore, its osteostimulative and osteoconductive qualities make the bone substitute particularly suitable as a bone defect filler for the treatment of osteomyelitis. The aim of our retrospective observational study was to compare the outcomes following ulcerectomy with segmental resection of the infected joint and bone and temporary stabilization with an external fixator, both with and without added Bioactive Glass. A comparison of added Bioactive Glass with the traditional surgical treatment in septic osteoarthritis of the first MTP joint showed Bioactive Glass to be effective. During a one-year follow-up, patients with Bioactive Glass required no additional antibiotic therapy or surgical intervention. Bioactive Glass, when applied to the diabetic foot, showed itself to be a safe bone substitute biomaterial.

More than a mob: Parler as preparatory media for the U.S. Capitol storming

On 6 January 2021, a violent mob attacked the United States Capitol. Yet while mob suggests a chaotic and fragmented crowd, networked media had already been working to provide it with “just enough” cohesion, transforming it into a more dangerous political body. This article conceptualizes this preparatory media by examining the “free speech” social media network Parler, drawing on a corpus of ∼350,000 posts from the days leading up to and including the attack. This material empirically demonstrates how media worked to forge connections between disparate camps, to incite participants toward violent activity, and to legitimize this attack as moral or even spiritual. Preparatory media frames events, establishes targets, and sets agendas, providing a degree of order and working against disaggregation online. This temporary stabilization contributes to a more mobilized and organized public body. Rather than prosocial or emancipatory, the Capitol storming demonstrates the far darker potential of this work. Understanding this role of media and intervening within these logics provides one component for preventing future attacks.

Single-Staged Transoral Intra-Lesional Excision of Aneurysmal Bone Cyst of Axis (C2) Vertebra and Temporary Stabilization of Upper Cervical Spine in an Adolescent: A Case Report

Aneurysmal bone cyst (ABC) infrequently occurs within the upper cervical vertebrae. Various therapeutic options have been reported in the literature. We would like to share our experience in managing a case of a 16-year-old girl diagnosed with ABC at the body of axis (C2) vertebra. Serious attention had to be given on the stability of the cervical spine following tumour resection, which can be affected by the mode of treatment chosen. Instability can have a detrimental effect on the cervical spine, in which case may necessitate further surgery. We performed a single-staged intra-lesional curettage via a transoral approach and temporary non-fusion posterior stabilization of C1 lateral mass screw and C2 pedicle screw. The implants were removed after six months once ossification of C2 has taken place to regain full motion of the neck. There was no evidence of recurrence or instability of the cervical spine three years following surgery.

Polish Vector in Politics of Vladimir Monomakh and His Heirs: from the Lyubech Congress to the “Pereyaslavl Crisis”

The question of the system of Russian-Polish interaction during the period of temporary stabilization of political relations in Russia - from the Lyubech Congress (1097) to the end of the Kiev reign of Mstislav the Great (1125-1132) is considered in the article. The authors show that the 12th century is presented in historiography as a time of gradual growth of contradictions between two Christian civilizations, as a transitional period between the Great Schism of 1054 and the IV Crusade (1202- 1204). An attempt is made to consider the relationship between Russia and Poland of the indicated period outside the teleological approach. The authors provide evidence that the thesis of the religious factor as decisive in Russian-Polish relations does not correspond to the political realities of the 10- 30s of the XII century. It is shown that it was the ideological orientation of Vladimir Monomakh towards the crusading movement and the Holy Roman Empire that made it impossible for allied relations between Kiev and Krakow in the first quarter of the 12th century. It has been proved that there was no single policy of Rus towards Poland; the actions of the two sides were situational. The authors come to the conclusion that in Russia and Poland, competing political groups sought to implement their own strategies in relation to the neighboring state.

Regulation strength and technology creep play key roles in global long-term projections of wild capture fisheries

Many studies have shown that the global fish catch can only be sustained with effective regulation that restrains overfishing. However, the persistence of weak or ineffective regulation in many parts of the world, coupled with changing technologies and additional stressors like climate change, renders the future of global catches uncertain. Here, we use a spatially resolved, bio-economic size-spectrum model to shed light on the interactive impacts of three globally important drivers over multidecadal timescales: imperfect regulation, technology-driven catchability increase, and climate change. We implement regulation as the adjustment of fishing towards a target level with some degree of effectiveness and project a range of possible trajectories for global fisheries. We find that if technological progress continues apace, increasingly effective regulation is required to prevent overfishing, akin to a Red Queen race. Climate change reduces the possible upper bound for global catches, but its economic impacts can be offset by strong regulation. Ominously, technological progress under weak regulation masks a progressive erosion of fish biomass by boosting profits and generating a temporary stabilization of global catches. Our study illustrates the large degree to which the long-term outlook of global fisheries can be improved by continually strengthening fisheries regulation, despite the negative impacts of climate change.

Traumatic Unilateral Sixth to Seventh Cervical Vertebral Facet Luxation in a Dog

We describe the surgical reduction of a traumatic, unilateral cervical vertebral facet joint luxation in a large breed dog. Computed tomography (CT) including CT myelography revealed complete luxation of the left articular processes C6 to C7 without fracture of the main weight-bearing structures. There was marked spinal cord compression secondary to the malalignment. Due to the non-ambulatory tetraparetic status, open reduction was chosen as the treatment of choice. After making a dorsal surgical approach to the caudal cervical spine, the luxated articular processes were visible and repositioned. Owing to marked mobility of this joint, temporary stabilization with a nonabsorbable suture between the spinous processes of C6 and C7 was performed and good stability was obtained. The dog recovered uneventfully from the surgery and regained normal ambulation. Follow-up examination including a second CT 9 months after surgery showed no neurological abnormalities and unrestricted motion of the neck. Normal cervical vertebral alignment with moderate osteoarthritis of the right facet joint and mild spondylosis deformans C6 to C7 were present. The present case report shows successful management of a traumatic cervical facet joint luxation without persistent neurological deficits. Open reduction and temporary stabilization with suture material seem to be a valuable method of treatment. The dorsal approach allowed direct inspection of the facet joints with concurrent access to place suture material for temporary stabilization.