Attachment Mechanism Research Articles

Molecular Mechanisms of Shigella Pathogenesis; Recent Advances.

Shigella species are the main cause of bacillary diarrhoea or shigellosis in humans. These organisms are the inhabitants of the human intestinal tract; however, they are one of the main concerns in public health in both developed and developing countries. In this study, we reviewed and summarised the previous studies and recent advances in molecular mechanisms of pathogenesis of Shigella Dysenteriae and non-Dysenteriae species. Regarding the molecular mechanisms of pathogenesis and the presence of virulence factor encoding genes in Shigella strains, species of this bacteria are categorised into Dysenteriae and non-Dysenteriae clinical groups. Shigella species uses attachment, invasion, intracellular motility, toxin secretion and host cell interruption mechanisms, causing mild diarrhoea, haemorrhagic colitis and haemolytic uremic syndrome diseases in humans through the expression of effector delivery systems, protein effectors, toxins, host cell immune system evasion and iron uptake genes. The investigation of these genes and molecular mechanisms can help us to develop and design new methods to detect and differentiate these organisms in food and clinical samples and determine appropriate strategies to prevent and treat the intestinal and extraintestinal infections caused by these enteric pathogens.

Unique Structure and Distinctive Properties of the Ancient and Ubiquitous Gamma-Type Envelope Glycoprotein.

After the onset of the AIDS pandemic, HIV-1 (genus Lentivirus) became the predominant model for studying retrovirus Env glycoproteins and their role in entry. However, HIV Env is an inadequate model for understanding entry of viruses in the Alpharetrovirus, Gammaretrovirus and Deltaretrovirus genera. For example, oncogenic model system viruses such as Rous sarcoma virus (RSV, Alpharetrovirus), murine leukemia virus (MLV, Gammaretrovirus) and human T-cell leukemia viruses (HTLV-I and HTLV-II, Deltaretrovirus) encode Envs that are structurally and functionally distinct from HIV Env. We refer to these as Gamma-type Envs. Gamma-type Envs are probably the most widespread retroviral Envs in nature. They are found in exogenous and endogenous retroviruses representing a broad spectrum of vertebrate hosts including amphibians, birds, reptiles, mammals and fish. In endogenous form, gamma-type Envs have been evolutionarily coopted numerous times, most notably as placental syncytins (e.g., human SYNC1 and SYNC2). Remarkably, gamma-type Envs are also found outside of the Retroviridae. Gp2 proteins of filoviruses (e.g., Ebolavirus) and snake arenaviruses in the genus Reptarenavirus are gamma-type Env homologs, products of ancient recombination events involving viruses of different Baltimore classes. Distinctive hallmarks of gamma-type Envs include a labile disulfide bond linking the surface and transmembrane subunits, a multi-stage attachment and fusion mechanism, a highly conserved (but poorly understood) "immunosuppressive domain", and activation by the viral protease during virion maturation. Here, we synthesize work from diverse retrovirus model systems to illustrate these distinctive properties and to highlight avenues for further exploration of gamma-type Env structure and function.

Attachment ability of combined biomimetic adhesive micro-textures of different shapes

There are various potential applications of biomimetic adhesive solutions including climbing robotic systems, mobile sensor platforms, and biomedical applications such as patches for external use. Achieving resistance to both normal and tangential loads, however, is a critical issue that still needs to be addressed. Some animals have developed exceptional attachment mechanisms based on combined fibrillar elements of different shapes and functions. Experimental investigation of combined biomimetic adhesive micro-textures on tribological performances such as adhesion, friction, and peeling resistance is needed to apply this idea to the design of an artificial texture having similar “biomimetic” properties. In the present study, we demonstrate that combinations of different shapes of biomimetic adhesive micro-textures show increased efficiency under different contact environments and enable long-term adhesive solutions. Our work sheds light on combinations of different element shapes inspired by nature and their adhesive efficiency as a function of the ratio of each biomimetic element, as well as their spatial repartition.

An Experimental Study of Wall Effect on a Hot Settling Sphere in a Newtonian-Fluid-Contained Block Using Photography

In this study, the effect of temperature on the velocity and trajectory of a hot sphere falling in a water block was experimentally investigated. The sphere, 12 mm in diameter, was thrown through the water inside an enclosure at the ambient temperature by an electromagnetic attachment mechanism, and the particle velocity was recorded by a high-speed camera at 2000 fps. Then, using an image-processing algorithm, the real-time particle location was extracted and its velocity was measured. The results of the cold sphere falling test were compared with those obtained from the numerical solving by the governing equations. An electric heater was used to heat the sphere up to 100, 200, and 300 °C in order to investigate the effect of temperature on the sphere. The sphere was thrown upon reaching the desired temperature. By increasing the temperature, the sphere’s velocity was increased up to around 40% of the velocity of the cold sphere. Further, the sphere was thrown from a point in the vicinity of the wall to investigate the wall impact on the particle movement. This led the sphere to deviate from its trajectory, with the deviation in the cold sphere being negligible, i.e., around 30% of the sphere’s diameter. However, the rate of deviation was much more notable upon increasing the temperature. The deviation start point varied depending on the sphere’s temperature, with the highest deviation that was observed for a sphere with a temperature of 100 °C. Ultimately, the sphere traveled in a more extended way, with no deviation from the main trajectory, when its temperature was increased.

Bioprocess inspired formation of calcite mesocrystals by cation-mediated particle attachment mechanism.

Calcite mesocrystals were proposed, and have been widely reported, to form in the presence of polymer additives via oriented assembly of nanoparticles. However, the formation mechanism and the role of polymer additives remain elusive. Here, inspired by the biomineralization process of sea urchin spine comprising magnesium calcite mesocrystals, we show that calcite mesocrystals could also be obtained via attachment of amorphous calcium carbonate (ACC) nanoparticles in the presence of inorganic zinc ions. Moreover, we demonstrate that zinc ions can induce the formation of temporarily stabilized amorphous nanoparticles of less than 20nm at a significantly lower calcium carbonate concentration as compared to pure solution, which is energetically beneficial for the attachment and occlusion during calcite growth. The cation-mediated particle attachment crystallization significantly improves our understanding of mesocrystal formation mechanisms in biomineralization and offers new opportunities to bioprocess inspired inorganic ions regulated materials fabrication.

Study of the Movement Dynamics of a Beet Leaves Harvester

High-quality cutting of beet heads during harvesting reduces the loss of sugar-bearing upper parts of root crops. One of the ways to ensure high quality cutting is to scientifically substantiate the parameters of the machine that harvests the sugar beet leaves; this machine is front-mounted on the tractor’s attachment mechanism. Theoretical calculations established the following. A front-mounted beet topper machine with damping coefficient and the moment of inertia parameters that vary from 0.35 to 1.35 kN s m−1 and from 3000 to 3500 kg m2, respectively, is invariant to the influence of external disturbances in the form of vertical vibrations of the field’s longitudinal profile. These vibrations vary in frequency from 0 to 40 s−1 according to the harmonic function. Setting the tyres stiffness coefficient value of the leaves harvester support-feeler wheels at 315 kN m−1 is characterized by a desirable decrease (up to 41.2%) of the dynamic system’s amplitude–frequency values characteristics when the system is subjected to an external disturbance. With this value of tyre stiffness coefficient, the tyre inflation pressure should not exceed 0.125 MPa.

The Hometown Is Hard to Leave, the Homesickness Is Unforgettable-The Influence of Homesickness Advertisement on Hometown Brand Citizenship Behavior of Consumers.

The hometown brand is symbolic of a hometown and can induce homesickness in consumers. Especially for those who live in other countries, it can stimulate their inner sense of belonging, self-identity, and effectiveness, in turn generating a series of brand behaviors and promoting sustainable brand development. In this study, we adopt a situational experimental research method from the perspective of sense of place theory and social exchange theory in order to assess the regulatory mechanism of place attachment through the mediating mechanism of psychological ownership. In this way, we explore the mechanism underlying the relationship between homesickness advertising (vs. non-homesickness advertising) on the hometown brand citizenship behavior of consumers. Our findings suggest that (1) homesickness advertising has a more positive effect on consumer hometown brand citizenship behavior than non-homesickness advertising; (2) psychological ownership plays a fully mediating role in the relationship between homesickness advertising (vs. non-homesickness advertising) and consumer hometown brand citizenship behavior; and (3) place attachment plays a moderating role in the influence of homesickness advertising (vs. non-homesickness advertising) on the hometown brand citizenship behavior of consumers through psychological ownership.

Synthesis of Silver Nanowires Using a Polyvinylpyrrolidone-Free Method with an Alpinia zerumbet Leaf Based on the Oriented Attachment Mechanism.

In this study, silver nanowires (AgNWs) were successfully synthesized by using a polyvinylpyrrolidone (PVP)-free hydrothermal method with an Alpinia zerumbet leaf chunk as a reducing agent and template. Meanwhile, the mechanism of biomass synthesis of AgNWs is also explored. The AgNWs have a diameter of ∼77 nm and a length of ∼10 μm. During the hydrothermal process, the biomass initially serves as a reducing agent to reduce silver ions. As the reaction proceeds, the biomass will form a pipe-shaped soft template by hydrothermal carbonization. Silver ions are adsorbed and reduced along the pipe-shaped soft templates to form silver nanorods, and adjacent nanorods are merged to AgNWs. Thus, AgNWs are grown along the pipeline soft template based on the oriented attachment mechanism. Inspired by this, the mechanism of the polyol method was further investigated. In the initial growth stage, AgNWs synthesized by the polyol method have a V-shaped notch. Therefore, AgNWs synthesized by the polyol method may also grow on the basis of the oriented attachment mechanism with PVP as a template.

Design and Control of a Novel Detachable Driving Module for Electrification of Manual Wheelchairs

We developed a detachable electric module that converts a manual wheelchair into an electric wheelchair. The existing electric module requires several parts to be fastened to the wheelchair, which complicates its assembly. In addition, because the overall size of the wheelchair increases after its assembly and the turning radius increases compared to the manual wheelchair, controlling the wheelchair becomes difficult for the user. To compensate for these shortcomings, a new type of electric module composed of two omni-wheel driving units is proposed in this study. Because the two modules can independently move forward or backward and change directions, the same movement as that of the existing manual wheelchair is possible. In addition, a mechanism for easy attachment and detachment is proposed and its versatility is verified by mounting it on various wheelchairs. For the stable operation of the module, field-oriented control was applied, and the wheelchair was controlled for stably moving against external forces and ground disturbances according to the module mounting location. A driving test was conducted according to the mounting location of the developed module, and the proposed driving module and applied algorithm were verified through statistical analysis.

Enhancing Shear Strength of Bonding Materials Used for Asphalt Concrete and Composite Pavement Layers

A tack coat is a thin cut-back cement or asphalt emulsion coating applied on an existing non-absorbent pavement. A good bonding between the asphalt and concrete is necessary to provide sufficient structural strength. Poor adhesion will result in shear failure. The shear test is one of the basic tests to determine bond strength. This study aims to quantify the best shear resistance obtained using three types of cut-back asphalts (RC70, RC800 modified with polymer 4.5% and MC70), PG (76-10) modified asphalt cement with polymer 4.5%, Sikadur®-31 CF usage at elevated temperatures between +25°C and +45°C and Nitomortar TC2000 epoxy from Fosrok company. All are applied on concrete surfaces with an application rate of 0.5kg/m2 except for Nitomortar, which depends on layer thickness ranges between (1-2.5) mm instead of the application rate. A special attachment and loading mechanism were designed to facilitate the measurement of the asphalt-to-concrete contact shear strength in Al-Ahmad Lab-Baghdad. Vertical shear force is applied to a multiple-layer sample with a 0.25 kN/sec rate until the failure occurs at the interface. The final result of this test is stated in terms of the maximal force or power needed to break the bond. The average shear strength of tack coat materials is (0.049, 0.0455, 0.0085, 0.677, 1.088, 1.361) MPa Respectively. It concluded that Fosrok epoxy has the maximum shear strength. Also, adding polymer to asphalt increased the viscosity. All materials used enhanced the shear strength of bonding materials used for asphalt concrete and composite pavement layers

Atomistic modeling of thermal effects in focused electron beam-induced deposition of Me$$_2$$Au(tfac)

The role of thermal effects in the focused electron beam induced deposition (FEBID) process of Me$_2$Au(tfac) is studied by means of irradiation-driven molecular dynamics simulations. The FEBID of Me$_2$Au(tfac), a commonly used precursor molecule for the fabrication of gold nanostructures, is simulated at different temperatures in the range of $300-450$ K. The deposit's structure, morphology, growth rate, and elemental composition at different temperatures are analyzed. The fragmentation cross section for Me$_2$Au(tfac) is evaluated on the basis of the cross sections for structurally similar molecules. Different fragmentation channels involving the dissociative ionization (DI) and dissociative electron attachment (DEA) mechanisms are considered. The conducted simulations of FEBID confirm experimental observations that deposits consist of small gold clusters embedded into a carbon-rich organic matrix. The simulation results indicate that accounting for both DEA- and DI-induced fragmentation of all the covalent bonds in Me$_2$Au(tfac) and increasing the amount of energy transferred to the system upon fragmentation increase the concentration of gold in the deposit. The simulations predict an increase in Au:C ratio in the deposit from 0.18 to 0.25 upon the temperature increase from 300 K to 450 K, being within the range of experimentally reported values.

The Evolving Bipartite Network and Semi-Bipartite Network Models with Adjustable Scale and Hybrid Attachment Mechanisms

The Evolving Bipartite Network and Semi-Bipartite Network Models with Adjustable Scale and Hybrid Attachment Mechanisms

Efficacy and accuracy of Invisalign attachments: an updated systematic review

Background: The primary purposes of Invisalign® technology are to treat minor to moderate crowding problems and patch up minute cracks. But more recent research and development have made it possible to cure more complex malocclusions. Although the accuracy of Invisalign-assisted orthodontic tooth movements has been researched, the effectiveness of various attachment methods and other aligner factors has not been thoroughly assessed. This study aimed at assessing the accuracy and efficacy of the Invisalign attachment mechanism as described in the most recent publications. Method: A systematic assessment of research examining the precision and efficacy of Invisalign attachments between 2019 and 2022 was performed employing Google Scholar and PubMed databases. The keywords were "efficacy, accuracy, Invisalign attachments, clear aligners, Invisalign®, invisible orthodontics, treatment results," which were used in various combinations. Original research describing the precision and effectiveness of the Invisalign attachments and full-text papers met the criteria for inclusion. Results: Only 8 articles out of 14 met the requirements for inclusion. Six studies were retrospective, one was prospective observational research, and one was a case-series investigation. Together, they involved 621 people. Even though Invisalign® orthodontic treatment is widely used, aside from the non-extraction treatment of mild to moderate malocclusions in non-growing patients, there are presently no definitive recommendations on additional indications of the system based on trustworthy scientific evidence. Invisalign attachments, transparent aligners, and full-text studies demonstrated its efficacy in the non-extraction correction of mild to moderate malocclusions in patients who were not growing. Conclusion: Despite the large number of studies examined in this study, evaluations of treatment results need to be cautious due to the significant heterogeneity. For a broad spectrum of malocclusions and expanding patient populations, further research involving parallel arm RCTs or carefully planned prospective trials is necessary to develop solid clinical recommendations.

An Aerial-Wall Robotic Insect That Can Land, Climb, and Take Off from Vertical Surfaces.

Insects that can perform flapping-wing flight, climb on a wall, and switch smoothly between the 2 locomotion regimes provide us with excellent biomimetic models. However, very few biomimetic robots can perform complex locomotion tasks that combine the 2 abilities of climbing and flying. Here, we describe an aerial-wall amphibious robot that is self-contained for flying and climbing, and that can seamlessly move between the air and wall. It adopts a flapping/rotor hybrid power layout, which realizes not only efficient and controllable flight in the air but also attachment to, and climbing on, the vertical wall through a synergistic combination of the aerodynamic negative pressure adsorption of the rotor power and a climbing mechanism with bionic adhesion performance. On the basis of the attachment mechanism of insect foot pads, the prepared biomimetic adhesive materials of the robot can be applied to various types of wall surfaces to achieve stable climbing. The longitudinal axis layout design of the rotor dynamics and control strategy realize a unique cross-domain movement during the flying-climbing transition, which has important implications in understanding the takeoff and landing of insects. Moreover, it enables the robot to cross the air-wall boundary in 0.4 s (landing), and cross the wall-air boundary in 0.7 s (taking off). The aerial-wall amphibious robot expands the working space of traditional flying and climbing robots, which can pave the way for future robots that can perform autonomous visual monitoring, human search and rescue, and tracking tasks in complex air-wall environments.

Gender differences in brain response to infant emotional faces

Infant emotional stimuli can preferentially engage adults’ attention and provide valuable information essential for successful interaction between adults and infants. Exploring the neural processes of recognizing infant stimuli promotes better understandings of the mother-infant attachment mechanisms. Here, combining task-functional magnetic resonance imaging (Task-fMRI) and resting-state fMRI (rs-fMRI), we investigated the effects of infants’ faces on the brain activity of adults. Two groups including 26 women and 25 men were recruited to participate in the current study. During the task-fMRI, subjects were exposed to images of infant emotional faces (including happy, neutral, and sad) randomly. We found that the brains of women and men reacted differently to infants’ faces, and these differential areas are in facial processing, attention, and empathetic networks. The rs-fMRI further showed that the connectivity of the default-mode network-related regions increased in women than in men. Additionally, brain activations in regions related to emotional networks were associated with the empathetic abilities of women. These differences in women might facilitate them to more effective and quick adjustments in behaviors and emotions during the nurturing infant period. The findings provide special implications and insights for understanding the neural processing of reacting to infant cues in adults.

Metabolic reconstruction of the near complete microbiome of the model sponge Ianthella basta.

Many marine sponges host highly diverse microbiomes that contribute to various aspects of host health. Although the putative function of individual groups of sponge symbionts has been increasingly described, the extreme diversity has generally precluded in-depth characterization of entire microbiomes, including identification of syntrophic partnerships. The Indo-Pacific sponge Ianthella basta is emerging as a model organism for symbiosis research, hosting only three dominant symbionts: a Thaumarchaeotum, a Gammaproteobacterium, and an Alphaproteobacterium and a range of other low abundance or transitory taxa. Here, we retrieved metagenome assembled genomes (MAGs) representing >90% of I. basta's microbial community, facilitating the metabolic reconstruction of the sponge's near complete microbiome. Through this analysis, we identified metabolic complementarity between microbes, including vitamin sharing, described the importance of low abundance symbionts, and characterized a novel microbe-host attachment mechanism in the Alphaproteobacterium. We further identified putative viral sequences, highlighting the role viruses can play in maintaining symbioses in I. basta through the horizontal transfer of eukaryotic-like proteins, and complemented this data with metaproteomics to identify active metabolic pathways in bacteria, archaea, and viruses. This data provide the framework to adopt I. basta as a model organism for studying host-microbe interactions and provide a basis for in-depth physiological experiments.

Scale-free growth in regional scientific capacity building explains long-term scientific dominance

The regional capability of performing front-running research and technological development has been identified as a necessary condition for future wealth creation. The quality and amount of scientific capabilities in specific fields vary dramatically across different world regions. Capabilities, knowledge, and skills are embodied by scientists working in research institutions or companies. The conditions for the emergence of a leading regional scientific environment – and the resulting early technological leadership – are poorly understood. The existence of a critical mass – the threshold above which a region can build comparably strong scientific capabilities – of scientists is often assumed. Using a unique dataset of global scientific activity and researcher mobility over several decades, we present empirical evidence in three scientific areas (semiconductor research, embryonic stem cells, and Internet research) that the process of scientific knowledge accumulation is remarkably general and applies to practically all regions. Regional knowledge accumulation data obtained from an analysis of scientists’ geolocated trajectories follow a preferential attachment mechanism characterized by a sub-linear kernel with a robust growth exponent. Scale-free growth patterns suggest that regions that move early into new technologies tend to dominate the corresponding scientific fields. We find no evidence that critical mass is required to achieve prolonged scientific dominance. We propose a simple preferential attachment model that explains the empirical data and allows us to understand deviations from the growth exponent as focused interventions to strategically attract scientists at regional level. We demonstrate this explicitly for China in the three scientific fields examined.

An Investigation into the Trend Stationarity of Local Characteristics in Media and Social Networks

We studied the evolution of complex social networks over time. The elements of the networks are users, and the connections correspond to the interactions between them. At a particular moment in time, each node of a complex network has such characteristics as its degree, as well as the total degree of its neighbors. Obviously, in the process of network growth, these characteristics are constantly changing due to the fact that new edges are attached to this node or its neighbors. In this paper, we study the dynamics of these characteristics over time for networks generated on the basis of a nonlinear preferential attachment mechanism, and we find both the asymptotics of their expected values and the characteristics of their spread around the mean. In addition, we analyze the behavior of these local characteristics for three real social networks. The applicability of the findings to actual problems in the study of social media in the digital humanities is discussed.

Sealing ability in vitro study and biocompatibility in vivo animal study of different bioceramic based sealers.

The effectiveness of root canal therapy in endodontic practice is largely determined by providing a compact fluid-tight closure at the apex of the root canal, which inhibits irritant entry and buildup, which leads to a biological breakdown of the attachment mechanism and failure. During obturation, along with gutta-percha, root canal sealers are employed to fill voids and seal root canals. Root canal sealers come in a variety of shapes and sizes, each with its own set. Evaluation of sealing ability in vitro study by using scanning electron microscopy(SEM) and biocompatibility in vivo animals study of BioRoot RCS and meta Biomed bio_ceramic sealer (CeraSeal RCS) and compared the findings with that of Zinc oxide eugenol (ZOE) sealer as control. This study utilized two bio_ceramic sealers (BioRoot RCS and meta Biomed bio_ceramic sealer (CeraSeal RCS) and compared the findings with that of ZOE sealer as control. Biocompatibility was determined by examining histopathological biopsy specimens collected from rabbits. Each rabbit had four dentin tubes implanted into the subcutaneous tissues, one for BioRoot RCS, one for CeraSeal RCS, and one for ZOE RCS, with the fourth tube being empty haematoxylin and eosin were used to stain histological sections, and a light microscope was used to evaluate them. Extracted human single canal premolars were used to evaluate the sealing ability. The root canals were divided into three sections (coronal, middle, and apical). SEM was used to assess the adhesion quality at the sealer-dentin interface. BioRoot and CeraSeal sealers have excellent sealing adaptation and biocompatibility, as well as rapid tissue recovery, while ZOE sealers have a slower recovery of inflammatory reaction results when compared to bio_root and ceraSeal sealers, as well as a less sealing adaptation than the two other bio_ceramic sealers. In general, the two bioceramic sealers tested were biocompatible and capable of sealing or adhesion. While ZOEhad less adherence ability and less biocompatibility.

The mechanism of body-mind integration in the formation of destination attachment: A comparison of first-time and repeat tourists.

By constructing a person-body-mind-place framework of destination attachment, this study explores the physical and mental formation mechanism of destination attachment and examines its dynamics between first-time and repeat tourists. The present study found that multisensory impressions can, directly and indirectly, affect destination attachment through emotional and cognitive psychological mediation. There are differences between first-time tourists and repeat tourists in terms of this mediation path. As the frequency of travel increases, the influence of multisensory impressions gradually increases. The formation of destination attachment is dominated by emotion for first-time tourists, whereas it is dominated by cognition for repeat tourists. Based on these findings, theoretical and practical implications are presented.