Box Folds Research Articles

Analysis of experience in optimizing the operation of an automated production line for folding cardboard boxes

The object of research is an automated system for controlling the bending mechanisms of the folding-gluing line for cardboard packaging products. In the work, the ways of optimization and the development of an automated control system for the bending mechanisms of the folding and gluing line, which makes it possible to fold various structures and standard sizes of cardboard boxes using modern automation tools based on programmable logic controllers, were carried out in the work. A mathematical model has been proposed to describe operations on the folding-gluing line. Based on the model, a methodology has been developed for calculating the parameters of the automated control system for the box folding production line, depending on the technical parameters of the line and the parameters of the boxes to be bent. This will make it possible to choose optimal technological modes of the production process and obtain high quality parameters of cardboard packaging products. To verify the mathematical model of the production line, software has been developed in the Delphi development environment, which was applied with the developed automated production process control system based on a programmable logic controller (PLC) and an operator panel. This produced a number of results, in particular, controlling the speed of the hook bend in proportion to the speed of the line. And also provided an opportunity to increase line speed and, accordingly, production productivity. It has been possible to change the mutual location of system elements, which made it possible to reduce the distance between workpieces and increase the capacity of the line tape by 30 %. The obtained research results were implemented at the production enterprise of typographic products «Dinas» (Zaporizhzhia, Ukraine), which contributed to the improvement and optimization of production processes. Conducting further research will provide an opportunity to expand the proposed methodology for use on all types of folding and gluing lines.

Origami Box Folding Exercise: A laparoscopic box simulation training and assessment method in facilitating laparoscopic psychomotor skills with minimal preparation

ObjectiveLaparoscopic box simulation training is widely recognized as an assessment tool to facilitate psychomotor skills especially for novice surgeons. However, current commercialized training modules including pegs, gauze, clips, pins etc. are generally costly and relatively inaccessible. We introduce a simple and pioneer surgical training drill, the Origami Box Folding Exercise (OBFE), based on the validated evaluating system of objective structured assessment of technical skills (OSATS) constructed with the scoring system of procedure-specific checklist (PSC) and global rating scale (GRS). Materials and methodsFace and content validation of the OBFE and OSATS are evaluated by five endoscopic experts from two medical centers in Taiwan. This is a prospective observational study analyzing the pre-test/post-test result of OBFE from 37 participants in two individual workshops as training and evaluating method for laparoscopic psychomotor skills. Both the pre and post tests are video recorded with a time limit of 5 min graded by two independent evaluators based on the OSATS scoring system. ResultsThe reliability of PSC, GRS, and intergroup value between PSC and GRS were 0.923, 0.926 and 0.933, respectively. Inter-rater reliability of PSC, GRS, and both were 0.985, 0.932 and 0.977, respectively. Construct validity of PSC and GRS were statistically significant, with p-value 0.006 and 0.001, respectively. ConclusionOBFE enhances laparoscopic psychomotor skills with requirement of a single piece of paper. The associated OSATS tool for a 5-min OBFE test was validated. OBFE training is an efficient training and assessment system to promote psychomotor skills in laparoscopic box simulation drill which requires simple and economical preparation.

Formation mechanism and hydrocarbon exploration significance of the box fold in the Qiulitage structural belt, the Kuqa Depression, Tarim Basin, China

Clarifying the deformation characteristics and formation mechanisms of the box fold in the eastern Qiulitage structural belt can provide important references for the reconstruction of the evolution process and petroleum exploration in the Qiulitage structural belt. As a result of the deep geological structure displayed by seismic data and characteristics of faults and fractures within the box fold, the mechanical mechanism and structural evolution of the box fold in the eastern Qiulitage structural belt were investigated, along with the genesis and significance of hydrocarbon exploration of faults and fractures within the box fold. The results show that the surface box fold in the Qiulitage structural belt was formed via the conjugate kinking of the supra-salt structural layer, driven by the intensive southward compression during the Middle and Late Himalayan movements. The box fold has experienced three evolution stages, namely, the tectonically-inactive stage before the deposition of the Kuqa Formation, the fold rudiment stage during the early to middle deposition of the Kuqa Formation (Kuqa period), and the stage of fold finalization and uplift-denudation. The front flank of the box fold develops north-dipping thrust faults and network fracture systems formed during the early to middle Kuqa period and cemented by gypsum due to the precipitation of deep, high-salinity formation water. However, later faulting can cut and dislocate the cement. The upper fold core develops north-dipping tensile faults and near EW tensile fractures, while the lower fold core is associated with small back-thrust structures and near NS shear fractures. The neutral plane is expected to be in the middle-lower part of the fold. The back-flank of the box fold develops south-dipping back-thrust faults and near EW interlayer shear fractures caused via interlayer detachment. The core and back flank of the fold were less affected by the high-salinity formation water, leaving faults and fractures with no considerable cementation. The kink zone and its surroundings have high storage and flow capacities and thus the potential to and develop oil and gas reservoirs. Correctly interpreting kink zones in concealed areas can help expand the scale of original oil and gas reservoirs or discover new petroleum exploration domains. In the Qiulitage structural belt, the connection between deep and shallow fault systems leads to the migration of deep hydrocarbons to shallow layers and subsequent accumulation. The structural-lithologic oil and gas reservoir formed in the Paleogene thin sand layers of the upper part of the Lower Cretaceous and the structural oil and gas reservoir formed in supra-salt sandstone layers of the surface box fold are among The potential exploration domains in shallow layers.

Optimization of the manufacturing process of cardboard packaging with fuzzy logic: Case study company in the industrial polo of manaus

This study arose from the need to meet the demand for manufacturing LCD monitors with cardboard packaging, with less assembly complexity, substantially reducing the amount of folds in the packaging, due to the use of a large number of collaborators involved in the assembly of standard cardboard boxes. The focus of the work is directly on reducing the amount of box folds, maintaining current factory layouts and complying with basic dimensional requirements, geometry, mechanical strength, and customer acceptance criteria (quality tests). The methods used for the purposes of the research were exploratory and descriptive, having as a research instrument applied in the form of observation and analysis in the various stages of the development of the packaging project, proposing a new approach to the concept of boxes that would meet the needs of the modern production and development needs. In this case, we propose, with Fuzzy logic, to validate the results obtained with the new layouts of boxes, as well as other recommendations relevant to the proposed study, creating subsidies to answer the problem raised.

Fabrication of Semi_Automated Box Transport Mechanism

The main concept behind our project is replacement of treadmill mechanism for small scale industries which is fully functional, easy to use, highly accessible and easily maintainable. The answer for this is Box Transport Mechanism as it is a construction of links and joints it is easy to construct and to maintain. compared to treadmill it is cheap and efficient. The results from this project can be used by many small-scale industries and in-house industries where conveyor system is not accessible. This invention relates to improvements in transfer and conveying devices, and it relates particularly to devices for transferring set-up cardboard boxes from a box folding or forming machine to the operator of a semi-automatic box wrapping machine. Many manufacturers who wrap or cover cardboard boxes for packaging candies, cakes, and other confections, cosmetics and other articles require this setup. These set-up boxes are transferred by means of a conveyor to an operator, who picks up the boxes and places and centers them on wrappers with which the boxes are to be covered. The boxes and wrappers are then conveyed to a box wrapping machine where the wrapper is folded around and glued to the box. Usually, the operation of the wrapping machine is controlled by means of a switch actuated by the box forming machine so that their operating speeds are related to each other

Geological and seismic evidence for the tectonic evolution of the NE Oman continental margin and Gulf of Oman

AbstractLate Cretaceous obduction of the Semail ophiolite and underlying thrust sheets of Neo-Tethyan oceanic sediments onto the submerged continental margin of Oman involved thin-skinned SW-vergent thrusting above a thick Guadalupian–Cenomanian shelf-carbonate sequence. A flexural foreland basin (Muti and Aruma Basin) developed due to the thrust loading. Newly available seismic reflection data, tied to wells in the Gulf of Oman, suggest indirectly that the trailing edge of the Semail Ophiolite is not rooted in the Gulf of Oman crust but is truncated by an ENE-dipping extensional fault parallel to the coastline. This fault is inferred to separate the Semail ophiolite to the SW from in situ oceanic Gulf of Oman crust to the NE. It forms the basin margin to a “hinterland” basin formed atop the Gulf of Oman crust, in which 5 km of Late Cretaceous deep-water mudstones accumulated together with 4 km of Miocene and younger deep-water mudstones and sandstones. Syndepositional folding included Paleocene–Eocene folds on N-S axes, and Paleocene to Oligocene growth faults with roll-over anticlines, along the basin flank. Pliocene compression formed, or tightened, box folds whose axes parallel the modern coast with local south-vergent thrusts and reversal of the growth faults. This Pliocene compression resulted in large-scale buckling of the Cenozoic section, truncated above by an intra-Pliocene unconformity. A spectacular 60-km-long, Eocene(?) to Recent, low-angle, extensional, gravitational fault, down-throws the upper basin fill to the north. The inferred basement of the hinterland basin is in situ Late Cretaceous oceanic lithosphere that is subducting northwards beneath the Makran accretionary prism.

Box Folding Machine Design by Using Product Design Method Functional Based Model

In order to meet the growing demand for products, scientists have been developing product design methods. Based on the existing product design methods and the Oregon State University’s Modern Product Design, this report talks about the improved product design method and uses this method to design one new cases. The example case is box folding machine. It consists of a feeding system, a transport system, a folding system, and an exporting system. The core part folding system consists of a two-step folding system. By folding twice, the finished box is wrapped and self-locking. Through the final estimation, the folding speed of the box folding assembly line is five times that of manual folding. As a result, the box folding assembly line can meet the needs of fast folding.

The Effect of Bait on The Catch Composition of Square Folding Trap in Rawa Pening Semarang Regency

This study aims to determine the effect of the type of bait on the composition of the catch fish, catch rate, and trap rate using square folding traps. The study was conducted at three fishing locations in October 2019-January 2020 using the experimental fishing method. The operation of square folding traps was done by a total of 60 units. The types of bait used are golden snails, shrimp paste, and trash fish. Fish catches were recorded in number, type, length, and weight, and analyzed using one-way anova test and kruskal wallis test. The composition of the square folding traps catches consists of six species. Marble goby (Oxyeleotris marmorata) is the most dominant catch (60%). The highest catch rate was obtained from box folding traps which were given golden snail bait at 173.50 g/trip, then trash fish bait at 76.88 g/trip and shrimp paste feed at 59.22 g/trip. The highest trap rate is golden snail bait of 12.33%. The bait treatment gives a real difference to the amount and weight of the catch, the golden snail bait gives the highest total number and weight of the catch compared to other baits.

Efficient Algorithm for Box Folding

For a given polygon $P$ and a polyhedron $Q$, the folding problem asks if $Q$ can be obtained from $P$ by folding it. This simple problem is quite complicated, and there is no known efficient algorithm that solves this problem in general. In this paper, we focus on the case that $Q$ is a box, and the size of $Q$ is not given. That is, input of the box folding problem is a polygon $P$, and it asks if $P$ can fold to boxes of certain sizes. We note that there exist an infinite number of polygons $P$ that can fold into three boxes of different sizes. In this paper, we give a pseudo polynomial time algorithm that computes all possible ways of folding of $P$ to boxes.

Structural styles and decoupling in stratigraphic sequences with double décollements during thin-skinned contractional tectonics: Insights from numerical modelling

Six series of particle-based numerical experiments were performed to simulate thin-skinned contractional tectonics in stratigraphic sequences with double décollements during horizontal shortening. The models were assigned with varying rock competence, depth and thickness of the upper décollement, which resulted in significantly different styles of deformation and decoupling characteristics above and below the upper décollement. The models composed of the least competent material produced distributed sinusoidal detachment folds, with many shallow structures profoundly decoupled from the deep-seated folds. The models composed of a more competent material are dominated by faulted box folds, with minor disharmonic folds developed in their limbs. In contrast, the results of models composed of the most competent material are characterised by localised piggyback thrusts, fault-bend folds and pop-up structures with tensile fractures developed in fold hinges. Depth of the upper décollements also plays an important role in controlling structural decoupling, i.e. the shallower the upper décollements, the higher the degree of decoupling becomes. Thicker upper décollements can provide sufficient mobile materials to fill fold cores, and contribute to the formation of secondary disharmonic folds, helping enhance structural decoupling. Our modelling results are comparable to the structural features exhibited in the Dezful Embayment of the Zagros Fold-and-Thrust Belt with the Miocene Gachsaran Formation acting as the shallow upper décollement, and the Fars with the Triassic Dashtak Formation as its intermediate décollement. This study demonstrates that rock competence, depth and thickness of the upper décollements can jointly affect the structural styles and decoupling. Our modelling results are instructive for structural interpretation of deep zones in fold-and-thrust belts that exhibit distinct structural decoupling features.

Combined control of décollement layer thickness and cover rock cohesion on structural styles and evolution of fold belts: A discrete element modelling study

A series of numerical experiments based on the discrete element method were performed to simulate the formation of fold belts, with varied décollement layer thickness and cover rock cohesion, to investigate their controls on structural styles of fold belts. Each model consists of a weak, unbonded basal décollement layer with a relatively low to high thickness, and a bonded cover with a relatively low to high cohesive strength. Horizontal shortening of the particle assemblage was achieved by horizontal motion of a vertical boundary wall, resulting in deformations in the system. The results show that shortening was mainly accommodated by detachment folds (sinusoidal and box folds), fault-related folds and opening-mode fractures in the models. The combination of a lower cohesion and a thinner décollement resulted in more distributed strain and a larger number of folds, whilst the combination of a higher cohesion and a thicker décollement led to more pronounced strain localisations in fewer folds. Surface uplift and fold amplitude (diapir height) are mainly positively affected by the décollement thickness, i.e. the thicker the décollement is, the greater the surface uplift and fold amplitude are. The propagation rate of deformation is predominately controlled by the cover rock cohesion. A lower cohesion led to a higher propagation rate of deformation. The model with a relatively low cohesion and décollement thickness produced regularly-spaced box folds, which are comparable to those in the southern Zagros Fold-and-Thrust Belt. The models presented demonstrate that the combined effect of décollement layer thickness and cover rock cohesion can play a critical role in the structural styles and kinematic evolution of fold belts.

The role of flexural slip during the development of multilayer chevron folds

Flexural slip has long been recognized as a crucial mechanism during the development of chevron folds and a conceptual understanding of its role has been presented by analogue and kinematic models and field studies. This study uses 2D finite element analysis to provide a thorough quantitative evaluation of flexural slip based on buckling of effective single layers1 and true multilayers1. The analysis of the results describes the spatial and temporal evolution of flexural slip and documents the resulting fold shapes. The results show that effective single layer buckle folds amplifying the dominant wavelength, λd, do not result in chevron folds in any of the situations considered - varying initial perturbation, viscosity contrast and friction coefficient. Slip initiates early, and a transition from sinusoidal or parabolic to box folds is common. Reducing the amplified wavelength (~10% of λd), results in systematic chevron folds. For true multilayer buckle folds, systematic chevron folds featuring hinge collapse develop regardless of the initial perturbation used. The ratio of incompetent to competent layer thickness, s/h, is a crucial parameter: for s/h > 1, flow dominates and slip is not initiated; for s/h < 1, flexural slip initiates, and the lower s/h becomes, the more slip surfaces are activated. The occurrence of slip is localized near the hinge zone, which reflects the mechanical decoupling of the competent and incompetent beds. The results also document that flexural slip initiates during the later stages of folding (for limb dip angles >53°) and that sinusoidal or parabolic folds nearly “instantaneously” change shape to chevron folds during a short period of slip initiation and termination, thus confirming the phenomenon of limb lock up. For models incorporating permeability contrasts, the development of deformation induced overpressure leads to an earlier initiation of flexural slip.

Flexural-slip during visco-elastic buckle folding

Flexural-slip is considered as an important mechanism during folding and a general conceptual and qualitative understanding has been provided by various field studies. However, quantitative evidence of the importance of the flexural-slip mechanism during fold evolution is sparse due to the lack of suitable strain markers. In this study, 2D finite element analysis is used to overcome these disadvantages and to simulate flexural-slip during visco-elastic buckle folding. Variations of single and multilayer layer fold configurations are investigated, showing that flexural-slip is most likely to occur in effective single layer buckle folds, where slip occurs between contacts of competent layers. Based on effective single layer buckle folds, the influence of the number of slip surfaces, the degree of mechanical coupling (based on the friction coefficient), and layer thickness, on the resulting slip distribution are investigated. The results are in agreement with the conceptual flexural-slip model and show that slip is initiated sequentially during the deformation history and is maximum along the central slip surface of the fold limb. The cumulative amount of slip increases as the number of slip surfaces is increased. For a lower degree of mechanical coupling increased slip results in different fold shapes, such as box folds, during buckling. In comparison with laboratory experiments, geometrical relationships and field observations, the numerical modeling results show similar slip magnitudes. It is concluded that flexural-slip should represent a significant contribution during buckle folding, affecting the resulting fold shape for increased amounts of slip.

Architecture of Glaciotectonic Complexes

Glaciotectonic studies are an integrated part of the Quaternary geological research carried out by the Danish geological survey. Almost all the hilly areas in Denmark were created or affected by glaciotectonic deformations, and the features are included in the mapping of surface near deposits. For the mapping and support of constructing 3D geological models a classification of architecture of glaciotectonic complexes is suggested. The important elements for classification of architecture are the surfaces. Four orders of surfaces are defined for glaciotectonic complexes: first-order surfaces are décollement surfaces and glaciotectonic unconformities; second-order surfaces are ramps and flats—the thrust faults; third-order surfaces are folded beds—anticlines and synclines; and fourth-order surfaces are small scale folds and faults—kink bands, conjugate faults, box folds, etc. The most important first-order surface is the décollement surface. This surface limits the glaciotectonic complex at its base and controls the extent of glaciotectonic disturbances. Below this surface, ordinary flat lying planar bedding occurs, whereas above the surface a number of structures are present characteristic of second- to fourth-order elements in the glaciotectonic architecture. The other first-order surface is the topographic top of the glaciotectonic complex, which eventually may be replaced by a truncating unconformity.

Tectonic triggering of slump sheets in the Upper Cretaceous carbonate succession of the Porto Selvaggio area (Salento peninsula, southern Italy): Synsedimentary tectonics in the Apulian Carbonate Platform

Soft-sediment deformation structures crop out in the Upper Cretaceous carbonate succession in Porto Selvaggio cove in the western Salento peninsula, Apulian foreland, southern Italy. The deformed interval is about 13m thick and occurs between shallow-water limestones and dolostones formed in peritidal and shallow subtidal environments. It comprises well-bedded grey mudstones interlayered with dark grey laminated microbioclastic wackestones characterized by couplets of closely spaced dark and bright laminae marked by the parallel orientation of calcareous microbioclasts and thin-shelled bivalves. The low biological diversity, scarcity of burrowing biota, and presence of a well preserved fish fauna provide evidence of anoxic conditions occurring in morphological depressions within the platform, and a stagnant, stratified water body affected by weak bottom currents, indicating the sudden development of a localised and short-lived intraplatform basin. Two soft-sediment deformation horizons (slump sheets) separated by undeformed limestones with similar facies occur in this part of the succession. The lower, thicker slump sheet (1.0–1.3m thick) contains asymmetric and box folds. Well-developed décollement surfaces (locally containing thick brecciated zones) cut the folds, forming small-scale thrust-sheets and indicating mixed plastic to brittle behaviour. The upper, thinner slump sheet (0.25–0.35m thick) contains only asymmetric folds, indicating plastic behaviour only. The differences in deformation style are attributed to differences in facies. Measurements of fold-axis orientations in the slump sheets show that they moved in similar directions, recording the development of a local, gently dipping palaeoslope. Autogenic (internal) trigger mechanisms are ruled out by a detailed consideration of facies. The slump sheets were triggered by allogenic, tectonic effects, either the weakening of sediment by seismic activity or the tectonically induced steepening of slopes, or a combination of both. Tectonically induced steepening is consistent with localised and sudden vertical facies changes related to the creation of an intraplatform basin. The occurrence of slump sheets in carbonate platform successions is unusual since carbonate platforms are normally associated with shelves or low-angle ramps.

Numerical investigation of deformation mechanics in fold‐and‐thrust belts: Influence of rheology of single and multiple décollements

Thin‐skinned fold‐and‐thrust belts related to convergence tectonics develop by scraping off a rock sequence along a weaker basal décollement often formed by water‐saturated shale layers or low‐viscosity salt horizons. A two‐dimensional finite element model with a viscoelastoplastic rheology is used to investigate the structural evolution of fold‐and‐thrust belts overlying different types of décollements. In addition, the influence of multiple weak layers in the stratigraphic column is studied. Model shale décollements are frictional, with lower friction angles as the cover sequence. Model salt layers behave linear viscous, due to a lower viscosity as the cover sequence, or with a power law rheology. Single viscous décollement simulations have been compared to an analytical solution concerning faulting versus folding. Results show that fold‐and‐thrust belts with a single frictional basal décollement generate thrust systems ramping from the décollement to the surface. Spacing between thrust ramps depends on the thickness of the cover sequence. The structural evolution of simulations with an additional low‐frictional layer depends on the strength relationship between the basal and the intersequential décollement. Tectonic underplating and antiformal stacking occur if the within‐sequence décollement is weaker. In the frontal part of models, deformation is restricted to the upper part and imbrication occurs with a wavelength depending on the depth of the intermediate weak layer. “Salt” décollement with a viscosity of 1018 Pa⋅s leads to isolated box folds (detachment folds). Multiple salt layers (1018 Pa⋅s) result in long‐wavelength folding. Our results for both frictional and viscous décollements are in bulk agreement with the Mohr‐Coulomb type, critical wedge theory.

Structural evolution of the northwestern Zagros, Kurdistan Region, Iraq: Implications on oil migration

ABSTRACT The studied area in Kurdistan Region of Iraq lies across an important topographic/structural boundary between the southern lowlands and the northern, folded and imbricated Zagros Mountains. It also encompasses a prominent change in structural orientation of the northern Zagros, from a general NW-SE “Zagros” to an E-W “Taurus” trend. Geological mapping and structural observations, both in the mountains (Mesozoic–Palaeogene) and in the lowlands (Neogene), led to the following conclusions. (1) The oldest recorded deformation is a layer-parallel shortening, coupled with southwest-vergent shear that was followed by major folding of ca. 10 km wavelength and ca. 1,000 m amplitude. Even the Upper Miocene–Pliocene Bakhtiari Formation has steep to overturned beds in some parts, and synclines preserve syn-tectonic strata of Neogene–Pliocene age. Box folding is associated with crestal collapse, internal thrusting in the core and with formation of systematic joint sets. (2) On the southern limb of the major folds, thrusting of variable offset can be observed. The thrusts on the southern and northern limbs are considered responsible for the major uplift during main folding. (3) En-échelon fold-relay patterns suggest left-lateral shear along the EW-oriented segment and right-lateral shear along the NW-oriented segment. (4) A quick-look qualitative analysis of striated fault planes suggests a variable shortening trend from NE-SW to N-S, and some rare NW-SE shortening all associated with thrust faults. (5) The general structural setting of the area is linked to the north-eastwards to northwards propagation of the Arabian Margin beneath Eurasia. The ca. 30° bend in the mountain chain may be explained by the original shape of the Arabian Margin, or by pre-existing tectonic zones of E-W orientation in the northern part. Several observations suggest that there was no oroclinal bending (i.e. major rotation) of different parts of the chain, but the structures simply molded on their local buttress (almost) according to present orientations. However, a limited amount of rigid-body rotation in the different segments cannot be ruled out. The changing shortening directions generated several structural combinations on both the NW-SE Zagros and the E-W Taurus segments of the arc, many of which are still preserved. (6) Spectacular bitumen seepage in Upper Cretaceous and Palaeocene limestone originates from fractures or geodes of these formations. Many of these bitumen-filled voids are linked to the above-described Late Neogene–Recent shortening-folding process; therefore hydrocarbon migration into these voids is interpreted to be very young. This contradicts earlier ideas about massive Late Cretaceous breaching and bleeding off of hydrocarbons in this region.

Opposite vergent synclines on the flanks of a large-scale box fold in the Chamba–Lahaul region, northwest Himalaya, India

This article focuses on two regional-scale synclines of the Chamba Thrust Sheet, northwest Himalaya. These synclines were explained by two different tectonic events. Earlier studies ascribe the NE vergent Tandi syncline and the SW vergent Chamba syncline to the older NE-directed nappe stacking and the younger SW-directed Himalayan deformation events, respectively. The new field data and structural analysis reveal that these synclines define the flanks of a large-scale asymmetric box fold referred to here as the Hadsar–Chobia box fold and to a common phase of deformation. The box fold in the Chamba Thrust Sheet has developed over a ductile–brittle substrate referred to here as the Chamba Thrust. This thrust has translated a portion of the Tethys Himalaya over both the Higher Himalayan Crystallines and the Lesser Himalaya. Structural analysis, particularly the parallelism between the trends of hinge lines of the Hadsar–Chobia box fold and the strike of the regional thrust planes indicate that the folding and translation may have occurred simultaneously during the D1 deformation episode.

The retroviral cyclin of walleye dermal sarcoma virus binds cyclin-dependent kinases 3 and 8

Walleye dermal sarcoma virus encodes a retroviral cyclin (rv-cyclin) with a cyclin box fold and transcription activation domain (AD). Co-immune precipitation (co-IP) identified an association of rv-cyclin with cyclin-dependent kinase 8 (cdk8). Cdk8 is dependent upon cyclin C and regulates transcription with the Mediator complex, a co-activator of transcription. Mutation of cyclin residues, required for cdk binding, disrupts rv-cyclin–cdk8 co-IP. Mutation or removal of the AD has no effect on cdk8 interaction. Direct rv-cyclin–cdk8 binding is demonstrated by pulldown of active cdk8 and by GST-rv-cyclin binding to recombinant cdk8. Cdk3 is also activated by cyclin C and phosphorylates retinoblastoma protein to initiate entry into the cell division cycle. Co-IP and pulldowns demonstrate direct rv-cyclin binding to cdk3 as well. The rv-cyclin functions as a structural ortholog of cyclin C in spite of its limited amino acid sequence identity with C cyclins or with any known cyclins.

Analysis of complete fold shape based on quadratic Bézier curves

Six segments of quadratic Bézier curve are joined together according to some geometrical rules to approximate fold shape. In a classification of folds based on this method, an ideal fold shape is determined by two parameters. The first one, u c , termed the axial lift-up ratio of the central part, generates the folds within a broad spectrum of forms ranging from box folds to chevron folds. The other one, γ, is the interlimb angle. In the quantitative description of complete folds with multiple layers, three new parameters, θ, T and E are used to describe the deflection angle of the axial plane, the thickness increment of hinge zone and the limb elongation, respectively. Based on the modeling method, the program “Bézier Fold Profiler” has been developed, with which most types of folds can be simulated by varying thirteen parameters. Two description methods, complete fold description and individual layer description, can be used for the quantitative analysis of folds. The description methods are carried out by the visual matching of the fold profile displayed on-screen from an imported digital image. The layer curves of the model are displayed on the fold image. This method has the advantage of speed and simplicity.