Femoral neck fracture following intramedullary nailing with misplacement of an end cup: report of two cases

Femoral neck fracture is an unusual complication of intramedullary fixation of a broken femur. We report on two cases of femoral neck fractures attributed to misplacement of an end cup and subsequent invasive maneuvers in an effort to remove it. Iatrogenic fractures of the femoral neck during or after intramedullary nailing are reported in the medical literature. Authors associate it with many possible technical mistakes performed during the procedure, yet no complications after missed end cup placement were noted. We suggest that the fractures described below were a consequence of injury to the vascular supply and bone stock of the initially intact femoral neck

Keratin and S100 calcium-binding proteins are major constituents of the bovine teat canal lining

The bovine teat canal provides the first-line of defence against pathogenic bacteria infecting the mammary gland, yet the protein composition and host-defence functionality of the teat canal lining (TCL) are not well characterised. In this study, TCL collected from six healthy lactating dairy cows was subjected to two-dimensional electrophoresis (2-DE) and mass spectrometry. The abundance and location of selected identified proteins were determined by western blotting and fluorescence immunohistochemistry. The variability of abundance among individual cows was also investigated. Two dominant clusters of proteins were detected in the TCL, comprising members of the keratin and S100 families of proteins. The S100 proteins were localised to the teat canal keratinocytes and were particularly predominant in the cornified outermost layer of the teat canal epithelium. Significant between-animal variation in the abundance of the S100 proteins in the TCL was demonstrated. Four of the six identified S100 proteins have been reported to have antimicrobial activity, suggesting that the TCL has additional functionality beyond being a physical barrier to invading microorganisms. These findings provide new insights into understanding host-defence of the teat canal and resistance of cows to mastitis

Numeric simulations of surface pressure and microslip phenomena occurring in riveted joints of semi-monococque structures in effect of the action of tension field

Tension fields are shown to have an influence on surface pressure and on material deformation in the riveted joints in thin walled structures and particularly in semistressed skin structures. Stresses and materials displacements were analyzed in the riveted joints performing under such conditions. Special attention has been attached to estimation of the microslips occurring between rivets and holes. A thin plate panel has been used for the test sample, which under effort condition revealed tension fields

Digital Materials – Evaluation of the Possibilities of using Selected Hyperelastic Models to Describe Constitutive Relations

The authors tried to identify the parameters of numerical models of digital materials, which are a kind of composite resulting from the manufacture of the product in 3D printers. With the arrangement of several heads of the printer, the new material can result from mixing of materials with radically different properties, during the process of producing single layer of the product. The new material has properties dependent on the base materials properties and their proportions. Digital materials tensile characteristics are often non-linear and qualify to be described by hyperelastic materials models. The identification was conducted based on the results of tensile tests models, its various degrees coefficients of the polynomials to various degrees coefficients of the polynomials. The Drucker’s stability criterion was also examined. Fourteen different materials were analyzed

Wpływ systemu uprawy i odchwaszczania na plon i jakość włókna lnianego

Fibrous flax, despite its many different uses, is currently growing within a relatively small area, mainly because of the low production margin. This study shows possible approaches to the reduce production costs of flax fibre by 424 PLN per hectare as a result of no-tillage cultivation and direct sowing. No such research on flax fibre production has been conducted so far. The study (carried in 2011-2012) covered highly differentiated temperature and precipitation conditions. The yields of homomorphic fibre in a dry year were higher than in a year with optimum precipitation in the no-till system comparing to conventional tillage. The application of Chisel 75WG increased the yield of fibre regardless of the weather and cultivation system and was the result of both straw yield and fibre content increase. Tillage systems and herbicides differentiated the length and linear density of homomorphic fibre and impurity content, whereas the elongation at break and tenacity did not depend on the cultivation method.Len włóknisty mimo wielostronnych walorów użytkowych jest aktualnie uprawiany w Polsce na niewielkiej powierzchni. Wynika to z małej opłacalności jego produkcji. Omawiana praca wskazuje na możliwość obniżenia kosztów produkcji włókna lnianego oraz określa wpływ systemów uprawy i odchwaszczania na jego jakość. Obniżenie kosztów produkcji włókna upatruje się w zaniechaniu najbardziej energo i czasochłonnego zabiegu jakim jest orka i stosowanie systemów bezpośrednich, zwalczenie chwastów oraz zamianę przerobu słomy metodą mniej kosztowną z wytwarzaniem włókna jednopostaciowego zamiast dwupostaciowego. Dotychczas nie prowadzono takich badań przy produkcji włókna lnianego. Omawiane badania prowadzono w latach 2011-2012 przy dużym zróżnicowaniu przebiegu temperatury i opadów co pozwalało określić interakcję przebiegu pogody z czynnikami badawczymi na plon włókna. Plony włókna jednopostaciowego w roku suchym były wyższe a w roku o optymalnych opadach niższe w uprawie bezorkowej niż tradycyjnej. Stosowanie herbicydu Chisel 75W9 niezależnie od wysokości opadów i sposobu uprawy przyczyniło się do wzrostu plonu włókna. Wzrost ten wynikał zarówno ze wzrostu plonu słomy jak i procentowej zawartości włókna. Systemy uprawy oraz herbicydy różnicowały długość, masę liniową i podzielność włókna jednopostaciowego oraz jego zanieczyszczenie

The EOG event recognition method in an EEG signal towards SSVEP BCI improvement

This paper presents a method of recognizing EOG artifacts in an EEG signal. Moreover, it shows the possibility of determining the direction of eye movement. The idea behind this method is to develop a hybrid brain-computer interface relying on SSVEP phenomena and EOG artifacts acquired from the EEG signal. Recognition of an EOG event and its direction can be used to improve the SSVEP detection accuracy, overall system responsiveness, and increase the information transfer rate (ITR). Eye movement direction is recognized using a decision tree and histogram-based features calculated from EEG signals recorded in Fp1-O1 and Fp2-O2 points. The accuracy of 75% was achieved for a group of 8 subjects, while the average precision of detecting movement direction in horizontal plane was 78%

Selected problems concerning the analysis of thin-walled structures with the use of finite element method

The aim of the paper was presentation and comparison of numerical methods applied in thin-walled structures analysis, with special attention paid to possibility of usage the Finite Element Method (FEM), especially in nonlinear analysis. There were presented basic differences between classical approach to modelling and analyzing thin-walled structures, and these performed with FEM methods using. The biggest emphasis was placed on the analysis of semimonocoąues, in which the loss in the shell 's stability is possible in the range of operational load activity. According to this, many nonlinear terms like global and local buckling, contact problems, significant deformations and shifts, are present. Worth emphasizing is the fact, that tension field, is something that was described long time ago. First paper s about this phenomenon were published in the last century. Although it is a common effect that takes place in semimonocoques, there are not many publications that analyze and examine this phenomenon. In this paper, an analysis of two-sided, thin-walled spar, which has undergone the flexion by the shearing force in the plane of the panel, was presented. The spar was designed as a classic semimonocoque, in which load transmission function is separated. It was assumed that, for the sake of small thickness, shell elements transmit mainly tangential loads, normal loads, when normal loads are transmitted by framework elements. Riveted joints are used to join elements of framework and shell. There are presented and compared results of analysis for models with various complexities. Firstly, results of analysis of classical model of semimonocoques were presented. It means that framework elements were modelled as rod elements transmitted only normal loads, but shell elements were modelled as disc semimonocoque elements, in this case transmitted only tangential loads. Area of section of rod elements was adequately increased, in order to consideration mating width, coming from partial transmission of normal loads by the shell elements. Results obtained for intermediate models were also presented, as well as for complex shell model, which allows on advanced nonlinear analysis of tension field, which consider contact between framework and shell elements. Applications of formulated models to thin-walled structure, especially aircraft ones and further possibilities of presented method of analysis were discussed