INVESTIGATION OF THE MOMENT OF INERTIA AND THE BIOMECHNICAL INTERNAL FORCES ACTING ON THE KNEE DURING HIKING

The purpose of this study is to use three-dimensional (3D) motion capture data together with the computer software for analysis of the human body, Anybody Technology1, to perform inverse dynamics and quantify the biomechanical internal forces acting on the knee joints, particularly, the tibiofemoral and patellofemoral. The experiment will be conducted on-land, within a controlled environment. A customized hiking bench, designed and constructed to be identical to the deck of a Laser Standard dinghy will be used to simulate sailing conditions. From the results analysis, we can address deficiencies in the sailing techniques of sailors thereby minimizing the occurrence of knee injury during sailing. We have also investigate on the moment of inertia generated by the human body during the hiking action to explore the most effective sailing posture to be adopted

A STUDY OF MUSCLE FATIGUE FOR PROLONGED STANDING USING SURFACE ELECTROMYOGRAM: A CASE STUDY

The purpose of this study is to use surface Electromyogram (sEMG) for the investigation of muscle activities in the lower limbs of human subjects during prolonged standing. It has been suggested that prolonged standing leads to muscle fatigue. This is a single-subject investigation that involves a healthy female subject, performing 8 similar quiet standing trials for one hour on separate days. sEMG methods were used to record myoelectric activity from the Tibialis Anterior (TA), Peroneus Longus (PE) and Gastrocnemius muscles (GA). In the preliminary analysis, a progressive decrease in the median frequency curve has been observed in all muscle groups investigated and the trend was statistically significant (p < 0.05). The results of this study confirmed that muscle fatigue sets in during prolonged standing

A Positive Feedback Loop Between Myc and Aerobic Glycolysis Sustains Tumor Growth in a Drosophila Tumor Model

Cancer cells usually exhibit aberrant cell signaling and metabolic reprogramming. However, mechanisms of crosstalk between these processes remain elusive. Here, we show that in an in vivo tumor model expressing oncogenic Drosophila Homeodomain-interacting protein kinase (Hipk), tumor cells display elevated aerobic glycolysis. Mechanistically, elevated Hipk drives transcriptional upregulation of Drosophila Myc (dMyc; MYC in vertebrates) likely through convergence of multiple perturbed signaling cascades. dMyc induces robust expression of pfk2 (encoding 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase; PFKFB in vertebrates) among other glycolytic genes. Pfk2 catalyzes the synthesis of fructose-2,6-bisphosphate, which acts as a potent allosteric activator of Phosphofructokinase (Pfk) and thus stimulates glycolysis. Pfk2 and Pfk in turn are required to sustain dMyc protein accumulation post-transcriptionally, establishing a positive feedback loop. Disruption of the loop abrogates tumorous growth. Together, our study demonstrates a reciprocal stimulation of Myc and aerobic glycolysis and identifies the Pfk2-Pfk governed committed step of glycolysis as a metabolic vulnerability during tumorigenesis

INVESTIGATION OF ELECTROMYOGRAPHY OF MAJOR MUSCLE GROUPS WHILE HIKING OUT DURING SAILING ON BOTH LAND AND WATER

The purpose of this study is to compare the Electromyographic (EMG) readings of muscle activation while hiking out on both land and water. This preliminary study aims to determine if there is a significant difference between EMG readings conducted in laboratory conditions as well as on water when the subject is hiking out while sailing. Muscle groups tested in this study were the Rectus Femoris, Vastus Laterialis and the Tibialis Anterior. EMG readings were taken and expressed as a percentage of the maximal voluntary contraction (MVC) baseline from the subject. The preliminary results of this study show that the RF muscles contribute more to hiking out than the VL muscles in the laboratory and at sea

System Integration - A Major Step toward Lab on a Chip

Microfluidics holds great promise to revolutionize various areas of biological engineering, such as single cell analysis, environmental monitoring, regenerative medicine, and point-of-care diagnostics. Despite the fact that intensive efforts have been devoted into the field in the past decades, microfluidics has not yet been adopted widely. It is increasingly realized that an effective system integration strategy that is low cost and broadly applicable to various biological engineering situations is required to fully realize the potential of microfluidics. In this article, we review several promising system integration approaches for microfluidics and discuss their advantages, limitations, and applications. Future advancements of these microfluidic strategies will lead toward translational lab-on-a-chip systems for a wide spectrum of biological engineering applications

Preceding human metapneumovirus infection increases adherence of Streptococcus pneumoniae and severity of murine pneumococcal pneumonia

BackgroundCoinfection with respiratory virus and Streptococcus pneumoniae has been frequently reported in several epidemiologic studies. The aim of this study was to explore the effect of preceding human metapneumovirus (hMPV) inoculation on subsequent pneumococcal infection.MethodsHep-2 and A549 cells were infected with hMPV then inoculated with S. pneumoniae. Bacterial adhesion was measured using colony forming unit and cytometric-fluorescence assays. In vivo bacterial adhesion was examined in hMPV-infected mice after inoculation of fluorescence-conjugated S. pneumoniae. Pulmonary inflammation (bacterial titers, cytokine levels, and histopathology) of hMPV-infected mice was investigated after inoculation with S. pneumoniae.ResultsIn vitro results of bacterial infection with S. pneumoniae on A549 and Hep-2 monolayer cells showed that even though cellular adherence was variable among different serotypes, there was significantly enhanced bacterial adherence in A549 cells with preceding hMPV infection. In addition, in vivo study of hMPV-infected mice showed increased adhesion of S. pneumoniae on the bronchial epithelium with delayed bacterial clearance and exacerbated histopathology. Furthermore, mice with preceding hMPV infection showed repressed recruitment of airway neutrophils with decreased expression of neutrophil chemoattractants during pneumococcal infection.ConclusionThese results suggest that hMPV-infected airway cells, especially the lower airway epithelium, express increased adherence with S. pneumoniae. Furthermore, hMPV-infected mice showed impaired recruitment of airway neutrophils, possibly leading to delayed bacterial clearance and exacerbated pulmonary inflammation, after secondary infection with pneumococcal isolates

Tunable photonic Bloch oscillations in electrically modulated photonic crystals

We exploit theoretically the occurrence and tunability of photonic Bloch oscillations (PBOs) in one-dimensional photonic crystals (PCs) containing nonlinear composites. Because of the enhanced third-order nonlinearity (Kerr type nonlinearity) of composites, photons undergo oscillations inside tilted photonic bands, which are achieved by the application of graded external pump electric fields on such PCs, varying along the direction perpendicular to the surface of layers. The tunability of PBOs (including amplitude and period) is readily achieved by changing the field gradient. With an appropriate graded pump AC or DC electric field, terahertz PBOs can appear and cover a terahertz band in electromagnetic spectrum

The crystal structure of the DNase domain of colicin E7 in complex with its inhibitor Im7 protein

AbstractBackground: Colicin E7 (ColE7) is one of the bacterial toxins classified as a DNase-type E-group colicin. The cytotoxic activity of a colicin in a colicin-producing cell can be counteracted by binding of the colicin to a highly specific immunity protein. This biological event is a good model system for the investigation of protein recognition.Results: The crystal structure of a one-to-one complex between the DNase domain of colicin E7 and its cognate immunity protein Im7 has been determined at 2.3 Å resolution. Im7 in the complex is a varied four-helix bundle that is identical to the structure previously determined for uncomplexed Im7. The structure of the DNase domain of ColE7 displays a novel α/β fold and contains a Zn2+ ion bound to three histidine residues and one water molecule in a distorted tetrahedron geometry. Im7 has a V-shaped structure, extending two arms to clamp the DNase domain of ColE7. One arm (α1∗–loop12–α2∗; where ∗ represents helices in Im7) is located in the region that displays the greatest sequence variation among members of the immunity proteins in the same subfamily. This arm mainly uses acidic sidechains to interact with the basic sidechains in the DNase domain of ColE7. The other arm (loop 23–α3∗–loop 34) is more conserved and it interacts not only with the sidechain but also with the mainchain atoms of the DNase domain of ColE7.Conclusions: The protein interfaces between the DNase domain of ColE7 and Im7 are charge-complementary and charge interactions contribute significantly to the tight and specific binding between the two proteins. The more variable arm in Im7 dominates the binding specificity of the immunity protein to its cognate colicin. Biological and structural data suggest that the DNase active site for ColE7 is probably near the metal-binding site

Viscoelastic behaviour of human mesenchymal stem cells

<p>Abstract</p> <p>Background</p> <p>In this study, we have investigated the viscoelastic behaviour of individual human adult bone marrow-derived mesenchymal stem cells (hMSCs) and the role of F-actin filaments in maintaining these properties, using micropipette aspiration technique together with a standard linear viscoelastic solid model.</p> <p>Results</p> <p>Under a room temperature of 20°C, the instantaneous and equilibrium Young's modulus, <it>E</it>₀and <it>E</it>_∞, were found to be 886 ± 289 Pa and 372 ± 125 Pa, respectively, while the apparent viscosity, <it>μ</it>, was 2710 ± 1630 Pa·s. hMSCs treated with cytochalasin D up to 20 μM at 20°C registered significant drop of up to 84% in stiffness and increase of up to 255% in viscosity. At the physiological temperature of 37°C, <it>E</it>₀and <it>E</it>_∞have decreased by 42–66% whereas <it>μ </it>has increased by 95%, compared to the control. Majority of the hMSCs behave as viscoelastic solid with a rapid initial increase in aspiration length and it gradually levels out with time. Three other types of non-typical viscoelastic behavior of hMSCs were also seen.</p> <p>Conclusion</p> <p>hMSCs behave as viscoelastic solid. Its viscoelstic behaviour are dependent on the structural integrity of the F-actin filaments and temperature.</p