Nanoselluloosan ja –ligniinin välisten vuorovaikutusten tutkiminen hyödyntäen mekaanis-entsymaattisesti tuotettuja selluloosananofibrillejä

Recently the development of wood-based materials has been a trending topic due to raised environmental consciousness. This new way of thinking has opened new markets and competition towards finding environmentally friendly alternatives to petroleum based products. VTT has developed a high consistency and simple method to produce cellulose nanofibrils (CNF) referred to as “HefCel”, which is based on enzyme-assisted mechanical production of nanofibrillar cellulose. Herein HefCel and its interaction with colloidal lignin particles (CLPs) was studied by preparing nanocomposite films in order to obtain enhanced fundamental knowledge of their compatibility. Two different film preparation methods were applied in order to distinguish whether the production technique has an effect on the properties of the nanocomposite films. Moreover, treatment of the films with the enzyme laccase was used in an attempt to form crosslinks between lignin constituents and to evaluate possible changes in film properties. Produced nanocomposite films were characterized by electron microscopy (SEM, TEM), dry and wet tensile testing, and water contact angle (WCA) measurements. It was discovered that the preparation method had an influence on the properties of the nanocomposite films. Tensile stress at break and WCA values between ambient dried and filtered nanocomposite films ranged between ca. 19–56 MPa and 27–58o, respectively. Ambient dried nanocomposite films exhibited higher tensile properties compared to filtered nanocomposite films. Moreover, the ambient dried films showed generally higher WCA values exhibiting also stronger correlation to the lignin content compared to those of the nanocomposite films prepared with the filtration method. Finally, laccase experiment did not have a significant effect on tensile properties, however higher WCA values were discovered.Puupohjaiset materiaalit ovat saaneet viime aikoina paljon huomiota ympäristöystävällisinä vaihtoehtoina öljypohjaisten materiaalien korvaamiseksi. Tämän tutkimuksen tavoitteena oli saada perusteellista ymmärrystä VTT:n kehittämän entsyymiavusteisesti tuotetun nanoselluloosan (HefCel) ja kolloidisten ligniinipartikkelien välisistä vuorovaikutuksista valmistamalla ohuita nanokomposiittifilmejä paineistetulla suodatuksella ja valumenetelmällä, jossa veden annettiin haihtua normaaliolosuhteissa. Työssä tutkittiin myös erilaisten valmistusmenetelmien vaikutusta nanofilmien ominaisuuksiin. Lisäksi tutkittiin, vaikuttaako jäännösligniiniä sisältävien HefCel-filmien käsittely lakkaasi-entsyymillä filmien ominaisuuksiin. Nanokomposiittifilmejä karakterisoitiin elektronimikroskopiamenetelmillä (SEM, TEM), vetolujuusmittauksilla sekä mittaamalla veden kontaktikulma filmien pinnalla. Tulokset osoittivat valmistusmenetelmien vaikuttavan nanokomposiittien ominaisuuksiin. Vetolujuusarvot vaihtelivat 19–56 MPa, kun taas vesikontaktikulmat vaihtelivat 27–58o valmistusmenetelmästä riippuen. Valumenetelmällä valmistettujen filmien vetolujuus- ja vesikontaktikulmalukemat olivat yleisesti korkeammat verrattuna suodatusmenetelmällä valmistettujen filmien arvoihin. Lakkaasikäsittely johti korkeampiin filmien kontaktikulma-arvoihin, mutta lujuusominaisuuksiin sillä ei ollut merkittävää vaikutusta

The role of short latency reflexes in the motor control of quadriceps in humans

A total of 34 volunteer subjects participated in a series of experiments. These experiments were designed to investigate the characteristics and functional role of an excitatory reflex pathway linking the pretibial muscles to quadriceps (CPQ reflex). The CPQ reflex was evoked by low intensity electrical stimulation of common peroneal nerve (CPN) at the level of caput fibulae. The reflex was observed in averaged EMG of rectus femoris (RF) and vastus medialis (VM). Voluntary contraction of Q was needed to reveal the reflex and no responses were detected in the recordings from relaxed muscle. The peak to peak amplitude and area of the responses were measured in non-rectified and rectified averaged EMG. The stability of the CPQ reflex was investigated in the first series of experiments. Nine trials were distributed across three sessions with the perceptive caution to keep the stimulating and recording conditions similar. A constant contraction (20% of maximum voluntary contraction) in quadriceps was maintained by the subjects during the tests. Constant stimulus intensity to evoke maximum reflex was applied in all trials. The result suggested that the peak- peak amplitude and the threshold of the CPQ reflex was extremely consistent with-in session and between sessions of the experiment. Graded stimulus intensities between 0.9 and 1.5xmotor threshold (MT) in tibialis anterior (TA) were applied to CPN in the second series of experiments while the quadriceps (Q) was contracted at a level of 20% of maximum voluntary contraction (MVC). The electrical stimulation of the CPN evoked excitatory responses in all the subjects with a latency of about 30+/-2.1ms (mean +/- ISD). The responses were regarded significant with amplitude beyond 2 standard deviation (SD) of the mean. The mean was calculated from 30ms pre-stimulus averaged EMG. In three subjects making contractions at 20% of MVC significant CPQ reflexes were recorded with stimulation at an intensity of 0.9xMT. The extrapolation of the pooled data also suggests an electrical threshold of around O.8xMT. This low threshold and the short latency strongly suggest the participation of group I afferent types in this reflex pathway. Maximum response was evoked by stimulus intensity of about 1.3XMT. The changes in the reflex magnitude in different knee and hip joint positions were also investigated in another series of experiments. The knee positioning was shown to affect the reflex amplitude in all subjects. The reflex became smaller towards more flexed position of the knee joint. Two patterns of reaction were recognised among the subjects. One group showed a very significant and abrupt reduction in the magnitude of the reflex after 1

ReShader: View-Dependent Highlights for Single Image View-Synthesis

In recent years, novel view synthesis from a single image has seen significant progress thanks to the rapid advancements in 3D scene representation and image inpainting techniques. While the current approaches are able to synthesize geometrically consistent novel views, they often do not handle the view-dependent effects properly. Specifically, the highlights in their synthesized images usually appear to be glued to the surfaces, making the novel views unrealistic. To address this major problem, we make a key observation that the process of synthesizing novel views requires changing the shading of the pixels based on the novel camera, and moving them to appropriate locations. Therefore, we propose to split the view synthesis process into two independent tasks of pixel reshading and relocation. During the reshading process, we take the single image as the input and adjust its shading based on the novel camera. This reshaded image is then used as the input to an existing view synthesis method to relocate the pixels and produce the final novel view image. We propose to use a neural network to perform reshading and generate a large set of synthetic input-reshaded pairs to train our network. We demonstrate that our approach produces plausible novel view images with realistic moving highlights on a variety of real world scenes.Comment: SIGGRAPH Asia 2023. Project page at https://people.engr.tamu.edu/nimak/Papers/SIGAsia2023_Reshader/index.html and video at https://www.youtube.com/watch?v=XW-tl48D3O

The effect of Hand Positions on the Vibration Platform on Shoulder Muscle: Strength and Proprioception

Introduction: To compare the short-term effect of one session of Whole Body Vibration (WBV) in two positions of hand on the vibration platform on isokinetic strength of Rotator cuff and shoulder proprioception. Method and Materials: A total of 60 young healthy students participated in the present study completing three positions of control (no vibration), push up with straight elbow, and push up with semi flexed elbow (two vibration positions) running for two minutes with 30-minute rest between the positions. After control position, vibration positions were tested randomly on the Power Plate device (F: 30Hz and low amp). The isokinetic strength of Rotator Cuff and the absolute angular error in joint repositioning test in 3 target angles of 0°, 45°, and 90° were measured using Kin-Com dynamometer before and after each position. Then, the results of the three positions were compared together. Results: Despite decrease in dynamic strength of medial rotators after three positions, this decrease was observed to be significantly less in push up with straight elbow compared with that in control position (P=0.03). Also, there was a significant difference in Concentric MPT of Lateral Rotators between the three positions with control position revealing the greatest decline in lateral rotators strength (P=0.01) and push up with straight elbow was found to be more effective than semi flexed elbow (P=0.03). Moreover, There was a significant improvement in angle repositioning for the three positions; however, it was considerably more only in zero degree in the push up with semi flexed elbow position as compared with that in the control position (P=0.03). No significant changes were found between push up with straight elbow and semi flexed elbow positions, either. Conclusions: The two different hand positions did not alter the effect of vibration on neuromuscular system in young and healthy individuals. Although a single session of WBV had a positive effect on the neuromuscular system of the young healthy participants, the two positioning did not make a significant difference.Key words: Whole body vibration training, shoulder muscle strength, proprioceptio

Comparison of Vertical Ground Reaction Force during Walking in Patients with Sacroiliac Joint Pain and Healthy People

Introduction: Vast majority of the muscular disorders are known to be related to Sacroiliac joint. Due to the main role played by Sacroiliac joint, the current study was conducted to examine the effect of the pain among the people suffering from Sacroiliac joint pain on the vertical ground reaction force parameter. Materials and Methods: This case control study was carried out on 19 participants with Sacroiliac joint pain, VAS 3-5 and average age of 27±5.7, and 19 subjects with normal health conditions and average age of 29±7.6. The relevant data were collected while the participants were asked to walk at their desired speed over the force plate located on their way. Later on, all the parameters of vertical ground reaction force in the stance phase were recorded. At the end, data collected were compared by independent T-test in SPSS. Results: The results of the study revealed that participants distributed in control (healthy individuals) and experimental (individuals with Sacroiliac joint pain) groups were significantly different regarding the parameters of time and speed required to reach the stage of weight transition to the heel. Discussion: Considering the findings, it can be concluded that some compensatory strategies were adopted by the individuals with Sacroiliac joint- related problems in order to decrease the force that body experienced during walking.Key words: Force Plate, Sacroiliac Joint, Vertical Ground Reaction Forc

Pedobarography of the coper and non-coper ACL-deficient knee subjects during single and double leg stance

Introduction: Biomechanical studies have frequently shown a close relationship between the knee and ankle joint movements. ACL-deficiency may change the foot pressure pattern of the ACL-deficient knee subjects. The current study aimed to investigate the pattern of the foot pressure in coper and non-coper ACL-deficient knee subjects during standing on one and both feet. Methods and Materials: This case-control study was conducted on 12 coper and 12 non-coper ACL-deficient knee subjects and 25 age-sex matched healthy subjects. The subjects were tested barefoot during single and bilateral standing on the platform of a Zebris pedobarograph tool. The outcome measures included the measurements of the pressures of each part of the foot during the tests. Results: The results showed a significantly decreased total pressure only between the non-coper and control groups during double leg stance test. In terms of the forefoot pressure, a significant increased pressure was shown only in the non-coper ACL-deficient knee subjects during both single and double leg stance tests (P<0.05). In both test conditions, the coper ACL-deficient knee subjects showed forefoot and hind foot pressures very close to the control group (P>0.05). Conclusion: This study revealed marked changes following ACL-deficiency mainlyin non-coper ACL-deficient knee subjects. The increased forefoot pressure in non-coper ACL-deficient knee subjects was probably due to the forwarded line of gravity in these patients aligned with their base of support to keep their knees more stable. Further studies are needed to verify the differences between the male and female ACL-deficient knee subjects.Keywords: Coper/non-coper ACL-deficient knee subjects; Stability; Pedobarograph; Foot pressure system; Postural contro