Evaluation and Correction for Optical Scattering Variations in Laser Speckle Rheology of Biological Fluids

Biological fluids fulfill key functionalities such as hydrating, protecting, and nourishing cells and tissues in various organ systems. They are capable of these versatile tasks owing to their distinct structural and viscoelastic properties. Characterizing the viscoelastic properties of bio-fluids is of pivotal importance for monitoring the development of certain pathologies as well as engineering synthetic replacements. Laser Speckle Rheology (LSR) is a novel optical technology that enables mechanical evaluation of tissue. In LSR, a coherent laser beam illuminates the tissue and temporal speckle intensity fluctuations are analyzed to evaluate mechanical properties. The rate of temporal speckle fluctuations is, however, influenced by both optical and mechanical properties of tissue. Therefore, in this paper, we develop and validate an approach to estimate and compensate for the contributions of light scattering to speckle dynamics and demonstrate the capability of LSR for the accurate extraction of viscoelastic moduli in phantom samples and biological fluids of varying optical and mechanical properties

Strategic planning for wood farming development (Case study: Urmia)

YesWood farming is one of the strategies of agricultural development programs to reform unsustainable exploitation of natural resources. Poplar is one of the known species for wood farming in the country. This species is fast-growing and has numerous Colognes has the ability to adapt to different climatic conditions. Fast growth, good economic returns and traditional agricultural knowledge, favorable habitat to agriculture are advantages of poplar for agricultural development. However, the result of previous studies indicates existing barriers to the development of plantation and its development need strategic planning. What seem essential today are strategies to overcome these obstacles. Accordingly, this present study with a holistic view trying to identify the strengths, weaknesses, opportunities and threats of poplar farming. And the most appropriate strategies for the development of poplar farming in Urmia have offered. This research was a Field study and conducted using questionnaires. In this study, strategies were defined using SWOT analysis and the strategies were prioritized using analysis network process. The results showed the history of poplar farming in this region is the most important benefit to development and the many uses for poplar wood is the next priority. Increasingly replacement of poplar farming with alternative cultures is one of the main weaknesses of poplar farming development in this region. After that long return of profitability in poplar farming is the second priority. The most important opportunities for the development were the development of credit specialists to support of poplar farming and the most important threat was lack of annual financing of farmers. Also the results of strategic prioritization showed, Modern irrigation methods to reduce water consumption and planning to teach correct principles of technical planting, farming and harvesting are considered as the most important strategies

Speckle-scale focusing in the diffusive regime with time reversal of variance-encoded light (TROVE)

Focusing of light in the diffusive regime inside scattering media has long been considered impossible. Recently, this limitation has been overcome with time reversal of ultrasound-encoded light (TRUE), but the resolution of this approach is fundamentally limited by the large number of optical modes within the ultrasound focus. Here, we introduce a new approach, time reversal of variance-encoded light (TROVE), which demixes these spatial modes by variance encoding to break the resolution barrier imposed by the ultrasound. By encoding individual spatial modes inside the scattering sample with unique variances, we effectively uncouple the system resolution from the size of the ultrasound focus. This enables us to demonstrate optical focusing and imaging with diffuse light at an unprecedented, speckle-scale lateral resolution of ~5 µm

Evaluating the Viscoelastic Properties of Tissue from Laser Speckle Fluctuations

Most pathological conditions such as atherosclerosis, cancer, neurodegenerative, and orthopedic disorders are accompanied with alterations in tissue viscoelasticity. Laser Speckle Rheology (LSR) is a novel optical technology that provides the invaluable potential for mechanical assessment of tissue in situ. In LSR, the specimen is illuminated with coherent light and the time constant of speckle fluctuations, τ, is measured using a high speed camera. Prior work indicates that τ is closely correlated with tissue microstructure and composition. Here, we investigate the relationship between LSR measurements of τ and sample mechanical properties defined by the viscoelastic modulus, G*. Phantoms and tissue samples over a broad range of viscoelastic properties are evaluated using LSR and conventional mechanical testing. Results demonstrate a strong correlation between τ and |G*| for both phantom (r = 0.79, p <0.0001) and tissue (r = 0.88, p<0.0001) specimens, establishing the unique capability of LSR in characterizing tissue viscoelasticity

Schematic of the LSR optical setup

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065014#pone.0065014-Hajjarian1" target="_blank">[12]</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065014#pone.0065014-Nadkarni2" target="_blank">[14]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065014#pone.0065014-Hajjarian2" target="_blank">[16]</a>. Light from a randomly polarized He-Ne laser (632 nm, 30 mW) is coupled into a single mode fiber (SMF600). The beam is polarized, collimated, and focused (focal length 25 cm, 50 µm spot size) at the sample surface. A beam-splitter is used to ensure speckle patterns are acquired at 180° back-scattering geometry. The cross-polarized component of back-scattered light is focused at the CMOS sensor of a high-speed camera (PL-761, Pixelink, Ontario, Canada), equipped with a focusing lens system (MLH-10×, Computar, Commack, NY). The acquired speckle frame series are transferred to a high-speed computer for further processing.</p

Prioritize of poplar wood processing industries in the Kurdistan province with the aim of poplar wood value chain upgrading

Wood industries need abundant resources of wooden raw material and these industries could continue to productive activities with poplar consumption attitudes. Given the size and importance of poplar farming and its role in the economy of Kurdistan, study for evaluation of its value chain is essential. Since improving of the poplar value chain is a factor for the development of poplar farming given the current situation in Kurdistan providence value chain, in this research suitable value chains was identified for development. According to the study objectives, the effective criteria to prioritize research alternatives were identified through library studies and with the help of questionnaires were completed and confirmed, according to the experts. The experts were used to identify the interrelations between criteria. After completing the paired comparison questionnaire, weight of each criterion was measured and priorities were found by the ANP. Ultimately, the final results of alternatives ranking showed the most weight is related to the MDF chain with weight of 0.259. The next priorities were paper, straw and cellulose with respectively weights of 0.135, 0.134 and 0.115. The next priorities were furniture, particle board, plywood and matches, pallets, boxes, lumber and boards, with weights of 0.096, 0.077, 0.075, 0.073 and 0.019 respectively. Results of group decision-making using ANP showed that in the current situation with regard to the suitable market for MDF, proper future demand, appropriate market for processed products from MDF, condition of infrastructure in Kordestan province and feasibility of use of poplar wood in production of MDF, this industry is more important to develop in Kordestan province

LSR results of |<i>G*(ω)</i>| for synovial fluid and vitreous humor measured with and without optical scattering correction.

<p>The red diamonds are the average |<i>G*(ω)</i>| moduli, of synovial fluid (panel (a)) and vitreous humor (panel (b)) samples of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065014#pone-0065014-g008" target="_blank">Fig. 8</a>, obtained from LSR by using the DWS expression (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065014#pone.0065014.e003" target="_blank">eqn. (3)</a>). The red error bars correspond to standard error values. The purple squares represent the average |<i>G*(ω)</i>| moduli, obtained from the corrected MSD values using <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065014#pone.0065014.e006" target="_blank">eqn. (6)</a>, and the purple error bars correspond to the standard errors. Also depicted in this figure are the |<i>G*(ω)</i>| values for the samples measured using a conventional rheometer (black solid line, round markers). While LSR results compensated for optical scattering show close correspondence with rheology measurements, the DWS-based approach results in an offset of about one decade relative to conventional testing results.</p

Compensated MSD of scattering particles and the corresponding magnitude viscoelastic modulus, |<i>G*(ω)</i>|, of 90% glycerol-10% water-TiO₂ suspensions.

<p>Panel (a) depicts the corrected MSD curves, deduced from <i>g₂^exp(t)</i> curves of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065014#pone-0065014-g004" target="_blank">Fig. 4</a> using <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065014#pone.0065014.e006" target="_blank">eqn. (6)</a>. The modified expression of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065014#pone.0065014.e006" target="_blank">eqn. (6)</a> resulted from PSCT-MCRT simulation of photon propagation and correlation transfer in LSR experimental setup considering the exact sample geometry and optical properties. Compared to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065014#pone-0065014-g005" target="_blank">Fig. 5(a)</a>, variability of MSD curves is significantly reduced, especially at intermediate times. Residual small deviations, still observed at very early or long times, are most likely due to electronic noise and speckle blurring, respectively. In panel (b) Generalized Stokes'-Einstein Relation is used to calculate |<i>G*(ω)</i>| from corrected MSD. It is observed that the variability between measured |<i>G*(ω)</i>| for different concentrations is considerably reduced, compared to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065014#pone-0065014-g005" target="_blank">Fig. 5(b)</a>. Moreover, a high correspondence is observed between LSR results for |<i>G*(ω)</i>| and mechanical rheometry.</p

LSR of 90% glycerol-10% water mixtures with varying scattering concentrations.

<p>Speckle intensity temporal autocorrelation curves, <i>g₂^exp(t)</i>, for aqueous glycerol mixtures of 90%G-10%W and various concentrations of TiO₂ scattering particles (0.04%–2%, corresponding to <i>μ′_s : 1.3–84.8 mm⁻¹</i>, N = 18), along with theoretical DLS and DWS curves (dotted lines). By changing the scattering concentration <i>g₂^exp(t)</i> curves sweep the transition area between the two theoretical limits. This data demonstrates the dependence of <i>g₂^exp(t)</i> on optical scattering in samples with identical mechanical properties.</p