Real-time in-situ optical detection of fluid viscosity based on the Beer-Lambert law and machine learning.

As an important physical quantity to describe the resistance of fluid to flow, viscosity is an essential property of fluids in fluid mechanics, chemistry, medicine, as well as hydraulic engineering. While traditional measurement methods, including the rotating-cylinder method, capillary tube method and falling sphere method, have significant drawbacks especially in terms of accuracy, response time and the sample must be made to move. In this work, a novel Beer-Lambert law-based method was proposed for the viscosity measurement. Specifically, this work demonstrates that viscosity can be quantitatively reflected by spectral line intensity, and castor oil was selected due to its viscous temperature properties (viscosity has been accurately measured under different temperature), and its transmission spectrum at different temperatures ranging from 10 to 50°C was detected firstly. Then, the principal component analysis (PCA) was employed to obtain the intrinsic features of the transmission spectrum. Finally, the processed data was utilized to train and verify the radial basis function (RBF) neural network. As a result, the accuracy of the predictions conducted by means of the RBF reached 98.45%, which indicates the complicated and non-linear relationships between spectra formation and viscosity can be depicted well by RBF. The results show that the real-time in-situ optical detection method adopted in this work represents a great leap forward in the viscosity measurement, which fundamentally reforms the traditional viscosity measurement methods.

Real-time monitoring of carbon concentration using laser-induced breakdown spectroscopy and machine learning.

The spectral analysis based on laser-induced breakdown spectroscopy (LIBS) is an effective approach to carbon concentration monitoring. In this work, a novel LIBS-based method, together with a system designed independently, was developed for carbon monitoring. The experiments were conducted in two modes: static and dynamic. In static monitoring, gases in three scenarios were selected to represent different carbon concentrations, based on which measurements of carbon concentrations were performed through a mathematical model. Then, K-nearest Neighbors (KNN) was adopted for classification, and its accuracy could reach 99.17%, which can be applied for the identification of gas composition and pollution traceability. In dynamic monitoring, respiration and fossil fuel combustion were selected because of their important roles in increasing carbon concentration. In addition, the simulation of combustion degree was performed by the radial basis function (RBF) based on the spectral information, where the accuracy reached 96.41%, which is the first time that LIBS is proposed to be used for combustion prediction. The innovative approach derived from LIBS and machine learning algorithms is fast, online, and in-situ, showing far-reaching application prospects in real-time monitoring of carbon concentrations.

Vaccination with photodynamic therapy-treated macrophages induces highly suppressive T-regulatory cells.

BACKGROUND/PURPOSE: The present study explores whether photodynamic therapy (PDT)-induced apoptosis can increase the number of tolerogenic regulatory T cells (Treg) and limit collateral tissue damage. METHODS: BALB/c mice were vaccinated subcutaneously three times with PDT-induced apoptotic or thaw-frozen, necrotic non-infected autologous macrophages (MΦ). Two weeks after the last vaccination, mice were infected intradermally with 10(6) promastigotes of Leishmania major. RESULTS: Mice that received PDT-induced apoptotic MΦ had fewer parasites and higher numbers of Treg than mice vaccinated with thaw-frozen necrotic MΦ or phosphate-buffered saline (PBS). Interleukin (IL)-4 and IL-6 were significantly suppressed, while IL-10 was increased in mice that received the PDT-induced apoptotic MΦ. The role of Treg in this process was confirmed through Treg transfer from vaccinated to naïve mice. Mice receiving CD4(+) CD25(+) cells from mice vaccinated with PDT-induced apoptotic MΦ showed smaller lesions 3 weeks after infection and lower parasitic burdens than mice that received Tregs from mice of thaw-frozen necrotic MΦ or PBS groups. These changes were mediated by the depletion of CD3(+) CD8(+) and NKT cells and increased levels of IL-12p70 and interferon-γ, IL-10, and TGF-ß in the cutaneous leishmaniasis lesions. CONCLUSION: Vaccination with apoptotic MΦ-induced tolerogenic Treg cells that limited collateral tissue damage and diminished parasitic burden.

[Adult stem cells and possible mechanisms of its differentiation--editorial].

Adult stem cells are the multi-potential cells, which exist in fetal and adult tissues. It can reproduce itself (undergo self-renewal) or give rise to more specialized (differentiated) cells. Under certain inducing conditions, adult stem cells can acquire the ability to differentiate into different tissue cells. Multipotent adult progenitor cells (MAPC), an alternative name of adult stem cell given by Catherine Verfaillie, existing in bone marrow, can differentiate into cells with characteristics of mesodermal, neuroectodermal, and endodermal lineages in vitro at the single-cell level. MAPC can also contribute to most cell types when injected into the blastocyst. Adult stem cell differentiation implies that different cell lineages are derived from a single initial cell; all differentiated cell types are functional in vitro and in vivo; and engraftment is robust and persistent in the physiological and pathological situations. The possible mechanisms may underlie the differentiation: various tissue-specific stem cells are present in different organs; adult stem cells would be reprogrammed when removed from their usual microenvironment and introduced into a different niche that imparts signals to activate a novel genetic program needed for the new cell fate. And true multi-potential stem cells persist in postnatal life. In the future, multi-potent adult stem cells might then be used for therapies of degenerative or genetic disorders of multiple different organs.

[Hematopoietic growth factor EPO has neuro-protective and neuro-trophic effects--review].

Erythropoietin (EPO) is an acidic glycoprotein that was first detected as a hematopoietic factor and its synthesis is triggered in response to cellular hypoxia-sensing. EPO binds to type I cytokine receptors, which associate with the non-receptor tyrosine kinase Jak2, and thereby activate Stat 5a/5b, Ras/MAPK, and PI3-K/Akt signaling pathways. The recent discovery shows that there is a specific EPO/EPO-receptor system in the central nervous system (CNS), independently of the haematopoietic system. Hypoxia and anemia can up-regulate EPO/EPOR expressions in the CNS. Further studies demonstrate that EPO has substantial neuro-protective effects and acts as a neurotrophic factor on central cholinergic neurons, influencing their differentiation and regeneration. EPO also exerts neuro-protective activities in different models of brain damage in vivo and in vitro, such as hypoxia, cerebral ischaemia and sub-arachnoid haemorrhage. EPO may also be involved in synaptic plasticity via the inhibition or stimulation of various neurotransmitters. Therefore, human recombinant EPO that activate its receptors in the central nervous system might be utilized in the future clinical practice involving neuroprotection and brain repair.

[Effects of hyperthermia on brainstem auditory evoked potentials and middle latency response in rats].

AIM: To study the effects of hyperthermia on brainstem auditory evoked potentials (BAEP) and middle latency response (MLR) in rats. METHODS: BAEP and MLR were recorded at the skull surface of rats. The body temperature of anesthetized rats increased gradually with a physical method and was detected by a digital thermometer inserted into the rectum. The peak latency (PL), interpeak latency (IPL), wave amplitude and the critical body temperature at which BAEP and MLR completely lost had been observed. RESULTS: All PL and I - II, I - III and I -IV IPL of BAEP shortened more and more as the body temperature increased step by step from 37 degrees C to 41.5 degrees C. But all PL and I - II and I -IV IPL did not shortened further and prolonged a little contrary as the body temperature at 42 degrees C and over 42 degrees C. All PL and P1-P3 and P2-P3 IPL of MLR also shortened as the body temperature increased from 37 degrees C to 43 degrees C. The wave amplitudes of BAEP and MLR decreased as the body temperature increased, especially as the body temperature over 42 degrees C. BAEP and MLR lost completely and synchronously at the body temperature (43.1 +/- 0.5) degrees C, which was not reversed as the body temperature returning to normal by cooling. CONCLUSION: There were obvious effects of hyperthermia on both BAEP and MLR in rats, and irreversible impairments appeared at a critical body temperature.