The past decade has seen a rapid increase of numerical simulation studies on photobioreactors (PBRs). Developments in computational fluid dynamics (CFD) and the availability of more powerful ...computers have paved the way for the modeling and designing PRBs, a strategy that was abandoned from the late 1970s until the 1980s because of its complexity. This paper reviews the present status of numerical modeling for PBRs as well the application of CFD in the design of PBR for the mass production of microalgae. Emphasis is on the major breakthroughs in PBR design that may lead to scaling-up. Most simulations have been conducted in bubble column PBRs, which offer many advantages. Their geometry is simple in design with no moving parts, and they are easy to construct and operate. A majority of published simulation studies used two-phase models (air and water) and employed the Eulerian-Eulerian mixture model. CFD models have been vigorously validated by experimental and laboratory studies, with most claiming to have achieved good results. However, current PBR scale-up projects still need to resolve hydrodynamic issues within the PBR, in order to optimize factors for microalgal growth. To create ideal conditions inside the PBR, the main factors that influence microalgal growth such as light intensity and distribution, gas injection and mixing, and hydrodynamics/flow pattern which are the key for design and scale up must be thoroughly understood. The present practice of PBR design using CFD can be considered both an art and a science because of some numerical simulation issues which are yet to be resolved and the complexity of fluid mechanics inside the PBRs. Nonetheless, CFD has proven to be an effective tool in predicting the complex inherent phenomena in the PBRs. The CFD technique has shown to be very promising to successfully design and develop PBRs which can be commercially available for scale-up.
Intramuscular fat (IMF) in cattle is an important component of traits that influence meat quality. We measured carcass characteristics and gene expression in Korean steers to clarify the molecular ...mechanism(s) underlying IMF deposition in LM tissue by determining the correlation between IMF content and gene expression abundance and by developing models to predict IMF content using gene expression abundance. The deposition of IMF is determined by a balance between fat deposition and fat removal in the LM. We measured mRNA abundance of lipid metabolic genes including lipogenesis acetyl CoA carboxylase (ACC), fatty acid synthase (FASN), fatty lipid uptake lipoprotein lipase (LPL), fatty acid translocase (CD36), fatty acid transport protein 1 (FATP1), fatty acid esterification glycerol-3-phosphate acyltransferase 1 (GPAT1), acylglycerol phosphate acyltransferase 1 (AGPAT1), diacylglycerol acyltransferase 1 (DGAT1), DGAT2, lipolysis adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), monoglyceride lipase (MGL), and fatty acid oxidation carnitine palmitoyl transferase 1B, very long-chain acyl-CoA dehydrogenase (VLCAD), medium-chain acyl-CoA dehydrogenase (MCAD) in the LM. The mRNA abundance of the GPAT1 gene showed the greatest correlation (r = 0.74; P < 0.001) with IMF content among 9 fat deposition genes. The gene expression abundance of other fat deposition genes including ACC, FASN, LPL, CD36, FATP1, AGPAT1, DGAT1, and DGAT2 also exhibited significant positive correlations (P < 0.05) with IMF content in the LM. Conversely, ATGL mRNA abundance showed the greatest negative correlation (r = –0.68; P < 0.001) with IMF content in the LM among 6 fat removal genes. The expression of other fat removal genes including MGL, VLCAD, and MCAD showed significant negative correlations (P < 0.05) with IMF content. Our findings show that the combined effects of increases in lipogenesis, fatty acid uptake, fatty acid esterification, and of decreases in lipolysis and fatty acid oxidation contribute to increasing IMF deposition in Korean steers. The multiple regression analysis revealed that the mRNA abundance of the GPAT1 gene in the LM was the first major variable predicting IMF content (54%) among 15 lipid metabolic genes. The second was mRNA abundance of ATGL (11%). In conclusion, these results suggest that GPAT1 and ATGL genes could be used as genetic markers to predict IMF deposition in the LM.
Metastasis is a life-threatening feature of cancer and is primarily responsible for cancer patient mortality. Cross talk between tumor cells and endothelium is important for tumor progression and ...metastasis. However, very little is known about the mechanisms by which endothelial cells (ECs) that are close to tumor cells, respond to the tumor cells during tumor progression and metastasis. In this study, we exploited the use of EC-specific signal transducer activator of transcription 3 (STAT3) knockout mice to investigate the role of STAT3 in ECs in tumor progression and metastasis. We found that the loss of STAT3 in ECs did not affect primary Lewis lung carcinoma (LLC) tumor growth, but it reduced in vivo LLC metastasis in experimental and spontaneous metastasis models. Mechanistically, STAT3 activation upregulated cell adhesion molecule expression, including E-selectin and P-selectin, in murine endothelial MS-1 cells treated with tumor cell-conditioned media in vitro and in pre-metastatic lungs of tumor-bearing mice in vivo. We also found that both E-selectin and P-selectin were, at least in part, responsible for STAT3-induced adhesion and invasion of LLC cells through an EC monolayer. However, tumor cell-conditioned media from B16F10 melanoma cells did not activate STAT3 in MS-1 cells. As a result, EC STAT3 knockout did not affect B16F10 melanoma cell metastasis. In addition, various human cancer cells activated STAT3 in human ECs (HUVECs), resulting in increased cell adhesion molecule expression. Collectively, our findings demonstrate that STAT3 activation in ECs promotes tumor metastasis through the induction of cell adhesion molecules, demonstrating a role for ECs in response to tumor cells during tumor metastasis.
We report on a novel method for the photoassociation of strongly polar trilobite Rydberg molecules. This exotic ultralong-range dimer, consisting of a ground-state atom bound to the Rydberg electron ...via electron-neutral scattering, inherits its polar character from the admixture of high-angular-momentum electronic orbitals. The absence of low-L character hinders standard photoassociation techniques. Here, we show that for suitable principal quantum numbers the resonant coupling of the orbital motion with the nuclear spin of the perturber, mediated by electron-neutral scattering, hybridizes the trilobite molecular potential with the more conventional S-type molecular state. This provides a general path to associate trilobite molecules with large electric dipole moments, as demonstrated via high-resolution spectroscopy. We find a dipole moment of 135(45) D for the trilobite state. Our results are compared to theoretical predictions based on a Fermi model.
Abstract
Sri Lanka has no water scarcity within the country, and per capita, water availability is adequate to cater for the country's estimated peak population. Nevertheless, the frequent ...variability of spatial and temporal water availability and extreme events have built up a water scarcity in Sri Lanka, which has been observed during the last two to three decades. Therefore, effective and efficient water governance is most important in today's context, and regular review and amendment of policies, laws, and regulations are crucial to mitigate water scarcity. Although a few attempts were initiated, none of them succeeded. In this study, historical and present water governance mechanisms, including coordinating mechanisms and implementing water management agencies in Sri Lanka, were comprehensively reviewed. Further, the previously proposed water policies, their status and reasons for the failures of policies were discussed. Finally, the formulation of a novel institutional arrangement or altering the existing institutional arrangement with shared data and allocating non-shared responsibilities to each institution is suggested for better water governance in Sri Lanka.
Novel blue‐light‐emitting materials, 9,10‐bis(1,2‐diphenyl styryl)anthracene (BDSA) and 9,10‐bis(4′‐triphenylsilylphenyl)anthracene (BTSA), which are composed of an anthracene molecule as the main ...unit and a rigid and bulky 1,2‐diphenylstyryl or triphenylsilylphenyl side unit, have been designed and synthesized. Theoretical calculations on the three‐dimensional structures of BDSA and BTSA show that they have a non‐coplanar structure and inhibited intermolecular interactions, resulting in a high luminescence efficiency and good color purity. By incorporating these new, non‐doped, blue‐light‐emitting materials into a multilayer device structure, it is possible to achieve luminance efficiencies of 1.43 lm W–1 (3.0 cd A–1 at 6.6 V) for BDSA and 0.61 lm W–1 (1.3 cd A–1 at 6.7 V) for BTSA at 10 mA cm–2. The electroluminescence spectrum of the indium tin oxide (ITO)/copper phthalocyanine (CuPc)/1,4‐bis(1‐naphthylphenyl)‐aminobiphenyl (α‐NPD)/BDSA/tris(9‐hydroxyquinolinato)aluminum (Alq3)/LiF/Al device shows a narrow emission band with a full width at half maximum (FWHM) of 55 nm and a λmax = 453 nm. The FWHM of the ITO/CuPc/α‐NPD/BTSA/Alq3/LiF/Al device is 53 nm, with a λmax = 436 nm. Regarding color, the devices showed highly pure blue emission ((x,y) = (0.15,0.09) for BTSA, (x,y) = (0.14,0.10) for BDSA) at 10 mA cm–2 in Commission Internationale de l'Eclairage (CIE) chromaticity coordinates.
Deep‐blue organic light‐emitting diodes have been realized using new blue‐light‐emitting materials that contain an anthracene molecule as the main backbone and 1,2‐diphenylstyryl and tetraphenylsilane as the side units. The electroluminescence spectra of the non‐doped devices show a narrow emission band, almost perfectly matching the “standard” blue (see Figure). Thin films of the material are of high quality and thermally stable.
Biomarkers of acute human spinal cord injury (SCI) could provide a more objective measure of spinal cord damage and a better predictor of neurological outcome than current standardized neurological ...assessments. In SCI, there is growing interest in establishing biomarkers from cerebrospinal fluid (CSF) and from magnetic resonance imaging (MRI). Here, we compared the ability of CSF and MRI biomarkers to classify injury severity and predict neurological recovery in a cohort of acute cervical SCI patients. CSF samples and MRI scans from 36 acute cervical SCI patients were examined. From the CSF samples taken 24 h post-injury, the concentrations of inflammatory cytokines (interleukin IL-6, IL-8, monocyte chemotactic protein-1), and structural proteins (tau, glial fibrillary acidic protein, and S100β) were measured. From the pre-operative MRI scans, we measured intramedullary lesion length, hematoma length, hematoma extent, CSF effacement, cord expansion, and maximal spinal cord compression. Baseline and 6-month post-injury assessments of American Spine Injury Association Impairment Scale (AIS) grade and motor score were conducted. Both MRI measures and CSF biomarker levels were found to correlate with baseline injury grade, and in combination they provided a stronger model for classifying baseline AIS grade than CSF or MRI biomarkers alone. For predicting neurological recovery, the inflammatory CSF biomarkers best predicted AIS grade conversion, whereas structural biomarker levels best predicted motor score improvement. A logistic regression model utilizing CSF biomarkers alone had a 91.2% accuracy at predicting AIS conversion, and was not strengthened by adding MRI features or even knowledge of the baseline AIS grade. In a direct comparison of MRI and CSF biomarkers, the CSF biomarkers discriminate better between different injury severities, and are stronger predictors of neurological recovery in terms of AIS grade and motor score improvement. These findings demonstrate the utility of measuring the acute biological responses to SCI as biomarkers of injury severity and neurological prognosis.
Preservation of both anterior and posterior cruciate ligaments in total knee arthroplasty (TKA) can lead to near-normal post-operative joint mechanics and improved knee function. We hypothesised that ...a patient-specific bicruciate-retaining prosthesis preserves near-normal kinematics better than standard off-the-shelf posterior cruciate-retaining and bicruciate-retaining prostheses in TKA.
We developed the validated models to evaluate the post-operative kinematics in patient-specific bicruciate-retaining, standard off-the-shelf bicruciate-retaining and posterior cruciate-retaining TKA under gait and deep knee bend loading conditions using numerical simulation.
Tibial posterior translation and internal rotation in patient-specific bicruciate-retaining prostheses preserved near-normal kinematics better than other standard off-the-shelf prostheses under gait loading conditions. Differences from normal kinematics were minimised for femoral rollback and internal-external rotation in patient-specific bicruciate-retaining, followed by standard off-the-shelf bicruciate-retaining and posterior cruciate-retaining TKA under deep knee bend loading conditions. Moreover, the standard off-the-shelf posterior cruciate-retaining TKA in this study showed the most abnormal performance in kinematics under gait and deep knee bend loading conditions, whereas patient-specific bicruciate-retaining TKA led to near-normal kinematics.
This study showed that restoration of the normal geometry of the knee joint in patient-specific bicruciate-retaining TKA and preservation of the anterior cruciate ligament can lead to improvement in kinematics compared with the standard off-the-shelf posterior cruciate-retaining and bicruciate-retaining TKA.
: Y-G. Koh, J. Son, S-K. Kwon, H-J. Kim, O-R. Kwon, K-T. Kang. Preservation of kinematics with posterior cruciate-, bicruciate- and patient-specific bicruciate-retaining prostheses in total knee arthroplasty by using computational simulation with normal knee model.
2017;6:557-565. DOI: 10.1302/2046-3758.69.BJR-2016-0250.R1.
We investigated the influence of annealing and secondary warm rolling on the microstructural evolution and mechanical properties of a roll-bonded three-ply Al/Mg/Al sheet. After annealing at 300°C, ...the formation of an intermetallic compound (IMC) layer consisting of Mg17Al12 and Mg2Al3 was identified at the interface. Although the thickness of the IMC layer increased with increasing annealing or preheating time, secondary warm rolling after preheating at 300°C for 10min significantly reduced the thickness of the IMC layer below 1.5μm. Also an equiaxed and homogeneous grain morphology of the constituent magnesium alloy was successfully introduced. This resulted in strongly enhanced elongation up to magnesium fracture by 14.5%.
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