THE VALUATION OF BIOTECH IPOS

The valuation of initial public offerings (IPOs) is of considerable interest, given the important role these enterprises play in economic growth and investors' decisions. IPO valuation is particularly challenging due to the meager information available about new enterprises at offering dates. We extend the research on IPO valuation in various directions: First, we penetrate deep beyond the traditional proxies for value drivers, like R&D expenditures and cash flows, by defining and testing a host of specific product-related and competitive environment value drivers; second, we examine IPO valuations at three distinct phases of the going-public process; third, we employ both the direct valuation and relative valuation approaches; and fourth, we round up the analysis by examining the long-term performance of IPOs. Based on a sample of biotech IPOs that went public in the 1990s, we document the overwhelming importance of product-related and intellectual property fundamentals, as well as the irrelevance of several key signals, such as venture capital backing and the quality of underwriters, which played prominent roles in previous research

Top Rank Optimization in Linear Time

Bipartite ranking aims to learn a real-valued ranking function that orders positive instances before negative instances. Recent efforts of bipartite ranking are focused on optimizing ranking accuracy at the top of the ranked list. Most existing approaches are either to optimize task specific metrics or to extend the ranking loss by emphasizing more on the error associated with the top ranked instances, leading to a high computational cost that is super-linear in the number of training instances. We propose a highly efficient approach, titled TopPush, for optimizing accuracy at the top that has computational complexity linear in the number of training instances. We present a novel analysis that bounds the generalization error for the top ranked instances for the proposed approach. Empirical study shows that the proposed approach is highly competitive to the state-of-the-art approaches and is 10-100 times faster

Evolution of Zhangjiang National Independent Innovation Demonstration Zone’s Administration Function based on Ground Theory

Upon setting up, Zhangjiang National Independent Innovation Demonstration Zone has been playing its pioneer and model roles, who not only had made great achievements in the field of science & technology innovation and industrial park construction, but also had attempted successful reform in the aspect of administration function. The development and innovation of committee’s administration function can influence zhangjiang's capacity for independent innovation profoundly. This paper through the grounded theory analysis of Zhangjiang Demonstration Zone’s work plans from 2011 to 2014, studied the evolution of its administration committee’s administration functions and explored the development tendency of its administrative system reform, so as to provide effective guidance for the future development of Zhangjiang National Independent Innovation Demonstration Zone. Keywords: Grounded theory, Zhangjiang National independent innovation demonstration zone, Administration functio

Heavy-Ball-Based Hard Thresholding Algorithms for Sparse Signal Recovery

The hard thresholding technique plays a vital role in the development of algorithms for sparse signal recovery. By merging this technique and heavy-ball acceleration method which is a multi-step extension of the traditional gradient descent method, we propose the so-called heavy-ball-based hard thresholding (HBHT) and heavy-ball-based hard thresholding pursuit (HBHTP) algorithms for signal recovery. It turns out that the HBHT and HBHTP can successfully recover a $k$-sparse signal if the restricted isometry constant of the measurement matrix satisfies $\delta_{3k}<0.618$ and $\delta_{3k}<0.577,$ respectively. The guaranteed success of HBHT and HBHTP is also shown under the conditions $\delta_{2k}<0.356$ and $\delta_{2k}<0.377,$ respectively. Moreover, the finite convergence and stability of the two algorithms are also established in this paper. Simulations on random problem instances are performed to compare the performance of the proposed algorithms and several existing ones. Empirical results indicate that the HBHTP performs very comparably to a few existing algorithms and it takes less average time to achieve the signal recovery than these existing methods

THE VALUATION OF BIOTECH IPOS

The valuation of initial public offerings (IPOs) is of considerable interest, given the important role these enterprises play in economic growth and investors' decisions. IPO valuation is particularly challenging due to the meager information available about new enterprises at offering dates. We extend the research on IPO valuation in various directions: First, we penetrate deep beyond the traditional proxies for value drivers, like R&D expenditures and cash flows, by defining and testing a host of specific product-related and competitive environment value drivers; second, we examine IPO valuations at three distinct phases of the going-public process; third, we employ both the direct valuation and relative valuation approaches; and fourth, we round up the analysis by examining the long-term performance of IPOs. Based on a sample of biotech IPOs that went public in the 1990s, we document the overwhelming importance of product-related and intellectual property fundamentals, as well as the irrelevance of several key signals, such as venture capital backing and the quality of underwriters, which played prominent roles in previous research

Direct correlation of electrochemical behaviors with anti-thrombogenicity of semiconducting titanium oxide films

Biomaterials-associated thrombosis is dependent critically upon electrochemical response of fibrinogen on material surface. The relationship between the response and anti-thrombogenicity of biomaterials is not well-established. Titanium oxide appears to have good anti-thrombogenicity and little is known about its underlying essential chemistry. We correlate their anti-thrombogenicity directly to electrochemical behaviors in fibrinogen containing buffer solution. High degree of inherent n-type doping was noted to contribute the impedance preventing charge transfer from fibrinogen into film (namely its activation) and consequently reduced degree of anti-thrombogenicity. The impedance was the result of high donor carrier density as well as negative flat band potential

Glechoma longituba (Lamiaceae) alleviates apoptosis in calcium oxalate-induced oxidative stress in kidney proximal tubule epithelial cell line, HK-2

Purpose: To investigate the effects of Glechoma longituba on calcium oxalate (CaOx)-induced stress in HK-2 cells as a possible treatment strategy for nephrolithiasis (kidney stones).Methods: Human kidney HK-2 cells were treated with CaOx and Glechoma longituba at different concentrations. The levels of reactive oxygen species (ROS), lactate dehydrogenase (LDH), and malondialdehyde (MDA) were measured. Cell apoptosis and viability were assessed by flow cytometry and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, respectively, while apoptosis-related proteins were determined using western blotting. The levels of the nuclear factorerythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and NADPH-quinone-oxidoreductase 1 (NQO-1) genes were evaluated using quantitative real-time polymerase chain reaction (qRT-PCR). Using lentivirus, Nrf2 was knocked down in HK-2 cells, and this was confirmed by both qRT-PCR and western blotting. Scramble and si-Nrf2 transfected HK-2 cells were treated with CaOx and Glechoma longituba, and ROS levels and apoptosis were also assessed.Results: CaOx significantly increased the levels of ROS, LDH and MDA, while Glechoma longituba pretreatment attenuated these elevations in a dose-dependent manner. CaOx treatment increased cell apoptosis and decreased cell viability (p &lt; 0.05), while Glechoma longituba pre-treatment abolished these effects in a dose-dependent manner. Glechoma longituba pre-treatment significantly upregulated the expressions of Nrf2, HO-1 and NQO-1 (p &lt; 0.05). In HK-2 cells, Si-Nrf-2 attenuated the effects of Glechoma longituba pre-treatment on cell oxidative stress and apoptosis induced by CaOx.Conclusion: Glechoma longituba pre-treatment attenuates cell apoptosis and oxidative stress induced by CaOx via Nrf2/HO-1 signalling pathway. Thus, the plant is a potential source of agents for the treatment of nephrolithiasis.Keywords: Glechoma longituba, Nephrolithiasis, Nuclear factor-erythroid 2-related factor 2, Oxidative stress, Apoptosi

Expression of CD147 on monocytes/macrophages in rheumatoid arthritis: its potential role in monocyte accumulation and matrix metalloproteinase production

Monocytes/macrophages play an important role in rheumatoid arthritis (RA) pathogenesis. They can activate fibroblasts through many molecules, including IL-1 and tumor necrosis factor-alpha, but there have been very few reports on the role of CD147 in RA. In our study, the results of flow cytometry reveal that the mean fluorescence intensity (MFI) of CD147 expression on CD14+ monocytes of peripheral blood from RA patients was higher than that in normal control and ankylosing spondylitis (AS) patients. The MFI of CD147 expression on the CD14+ monocytes in RA synovial fluid was higher than that in RA peripheral blood. Immunohistochemical staining shows that CD147 expression in RA synovium correlated with matrix metalloproteinase (MMP)-1 expression. A double immunofluorescent assay shows that CD147 was expressed on CD68+ cells in RA synovium. The potential role of CD147 in cyclophilin A (CyPA)-mediated cell migration was studied using a chemotaxis assay in vitro and it was found that the addition of anti-CD147 antibody or a CD147 antagonistic peptide significantly decreased the chemotactic index of the mononuclear cells. The role of CD147 in MMP production and cell invasion in vitro were studied through the co-culture of human CD14+ monocytes or monocytic line THP-1 cells and human fibroblasts, as well as by gel zymography and an invasion assay. Significantly elevated release and activation of MMP-9 and/or MMP-2 were seen in the co-culture of human monocytes/THP-1 cells and fibroblasts compared with cultures of the cells alone. An increased number of cells invading through the filters in the invasion assays was also observed in the co-cultured cells. The addition of CD147 antagonistic peptide had some inhibitory effect, not only on MMP production but also on cell invasion in the co-culture. Our study demonstrates that the increased expression of CD147 on monocytes/macrophages in RA may be responsible for elevated MMP secretion, cell invasion and CyPA-mediated cell migration into the joints, all of which may contribute to the cartilage and bone destruction of RA. These findings, together with a better understanding of CD147, CyPA and RA, will help in the development of innovative therapeutic interventions for RA

Arrayed van der Waals Vertical Heterostructures based on 2D GaSe Grown by Molecular Beam Epitaxy

Vertically stacking two dimensional (2D) materials can enable the design of novel electronic and optoelectronic devices and realize complex functionality. However, the fabrication of such artificial heterostructures in wafer scale with an atomically-sharp interface poses an unprecedented challenge. Here, we demonstrate a convenient and controllable approach for the production of wafer-scale 2D GaSe thin films by molecular beam epitaxy. In-situ reflection high-energy electron diffraction oscillations and Raman spectroscopy reveal a layer-by-layer van der Waals epitaxial growth mode. Highly-efficient photodetector arrays were fabricated based on few-layer GaSe on Si. These photodiodes show steady rectifying characteristics and a relatively high external quantum efficiency of 23.6%. The resultant photoresponse is super-fast and robust with a response time of 60 us. Importantly, the device shows no sign of degradation after 1 million cycles of operation. Our study establishes a new approach to produce controllable, robust and large-area 2D heterostructures and presents a crucial step for further practical applications