Some new developments in image compression

This study is divided into two parts. The first part involves an investigation of near-lossless compression of digitized images using the entropy-coded DPCM method with a large number of quantization levels. Through the investigation, a new scheme that combines both lossy and lossless DPCM methods into a common framework is developed. This new scheme uses known results on the design of predictors and quantizers that incorporate properties of human visual perception. In order to enhance the compression performance of the scheme, an adaptively generated source model with multiple contexts is employed for the coding of the quantized prediction errors, rather than a memoryless model as in the conventional DPCM method. Experiments show that the scheme can provide compression in the range from 4 to 11 with a peak SNR of about 50 dB for 8-bit medical images. Also, the use of multiple contexts is found to improve compression performance by about 25% to 35%;The second part of the study is devoted to the problem of lossy image compression using tree-structured vector quantization. As a result of the study, a new design method for codebook generation is developed together with four different implementation algorithms. In the new method, an unbalanced tree-structured vector codebook is designed in a greedy fashion under the constraint of rate-distortion trade-off which can then be used to implement a variable-rate compression system. From experiments, it is found that the new method can achieve a very good rate-distortion performance while being computationally efficient. Also, due to the tree-structure of the codebook, the new method is amenable to progressive transmission applications

The Histone Demethylases Jhdm1a/1b Enhance Somatic Cell Reprogramming in a Vitamin-C-Dependent Manner

SummaryReprogramming of somatic cells into induced pluripotent stem cells (iPSCs) resets the epigenome to an embryonic-like state. Vitamin C enhances the reprogramming process, but the underlying mechanisms are unclear. Here we show that the histone demethylases Jhdm1a/1b are key effectors of somatic cell reprogramming downstream of vitamin C. We first observed that vitamin C induces H3K36me2/3 demethylation in mouse embryonic fibroblasts in culture and during reprogramming. We then identified Jhdm1a/1b, two known vitamin-C-dependent H3K36 demethylases, as potent regulators of reprogramming through gain- and loss-of-function approaches. Furthermore, we found that Jhdm1b accelerates cell cycle progression and suppresses cell senescence during reprogramming by repressing the Ink4/Arf locus. Jhdm1b also cooperates with Oct4 to activate the microRNA cluster 302/367, an integral component of the pluripotency machinery. Our results therefore reveal a role for H3K36me2/3 in cell fate determination and establish a link between histone demethylases and vitamin-C-induced reprogramming

Progressive Impairment of Motor Skill Learning in a D-Galactose- Induced Aging Mouse Model

Abstract.-Chronic administration of D-galactose (D-gal) has been reported to cause behavioral deterioration in mice similar to what is observed in the aging process, but the effect of D-gal on motor skill learning has not been examined. In the present study, mice were treated with D-gal (100 mg/kg/day) for a period ranging from 1 to 9 weeks, and motor skill learning was assessed using the rotarod test. D-gal-treated mice exhibited deficits in performance, including a shorter latency to fall and a decrease in intersession improvement compared to controls. Notably, motor skill deficiencies in mice subjected to short-term D-gal treatment (2-4 weeks) were rescued through repeated training, while there was no comparable improvement in mice receiving D-gal over a long term (≥ 5 weeks). The decline in rotarod performance reached a plateau at 7 weeks of D-gal exposure, suggesting that there is a ceiling effect. These results provide evidence that D-gal impairs motor learning capacity in a time-dependent manner, and demonstrate that chronic administration of D-gal is a reliable model for the behavioral decline associated with aging

Vitamin C Enhances the Generation of Mouse and Human Induced Pluripotent Stem Cells

SummarySomatic cells can be reprogrammed into induced pluripotent stem cells (iPSCs) by defined factors. However, the low efficiency and slow kinetics of the reprogramming process have hampered progress with this technology. Here we report that a natural compound, vitamin C (Vc), enhances iPSC generation from both mouse and human somatic cells. Vc acts at least in part by alleviating cell senescence, a recently identified roadblock for reprogramming. In addition, Vc accelerates gene expression changes and promotes the transition of pre-iPSC colonies to a fully reprogrammed state. Our results therefore highlight a straightforward method for improving the speed and efficiency of iPSC generation and provide additional insights into the mechanistic basis of the reprogramming process

Some new developments in image compression

This study is divided into two parts. The first part involves an investigation of near-lossless compression of digitized images using the entropy-coded DPCM method with a large number of quantization levels. Through the investigation, a new scheme that combines both lossy and lossless DPCM methods into a common framework is developed. This new scheme uses known results on the design of predictors and quantizers that incorporate properties of human visual perception. In order to enhance the compression performance of the scheme, an adaptively generated source model with multiple contexts is employed for the coding of the quantized prediction errors, rather than a memoryless model as in the conventional DPCM method. Experiments show that the scheme can provide compression in the range from 4 to 11 with a peak SNR of about 50 dB for 8-bit medical images. Also, the use of multiple contexts is found to improve compression performance by about 25% to 35%;The second part of the study is devoted to the problem of lossy image compression using tree-structured vector quantization. As a result of the study, a new design method for codebook generation is developed together with four different implementation algorithms. In the new method, an unbalanced tree-structured vector codebook is designed in a greedy fashion under the constraint of rate-distortion trade-off which can then be used to implement a variable-rate compression system. From experiments, it is found that the new method can achieve a very good rate-distortion performance while being computationally efficient. Also, due to the tree-structure of the codebook, the new method is amenable to progressive transmission applications.</p

ISAT-1 Communication System

The communication system of the Iowa satellite ISAT-1 provides contact links between the satellite, the ground station, and a moderate number of remote ground data collection systems through the operation of two functional units. In this system, data is transferred over four VHF/UHF channels, each with a bandwidth of 15 KHz, at the rate of 9,600 bps per channel. The continuous phase binary frequency shift keying (CP-BFSK) is used for digital modulation/demodulation in the attempt to achieve a transmission error bit rate of 10(-6) or lower under the constraint of a very limited financial and power budget. Also, a command-driven time division multiple access (CD-TDMA) scheme is employed for data exchange between the remote data collection systems and the central ground station in order that the communication resources be utilized efficiently and effectively. In this paper, different aspects of the system, including the specifications and the preliminary designs of all operation blocks, are described in detail

Fentanyl Exerts an Antitumor Effect on Papillary Thyroid Cancer by Regulating the miR-204/KLF5 Axis

Fentanyl is a strong anesthetic analgesic drug that plays important roles in many types of cancers. However, the role of fentanyl in papillary thyroid cancer (PTC) tumor development remains ambiguous. In this study, we aimed to investigate the potential antitumor effects of fentanyl on PTC cell viability and invasion. Results of cell counting kit-8 and Transwell assays demonstrated that fentanyl treatment (5 ng/ml) reduced the viability and invasion of two PTC cells, TCP-1 and BCPAP. Our data subsequently showed that fentanyl induced antitumor effects by increasing miR-204 expressions. Furthermore, the results of luciferase reporter assays identified that miR-204 directly targets Krüppel-like transcription factor 5 (KLF5), which serves as tumor-promoting genes in many cancers. Further mechanistic analyses revealed that fentanyl performs its tumor-suppressive functions by regulating the miR-204/KLF5 axis in PTC cells. These results contribute to understanding the important role of fentanyl in treating PTC

Comprehensive Genomics and Proteomics Analysis Reveals the Multiple Response Strategies of Endophytic <i>Bacillus</i> sp. WR13 to Iron Limitation

Iron (Fe) is an important metal element for the growth of bacteria. Many bacteria respond to Fe limitation through a variety of strategies. We previously isolated an endophyte Bacillus sp. WR13 from wheat root. However, whether and how this strain can cope with Fe-deficient environments remains unclear. In this study, the growth of WR13 under Fe starvation was investigated, and the underlying mechanisms of WR13 in response to Fe starvation were elucidated via genomics and iTRAQ-based proteomics. Under Fe limitation, WR13 showed a growth pattern similar to that of Fe sufficiency. Genomics analysis demonstrated that WR13 had gene clusters related to siderophore synthesis (dhbACEBF), transportation (bcbE), uptake (feuABC-yusV) and hydrolysis (besA). These genes were significantly up-regulated in Fe-starved WR13, which resulted in more siderophore production. Proteomics data revealed that many Fe-containing proteins such as ACO, HemQ, ferredoxin, CNP, and SufD were significantly reduced under Fe limitation. Meanwhile, significant decreases in many proteins involved in glycolysis, TCA cycle, pentose phosphate pathway; asparagine, glutamine, methionine, and serine metabolism; and phospholipid hydrolysis were also observed. Overall, this study shows that Bacillus sp. WR13 was able to respond to Fe limitation via multiple strategies and provides a theoretical basis for the application of WR13 in Fe-deficient soil