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ABSTRACT: This paper studies a service firm whose business time can be divided into several periods, each providing different value
to customers. Heterogeneous service is a major reason resulting in imbalances between supply and demand. Since customers differ
in their degree of impatience, firms can use differential pricing mechanisms to optimize their objectives and match supply
with demand in each period, by inducing customers to choose different periods. We study two types of firms, an internal firm,
the objective of which is to maximize the system’s (including the firm and all the customers) total net value, and a commercial
firm, which aims to optimize its own profit. Though impatience factors are customers’ private information, for each type of
firm, we derive the optimal incentive compatible pricing policy, under which all the coming customers will follow the firm’s
assignment, that is, patient customers will buy the service in high-value periods, but their waiting time will be longer,
while impatient customers will enter into the low-value periods, but they will be compensated by shorter waiting times. Furthermore,
in the internal firm, we also prove that this mechanism enables the decentralization of decisions, while maintaining centralized
system-wide optimality. Numerical analysis shows that when there is sufficient capacity, the internal firm does not always
need to set lower prices than the commercial firm in every period.
Journal of Systems Science and Systems Engineering 04/2012; 17(1):50-65. · 0.43 Impact Factor
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ABSTRACT: Recent evidence from rodent ovaries has demonstrated expression of fractalkine and the existence of fractalkine receptor, and showed that there is a significant increase in steroidogenesis in response to fractalkine, yet the role of fractalkine and CX3CR1 in the human ovary is still unknown. This study aimed to determine the expression levels of fractalkine and CX3CR1 in the human ovary and to investigate their roles in sexual hormone biosynthesis by human luteinising granulosa cells. This is the first detailed report of fractalkine and CX3CR1 expression and function in the human ovary.
Fractalkine and CX3CR1 expression levels were measured by immunohistochemistry using ovarian tissue from pathological specimens from five individuals. Granulosa cells were obtained from patients during IVF treatment. They were cultured and treated with increasing doses of hCG with or without fractalkine. Media were collected to detect estradiol and progesterone by chemiluminescence. StAR, 3-βHSD and CYP11A expression were determined in granulosa cells treated with or without fractalkine by real-time RT-PCR.
Fractalkine and CX3CR1 were expressed in the human ovary and in luteinising granulosa cells. However, fractalkine expression was stronger in luteinising granulosa cells. Treatment with fractalkine augmented hCG stimulation of progesterone production in a dose-dependent manner with concomitant increases in transcript levels for key steroidogenic enzymes (StAR, 3-βHSD and CYP11A) but had no effect on estradiol biosynthesis (P<0.05).
Fractalkine and CX3CR1 were found to express in human ovary and luteinising granulosa cells. Fractalkine can increase the biosynthesis of progesterone in a dose-dependent manner by enhancing transcript levels of key steroidogenic enzymes.
Reproductive Biology and Endocrinology 06/2011; 9:95. · 2.05 Impact Factor
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ABSTRACT: In mammalian ovaries, diverse paracrine factors have been identified to mediate or modulate LH-induced changes during ovulation. Due to the difficulty in obtaining non-stimulated granulosa cells during IVF, little is known about the LH-induced paracrine factors in the human ovary. Based on earlier studies using murine ovarian cells showing the paracrine roles of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) in promoting oocyte maturation, we investigated the expression of these ligands in human granulosa cells and their regulation of human oocyte development.
Non-stimulated granulosa cells were obtained from non-stimulated IVM (in vitro maturation) patients after oocyte retrieval. Women undergoing non-stimulated IVM treatment at a mean age of 30.8 ± 1.3 (n = 10) were recruited for this study. Immature oocytes and granulosa cells were collected from IVF patients undergoing gonadotrophin stimulation and ICSI. Immunocytochemical analyses of granulosa cells were carried out to investigate expression profiles of BDNF and GDNF, together with real-time RT-PCR to analyze the gonadotrophin regulation of BDNF and GDNF transcript levels. In addition, immature oocytes were cultured to analyze the regulation of oocyte maturation by BDNF and GDNF.
BDNF and GDNF were found to be expressed in non-stimulated granulosa cells. After gonadotrophin (FSH and/or hCG) treatment, transcripts levels for BDNF and GDNF were significantly increased (P < 0.05). In cultured immature oocytes, treatment with BDNF or GDNF promoted total yields of metaphase II oocytes.
These findings demonstrate that FSH and hCG treatments augment the expression of BDNF and GDNF by granulosa cells and that these granulosa-cell-derived factors are candidate paracrine factors capable of promoting oocyte maturation.
Human Reproduction 03/2011; 26(3):695-702. · 4.47 Impact Factor
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European Journal of Operational Research. 01/2011; 215:70-79.
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ABSTRACT: In this paper, a new medical imaging strategy based on mobile phone is developed to obtain the quantitative temperature mappings of human skin. The visual images reflected by the TLC pre-painted on human skin are captured by the camera of mobile phone and transformed to the thermographies of human skin through digital image processing method according to the Temperature-Hue curve pre-established in the calibration experiment. The mobile phone acquired imaging is then applied to reconstruct the temperature distribution of dorsal hand and for thermodynamic check. Additional thermal parameters related to body health status are calculated based on the bioheat transfer model of human body. The present method is expected to be developed as a pervasive and low cost way to map the skin temperature imaging of human body.
Zhongguo yi liao qi xie za zhi = Chinese journal of medical instrumentation 09/2010; 34(5):317-22.
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ABSTRACT: Application of clinical digital medical imaging has raised many tough issues to tackle, such as data storage, management, and information sharing. Here we investigated a mobile phone based medical image management system which is capable of achieving personal medical imaging information storage, management and comprehensive health information analysis. The technologies related to the management system spanning the wireless transmission technology, the technical capabilities of phone in mobile health care and management of mobile medical database were discussed. Taking medical infrared images transmission between phone and computer as an example, the working principle of the present system was demonstrated.
Zhongguo yi liao qi xie za zhi = Chinese journal of medical instrumentation 05/2010; 34(3):167-71.
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Lin Yu,
Yang Wang, Shuo Huang,
Jianjun Wang,
Zengqin Deng,
Qi Zhang,
Wei Wu,
Xingliang Zhang,
Zhao Liu,
Weimin Gong,
Zhongzhou Chen
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ABSTRACT: Dynamic regulation of histone methylation/demethylation plays an important role during development. Mutations and truncations in human plant homeodomain (PHD) finger protein 8 (PHF8) are associated with X-linked mental retardation and facial anomalies, such as a long face, broad nasal tip, cleft lip/cleft palate and large hands, yet its molecular function and structural basis remain unclear. Here, we report the crystal structures of the catalytic core of PHF8 with or without alpha-ketoglutarate (alpha-KG) at high resolution. Biochemical and structural studies reveal that PHF8 is a novel histone demethylase specific for di- and mono-methylated histone H3 lysine 9 (H3K9me2/1), but not for H3K9me3. Our analyses also reveal how human PHF8 discriminates between methylation states and achieves sequence specificity for methylated H3K9. The in vitro demethylation assay also showed that the F279S mutant observed in clinical patients possesses no demethylation activity, suggesting that loss of enzymatic activity is crucial for pathogenesis of PHF8 patients. Taken together, these results will shed light on the molecular mechanism underlying PHF8-associated developmental and neurological diseases.
Cell Research 02/2010; 20(2):166-73. · 8.19 Impact Factor
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ABSTRACT: To evaluate the role of apolipoprotein C-I (apoC-I) levels and assess relationships between apoC-I and clinical features in women with polycystic ovary syndrome (PCOS).
Prospective study.
Reproductive Center of Peking University Third Hospital.
Thirty patients with PCOS with insulin resistance, 30 patients with PCOS without insulin resistance, and 30 control individuals.
Fasting serum samples.
Measures of serum apoC-I, androgens, total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apoA1, apoB, heat-shock C-reactive protein, glucose, and homeostasis model assessment of insulin resistance (HOMA-IR).
We found differentially expressed proteins by use of the surface-enhanced laser adsorption/ionization (SELDI) protein chip in the serum of women with PCOS and controls. Of these, apoC-I, was highly up-regulated. ApoC-I is associated with glycometabolism and lipid metabolism, but its role in PCOS has been unknown. The serum levels of apoC-I in the patients with PCOS were statistically significantly elevated compared with those of controls, especially in women with insulin resistance. The lean PCOS women had higher apoC-I levels than controls. In patients with PCOS and without any abnormal serum lipid index, apoC-I levels were still higher than in controls. Analysis showed that apoC-I correlated with body mass index, triglycerides, high-density lipoprotein cholesterol, apoA1, and HOMA-IR.
ApoC-I may have an important role in glucose and lipid metabolism, and may be useful for early demonstration of metabolic abnormality in women with PCOS.
Fertility and sterility 05/2009; 94(1):205-10. · 3.97 Impact Factor
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ABSTRACT: To characterize and compare the effect of DHEA and insulin plus hCG on ovarian morphology, estrous cycle, hormonal levels, insulin sensitivity, and the regulation of insulin signaling in rats.
Animal model study.
University laboratory.
Female Sprague-Dawley rats.
Female rats received DHEA or insulin plus hCG by continuous administration.
Ovarian morphology, estrous cycle, hormonal levels, insulin sensitivity, protein levels, and phosphorylation state of glycogen synthase kinase-3beta and extracellular regulated kinase 1/2 in the ovary.
Rats treated with DHEA displayed anovulation, insulin resistance, and polycystic ovaries characterized by cysts and a diminished granulosa layer. In contrast, insulin plus hCG results in acyclicity with increasing androgen biosynthesis and ovarian morphology different from that in DHEA-treated rats. Moreover, we found that insulin-stimulated serine-phosphorylation of glycogen synthase kinase-3beta was higher in insulin plus hCG-treated rats but lower in DHEA-treated rats. Furthermore, basal and insulin-stimulated tyrosine-phosphorylation of extracellular regulated kinase 1/2 was higher in DHEA-treated rats than in controls.
Notwithstanding that both the hyperandrogenism and the hyperinsulinemia synergistic with hCG-treated rats displayed the typical traits of human polycystic ovary syndrome, there is a divergence in the insulin-signaling pathway in the ovarian tissue, which may have a role in the pathogenesis of polycystic ovary syndrome.
Fertility and sterility 12/2008; 92(4):1447-55. · 3.97 Impact Factor
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Shuo Huang
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ABSTRACT: Products substitutions are frequently met in real life. In this paper, we study a continuous review two-product inventory system with products substitutions. Given safety stock levels and demand arrival rates, we provide an efficient procedure to evaluate system performances under different substitution policies, and then the optimal substitution rule is straightforward. Simulation studies conducted to test the validity of this procedure indicate that it performs very well. Lastly we give some numerical results to analyze the effects of different parameters on the optimal rule.
Services Systems and Services Management, 2005. Proceedings of ICSSSM '05. 2005 International Conference on; 07/2005
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ABSTRACT: In this paper we consider the inventory system of an online retailer. The retailer continuously reviews and replenishes inventory according to a (Q, R) policy. We assume Poisson demand and constant lead times. Normally the customers will accept a reasonable period of waiting time after they issued their orders because of the purchasing convenience of the online business. With this period of waiting time, the online retailer has a response time to the customer orders even when a shortage occurs, but without incurring any penalty cost. We call this period of time as retailer committed service time. However, after the committed service time, if the retailer is still in shortage, the customer demands will be filled by emergency orders or backordered with a time dependent backorder cost. Based on the real time information of the outstanding orders of the retailer and the waiting time of the customers, we give a decision rule to minimize the expected cost under the assumption that no further emergency orders will take place. Numerical examples to illustrate the model are presented together with discussions on the conditions under which the real time decision rule provides more cost savings over the traditional systems.
Service Systems and Service Management, 2008 International Conference on;
