• Molecules and Cells
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• v.39 no.8
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• pp.587-593
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• 2016

As sessile organisms, plants must be able to adapt to the environment. Plants respond to the environment by adjusting their growth and development, which is mediated by sophisticated signaling networks that integrate multiple environmental and endogenous signals. Recently, increasing evidence has shown that a bHLH transcription factor PIF4 plays a major role in the multiple signal integration for plant growth regulation. PIF4 is a positive regulator in cell elongation and its activity is regulated by various environmental signals, including light and temperature, and hormonal signals, including auxin, gibberellic acid and brassinosteroid, both transcriptionally and post-translationally. Moreover, recent studies have shown that the circadian clock and metabolic status regulate endogenous PIF4 level. The PIF4 transcription factor cooperatively regulates the target genes involved in cell elongation with hormone-regulated transcription factors. Therefore, PIF4 is a key integrator of multiple signaling pathways, which optimizes growth in the environment. This review will discuss our current understanding of the PIF4-mediated signaling networks that control plant growth.

• Korean Journal of Construction Engineering and Management
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• v.10 no.5
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• pp.37-46
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• 2009

This research will focus on the public agencies, designers, supervisors, building cooperation, and contractor who involved in urban development plan. By understanding the complexity and the priorities in urban development process, all problems of the urban development projects can be solved or improved. These priorities are specified using AHP (Analytic Hierarchy Process). A questionnaire survey is employed to identify the problems of urban development process and the methods of revitalizing urban in this research. Through the survey, 35 issues are drawn out. Factor analysis technique is applied to extract the underlying interrelationships possibly existing. Using latent root criterion and varimax rotation method, 9 factors are extracted(by using 34 issues after deleting 1 issue less than 0.4 of factor loading) These 9 factors named as PIF (Problem Improvement Factor) consist of integration estimation (PIF1), cooperation operation capability (PIF2), contractor corporation capability (PIF3), capital for infrastructure investment (PIF4), misunderstanding of effective land use (PIF5), financial capability (PIF6), obscure goal of project (PIF7), shortage of cooperation expertise (PIFS), administrative procedures (PIF9). PIF 6 is the most important factor and PIF 1 is the most widely effective factor to succeed urban land development projects. It is recognized that administrative office is most responsible for PIF1 cooperation is most responsible for PIF2, 7, 8 and 9; contractors is most responsible for PIF3 and PIF6; administrative agencies is most responsible for PIF4; cooperation and consultants are responsible for PIF5. From findings in this study, some suggestions are proposed for the revitalization methods of urban development projects through the land readjustment method.

• Radiation Oncology Journal
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• v.29 no.4
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• pp.269-276
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• 2011

Purpose: To determine the incidence, risk factors, and clinical characteristics of pelvic insufficiency fracture (PIF) in patients with cervical cancer. Materials and Methods: Between July 2004 and August 2009, 235 patients with non-metastatic cervical cancer were treated with definitive chemoradiation or postoperative radiotherapy. Among 235 patients, 117 (49.8%) underwent the first positron emission tomography/computed tomography (PET/CT) within 1 year after radiotherapy. The median radiation dose was 55 Gy (range, 45 to 60 Gy). Medical charts and imaging studies, including PET/CT, magnetic resonance imaging (MRI), CT. bone scintigraphy were reviewed to evaluate the patients with PIF. Results: Among 235 patients, 16 developed PIF. The 5-year detection rate of PIF was 9.5%. The 5-year detection rate of PIF in patients who underwent the first PET/CT within a year was 15.6%. The median time to development of PIF was 12.5 months (range, 5 to 30 months). The sites of fracture included 12 sacroiliac joints, 3 pubic rami, 3 iliac bones, and 1 femoral neck. Eleven of 16 patients having PIF complained of hip pain requiring medications. One patient required hospitalization for pain control. The significant risk factors of PIF were old age, body mass index less than 23, bone mineral density less than -3.5 SD, and the first PET/CT within a year after radiotherapy. Radiation dose and concurrent chemotherapy had no impact on PIF rate. Conclusion: PIFs were not rare after pelvic radiotherapy in cervical cancer patients in the era of PET/CT. Timely diagnosis and management of PIF can improve quality of life in patients with cervical cancer, in addition to reducing unnecessary medical expenses.

• Molecules and Cells
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• v.43 no.7
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• pp.645-661
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• 2020

Leaf senescence is a developmental process by which a plant actively remobilizes nutrients from aged and photosynthetically inefficient leaves to young growing ones by disassembling organelles and degrading macromolecules. Senescence is accelerated by age and environmental stresses such as prolonged darkness. Phytochrome B (phyB) inhibits leaf senescence by inhibiting phytochrome-interacting factor 4 (PIF4) and PIF5 in prolonged darkness. However, it remains unknown whether phyB mediates the temperature signal that regulates leaf senescence. We found the light-activated form of phyB (Pfr) remains active at least four days after a transfer to darkness at 20℃ but is inactivated more rapidly at 28℃. This faster inactivation of Pfr further increases PIF4 protein levels at the higher ambient temperature. In addition, PIF4 mRNA levels rise faster after the transfer to darkness at high ambient temperature via a mechanism that depends on ELF3 but not phyB. Increased PIF4 protein then binds to the ORE1 promoter and activates its expression together with ABA and ethylene signaling, accelerating leaf senescence at high ambient temperature. Our results support a role for the phy-PIF signaling module in integrating not only light signaling but also temperature signaling in the regulation of leaf senescence.

• Korean Medical Education Review
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• v.23 no.2
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• pp.80-89
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• 2021

Professional identity formation (PIF) is an essential concept in professional education. Many scholars have explored conceptual frameworks of PIF and conducted empirical studies to advance an understanding of the construct in medical education. Despite its importance, it is unclear what educational approaches and assessment practices are actually implemented in medical education settings. Therefore, we conducted a literature review of empirical studies reporting educational practices for medical learners' PIF. We searched the Web of Science database using keywords and chose 37 papers for analysis based on inclusion and exclusion criteria. Thematic analysis was conducted. Most empirical papers (92%) were from North America and Western Europe and used qualitative research methods, including mixed methods (99%). The papers reported the use of reflection activities and elective courses for specific purposes, such as art as an educational activity. Patient and healthcare experiences were also found to be a central theme in medical learners' PIF. Through an iterative analysis of the key themes that emerged from the PIF studies, we derived the following key concepts and implications: (1) the importance of creating informal and incidental learning environments, (2) ordinary yet authentic patient experiences, (3) a climate of psychosocial safety in a learning environment embracing individual learners' background and emotional development, and (4) the reconceptualization of PIF education and assessment. In conclusion, research on PIF should be diversified to include various cultural and social contexts. Theoretical frameworks should also be diversified and developed beyond Kegan's developmental framework to accommodate the nonlinear and dynamic nature of PIF.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.110-124
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• 1993

A Nonlinear model-based Hybrid Controller (NHC) is developed which consists of the adaptive proportional-integral-feedforward (PIF) gains and variable structure controller. The controller has the robustness against modeling uncertainty and is applied to the trajectory tracking control of single-input, single-output nonlinear systems. The essence of the scheme is to divide the control into four different terms. Namely, the adaptive P-I-F gains and variable structure controller are used to accomplish the specific control actions by each terms. The robustness of the controller is guaranteed by the feedback of estimated uncertainty and the performance specification given by the adaptation of PIF gains using the second method of Lyapunov. The variable structure controller is incorporated to regulate the initial peak of the tracking error during the parameter adaptation is not settled yet. The newly developed NHC method is applied to the power tracking control of a nuclear reactor and the simulation results show great improvement in tracking performance compared with the conventional model-based control methods.

• Food Science and Biotechnology
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• v.15 no.1
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• pp.152-157
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• 2006

Enterobacter sakazakii, designated as an unique microbial species in 1980, may cause bacteremia, necrotizing enterocolitis and infant meningitis. The distribution and the thermostability of E. sakazakii in unprocessed ready-to-eat (RTE) agricultural products of 252 and in 25 powdered infant formulas (PIF) were analyzed. Eighty one, 50, 43, and 47% of brown rice, pumpkin, potato, and carrot samples, respectively, had aerobic plate counts (ARC) in the range of 5 log CFU/g or more. Almost all the other products sampled had APC of approximately 2 log CFU/g. Fifty three, 75, 67, and 68% of banana, pumpkin, soybean, and carrot had Enterobacteriaceae counts approximating 3 log CFU/g. Sixty six percent of the brown rice tested had Enterobacteriaceae counts approximating 5-6 log CFU/g. E. sakazakii was isolated from 3/25(12%), 4/23(17%), 1/24(4%), and 1/27(4%) of PIF, brown rice, laver, and tomato samples, respectively. D-values were 3.52-4.79 min at 60 and $D_{60}-values$ were similar as the isolates reported. Thermal inactivation of four thermovariant E. sakazakii strains during the rehydration of PIF with hot water were investigated. At $50^{\circ}C$, the levels of E. sakazakii decreased one log CFU/g for 4-6 min and thereafter the levels remained stable for 20 min. At $60^{\circ}C$, inactivation by about 2 log CFU/g occurred for 20 min. Therefore, the unprocessed agricultural products might be a source of contamination for PIF when used as an ingredient after drying and pulverization. Rehydration of PIF for infant feeding with a water temperature of $60^{\circ}C$ rather than $50^{\circ}C$, as recommended by the manufacturers, may be helpful in the reduction of potential E. sakazakii risk.

• Journal of Dairy Science and Biotechnology
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• v.39 no.3
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• pp.113-120
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• 2021

Although the number of incidences of illness caused by ingestion of the bacterial pathogen Enterobacter sakazakii (Cronobacter spp.) has dramatically declined, there remains a need for a robust isolation method to recover this microbe from powdered infant formula (PIF). The current method described in the FDA's Bacteriological Analytical Manual requires multiple steps, and 3-4+ days for complete analysis of PIF isolated E. sakazakii (Cronobacter spp.). We describe a bacteriological method including a one-step enrichment followed by plating on chromogenic agar for presumptive identification of E. sakazakii (Cronobacter spp.). Suspected colonies are confirmed by either biochemical analyses, or a Real-Time PCR-based assay. Using this method, E. sakazakii (Cronobacter spp.) in PIF can be isolated and identified within one day (24 hours).

• Animal cells and systems
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• v.3 no.2
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• pp.103-113
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• 1999

Many in-depth reviews related to regulations of prolactin secretion are available. We will, therefore, focus on controversial aspects using personal opinion in this review. The neuroendocrine control of prolactin secretion from the anterior pituitary gland involves multiple factors including prolactin-release inhibiting factor (PIF) and prolactin releasing factor (PRF). The PIF exerts a tonic inhibitory control in the physiological conditions. The PIF should be able to effectively inhibit prolactin release or a lifetime, but the inhibitory action of dopamine cannot be sustained for a long period of time. Perifusion of a high concentration of dopamine (l ,000 nM) could not sustain inhibitory action on prolactin release but when a small amount of ascorbic acid (0.1 mM) is added in a low concentration of dopamine (3 nM) solution, prolactin release was inhibited for a long period. Ascorbate is essential for dopamine action to inhibit prolactin release. We have, therefore, concluded that the PIF is dopamine plus ascorbate. The major transduction system for dopamine to inhibit prolactin release is the adenylyl cyclase system. Dopamine decreases cyclic AMP concentration by inhibiting adenylyl cyclase, and cyclic AMP stimulates prolactin release. However, the inhibitory mechanism of dopamine on prolactin release is much more complex than simple inhibition of CAMP production. The dopamine not only inhibits cyclic AMP synthesis but also inhibits prolactin release by acting on a link(s) after the CAMP event in a chain reaction for inhibiting prolactin release. Low concentrations of dopamine stimulate prolactin release. Lactotropes are made of several different subtypes of cells and several different dopamine receptors are found in pituitary. The inhibitory and stimulatory actions induced by dopamine can be generated by different subtype of receptors. The GH$_4$ZR$_7$ cells express only the short isoform (D$_{2s}$) of the dopamine receptor, as a result of transfecting the D$_{2s}$ receptors into GH$_4$C$_1$ cells which do not express any dopamine receptors. When dopamine stimulates or inhibits prolactin release in GH$_4$ZR$_7$ cells, it is clear that the dopamine should act on dopamine D$_{2s}$ receptors since there is no other dopamine receptor in the GH$_4$ZR$_7$. Dopamine is able to stimulate prolactin release in a relatively low concentration while it inhibits in a high concentration in GH$_4$ZR$_7$. These observations indicate that the dopamine D$_2$ receptor can activate stimulatory and/or inhibitory transduction system depending upon dopamine concentrations.

• Korean Journal of Metals and Materials
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• v.50 no.2
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• pp.136-145
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• 2012

Resistance spot welding of TRIP780 steels was investigated to enhance understanding of weld fracture mode after tensile shear testing (TST) and L-shape tensile testing (LTT). The main failure mode for spot welds of TRIP780 steels was partial interfacial fracture (PIF). Although PIF does not satisfy the minimum button diameter (4${\surd}$t) for acceptable welds, it shows enough load carrying capacity of resistance spot welds for advanced high strength steels. In the analysis of displacement controlled L-shape tensile test results, cracks initiated at the notch of the faying surface and propagated through the interface of weldments, and finally, cracks change path into the sheet thickness direction. Use of the ductility ratio and CE analysis suggested that the occurrence of PIF is closely related to high hardness and brittle welds, which are caused by fast cooling rates and high chemical compositions of TRIP steels. Analysis of the hold time and weld time in a welding schedule demonstrated that careful control of the cooling rate and the size of a weld nugget and the HAZ zone can reduce the occurrence of PIF, which leads to sound welds with button fractures (BFs).