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The stemness of bone marrow mesenchymal stem cells (BMSCs) is maintained by hypoxia. The oxygen level increases from vessel-free cartilage to hypoxic bone marrow and, furthermore, to vascularized bone, which might direct the chondrogenesis to osteogenesis and regenerate the skeletal system. Hence, oxygen was diffused from relatively low to high levels throughout a three-dimensional chip. When we cultured BMSCs in the chip and implanted them into the rabbit defect models of low-oxygen cartilage and high-oxygen calvaria bone, (i) the low oxygen level (base) promoted stemness and chondrogenesis of BMSCs with robust antioxidative potential; (ii) the middle level (two times ≥ low) pushed BMSCs to quiescence; and (iii) the high level (four times ≥ low) promoted osteogenesis by disturbing the redox balance and stemness. Last, endochondral or intramembranous osteogenesis upon transition from low to high oxygen in vivo suggests a developmental mechanism–driven solution to promote chondrogenesis to osteogenesis in the skeletal system by regulating the oxygen environment.

The dicentric chromosome assay (DCA) is considered the gold standard for radiation biodosimetry, but it is limited by its long dicentric scoring time and need for skilled scorers. The automation of scoring dicentrics has been considered a strategy to overcome the constraints of DCA. However, the studies on automated scoring methods are limited compared to those on conventional manual DCA. Our study aims to assess the performance of a semi-automated scoring method for DCA usingex vivoandin vivoirradiated samples. Dose estimations of 39 blind samples irradiatedex vivoand 35 industrial radiographers occupationally exposedin vivowere estimated using the manual and semi-automated scoring methods and subsequently compared. The semi-automated scoring method, which removed the false positives of automated scoring using the dicentric chromosome (DC) scoring algorithm, had an accuracy of 94.9% in theex vivoirradiated samples. It also had more than 90% accuracy, sensitivity, and specificity to distinguish binary dose categories reflecting clinical, diagnostic, and epidemiological significance. These data were comparable to those of manual DCA. Moreover, Cohen's kappa statistic and McNemar's test showed a substantial agreement between the two methods for categorizingin vivosamples into never and ever radiation exposure. There was also a significant correlation between the two methods. Despite of comparable results with two methods, lower sensitivity of semi-automated scoring method could be limited to assess various radiation exposures. Taken together, our findings show the semi-automated scoring method can provide accurate dose estimation rapidly, and can be useful as an alternative to manual DCA for biodosimetry in large-scale accidents or cases to monitor radiation exposure of radiation workers.

Purpose Mutual cooperation of biodosimetry laboratories is required for dose assessments of large numbers of people with potential radiation exposure, as in mass casualty accidents. We launched an intercomparison exercise to validate the performance of biodosimetry laboratories in South Korea. Materials and methods Participating laboratories shared metaphase images from dicentric chromosome assays (DCAs) and fluorescence in situ hybridization (FISH)-based translocation assays, which were evaluated based on their own scoring protocols. Results Overall, the coefficient of variation among three laboratories was less than 10% for counting scorable metaphases and chromosomal aberrations. However, there was variation in the interpretation of the International Atomic Energy Agency guidelines for selecting scorable metaphases and identifying chromosomal aberrations. In a technical workshop, scoring discrepancies were extensively discussed in order to harmonize biodosimetry protocols in Korea. In addition, metaphase images with agreement among all participating laboratories were compiled into an image databank, which can be used for education and training of scorers. Conclusions These findings and exercises may improve the accuracy of dose assessment, as well as increase the capacity for biodosimetry in South Korea.

Using data from 19 countries over the 1990–2015 period, we examine how economic policy uncertainty (EPU) affects accounting quality. We find that accounting quality, measured based on Nikolaev's (2018) model, increases during periods of high policy uncertainty. This relation is confirmed by the negative association between EPU and performance-adjusted discretionary accruals in a multivariate setting, and it extends to various alternative measures of earnings properties. We also find that the positive relation between EPU and accounting quality is more pronounced for government-dependent firms and firms with higher political risk. Additional analyses based on institutional investors' trading behavior, media freedom, and press circulation suggest that market participants' attention is a mechanism through which EPU affects accounting quality. Further, we find evidence that high accounting quality can mitigate the negative effects of EPU on corporate investment and valuation. Data Availability: All data are publicly available from sources indicated in the text.

All-in-one treatments represent a paradigm shift in future medicine. For example, inflammatory bowel disease (IBD) is mainly diagnosed by endoscopy, which could be applied for not only on-site monitoring but also the intestinal lesion-targeted spray of injectable hydrogels. Furthermore, molecular conjugation to the hydrogels would program both lesion-specific adhesion and drug-free therapy. This study validated this concept of all-in-one treatment by first utilizing a well-known injectable hydrogel that underwent efficient solution-to-gel transition and nanomicelle formation as a translatable component. These properties enabled spraying of the hydrogel onto the intestinal walls during endoscopy. Next, peptide conjugation to the hydrogel guided endoscopic monitoring of IBD progress upon adhesive gelation with subsequent moisturization of inflammatory lesions, specifically by nanomicelles. The peptide was designed to mimic the major component that mediates intestinal interaction with

In this study, quality keywords of frequent mention of failures were extracted by analyzing the field operational data of main battle tanks recorded for about 5 years. As a result of the data analysis, the leaf spring assembly of the crew hatches corrosion and failure was frequently occurred. FEA(Finite Element Analysis) and tests were performed to analyze the cause of the failure, and it was confirmed that durability of the leaf spring was insufficient. Therefore a design modification study was conducted to improve durability of the leaf spring, and FEA and durability tests demonstrated the improvement. As a result, the durability of leaf spring was improved at least 3.3 times compared to before improvement. This study will contribute to suggesting the use of data analysis in the defense area and improving the operability of the main battle tanks.

Threshold homomorphic encryption (Threshold HE) schemes are modified homomorphic encryption schemes to be suitable for privacy-preserving data integration and analysis. In actual usage of it, one should take it care into consideration who manages secret keys. In Eurocrypt 2012, Asharov et al. proposed decentralized $(n,n)$ -threshold HE schemes in bottom-up approach for which all $n$ parties must allow by doing a partial decryption to decrypt successfully a ciphertext. To support more general threshold structure for HE, Boneh et al. presented $(t, n)$ -threshold HE schemes using secret sharing schemes in top-down approach with a central key dealer. In this article, decentralized $(t, n)$ -threshold HE schemes in bottom-up approach will be constructed. The decentralized $(n,n)$ -threshold HE scheme is fisrt modified to reduce the error contained in the common evaluation key which affects to the entire parameter size. Then by applying $(t,n)$ -threshold secret sharing scheme, $(n,n)$ -threshold HE scheme is converted to $(t,n)$ -threshold HE scheme. Moreover, proactive secret sharing scheme is applied to update secret key share of the constructed $(t,n)$ -threshold HE scheme whenever needed.

In this article, we propose single-trace side-channel attacks against lattice-based key encapsulation mechanisms (KEMs) that are the third-round candidates of the national institute of standards and technology (NIST) standardization project. Specifically, we analyze the message encoding operation in the encapsulation phase of lattice-based KEMs to obtain an ephemeral session key. We conclude that a single-trace leakage implies a whole key recovery: the experimental results realized on a ChipWhisperer UFO STM32F3 target board achieve a success rate of 100% for $\mathsf {CRYSTALS-KYBER}$ and $\mathsf {SABER}$ regardless of an optimization level and those greater than 79% for $\mathsf {FrodoKEM}$ . We further demonstrate that the proposed attack methodologies are not restricted to the above algorithms but are widely applicable to other NIST post-quantum cryptography (PQC) candidates, including $\mathsf {NTRU Prime}$ and $\mathsf {NTRU}$ .

The $\mathsf {Rasta}$ cipher, proposed by Dobraunig et al. (CRYPTO 2018), is an HE-friendly cipher enjoying the fewest ANDs per bit and the lowest ANDdepth among the existing ciphers. A novel feature of $\mathsf {Rasta}$ is that its affine layers are freshly and randomly generated for every encryption. In this paper, we propose a new variant of $\mathsf {Rasta}$ , dubbed $\mathsf {Masta}$ . Similarly to $\mathsf {Rasta}$ , $\mathsf {Masta}$ takes as input a (master) secret key and a nonce, and generates a keystream block for each counter. On the other hand, $\mathsf {Masta}$ has two main differences from $\mathsf {Rasta}$ : $\mathsf {Masta}$ uses modular arithmetic to support HE schemes over a non-binary plaintext space, and it uses a smaller number of random bits in the affine layers by defining them with finite field multiplication. In this way, $\mathsf {Masta}$ outperforms $\mathsf {Rasta}$ in a transciphering framework with $\mathsf {BGV}/ \mathsf {FV}$ -style HE schemes. Our implementation shows that $\mathsf {Masta}$ is 505 to 592 times faster in terms of the throughput on the client-side, while 4792 to 6986 times faster on the server-side.

Background: The ginsenoside Rg3, one of active components of red ginseng, has chemopreventive and anticancer potential. Cancer stem cells retain self-renewal properties which account for cancer recurrence and resistance to anticancer therapy. In our present study, we investigated whether the standardized Korean Red Ginseng extract (RGE) and Rg3 could modulate the manifestation of breast cancer stem cell–like features through regulation of self-renewal activity. Methods: The effects of RGE and Rg3 on the proportion of CD44high/CD24low cells, as representative characteristics of stem-like breast cancer cells, were determined by flow cytometry. The mammosphere formation assay was performed to assess self-renewal capacities of breast cancer cells. Aldehyde dehydrogenase activity of MCF-7 mammospheres was measured by the ALDEFLUOR assay. The expression levels of Sox-2, Bmi-1, and P-Akt and the nuclear localization of hypoxia inducible factor-1α in MCF-7 mammospheres were verified by immunoblot analysis. Results: Both RGE and Rg3 decreased the viability of breast cancer cells and significantly reduced the populations of CD44high/CD24low in MDA-MB-231 cells. RGE and Rg3 treatment attenuated the expression of Sox-2 and Bmi-1 by inhibiting the nuclear localization of hypoxia inducible factor-1α in MCF-7 mammospheres. Suppression of the manifestation of breast cancer stem cell–like properties by Rg3 was mediated through the blockade of Akt-mediated self-renewal signaling. Conclusion: This study suggests that Rg3 has a therapeutic potential targeting breast cancer stem cells. Keywords: Breast cancer stem cells, Ginseng, Ginsenoside Rg3, Red ginseng extract, Self-renewal

The current paradigm of cancer medicine focuses on patient‐ and/or cancer‐specific treatments, which has led to continuous progress in the development of patient representatives (e.g., organoids) and cancer‐targeting carriers for drug screening. As breakthrough concepts, i) living cancer tissues convey intact profiles of patient‐specific microenvironmental signatures. ii) The growth mechanisms of cancer mass with intense cell‐cell interactions can be harnessed to develop self‐homing nano‐targeting by using cancer cell‐derived nanovesicles (CaNVs). Hence, a tissueoid model of ovarian cancer (OC) is developed by culturing OC patient tissues in a 3D gel chip, whose microchannel networks enable perfusion to maintain tissue viability. A novel model of systemic cancer responses is approached by xenografting OC tissueoids into ischaemic hindlimbs in nude mice. CaNVs are produced to carry general chemotherapeutics or new drugs under pre/clinical studies that target the BRCA mutation or energy metabolism, thereby increasing the test scope. This pioneer study cross‐validates drug responses from the OC clinic, tissueoid, and animal model by demonstrating the alignment of results in drug type‐specific efficiency, BRCA mutation‐dependent drug efficiency, and metabolism inhibition‐based anti‐cancer effects. Hence, this study provides a directional foundation to accelerate the discovery of patient‐specific drugs with CaNV application towards future precision medicine., A microchannel chip enables direct perfusion culture of ovarian cancer tissues from patients. Consequently, drug efficacies are cross‐validated with animal and clinical outcomes towards patient‐specific medicine. Considering spontaneous cancer cell aggregation upon propagation, cancer cell‐derived nanoparticles are produced to program self‐homing to target cancer sites. Loading of metabolic inhibitors to the particles represents a “trojan horse”‐like strategy.

Caveolin-1 (Cav-1), a major structural component of cell membrane caveolae, is involved in a variety of intracellular signaling pathways as well as transmembrane transport. Cav-1, as a scaffolding protein, modulates signal transduction associated with cell cycle progression, cellular senescence, cell proliferation and death, lipid homeostasis, etc. Cav-1 is also thought to regulate the expression or activity of oncoproteins, such as Src family kinases, H-Ras, protein kinase C, epidermal growth factor, extracellular signal-regulated kinase, and endothelial nitric oxide synthase. Because of its frequent overexpression or mutation in various tumor tissues and cancer cell lines, Cav-1 has been speculated to play a role as an oncoprotein in cancer development and progression. In contrast, Cav-1 may also function as a tumor suppressor, depending on the type of cancer cells and/or surrounding stromal cells in the tumor microenvironment as well as the stage of tumors.

Engineered ovary mimetics enable hormone autocrination and restore ovarian functions with reduction of menopause risks., The regeneration potential of implantable organ model hydrogels is applied to treat a loss of ovarian endocrine function in women experiencing menopause and/or cancer therapy. A rat ovariectomy model is used to harvest autologous ovary cells while subsequently producing a layer-by-layer form of follicle spheroids. Implantation of a microchannel network hydrogel with cell spheroids [vascularized hydrogel with ovarian spheroids (VHOS)] into an ischemic hindlimb of ovariectomized rats significantly aids the recovery of endocrine function with hormone release, leading to full endometrium regeneration. The VHOS implantation effectively suppresses the side effects observed with synthetic hormone treatment (i.e., tissue overgrowth, hyperplasia, cancer progression, deep vein thrombosis) to the normal levels, while effectively preventing the representative aftereffects of menopause (i.e., gaining fatty weight, inducing osteoporosis). These results highlight the unprecedented therapeutic potential of an implantable VHOS against menopause and suggest that it may be used as an alternative approach to standard hormone therapy.

Cancer stem cells (CSCs) constitute a subpopulation of transformed cells that possess intrinsic ability to undergo selfrenewal and differentiation, which drive tumour resistance and cancer recurrence. It has been reported that CSCs possess enhanced protection against oxidative stress induced by reactive oxygen species compared with nonstem-like cancer cells. In the present work, we investigated the role of heme oxygenase-1 (HO-1), a representative antioxidant enzyme, on the stemness and selfrenewal of human breast CSCs. We found that pharmacologic or genetic inhibition of HO-1 attenuated the sphere formation, whereas HO-1 inducers enhanced the number and the size of tumourspheres in breast CSCs. Carbon monoxide (CO) is endogenously generated as a consequence of degradation of heme by HO-1. The proportion of populations of CD44+/CD24- cells retaining CSC properties was increased in MDA-MB-231 cells treated with a CO-releasing molecule (CORM-2). Following CORM-2 treatment, the expression of Notch-1 and related genes Jagged-1 and Hes1 was increased, which was accompanied by the mammosphere formation. Taken together, these findings suggest that HO-1-derived CO production stimulates the formation of mammospheres in breast cancer cells through activation of Notch-1 signalling.

Caveolin-1 (Cav-1), a major structural component of cell membrane caveolae, is involved in a variety of intracellular signaling pathways as well as transmembrane transport. Cav-1, as a scaffolding protein, modulates signal transduction associated with cell cycle progression, cellular senescence, cell proliferation and death, lipid homeostasis, etc. Cav-1 is also thought to regulate the expression or activity of oncoproteins, such as Src family kinases, H-Ras, protein kinase C, epidermal growth factor, extracellular signal-regulated kinase, and endothelial nitric oxide synthase. Because of its frequent overexpression or mutation in various tumor tissues and cancer cell lines, Cav-1 has been speculated to play a role as an oncoprotein in cancer development and progression. In contrast, Cav-1 may also function as a tumor suppressor, depending on the type of cancer cells and/or surrounding stromal cells in the tumor microenvironment as well as the stage of tumors.

Overproduction of prostaglandin E2 (PGE2) has been linked to enhanced tumor cell proliferation, invasiveness and metastasis as well as resistance to apoptosis. 15-Keto prostaglandin E2 (15-keto PGE2), a product formed from 15-hydroxyprostaglandin dehydrogenase-catalyzed oxidation of PGE2, has recently been shown to have anti-inflammatory and anticarcinogenic activities. In this study, we observed that 15-keto PGE2 suppressed the phosphorylation, dimerization and nuclear translocation of signal transducer and activator of transcription 3 (STAT3) in human mammary epithelial cells transfected with H-ras (MCF10A-ras). 15-Keto PGE2 inhibited the migration and clonogenicity of MCF10A-ras cells. In addition, subcutaneous injection of 15-keto PGE2 attenuated xenograft tumor growth and phosphorylation of STAT3 induced by breast cancer MDA-MB-231 cells. However, a non-electrophilic analogue, 13,14-dihydro-15-keto PGE2 failed to inhibit STAT3 signaling and was unable to suppress the growth and transformation of MCF10A-ras cells. These findings suggest that the α,β-unsaturated carbonyl moiety of 15-keto PGE2 is essential for its suppression of STAT3 signaling. We observed that the thiol reducing agent, dithiothreitol abrogated 15-keto PGE2-induced STAT3 inactivation and disrupted the direct interaction between 15-keto PGE2 and STAT3. Furthermore, a molecular docking analysis suggested that Cys251 and Cys259 residues of STAT3 could be preferential binding sites for this lipid mediator. Mass spectral analysis revealed the covalent modification of recombinant STAT3 by 15-keto PGE2 at Cys259. Taken together, thiol modification of STAT3 by 15-keto PGE2 inactivates STAT3 which may account for its suppression of breast cancer cell proliferation and progression., Highlights • 15-Keto-prostaglandin E2 inhibits activation of STAT3 in MCF10A-ras cells. • 15-Keto-prostaglandin E2 suppresses the growth and transformation of MCF10A-ras cells. . • 15-Keto-prostaglandin E2 attenuated xenograft tumor growth and STAT3 phosphorylation. . • 15-Keto PGE2 modulates STAT3 by directly binding to its Cys259 residue.

Cancer stem cells (CSCs) are responsible for tumor initiation, metastasis and recurrence. Caveolin-1 (Cav-1) is a major protein of caveolae, which participates in various cellular functions, such as vesicle trafficking, cholesterol homeostasis, tumor progression, etc. In the present study, we investigated a role for Cav-1 in regulating the stemness of human breast cancer (MDA-MB-231) cells. Cav-1 expression was significantly lower in tumorspheres than in adherent cells. The silencing of Cav-1 enhanced stemness of MDA-MB-231 cells. Mechanistically, Cav-1 silencing was accompanied by enhanced expression of Bmi-1, which is a representative self-renewal regulator, and promoted epithelial-mesenchymal transition. In a CSC-like state, reduced Cav-1 depends on its destabilization through ubiquitin-proteasome degradation. We further found that Src-mediated phosphorylation of Cav-1 at the Tyr 14 residue is essential for its degradation. Taken together, these findings suggest that Cav-1 destabilization by Src may play a pivotal role in manifestation and maintenance of stemness in breast cancer cells.

Uterine fibroids the most common benign gynecological tumors that can cause abnormal menstrual bleeding, menstrual cramps, pelvic discomfort, infertility, urinary frequency and others. Although surgical removal of the uterus is the definitive treatment, some patients choose to keep their uterus in place. For this reason, minimally invasive treatment options have been suggested such as uterine artery occlusion, high-frequency ablation and others.1 However, these interventions are still in the experimental phase.

Polymer-supported NHC–metal catalysts were prepared from chloromethyl polystyrene resin via two-step reaction. Metals were loaded into 1.6 – 16 mol% of total imidazolium and the remaining imidazolium chloride salt provided ionic liquid moiety. The formation of metal complex with the polymer-supported NHC ligand was analyzed by ATR FT-IR, XRD, and XPS. The synthesized polymer-supported NHC–metal catalysts were applied to the dehydration of fructose into HMF. The environmentally benign and inexpensive polymer-supported NHC–FeIII catalyst showed good catalytic activity and yielded HMF at 73% (with a conversion of 97%). It could also be reused without significant loss of catalytic activity.

Silver nanomaterials have been extensively investigated due to their unique optical and biological properties. Surface plasmons and scattering phenomena occurring on silver nanostructures can provide useful analytical or sensor platform. Here, we present silver nanoparticles preferentially reduced on polyethylene glycol (PEG)-grafted glass surfaces for application to surface-enhanced Raman scattering (SERS). Uniform silver nanoparticles of ∼50 nm size were easily generated by dipping the PEG-grafted glass surfaces in silver salt solution at room temperature without any additional reducing agent. The silver nanoparticles generated on the PEG-grafted surfaces were confirmed by AFM and FE-SEM analysis.

This paper describes a temperature-controllable bead affinity chromatography (BAC) in a microsystem for biomarker detection, and preparing samples for matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) analysis. Cancer marker proteins were captured in the microsystem by BAC with RNA aptamer-immobilized microbeads. The captured proteins were then denatured and released from the microbeads by controlling temperature. The microsystem consists of a microreactor for trapping microbeads and a temperature control unit for thermal treatment of the trapped beads. We used polymethylsilxoane or single crystalline silicon in fabricating two different types of reaction chamber to compare the differences in performance originated from the materials. Carcinoembryonic antigen was concentrated and purified from human serum using the microsystem and detected by MALDI-TOF MS to demonstrate the usefulness of the microsystem. The microsystem simplifies a sample preparation process required for protein analysis and cancer biomarker detection, which will accelerate the process of cancer research.

This study analyzes taxi driver`s risk-taking propensity with respect to risk-taking behaviour and traffic locus of control. In order to explore the traffic risk-taking, we present a predictive model by structural analysis of driver`s risk-taking propensity. By applying this model to survey data from taxi drivers, we can observe that driver`s risk-taking propensity has a significant impact on the traffic violation intention, and the higher perception of law and the lower lack of law-abiding drivers have, the more they tend to violate. Second, we test using multivariate analysis if the level of risk-taking propensity differs by the locus of control( external or internal). Drivers of external control shows higher risk-taking level compared to those of internal control so that the risk-taking propensity shows difference according to the locus of control for the responsibility of traffic accidents. The structural equation model of our study yielded

The purpose of this study was to determine the effects of the duration of frying and storage periods on physicochemical characteristics of various oils using at home. The materials used for the study consisted of four kinds of vegetable oils: soybean, canola, extra virgin olive and pure olive oils, and shortening. Chicken breasts were fried in oils heated at 180 ℃. The oils were stored with or without filtering and reused 3 times, during the 10 day period. The extra virgin and pure olive oils showed higher acid, peroxide value and yellowness than the other oils (p

Polytetrafluoroethylene (PTFE, Teflon), a frequently utilized polymer for the fabrication of synthetic vascular graft, was surface-modified by electron beam irradiation. At the same time, the silver nanostructures were obtained on PTFE surface when exposed to an electron beam in silver ion solution. Results from FE-SEM characterization revealed that morphologies of the prepared silver nanostructures were in different shapes and sizes. The effect of electron beam current and the irradiation time on silver nanostructures formations were also investigated. In addition, we found that these prepared silver nanostructures on PTFE surface exhibited antimicrobial effect through qualitative evaluation method against Escherichia coli (ATCC 8739). This approach offered a new route for preparing silver nanostructures under electron beam irradiation, and the resulting PTFE vascular graft could be used as biocidal medical device.

Macroporous polymer beads have been used in various fields, for example as solid supports in solid-phase organic synthesis and heterogeneous catalysts and as adsorbents in column chromatography. Their broad applications have stimulated many researchers to develop various kinds of macroporous polymer beads. However, despite all the efforts, it is still hard to control the porosity and pore size distributions within the polymer beads. In this study, we prepared pore size controllable macroporous poly(methyl methacrylate-co-methyl methacrylic acid) (PMMA-co-PMAA) beads. First, we prepared silica submicron particles embedded PMMA beads by the polymerization of methyl methacrylate monomer with mono-dispersed silica particles. Then, the silica NP embedded PMMA beads were hydrolyzed with sodium hydroxide to obtain a macroporous structure by removing the embedded silica particles. At the same time, part of the methyl methacrylate turned into methacrylic acid, which caused the PMMA beads to become PMAA-co-PMMA beads. Through this method, two types of beads having different pore sizes were prepared as a model study. The pore size of the beads could be easily controlled by adjusting the size of the silica particles.

5-Hydroxymethyl-2-furfural (HMF) was selectively converted to 2,5-diformylfuran (DFF) under mild conditions by polymer-supported IBX amide reagent, thus providing a new platform for the production of highly valuable chemicals from biomass.

A new type of magnetite/silica nanoparticle-supported N-heterocyclic carbene nickel catalyst (Mag-NHC-Ni) was developed from imidazolium with N-picolyl moieties and used as an efficient catalyst in the C―S coupling of various aryl halides with thiols. Moreover, the catalyst was easily recovered from the reaction mixture by simple filtration and recycled with almost consistent activity.

We propose a new notion of metered signatures. Metered signature is an extension of k-times signatures in which a signer can generate only k signatures. However, the restriction of metered signatures can be more elaborate: It can be used k-times every day or to preserve the order of signed messages in some applications. Any violation of this regulation reveals a secret key or the signature on a predetermined message. The applications includes proxy signatures, limited free downloads, and the rating web site. We give two instances of metered signatures: One is based on the computational Diffie-Hellman problem (CDHP) using a bilinear map and the other is based on the RSA problem. In both schemes, the signature and certificate size and the verification cost are constant with respect to k. Further, we show that the proposed metered signatures admit batch verification of many signatures almost at one verification cost with small security loss.

To mitigate TOT complications we designed a modified TOT technique called canal TOT. We describe this new technique and evaluate its feasibility.Between October 2006 and June 2007, 105 consecutive women with stress urinary incontinence underwent a canal TOT procedure. Two oblique lateral incisions were made in the anterior vaginal wall and a suburethral canal was created between the incisions. Mesh was transferred beneath the canal. The subsequent canal TOT surgical steps were identical to those of the original TOT procedure. All patients were evaluated by urological examination and self-assessment questionnaires (Incontinence Impact Questionnaire-Short Form and Urogenital Distress Inventory-Short Form) preoperatively and 12 months postoperatively. Reportedly dyspareunia developed after the operation.A minimum 1-year followup was available in 99 patients. Median operative time was 25 minutes (range 15 to 50). No mesh erosion, retropubic hematoma or complete bladder retention developed. Transient postoperative voiding dysfunction and transient de novo urgency were observed in 2 (2.0%) and 8 patients (8.1%), respectively. Dyspareunia developed after surgery in 4 patients (4.0%). Postoperatively Incontinence Impact Questionnaire-Short Form and Urogenital Distress Inventory-Short Form scores decreased significantly (p0.05). Objective and subjective cure rates were 98.0% and 89.9%, respectively.The canal TOT procedure is feasible and effective for mitigating the complications of the original TOT procedure. This technique might be especially useful in patients with cystocele because of the paravaginal defect as well as in patients with obesity or prior vaginal surgery. However, a large-scale and long-term followup study is required to verify the effectiveness of this technique.

The element reduction of a multiset S is to reduce the number of repetitions of an element in S by a predetermined number. Privacy- preserving element reduction of a multiset is an important tool in private computation over multisets. It can be used by itself or by combination with other private set operations. Recently, an e-cient privacy-preserving element reduction method was proposed by Kissner and Song (7). In this paper, we point out a mathematical ∞aw in their polynomial representa- tion that is used for the element reduction protocol and provide its cor- rection. Also we modify their over-threshold set-operation protocol, using an element reduction with the corrected representation, which is used to output the elements that appear over the predetermined threshold num- ber of times in the multiset resulting from other privacy-preserving set operations.