Vein patterning by tissue-specific auxin transport

Unlike in animals, in plants, vein patterning does not rely on direct cell-cell interaction and cell migration; instead, it depends on the transport of the plant hormone auxin, which in turn depends on the activity of the PIN-FORMED1 (PIN1) auxin transporter. The current hypotheses of vein patterning by auxin transport propose that, in the epidermis of the developing leaf, PIN1-mediated auxin transport converges to peaks of auxin level. From those convergence points of epidermal PIN1 polarity, auxin would be transported in the inner tissues where it would give rise to major veins. Here, we have tested predictions of this hypothesis and have found them unsupported: epidermal PIN1 expression is neither required nor sufficient for auxin transport-dependent vein patterning, whereas inner-tissue PIN1 expression turns out to be both required and sufficient for auxin transport-dependent vein patterning. Our results refute all vein patterning hypotheses based on auxin transport from the epidermis and suggest alternatives for future tests

Nanoscale Cathodoluminescence Spectroscopy Probing the Nitride Quantum Wells in an Electron Microcope

To gain a deeper understanding of the luminescence of multiquantum wells and the factors affecting it on a microscopic level, cathodoluminescence combined with scanning transmission electron microscopy and spectroscopy was used to reveal the luminescence of In0.15Ga0.85N five-period multiquantum wells. The composition-wave-energy relationship was established in combination with energy-dispersive X-ray spectroscopy , and the bandgaps of In0.15Ga0.85N and GaN in multiple quantum wells were extracted by electron energy loss spectroscopy to understand the features of cathodoluminescence luminescence spectra. The luminescence differences between different periods of multiquantum wells and the effects on the luminescence of multiple quantum wells owing to defects such as composition fluctuation and dislocations were revealed. Our study establishing the direct correspondence between the atomic structure of InxGa1-xN multiquantum wells and photoelectric properties, provides useful information for nitride applications.Comment: 13 pages,4 figure

Nicotine Overrides DNA Damage-Induced G1/S Restriction in Lung Cells

As an addictive substance, nicotine has been suggested to facilitate pro-survival activities (such as anchorage-independent growth or angiogenesis) and the establishment of drug resistance to anticancer therapy. Tobacco smoking consists of a variety of carcinogens [such as benzopyrene (BP) and nitrosamine derivatives] that are able to cause DNA double strand breaks. However, the effect of nicotine on DNA damage-induced checkpoint response induced by genotoxins remains unknown. In this study, we investigated the events occurred during G1 arrest induced by γ-radiation or BP in nicotine-treated murine or human lung epithelial cells. DNA synthesis was rapidly inhibited after exposure to γ-radiation or BP treatment, accompanied with the activation of DNA damage checkpoint. When these cells were co-treated with nicotine, the growth restriction was compromised, manifested by upregulation of cyclin D and A, and attenuation of Chk2 phosphorylation. Knockdown of cyclin D or Chk2 by the siRNAs blocked nicotine-mediated effect on DNA damage checkpoint activation. However, nicotine treatment appeared to play no role in nocodazole-induced mitotic checkpoint activation. Overall, our study presented a novel observation, in which nicotine is able to override DNA damage checkpoint activated by tobacco-related carcinogen BP or γ-irradiation. The results not only indicates the potentially important role of nicotine in facilitating the establishment of genetic instability to promote lung tumorigenesis, but also warrants a dismal prognosis for cancer patients who are smokers, heavily exposed second-hand smokers or nicotine users

Objective Management and Assessment on Special Equipments Security - A Case Study of Elevators Security

Under the era of globalization, as China's rapid economic development, the amount of special equipments has been in the dramatic increase, which has brought a major challenge on how to ensure the safety in special equipments. The overall security situation in special equipments in China is not optimistic. This dissertation takes elevators as a case study to build the dynamic security administration model of special equipments, make an assessment on the model and analyze the model under different social circumstances of state level and global level. In this article the dynamic security administration model is created to achieve the management objective --- safety, based on the analysis and study of various processes and management entities of elevators, effectively making use of social resources to tighten the control over special equipments manufacture, installation, maintenance, operation, inspection, and supervision. AHP is used to determine assessment factors of multi-level analysis and weight of all factors. And it takes Fuzzy mathematic method to calculate assessment result, pointing out factors with existing issues, which can be rectified and perfected by continuous improvement. We also try to analyze the influence of five social environment factors: government administration, market economy, information technology, education and regulations on special equipments safe administration. Then we compare the differences of this model applying to Sweden and global level

Re-designing the Web’s Access Control System

Part 1: Invited PapersInternational audienceThe Web is playing a very important role in our lives, and is becoming an essential element of the computing infrastructure. With such a glory come the attacks–the Web has become criminals’ preferred targets. Web-based vulnerabilities now outnumber traditional computer security concerns. Although various security solutions have been proposed to address the problems on the Web, few have addressed the root causes of why web applications are so vulnerable to these many attacks. We believe that the Web’s current access control models are fundamentally inadequate to satisfy the protection needs of today’s web, and they need to be redesigned. In this extended abstract, we explain our position, and summarize our efforts in redesigning the Web’s access control systems

Bureaucratic protocols for secure two-party sorting, selection, and permuting

In this paper, we introduce a framework for secure two-party (S2P) computations, which we call bureaucratic computing, and we demonstrate its efficiency by designing practical S2P computations for sorting, selection, and random permutation. In a nutshell, the main idea behind bureaucratic computing is to design data-oblivious algorithms that push all knowledge and influence of input values down to small black-box circuits, which are simulated using Yao’s garbled paradigm. The practical benefit of this approach is that it maintains the zero-knowledge features of secure two-party computations while avoiding the significant computational overheads that come from trying to apply Yao’s garbled paradigm to anything other than simple two-inpu

Synthetic Lethality Induced by Loss of PKC δ and Mutated Ras

Synthetic lethal interaction between oncogenic Ha-ras and loss of PKC has been demonstrated. Recently, the authors reported that the concurrent knockdown of PKC α and β, via upregulating PKC δ, sensitizes cells with aberrant Ras signaling to apoptosis. As a continuation of the study, using shRNA, the authors demonstrate that loss of PKC δ causes a lethal reaction in NIH3T3/Hras or prostate cancer DU145 cells that overexpress JNK. In this apoptotic process, PKC α and β are upregulated and then associated with RACK1 (an adaptor for activated PKC) and JNK. Immunoblotting analysis shows that JNK is phosphorylated, accompanied with caspase 8 cleavage. The inhibition of JNK abrogates this apoptotic process triggered by PKC δ knockdown. Interestingly, without blocking PKC δ, the concurrent overexpression of wt- or CAT-PKC α and β is insufficient to induce apoptosis in the cells. Together with the authors’ previous findings, the data suggest that PKC α/β and δ function oppositely to maintain a balance that supports cells expressing v-ras to survive and prevents them from being eliminated through oncogenic stress-induced apoptosis

Contribution of the Locus of Heat Resistance to Growth and Survival of Escherichia coli at Alkaline pH and at Alkaline pH in the Presence of Chlorine

The locus of heat resistance (LHR) confers resistance to extreme heat, chlorine and oxidative stress in Escherichia coli. This study aimed to determine the function of the LHR in maintaining bacterial cell envelope homeostasis, the regulation of the genes comprising the LHR and the contribution of the LHR to alkaline pH response. The presence of the LHR did not affect the activity of the Cpx two-component regulatory system in E. coli, which was measured to quantify cell envelope stress. The LHR did not alter E. coli MG1655 growth rate in the range of pH 6.9 to 9.2. However, RT-qPCR results indicated that the expression of the LHR was elevated at pH 8.0 when CpxR was absent. The LHR did not improve survival of E. coli MG1655 at extreme alkaline pH (pH = 11.0 to 11.2) but improved survival at pH 11.0 in the presence of chlorine. Therefore, we conclude that the LHR confers resistance to extreme alkaline pH in the presence of oxidizing agents. Resistance to alkaline pH is regulated by an endogenous mechanism, including the Cpx envelope stress response, whereas the LHR confers resistance to extreme alkaline pH only in the presence of additional stress such as chlorine