Can Variational Quantum Algorithms Demonstrate Quantum Advantages? Time Really Matters

Applying low-depth quantum neural networks (QNNs), variational quantum algorithms (VQAs) are both promising and challenging in the noisy intermediate-scale quantum (NISQ) era: Despite its remarkable progress, criticisms on the efficiency and feasibility issues never stopped. However, whether VQAs can demonstrate quantum advantages is still undetermined till now, which will be investigated in this paper. First, we will prove that there exists a dependency between the parameter number and the gradient-evaluation cost when training QNNs. Noticing there is no such direct dependency when training classical neural networks with the backpropagation algorithm, we argue that such a dependency limits the scalability of VQAs. Second, we estimate the time for running VQAs in ideal cases, i.e., without considering realistic limitations like noise and reachability. We will show that the ideal time cost easily reaches the order of a 1-year wall time. Third, by comparing with the time cost using classical simulation of quantum circuits, we will show that VQAs can only outperform the classical simulation case when the time cost reaches the scaling of $10^0$-$10^2$ years. Finally, based on the above results, we argue that it would be difficult for VQAs to outperform classical cases in view of time scaling, and therefore, demonstrate quantum advantages, with the current workflow. Since VQAs as well as quantum computing are developing rapidly, this work does not aim to deny the potential of VQAs. The analysis in this paper provides directions for optimizing VQAs, and in the long run, seeking more natural hybrid quantum-classical algorithms would be meaningful.Comment: 18 pages, 7 figure

NCP activates chloroplast transcription by controlling phytochrome-dependent dual nuclear and plastidial switches.

Phytochromes initiate chloroplast biogenesis by activating genes encoding the photosynthetic apparatus, including photosynthesis-associated plastid-encoded genes (PhAPGs). PhAPGs are transcribed by a bacterial-type RNA polymerase (PEP), but how phytochromes in the nucleus activate chloroplast gene expression remains enigmatic. We report here a forward genetic screen in Arabidopsis that identified NUCLEAR CONTROL OF PEP ACTIVITY (NCP) as a necessary component of phytochrome signaling for PhAPG activation. NCP is dual-targeted to plastids and the nucleus. While nuclear NCP mediates the degradation of two repressors of chloroplast biogenesis, PIF1 and PIF3, NCP in plastids promotes the assembly of the PEP complex for PhAPG transcription. NCP and its paralog RCB are non-catalytic thioredoxin-like proteins that diverged in seed plants to adopt nonredundant functions in phytochrome signaling. These results support a model in which phytochromes control PhAPG expression through light-dependent double nuclear and plastidial switches that are linked by evolutionarily conserved and dual-localized regulatory proteins

Use of electroporation and reverse iontophoresis for extraction of transdermal multibiomarkers

Congo Tak-Shing Ching1,2, Lin-Shien Fu3-5, Tai-Ping Sun1, Tzu-Hsiang Hsu1, Kang-Ming Chang21Department of Electrical Engineering, National Chi Nan University, Puli, Nantou County, 2Department of Photonics and Communication Engineering, Asia University, Wufeng, Taichung, 3Department of Pediatrics, National Yang Ming University, Taipei, 4Institute of Technology, National Chi Nan University, Puli, 5Department of Pediatrics, Taichung Veterans General Hospital, Taichung City, TaiwanBackground: Monitoring of biomarkers, like urea, prostate-specific antigen (PSA), and osteopontin, is very important because they are related to kidney disease, prostate cancer, and ovarian cancer, respectively. It is well known that reverse iontophoresis can enhance transdermal extraction of small molecules, and even large molecules if reverse iontophoresis is used together with electroporation. Electroporation is the use of a high-voltage electrical pulse to create nanochannels within the stratum corneum, temporarily and reversibly. Reverse iontophoresis is the use of a small current to facilitate both charged and uncharged molecule transportation across the skin. The objectives of this in vitro study were to determine whether PSA and osteopontin are extractable transdermally and noninvasively and whether urea, PSA, and osteopontin can be extracted simultaneously by electroporation and reverse iontophoresis.Methods: All in vitro experiments were conducted using a diffusion cell assembled with the stratum corneum of porcine skin. Three different symmetrical biphasic direct currents (SBdc), five various electroporations, and a combination of the two techniques were applied to the diffusion cell via Ag/AgCl electrodes. The three different SBdc had the same current density of 0.3 mA/cm2, but different phase durations of 0 (ie, no current, control group), 30, and 180 seconds. The five different electroporations had the same pulse width of 1 msec and number of pulses per second of 10, but different electric field strengths of 0 (ie, no voltage, control group), 74, 148, 296, and 592 V/cm. Before and after each extraction experiment, skin impedance was measured at 20 Hz.Results: It was found that urea could be extracted transdermally using reverse iontophoresis alone, and further enhancement of extraction could be achieved by combined use of electroporation and reverse iontophoresis. Conversely, PSA and osteopontin were found to be extracted transdermally only by use of reverse iontophoresis and electroporation with a high electrical field strength (>296 V/cm). After application of reverse iontophoresis, electroporation, or a combination of the two techniques, a reduction in skin impedance was observed.Conclusion: Simultaneous transdermal extraction of urea, PSA, and osteopontin is possible only for the condition of applying reverse iontophoresis in conjunction with high electroporation.Keywords: electroporation, reverse iontophoresis, nanochannels, noninvasive, urea, prostate-specific antigen, osteoponti

Hypocotyl Transcriptome Reveals Auxin Regulation of Growth-Promoting Genes through GA-Dependent and -Independent Pathways

Many processes critical to plant growth and development are regulated by the hormone auxin. Auxin responses are initiated through activation of a transcriptional response mediated by the TIR1/AFB family of F-box protein auxin receptors as well as the AUX/IAA and ARF families of transcriptional regulators. However, there is little information on how auxin regulates a specific cellular response. To begin to address this question, we have focused on auxin regulation of cell expansion in the Arabidopsis hypocotyl. We show that auxin-mediated hypocotyl elongation is dependent upon the TIR1/AFB family of auxin receptors and degradation of AUX/IAA repressors. We also use microarray studies of elongating hypocotyls to show that a number of growth-associated processes are activated by auxin including gibberellin biosynthesis, cell wall reorganization and biogenesis, and others. Our studies indicate that GA biosynthesis is required for normal response to auxin in the hypocotyl but that the overall transcriptional auxin output consists of PIF-dependent and -independent genes. We propose that auxin acts independently from and interdependently with PIF and GA pathways to regulate expression of growth-associated genes in cell expansion

Gibberellin signaling requires chromatin remodeler PICKLE to promote vegetative growth and phase transitions

© 2017 American Society of Plant Biologists. All rights reserved. PICKLE (PKL) is an ATP-dependent chromodomain-helicase-DNA-binding domain (CHD3) chromatin remodeling enzyme in Arabidopsis (Arabidopsis thaliana). Previous studies showed that PKL promotes embryonic-to-vegetative transition by inhibiting expression of seed-specific genes during seed germination. The pkl mutants display a low penetrance of the “pickle root” phenotype, with a thick and green primary root that retains embryonic characteristics. The penetrance of this pickle root phenotype in pkl is dramatically increased in gibberellin (GA)-deficient conditions. At adult stages, the pkl mutants are semidwarfs with delayed flowering time, which resemble reduced GA-signaling mutants. These findings suggest that PKL may play a positive role in regulating GA signaling. A recent biochemical analysis further showed that PKL and GA signaling repressors DELLAs antagonistically regulate hypocotyl cell elongation genes by direct protein-protein interaction. To elucidate further the role of PKL in GA signaling and plant development, we studied the genetic interaction between PKL and DELLAs using the hextuple mutant containing pkl and della pentuple (dP) mutations. Here, we show that PKL is required for most of GA-promoted developmental processes, including vegetative growth such as hypocotyl, leaf, and inflorescence stem elongation, and phase transitions such as juvenile-to-adult leaf and vegetative-to-reproductive phase. The removal of all DELLA functions (in the dP background) cannot rescue these phenotypes in pkl. RNA-sequencing analysis using the ga1 (a GA-deficient mutant), pkl, and the ga1 pkl double mutant further shows that expression of 80% of GA-responsive genes in seedlings is PKL dependent, including genes that function in cell elongation, cell division, and phase transitions. These results indicate that the CHD3 chromatin remodeler PKL is required for regulating gene expression during most of GA-regulated developmental processes

Role of the gibberellin receptors GID1 during fruit-set in Arabidopsis

[EN] Gibberellins (GAs) play a critical role in fruit-set and fruit growth. Gibberellin is perceived by its nuclear receptors GA INSENSITIVE DWARF1s (GID1s), which then trigger degradation of downstream repressors DELLAs. To understand the role of the three GA receptor genes (GID1A, GID1B and GID1C) in Arabidopsis during fruit initiation, we have examined their temporal and spatial localization, in combination with analysis of mutant phenotypes. Distinct expression patterns are revealed for each GID1: GID1A is expressed throughout the whole pistil, while GID1B is expressed in ovules, and GID1C is expressed in valves. Functional study of gid1 mutant combinations confirms that GID1A plays a major role during fruit-set and growth, whereas GID1B and GID1C have specific roles in seed development and pod elongation, respectively. Therefore, in ovules, GA perception is mediated by GID1A and GID1B, while GID1A and GID1C are involved in GA perception in valves. To identify tissue-specific interactions between GID1s and DELLAs, we analyzed spatial expression patterns of four DELLA genes that have a role in fruit initiation (GAI, RGA, RGL1 and RGL2). Our data suggest that GID1A can interact with RGA and GAI in all tissues, whereas GID1C-RGL1 and GID1B-RGL2 interactions only occur in valves and ovules, respectively. These results uncover specific functions of each GID1-DELLA in the different GA-dependent processes that occur upon fruit-set. In addition, the distribution of GA receptors in valves along with lack of expression of GA biosynthesis genes in this tissue, strongly suggests transport of GAs from the developing seeds to promote fruit growth.We wish to thank Dr Masatoshi Nakajima (University of Tokyo, Japan) for providing the pGID1:GID1-GUS lines, and Dr Peter Hedden (Rothamsted Research, UK) for the pGA20ox:GA20ox-GUS lines. We also thank Ms C. Fuster and M. A. Argomaniz for technical assistance. This work has been supported by grants BIO2008-01039 and BIO2011-26302 from the Spanish Ministry of Science and Innovation and ACOMP/2010/079 and ACOMP/2011/287 from the Generalitat Valenciana for M. A. P.-A. and USDA grants 2010-65116-20460 and 2014-67013-21548 for T. P. S. C. G.-G. received a JAE PhD fellowship from the Spanish Council for Scientific Research (CSIC).Gallego Giraldo, C.; Hu, J.; Urbez Lagunas, C.; Gómez Jiménez, MD.; Sun, TP.; Perez Amador, MA. (2014). Role of the gibberellin receptors GID1 during fruit-set in Arabidopsis. Plant Journal. 79(6):1020-1032. doi:10.1111/tpj.12603S1020103279

Self-catheterization of urinary bladder complicated with extraperitoneal abscess that mimics an infected bladder diverticulum

AbstractFor patients who are suffering from neurogenic lower urinary tract dysfunction, intermittent urinary catheterization is an efficient way to empty the bladder.1 However, the method may result in various complications. Herein we present a rare complication of extraperitoneal abscess owing to intermittent urinary catheterization in a 62-year-old male who had cervical spine injury and was treated with intermittent urethral catheterization for neurogenic lower urinary tract dysfunction. Treatment and a literature review are also described