443 research outputs found

    Pengaruh Komposisi Media Tanam Dan Konsentrasi Paklobutrazol Terhadap Keragaan Tanaman Cabai (Capsicum Annuum L.) CV “Candlelight” Pada Budidaya Tanaman Secara Hidroponik

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    Capsicum annuumL. CV. “Candlelight” atau sering disebut cabai rawit tumpuk memiliki buah beraturan seperti kumpulan lilin yang menyala, cocok untuk ditanam di pot. Tanaman cabai Candlelight memiliki potensi menjadi tanaman hias, dengan membuat tinggi tanaman lebih pendek, daun lebih hijau, cabang dan jumlah daun lebih banyak melalui pemberian paklobutrazol dan penggunaan media tanam yang tepat melalui budidaya tanaman secara hidroponik. Penelitian ini bertujuan untuk mengetahui pengaruh komposisi media tanam, konsentrasi paklobutrazol dan interaksi keduanya terhadap keragaan tanaman cabai Candlelight pada budidaya tanaman secara hidroponik. Penelitian dilaksanakan pada bulan Desember 2015 sampai Juni 2016 di Rumah Kaca Universitas Lampug dengan Rancangan Acak Kelompok. Perlakuan disusun faktorial 2 x 5 dengan 3 kelompok yang terdapat 2 sub sampel. Faktor pertama adalah komposisi media tanam (M) terdiri dari; sekam bakar (m 1 ), dan sekam bakar + sekam mentah 1:1 (m 2 ). Faktor kedua konsentrasi paklobutrazol (D) terdiri; dari 0 ppm (d 0 ), 25 ppm (d 1 ), 50 ppm (d 2 ), 75 ppm (d 3 ), dan 100 ppm (d 4 ). Homogenitas ragamn diuji dengan Uji Bartlett dan aditivitas dengan Uji Tukey. Pemisahan nilai tengah diuji dengan Uji Polinomial Ortogonal pada taraf 5%. Hasil penelitian menunjukan media sekam bakar hasil lebih baik dibandingkan sekam campuran. Konsentrasi paklobutrazol 50 ppm berpengaruh terhadap jumlah daun total, tinggi tanaman, jumlah tunas, muncul bunga pertama, jumlah bunga, jumlah cabang, jumlah buah, umur buah di tanaman, panjang buah, dan kehijauan daun. Jumlah buah pada media sekam bakar tidak ada pengaruh paklobutrazol tetapi pada media campuran pengaruh konsentrasi paklobutrazol memberikan pengaruh. Pada media sekam bakar setiap penambahan konsentrasi 1 ppm paklobutrazol menurunkan tinggi tanaman sebesar 0,2 cm, sedangkan pada media sekam campuran paklobutrazol menurunkan tinggi tanaman sebesar 0,36 cm

    Direct Visualization of Laser-Driven Electron Multiple Scattering and Tunneling Distance in Strong-Field Ionization

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    Using a simple model of strong-field ionization of atoms that generalizes the well-known 3-step model from 1D to 3D, we show that the experimental photoelectron angular distributions resulting from laser ionization of xenon and argon display prominent structures that correspond to electrons that pass by their parent ion more than once before strongly scattering. The shape of these structures can be associated with the specific number of times the electron is driven past its parent ion in the laser field before scattering. Furthermore, a careful analysis of the cutoff energy of the structures allows us to experimentally measure the distance between the electron and ion at the moment of tunnel ionization. This work provides new physical insight into how atoms ionize in strong laser fields and has implications for further efforts to extract atomic and molecular dynamics from strong-field physics

    Bright, Coherent, Ultrafast Soft X-Ray Harmonics Spanning the Water Window from a Tabletop Light Source

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    We demonstrate fully phase matched high-order harmonic generation with emission spanning the water window spectral region important for bio- and nano-imaging and a breadth of materials and molecular dynamics studies. We also generate the broadest bright coherent bandwidth (~300eV) to date obtained from any light source, small or large. The harmonic photon flux at 0.5 keV is 10^3 higher than demonstrated previously, making it possible for the first time to demonstrate spatial coherence in the water window. The continuum emission is consistent with a single attosecond burst, that extends bright attosecond pulses into the soft x-ray region.Comment: 4 figures, 18 pages. Submitted for publicatio

    Characterizing Mode Anharmonicity and Huang–Rhys Factors Using Models of Femtosecond Coherence Spectra

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    Femtosecond laser pulses readily produce coherent quantum beats in transient–absorption spectra. These oscillatory signals often arise from molecular vibrations and therefore may contain information about the excited-state potential energy surface near the Franck–Condon region. Here, by fitting the measured spectra of two laser dyes to microscopic models of femtosecond coherence spectra (FCS) arising from molecular vibrations, we classify coherent quantum-beat signals as fundamentals or overtones and quantify their Huang–Rhys factors and anharmonicity values. We discuss the extracted Huang–Rhys factors in the context of quantum-chemical computations. This work solidifies the use of FCS for analysis of coherent quantum beats arising from molecular vibrations, which will aid studies of molecular aggregates and photosynthetic proteins

    Bright Coherent Ultrahigh Harmonics in the keV X-ray Regime from Mid-Infrared Femtosecond Lasers

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    High-harmonic generation (HHG) traditionally combines ~100 near-infrared laser photons to generate bright, phase-matched, extreme ultraviolet beams when the emission from many atoms adds constructively. Here, we show that by guiding a mid-infrared femtosecond laser in a high-pressure gas, ultrahigh harmonics can be generated, up to orders greater than 5000, that emerge as a bright supercontinuum that spans the entire electromagnetic spectrum from the ultraviolet to more than 1.6 kilo–electron volts, allowing, in principle, the generation of pulses as short as 2.5 attoseconds. The multiatmosphere gas pressures required for bright, phase-matched emission also support laser beam self-confinement, further enhancing the x-ray yield. Finally, the x-ray beam exhibits high spatial coherence, even though at high gas density the recolliding electrons responsible for HHG encounter other atoms during the emission process.The experimental work was funded by a National Security Science and Engineering Faculty Fellowship, and the NSF Center for EUV Science and Technology. A.G., A.J.-B., M.M.M., H.C.K. and A. Becker acknowledge support for theory from the U.S. Air Force Office of Scientific Research (grant no. FA9550-10-1-0561); A. Baltuška acknowledges support from Austrian Science Fund (FWF, grant no. U33-16) and the Austrian Research Promotion Agency (FFG, Project 820831 UPLIT); and C.H.-G. and L.P. acknowledge support from Junta de Castilla y León, Spanish MINECO (CSD2007-00013 and FIS2009-09522), and from Centro de Láseres Pulsados, CLPU. T.P., M.-C.C., A. Bahabad, M.M.M. and H.C.K. have filed for a patent on “Method for phase-matched generation of coherent soft and hard X-rays using IR lasers,” U.S. patent application 61171783 (2008)

    Applying Small Molecule Signal Transducer and Activator of Transcription-3 (STAT3) Protein Inhibitors as Pancreatic Cancer Therapeutics

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    Constitutively activated STAT3 protein has been found to be a key regulator of pancreatic cancer and a target for molecular therapeutic intervention. In this study, PG-S3-001, a small molecule derived from the SH-4-54 class of STAT3 inhibitors, was found to inhibit patient-derived pancreatic cancer cell proliferation in vitro and in vivo in the low micromolar range. PG-S3-001 binds the STAT3 protein potently, Kd = 324 nmol/L by surface plasmon resonance, and showed no effect in a kinome screen (>100 cancer-relevant kinases). In vitro studies demonstrated potent cell killing as well as inhibition of STAT3 activation in pancreatic cancer cells. To better model the tumor and its microenvironment, we utilized three-dimensional (3D) cultures of patient-derived pancreatic cancer cells in the absence and presence of cancer-associated fibroblasts (CAF). In this coculture model, inhibition of tumor growth is maintained following STAT3 inhibition in the presence of CAFs. Confocal microscopy was used to verify tumor cell death following treatment of 3D cocultures with PG-S3-001. The 3D model was predictive of in vivo efficacy as significant tumor growth inhibition was observed upon administration of PG-S3-001. These studies showed that the inhibition of STAT3 was able to impact the survival of tumor cells in a relevant 3D model, as well as in a xenograft model using patient-derived cells

    Functional and clinical studies reveal pathophysiological complexity of CLCN4-related neurodevelopmental condition

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    Missense and truncating variants in the X-chromosome-linked CLCN4 gene, resulting in reduced or complete loss-of-function (LOF) of the encoded chloride/proton exchanger ClC-4, were recently demonstrated to cause a neurocognitive phenotype in both males and females. Through international clinical matchmaking and interrogation of public variant databases we assembled a database of 90 rare CLCN4 missense variants in 90 families: 41 unique and 18 recurrent variants in 49 families. For 43 families, including 22 males and 33 females, we collated detailed clinical and segregation data. To confirm causality of variants and to obtain insight into disease mechanisms, we investigated the effect on electrophysiological properties of 59 of the variants in Xenopus oocytes using extended voltage and pH ranges. Detailed analyses revealed new pathophysiological mechanisms: 25% (15/59) of variants demonstrated LOF, characterized by a “shift” of the voltage-dependent activation to more positive voltages, and nine variants resulted in a toxic gain-of-function, associated with a disrupted gate allowing inward transport at negative voltages. Functional results were not always in line with in silico pathogenicity scores, highlighting the complexity of pathogenicity assessment for accurate genetic counselling. The complex neurocognitive and psychiatric manifestations of this condition, and hitherto under-recognized impacts on growth, gastrointestinal function, and motor control are discussed. Including published cases, we summarize features in 122 individuals from 67 families with CLCN4-related neurodevelopmental condition and suggest future research directions with the aim of improving the integrated care for individuals with this diagnosis
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