172 research outputs found
Kajian Perbandingan Pelarut : Distilat Asam Lemak Minyak Sawit (DALMS) dan Penggunaan Pelarut Daur Ulang Pada Proses Saponifikasi DALMS Untuk Memperoleh Rendemen Tertinggi
Distilat Asam Lemak Minyak Sawit (DALMS) merupakan produk samping
pemurnian fisik minyak sawit mentah yang terdiri dari asam lemak bebas, gliserida,
serta bioaktif multikomponen seperti skualen, karoten, tokoferol dan tokotrienol,
serta fitosterol. Bioaktif multikomponen dapat diperoleh dengan saponifikasi
DALMS dan ekstraksi fraksi tidak tersabunkan (FTT). Pelarut yang digunakan
pada saponifikasi dan ekstraksi FTT DALMS yaitu kombinasi etanol, heksana, dan
akuades. Pelarut saponifikasi menggunakan etanol, sedangkan ekstraksi
menggunakan heksana dan akuades. Tujuan penelitian adalah menentukan
kondisi optimum proses saponifikasi dengan parameter variasi perbandingan
pelarut : DALMS (Tahap 1) serta penggunaan pelarut baru dan pelarut daur ulang
(Tahap 2) dengan respon rendemen FTT. Rendemen tertinggi akan dilakukan
analisa bioaktif meliputi Vitamin E (α-tokoferol, α-tokotrienol, δ-tokotrienol, γ-
tokotrienol), fitosterol (kampesterol, β-sitosterol, stigmasterol), karotenoid (α–
karoten dan β–karoten) serta skualen.
Penelitian terdiri dari penelitian pendahuluan dan dua tahap penelitian
utama. Penelitian pendahuluan dilakukan untuk menentukan interval atas dan
bawah perbandingan etanol : DALMS (v/b), heksana : DALMS (v/b) dan akuades
: DALMS (v/b) dengan respon rendemen. Hasil penelitian pendahuluan masingmasing pada perlakuan etanol 6:1 (v/b), perlakuan heksana perbandingan 8:1
(v/b), dan perlakuan akuades 12:1 (v/b) menghasilkan rendemen tertinggi, masingmasing (0,51%; 0,67%; 0,21%). Berdasarkan data tersebut, batas bawah dari
masing-masing perbandingan pelarut yaitu etanol : DALMS 5:1 (v/b), heksana :
DALMS 6:1 (v/b), dan akuades : DALMS 10: 1 (v/b). Batas atas untuk masingmasing pelarut : DALMS yaitu etanol : DALMS 7:1 (v/b), heksana : DALMS 10:1
(v/b), dan akuades : DALMS 14:1 (v/b). Batas bawah dan batas atas yang
diperoleh kemudian digunakan pada penelitian tahap 1.
Penelitian tahap 1 bertujuan untuk menentukan titik optimum pelarut :
DALMS pada saponifikasi dan ekstraksi menggunakan Rancangan Komposit
Pusat Metode Permukaan Respon yang terdiri dari tiga variabel yaitu
perbandingan etanol : DALMS (v/b) (X1), heksana : DALMS (v/b) (X2) dan akuades
: DALMS (v/b) (X3) dengan respon rendemen. Perlakuan terbaik dilakukan analisa
bilangan oksidasi (bilangan peroksida dan p-anisidin) dan senyawa bioaktif
meliputi Vitamin E (α-tokoferol, α-tokotrienol, δ-tokotrienol, γ-tokotrienol), fitosterol
(kampesterol, β-sitosterol, stigmasterol), karotenoid (α–karoten dan β–karoten)
dan skualen. Hasil penelitian menunjukkan penggunaan etanol : DALMS (6,5 : 1)
(v/b), heksana : DALMS (9,7 : 1) (v/b), dan akuades (12,6 : 1) (v/b) merupakan
kombinasi pelarut terbaik dengan rerata rendemen 2,23 + 0,11%. Optimasi
saponifikasi dan ekstraksi berpengaruh terhadap kadar bioaktif rendemen FTT
DALMS. Senyawa β-sitosterol, skualen, dan total Vitamin E yang terdiri dari α-
tokoferol, α-tokotrienol, δ-tokotrienol, γ-tokotrienol memiliki nilai lebih tinggi saat
dilakukan optimasi pelarut dibandingkan sebelum optimasi. Perlakuan optimasi
memiliki senyawa stigmasterol dan kampesterol lebih rendah dibandingkan perlakuan sebelum optimasi. Senyawa α–karoten dan β–karoten tidak dapat
terekstrak pada perlakuan setelah optimasi maupun sebelum optimasi. Optimasi
pelarut memiliki bilangan peroksida yang lebih tinggi dari perlakuan sebelum
optimasi, serta bilangan p-Anisidin yang lebih rendah dibandingkan perlakuan
sebelum optimasi.
Penelitian tahap 2 bertujuan untuk mengetahui apakah terdapat perbedaan
nyata penggunaan pelarut baru, pelarut daur ulang, dan kombinasi keduanya pada
saponifikasi dan ekstraksi DALMS menggunakan Rancangan Acak Lengkap
(RAL). Respon pada tahap ini yaitu rendemen. Data yang diperoleh dianalisa
menggunakan One Way Analysis of Variance (ANOVA) pada α = 0,05. Perlakuan
dengan rendemen tertinggi dilakukan uji bilangan oksidasi (bilangan peroksida dan
p-anisidin) dan senyawa bioaktif (meliputi Vitamin E (α-tokoferol, α-tokotrienol, δ-
tokotrienol, γ-tokotrienol), fitosterol (kampesterol, β-sitosterol, stigmasterol),
karotenoid (α–karoten dan β–karoten) dan skualen. Penggunaan pelarut daur
ulang memiliki nilai rendemen tidak berbeda nyata dibandingkan dengan
penggunaan pelarut baru maupun kombinasi pelarut baru : pelarut daur ulang,
sehingga FTT yang dihasilkan dari saponifikasi dan ekstraksi menggunakan
pelarut daur ulang dilakukan karakterisasi bilangan oksidasi dan senyawa bioaktif.
Bilangan oksidasi pada penggunaan pelarut daur ulang memiliki nilai yang lebih
tinggi diabndingkan penggunaan pelarut baru, yang ditandai dengan bilangan
peroksida dan anisidin yang memiliki nilai lebih tinggi dari penggunaan pelarut
baru. Penggunaan pelarut daur ulang memiliki kadar β-sitosterol, kampesterol, dan
skualen lebih tinggi dibandingkan pelarut baru. Akan tetapi, penggunaan pelarut
daur ulang menghasilkan kadar stigmasterol dan Vitamin E yang terdiri dari α-
tokoferol, α-tokotrienol, δ-tokotrienol, serta γ-tokotrienol lebih rendah dibandingkan
pelarut baru. Senyawa α–karoten dan β–karoten tidak terdeteksi pada saponifikasi
dan ekstraksi menggunakan pelarut daur ulan
Metodologías y técnicas instrumentales para el estudio de sistemas de aguas ácidas
Los sistemas de aguas ácidas presentan una gran complejidad geoquímica, ya que involucran una gran variedad de procesos de interacción entre aguas superficiales o subterráneas, gases (sobre todo el oxígeno atmosférico), minerales responsables de la generación de acidez y aquellos que intervienen en la atenuación natural de los contenidos de elementos disueltos y distintos tipos de actividad biológica. Por ello la calidad y fiabilidad de un estudio geoquímico en este tipo de sistemas dependen en gran medida de que las técnicas de muestreo, preservación y análisis de aguas, minerales, gases y muestras biológicas sean las más adecuadas para el tipo de interpretaciones que se desea realizar. En este trabajo se detallan las principales características de los métodos y técnicas más habituales empleados en los estudios geoquímicos desarrollados en sistemas de aguas ácidas en entornos ricos en sulfuros, teniendo en cuenta no sólo los distintos tipos de muestras habituales sino también las peculiaridades de los distintos tipos de sistemas (cortas mineras, balsas de lodos, arroyos ácidos, etc). Además, se indican las posibles aplicaciones y dificultades de cada metodología y técnica descrita y se proporcionan referencias a otros estudios científico-técnicos que permiten profundizar en los fundamentos de su us
The syndrome of central hypothyroidism and macroorchidism: IGSF1 controls TRHR and FSHB expression by differential modulation of pituitary TGFβ and Activin pathways
IGSF1 (Immunoglobulin Superfamily 1) gene defects cause central hypothyroidism and macroorchidism. However, the pathogenic mechanisms of the disease remain unclear. Based on a patient with a full deletion of IGSF1 clinically followed from neonate to adulthood, we investigated a common pituitary origin for hypothyroidism and macroorchidism, and the role of IGSF1 as regulator of pituitary hormone secretion. The patient showed congenital central hypothyroidism with reduced TSH biopotency, over-secretion of FSH at neonatal minipuberty and macroorchidism from 3 years of age. His markedly elevated inhibin B was unable to inhibit FSH secretion, indicating a status of pituitary inhibin B resistance. We show here that IGSF1 is expressed both in thyrotropes and gonadotropes of the pituitary and in Leydig and germ cells in the testes, but at very low levels in Sertoli cells. Furthermore, IGSF1 stimulates transcription of the thyrotropin-releasing hormone receptor (TRHR) by negative modulation of the TGFβ1-Smad signaling pathway, and enhances the synthesis and biopotency of TSH, the hormone secreted by thyrotropes. By contrast, IGSF1 strongly down-regulates the activin-Smad pathway, leading to reduced expression of FSHB, the hormone secreted by gonadotropes. In conclusion, two relevant molecular mechanisms linked to central hypothyroidism and macroorchidism in IGSF1 deficiency are identified, revealing IGSF1 as an important regulator of TGFβ/Activin pathways in the pituitary
A First Search for coincident Gravitational Waves and High Energy Neutrinos using LIGO, Virgo and ANTARES data from 2007
We present the results of the first search for gravitational wave bursts
associated with high energy neutrinos. Together, these messengers could reveal
new, hidden sources that are not observed by conventional photon astronomy,
particularly at high energy. Our search uses neutrinos detected by the
underwater neutrino telescope ANTARES in its 5 line configuration during the
period January - September 2007, which coincided with the fifth and first
science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed
for candidate gravitational-wave signals coincident in time and direction with
the neutrino events. No significant coincident events were observed. We place
limits on the density of joint high energy neutrino - gravitational wave
emission events in the local universe, and compare them with densities of
merger and core-collapse events.Comment: 19 pages, 8 figures, science summary page at
http://www.ligo.org/science/Publication-S5LV_ANTARES/index.php. Public access
area to figures, tables at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p120000
Permanent Genetic Resources added to Molecular Ecology Resources Database 1 February 2013-31 March 2013
This article documents the addition of 142 microsatellite marker loci to the Molecular Ecology Resources database. Loci were developed for the following species: Agriophyllum squarrosum, Amazilia cyanocephala, Batillaria attramentaria, Fungal strain CTeY1 (Ascomycota), Gadopsis marmoratus, Juniperus phoenicea subsp. turbinata, Liriomyza sativae, Lupinus polyphyllus, Metschnikowia reukaufii, Puccinia striiformis and Xylocopa grisescens. These loci were cross-tested on the following species: Amazilia beryllina, Amazilia candida, Amazilia rutila, Amazilia tzacatl, Amazilia violiceps, Amazilia yucatanensis, Campylopterus curvipennis, Cynanthus sordidus, Hylocharis leucotis, Juniperus brevifolia, Juniperus cedrus, Juniperus osteosperma, Juniperus oxycedrus, Juniperus thurifera, Liriomyza bryoniae, Liriomyza chinensis, Liriomyza huidobrensis and Liriomyza trifolii. © 2013 John Wiley & Sons Ltd.Peer Reviewe
Broadband Quantum Enhancement of the LIGO Detectors with Frequency-Dependent Squeezing
Quantum noise imposes a fundamental limitation on the sensitivity of interferometric gravitational-wave detectors like LIGO, manifesting as shot noise and quantum radiation pressure noise. Here, we present the first realization of frequency-dependent squeezing in full-scale gravitational-wave detectors, resulting in the reduction of both shot noise and quantum radiation pressure noise, with broadband detector enhancement from tens of hertz to several kilohertz. In the LIGO Hanford detector, squeezing reduced the detector noise amplitude by a factor of 1.6 (4.0 dB) near 1 kHz; in the Livingston detector, the noise reduction was a factor of 1.9 (5.8 dB). These improvements directly impact LIGO's scientific output for high-frequency sources (e.g., binary neutron star postmerger physics). The improved low-frequency sensitivity, which boosted the detector range by 15%-18% with respect to no squeezing, corresponds to an increase in the astrophysical detection rate of up to 65%. Frequency-dependent squeezing was enabled by the addition of a 300-meter-long filter cavity to each detector as part of the LIGO A+ upgrade
National identity predicts public health support during a global pandemic
Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g., spatial distancing and stricter hygiene) and endorsed public policy interventions (e.g., closing bars and restaurants) during the early stage of the COVID-19 pandemic (April-May 2020). Respondents who reported identifying more strongly with their nation consistently reported greater engagement in public health behaviours and support for public health policies. Results were similar for representative and non-representative national samples. Study 2 (N = 42 countries) conceptually replicated the central finding using aggregate indices of national identity (obtained using the World Values Survey) and a measure of actual behaviour change during the pandemic (obtained from Google mobility reports). Higher levels of national identification prior to the pandemic predicted lower mobility during the early stage of the pandemic (r = −0.40). We discuss the potential implications of links between national identity, leadership, and public health for managing COVID-19 and future pandemics.publishedVersio
All-sky search for long-duration gravitational wave transients with initial LIGO
We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society
All-sky search for long-duration gravitational wave transients with initial LIGO
We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society
Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model
We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society
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