The effects of varying sulfate concentrations with pH on continuous fermentative hydrogen production were studied using anaerobic mixed cultures growing on a glucose substrate in a chemostat reactor. ...The maximum hydrogen production rate was 2.8 L/day at pH 5.5 and sulfate concentration of 3000 mg/L. Hydrogen production and residual sulfate level decreased with increasing the pH from 5.5 to 6.2. The volatile fatty acids (VFAs) and ethanol fractions in the effluent were in the order of butyric acid (HBu) > acetic acid (HAc) > ethanol > propionic acid (HPr). Fluorescence In Situ Hybridization (FISH) analysis revealed the presence of hydrogen producing bacteria (HPB) under all pH ranges while sulfate reducing bacteria (SRB) were present at pH 5.8 and 6.2. The inhibition in hydrogen production by SRB at pH 6.2 diminished entirely by lowering to pH 5.5, at which activity of SRB is substantially suppressed.
Semiconducting lead halide perovskite nanocrystals (PNCs) are regarded as promising candidates for next‐generation optoelectronic devices due to their solution processability and outstanding ...optoelectronic properties. While the field of light‐emitting diodes (LEDs) and photovoltaics (PVs), two prime examples of optoelectronic devices, has recently seen a multitude of efforts toward high‐performance PNC‐based devices, realizing both devices with high efficiencies and stabilities through a single PNC processing strategy has remained a challenge. In this work, diphenylpropylammonium (DPAI) surface ligands, found through a judicious ab‐initio‐based ligand search, are shown to provide a solution to this problem. The universal PNC ink with DPAI ligands presented here, prepared through a solution‐phase ligand‐exchange process, simultaneously allows single‐step processed LED and PV devices with peak electroluminescence external quantum efficiency of 17.00% and power conversion efficiency of 14.92% (stabilized output 14.00%), respectively. It is revealed that a careful design of the aromatic rings such as in DPAI is the decisive factor in bestowing such high performances, ease of solution processing, and improved phase stability up to 120 days. This work illustrates the power of ligand design in producing PNC ink formulations for high‐throughput production of optoelectronic devices; it also paves a path for “dual‐mode” devices with both PV and LED functionalities.
A functional CsPbI3 perovskite nanocrystal ink is developed through solution‐phase ligand exchange with 3,3‐diphenylpropylammonium iodide, attributed to singular stabilization by diphenyl group and rigorous surface passivation. This enables a “universal” demonstration of high‐performance photovoltaics and light‐emitting devices while ensuring excellent phase stability and device longevity.
Three new triterpenoid saponins, platyconic acid B lactone (1), deapio-platyconic acid B lactone (2), and deapio-platycodin D2 (3), together with 17 known triterpenoid saponins, were isolated from a ...root extract of Platycodon grandiflorum. The structures of 1−3 were determined on the basis of spectroscopic data interpretation and chemical transformation. Saponins with a platycodigenin or polygalacic acid unit as a sapogenin demonstrated significant inhibitory effects on the proliferation of a small panel of cultured human tumor cells.
Immunization using a microneedle patch coated with vaccine offers the promise of simplified vaccination logistics and increased vaccine immunogenicity. This study examined the stability of influenza ...vaccine during the microneedle coating process, with a focus on the role of coating formulation excipients. Thick, uniform coatings were obtained using coating formulations containing a viscosity enhancer and surfactant, but these formulations retained little functional vaccine hemagglutinin (HA) activity after coating. Vaccine coating in a trehalose-only formulation retained about 40–50% of vaccine activity, which is a significant improvement. The partial viral activity loss observed in the trehalose-only formulation was hypothesized to come from osmotic pressure-induced vaccine destabilization. We found that inclusion of a viscosity enhancer, carboxymethyl cellulose, overcame this effect and retained full vaccine activity on both washed and plasma-cleaned titanium surfaces. The addition of polymeric surfactant, Lutrol® micro 68, to the trehalose formulation generated phase transformations of the vaccine coating, such as crystallization and phase separation, which was correlated to additional vaccine activity loss, especially when coating on hydrophilic, plasma-cleaned titanium. Again, the addition of a viscosity enhancer suppressed the surfactant-induced phase transformations during drying, which was confirmed by in vivo assessment of antibody response and survival rate after immunization in mice. We conclude that trehalose and a viscosity enhancer are beneficial coating excipients, but the inclusion of surfactant is detrimental to vaccine stability.
Display omitted
When the intensity of the incident light increases, the photocurrents of organic photodiodes (OPDs) exhibit relatively early saturation, due to which OPDs cannot easily detect objects against strong ...backlights, such as sunlight. In this study, this problem is addressed by introducing a light‐intensity‐dependent transition of the operation mode, such that the operation mode of the OPD autonomously changes to overcome early photocurrent saturation as the incident light intensity passes the threshold intensity. The photoactive layer is doped with a strategically designed and synthesized molecular switch, 1,2‐bis‐(2‐methyl‐5‐(4‐cyanobiphenyl)‐3‐thienyl)tetrafluorobenzene (DAB). The proposed OPD exhibits a typical OPD performance with an external quantum efficiency (EQE) of <100% and a photomultiplication behavior with an EQE of >100% under low‐intensity and high‐intensity light illuminations, respectively, thereby resulting in an extension of the photoresponse linearity to a light intensity of 434 mW cm−2. This unique and reversible transition of the operation mode can be explained by the unbalanced quantum yield of photocyclization/photocycloreversion of the molecular switch. The details of the operation mechanism are discussed in conjunction with various photophysical analyses. Furthermore, they establish a prototype image sensor with an array of molecular‐switch‐embedded OPD pixels to demonstrate their extremely high sensitivity against strong light illumination.
A molecular‐switch‐embedded organic photodiode exhibits an autonomous transition of the operation mode between photovoltaic‐ and photomultiplication‐type photodiodes, resulting in the extension of the photoresponse linearity to 434 W cm−2. This mechanism is enabled by the light‐intensity‐adjusted cyclization–cycloreversion equilibrium of diarylethene‐based molecular switches. Consequently, prototype image sensors with reliable sensitivity against strong backlight are demonstrated.
Prins reaction of homoallenyl alcohols with aldehyde dimethylacetals in the presence of methoxyacetic acid directly affords tetrasubstituted pyrans relevant to halichondrins with complete control of ...the C27 stereogenic center. Regioselective Tsuji reduction of the resultant allylic acetates stereoselectively establishes the C25 stereogenic center and C26 exocyclic olefin. Building upon these findings, we achieved concise access to the halichondrin C14–C38 and eribulin C14–C35 fragments.
Skeletal Muscle–Specific Deletion of Lipoprotein Lipase Enhances Insulin Signaling in Skeletal Muscle but Causes Insulin Resistance
in Liver and Other Tissues
Hong Wang 1 ,
Leslie A. Knaub 1 ,
Dalan ...R. Jensen 1 ,
Dae Young Jung 2 ,
Eun-Gyoung Hong 2 ,
Hwi-Jin Ko 2 ,
Alison M. Coates 1 ,
Ira J. Goldberg 3 ,
Becky A. de la Houssaye 4 ,
Rachel C. Janssen 4 ,
Carrie E. McCurdy 4 ,
Shaikh M. Rahman 4 ,
Cheol Soo Choi 5 ,
Gerald I. Shulman 6 ,
Jason K. Kim 2 ,
Jacob E. Friedman 4 and
Robert H. Eckel 1
1 Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
2 Department of Cellular & Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
3 Department of Medicine, Columbia University, New York City, New York
4 Department of Pediatrics, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
5 Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
6 Department of Internal Medicine, Department of Cellular & Molecular Physiology, Howard Hughes Medical Institute, Yale University
School of Medicine, New Haven, Connecticut
Corresponding author: Robert H. Eckel, robert.eckel{at}uchsc.edu
Abstract
OBJECTIVE— Skeletal muscle–specific LPL knockout mouse (SMLPL −/− ) were created to study the systemic impact of reduced lipoprotein lipid delivery in skeletal muscle on insulin sensitivity,
body weight, and composition.
RESEARCH DESIGN AND METHODS— Tissue-specific insulin sensitivity was assessed using a hyperinsulinemic-euglycemic clamp and 2-deoxyglucose uptake. Gene
expression and insulin-signaling molecules were compared in skeletal muscle and liver of SMLPL −/− and control mice.
RESULTS— Nine-week-old SMLPL −/− mice showed no differences in body weight, fat mass, or whole-body insulin sensitivity, but older SMLPL −/− mice had greater weight gain and whole-body insulin resistance. High-fat diet feeding accelerated the development of obesity.
In young SMLPL −/− mice, insulin-stimulated glucose uptake was increased 58% in the skeletal muscle, but was reduced in white adipose tissue
(WAT) and heart. Insulin action was also diminished in liver: 40% suppression of hepatic glucose production in SMLPL −/− vs. 90% in control mice. Skeletal muscle triglyceride was 38% lower, and insulin-stimulated phosphorylated Akt (Ser473) was
twofold greater in SMLPL −/− mice without changes in IRS-1 tyrosine phosphorylation and phosphatidylinositol 3-kinase activity. Hepatic triglyceride and
liver X receptor, carbohydrate response element–binding protein, and PEPCK mRNAs were unaffected in SMLPL −/− mice, but peroxisome proliferator–activated receptor (PPAR)-γ coactivator-1α and interleukin-1β mRNAs were higher, and stearoyl–coenzyme
A desaturase-1 and PPARγ mRNAs were reduced.
CONCLUSIONS— LPL deletion in skeletal muscle reduces lipid storage and increases insulin signaling in skeletal muscle without changes in
body composition. Moreover, lack of LPL in skeletal muscle results in insulin resistance in other key metabolic tissues and
ultimately leads to obesity and systemic insulin resistance.
Footnotes
Published ahead of print at http://diabetes.diabetesjournals.org on 24 October 2008.
Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work
is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore
be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
See accompanying commentary, p. 16 .
Accepted October 8, 2008.
Received December 29, 2007.
DIABETES
PDF
