208 research outputs found
A Single-Machine Scheduling Problem with Uncertainty in Processing Times and Outsourcing Costs
We consider a single-machine scheduling problem with an outsourcing option in an environment where the processing time and outsourcing cost are uncertain. The performance measure is the total cost of processing some jobs in-house and outsourcing the rest. The cost of processing in-house jobs is measured as the total weighted completion time, which can be considered the operating cost. The uncertainty is described through either an interval or a discrete scenario. The objective is to minimize the maximum deviation from the optimal cost of each scenario. Since the deterministic version is known to be NP-hard, we focus on two special cases, one in which all jobs have identical weights and the other in which all jobs have identical processing times. We analyze the computational complexity of each case and present the conditions that make them polynomially solvable
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Inhibition of cAMP/PKA Pathway Protects Optic Nerve Head Astrocytes against Oxidative Stress by Akt/Bax Phosphorylation-Mediated Mfn1/2 Oligomerization.
Glaucoma is characterized by a progressive optic nerve degeneration and retinal ganglion cell loss, but the underlying biological basis for the accompanying neurodegeneration is not known. Accumulating evidence indicates that structural and functional abnormalities of astrocytes within the optic nerve head (ONH) have a role in glaucomatous neurodegeneration. Here, we investigate the impact of activation of cyclic adenosine 3',5'-monophosphate (cAMP)/protein kinase A (PKA) pathway on mitochondrial dynamics of ONH astrocytes exposed to oxidative stress. ONH astrocytes showed a significant loss of astrocytic processes in the glial lamina of glaucomatous DBA/2J mice, accompanied by basement membrane thickening and collagen deposition in blood vessels and axonal degeneration. Serial block-face scanning electron microscopy data analysis demonstrated that numbers of total and branched mitochondria were significantly increased in ONH astrocytes, while mitochondrial length and volume density were significantly decreased. We found that hydrogen peroxide- (H2O2-) induced oxidative stress compromised not only mitochondrial bioenergetics by reducing the basal and maximal respiration but also balance of mitochondrial dynamics by decreasing dynamin-related protein 1 (Drp1) protein expression in rat ONH astrocytes. In contrast, elevated cAMP by dibutyryl-cAMP (dbcAMP) or isobutylmethylxanthine treatment significantly increased Drp1 protein expression in ONH astrocytes. Elevated cAMP exacerbated the impairment of mitochondrial dynamics and reduction of cell viability to oxidative stress in ONH astrocytes by decreasing optic atrophy type 1 (OPA1), and mitofusin (Mfn)1/2 protein expression. Following combined treatment with H2O2 and dbcAMP, PKA inhibition restored mitochondrial dynamics by increasing mitochondrial length and decreasing mitochondrial number, and this promoted cell viability in ONH astrocytes. Also, PKA inhibition significantly promoted Akt/Bax phosphorylation and Mfn1/2 oligomerization in ONH astrocytes. These results suggest that modulation of the cAMP/PKA signaling pathway may have therapeutic potential by activating Akt/Bax phosphorylation and promoting Mfn1/2 oligomerization in glaucomatous ONH astrocytes
Elevated intracellular cAMP exacerbates vulnerability to oxidative stress in optic nerve head astrocytes.
Glaucoma is characterized by a progressive loss of retinal ganglion cells and their axons, but the underlying biological basis for the accompanying neurodegeneration is not known. Accumulating evidence indicates that structural and functional abnormalities of astrocytes within the optic nerve head (ONH) have a role. However, whether the activation of cyclic adenosine 3',5'-monophosphate (cAMP) signaling pathway is associated with astrocyte dysfunction in the ONH remains unknown. We report here that the cAMP/protein kinase A (PKA) pathway is critical to ONH astrocyte dysfunction, leading to caspase-3 activation and cell death via the AKT/Bim/Bax signaling pathway. Furthermore, elevated intracellular cAMP exacerbates vulnerability to oxidative stress in ONH astrocytes, and this may contribute to axonal damage in glaucomatous neurodegeneration. Inhibition of intracellular cAMP/PKA signaling activation protects ONH astrocytes by increasing AKT phosphorylation against oxidative stress. These results strongly indicate that activation of cAMP/PKA pathway has an important role in astrocyte dysfunction, and suggest that modulating cAMP/PKA pathway has therapeutic potential for glaucomatous ONH degeneration
Efficient hybrid organic-inorganic light emitting diodes with self-assembled dipole molecule deposited metal oxides
We investigate the effect of self-assembled dipole molecules (SADMs) on ZnO surface in hybrid organic-inorganic polymeric light-emitting diodes (HyPLEDs). Despite the SADM being extremely thin, the magnitude and orientation of SADM dipole moment effectively influenced the work function of the ZnO. As a consequence, the charge injection barrier between the conduction band of the ZnO and the lowest unoccupied molecular orbital of poly(9,9(')-dioctylfluorene)-co-benzothiadiazole could be efficiently controlled resulting that electron injection efficiency is remarkably enhanced. The HyPLEDs modified with a negative dipolar SADM exhibited enhanced device performances, which correspond to approximately a fourfold compared to those of unmodified HyPLEDs.open442
Atypical iliac vein compression in patients with symptomatic May–Thurner syndrome
PURPOSEWe aimed to investigate the incidence, etiology, treatment, and clinical course of atypical iliac vein compressions (AIVCs) among patients with May–Thurner syndrome (MTS).METHODSA total of 173 patients who presented with MTS were retrospectively analyzed at a single center. Computed tomographic venography (CTV) was used to diagnose MTS. An AIVC was defined as the compression of the left common iliac vein (LCIV) by structures other than the right common iliac artery (RCIA) or the compression of other venous structures in the pelvic cavity instead of the LCIV. The patients with AIVC were categorized into the LCIV compression group (category A) and non-LCIV compression group (category B).RESULTSTen patients with AIVC were identified (5.8%; male/female, 5/5), five in category A and five in category B. The median age of patients was 76 years (range, 51–94 years), and the median follow-up duration was 388 days (range, 12–4694 days). In category A, the LCIVs were compressed by the left common iliac artery (LCIA) (n=2), uterine leiomyoma (n=1), LCIA aneurysm (n=1), and RCIA aneurysm (n=1). In category B, the right common iliac veins were compressed by the RCIA (n=4) and L5 osteophyte (n=1). Endovascular treatment, including balloon angioplasty and stent placement, was performed in six patients, three from each group. Three patients underwent conservative treatment due to their advanced age and comorbidities. Endovascular aneurysm repair was performed in one patient with RCIA aneurysm. Follow-up images were available for six patients, and all of them had patent venous flow.CONCLUSIONThe AIVC had an incidence of 5.8% (10/173) among symptomatic MTS patients and wide spectrum of etiologies. Pathogenesis-tailored endovascular treatments are safe and effective
Photo-patternable and transparent films using cellulose nanofibers for stretchable origami electronics
Substantial progress in flexible or stretchable electronics over the past decade has extensively impacted various technologies such as wearable devices, displays and automotive electronics for smart cars. An important challenge is the reliability of these deformable devices under thermal stress. Different coefficients of thermal expansion (CTE) between plastic substrates and the device components, which include multiple inorganic layers of metals or ceramics, induce thermal stress in the devices during fabrication processes or long-term operations with repetitions of thermal cyclic loading-unloading, leading to device failure and reliability degradation. Here, we report an unconventional approach to form photo-patternable, transparent cellulose nanofiber (CNF) hybrid films as flexible and stretchable substrates to improve device reliability using simultaneous electrospinning and spraying. The electrospun polymeric backbones and sprayed CNF fillers enable the resulting hybrid structure to be photolithographically patternable as a negative photoresist and thermally and mechanically stable, presenting outstanding optical transparency and low CTE. We also formed stretchable origami substrates using the CNF hybrid that are composed of rigid support fixtures and elastomeric joints, exploiting the photo-patternability. A demonstration of transparent organic light-emitting diodes and touchscreen panels on the hybrid film suggests its potential for use in next-generation electronics.ope
Regulation of stomatal development by stomatal lineage miRNAs
Stomata in the plant epidermis play a critical role in growth and survival by controlling gas exchange, transpiration, and immunity to pathogens. Plants modulate stomatal cell fate and patterning through key transcriptional factors and signaling pathways. MicroRNAs (miRNAs) are known to contribute to developmental plasticity in multicellular organisms; however, no miRNAs appear to target the known regulators of stomatal development. It remains unclear as to whether miRNAs are involved in stomatal development. Here, we report highly dynamic, developmentally stage-specific miRNA expression profiles from stomatal lineage cells. We demonstrate that stomatal lineage miRNAs positively and negatively regulate stomatal formation and patterning to avoid clustered stomata. Target prediction of stomatal lineage miRNAs implicates potential cellular processes in stomatal development. We show that miR399-mediated PHO2 regulation, involved in phosphate homeostasis, contributes to the control of stomatal development. Our study demonstrates that miRNAs constitute a critical component in the regulatory mechanisms controlling stomatal development. © 2020 National Academy of Sciences. All rights reserved.1
High performance polymer light-emitting diodes with N-type metal oxide/conjugated polyelectrolyte hybrid charge transport layers
We present an interfacial engineering strategy employing n-type-metal-oxide/conjugated-polyelectrolyte (CPE) hybrid charge-transport layers for highly efficient polymer light-emitting diodes (PLEDs). The hybrid metal-oxide/CPE layer facilitates electron-injection, while blocking hole-transport, and thereby maximizes electron-hole recombination within the emitting layer. A series of metal-oxide/CPE combinations were tested in inverted PLEDs (FTO/metal-oxide/CPF8BT/MoO3/Au). Specifically, HfO2/CPE double layer achieved an electroluminescence (EL) efficiency of up to 25.8 cd/A (@ 6.4 V, one of the highest values reported for fluorescent PLEDs).open11
Epidemiological and Clinical Parameters Features of Patients with Clonorchiasis in the Geum River Basin, Republic of Korea
This study was conducted to evaluate the infection rates of Clonorchis sinensis and laboratory findings in infected people. The 3,167 fecal samples, from nine villages in Okcheon-gun, were examined
Renal Toxicity Evaluation and Comparison Between Visipaque (Iodixanol) and Hexabrix (Ioxaglate) in Patients With Renal Insufficiency Undergoing Coronary Angiography The RECOVER Study: A Randomized Controlled Trial
ObjectivesThis study sought to compare the nephrotoxicity of iodixanol and ioxaglate in patients with renal impairment undergoing coronary angiography.BackgroundIodixanol, a nonionic, dimeric, iso-osmolar contrast medium (IOCM), may be less nephrotoxic than low-osmolar contrast media (LOCM) in high-risk patients.MethodsIn a prospective, randomized trial in 300 adults with creatinine clearance (CrCl) ≤60 ml/min, patients received either iodixanol or ioxaglate and underwent coronary angiography with or without percutaneous coronary intervention. The primary end point was the incidence of contrast-induced nephropathy (CIN) (an increase in serum creatinine [SCr] ≥25% or ≥0.5 mg/dl [≥44.2 μmol/l]). The incidence of CIN in patients with severe renal impairment at baseline (CrCl <30 ml/min) or diabetes and in those receiving large doses (≥140 ml) of contrast medium was also determined.ResultsThe incidence of CIN was significantly lower with iodixanol (7.9%) than with ioxaglate (17.0%; p = 0.021), corresponding to an odds ratio (OR) of CIN of 0.415 (95% confidence interval [CI] 0.194 to 0.889) for iodixanol. The incidence of CIN was also significantly lower with iodixanol in patients with severe renal impairment (p = 0.023) or concomitant diabetes (p = 0.041), or in patients given ≥140 ml of contrast media (p = 0.038). Multivariate analysis identified use of ioxaglate (OR 2.65, 95% CI 1.11 to 6.33, p = 0.028), baseline SCr, mg/dl (OR 2.0, 95% CI 1.04 to 3.85, p = 0.038), and left ventricular ejection fraction, % (OR 0.97, 95% CI 0.94 to 0.99, p = 0.019) as independent risk factors for CIN.ConclusionsThe IOCM iodixanol was significantly less nephrotoxic than ioxaglate, an ionic, dimeric LOCM. (The RECOVER Trial; http://clinicaltrials.gov; NCT00247325
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