Final Goods Substitutability and Economic Growth

In this paper, I investigate the effect of substitutability among final goods on welfare growth under the environment that productivity growth in each industry is not independent of one another. In such an environment, less substitutability is favorable to the welfare growth rate and the steady state welfare level, contrasting to Baumol (1967) and Lucas (1988).

Examination of High-Torque Sandwich-Type Spherical Ultrasonic Motor Using with High-Power Multimode Annular Vibrating Stator

Spherical ultrasonic motors (SUSMs) that can operate with multiple degrees of freedom (MDOF) using only a single stator have high holding torque and high torque at low speed, which makes reduction gearing unnecessary. The simple structure of MDOF-SUSMs makes them useful as compact actuators, but their development is still insufficient for applications such as joints of humanoid robots and other systems that require MDOF and high torque. To increase the torque of a sandwich-type MDOF-SUSM, we have not only made the vibrating stator and spherical rotor larger but also improved the structure using three design concepts: (1) increasing the strength of all three vibration modes using multilayered piezoelectric actuators (MPAs) embedded in the stator, (2) enhancing the rigidity of the friction driving portion of the stator for transmitting more vibration force to the friction-driven rotor surface, and (3) making the support mechanism more stable. An MDOF-SUSM prototype was tested, and the maximum torques of rotation around the X(Y)-axis and Z-axis were measured as 1.48 N?m and 2.05 N?m, respectively. Moreover, the values for torque per unit weight of the stator were obtained as 0.87 N?m/kg for the X(Y)-axis and 1.20 N?m/kg for the Z-axis. These are larger than values reported for any other sandwich-type MDOF-SUSM of which we are aware. Hence, the new design concepts were shown to be effective for increasing torque. In addition, we measured the transient response and calculated the load characteristics of rotation around the rotor’s three orthogonal axes

Low-Dose Tramadol and Non-Steroidal Anti-Inflammatory Drug Combination Therapy Prevents the Transition to Chronic Low Back Pain

Study DesignRetrospective study.PurposeTo determine whether low-dose tramadol plus non-steroidal anti-inflammatory drug combination therapy could prevent the transition of acute low back pain to chronic low back pain.Overview of LiteratureInadequately treated early low back pain transitions to chronic low back pain occur in approximately 30% of affected individuals. The administration of non-steroidal anti-inflammatory drugs is effective for treatment of low back pain in the early stages. However, the treatment of low back pain that is resistant to non-steroidal anti-inflammatory drugs is challenging.MethodsPatients who presented with acute low back pain at our hospital were considered for inclusion in this study. After the diagnosis of acute low back pain, non-steroidal anti-inflammatory drug administration was started. Forty patients with a visual analog scale score of >5 for low back pain 1 month after treatment were finally enrolled. The first 20 patients were included in a non-steroidal anti-inflammatory drug group, and they continued non-steroidal anti-inflammatory drug therapy for 1 month. The next 20 patients were included in a combination group, and they received low-dose tramadol plus non-steroidal anti-inflammatory drug combination therapy for 1 month. The incidence of adverse events and the improvement in the visual analog scale score at 2 months after the start of treatment were analyzed.ResultsNo adverse events were observed in the non-steroidal anti-inflammatory drug group. In the combination group, administration was discontinued in 2 patients (10%) due to adverse events immediately following the start of tramadol administration. At 2 months, the improvement in the visual analog scale score was greater in the combination group than in the non-steroidal anti-inflammatory drug group (p<0.001).ConclusionsLow-dose tramadol plus non-steroidal anti-inflammatory drug combination therapy might decrease the incidence of adverse events and prevent the transition of acute low back pain to chronic low back pain

Dose Optimization for Single Intradiscal Administration of the Tumor Necrosis Factor-α Inhibitor, Etanercept, in Rat Disc Injury Models

Study DesignExperimental animal study.PurposeWe aimed to determine the optimal dose of a single direct injection of the tumor necrosis factor (TNF)-α inhibitor, etanercept, by using the rat model of degenerative intervertebral disc from injury.Overview of LiteratureThe pain-related peptide expression was suppressed in the etanercept (100 µg and 1,000 µg)-administered groups in a dose-dependent manner.MethodsThe neurotracer FluoroGold (FG) was applied to the surfaces of L4/5 discs to label their innervating dorsal root ganglion (DRG) neurons (n=50). Ten rats were included in the nonpunctured disc sham surgery control group, whereas the other 40 were included in the experimental group in which intervertebral discs were punctured with a 23-gauge needle. Saline or etanercept (10 µg, 100 µg, or 1,000 µg) was injected into the punctured discs (n=10 for each treatment). After 14 days of surgery, DRGs from L1 to L6 were harvested, sectioned, and immunostained for calcitonin gene-related peptide (CGRP). The proportion of FG-labeled CGRP-immunoreactive DRG neurons was evaluated in all the groups.ResultsThere were no significant differences between the puncture+saline group and the puncture+10-µg etanercept group (p >0.05). However, a significant decrease in the percentage of FG and CGRP double-positive cells in FG-positive cells was observed in the etanercept (100 µg and 1,000 µg)-administered groups in a dose-dependent manner (p <0.05).ConclusionsWhen a low dose of the TNF-α inhibitor (10 µg of etanercept) was directly administered to the rat intervertebral disc in the rat model of degenerative intervertebral disc from injury, no suppressive effect on the pain-related peptide expression was observed. However, when a higher dose of etanercept (100 µg and 1,000 µg) was administered, the pain-related peptide expression was suppressed in a dose-dependent manner

Correlation among Inflammatory Cytokine Expression Levels, Degree of Disk Degeneration, and Predominant Clinical Symptoms in Patients with Degenerated Intervertebral Discs

Study DesignObservational study.PurposeTo assess the correlation among inflammatory cytokine expression levels, degree of intervertebral disk (IVD) degeneration, and predominant clinical symptoms observed in degenerative disk disease (DDD).Overview of LiteratureLow back pain (LBP) is associated with inflammatory cytokine expression levels, including those of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), and nerve growth factor (NGF). However, the association between cytokine expression levels and the physiological mechanisms of disk degeneration and clinical pain remain controversial.MethodsUsing the enzyme-linked immunosorbent assay, TNF-α, IL-6, and NGF expression levels were analyzed in 58 IVD samples that were harvested from patients with lumbar DDD. Patient samples were grouped according to the degree of IVD degeneration using the Pfirrmann grading system and magnetic resonance imaging, and the correlations between the disease groups and each cytokine expression level were assessed. In addition, on the basis of their predominant preoperative symptoms, the patients were assigned to either an LBP or leg pain group to determine the correlation among these disease manifestations and individual cytokine expression levels.ResultsA gradual increase in TNF-α (R=0.391) and IL-6 (R=0.388) expression levels correlated with the degree of IVD degeneration, whereas NGF (R=0.164) expression levels exhibited a minimal decrease with disease progression. Regarding the predominant clinical manifestation, only the LBP group exhibited a significant increase in TNF-α expression levels (p=0.002).ConclusionsThese results suggested that TNF-α and IL-6 play an important role in the pathophysiology of IVD degeneration at any stage, whereas NGF plays an important role during the early disease stages. Moreover, because TNF-α expression levels were significantly high in the LBP group, we propose that they are involved in LBP onset or progression

Inhibiting Vascular Endothelial Growth Factor in Injured Intervertebral Discs Attenuates Pain-Related Neuropeptide Expression in Dorsal Root Ganglia in Rats

Study DesignAn experimental animal study.PurposeTo evaluate effects of anti-vascular endothelial growth factor (VEGF) on the content and distribution of the calcitonin gene-related peptide (CGRP) in the dorsal ganglia in a rat model.Overview of LiteratureIncreased expression of VEGF in degenerative disc disease increases the levels of inflammatory cytokines and nerve ingrowth into the damaged discs. In animal models, increased levels of VEGF can persist for up to 2 weeks after an injury.MethodsThrough abdominal surgery, the dorsal root ganglia (DRG) innervating L5/L6 intervertebral disc were labeled (FluoroGold neurotracer) in 24, 8-week old Sprague Dawley rats. The rats were randomly allocated to three groups of eight rats each. The anti-VEGF group underwent L5/6 intervertebral disc puncture using a 26-gauge needle, intradiscal injection of 33.3 µg of the pegaptanib sodium, a VEGF165 aptamer. The control-puncture group underwent disc puncture and intradiscal injection of 10 µL saline solution, and the sham-surgery group underwent labeling but no disc puncture. Two rats in each group were sacrificed on postoperative days 1, 7, 14, and 28 after surgery. L1–L6 DRGs were harvested, sectioned, and immunostained to detect the content and distribution of CGRP.ResultsCompared with the control, the percentage of CGRP-positive cells was lower in the anti-VEGF group (p<0.05; 40.6% and 58.1% on postoperative day 1, 44.3% and 55.4% on day 7, and 42.4% and 59.3% on day 14). The percentage was higher in the control group compared with that of the sham group (p<0.05; sham group, 34.1%, 40.7%, and 33.7% on postoperative days 1, 7, and 14, respectively).ConclusionsDecreasing CGRP-positive cells using anti-VEGF therapy provides fundamental evidence for a possible therapeutic role of anti-VEGF in patients with discogenic lower back pain

Disentangling the complex gene interaction networks between rice and the blast fungus identifies a new pathogen effector

Studies focused solely on single organisms can fail to identify the networks underlying host–pathogen gene-for-gene interactions. Here, we integrate genetic analyses of rice (Oryza sativa, host) and rice blast fungus (Magnaporthe oryzae, pathogen) and uncover a new pathogen recognition specificity of the rice nucleotide-binding domain and leucine-rich repeat protein (NLR) immune receptor Pik, which mediates resistance to M. oryzae expressing the avirulence effector gene AVR-Pik. Rice Piks-1, encoded by an allele of Pik-1, recognizes a previously unidentified effector encoded by the M. oryzae avirulence gene AVR-Mgk1, which is found on a mini-chromosome. AVR-Mgk1 has no sequence similarity to known AVR-Pik effectors and is prone to deletion from the mini-chromosome mediated by repeated Inago2 retrotransposon sequences. AVR-Mgk1 is detected by Piks-1 and by other Pik-1 alleles known to recognize AVR-Pik effectors; recognition is mediated by AVR-Mgk1 binding to the integrated heavy metal-associated (HMA) domain of Piks-1 and other Pik-1 alleles. Our findings highlight how complex gene-for-gene interaction networks can be disentangled by applying forward genetics approaches simultaneously to the host and pathogen. We demonstrate dynamic coevolution between an NLR integrated domain and multiple families of effector proteins

Uncertainty-driven growth

In this paper, I present a model in which firm-level uncertainty raises aggregate productivity growth. The mechanism for this is learning-by-doing in the research sector: firms undertake research to reduce uncertainty, which results in social knowledge accumulation that improves the productivity of future research. The model explains the positive correlation between TFP growth and dispersion in manufacturing industries.Firm-level uncertainty Knowledge accumulation TFP growth and dispersion Bayesian updating

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Modelos de regressão em cristas, embora possam ser considerados como casos particulares do modelo de regressão linear geral, apresentam características próprias e problemas específicos. São geralmente utilizados para contornar o problema da multicolinearidade, conseqüência da existência de relações lineares entre as variáveis explicativas. No presente trabalho nos dedicamos, inicialmente, à discussão do problema da multicolinearidade induzida por pontos discrepantes. Serão analisados alguns procedimentos para auxiliar a identificação de multicolinearidade gerada por pontos discrepantes. Medidas de influência adaptadas ao contexto de regressão em cristas serão apresentadas, bem como medidas de influência local. O modelo robusto em cristas será abordado e, finalmente, alguns dos procedimentos descritos serão aplicados em um conjunto de dados reais.not availabl