Selective modification of native proteins in live cells is one of the central challenges in recent chemical biology. As a unique bioorthogonal approach, ligand-directed chemistry recently emerged, ...but the slow kinetics limits its scope. Here we successfully overcome this obstacle using N-acyl-N-alkyl sulfonamide as a reactive group. Quantitative kinetic analyses reveal that ligand-directed N-acyl-N-alkyl sulfonamide chemistry allows for rapid modification of a lysine residue proximal to the ligand binding site of a target protein, with a rate constant of ~10
M
s
, comparable to the fastest bioorthogonal chemistry. Despite some off-target reactions, this method can selectively label both intracellular and membrane-bound endogenous proteins. Moreover, the unique reactivity of N-acyl-N-alkyl sulfonamide enables the rational design of a lysine-targeted covalent inhibitor that shows durable suppression of the activity of Hsp90 in cancer cells. This work provides possibilities to extend the covalent inhibition approach that is currently being reassessed in drug discovery.
This study proposes a methodology to identify the modal damping ratio of a highly damped structure. Specifically, we explain the change in the modal damping ratio of the object itself by using an ...existing novel multiple excitation testing method with velocity feedback (FB) control to counteract the damping force, and we propose a methodology to identify the original modal damping ratio of the object based on the methodology of modal analysis. In this methodology, the relation equation between the modal damping ratio and control gain is derived. In the numerical and experimental validations, the modal damping ratio is identified by applying velocity FB excitation to a multi-degree-of-freedom system, and it is confirmed that the original modal damping ratio of the target structure can be identified from the frequency response function after damping reduction. Therefore, the proposed method is expected to improve experimental modal analysis by facilitating the accurate identification of the modal damping ratios of the vibration mode wherein the resonance peak does not appear clearly.
A long noncoding RNA, p21-associated ncRNA DNA damage-activated (PANDA), associates with nuclear transcription factor Y subunit alpha (NF-YA) and inhibits its binding to promoters of ...apoptosis-related genes, thereby repressing apoptosis in normal human fibroblasts. Here, we show that PANDA is involved in regulating proliferation in the U2OS human osteosarcoma cell line.
U2OS cells were transfected with siRNAs against PANDA 72 h later and they were subjected to reverse transcription-polymerase chain reaction (RT-PCR), quantitative RT-PCR and cell-cycle analysis.
PANDA was highly expressed in U2OS cells, and its expression was induced by DNA damage. Silencing PANDA caused arrest at the G
phase of the cell cycle, leading to inhibition of cell proliferation. Quantitative RT-PCR showed that silencing PANDA increased mRNA levels of the cyclin-dependent kinase inhibitor p18, which caused G
phase arrest.
These results suggest that PANDA promotes G
-S transition by repressing p18 transcription, and thus promotes U2OS cell proliferation.
We propose a novel voltage controller design procedure for voltage source inverters (VSIs) with uncertain loads, focusing on the passivity of loads. VSIs have been widely used in many applications. A ...VSI must regulate the load voltage to its sinusoidal reference quickly and accurately without distortion. It is essential to design a voltage controller that takes into account various load conditions since it is rarely known in advance what types of loads are connected to the VSI. In particular, it is challenging to suppress the voltage harmonic distortion caused by a nonlinear load, such as a diode rectifier, while achieving fast-tracking and zero steady-state error. A controller designed by the proposed procedure guarantees robust stability of the VSI independent of the load type and value. Namely, no information about uncertainties of load is needed to stabilize the VSI. Moreover, the proposed procedure realizes zero-steady state error, fast-tracking, and low distortion. We demonstrate the effectiveness of the proposed controller through comparative analysis with the proportional resonant (PR) and conventional robust controllers via simulations and experiments.
Abstract
Objective
Using a system, which accuracy is equivalent to the gold standard Douglas Bag (DB) technique for measuring oxygen consumption (VO
2
), carbon dioxide generation (VCO
2
), and ...respiratory quotient (RQ), we aimed to continuously measure these metabolic indicators and compare the values between post-cardiothoracic surgery and critical care patients.
Methods
This was a prospective, observational study conducted at a suburban, quaternary care teaching hospital. Age 18 years or older patients who underwent mechanical ventilation were enrolled.
Results
We included 4 post-surgery and 6 critical care patients. Of those, 3 critical care patients died. The longest measurement reached to 12 h and 15 min and 50 cycles of repeat measurements were performed. VO
2
of the post-surgery patients were 234 ± 14, 262 ± 27, 212 ± 16, and 192 ± 20 mL/min, and those of critical care patients were 122 ± 20, 189 ± 9, 191 ± 7, 191 ± 24, 212 ± 12, and 135 ± 21 mL/min, respectively. The value of VO
2
was more variable in the post-surgery patients and the range of each patient was 44, 126, 71, and 67, respectively. SOFA scores were higher in non-survivors and there were negative correlations of RQ with SOFA.
Conclusions
We developed an accurate system that enables continuous and repeat measurements of VO
2
, VCO
2
, and RQ. Critical care patients may have less activity in metabolism represented by less variable values of VO
2
and VCO
2
over time as compared to those of post-cardiothoracic surgery patients. Additionally, an alteration of these values may mean a systemic distinction of the metabolism of critically ill patients.
Nonstoichiometric direct arylation polycondensation of 2,2′,3,3′,5,5′,6,6′‐octafluorobiphenyl with excess of 2,7‐diiodo‐9,9‐dioctyl‐9H‐fluorene is demonstrated. Pd/Ag dual‐catalyst system under ...water/2‐methyltetrahydrofuran biphasic conditions enables direct arylation under mild conditions and promotes the intramolecular transfer of a Pd catalyst walking through the fluorene moiety. The nonstoichiometric direct arylation polycondensation under the optimized reaction conditions produces the corresponding π‐conjugated polymer with a high molecular weight and terminal octafluorobiphenyl units at both ends.
Nonstoichiometric direct arylation polycondensation of 2,2′,3,3′,5,5′,6,6′‐octafluorobiphenyl with excess 2,7‐diiodo‐9,9‐dioctyl‐9H‐fluorene is demonstrated. Pd/Ag dual‐catalyst system under water/2‐MeTHF biphasic conditions promotes intramolecular transfer of a Pd catalyst walking through the fluorene moiety, producing the corresponding π‐conjugated polymer with a terminal octafluorobiphenyl units at both ends and a high‐molecular weight.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
This study aimed to provide a novel and highly sensitive protein assay based on the biuret reaction and using chromeazurol B, a metal chelate compound. The method consists of two reagents and an ...automated analyzer. First, a complex of copper and protein (biuret reaction) is formed. Second, a chelating reagent containing chromeazurol B forms a three-dimensional complex of protein, copper, and chromeazurol B at neutral pH, resulting in highly sensitive coloration. The intra-assay (n = 20) variation for the three levels was 3.54 % or lower at each concentration. Each response with α, β-, and γ-globulin was 103.8 % and 104.3 %, respectively, against albumin. The molar absorption coefficient (ε) of the present method was 2.5 × 105 m2/mol against human albumin, higher than that of the commercially available Lowry method (ε = 8.7 × 104 m2/mol), which is based on the same principle. The correlation test for the pyrogallol method with 30 urine samples showed good performance (r = 0.961). The method described here (the Biuret-based CAB method) is a more sensitive and rapid assay than the Lowry method, and it may also be applied to biological samples because of its similar reactivity towards various proteins.
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•This method is a novel and highly sensitive protein assay based on the biuret reaction using Chromeazurol B, copper chelator.•The present method only has small differences in reactivity between proteins.•The present method can be applied to automated analyzers, which takes only 10 min for assay.•This study has demonstrated that our assay has the potential for application to biological samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
To develop a system that is equivalent to the gold standard Douglas Bag (DB) technique for measuring oxygen consumption (V̇o2), carbon dioxide generation (V̇co2), and respiratory quotient (RQ) and to ...validate its use in clinical settings.
This was a prospective, observational study conducted at a suburban, quaternary care teaching hospital. Healthy volunteers and patients 18 years or older who received mechanical ventilation were enrolled.
Data from 3 healthy volunteers and 7 patients were analyzed in this study. The interrater reliability between the automation device and DB methods were 0.999, 0.993, and 0.993 for V̇o2, V̇co2, and RQ, respectively. In healthy volunteers, mean (SD) V̇o2, V̇co2, and RQ measured by DB were 411 (100) mL/min, 288 (79) mL/min, and 0.70 (0.03) at high fraction of inspired oxygen (Fio2) and 323 (46) mL/min, 280 (45) mL/min, and 0.85 (0.05) at normal Fio2, respectively. V̇o2 was significantly higher (P < 0.05) and RQ was lower (P < 0.01) in the high Fio2 group as compared to those in the normal Fio2 group. Values measured by the automation system were 227 (31) mL/min, 141 (18) mL/min, and 0.62 (0.04) at high Fio2 and 209 (25) mL/min, 147 (18) mL/min, and 0.70 (0.06) at normal Fio2, respectively. RQ was significantly lower (P < 0.05) in the high Fio2 group as compared to the normal Fio2 group. We also successfully performed continuous and repeat measurements by using the device. The longest measurement reached 12 hours 15 minutes, including 50 cycles of repeat measurements that are equivalent to the DB technique as described above.
We developed an automation system that enables repeat measurements of V̇o2, V̇co2, and RQ, and the accuracy was equivalent to the DB technique. High Fio2 may decrease RQ because of an increase in V̇o2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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