21 research outputs found
Efficacy and prognosis following combined cinepazaide maleate/nimodipine therapy in cerebral vasospasm patients after hemorrhage
Purpose: To investigate the efficacy and prognosis following treatment of cerebral vasospasm (CVS) patients with a combination of cinnarizide maleate and nimodipine after subarachnoid hemorrhage (SAH).Methods: Eighty-eight patients with CVS after SAH were selected and divided into control group (CG) and study group (EG), each with 44 patients (n = 44). Patients in CG were treated with intravenous infusion of cinnarizide maleate, while those in EG received intravenous infusion of cinnarizide maleate together, and their clinical efficacy and prognosis were compared.Results: Compared with CG, total treatment effectiveness (response) in EG was significantly higher, while levels of inflammatory factors were lower (p < 0.05). Serum protein levels of S100 Ī² and ET-1, and MCA blood flow velocity in EG were notably lower (p < 0.05), but GCS scores were highercompared with CG (p < 0.05). The NIHSS scores were lower and BI indices were higher in EG than in CG (p < 0.05).Conclusion: Treatment of CVS patients after SAH using a combination of cinnarizide maleate and nimodipine effectively reduces the levels of inflammatory factors, improves quality of prognosis, and relieves symptoms of CVS, when compared with administration of cinnarizide maleate only. Therefore, the combination treatment is recommended for the management of CVS after SAH
Low-power/high-gain flexible complementary circuits based on printed organic electrochemical transistors
The ability to accurately extract low-amplitude voltage signals is crucial in
several fields, ranging from single-use diagnostics and medical technology to
robotics and the Internet of Things. The organic electrochemical transistor,
which features large transconductance values at low operation voltages, is
ideal for monitoring small signals. Its large transconductance translates small
gate voltage variations into significant changes in the drain current. However,
a current-to-voltage conversion is further needed to allow proper data
acquisition and signal processing. Low power consumption, high amplification,
and manufacturability on flexible and low-cost carriers are also crucial and
highly anticipated for targeted applications. Here, we report low-power and
high-gain flexible circuits based on printed complementary organic
electrochemical transistors (OECTs). We leverage the low threshold voltage of
both p-type and n-type enhancement-mode OECTs to develop complementary voltage
amplifiers that can sense voltages as low as 100 V, with gains of 30.4 dB
and at a power consumption < 2.7 W (single-stage amplifier). At the
optimal operating conditions, the voltage gain normalized to power consumption
reaches 169 dB/W, which is > 50 times larger than state-of-the-art
OECT-based amplifiers. In a two-stage configuration, the complementary voltage
amplifiers reach a DC voltage gain of 193 V/V, which is the highest among
emerging CMOS-like technologies operating at supply voltages below 1 volt. Our
findings demonstrate that flexible complementary circuits based on printed
OECTs define a power-efficient platform for sensing and amplifying
low-amplitude voltage signals in several emerging beyond-silicon applications
Damage constitutive model of lunar soil simulant geopolymer under impact loading
Lunar base construction is a crucial component of the lunar exploration program, and considering the dynamic characteristics of lunar soil is important for moon construction. Therefore, investigating the dynamic properties of lunar soil by establishing a constitutive relationship is critical for providing a theoretical basis for its damage evolution. In this paper, a split Hopkinson pressure bar (SHPB) device was used to perform three sets of impact tests under different pressures on a lunar soil simulant geopolymer (LSSG) with sodium silicate (Na2SiO3) contents of 1%, 3%, 5% and 7%. The dynamic stressāstrain curves, failure modes, and energy variation rules of LSSG under different pressures were obtained. The equation was modified based on the ZWT viscoelastic constitutive model and was combined with the damage variable. The damage element obeys the Weibull distribution and the constitutive equation that can describe the mechanical properties of LSSG under dynamic loading was obtained. The results demonstrate that the dynamic compressive strength of LSSG has a marked strain-rate strengthening effect. Na2SiO3 has both strengthening and deterioration effects on the dynamic compressive strength of LSSG. As Na2SiO3 grows, the dynamic compressive strength of LSSG first increases and then decreases. At a fixed air pressure, 5% Na2SiO3 had the largest dynamic compressive strength, the largest incident energy, the smallest absorbed energy, and the lightest damage. The ZWT equation was modified according to the stress response properties of LSSG and the range of the SHPB strain rate to obtain the constitutive equation of the LSSG, and the model's correctness was confirmed
Enhancement of Gas Sensing Characteristics of Multiwalled Carbon Nanotubes by CF4 Plasma Treatment for SF6 Decomposition Component Detection
H2S and SO2 are important gas components of decomposed SF6 of partial discharge generated by insulation defects in gas-insulated switchgear (GIS). Therefore, H2S and SO2 detection is important in the state evaluation and fault diagnosis of GIS. In this study, dielectric barrier discharge was used to generate CF4 plasma and modify multiwalled carbon nanotubes (MWNTs). The nanotubes were plasma-treated at optimum discharge conditions under different treatment times (0.5, 1, 2, 5, 8, 10, and 12āmin). Pristine and treated MWNTs were used as gas sensors to detect H2S and SO2. The effects of treatment time on gas sensitivity were analyzed. Results showed that the sensitivity, response, and recovery time of modified MWNTs to H2S were improved, but the recovery time of SO2 was almost unchanged. At 10āmin treatment time, the MWNTs showed good stability and reproducibility with better gas sensing properties compared with the other nanotubes
ZIF-67-Derived Flexible Sulfur Cathode with Improved Redox Kinetics for High-Performance Li-S Batteries
Lithiumāsulfur (Li-S) batteries have received much attention due to their high energy density and low price. In recent years, alleviating the volume expansion and suppressing the shuttle effect during the charge and discharge processes of Li-S batteries have been widely addressed. However, the slow conversion kinetics from polysulfide (LiPSs) to Li2S2/Li2S still limits the application of Li-S batteries. Therefore, we designed a ZIF-67 grown on cellulose (named ZIF-67@CL) as an electrocatalyst to improve the interconversion kinetics from LiPSs to Li2S2/Li2S for Li-S batteries. Based on the results of adsorption experiments of LiPSs, ZIF-67@CL and CL hosts were immersed in Li2S4 solution to adsorb LiPSs, and the UV-Vis test was conducted on the supernatant after adsorption. The results showed that the ZIF-67@CL had a stronger adsorption for LiPSs compared with the cellulose (CL). Furthermore, in the Li2S nucleation tests, the fabricated cells were galvanostatically discharged to 2.06 V at 0.112 mA and then potentiostatically discharged at 2.05 V. Based on the results of Li2S nucleation tests, the catalytic effect of ZIF-67 was further verified. As a result, the sulfur cathode used a ZIF-67 catalyst (named S/ZIF-67@CL) and delivered an initial capacity of 1346 mAh gā1 at a current density of 0.2 C. Even at a high current density of 2 C, it exhibited a high-capacity performance of 1087 mAh gā1 on the first cycle and maintained a capacity output of 462 mAh gā1 after 150 cycles, with a Coulombic efficiency of over 99.82%
Determination of Bitterness of <i>Andrographis Herba</i> Based on Electronic Tongue Technology and Discovery of the Key Compounds of Bitter Substances
Andrographis Herba (AH), the dry aerial segments of Andrographis paniculata (Burm.f.) Nees, is a common herbal remedy with bitter properties in traditional Chinese medicine (TCM) theory. Although bitterness is one of the features representing Chinese medicine, it has not been implemented as an index to assess the quality and efficacy of TCM because of peoples’ subjectivity to taste. In this study, 30 batches of AH with different commercial classifications (leaves, stems, or mixtures of both) were collected. Bitterness of AH was quantified by electronic tongue technology. Meanwhile, chemical compositions were characterized through establishing high-performance liquid chromatography fingerprints. The result indicated that the radar curves of the bitterness from different AH commercial classifications displayed different taste fingerprint information. Based on six taste factors, a Principal Component Analysis (PCA) score three-dimensional (3D) plot exhibited a clear grouping trend (R2X, 0.912; Q2, 0.763) among the three different commercial classifications. Six compounds (Peaks 2, 3, 4, 6, 7, 8) with positive correlation to bitterness were discovered by a Spearman correlation analysis. Peaks 2, 6, 7, 8 were identified as andrographolide, neoandrographolide, 14-deoxyandrographolide, and dehydroandrographolide, respectively. The electronic tongue can be used to distinguish AH samples with different commercial classifications and for quality evaluation
Construction of Topological Macromolecular Side Chains Packing Model: Study Unique Relationship and Differences in LC-Microstructures and Properties of Two Analogous Architectures with Well-Designed Side Attachment Density
A new series of linearācomb
and 4-arm starācomb side
chain liquid crystalline polymers (Lc-/Sc-SCLCPs) have been synthesized
and characterized. The treatment of hydride siloxane-containing terminated
liquid crystalline and high 1,2-/1,4- (high vinyl, hv/low vinyl, lv)
linear or 4-arm star polybutadienes (L-/S-PBs) was conducted via the
methods in combination of living anionic polymerization and āreverseā
hydrosilylation to obtain SCLCPs with wide mesomorphic temperature
range (Ī<i>T</i>) and narrow polydispersity index
(PDI). The possible molecular arrangement model of two analogous hv-/lv-architectures
was constructed, that was used to systematically investigate the effects
of Lc- and Sc- topological morphology on liquid crystalline (LC) properties
and molecular microstructures. SCLCPs exhibited the same smectic A
phase around room temperature, but thermal properties were significantly
different due to differences of interaction force resulting from different
macromolecular side chains packing. Surprisingly, the trend of lv-SCLCP
displaying the effects of topology on phase transitions and microstructures
was just contrary to that of hv-topology. hv-Sc-SCLCPs containing
high density mesogenic composition were desired to generate wider
Ī<i>T</i> and higher molecular layer order in comparison
with Lc analogues, which provided a unexpected analyzed model that
are of interest to be explored. In particular, the uniaue differences
of macromolecular aggregation state arrangement in liquid crystal
state dependent on free cooling between hv-Lc- and Sc-SCLCPs were
observed from POM
In Situ Spectroscopic and Electrical Investigations of Ladder-type Conjugated Polymers Doped with Alkali Metals
Ladder-type conjugated polymers exhibit a remarkable performance in (opto)electronic devices. Their double-stranded planar structure promotes an extended pi-conjugation compared to inter-ring-twisted analogues, providing an excellent basis for exploring the effects of charge localization on polaron formation. Here, we investigated alkali-metal n -doping of the ladder-type conjugated polymer (polybenzimidazobenzophe-nanthroline) (BBL) through detailed in situ spectroscopic and electrical characterizations. Photoelectron spectroscopy and ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy indicate polaron formation upon potassium (K) doping, which agrees well with theoretical predictions. The semiladder BBB displays a similar evolution in the valence band with the appearance of two new features below the Fermi level upon K-doping. Compared to BBL, distinct differences appear in the UV-vis-NIR spectra due to more localized polaronic states in BBB. The high conductivity (2 S cm(-1)) and low activation energy (44 meV) measured for K-doped BBL suggest disorder-free polaron transport. An even higher conductivity (37 S cm(-1)) is obtained by changing the dopant from K to lithium (Li). We attribute the enhanced conductivity to a decreased perturbation of the polymer nanostructure induced by the smaller Li ions. These results highlight the importance of polymer chain planarity and dopant size for the polaronic state in conjugated polymers.Funding Agencies|Swedish Research Council [2016 - 05498, 2016 - 05990, 2020 - 04538, 2018 - 06048]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkping University [2009 00971]; US National Science Foundation [DMR-2003518]</p
Ion-tunable antiambipolarity in mixed ion-electron conducting polymers enables biorealistic organic electrochemical neurons
Biointegrated neuromorphic hardware holds promise for new protocols to record/regulate signalling in biological systems. Making such artificial neural circuits successful requires minimal device/circuit complexity and ion-based operating mechanisms akin to those found in biology. Artificial spiking neurons, based on silicon-based complementary metal-oxide semiconductors or negative differential resistance device circuits, can emulate several neural features but are complicated to fabricate, not biocompatible and lack ion-/chemical-based modulation features. Here we report a biorealistic conductance-based organic electrochemical neuron (c-OECN) using a mixed ion-electron conducting ladder-type polymer with stable ion-tunable antiambipolarity. The latter is used to emulate the activation/inactivation of sodium channels and delayed activation of potassium channels of biological neurons. These c-OECNs can spike at bioplausible frequencies nearing 100 Hz, emulate most critical biological neural features, demonstrate stochastic spiking and enable neurotransmitter-/amino acid-/ion-based spiking modulation, which is then used to stimulate biological nerves in vivo. These combined features are impossible to achieve using previous technologies.Funding Agencies|Linkoeping University</p
Influence of Molecular Weight on the Organic Electrochemical Transistor Performance of Ladder-Type Conjugated Polymers
Organic electrochemical transistors (OECTs) hold promise for developing a variety of high-performance (bio-)electronic devices/circuits. While OECTs based on p-type semiconductors have achieved tremendous progress in recent years, n-type OECTs still suffer from low performance, hampering the development of power-efficient electronics. Here, it is demonstrated that fine-tuning the molecular weight of the rigid, ladder-type n-type polymer poly(benzimidazobenzophenanthroline) (BBL) by only one order of magnitude (from 4.9 to 51 kDa) enables the development of n-type OECTs with record-high geometry-normalized transconductance (g(m,norm) approximate to 11 S cm(-1)) and electron mobility x volumetric capacitance (mu C* approximate to 26 F cm(-1) V-1 s(-1)), fast temporal response (0.38 ms), and low threshold voltage (0.15 V). This enhancement in OECT performance is ascribed to a more efficient intermolecular charge transport in high-molecular-weight BBL than in the low-molecular-weight counterpart. OECT-based complementary inverters are also demonstrated with record-high voltage gains of up to 100 V V-1 and ultralow power consumption down to 0.32 nW, depending on the supply voltage. These devices are among the best sub-1 V complementary inverters reported to date. These findings demonstrate the importance of molecular weight in optimizing the OECT performance of rigid organic mixed ionic-electronic conductors and open for a new generation of power-efficient organic (bio-)electronic devices.Funding Agencies|Knut and Alice Wallenberg foundationKnut & Alice Wallenberg Foundation; Swedish Research CouncilSwedish Research CouncilEuropean Commission [2016-03979, 2020-03243]; AForsk [18-313, 19-310]; Olle Engkvists Stiftelse [204-0256]; VINNOVAVinnova [2020-05223]; European Commission through the Marie Sklodowska-Curie project HORATES [GA-955837]; FET-OPEN project MITICS [GA-964677]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [SFO-Mat-LiU 2009-00971]; National Research Foundation of KoreaNational Research Foundation of Korea [NRF-2019R1A2C2085290, 2019R1A6A1A11044070]; National Science FoundationNational Science Foundation (NSF) [DMR-2003518]</p