This paper presents a new compact on-chip current-sensing circuit to enable current-mode buck regulators operating at a high switching frequency for reducing the inductor profile. A dynamically ...biased shunt feedback technique is developed in the proposed current sensor to push nondominant poles to higher frequencies, thereby improving the speed and stability of the current sensor under a wide range of load currents. A feedforward gain stage in the proposed current sensor also increases the dc loop-gain magnitude and thus enhances the accuracy of the current sensing. A current-mode buck regulator with the proposed current sensor has been implemented in a standard 0.35-μm CMOS process. Measurement results show that the proposed current sensor can achieve 95% sensing accuracy and <;; 50-ns settling time. The buck converter can thus operate properly at the switching frequency of 2.5 MHz with the duty cycle down to 0.3. The output ripple voltage of the regulator is <;; 43 mV with a 4.7-μF off-chip capacitor and a 2.2-μH off-chip inductor. The power efficiency of the buck regulator achieves above 80% over the load current ranging from 25 to 500 mA.
This paper presents a multi-MHz buck regulator for portable applications using an auto-selectable peak- and valley-current control (ASPVCC) scheme. The proposed ASPVCC scheme can enable the ...current-mode buck regulator to reduce the settling-time requirement of the current sensing by two times. In addition, the dynamically biased shunt feedback technique is employed to improve the sensing speed and the sensing accuracy of both the peak and valley current sensors. With both ASPVCC scheme and advanced current sensors, the buck regulator can thus operate at high switching frequencies with a wide range of duty ratios for reducing the required off-chip inductance. The proposed current-mode buck regulator was fabricated in a standard 0.35-μm CMOS process and occupies a small chip area of 0.54 mm 2 . Measurement results show that the buck regulator can deliver a maximum output current of 500 mA, operate at 5 MHz with a wide duty-ratio range of about 0.6, use a small-value off-chip inductor of 1 μH, and achieve the peak power efficiency of 91%.
Efficient isomerization of glucose into fructose contributes to the utilization of biomass producing 5-hydroxymethylfurfural (HMF). In this work, we have explored a novel catalyst for isomerization ...of glucose into fructose. By the mediation of polydopmaine (PDA), MnSn(OH)6 was formed on cryptomelane-type manganese oxide (OMS-2). The composite MnSn(OH)6/PDA@OMS-2 can efficiently catalyze the glucose isomerization to fructose, with a yield of fructose 47 ± 1.6%. When used together with the Brønsted acid catalyst Amberlyst-15, the HMF yield from glucose was 53 ± 2.5%. Consecutive use of the composite demonstrated that after eight cycles the activity can be retained in terms of the yield of fructose. The mechanism of polydopamine-mediated formation of MnSn(OH)6 has been investigated. The desired yield of fructose has been obtained by MnSn(OH)6/PDA@OMS-2, and the preparation of the catalyst has also shown advantages, including low cost and easy preparation, short preparation time (36 h), and low temperature (≤70 °C).
Background and objective:
Pruritus is a common complication in patients with primary biliary cholangitis (PBC). The pathogenesis is not clear, and also the precise therapeutic measures remain ...alluring. In order to systematically evaluate the efficacy and safety of drug interventions in the treatment of pruritus associated with PBC, this systemic review and meta-analysis was conducted.
Methods:
The randomized controlled trials (RCTs) on drug interventions in the treatment of pruritus associated with primary cholangitis were searched in the electronic databases of PubMed, EMBASE, Cochrane Library, Web of Science, and
ClinicalTrials.gov
. Two researchers independently screened the literature, extracted and integrated the data, and assessed the bias risk of the selected literature, according to the
Cochrane handbook
. Finally, the STATA 15.0 software was used for the meta-analysis.
Results:
A total of 23 RCTs involving 2,194 patients were studied, that included 12 pharmacological interventions. In terms of itching relief, compared with placebo, UDCA, methotrexate and GSK2330672 had a definite effect in improving pruritus (pruritus remission rate before and after treatment,
p <
0.05). In terms of serum indexes, compared with placebo group, UDCA, OCA, rifampicin, cyclosporine, NGM282, seladelpar and colchicine may improve blood alkaline phosphatase (ALP) (
p <
0.05), but only rifampicin showed low heterogeneity. UDCA, bezafibrate, OCA, rifampicin, NGM282 and others may improve blood γ-glutamyl transpeptidase (γ-GGT) (
p <
0.05), but due to the high heterogeneity and the limitation of research samples, a clear conclusion cannot be drawn. In terms of adverse events, except high (>15 mg/kg/day) and low doses (<13 mg/kg/day) of UDCA increased the incidence of adverse events, there were no risk of increasing the incidence of adverse events compared with placebo (
p >
0.05), and a moderate dose of UDCA (13–15 mg/kg/day) and malotilate (1,500 mg/day) may also help in reducing the incidence of adverse events (
p <
0.05).
Conclusion:
UDCA, methotrexate and GSK2330672 may relieve itching in patients with PBC, but there is a lack of robust evidence to support their effect on ALP or γ-GGT. Due to the heterogeneity in the published studies, based on the present review, we cannot explicitly recommend any specific drug for the treatment of PBC-related pruritus.
Systematic Review Registration:
link-https://osf.io/2g8ya
, identifier 10.17605/OSF.IO/2G8YA
Agriculture as a key industry for human food suply will face various concerns in near future. This research is complementary and aims to present the dynamic modelling and simulation, as well as ...algorithm development of a 4-DOF SCARA-type robotic arm designed for real agricultural cultivation process, such as seeding, watering, fertilizing, weeding, etc. In terms of a previously designed system, the equations of motion profile were solved (acceleration and deceleration control of joints) to reduce inertia, ensure a smooth motion, and minimize torque requirement. The algorithm is evaluated by PTP motion, TCP linear motion, and spline motion. The results show that the developed algorithm can move the TCP using ST-profile. Furthermore, it can control all joints for an estimated time duration. A novel method was developed to manoeuvre the TCP along the shortest path to reach a goal point. Finally, the algorithm was evaluated in a closed path inside the working space.
Topographic maps provide detailed information on variations in ground elevation, which is essential for precision farmland levelling. This paper reports the development and experimental study on an ...innovative approach of generating topographic maps at farmland-level with the advantages of high efficiency and simplicity of implementation. The experiment uses a low-altitude Unmanned Aerial Vehicle (UAV) as a platform and integrates Light Detection and Ranging (LiDAR) distance measurements with Post-Processing Kinematic Global Positioning System (PPK-GNSS) coordinates. A topographic mapping experiment was conducted over two fields in Henan Province, China, and primitive errors of the topographic surveying data were evaluated. The Root Mean Square Error (RMSE) between elevation data of the UAV-LiDAR topographic mapping system and ground truth data was calculated as 4.1 cm and 3.6 cm for Field 1 and Field 2, respectively, which proved the feasibility and high accuracy of the topographic mapping system. Furthermore, the accuracies of topographic maps generated using different geo-spatial interpolation models were also evaluated. The results showed that a TIN (Triangulated Irregular Network) interpolation model expressed the best performances for both Field 1 with sparse topographic surveying points, and Field 2 with relatively dense topographic surveying points, when compared with other interpolation models. Moreover, we concluded that as the spatial resolution of topographic surveying points is intensified from 5 m × 0.5 m to 2.5 m × 0.5 m, the accuracy of the topographic map based on the TIN model improves drastically from 7.7 cm to 4.6 cm. Cut-fill analysis was also implemented based on the topographic maps of the TIN interpolation model. The result indicated that the UAV-LiDAR topographic mapping system could be successfully used to generate topographic maps with high accuracy, which could provide instructive information for precision farmland levelling.
Pineal cysts have long been considered a benign intracranial variation. However, in our clinical practice, it has been observed that some children with central precocious puberty (CPP) who have ...pineal cysts experience rapid progression in adolescent development. In recent years, there has been a significant increase in the prevalence of CPP in girls, leading to more diagnoses of CPP among children with pineal cysts. Despite this, there is no consensus regarding whether pineal cysts contribute to CPP as one of its organic factors. This study aimed to analyze the clinical characteristics of pineal cysts in children with CPP and explore the potential effects of pineal cysts on puberty development.
This single-center study retrospectively analyzed clinical data from girls aged 3 to 10 years who underwent head/pituitary magnetic resonance imaging at the Children's Hospital Affiliated to Zhengzhou University between 2019 and 2022. The study categorized the detection rates of pineal cysts based on systematic disease classification and compared the rates of cyst detection between girls diagnosed with CPP and those without CPP. Subsequently, CPP-diagnosed girls with pineal cysts were examined. Among CPP-diagnosed girls meeting the study's criteria, those with pineal cysts formed the 'cyst group,' while those without cysts were matched in a 1:1 ratio based on age and body mass index to form the 'non-cyst group.' Comparative analyses were conducted to assess the clinical characteristics between these two groups. CPP-diagnosed girls with cysts were further subdivided into three groups according to cyst size (≤5 mm, 5.1-9.9 mm, and ≥10 mm) to investigate potential differences in clinical characteristics among these subgroups. The study involved an analysis of clinical data from girls diagnosed with CPP and included imaging follow-ups to explore the progression of pineal cysts over time.
Among the 23,245 girls who underwent head/pituitary magnetic resonance imaging scans, the detection rate of pineal cysts was 3.6% (837/23,245), with most cases being associated with endocrine diseases. The detection rate of pineal cysts in CPP patients was 6.4% (262/4099), which was significantly higher than the 3.0% (575/19,146) in patients without CPP. In comparison to the non-cyst group, the cyst group exhibited statistically significant increases in estradiol levels, peak luteinizing hormone (LH) levels, peak LH/follicle-stimulating hormone (FSH) ratios, uterine body length, and cervix length (P < 0.001). As cyst size increased, there were significant rises in LH peak, peak LH/FSH ratio, uterine body length, and cervical length (P < 0.01). Estradiol levels and left ovarian volume also showed an increasing trend (P < 0.05). Among girls who underwent follow-up imaging, 26.3% (5/19) exhibited an increase in cyst size.
Pineal cysts are relatively common in children with CPP. They may affect the pubertal development process, with larger cysts correlating to faster pubertal development. Therefore, the authors hypothesize that pineal cysts may trigger CPP in some cases, especially when the cysts are larger than 5 mm in size, as indicated by our data.
Photoreforming (PR) is a process that splits water into hydrogen coupled with oxidation of solid waste into value‐added products, which provides a way to mitigate resource depletion of solid waste ...and accumulation of CO2 in the atmosphere. The realization of solid waste PR by harnessing the redox capabilities of photocatalyst is crucial to address the environmental pollution issue and reduce our reliance on fossil fuels. In this review, we overview the continuous progress from the latest studies in constructing the PR system for upgrading of solid waste. We classify the different kinds of solid wastes and illustrate the PR mechanism. Furthermore, we discuss the advantages for cooperatively coupling of hydrogen production with solid waste valorization. We also highlight some state‐of‐the‐art photocatalysts for valorization of biomass, plastics, and food wastes. Finally, we focus on the development of high‐performance catalysts needed in the PR domain to tackle the future challenges.
Photoreforming (PR) of solid wastes integrates the benefits of hydrogen evolution and waste resource utilization while offering an opportunity to optimizing their respective performance. Specifically, solid wastes as feedstocks within the PR process accelerate the hydrogen evolution reaction via replacing the sluggish oxygen evolution reaction, and meanwhile contributes to the realization of value‐added chemicals through wastes oxidation.
The design of spinel-oxide-based catalysts with high activity and long-term durability for oxygen evolution reaction (OER) confronts grand challenges that may be well tackled by maneuvering the ...electronic structure of surface catalytic sites within spinel oxides. Herein, we harness a double exchange interaction (DEI) triggered by the synergistic effects of Schottky junction and oxygen vacancies (VO) to generate high proportions of octahedrally coordinated Ni3+ and Co2+ (highly active sites) in the edge-sharing NixCo1−XO6 octahedra. Specifically, Schottky junction is formed between metallic Cu nanowires and semiconducting NiCo2O4 via a core-shell structure, and abundant VO sites are created in NiCo2O4 via H2 thermal treatment. As expected, the Cu@VO-NiCo2O4 electrocatalyst allows a significantly boosted OER performance, with a low overpotential of 214 mV at 10 mA cm-2 and a small Tafel slope of 64.9 mV dec-1, which outperforms the state-of-the-art RuO2 catalyst and most of reported Ni-Co based OER catalysts. Our work provides some inspirations for designing high-performance spinel-oxide-based electrocatalysts towards OER via DEI engineering.
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•Double exchange interaction is induced by Schottky junction and oxygen vacancy.•Electron hopping occurs between mixed NiO6-CoO6 octahedral units.•Double exchange interaction contributes to the formation of octahedrally coordinated Ni3+ and Co2+ sites.•Octahedral Ni3+ and Co2+ sites synergistically improve the OER activity.
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