Process Parameter Optimization for Laser Powder Bed Fusion of Fe-Si Alloy Considering Surface Morphology and Track Width of Single Scan Track.

A laser power bed fusion (L-PBF) manufacturing process was optimized by analyzing the surface morphology and track width w of single scan tracks (SSTs) on Fe-3.4wt.%Si. An SST was evaluated under process conditions of laser power P, scan speed V, and energy density E = P/V. The SST surface shape was mainly affected by E; desirable thin and regular tracks were obtained at E = 0.3 and 0.4 J/mm. An L-PBF process window was proposed considering the optimal w of SST, and the appropriate range of E for the alloy was identified to be 0.24 J/mm to 0.49 J/mm. w showed a strong relationship with E and V, and an analytic model was suggested. To verify the process window derived from the appropriate w of SST, cubic samples were manufactured with the estimated optimal process conditions. Most samples produced had a high density with a porosity of <1%, and the process window derived from SST w data had high reliability. This study presents a comprehensive approach to enhancing additive manufacturing for Fe-3.4Si alloy, offering valuable insights for achieving high-quality samples without the need for time-intensive procedures.

Effect of Internal Pores Formed by a Superabsorbent Polymer on Durability and Drying Shrinkage of Concrete Specimens.

In this study, the effect of internal pores formed by a superabsorbent polymer (SAP) was analyzed by evaluating the compressive strength, chloride penetration depth, drying shrinkage, and pore size distribution of SAP-containing concrete, while securing workability using a water-reducing agent (WRA). The experimental results showed that the amount of WRA necessary increased as the amount of SAP added increased, and that the compressive strength was the highest when the SAP content was 1.5% of the concrete mix. Drying shrinkage tended to decrease as the SAP content increased, and it decreased by approximately 31-41% when the SAP content was 2.0% compared to that of the reference mix. The SAP expanded by approximately three times inside concrete, and it was distributed within the internal pores of air-entrained concrete. The optimal SAP content in concrete mix was 1.5%, and an SAP content of 2.0% or higher adversely affected the workability and compressive strength.

Data analytics approach for melt-pool geometries in metal additive manufacturing.

Modern data analytics was employed to understand and predict physics-based melt-pool formation by fabricating Ni alloy single tracks using powder bed fusion. An extensive database of melt-pool geometries was created, including processing parameters and material characteristics as input features. Correlation analysis provided insight for relationships between process parameters and melt-pools, and enabled the development of meaningful machine learning models via the use of highly correlated features. We successfully demonstrated that data analytics facilitates understanding of the inherent physics and reliable prediction of melt-pool geometries. This approach can serve as a basis for the melt-pool control and process optimization.

Therapeutic decision-making in elderly patients with acute myeloid leukemia: conventional intensive chemotherapy versus hypomethylating agent therapy.

Standards of care for elderly acute myeloid leukemia (AML) patients unfit for intensive chemotherapy remain undefined. We aimed to compare outcomes of hypomethylating agent (HMA) therapy and intensive chemotherapy (IC) in elderly AML patients and identify the subgroup of patients who are eligible for HMA therapy. We reviewed data on the outcomes of 86 AML patients aged ≥ 65 years, who had undergone treatment between 2010 and 2015. These treatments included IC (25 patients, 29.1%) or therapy using HMA including azacitidine or decitabine (61 patients, 70.9%). The overall response rates were 32 and 19.7%, respectively. Median overall survival (OS) (8 vs. 8 months) and progression-free survival (PFS) (6 vs. 7 months) durations were similar in the two groups. Patients in the HMA group with less than 10% peripheral blood (PB) blasts achieved significantly better OS duration than patients in the IC group (P = 0.043). Patients in the IC group with PB blasts and bone marrow blast of ≥ 10 and ≥ 50%, respectively, achieved better PFS durations than the corresponding patients in the HMA group (P = 0.038). Multivariate analysis identified the hematologic improvement-platelet (HI-P) as an independent prognostic factor for survival in the HMA group (P = 0.005). Our results showed that HMA therapy and IC were associated with similar survival duration in elderly AML patients. This study was noteworthy because it assessed prognostic factors that would help to select elderly patients who could expect actual benefits from undergoing the different therapeutic options available, especially HMA therapy.

Ternary Blend Composed of Two Organic Donors and One Acceptor for Active Layer of High-Performance Organic Solar Cells.

Ternary blends composed of two donor absorbers with complementary absorptions provide an opportunity to enhance the short-circuit current and thus the power conversion efficiency (PCE) of organic solar cells. In addition to complementary absorption of two donors, ternary blends may exhibit favorable morphology for high-performance solar cells when one chooses properly the donor pair. For this purpose, we develop a ternary blend with two donors (diketopyrrolopyrrole-based polymer (PTDPP2T) and small molecule ((TDPP)2Ph)) and one acceptor (PC71BM). The solar cell made of a ternary blend with 10 wt % (TDPP)2Ph exhibits higher PCE of 7.49% as compared with the solar cells with binary blends, PTDPP2T:PC71BM (6.58%) and (TDPP)2Ph:PC71BM (3.21%). The higher PCE of the ternary blend solar cell is attributed mainly to complementary absorption of two donors. However, a further increase in (TDPP)2Ph content in the ternary blend (>10 wt %) decreases the PCE. The ternary blend with 10 wt % (TDPP)2Ph exhibits well-developed morphology with narrow-sized fibrils while the blend with 15 wt % (TDPP)2Ph shows phase separation with large-sized domains, demonstrating that the phase morphology and compatibility of ternary blend are important factors to achieve a high-performance solar cell made of ternary blends.

Wogonin, a plant flavone from Scutellariae radix, attenuated ovalbumin-induced airway inflammation in mouse model of asthma via the suppression of IL-4/STAT6 signaling.

Bronchial asthma is a chronic inflammatory disease of the airways characterized by a marked infiltration of eosinophils at the site of inflammation. Eotaxins are potent chemoattractants for eosinophils and play important roles in pathogenesis of asthma. In the course of screening for eotaxin-3 inhibitors, we found that wogonin showed potent inhibitory activity of interleukin-4 (IL-4)-induced eotaxin-3 expression in BEAS-2B cells. In this study, we examined the effects of wogonin on IL-4/STAT6 signaling pathway and biological implication in a mouse model of asthma. Wogonin inhibited IL-4-induced activation and nuclear translocation of STAT6 which plays a key role in either the transcription of STAT6-response genes or Th2 cytokine-mediated inflammation. Oral administration of wogonin significantly reduced activation of STAT6 in the lung and the expression of eotaxin and RANTES in bronchoalveolar lavage fluids. Histological examination of lung tissue demonstrated that wogonin significantly inhibited allergen-induced eosinophilic inflammation. Administration of wogonin reduced the total IgE and ovalbumin-specific IgE levels compared with the ovalbumin-challenged group. All of these data demonstrated that wogonin could alleviate airway inflammation through inhibition of STAT6 activation induced by Th2 cytokines. Our finding implicates a potential therapeutic value of wogonin in the treatment of asthma through regulation of IL-4/STAT6 signaling pathway.

Small molecules based on thieno[3,4-c]pyrrole-4,6-dione for high open-circuit voltage (VOC) organic photovoltaics: effect of different positions of alkyl substitution on molecular packing and photovoltaic performance.

Two different thienopyrroledione (TPD)-based small molecules (SMs) with different alkyl substitution positions were synthesized, and their photovoltaic properties are measured and compared to examine the effect of the alkyl substitution position on their optical, electrochemical, and photovoltaic properties. The use of TPD as an electron-accepting unit in conjugated SMs effectively lowers the highest occupied molecular orbital (HOMO) energy levels of the conjugated SMs and leads to high open-circuit voltage (VOC). The two SMs with n-hexyl group substituted at different positions exhibit almost identical optical and electrochemical properties in the pristine state. However, the crystallographic and morphological characteristics of the two SMs are significantly different, because they are blended with PC71BM. The SM in which n-alkyl groups are substituted at the central accepting unit exhibits a power conversion efficiency (PCE) of 6.0% with VOC=0.94 V, which is among the highest PCE values of TPD-based SM devices, whereas the SM with n-alkyl groups being substituted at the chain ends shows a moderate PCE value of 3.1%.

Transaxillary subpectoral implantation of implantable pulse generator for deep brain stimulation.

OBJECTIVES: Deep brain stimulation (DBS) is an effective modality of treating cardinal motor symptoms of several movement disorders such as Parkinson's disease, essential tremor, and dystonia. Although hardware-related complications of DBS have been reported, the cosmetic satisfaction and discomfort associated with infraclavicular subcutaneous implantation of the pulse generator has not been described. The authors adopted a technique of transaxillary subpectoral implantable pulse generator (IPG) placement and investigated the difference in the discomfort, cosmetic satisfaction, mean operation time for IPG implantation, and severity of postoperative pain between infraclavicular subcutaneous placement and transaxillary subpectoral implantation of IPG. MATERIALS AND METHODS: 25 patients who underwent bilateral, infraclavicular subcutaneous IPG placement for DBS and 15 patients who had bilateral, transaxillary subpectoral IPG placement were investigated. RESULTS: The differences in cosmetic satisfaction and discomfort between the two groups were significant. The cosmetic satisfaction was higher and discomfort was less in the subpectoral IPG implantation group (p = 0.002 and p = 0.000). However, more time was needed for IPG implantation, and the postoperative pain was more severe after subpectoral IPG implantation (p = 0.002 and p = 0.000). There was no difference in cosmetic satisfaction according to sex (p = 0.907). There was one transient intercostobrachial nerve injury in the subpectoral IPG implantation group and two infections which needed removal of one side of the DBS hardware in the infraclavicular IPG implantation group. CONCLUSIONS: These results demonstrated that subpectoral transaxillary IPG implantation can provide better cosmetic satisfaction in patients undergoing DBS, with less discomfort and morbidity related to erosion and infection.

A warm footbath improves coronary flow reserve in patients with mild-to-moderate coronary artery disease.

BACKGROUNDS: Recent studies have shown that thermal therapy by means of warm waterbaths and sauna has beneficial effects in chronic heart failure. However, a comprehensive investigation of the hemodynamic effects of thermal vasodilation on coronary arteries has not been previously undertaken. In this study, we studied the effect of a warm footbath (WFB) on coronary arteries in patients with coronary artery disease (CAD), as well as any adverse effect. METHODS: We studied 21 patients (33.3% men, mean age 60.8 ± 13.5 years) with CAD. Coronary flow Doppler examination of the left anterior descending coronary artery and coronary flow reserve (CFR) were performed and measured using adenosine before and after a WFB. RESULTS: Systolic and diastolic blood pressure and heart rate did not change with the WFB. Mean velocity of diastolic coronary flow significantly increased (diastolic mean flow velocity: 18.3 ± 7.1 cm/sec initial, 21.5 ± 8.0 cm/sec follow-up, P = 0.002) and CFR significantly improved (1.6 ± 0.4 vs. 2.2 ± 0.5, P < 0.001) after WFB. The WFB was well accepted and no relevant adverse effects were observed. The change of CFR after WFB correlated well with diastolic function (E', r = 0.51, P = 0.031; E/E', r =-0.675, P = 0.002). CONCLUSIONS: A WFB significantly improved CFR without any adverse effects in patients with mild-to-moderate CAD and can be applied with little risk of a coronary artery event if appropriately performed.