Effect of Fungus, Aspergillus sp. F1-1, on the Corrosion Behavior of PCB-HASL in Humid Atmospheric Environment

Fungi, as one of the serious factors causing microbiologically influenced corrosion (MIC), can shorten the service life of electronic materials which are wildly used in the atmospheric environment. In this study, the effect of Aspergillus sp. F1-1 (A. F1-1) isolated from PCB samples after the exposure test in Xishuang Banna on the corrosion behavior of PCB-HASL was investigated. The presence of the A. F1-1 posed a threat of local corrosion on PCB-HASLs. An obvious decrease of pH was observed in PCB with A. F1-1 due to the various organic acids secreted by A. F1-1. The presence of the fungi also led to serious surface cracking and delamination. Creep corrosion and micro-hole corrosion were accelerated in the presence of A. F1-1 compared to the control. Additionally, the metabolic activities of A. F1-1 were associated with enrichment of Cu-containing corrosion products under the hypha.

Effects of Iron-Oxide Nanoparticles (Fe3O4) Released From Synthesized Iron-based Thiourea Catalyst on the Growth, Cell Density, and Pigment Content of Chlorella Vulgaris

This study investigated the effects of Fe3O4 nanoparticles released from synthesized Thiourea catalyst to Chlorella vulgaris as an essential primary producer in aquatic systems. A range of Fe3O4 concentrations (0, 10, 100, 250, 500, 750, and 1000 mg L-1) was applied for the exposure test. Biological parameters of C. vulgaris, including cell density, cell viability, and pigment content were assessed. Bioconcentration factor and bioaccumulation were evaluated for contaminated microalgae. Non-carcinogenic risks were then assessed using target hazard quotient (THQ) for potential human consumptions. Findings showed that C. vulgaris cell numbers increased from 0 to 500 mg L-1 of Fe3O4. Chlorophyll a represented a time-dependent response, and greatest values were detected in 250 and 500 mg L-1 Fe3O4 at 4.2 and 4 mg/g, respectively. Chlorophyll b content showed a time-related manner in exposure to Fe3O4 with the highest values recorded at 250 mg L-1 after 96 h. Moreover, bioaccumulation displayed a dose-dependent response as bioaccumulated iron was in the largest amount at 15000 µg/g dw in 1000 mg L-1, whereas the lowest one was in the control group at 1700 µg/g dw. The bioconcentration factor showed a concentration-relevant decrease in all iron treatments and 10 mg L-1 of Fe3O4 represented the greatest BCF at 327.3611. Non-carcinogenic risks illustrated negligible hazard (THQ < 1) in a dose-response pattern and the largest EDI and THQ were calculated in 1000 mg L-1 at 7.4332E-07 (mg kg-1 day-1) and 1.06189E-09, respectively. In essence, iron is an essential trace element for biological aspects in aquatic systems, but in exceeding concentrations could impose toxicity effects in C. vulgaris populations.

Birnbaum-Saunders Durability Life Prediction Model of Site-Exposed Concrete in the Saline Soil Area

Aiming at the prominent problem of short durability life of concrete in saline soil area and the shortcomings of indoor accelerated test, an outdoor field exposure test was designed. The concrete specimens were semiburied in the Tianshui area with salinized soil characteristics, and nondestructive testing was conducted every 180d (days). The durability evaluation parameters and mechanical performance indexes were selected for macroscopic analysis, and the corrosion mechanism was analyzed by using the SEM image and the XRD phase. The Birnbaum-Saunders model based on physical failure and probability statistics was used for life prediction. The results show that there are rod-shaped and chip-shaped crystals growing from the surface of the gel and the internal holes in the exposed end and the embedded end of the concrete. However, the damage and deterioration of the buried end are more serious than those of the exposed end. The corrosion products mainly included ettringite, gypsum, calcium carbonate, sodium sulfate hydrate, carbosilite, and Friedel’s salt. The reliability life curve based on the Birnbaum-Saunders model can describe the whole process of exposed concrete from damage accumulation to failure. In addition, the dynamic modulus degradation index is more sensitive to concrete durability damage, and the life obtained by the Birnbaum-Saunders model is shorter than the quality degradation index. The life obtained by this degradation index is taken as the life of the concrete exposed in the saline soil site, and the concrete life of C30, C40, and C50 is about 3340d, 3930d, and 4360d, respectively.

Additive Effects of L-Ornithine on Preferences to Basic Taste Solutions in Mice

In addition to the taste receptors corresponding to the six basic taste qualities—sweet, salty, sour, bitter, umami, and fatty—another type of taste receptor, calcium-sensing receptor (CaSR), is found in taste-bud cells. CaSR is called the ‘kokumi’ receptor because its agonists increase sweet, salty and umami tastes to induce ‘koku’, a Japanese word meaning the enhancement of flavor characters such as thickness, mouthfulness, and continuity. Koku is an important factor for enhancing food palatability. However, it is not well known whether other kokumi-receptors and substances exist. Here, we show that ornithine (L-ornithine but not D-ornithine) at low concentrations that do not elicit a taste of its own, enhances preferences to sweet, salty, umami, and fat taste solutions in mice. Increased preference to monosodium glutamate (MSG) was the most dominant effect. Antagonists of G-protein-coupled receptor family C group 6 subtype A (GPRC6A) abolished the additive effect of ornithine on MSG solutions. The additive effects of ornithine on taste stimuli are thought to occur in the oral cavity, and are not considered post-oral events because ornithine’s effects were confirmed in a brief-exposure test. Moreover, the additive effects of ornithine and the action of the antagonist were verified in electrophysiological taste nerve responses. Immunohistochemical analysis implied that GPRC6A was expressed in subsets of type II and type III taste cells of mouse circumvallate papillae. These results are in good agreement with those reported for taste modulation involving CaSR and its agonists. The present study suggests that ornithine is a kokumi substance and GPRC6A is a newly identified kokumi receptor.

EXPERIMENTAL STUDY ON BEHAVIOR OF UNPROTECTED FOAMED CONCRETE FILLED STEEL HOLLOW COLUMN UNDER FIRE

Reduction in self-weight and achievement of full fire resistance requirements are some of the important considerations in the design of high-rise structures. Lightweight concrete filled steel tube (CFST) column provides an alternative method to serve these purposes. Recent studies on lightweight CFST columns at ambient temperature have revealed that foamed concrete can be a beneficial and innovative alternative material. Hence, this study investigates the potential of using foamed concrete in circular hollow steel columns for improving fire resistance. A series of nine fire test on circular unfilled hollow and foamed concrete filled hollow section column were carried out. ISO 834 standard fire exposure test were carried out to investigate the structural response of these columns under fire. The main parameters considered are load level and foamed concrete density; foamed concrete density used are 1500 kg/m3 and 1800 kg/m3 at 15%, 20%, and 25% load level. All the columns tested are without any external fire protection, with concentrically applied load under fixed-fixed boundary conditions. The columns dimension was 2400 mm long, 139.7 mm diameter and steel tube thickness of 6 mm. The fire test result showed that foamed concrete increases the fire resistance of steel hollow column up to an additional 16 minutes. The improvement is more at load level above 15%, and the gain in fire resistance is about 71% when 1500 kg/m3 density foamed concrete is used. Generally, foamed concrete filled steel hollow column demonstrate a good structural fire behavior, based on the applied load and foamed concrete density. Also, inward local buckling was averted by filling the steel hollow column with foamed concrete. General method for composite column design in Eurocode 4 adopted to calculate the axial buckling load of 1500 kg/m3 foamed concrete filled columns. These type of columns can be used for structures like airports, schools, and stadiums; taking the advantage of exposed steel for aesthetic purpose and high fire resistance. It can also be used for high rise structures; taking advantage of high fire resistance and reduction in self-weight of a structure.

Effects of temperature on acceleration and simulation of indoor corrosion test of Q235 carbon steel

Purpose The purpose of this paper is to study the influence of temperature on the acceleration and simulation of indoor corrosion tests and the corrosion behavior of Q235 carbon steel. Design/methodology/approach The indoor corrosion test was carried out by continuous salt spray in a salt spray chamber. Weight loss analysis, X-ray diffraction, cannon 1500 D, scanning electron microscopy and electrochemical techniques are used to analyze the results. Findings It was found that thickness loss of Q235 carbon steel increases with higher temperature and it can reach 0.095 mm at 50°C. Compared with the Xisha exposure test, the acceleration rate can achieve 230 times. This phenomenon indicates that decreasing the experimental temperature is beneficial to the anti-corrosion of the Q235 carbon steel. It is fascinating to find that acceleration and simulation increase with temperature simultaneously, which shows that β-FeOOH promotes the corrosion rate and α-FeOOH provides high simulation. Meanwhile, electrochemical impedance spectroscopy indicates that the resistance of the rust layer improves with temperature. Practical implications Through the study, the authors found that with the increase of temperature, the acceleration and simulation of indoor corrosion test improved, corrosion products and kinetics are the same as those in outdoor exposure test, and which means that the laboratory can achieve the long-term corrosion degree of outdoor exposure in a short time, and the similarity with outdoor exposure is high. This helps to the study of marine atmospheric corrosion, and indoor accelerated corrosion tests can largely eliminate regional differences by adjusting some environmental factors, and lay a foundation for marine atmospheric corrosion. Originality/value The effects of temperature on the acceleration and simulation of indoor corrosion tests are discussed. Through laboratory experiments, the long-term service life of Q235 carbon in the Xisha marine atmosphere can be predicted effectively.

A Novel Perspective for Examining and Comparing Real and Virtual Test Tasks Performed by the Dominant and Non-Dominant Hand in Healthy Adults

This study presents a novel perspective for the study of functional lateralization in a virtual reality environment. In the model study of handedness, the recognition of the dominant and non-dominant hand in real and virtual conditions was assessed using selected tests, such as a real light exposure test of Piórkowski’s apparatus and classical clinical tests, as well as virtual test tasks, in healthy adults. Statistically significant differences between the dominant and non-dominant hand were observed for tests carried out both in classical conditions and the virtual environment. The results and findings of other studies suggest that the virtual reality approach is a very promising and sensitive tool in the research on functional asymmetries in healthy and disease for motor skills and cognition processes.

Ibogaine Blocks Cue- and Drug-Induced Reinstatement of Conditioned Place Preference to Ethanol in Male Mice

Ibogaine is a psychedelic extracted from the plant Tabernanthe iboga Baill. (Apocynaceae), natural from Africa, and has been proposed as a potential treatment for substance use disorders. In animal models, ibogaine reduces ethanol self-administration. However, no study to date has investigated the effects of ibogaine on ethanol-induced conditioned place preference (CPP). The present study aimed to investigate the effects of repeated treatment with ibogaine on the reinstatement of CPP to ethanol in male mice. The rewarding effects of ethanol (1.8 g/kg, i. p.) or ibogaine (10 or 30 mg/kg, p. o.) were investigated using the CPP model. Furthermore, we evaluated the effects of repeated treatment with ibogaine (10 or 30 mg/kg, p. o.) on the reinstatement of ethanol-induced CPP. Reinstatement was evaluated under two conditions: 1) during a priming injection re-exposure test in which animals received a priming injection of ethanol and had free access to the CPP apparatus; 2) during a drug-free test conducted 24 h after a context-paired re-exposure, in which subjects received an injection of ethanol and were confined to the compartment previously conditioned to ethanol. Our results show that ethanol, but not ibogaine, induced CPP in mice. Treatment with ibogaine after conditioning with ethanol blocked the reinstatement of ethanol-induced CPP, both during a drug priming reinstatement test and during a drug-free test conducted after re-exposure to ethanol in the ethanol-paired compartment. Our findings add to the literature suggesting that psychedelics, in particular ibogaine, may have therapeutic properties for the treatment of alcohol use disorder at doses that do not have rewarding effects per se.

Pengaruh Paparan Chlorine terhadap Stress Fisiologis dan Ekspresi Gen Hsp70 dan Hsp90 pada Abalon (Haliotis squamata)

Abalon merupakan salah satu moluska bercangkang tunggal yang memiliki nilai ekonomis tinggi dan merupakan komoditas potensial dalam peningkatan devisa Negara. Namun permasalahannya adalah mudahnya abalone mengalami stress akibat perubahan berbagai faktor lingkungan seperti suhu, salinitas, bakteri Vibrio dan bahan desinfektan seperti chlorine. Penelitian ini dilakukan untuk mengetahui tingkat stress benih abalone terhadap paparan chlorine pada gen heat shock protein (HSP) dan mengetahui perubahan enzim-enzim antioksidan seperti SOD,CAT,PO dan perubahan struktur histologi otot kaki abalone akibat paparan chlorine. Koleksi benih abalone dengan ukuran cangkang 3-4 cm dari unit hatchery abalone, BPIU2K Karangasem Bali. Uji paparan abalone pada akuarium kaca volume 100 L dengan konsentrasi chlorine 10 ppm. Pengambilan sample (hemolim, otot kaki, gonad) dilakukan pada waktu pengamatan (0,12,24,48 jam). Pengamatan meliputi uji ekspresi gen heat shock protein (Hsp70 dan Hsp90), aktifitas enzim-enzim antioksidan dan histology pada otot kaki. Hasil penelitian menunjukkan bahwa Hsp70 terekspresi paling tinggi pada hemolim abalone yaitu sebesar 350 kali lipat pada paparan jam ke 12 dibandingkan kontrol (P<0.05). Sedangkan, Hsp90 pada waktu yang sama menunjukkan tingkat stress abalone paling tinggi pada otot kaki dengan tingkat ekspresi sebesar 7 kali lipat jika dibandingkan kontrol (P<0.05). Gen heat shock protein diekspresikan cukup tinggi pada uji paparan chlorine, namun demikian Hsp70 menunjukkan tingkat ekspresi yang lebih tinggi jika dibanding dengan Hsp90. Hsp70 lebih sensitif sebagai marka stress abalone akibat paparan chlorine. Perubahan struktur histologi menunjukkan cemaran chlorine dapat meningkatkan ukuran diameter hemolim sinus dan kerusakan pada lapisan epithel otot kaki abalone. Abalone is one of the single-shelled mollusks which has high economic value and is a commodity in increasing the country's foreign exchange. However, the problem is that it is easy for abalone to experience stress due to the influence of various environmental factors such as temperature, salinity, Vibrio bacteria and disinfectants such as chlorine. The study was conducted to determine the stress level of abalone seeds produced by hatcheries against residual chlorine. The aim of the study were to see the stress level based on the heat shock protein (HSP) gene and to see changes in antioxidant enzymes such as SOD, CAT, PO and histological structure of abalone foot muscles due to chlorine contamination. Collection of abalone seeds with a 3-4 cm shell size from the abalone hatchery unit, BPIU2K Karangasem Bali. Abalone exposure test using a glass volume of 100 L with a chlorine concentration of 10 ppm. Furthermore, sampling was carried out (hemolime, leg muscles, gonads) at the time of observation (0.12,24,48 hours). Observations included heat shock protein gene expression (Hsp70 and Hsp90) and histology in foot muscles. The results showed that Hsp70 was the highest expressed in hemolime abalone 350 times at 12 hours exposure compared to controls (P <0.05). Meanwhile, Hsp90 at the same time showed the highest level of stress on leg muscles with an expression level of 7 times when compared to controls (P <0.05). It was concluded that the heat shock protein gene was expressed high enough in the chlorine exposure test, however, Hsp70 was more sensitive as a sign of abalone stress as indicated by a higher expression level when compared to Hsp90. Changes in the histological structure show that chlorine contamination can increase the diameter of the sinus hemolime and damage to the epithelial layer of the abalone foot muscles.