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Kiwi Omnicup versus Malmstrom metal cup in vacuum assisted delivery: a randomized comparative trial

Ismail NA, Saharan WS, Zaleha MA, Jaafar R, Muhammad JA, Razi ZR

J Obstet Gynaecol Res, 2008 Jun;34(3):350-3.
PMID: 18686348

AIM: To compare the success, clinical outcomes, and maternal and neonatal complications between the Kiwi Omnicup and the Malmstrom metal cup in vacuum assisted delivery.
METHODS: This was a prospective randomized comparative trial. Women who required vacuum assisted vaginal delivery were randomized into the Kiwi Omnicup (KO) group and the Malmstrom metal cup (MM) group. The vacuum assisted deliveries were conducted according to hospital protocol. Details of the procedure and delivery outcomes including success and complications were analyzed.
RESULTS: One hundred and sixty-four women were recruited - 85 were assigned to vacuum assisted delivery using the KO and 79 the MM. One hundred percent delivery success was achieved with no significant differences between the two instruments in terms of maternal morbidity (P = 0.66). Six women in the MM group sustained post delivery complications in comparison to five in the KO group. Three babies were diagnosed with birth asphyxia in each group. More babies in the MM group were admitted to the Neonatal Intensive Care Unit (NICU) (10 babies versus 5 babies) and suffered complications (14 versus 12 babies), compared to the KO group, although the difference was not statistically significant. There were no intrapartum or neonatal deaths and of those admitted to the NICU, all were discharged within a week without any serious consequences.
CONCLUSION: Kiwi Omnicup is an effective alternative to the currently available Malmstrom metal cup for vacuum assisted delivery with no increase in maternal or neonatal morbidity or mortality.

Matched MeSH terms: Vacuum Extraction, Obstetrical/adverse effects; Vacuum Extraction, Obstetrical/instrumentation*
Fulltext Neonatal posterior fossa haemorrhage associated with vacuum extractor

Ghani AR, Prakash RG, Abdullah J

Med J Malaysia, 2006 Mar;61(1):100-2.
PMID: 16708744 MyJurnal

We report one case of posterior fossa intracranial haemorrhage in a full-term Malay baby boy following vacuum assisted delivery. The patient, a term baby boy was delivered by a vacuum extraction and later developed signs of increased intracranial pressure 72 hours after birth. Computed tomography (CT) of the brain showed a posterior fossa intracranial haemorrhage with acute obstructive hydrocephalus. He was initially treated with isolated ventricular shunting which later caused an upward cerebellar herniation. An immediate suboccipital craniectomy for evacuation of cerebellar haematoma was performed which resulted in a gradual recovery.

Matched MeSH terms: Vacuum Extraction, Obstetrical/adverse effects*; Vacuum Extraction, Obstetrical/instrumentation
Attenuation of excitation decay rate due to collective effect

Tay BA

Phys Rev E Stat Nonlin Soft Matter Phys, 2014 Aug;90(2):022142.
PMID: 25215723

We study a series of N oscillators, each coupled to its nearest neighbors, and linearly to a phonon field through the oscillator's number operator. We show that the Hamiltonian of a pair of adjacent oscillators, or a dimer, within the series of oscillators can be transformed into a form in which they are collectively coupled to the phonon field as a composite unit. In the weak coupling and rotating-wave approximation, the system behaves effectively as the trilinear boson model in the one excitation subspace of the dimer subsystem. The reduced dynamics of the one excitation subspace of the dimer subsystem coupled weakly to a phonon bath is similar to that of a two-level system, with a metastable state against the vacuum. The decay constant of the subsystem is proportional to the dephasing rate of the individual oscillator in a phonon bath, attenuated by a factor that depends on site asymmetry, intersite coupling, and the resonance frequency between the transformed oscillator modes, or excitons. As a result of the collective effect, the excitation relaxation lifetime is prolonged over the dephasing lifetime of an individual oscillator coupled to the same bath.

Matched MeSH terms: Vacuum
Physico-chemical changes occurring in oil when atmospheric frying is combined with post-frying vacuum application

Ahmad Tarmizi AH, Niranjan K, Gordon M

Food Chem, 2013 Jan 15;136(2):902-8.
PMID: 23122143 DOI: 10.1016/j.foodchem.2012.08.001

The aim of this study was to investigate the effect of atmospheric frying followed by drainage under vacuum on the stability of oil, compared to similar frying with drainage at atmospheric pressure. Changes in the oil were assessed by the free fatty acid (FFA) content, p-anisidine value (AnV), colour, viscosity, fatty acid profile and concentration of tocols. The rate of FFA formation in the case of vacuum drainage was found to be about half that of atmospheric drainage. Oil deterioration by oxidation and polymerisation was also reduced by the use of vacuum drainage. The AnV of the oil after vacuum drainage was lower by about 12%, the total colour difference was improved by 14% and viscosity was slightly reduced after 5 days of frying, compared to the values for oil that had been drained at atmospheric pressure. There was a reduction in the loss of polyunsaturated fatty acids in the case of vacuum drainage after 5 days of frying but differences in retention of tocols were only evident in the first two days of frying.

Matched MeSH terms: Vacuum
Fulltext An acceleration of microwave-assisted transesterification of palm oil-based methyl ester into trimethylolpropane ester

Aziz NAM, Yunus R, Hamid HA, Ghassan AAK, Omar R, Rashid U, et al.

Sci Rep, 2020 11 12;10(1):19652.
PMID: 33184363 DOI: 10.1038/s41598-020-76775-y

Microwave-assisted synthesis is known to accelerate the transesterification process and address the issues associated with the conventional thermal process, such as the processing time and the energy input requirement. Herein, the effect of microwave irradiation on the transesterification of palm oil methyl ester (PME) with trimethylolpropane (TMP) was evaluated. The reaction system was investigated through five process parameters, which were reaction temperature, catalyst, time, molar ratio of TMP to PME and vacuum pressure. The yield of TMP triester at 66.9 wt.% and undesirable fatty soap at 17.4% were obtained at 130 °C, 10 mbar, sodium methoxide solution at 0.6 wt.%, 10 min reaction time and molar ratio of TMP to PME at 1:4. The transesterification of palm oil-based methyl ester to trimethylolpropane ester was 3.1 folds faster in the presence of microwave irradiation. The total energy requirement was markedly reduced as compared to the conventional heating method. The findings indicate that microwave-assisted transesterification could probably be an answer to the quest for a cheaper biodegradable biolubricant.

Matched MeSH terms: Vacuum
Fulltext Antioxidant Activity, and Volatile and Phytosterol Contents of Strobilanthes crispus Dehydrated Using Conventional and Vacuum Microwave Drying Methods

Chua LYW, Chua BL, Figiel A, Chong CH, Wojdyło A, Szumny A, et al.

Molecules, 2019 04 09;24(7).
PMID: 30970652 DOI: 10.3390/molecules24071397

The preservation of active constituents in fresh herbs is affected by drying methods. An effective drying method for Strobilanthes crispus which is increasingly marketed as an important herbal tea remains to be reported. This study evaluated the effects of conventional and new drying technologies, namely vacuum microwave drying methods, on the antioxidant activity and yield of essential oil volatiles and phytosterols. These drying methods included convective drying (CD) at 40 °C, 50 °C, and 60 °C; vacuum microwave drying (VMD) at 6, 9, and 12 W/g; convective pre-drying and vacuum microwave finish drying (CPD-VMFD) at 50 °C and 9 W/g; and freeze-drying (FD). GC–MS revealed 33 volatiles, and 2-hexen-1-ol, 2-hexenal, 1-octen-3-ol, linalool, and benzaldehyde were major constituents. The compounds β-sitosterol and α-linolenic acid were the most abundant phytosterol and fatty acid, respectively, in fresh S. crispus. The highest phenolic content was achieved with CD at 60 °C. The highest antioxidant activity was obtained with CD at 40 °C and VMD at 9 W/g. On the contrary, the highest total volatiles and phytosterols were detected with CD at 50 °C and VMD at 9 W/g, respectively. This study showed that CD and VMD were effective in producing highly bioactive S. crispus. A suitable drying parameter level, irrespective of the drying method used, was an important influencing factor.

Matched MeSH terms: Vacuum
Processing of coconut sap into sugar syrup using rotary evaporation, microwave, and open-heat evaporation techniques

Asghar MT, Yusof YA, Mokhtar MN, Yaacob ME, Ghazali HM, Varith J, et al.

J Sci Food Agric, 2020 Aug;100(10):4012-4019.
PMID: 32337729 DOI: 10.1002/jsfa.10446

BACKGROUND: Coconut sugar has a caramel color with a taste like brown sugar. It is commonly used as natural sweetener. However, coconut sugar has been produced from coconut sap using a traditional method that involves heating the sap at high temperature (>100 °C) in an open pan for a long period (3-5 h). This conventional method results in an over-cooked sugar, which leads to quality deterioration in terms of both its physical and chemical properties. The current study aimed to investigate the processing of coconut sap into sugar syrup using alternative processing techniques such as rotary vacuum evaporation (RE) and microwave evaporation (ME), comparing them with open-heat evaporation (OHE) technique.
RESULTS: Coconut sugar syrup produced by rotary evaporation at 60 °C and 250 mbar vacuum (RE-60) required the shortest production time (12.2 min) and the lowest processing temperature (54.8 °C) when compared with ME (13 min and 103.2 °C) and OHE (46.8 min and 101.6 °C). It also had a light brownish color with a higher L* value (35.17) than the ME (29.84) and OHE (23.84) methods. It was found to contain higher amounts of monosaccharides (fructose and glucose) and lower amounts of disaccharides (sucrose). Furthermore, the amount of energy required for RE-60 (0.35 kWh) was much less than for OHE (0.83 kWh).
CONCLUSION: This study provided an alternative processing method for the sugar processing industry to produce coconut sugar using the rotary evaporation method at 60 °C under 250 mbar vacuum with better physicochemical qualities, shorter processing time, and minimum input energy. © 2020 Society of Chemical Industry.

Matched MeSH terms: Vacuum
Fulltext The Effect of Stacking Sequence and Ply Orientation on the Mechanical Properties of Pineapple Leaf Fibre (PALF)/Carbon Hybrid Laminate Composites

Hashim MKR, Abdul Majid MS, Jamir MRM, Kasim FH, Sultan MTH

Polymers (Basel), 2021 Jan 31;13(3).
PMID: 33572609 DOI: 10.3390/polym13030455

In this paper, the effects of stacking sequence and ply orientation on the mechanical properties of pineapple leaf fibre (PALF)/carbon hybrid laminate composites were investigated. The hybrid laminates were fabricated using a vacuum infusion technique in which the stacking sequences and ply orientations were varied, which were divided into the categories of cross-ply symmetric, angle-ply symmetric, and symmetric quasi-isotropic. The results of tensile and flexural tests showed that the laminate with interior carbon plies and ply orientation [0°, 90°] exhibited the highest tensile strength (187.67 MPa) and modulus (5.23 GPa). However, the highest flexural strength (289.46 MPa) and modulus (4.82 GPa) were recorded for the laminate with exterior carbon plies and the same ply orientation. The fracture behaviour of the laminates was determined by using scanning electron microscopy, and the results showed that failure usually initiated at the weakest PALF layer. The failure modes included fibre pull-out, fibre breaking, matrix crack, debonding, and delamination.

Matched MeSH terms: Vacuum
Fulltext PARTICULATE RESUSPENSION DURING THE USE OF VACUUM CLEANERS ON OFFICE CARPETS IN UNIVERSITI MALAYSIA TERENGGANU

SYAFIQAH ASYIQIN ROHADI, IZAN JAAFAR, ISMANIZA ISMAIL, TENGKU AZMINA IBRAHIM

UMT Journal of Undergraduate Research, 2020;2(2):41-48.
MyJurnal

The household activities such as vacuuming may elevate the concentration of particulate matter in indoor environments. Cleaning workers and occupants inside closed room may be exposed to the fine particulate matter and at risk of developing numerous respiratory symptoms. This study aims to determine the concentration of the particulate matter (PM10 and PM2.5) that might arise during vacuuming activities and estimated the surface compartmental residence time of particulate matter in indoor environment after each vacuuming activities. The PM10 and PM2.5 concentrations throughout vacuuming were measured in forty-seven offices in Universiti Malaysia Terengganu using the TSI Dust Track DRX. Based on the concentrations measured, the surface compartmental residence time was then estimated using standardized equations taken from literature. The result shows that highest particulate matter concentration was nearly eleven times higher than the World Health Organization guidelines of 25 µg/m3 for PM2.5 concentration (PM2.5 was 270 µg/m3, PM10 was 421 µg/m3), while the particulate matter were estimated to remain lingers inside the air for around 1-4 days before being deposited on the surface. In conclusion, the usage of vacuum cleaners may contribute to more particulate matter being released inside the air due to the resuspension phenomenon. Therefore, it is important for the occupants to maintain proper ventilation after each vacuuming activities took place.

Matched MeSH terms: Vacuum
Fulltext Effect of modified atmosphere packaging on microbial flora changes in fishery products

Velu, S., Abu Bakar, F., Mahyudin, N.A., Saari, N., Zaman, M.Z.

International Food Research Journal, 2013;20(1):17-26.
MyJurnal

Modified atmosphere packaging (MAP) has become a popular method for packaging foods as it can extend the shelf life of food with minimal quality defect. Oxygen, nitrogen and carbon dioxide are the common gases used in MAP, Oxygen and carbon dioxide inclusive as only these two gaseous have the preservative effects on the packed food product. Their effect on microbial changes of any food product throughout storage period is highly depend on type of the product and packaging materials, appropriate gas composition, storage temperature, the ratio between gas and product volume, and hygienic manner during processing and packaging. MAP with highest percentage of carbon dioxide is proven to be more effective than vacuum packaging in inhibiting the growth of spoilage and pathogenic bacteria in many fishery products. This article reviews the consequences of MAP towards microbial changes in fishery products.

Matched MeSH terms: Vacuum
Fulltext Physico-chemical changes in dabai (Canarium odontophyllum Miq.) fruit during modified atmosphere storage

Ding, P., Diana, J.

International Food Research Journal, 2013;20(6):3033-3040.
MyJurnal

Dabai or Canarium odontophyllum Miq., from the family Burseraceae, is an important indigenous fruit to Borneo Island. However, it is a highly perishable fruit with short shelf life. Postharvest technology such as modified atmosphere packaging (MAP) can be used to maintain highly perishable fresh fruit quality and increase its shelf life. There is not much work has been carried out to study effect of MAP on dabai fruit. Therefore, this study was conducted to determine the effect of four different types packaging methods on the postharvest quality of dabai fruits. Total of 240 fruit were used for each replication and the experiment was repeated thrice. Fruit were divided equally into four groups with each group packed in low-density polyethylene plastic bag, low-density polyethylene plastic bags lined with tissue paper, low-density polyethylene plastic bag with vacuumed and control (unwrapped). The fruit were then stored in a cold room of 10°C for 8 days. The fruits were analyzed for peel and flesh colour (L*, C* and hue angle), CO2 and C2H4 production, weight loss, firmness, soluble solids concentration (SSC), titratable acidity (TA) and pH at every two days interval. Data were analyzed using analysis of variance and means was separated using Duncan’s multiple range tests. The use of MAP retained peel colour (L*, C* and hue angle values), flesh colour (L*values), SSC and TA of dabai fruit. The CO2 production in MAP fruit was significant lower than control. Although vacuum packed showed lowest weight loss, flesh discolouration, soggy texture and foul sour odour developed during 8 days of storage. Neither packing dabai fruit in low-density polyethylene plastic bag nor bag lined with tissue paper retained better fruit quality. Thus, it is recommended packing dabai fruit in low-density polyethylene plastic bag is sufficient to retain fruit quality during 8 days of storage at 10oC.

Matched MeSH terms: Vacuum
Fulltext Effects of different levels of CO2 on biochemical changes and relationships among different quality indices in Indian mackerel (Rastrelliger kanagurta)

Chong, C.Y., Fatimah, A.B., Russly, A.R., Jamilah, B., Selvi, V., Maryam, S.

International Food Research Journal, 2013;20(1):383-389.
MyJurnal

The profile of total volatile base nitrogen (TVBN), pH, biogenic amines were studied in Indian mackerel packed under different levels of CO2. Gutted and beheaded Indian mackerel was stored in air, vacuum packaging (VP), 30% CO2/65% N2/5% O2 (M30C), 60% CO2/35%N2/5%O2 (M60C), 80% CO2/15%N2/5% O2 (M80C) and 100% CO2 (M100C) at 5°C for 12 days. The application of VP and MAP was effective in retarding the formation of TVBN, total biogenic amines and improve the shelf life of Indian mackerel. Cadaverine obtained the best correlation with storage time when compared with other biogenic amines. Cadaverine or cadaverine + putrescine can serve as a reliable objective freshness indicator of fish stored in different atmospheres. Among the commonly used freshness indices, TVBN was the best quality indicator correlated with histamine. VP and MAP conditions influenced the performance of quality indicators. pH was a good quality indicator of spoilage in air-stored fish except for VP and MAP packed fish. Lower value of TVBN (30 mg/100g) was suggested as an upper limit for this species of fish under MAP condition based on APC and sensory result.

Matched MeSH terms: Vacuum
Fulltext Effects of drying, fermented and unfermented tea of Ocimum tenuiflorum Linn. on the antioxidant capacity

Rabeta, M.S., Lai, S.Y.

International Food Research Journal, 2013;20(4):1601-1608.
MyJurnal

Antioxidant capacity of Ocimum tenuiflorum L. or ‘ruku’ were determined in this study. Fresh
leaves of Ocimum tenuiflorum was subjected to freeze drying, vacuum drying and processed
into fermented and unfermented tea. The samples were extracted using distilled water and the
total phenolics, total flavonoids, condensed tannin content, anthocyanins and total antioxidant
capacity (TAC) were assessed, measured with ferric reducing antioxidant power (FRAP)
and 1,1-diphenyl-1-picrylhydrazyl radical scavenging capacity (DPPH) assays. The results
showed that drying the fresh leaves of Ocimum tenuiflorum and processing them into tea leaves
significantly increase (P < 0.05) the antioxidant capacity, total phenolic content, total flavonoid
content, and condensed tannin content. However, anthocyanins content showed reduction
after drying. In the present study, it can be concluded that the vacuum drying method seem
to produce a product with higher quality of antioxidant properties than freeze drying. Hence,
vacuum drying can be used to replace freeze drying as it is also cheaper than freeze drying.

Matched MeSH terms: Vacuum
Fulltext Modified vacuum-assisted closure

Sia, S.F., Fong, E.P.

JUMMEC, 2006;9(2):24-27.
MyJurnal

The treatment of large ulcers is a problem. Closure with flaps and even skin grafts in compromised patients is often fraught with risks. Dressing these large wounds is also a problem, as they are often heavily exudative. We report our experience using the vacuum-assisted closure technique in managing difficult ulcers in four patients. A modification of the technique using cheap, easily available materials is described. The vacuum-assisted suction is an effective treatment for large ulcers in compromised patients. It facilitates considerable contraction of the wound, and in smaller wounds; the vacuum-assisted closure allows sufficient contracture to enable delayed primary closure. We recommend the use of this method of wound dressing and closure in large wounds particularly, in high-risk patients where extensive flap coverage or even split skin graft would incur considerable risk.

Matched MeSH terms: Vacuum
Fulltext Mechanical behaviour and microstructure Aluminium Foam Tube Produce (AFTP) using infiltration method with vacuum-gas

Ismail Lias, Muhammad Hussain Ismail, Iskandar Dzulkernain Md Raffee, Mohd Aman Ihsan Mamat

Pertanika Journal of Science & Technology, 2017;25(103):223-232.
MyJurnal

Aluminium foam tube is a metal that consists of porous medium with special characteristics such as good energy absorption, good heat transfer and high thermal conductivity. These make it suitable to be used in a wide range of applications such as in heat exchangers. The aim of this project is to identify and analyse mechanical behaviour and microstructure aluminium foam tube produced and fabricated with infiltration method with vacuum-gas. The density of aluminium foam tube was also determined and an average aluminium foam tube with porosity 50% - 80% with the average NaCl particle size 2mm, 3mm and 4mm was produced. Foams with porosity 60%-75% NaCl has higher energy absorption. These was based on foam structure, density and maximum compressive load test result.

Matched MeSH terms: Vacuum
Partial hydrogenation induced interaction in a graphene-SiO2 interface: irreversible modulation of device characteristics

Iwasaki T, Muruganathan M, Schmidt ME, Mizuta H

Nanoscale, 2017 Jan 26;9(4):1662-1669.
PMID: 28074959 DOI: 10.1039/c6nr08117g

The transformation of systematic vacuum and hydrogen annealing effects in graphene devices on the SiO2 surface is reported based on experimental and van der Waals interaction corrected density functional theory (DFT) simulation results. Vacuum annealing removes p-type dopants and reduces charged impurity scattering in graphene. Moreover, it induces n-type doping into graphene, leading to the improvement of the electron mobility and conductivity in the electron transport regime, which are reversed by exposing to atmospheric environment. On the other hand, annealing in hydrogen/argon gas results in smaller n-type doping along with a decrease in the overall conductivity and carrier mobility. This degradation of the conductivity is irreversible even the graphene devices are exposed to ambience. This was clarified by DFT simulations: initially, silicon dangling bonds were partially terminated by hydrogen, subsequently, the remaining dangling bonds became active and the distance between the graphene and SiO2 surface decreased. Moreover, both annealing methods affect the graphene channel including the vicinity of the metal contacts, which plays an important role in asymmetric carrier transport.

Matched MeSH terms: Vacuum
Fabrication of amorphous silicon microgap structure for energy saving devices

Dhahi T, Hashim U, Ali M, Nazwa T

Sains Malaysiana, 2012;41:755-759.

We report here the fabrication of microgaps electrodes on amorphous silicon using low cost techniques such as vacuum deposition and conventional lithography. Amorphous silicon is a low cost material and has desirable properties for semiconductor applications. Microgap electrodes have important applications in power saving devices, electrochemical sensors and dielectric detections of biomolecules. Physical characterization by scanning electron microscopy (SEM) demonstrated such microgap electrodes could be produced with high reproducibility and precision. Preliminary electrical
characterizations showed such structures are able to maintain a good capacitance parameters and constant current supply over a wide ranging differences in voltages. They have also good efficiency of power consumption with high insulation properties.

Matched MeSH terms: Vacuum
Fulltext Characterization data of titanate compounds synthesized using hydrothermal method at various temperature

Razali MH, Ismail NA, Osman UM, Rozaini MZH, Yusoff M

Data Brief, 2020 Feb;28:104992.
PMID: 31890823 DOI: 10.1016/j.dib.2019.104992

Titanate compounds was synthesized using hydrothermal method at various temperature (100, 150, 200, and 250 °C) for 24 hours. As-synthesized titanate was characterized using FTIR, XRD and nitrogen gas adsorption. FTIR spectra was scanned from 4000 to 400 cm-1 using Perkin Elmer Spectrum 100 FTIR spectrophotometer. XRD diffractogram was performed by using Rigaku Miniflex (II) X-ray diffractometer operating at a scanning rate of 2.00° min-1. The diffraction spectra were recorded at the diffraction angle, 2θ from 10° to 80° at room temperature. Nitrogen gas adsorption analysis was studied by using Micromeritics ASAP2020 (Alaska) to determine the surface area and pores size distribution. The nitrogen adsorption and desorption was measured at 77 K (temperature of liquid nitrogen) and the samples were degassed in a vacuum at 110 °C under nitrogen flow for overnight prior to analysis.

Matched MeSH terms: Vacuum
Fulltext Determination of the Major Component of Water Fraction of Katuk (Sauropus androgynous (L.) Merr.) Leaves by Liquid Chromatography-Mass Spectrometry

Mustarichie R, Salsabila T, Iskandar Y

J Pharm Bioallied Sci, 2019 Dec;11(Suppl 4):S611-S618.
PMID: 32148372 DOI: 10.4103/jpbs.JPBS_205_19

Background: The katuk leaf (Sauropus androgynous (L.) Merr.) is one of the plants that are used to overcome baldness by the people of Kampung Mak Kemas, Malaysia. It is suspected that secondary metabolites contained in katuk leaves play a key role in stimulating hair growth.
Aims and Objectives: The aim of this study was to identify the optimum method to obtain one of the chemical compounds in the water fraction and to identify the hypothesized chemical isolates in the water fraction katuk leave's ethanol extract.
Materials and Methods: The methods used in this study included the collection and determination of the katuk plant, the processing of the katuk, phytochemical filtrating, extracting with ethanol 96%, and fractionation using the liquid-liquid extraction method with n-hexane, ethyl acetate, and water solvents The water fraction of katuk leaves was analyzed by its components by thin-layer chromatography using the stationary phase of silica gel 60 F254, developer of n-butanol:acetic acid:water (4:1:5), and detection under ultraviolet (UV) light at a wavelength of 366 and 254nm, as well as with vanillin-sulfuric acid reagent. To isolate the compounds from water fraction of katuk leaves, it was then eluted with a vacuum column chromatography by eluent with a level polarity that would get 11 subfractions. Each subfraction was checked by two-dimensional thin-layer chromatography to see subfraction purity characterized by the appearance of a spot on the chromatogram plate. The isolate was analyzed using spot test, ultraviolet-visible spectrophotometer, infrared spectrophotometer, and liquid chromatography-mass spectrometry.
Results: The isolate was an alkaloid compound with a molecular mass of 406.3131 m/z with the molecular formula C21H39N6O2 as S, S-5, 5'-amino-4,4'-dihexyl-propyldihydropyrazol-3, 3-one.
Conclusion: One of the chemical compounds contained in the water fraction of the ethanol extract of the katuk leaf was an alkaloid group.

Matched MeSH terms: Vacuum
Effects of debinding and sintering atmosphere on properties and corrosion resistance of powder injection molded 316 L - stainless steel

Raza MR, Sherazi I, Muhammad Aslam, Ahmad F, Abu Bakar Sulong, Muhamad Norhamidi, et al.

Sains Malaysiana, 2017;46:285-293.

316L stainless steel is a common biomedical material. Currently, biomedical parts are produced through powder injection molding (PIM). Carbon control is the most critical in PIM. Improper debinding can significantly change the properties of the final product. In this work, thermal debinding and sintering were performed in two different furnaces (i.e. laboratory and commercially available furnaces) to study the mechanical properties and corrosion resistance. Debounded samples were sintered in different atmospheres. The samples sintered in inert gas showed enhanced mechanical properties compared with wrought 316L stainless steel and higher corrosion rate than those sintered in the vacuum furnace. The densification and tensile strength of the hydrogen sintered samples increased up to 3% and 51%, respectively, compared with those of the vacuum-sintered samples. However, the samples sintered in inert gas also exhibited reduced ductility and corrosion resistance. This finding is attributed to the presence of residual carbon in debonded samples during debinding.

Matched MeSH terms: Vacuum

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