Spatial Distribution of Dissolved Inorganic Nutrients and Phytoplankton around Kota Kinabalu Wetland, Sabah, Malaysia

Kota Kinabalu Wetland is importantly habited of mangrove, diverse aquatic flora and fauna as well as feeding stop for migratory birds. This wetland is inundated with the tidal flow, as connected with a small river and nearby coastal areas, thus. A study was carried out to determine the spatial distribution of dissolved inorganic nutrients and phytoplankton diversity at Kota Kinabalu (KK) Wetlands. Five stations, in which river mouth of Likas Bay, river channel (two stations) and inundated area (two stations) in KK Wetland were selected for this study. In-situ parameters of water, water for nutrients and phytoplankton samples were collected from May 2019 until October 2019. The highest concentration of nitrate (0.115 mg/L) was recorded at inundated area of wetland (S5) while the lowest nitrate concentration (0.0047 mg/L) was found at river (S3) flowing towards wetland. The concentrations of ammonia (0.2004 to 2.311 mg/L) were recorded relatively higher at every station compared to other dissolved inorganic nutrients (DIN). The concentration of phosphate was determined in the ranges of 0.0089 - 0.0513 mg/L. Nitrate, ammonia and phosphate showed no significant difference (P = 0.737) in terms of DIN concentration at all five sampling stations during the study period. Twenty-four genera of phytoplankton were identified, dominated by diatoms (55.29%), followed by dinoflagellates (24.95%), Chrysophyta (11.15%), Spirotrichea (5.28%) and Cyanophyta (3.33%). Dominating species throughout the study period include Chaetoceros sp., Pseduo-nitzschia sp., and Cylindrotheca closterium, Peridinium quinquecorne and Alexandrium sp. Phytoplankton species compositions were observed the highest in river mouth area in July with the highest density of 12.115 × 104 cells/mL. The study showed that nutrient concentration was insignificant (P = 0.614) in altering the phytoplankton density, as influences with the tidal water.

Distribution Pattern of Dissolved Inorganic Nutrients and Phytoplankton Diversity in River Estuary, Kota Kinabalu Sabah, Malaysia

Nutrients are influenced by anthropogenic activities and consequently change the diversity and density of phytoplankton. The spatial distribution of dissolved inorganic nutrients and phytoplankton diversity and density were determined in river estuary, Kota Kinabalu, Sabah, Malaysia. Samples of water and phytoplankton were collected from six locations of river estuary during the month of May 2019 to October 2019. The highest abundances of 86% diatoms were determined during the study period. This was followed by 13% and 1% of dinoflagellates and Cyanobacteria respectively. The most dominance species of Skeletonema costatum, with density of 1186.69 × 103 cells/L and Thalassiosira sp. (938.01 ×103 cells/L) were recorded from Station 1 (upstream) and Station 5 (mangrove area) respectively. The Chaetoceros sp. (84.25 × 103 cells/L) was the dominated in Station 6 (control site). Station 4 (residential area) accounted the highest diversity of species such as Skeletonema costatum, Thalassiosira sp., Peridinium sp., Gonyaulax sp., and Cylindrotheca sp. with total cell density of 142.98 × 103 cells/L. The high diversity index of 5.2 to 7.09 and evenness index of 1.81 to 2.87 were determined from this river estuary. Very poor relationship was observed with the cell density and dissolved inorganic nutrients, phosphate (R2 = 0.2437), ammonium (R2 = 0.301) and nitrate (R2 = 0.406). The diversity and abundance of phytoplankton in this river estuary not only depend on nutrients, but might be associated with other environmental factors, tidal fluctuations and rate of discharge of nutrient inputs from surrounding areas. This study suggests that long term monitoring not only the nutrients, but discharges and flushing of nutrient during rainfall and tidal fluctuation together with environmental factors should be considered in order to conclude status on the diversity and abundance of phytoplankton in river estuary.

Heavy metal pollution assessment in marine sediments in the Northwest coast of Sabah,Malaysia

Heavy metal contents along the Northwest coast of Sabah were determined to interpret the pollution level in the marine sediment. The metal abundance is regulated by the physico-chemical properties such as the average sediment pH(7.82, 9.00 and 8.99), organic matter(0.62%, 1.60%, and 2.27%), moisture content(25.00%, 29.70%, and 15.00%) and sandy texture in Kota Belud, Kudat and Mantanani Island,respectively. The major elements show Ca>Fe>Mg>Al>Mn for all study sites, while the heavy metals show Ni>Cr>Zn>Cu>Co>Pb, Cr>Ni>Zn>Cu>Pb>Co and Zn>Pb>Cr>Ni, for Kota Belud, Kudat and Mantanani Island, respectively. The pollution degree of heavy metals was evaluated by using the Sediment Quality Assessment(SQA). The SQA parameters indicated none to moderate pollution in Kota Belud that shows Class 0, Class 1 and Class 2 pollution. The parameters also indicated none to low pollution in Kudat and Mantanani Island that show only Class 0 pollution. The enrichment factor(EF) suggested minor to moderately severe metal enrichment by anthropogenic sources in Kota Belud, whereas only minor enrichment in Kudat and Mantanani Island. The modified pollution degree(MCD<1.5) and pollution load index(0 PLI<1) indicating only low pollution level in the marine sediments for all study sites. The objectives of this study are:(1) to determine the physico-chemical parameters of sediments,(2) interpret the heavy metal contents and(3) evaluate the sediment quality.

Comparison of Fatty Acid and Proximate Composition between <i>Holothuria edulis</i>and <i>Holothuria scabra</i>Collected from Coastal Water of Sabah, Malaysia

The nutritional values of different species of sea cucumber are greatly concerned because of their dietary and curative properties. In this study, two species of sea cucumber, Holothuria edulis, a low-valued noncommercial species, and Holothuria scabra, a high-valued commercial species were selected to compare its proximate composition and fatty acids. H. edulis a prevalent species in coastal water of Sabah is not commercially importance like H. scabra. Sea cucumbers were captured live from the Sabah marine habitat. All samples were immediately eviscerated, freeze-dried and stored at 4°C in until analyzed. Silylating agent N, O-Bis(trimethylsilyl) trifluoroacetamide (BSTFA) was used to derivitization of fatty acid prior to gas chromatography-mass spectrometry (GC-MS) analysis. Proximate compositions (%), such as moisture, crude protein, crude lipids and ash were carried using standard methods. Major fatty acids in H. edulis and H. scabra were saturated fatty acid (SFA) accounted for 83.95% and 98.60%, respectively and dominated with Palmitic acids. Polyunsaturated fatty acid (PUFA), arachidonic acid of 16.05% was found only in H. edulis, but absent H. scabra. Proximate compositions (dry weight) were varied greatly within these two species. Moisture, crude protein, crude lipids and ash of 85.5%, 70.5%, 1.37% and 1.27% respectively were obtained in H. edulis. On the other hand 84.5% of moisture, 51.2% of crude protein, 0.27% of crude lipids and 4.44% of ashes were determined in H. scabra. Significantly higher protein (p H. edulis compare to H. scabra could be the choice of option for the utilization of this non commercial species as nutraceutical industry and also alternatives to reduce the pressure on heavily exploited species of H. scabra.

Chemical composition of the Tertiary black shales of West Sabah, East Malaysia

The X-ray fluorescence and ICP methods were used to analyze 60 outcrop samples of black shale, of which 15 were collected from Belait, 15 from the Setap Shale, 15 from Temburong, and 15 from the Trusmadi for- mations. The average compositions of the shales from the study area are 64.62%, 63.95%, 62.32%, 63.84% SiO2, 1.84%, 2.14%, 2.04%, 1.99% MgO, 2.55%, 3.12%, 2.89%, 2.72% K2O, 0.32%, 0.30%, 0.32%, 0.53% CaO, 5.86%, 6.06%, 7.14%, 6.60% Fe2O3, 207×10-6, 180×10-6, 213×10-6, 200×10-6 Rb, and 56×10-6, 49×10-6, 50×10-6, 32×10-6 Sr for the Setap Shale, Temburong, Belait and Trusmadi samples, respectively. The high Rb/Sr ratios of 3.8, 3.7, 4.2, and 6.1 are attributed to the lowest contents of Sr due to reducing conditions prevailing. The high Rb/K ratio sug- gests either brackish marine or rapid deposition that prevented equilibrium between Rb and K in the shales and ma- rine waters.

Occurrence and Distribution of Marsh Clam, <em>Polymesoda</em>spp. in Marudu Bay, Sabah, Malaysia

Marudu Bay is part of the Tun Mustapha Marine Park, the largest marine protected area within the Malaysian region of the Coral Triangle Initiative. The bay is known for its diversed fisheries resources including bivalves. Although some of these bivalve species are commercially important, their occurrence, distribution and stock status in the bay are not well documented. Hence, the current study was conducted to determine the occurrence, distribution and the stock status of marsh clam, Polymerasoda spp. in the mangrove swamp situated at the southernmost of the Marudu Bay. Samplings were carried out at the mangrove swamps which covered an area of 500 sequare meter per sampling site. Two marsh clams species, Polymesoda erosa and P. expansa were found to inhabit the sampling sites. In general, juvenile marsh clams were noticed to dominate the seaward mangrove swamp, whereas the high tidal regions were dominated by adults. The current study also suggested a link in the distribution and the morphometric measurements of the marsh clams with the sediment grain size.

Variations in the Physicochemical Water Parameters and Phytoplankton Community in Coastal Water of Kudat, Sabah, Malaysia

This study was conducted to observe the abundance and distribution of phy-toplankton and temporal and spatial variation physico-chemical water parameters in coastal water of Kudat, Sabah, Malaysia. Water samples and in-situ water quality parameters were taken from five selected locations from May 2019 to February 2020. The sampling location was selected based on human-induced activities such as Marina Resort’s Jetty (ST1), Sabah Ports’ Jetty (ST2), aquaculture cage/pent (ST3), river’s mouth (ST4) and Landung Ayang’s water village (ST5). Water parameters: pH, salinity (ppt), dissolved oxygen (mg/L) temperature (°C) and depth (m) were recorded once every month from the selected station. Identification of phytoplanktonic species and cell density (cell/mL) were determined from collected water samples. Significant differences (p < 0.05) between physicochemical parameters to months were observed during the study period. However, in spatial variations, significant differences (p < 0.05) of pH, dissolved oxygen (mg/L) and temperature (°C) observed. A total of 21 phytoplankton species were identified from the study area, where 4 species belonged to Dinophyceae (HABs blooming species) and 17 species belonged to Bacillariophyceae. The influences of physicochemical water parameters were not significant in phytoplankton diversity and abundance. In addition to these parameters, the nutrients in the water might have important roles in the blooming of phytoplankton, which are essential and vital to address in this type of research.

Assessment of Spatial and Temporal Variations of Water Quality for Future Mariculture Operation in Ambong Bay, Sabah, Malaysia

Study was conducted with the aim to understand the temporal and spatial variations of water quality parameters (temperature, salinity, pH, DO, TSS, NO3-, NO2-, NH3-N and PO4-P, and phytoplankton cell density) in Ambong Bay, Sabah, Malaysia in order to provide reference for future mariculture development in the bay. Samplings were carried out once a month in two stations (coastal and open sea) within the bay for 12 months period from September 2015 to August 2016. Results showed that there were significant differences in pH and NO2- when compared spatially, whereas salinity, DO, TSS, phytoplankton cell density, NO3-, NH3-N, and PO4-P were temporally significant. The fermentation processes by anaerobic bacteria, organic acids from decaying vegetation and acidic clays in the mangrove soils might explain the significant spatial differences in pH and NO2-. The bay was dominated by dinoflagellate, Prorocentrum spp. (mean abundance of 16.23% and 24.44%, respectively) a potentially toxic algae species. Correlation matrix showed that NH3-N was positively correlated with PO4-P (r = 0.475, p < 0.05) but negatively correlated with salinity (r = –0.517, p < 0.01). Besides, salinity was positively correlated with DO (r = 0.505, p < 0.05) and TSS (r = 0.408, p < 0.05). In addition, DO and TSS were also positively correlated (r = 0.451, p < 0.05). Phytoplankton cell density was positively correlated with TSS (r = 0.644, p < 0.01). In general, the water quality in Ambong Bay is within the standard values permitted by the Malaysia Marine Water Quality standard for marine life, fisheries, coral reefs, recreational and mariculture (Class 2), except for NO3-. In conclusion, any mariculture operation to take place in Ambong Bay in the near future should take the temporal variation of the water quality into account. Moreover, effects of toxic phytoplankton to culture fishes should also be taken care and monitored frequently.

Health Risk Assessment Due to Heavy Metals Exposure via Consumption of Bivalves Harvested from Marudu Bay, Malaysia

Concern over health risk from consumption of bivalves originating from Marudu Bay is escalating due to the rapid agricultural development surrounding the bay. This has motivated us to estimate the health risk index (HRI) of heavy metals from four commercially important and highly exploited bivalve species which are abundant in the bay. Samples (n = 30) of green mussel (Perna viridis), Asiatic hard clam (Meretrix meretrix), Pacific oyster (Crassosstrea gigas) and marsh clam (Polymesoda expans) were acquired from fishermen in Kg. Teritipan, Marudu Bay. These bivalves were analyzed for heavy metals content using the Inductively Couples Plasma-Optical Emission Spectroscopy (ICP-OES). The study found that the mean contents of Arsenic (As) and Manganese (Mn) in all analyzed bivalves exceeded the permissible limits as well as copper (Cu), lead (Pb) and zinc (Zn) in Pacific oyster, and Zn in marsh clam. It was also noticed that consumption of different bivalve species may bring about health risk from different metals as indicated by varied Total Hazard Index (THI) values. Consumption of the four bivalves was noticed to promote high health risk from As intoxication. Although metal pollution index (MPI) analysis revealed that the bivalves from the bay are currently not seriously impacted by heavy metal pollution, vigorous efforts should be taken to preserve the natural condition of the bay for years to come. There are several ways to minimize health issues from bivalve consumption which include keeping the bivalve natural habitat away from heavy metals pollution by strictly enforcing environmental laws and policies, establishing zones for bivalve fisheries, monitoring heavy metals concentration in bivalve on a regular basis and making depuration process a compulsory requirement in every seafood restaurant throughout the country.

Sauna Technique, Drying Kinetic Modeling and Effectiveness on Solar Drying Compared with Direct Drying in Drying Process of <i>Kappaphycus striatum</i>in Selakan Island Malaysia

A sauna drying technique—the solar drier was designed and imposed, constructed and tested for drying of seaweed. The seaweed moisture content was decreased around 50% in 2-day sauna. Kinetic curves of drying of seaweed were known to be used in this system. The non-linear regression procedure was used to fit three different drying models. The models were compared with experimental data of red seaweed being dried on the daily average of air temperature about 40℃. The fit quality of the models was evaluated using the coefficient of determination (R2), Mean Bias Error (MBE) and Root Mean Square Error (RMSE). The highest values of R2 (0.99027), the lowest MBE (0.00044) and RMSE (0.03039) indicated that the Page model was the best mathematical model to describe the drying behavior of sauna dried seaweed. The percentage of the saved time using this technique was calculated at 57.9% on the average solar radiation of about 500 W/m2 and air flow rate of 0.056 kg/s.

Malaysia＇s Contemporary Political and Economic Relations with Iran

Traditionally, Malaysia＇s relations with the Middle Eastern World boil down to narrow-limited interaction with only a handful of countries, mainly Egypt, Saudi Arabia （before known as Hejaz）, and Turkey. The underlying reasons behind are largely owing to the established ancient relations and religious fulfillments like performing pilgrimage as well as pursuing religious studies in highly respected institutions. Malaysia＇s relation with the Islamic Republic of Iran, however, has shown steady progress of development since the end of 1960s and onwards. Although Iran has become an Islamic Republic after the eruption of the Revolution in 1979, the relations remain intact in spite of the potential expansion of Iran＇s religious ideology, Shi＇ah, among Malaysian Muslim communities. On top of that, with Iran now facing economic sanctions due to its nuclear programs, both countries continue to bolster their relations, especially in political and economic interactions. Contemporarily, both Malaysia and Iran are closely working together to further enhance the level of their relations. The leaders of both countries have quiet regularly exchanged visits and have also actively ventured into promising business opportunities. Iran ranked as the Malaysia＇s third West Asian trading partners along with the United Arab Emirates （UAE） and Saudi Arabia, provides a lot of opportunities for Malaysia to seize onto. In other words, Malaysia＇s contemporary relations with Iran will evolve beyond the dogma of the Iranian Revolution in 1979.

Genetic variations of Chrysomya megacephala populations in Malaysia (Diptera: Calliphoridae)

Samples of Chrysomya megacephala were collected from five sites in Malaysia, namely Penang, Selangor, Pahang, Johor, and Sabah. Molecular analysis was conducted using the cytochrome oxidase gene and ISSR-PCR to identify polymorphic markers for distinguishing the populations and to estimate the genetic relatedness among these populations. Two SNPs were detected at sequence position 952 (M1) and 1120 (M2), involving transitional substitutions with cytosine (C) being replaced with thymine (T) and guanine (G) replaced with adenine (A), but there was no amino acid variation. Penang and Selangor shared the same nucleotide T at the M1 position, while M2 variation was found in Pahang population only. The NJ tree based on the COI sequence showed two main groups with branch A comprised of Penang and Selangor populations while branch B consisted of Johor, Pahang and Sabah populations. ISSR analysis indicated that 18 scorable bands (size 200 to 1800 bp) were amplified with UBC808 and UBC835, 11 bands of which were polymorphic and the rest monomorphic. Sabah population was left out for further analysis due to small number of specimens. UPGMA dendrogram using ISSR data showed two branches, one consisted of Penang and Selangor populations, while the other consisted of Pahang and Johor individuals. The polymorphic loci (P) for Johor Baru were 5.56%, Penang 16.70%, Selangor and Pahang 22.2%. Nei’s H values are respectively 0.018, 0.060, 0.050 and 0.051. Similarly the Shannon index diversity values are respectively 0.028, 0.089, 0.085 and 0.087. The lowest genetic distance (0.0997) was between Penang and Selangor populations, while the highest (0.613) was observed between Penang and Pahang populations. AMOVA shows low genetic differentiation among individuals within populations and that 85.6% of total genetic variance was among individuals between populations. This was also indicated by FST statistic of 0.8562. The gene flow between populations was low with Nm of 0.042, and Mantel’s test indicated a significant correlation between genetic distance and log geographic distance (P < 0.05 from 10,000 randomizations). In conclusion the Penang and Selangor fly populations are similar genetically, compared to the other populations.

Population dynamics and condition index of natural stock of blood cockle,Tegillarca granosa(Mollusca,Bivalvia,Arcidae)in the Marudu Bay,Malaysia

The population parameters of blood cockles,Tegillarca granosa in the intertidal zone of Marudu Bay,Sabah,Malaysia were investigated based on monthly length-weight frequency data(July 2017 to June 2018).A total of 279 cockle individuals with shell length and weight ranging from 27.7 mm to 82.2 mm and 13.11 g to 192.7 g were subjected to analysis.T.granosa in Marudu Bay showed a consistent moderately high condition index 4.98±0.86 throughout the year.The exponent b of the length-weight relationship was 2.6 demonstrating negative allometric growth.The estimated asymptotic length(L_(∞)),growth coefficient(K)and growth performance(Ф)of the T.granosa population in Marudu Bay were estimated at 86.68 mm,0.98 a^(-1) and 3.87,respectively.The observed maximum shell length was 82.55 mm and the predicted maximum shell length was 84.44 mm with estimated maximum life span(t_(max))of 3.06 years.The estimated mean lengths at the end of 2,4,6,8,10 and 12 months of age were 21.31 mm,31.16 mm,39.53 mm,46.63 mm,52.67 mm and 57.79 mm.Total,natural,and fishing mortalities were estimated at 2.39 a^(-1),1.32 a^(-1) and 1.07 a^(-1).The exploitation level(E)was 0.45.Results of the current study also demonstrated that T.granosa in the Marudu Bay has two major recruitment peaks;one in March and another in October.The exploitation level revealed that natural stock of T.granosa in the Marudu Bay was approaching the maximum exploitation level.If such trend continues or demand for T.granosa is increasing,coupled with no effective fisheries management in place,possibility of the T.granosa population in the Marudu Bay to collapse is likely to elevate.

Phytoplankton diversity in a tropical bay,North Borneo,Malaysia as revealed by light microscopy and Next-Generation Sequencing

Assessments of phytoplankton diversity in Sabah waters,North Borneo,have primarily relied on morphology-based identification,which has inherent biases and can be time-consuming.Next-Generation Sequencing(NGS)technology has been shown to be capable of overcoming several limitations of morphology-based methods.Samples were collected from the Sepanggar Bay over the course of the year 2018 in different monsoon seasons.Morphology-based identification and NGS sequencing of the V8–V9 region of the 18S LSU rDNA were used to investigate the diversity of the phytoplankton community.Microscopy and NGS showed complementary results with more diatom taxa detected by microscopy whereas NGS detected smaller and rarer taxa.The harmful algal genera in the study site comprised of Skeletonema,Margalefidinium,Pyrodinium,Takayama,and Alexandrium as detected by NGS.This study showed that that an integrative approach of both morphological and molecular techniques could provide more comprehensive information about the phytoplankton community as the approach captured quantitative variability as well as the diversity of phytoplankton species.

Refinement Mechanism of Microstructure of Undercooled Nickel Based Alloys

Through the use of purification and recirculation superheating techniques on molten glass,the Ni65Cu33Co2 alloy was successfully undercooled to a maximum temperature of 292 K.High-speed photography was employed to capture the process of interface migration of the alloy liquid,allowing for an analysis of the relationship between the morphological characteristics of the alloy liquid solidification front and the degree of undercooling.Additionally,the microstructure of the alloy was examined using metallographic microscopy,leading to a systematic study of the microscopic morphological characteristics and evolution laws of the refined structure during rapid solidification.The research reveals that the grain refining mechanism of the Ni-Cu-Co ternary alloy is consistent with that of the binary alloy(Ni-Cu).Specifically,under low undercooling conditions,intense dendritic remelting was found to cause grain refinement,while under high undercooling conditions,recrystallization driven by accumulated stress and plastic strain resulting from the interaction between the liquid flow and the primary dendrites caused by rapid solidification was identified as the main factor contributing to grain refinement.Furthermore,the study highlights the significant role of the Co element in influencing the solidification rate and reheat effect of the alloy.The addition of Co was also found to facilitate the formation of non-segregated solidification structure,indicating its importance in the overall solidification process.

Privacy-Preserving Information Fusion Technique for Device to Server-Enabled Communication in the Internet of Things:A Hybrid Approach

Due to the overwhelming characteristics of the Internet of Things(IoT)and its adoption in approximately every aspect of our lives,the concept of individual devices’privacy has gained prominent attention from both customers,i.e.,people,and industries as wearable devices collect sensitive information about patients(both admitted and outdoor)in smart healthcare infrastructures.In addition to privacy,outliers or noise are among the crucial issues,which are directly correlated with IoT infrastructures,as most member devices are resource-limited and could generate or transmit false data that is required to be refined before processing,i.e.,transmitting.Therefore,the development of privacy-preserving information fusion techniques is highly encouraged,especially those designed for smart IoT-enabled domains.In this paper,we are going to present an effective hybrid approach that can refine raw data values captured by the respectivemember device before transmission while preserving its privacy through the utilization of the differential privacy technique in IoT infrastructures.Sliding window,i.e.,δi based dynamic programming methodology,is implemented at the device level to ensure precise and accurate detection of outliers or noisy data,and refine it prior to activation of the respective transmission activity.Additionally,an appropriate privacy budget has been selected,which is enough to ensure the privacy of every individualmodule,i.e.,a wearable device such as a smartwatch attached to the patient’s body.In contrast,the end module,i.e.,the server in this case,can extract important information with approximately the maximum level of accuracy.Moreover,refined data has been processed by adding an appropriate nose through the Laplace mechanism to make it useless or meaningless for the adversary modules in the IoT.The proposed hybrid approach is trusted from both the device’s privacy and the integrity of the transmitted information perspectives.Simulation and analytical results have proved that the proposed privacy-preserving information fusion technique for wearable devices is an ideal solution for resource-constrained infrastructures such as IoT and the Internet ofMedical Things,where both device privacy and information integrity are important.Finally,the proposed hybrid approach is proven against well-known intruder attacks,especially those related to the privacy of the respective device in IoT infrastructures.

Growth Characteristics of Phototrophic Bacterium Afifella marina in Wastewater

Nutrients available in wastewater are supportive for the growth of phototrophic bacteria. Phototrophic bacterium, Afifella marina strain ME was grown in a characterized finfish hatchery wastewater. The effects of three light intensities (2000 lux, 2500 lux and 3000 lux) with 30% (v/v) inoculum on the growth, in terms of dry cell weight (g/L) and production of total carotenoids (mg/g dry cell weight) were observed in this study. Total nitrogen (mg/L) and phosphorus (mg/L) are the two major nutrients identified in wastewater. The highest bacterial cell weight of 0.37 g/L was obtained after 72 hours of culture at 2500 lux light intensity, whilst the highest total carotenoid production of 0.06 mg/g dry cell weight was determined in 24 hours of culture at same light intensity. Different light intensities affected the production of bacterial cell weight and total carotenoid production. However, statistical analysis indicated that there were no significant differences between bacterial dry cell weight and total carotenoid production due to the differing light intensities (p > 0.05). Poor growth (dry cell weight) and carotenoids production with low SGR, but efficient use of substrate. The 30% (v/v) inoculum level observed was not very supportive on the growth characteristics of bacterium. In addition, other opportunities for bacteria that remained in wastewater might suppressed the growth of Afifella marina strain ME, which need further investigation. Further, several other factors like, strain type, temperature of the culture substrate, nutrients and types of inoculum media, aerobic and anaerobic culture condition and agitation speed can alter and change the growth profile of bacterium, which need to be optimized. However, phototrophic bacterium Afifella marina strains ME is capable to grow in finfish in all these three light intensities but not at 30% (v/v) inoculum level.

浅析新能源汽车发展

本文回顾了新能源汽车的发展,分析了新能源汽车的现状,并展望了新能源汽车的未来。在文中对新能源汽车的概念、发展历程和特点进行了介绍;对新能源汽车的纯电动车技术、插电式混合动力车技术、燃料电池车技术、动力电池技术、电机技术、电控技术、新能源汽车销售等的现状进行了分析;以及对新能源汽车的发展前景进行了展望。

Effects of light intensities and photoperiods on growth and proteolytic activity in purple non-sulfur marine bacterium, <i>Afifella marina</i>strain ME (KC205142)

Afifella marina strain ME (KC205142), a purple non-sulfur bacterium was isolated from mangrove habitats of Sabah. The effects of light intensities and photoperiods on proteolytic activity in Afifella marina strain ME (KC205142) were investigated. Secretion of proteolytic enzymes in Afifella marina was preliminarily assessed by skim milk agarose media. Subsequently, light intensities, such as, dark, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500 and 5000 lux were used to evaluate the effects on proteolytic activity in Afifella marina strain ME under anaerobic condition. After that, the effect of photoperiods on proteolytic activity was monitored under anaerobic light condition (3000 lux) at 0 h (0L/24D), 6 h (6L/18D), 12 h (12L/12D), 18 h (18L/6D) and 24 h (24L/0D) of photoperiod. The highest proteolytic activity of 74.67 U was recorded at 3000 lux illumination light intensity. The proteolytic activity in bacterium Afifella marina strain ME was positively associated with the dry cell weight. The proteolytic activity of 72.67 U in bacterium Afifella marina strain ME at 18 h (18L/6D) photoperiod is not significantly different (p > 0.05) from proteolytic activity of 74.67 U recorded at continuous light (24L/0D) condition. Light intensity of 3000 lux, culture period of 48 h and a photoperiod of 18 h (18L/ 6D) were the optimum parameters for proteolytic activity in bacterium Afifella marina strain ME.

Microstructure Transition and Grain Refinement Mechanism of Undercooled Alloys

The solidification microstructures of undercooled Ni90Cu10 alloys under different undercoolings were studied systematically by means of melt coating and cyclic superheating.In the obtained undercooling range,the solidification structures of the two undercooled alloys have similar transformation processes,and there are two kinds of grain refinement structures under the conditions of low undercooling and high undercooling,respectively.The microstructures of the two grain refinement processes were analyzed in more detail by electronic backscattering diffraction technique.Under the condition of small undercooling,dendrite remelting is considered to be the main reason of grain refinement.However,under the condition of high undercooling,the existence of annealing twins and obvious migration of grain boundary are important evidences for the occurrence of recrystallization process.