Influence of humic acid on sorption of Co(II), Sr(II), and Se(IV) on goethite

Abstract

This work examined the influence of a leonardite humic acid on the sorption of Co(II), Sr(II), and Se(IV) onto goethite as a function of pH. The sorption of humic acid and ions alone was first studied. The humic acid sorbs appreciably to the goethite surface according to a reversible process, with a maximum sorption of 19 mg of total organic carbon per g of goethite reached at lower pH values (» 5). Cobalt and selenium are significantly sorbed on goethite while strontium is only weakly sorbed. In the presence of humic acid, the cobalt sorption is enhanced in acidic media due to the humic acid sorption on goethite, which modified the surface properties by making it more negative. However, it decreases in alkaline media due to the complexation of Co(II) by soluble humic acid. The sorption of Sr(II) is significantly increased in the presence of humic acid even in alkaline media. The sorption of selenite ions (SeO3 2–) decreases in the presence of humic acid because a competition with humate ions occurs at the surface sites of the goethite. The results presented here constitute a good set of data for modelling the effect of humic acid on the sorption of ions on goethite.

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How DOC Composition May Explain the Poor Correlation Between Specific Trihalomethane Formation Potential and Specific UV Absorbance

Abstract

Trihalomethane formation potential, ultra-violet light absorbance, and aromatic carbon content of dissolved organic carbon in natural water from grab sampling in watersheds across the USA and from detailed sampling in one watershed, the Sacramento-San Joaquin Delta, California, were examined in order to better understand the compositional nature of trihalomethane precursor material. Specific trihalomethane formation potential and specific ultra-violet light absorbance were not tightly correlated in either dataset, indicating that ultra-violet light absorbance cannot be used for accurate prediction of specific trihalomethane formation potential in drinking water derived from a broad spectrum of watershed types. Specific trihalomethane formation potential was not closely related to the aromatic carbon content of dissolved organic carbon isolates or to the partitioning of the dissolved organic carbon by nonionic macroporous resins, suggesting that neither of these measures are related to the compositional features of the dissolved organic carbon responsible for trihalomethane formation.

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Fluorescence properties of organic ligands for copper(II) in Lake Biwa and its rivers

Abstract

Organic ligands for copper(II) were isolated from lake waters in Lake Biwa and its river waters by immobilized metal ion affinity chromatography (IMAC), and were characterized by three-dimensional excitation/emission matrix spectroscopy (3DEEM) and fluorescence quenching titration. The results show that the contribution of total organic ligands was 0.63–4.68% of the bulk dissolved organic matter (DOM), in terms of UV absorbance, in lake and river waters. Three characteristic excitation/emission (Ex/Em) fluorescence peaks were identified in organic ligands from both lake and river waters, at Ex/Em 310–330/ 374–434 nm (Peak A), 250/414–454 nm (Peak B), and 260–270/306–330 nm (Peak C). Peaks A and B were referred to as humic-like fluorescence, Peak C as protein-like fluorescence. All Ex/Em maxima of organic ligands in lake waters were shifted towards shorter wavelength, and the fluorescence intensities were higher than those in river waters. The results of fluorescence quenching titration show that the IMAC ligands were weak ligands, with conditional stability constants (logK′CuL) around 7.27 for river ligands, and 7.84–9.23 for lake ligands. The differences of fluorescence properties indicate the variability of fluorescent ligands between river terrestrial and lake aquatic environments.

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Hydrolyzing metal salts as coagulants

Abstract

Aluminium and ferric salts are widely used as coagulants in water and wastewater treatment. They are effective in removing a broad range of impurities from water, including colloidal particles and dissolved organic substances. Their mode of action is broadly understood in terms of essentially two mechanisms: charge neutralization of negatively charged colloids by cationic hydrolysis products and incorporation of impurities in an amorphous precipitate of metal hydroxide. The relative importance of these two mechanisms depends on many factors, especially pH and coagulant dosage. Alternative coagulants based on prehydrolyzed forms of aluminium or iron can be more effective than the traditional materials in many cases, but their mode of action is not completely understood, especially with regard to the role of charge neutralization and hydroxide precipitation. Basic principles of colloid stability and metal ion hydrolysis are briefly reviewed, and the action of hydrolyzing metal coagulants is then discussed, with some examples from recent experimental studies. Although it is possible to interpret results reasonably well in terms of established ideas, there are still some uncertainties that need to be resolved.

Keyword: Hydrolyzing, metal salts, coagulants

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Kesetimbangan Adsorpsi Optional Campuran Biner Cd(II) dan Cr(III) dengan Zeolit Alam Terimpregnasi 2-merkaptobenzotiazol

ABSTRACT

Natural zeolite is one of adsorbents widely used in adsorption processes to treat water polution caused by heavy metal waste. In some cases, the modification of the zeolit active surface is important to improve its adsorpability and its selectivity. Characteristic of modified natural zeolite can be obtained from the analysis of adsorption equilibrium data which useful for adsorption process design. The aim of the research is to find and analyzing the adsorption equilibrium data for binary mixture adsorption process of Cd and Cr metals using the modified natural zeolite which impregnated with 2-metrcaptobenzotiazole (zeolite-MBT). The adsorption equilibrium experiments were carried out in a flask batch method using a shaker bath with experimental temperatures were varied from 27°C to 50°C. An amount of 0.1 gram of zeolite-MBT adsorbent was immersed in 60 ml of Cd and or Cr solution then shook until the equilibrium condition (6 hours) was reached. The quantity of metal ionic adsorbed was measured through the concentration of metal solution at equilibrium condition. Each series of equilibrium data were obtained by varying the initial solution concentration in such a way that they could be ploted to create the adsorption isotherm curve. The Langmuir competitif model was used to draw the adsorption isotherm curve for the binary mixture of Cd and Cr by zeolit-MBT adsorbent. The smallest relative mean error correction, i.e. 12.9% and 23 % for Cd and Cr adsorption respectively. Separation performance in the adsorption process of Cd and Cr by the zeolit-MBT adsorbent is five to eight times better than the zeolit-Na adsorbent that wide commercially being used.

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Palladium-Catalyzed Alkylation of Unactivated Olefins

Abstract

Reaction of a 3-butenyl -diketone with a catalytic amount of PdCl2(CH3CN)2 in dioxane at room temperature led to olefin hydroalkylation and formation of the corresponding 2-acylcyclohexanone in good yield as a single regioisomer. Deuterium-labeling experiments for the hydroalkylation of 7-octene-2,4-dione were in accord with a mechanism involving outer-sphere attack of the pendant enol on a palladium-complexed olefin to form a palladium cyclohexyl species, followed by palladium migration via iterative -hydride elimination/ addition and protonolysis from a palladium enolate complex. In comparison to a 3-butenyl -diketone, reaction of a 4-pentenyl -diketone with a catalytic amount of PdCl2(CH3CN)2 in the presence of CuCl2 led to oxidative alkylation and formation of the corresponding 2-acyl-3-methyl-2-cyclohexenone in good yield as a single isomer.

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Perry’s Chemical Engineer’s Handbook: Adsorption and Ion Exchange

Introductions

Adsorption and ion exchange share so many common features in regard to application in batch and fixed-bed processes that they can be grouped together as sorption for a unified treatment. These processes involve the transfer and resulting distribution of one or more solutes between a fluid phase and particles. The partitioning of a single solute between fluid and sorbed phases or the selectivity of a sorbent toward multiple solutes makes it possible to separate solutes from a bulk fluid phase or from one another.

This section treats batch and fixed-bed operations and reviews process cycles and equipment. As the processes indicate, fixed-bed operation with the sorbent in granule, bead, or pellet form is the predominant way of conducting sorption separations and purifications. Although the fixed-bed mode is highly useful, its analysis is complex. Therefore, fixed beds including chromatographic separations are given primary attention here with respect to both interpretation and prediction.

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ELEMENTARY LINEAR ALGEBRA

ELEMENTARY LINEAR ALGEBRA

*K. R. Matthews

 

1. Introduction to linear equations

A linear equation in n unknowns x1. x2,..., xn is an equation of the form

a1x1 + a2x2 + ... + anxn = b,

where a1, a2, ..., an, b are given real numbers.

For example, with x and y instead of x1 and x2, the linear equation 2x + 3y = 6 describes the line passing through the points (3; 0) and (0; 2). 

Similarly, with x; y and z instead of x1; x2 and x3, the linear equation 2x + 3y + 4z = 12 describes the plane passing through the points (6; 0; 0); (0; 4; 0); (0; 0; 3).

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Program Dinamik

Abstract

Tidak seperti program linier, Program Dinamik (PD) tidak mempunyai standar formulasi matematik. PD lebih merupakan suatu cara umum untuk melakukan optimasi dengan persamaan matematik yang cocok dengan masalah yang dihadapi. Insight dan ingenuity dibutuhkan untuk mengenali penggunaan PD dalam menyelesaikan masalah lapangan. Cara terbaik penyampaian PD adalah dengan mengenalkan beberapa permasalahan yang dapat diselesaikan dengan PD.

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METODE OPTIMASI SELEKSI FITUR DENGAN ALGORITMA FAST BRANCH AND BOUND

Abstract

Integer Programming merupakan salah satu pemodelan untuk pencarian suatu solusi yang optimum dari suatu masalah. Banyak sekali kasus di sekitar kita yang memerlukan implementasi integer programming agar didapatkan suatu solusi paling optimal yang pada akhirnya menambah keuntungan. Ada banyak cara untuk menyelesaikan integer programming, misalnya dengan cara program linear standar yaitu dengan menggunakan grafik. Cara lainnya adalah dengan mengaplikasikan algoritma Branch and Bound. Makalah ini mencoba untuk menjelaskan bagaimana suatu integer programming diselesaikan dengan pengaplikasian algoritma Branch and Bound.

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Penggunaan Metode Branch And Bound With Search Tree Untuk Menyelesaikan Persoalan Pedagang Keliling Pada Graf Lengkap Sebagai Pengganti Metode Exhaustive Enumeration

Abstract

Persoalan pedagang keliling merupakan persoalan yang cukup terkenal di dalam teori graf, Implementasinya sangat banyak digunakan di dalam kehidupan sehari-hari, dari masalah yang berhubungan dengan pengiriman barang sampai yang berhubungan dengan industri pabrik Oleh karena itu, saya memilih persoalan ini sebagai tema dari makalah saya. Saya juga membatasi masalah yang ada yaitu pemecahan TSP graf lengkap (Kn) untuk lebih memberikan kejelasan yang dalam. Makalah ini membahas sebuah metode yang dapat digunakan untuk menyelesaikan persoalaan pedagang keliling (TSP) pada graf lengkap. Kita dapat melihat kemampuan dari metode ini dalam memecahkan persoalaan dari segi kompleksitas waktu dan kemudahan dalam penggunaan. 

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APLIKASI ALGORITMA BRANCH AND BOUND UNTUK MENYELESAIKAN INTEGER PROGRAMMING

Abstract

Integer Programming merupakan salah satu pemodelan untuk pencarian suatu solusi yang optimum dari suatu masalah. Banyak sekali kasus di sekitar kita yang memerlukan implementasi integer programming agar didapatkan suatu solusi paling optimal yang pada akhirnya menambah keuntungan. Ada banyak cara untuk menyelesaikan integer programming, misalnya dengan cara program linear standar yaitu dengan menggunakan grafik. Cara lainnya adalah dengan mengaplikasikan algoritma Branch and Bound. Makalah ini mencoba untuk menjelaskan bagaimana suatu integer programming diselesaikan dengan pengaplikasian algoritma Branch and Bound. 

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TEKNIK RISET OPERASI: Pengembangan Teknologi Komputer & Informasi sebagai Langkah Rehabilitasi Tuna Netra di Indonesia

Abstract

Indera penglihatan adalah salah satu sumber informasi vital bagi manusia. Tidak berlebihan apabila dikemukakan bahwa sebagian besar informasi yang diperoleh oleh manusia berasal dari indera penglihatan, sedangkan selebihnya berasal dari panca indera yang lain. Dengan demikian, dapat dipahami bila seseorang mengalami gangguan pada indera penglihatan, maka kemampuan aktifitasnya akan jadi sangat terbatas, karena informasi yang diperoleh akan jauh berkurang dibandingkan mereka yang berpenglihatan normal. Hal ini, apabila tidak mendapat penanganan/rehabilitasi khusus, akan mengakibatkan timbulnya berbagai kendala psikologis, seperti misalnya perasaan inferior, depresi, atau perasaan hilangnya makna hidup. 

Di Indonesia alat bantuk utama untuk tuna netra yaitu tongkat khusus. Akan tetapi alat ini memiliki berbagai macam keterbatasan, sehingga hanya sebagian kecil saja informasi yang dapat dipahami dari lingkungan dimana dia berada. Dewasa ini, perkembangan teknologi yang pesat membuka peluang pengembangan berbagai alat bantu yang memanfaatkan berbagai disiplin ilmu, seperti halnya GPS, computer vision, virtual reality, SMS Speech, serta berbagai perangkat lunak dan perangkat keras ntuk memberikan informasi yang lebih utuh bagi tuna netra.

 

Keyword: Teknik Riset Operasi, Teknologi Komputer, Rehabilitasi Tuna Netra

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TINGKAT MOTILITAS SPERMATOZOA DAN PEMBUAHAN SEL TELUR TIRAM MUTIARA (Pinctada maxima) DENGAN PEMBERIAN LARUTAN AMONIA

Abstract

Indonesia merupakan negara kepulauan yang memiliki perairan yang luas sehingga mempunyai potensi yang cukup besar untuk pemanfaatan sumber hayati laut yang terkandung didalamnya, salah satu potensi besar yang ada diperairan Indonesia adalah tiram mutiara. Seiring dengan bertambahnya usaha budidaya tiram mutiara maka meningkat pula kebutuhan akan pengadaan benih tiram mutiara, dan sampai saat ini pengadaan benih masih banyak tergantung dari alam. Untuk mengatasinya maka perlu dilakukan usaha pembenihan yang dapat menjamin kelangsungan usaha budidaya tiram mutiara dan dapat menjaga kelestarian komoditas tersebut dari kepunahan. Tujuan dari penelitian ini adalah mengetahui tingkat motilitas spermatozoa dengan penambahan larutan ammonia, mengetahui tingkat keberhasilan pembuahan sel telur oleh spermatozoa yang telah mendapatkan perlakuan penambahan larutan ammonia dan mendapatkan konsentrasi larutan ammonia yang paling tepat untuk meningkatkan persentase pembuahan sel telur tiram mutiara. 

Rancangan percobaan yang digunakan dalam penelitian aini adalah rancangan acak lengkap (RAL) dengan lima perlakuan dan tiga kali ulangan, perlakuan yang diberikan adalah pemberian konsentrasi larutan ammonia yang berbeda. Konsentrasi yang digunakan adalah 0 % ,0,05%, 0,1 %, 0,15 % dan 0,2 % dari volume sampel. Hasil penelitian menunjukan bahwa semua perlakuan yang dicobakan memberikan perbedaan pengaruh yang sangat nyata terhadap motilitas spermatozoa dan pembuahan sel telur tiram mutiara.

Kata kunci : amonia,motilitas,pembuahan,tiram mutiara

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Efek Sitotoksik Suatu Protein Seperti Ribosome Inactivating Proteins yang Bersifat Asam dari Daun Mirabilis Jalapa L. Pada Sel Kanker

Cytotoxic effects of an acidic Ribosome-inactivating Protein like protein isolated from Mirabilis jalapa L. leaves on cancer cell-lines

Sudjadi *, Lucia D Witasari, Modesta T Sadarum, Nia Nastity dan Sismindari

Fakultas Farmasi Universitas Gadjah Mada Yogyakarta

Abstract

Most purification approaches of Ribosome-inactivating Proteins (RIPs) used a cation exchange chromatography resulting highly basic proteins, such as MJ-30 isolated from Mirabilis jalapa leaves. The M.jalapa unbounded protein fractions of the column showed cleavage activity on supercoiled double stranded DNA and possesed cytotoxic effects on cancer cell lines. So the purification and characterization of the acidic protein was needed to be done. Total proteins of M.jalapa leaves was collected from precipitating process of the extract using ammonium sulphate untill saturated. After dialysis, the proteins was applied into the weak base anion exchanger Ionenaustaucher Typ II. The bounded proteins was eluted with 0.0 to 0.5 M NaCl gradient in phosphate buffer. Active protein fractions were determined by supercoilded DNA cleavage activity and then cytotoxic activity was testes. Results showed that protein fraction eluted at 0.35 – 0.40 M NaCl possesed cleavage activity on supercoiled DNA. The acidic protein, MJ-C, was toxic on HeLa, Myeloma and T47D cell lines, with the LC50 of 4.3 μg/mL, 7.4 μg/mL and 27.8 μg/mL, respectively. The MJ-C was more potent than the basic protein MJ-30.

Keyword : acidic RIP, cytotoxic, Mirabilis jalapa,

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Beberapa Oligomer Stilbenoid dari Tumbuhan Shorea multiflora Burck

Abstract

Two dimers of stilbenoids, (-)-balanocarpol (4), and (-)-ampelopsin A (5), along with a tetramer (-)-hopeaphenol (6) were isolated from the stem bark of Shorea multiflora Burck (Dipterocarpaceae), locally known as Meranti. Their structures were determined by physical and UV, IR, 1H-NMR, and 13C-NMR spectroscopic data.

Keyword : (-)-ampelopsin A, (-)-balanocarpol, Dipterocarpaceae, (-)-hopeaphenol, Meranti, Shorea multiflora Burck.

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ESTERIFIKASI PATCHOULI ALKOHOL HASIL ISOLASI DARI MINYAK DAUN NILAM (PATCHOULI OIL)

Abstract

Minyak atsiri yang disebut juga minyak eteris atau minyak terbang banyak diperlukan dalam kehidupan sehari-hari. Dengan kemajuan teknologi di bidang minyak atsiri maka usaha penggalian sumber-sumber minyak atsiri dan pendayagunaannya dalam kehidupan manusia semakin meningkat. Minyak atsiri tersebut digunakan sebagai bahan pengharum atau pewangi pada makanan, sabun, pasta gigi, wangi-wangian dan obat-obatan. Untuk memenuhi kebutuhan itu, sebagian besar minyak atsiri diambil dari berbagai jenis tanaman penghasil minyak atsiri.

Nilam (Pooostemon cablin BENTH ) merupakan salah satu jenis tanaman yang dapat menghasilkan, minyak atsiri dan sudah lama dikenal oleh masyarakat Indonesia yaitu sebagai pengharum pakaian. Di setiap daerah, nilai mempunyai nama berbeda-beda, di Purwokerto disebut dengan "dilem wangi", di Tapanuli Selatan disebut "singgolom", sedangkan untuk nilam yang berbunga di Jawa sering disebut "dilem kembang" dan di Aceh dikenal dengan nama "nilam bukit" (Poqostemon hevneanus BENTH). Nilam selain dapat dijual dalam bentuk daun kering juga dapat berupa minyak.

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Comparative evaluation of physicochemical qualities of flours from steam-processed yam tubers

Abstract

Three factors were comparatively evaluated during the atmospheric steaming of yam tubers and down-stream processing of the resultant flours. White yam (Dioscorea rotundata Poir), water yam (D. alata L.) and yellow yam (D. cayenensis Lam) tubers were used for this investigation. The effects of yam tuber variety (white, water and yellow), tuber steaming time (30, 60, 90, 120 min) and flour particle size (75, 125, 150, 180, 250, 375, 500 mm) on the physicochemical quality of yam flour were studied. The magnitude and extent of the factorial influence were measured/conducted using the effects on water absorption capacity, swelling index, iodine affinity of starch, solubility and gelatinization temperature. All three variables were observed to cause significant differences (P40.05)in all the test parameters of flour. Based on the results, it is recommended that (from an economic standpoint) tubers of water/yellow yam be steamed at a minimal time of 60 min and pulverized into flours of particle sizes of not less than 75 mm and not more than 375 mm. This combination will give rise to a steamed yam flour sample which exhibits optimum physicochemical characteristics.

Keywords: Comparative evaluation; Yam tuber variety; Steaming time; Particle size; Yam flour; Physico-chemical quality

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Effect of precooking time and drying temperature on the physico-chemical characteristics and in-vitro carbohydrate digestibility of taro flour

Abstract

Achu is a thick porridge obtained by cooking and pounding taro (Colocasia esculenta) corms and cormels in a mortar. This study was undertaken with the objective of producing precooked taro flour that can be used in the preparation of achu. Taro slices were precooked to times of 0, 20, 45 and 90 min and dried in an air convection oven at varying temperatures of 50, 60, 70 or 80 1C before milling into flour which was then analysed for its water absorption capacity (WAC), water solubility index, emulsion activity and stability, bulk density, foam capacity and least gelation concentration (LGC). Achu made from the flours were equally analysed for their relative penetrometric index, bulk density and colour. The results showed that precooking induced significant (Po0:05) decrease in foam capacity, penetrometric index, and increase in LGC, emulsion stability and WAC. The drying  temperature also induces significant reduction in emulsion capacity and stability, penetrometric index,  and increase in LGC, WAC. Long precooking time (445 min) and drying temperature (460 1C)  induced significant reduction of the in-vitro carbohydrate digestibility of taro achu.  

Keywords: Taro flour; Food processing; Physico-chemical properties; In-vitro carbohydrate digestibility

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Influence of partial substitution of wheat flour with vetch (Lathyrus sativus L) flour on quality characteristics of doughnuts

Abstract

Partial substitution of wheat flour (Triticum aestivum) with vetch flour (Lathyrus sativus L) at the levels of 5, 10, 15 and 20 g/100 g was carried out to determine its influence on physico-chemical, rheological, nutritional and sensory characteristics of composite flour doughnuts. Commercial wheat variety, Inqlab-91 was found suitable for the preparation of doughnuts. Sensory and objective evaluations (weight, volume and specific volume) of doughnuts were carried out to evaluate the acceptability of doughnuts. Protein, lysine and trypsin inhibitor contents increased significantly (Po0.05) from 12.10 to 13.84 g/100 g, 2.46–3.58 g/100 g protein and 173 to 187 TIU/g on increasing the level of vetch flour from 0 to 15 g/100 g in the doughnuts, respectively. In vitro protein digestibility of doughnuts was also found to increase (71.8–76.3 g/100 g). It was inferred that doughnuts supplemented with vetch flour up to the level of 15 g/100 g were sensorily acceptable.

Keywords: Vetch; Lathyrus sativus; Wheat flour; Doughnut; Lysine; Trpsin inhibitor

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Impact of endogenous constituents from different flour milling streams on dough rheology and semi-sweet biscuit making potential by partial substitution of a commercial soft wheat flour

Abstract

A flour fractionation-reconstitution procedure was used to study the substitution of a commercial soft wheat flour with gluten, water extractables, prime starch and starch tailing fractions isolated from patent and clear flour streams on dough rheology and semi-sweet biscuit characteristics. Substitution of soft wheat flour with increasing levels of the native patent and clear flour streams raised the dough consistency, hardness and elastic properties as well as the biscuit textural attributes (density, hardness).The dough stickiness of the base flour was also reduced and the biscuits were free of cracks. Gluten isolated from the patent flour had a greater impact on dough consistency, hardness and elastic properties than gluten obtained from the clear flour, likely due to the superior protein quality of the former. Additionally, with increasing gluten levels in the fortified flour there were moderate increases in biscuit density, hardness, and lower crunchiness. The addition of starch tailings produced the largest impact on consistency and hardness of the dough. This fraction also exerted a pronounced effect on biscuit density and hardness, while it lowered crunchiness, presumably due to its higher pentosan content. Overall, the dough rheological properties and biscuit characteristics were controlled by the amountnature of the fractions added; i.e., besides gluten (amount and quality), other constituents such as pentosans and the overall composition of the flour blends can largely affect the quality of the semisweet biscuits. 

Keywords: Soft wheat flour, Milling streams, Flour fortification, Dough rheology, Semi-sweet biscuit, Mechanical properties

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Production of acidic extruded rice flour and its influence on the qualities of gluten-free bread

Abstract

One of the greatest technological challenges in the production of gluten-free bread (GFB) is to find a lowcost ingredient capable of retaining gas during fermentation and the baking process. The use of gelatinized starch appears to show promise for this purpose. In this study, GFB was made using raw rice flour (100 g) with the addition of 10 g acidic extruded rice flour (AERF). The AERF was produced in a singlescrew extruder, varying the extrusion temperature and lactic acid concentration. Response surface methodology (RSM) and the principle components analysis (PCA) were used to analyze the results. The results of RSM showed no significant difference, but the mean volume obtained with the AERF (1.95 mL/g) was still low when compared with that of wheat bread (6 mL/g). The crust and crumb colors and the texture (hardness ¼ 173 g; chewiness ¼ 90.5 and fracturability ¼ 178) presented results similar to those of wheat bread and better than other GFB found in the literature. When analyzed by PCA the AERF obtained at 150 oC–0.5 mol /L lactic acid, showed the best results for the GFB obtained. IR spectroscopy showed that no bands were found for esters (1740/cm) in the AERFs, which could indicate that no new bonds were formed between the rice flour and the lactic acid.

Keywords: Gluten-free, bread, Thermoplastic extrusion, Acid modification, Rice flour

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A New α-Pyrone Derivative, 6-[(E)-Hept-1-enyl]-α-pyrone, with Tyrosinase Inhibitory Activity from a Marine Isolate of the Fungus Botrytis

Abstract

Microorganisms such as bacteria, fungi, and blue-green algae have proven to be a rich source of new biologically active secondary metabolites.1 Marine microorganisms, particularly marine fungi, have recently drawn much attention as an important source of biologically active secondary metabolites. 2 Among marine fungi, those living in association with marine algae are promising sources of novel natural products due to their unique ecological niche. The association between algae and fungi appears to be highly developed since nearly one-third of all higher marine fungi described are namely algicolous or algae-associated organisms.3 Recently, marine-derived fungi have yielded unique biologically active metabolites, such as myrothenones,4 gliotoxin derivatives,5 and asperflavin ribofuranoside,6 suggesting that these organisms would be valuable producers of potential therapeutic agents.

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Oxaloacetate Hydrolase, the C–C Bond Lyase of Oxalate Secreting Fungi

Abstract

Oxalate secretion by fungi is known to be associated with fungal pathogenesis. In addition, oxalate toxicity is a concern for the commercial application of fungi in the food and drug industries. Although oxalate is generated through several different biochemical pathways, oxaloacetate acetylhydrolase (OAH)- catalyzed hydrolytic cleavage of oxaloacetate appears to be an especially important route. Below, we report the cloning of theBotrytis cinerea oahA gene and the demonstration that the disruption of this gene results in the loss of oxalate formation. In addition, through complementation we have shown that the intact B. cinerea oahA gene restores oxalate production in an Aspergillus niger mutant strain, lacking a functional oahA gene. These observations clearly indicate that oxalate  production in A. niger and B. cinerea is solely dependent on the hydrolytic cleavage of oxaloacetate catalyzed by OAH. In addition, the B. cinera oahA gene was overexpressed in Escherichia coli and the purified OAH was used to define catalytic efficiency, substrate specificity, and metal ion activation. These results are reported along with the discovery of the mechanism-based, tight binding OAH inhibitor 3,3-difluorooxaloacetate (Ki 68 nM). Finally, we propose that cellular uptake of this inhibitor could reduce oxalate production.

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Boty, a Long-Terminal-Repeat Retroelement in the Phytopathogenic Fungus Botrytis Cinerea

 Abstract

 

The phytopathogenic fungus Botrytis cinerea can infect an extremely wide range of host plants (tomato, grapevine, strawberry, and flax) without apparent specialization. While studying genetic diversity in this fungus, we found an element which is present in multiple copies and dispersed throughout the genome of some of its isolates. DNA sequence analysis revealed that the element contained direct, long-terminal repeats (LTRs) of 596 bp whose features were characteristic of retroviral and retrotransposon LTRs. Within the element, we identified an open reading frame with sequences homologous to the reverse transcriptase and RNase H domains of retroelement pol genes. We concluded that the element we had identified was a retroelement and named it Boty. By comparing its open reading frame with sequences from other retroelements, we found that Boty is related to the gypsy family of retrotransposons. Boty was present in numerous strains isolated from grapes and tomatoes but not in isolates from lentils. We propose that Boty-containing and Boty-deficient groups represent two lineages in the population of B. cinerea.

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Pengembangan Sensor Kimia Berbasis Reagen Kering Menggunakan TAN [1-(2-Thiazolilazo)-2-Naftol]Untuk Penentuan Ion Kobalt(II) Dalam Sampel Air

Abstract

Telah dikembangkan metode analisis dengan menggunakan reagen kering TAN untuk penentuan ion kobalt (II) dalam sampel air. dalam penelitian ini juga dilakukan analisis ion kobalt (II) dengan menggunakan reagen cair TAN sebagai pembanding dengan metode reagen kering TAN. Hasil penelitian dengan metode reagen cair TAN terjadi pada panjang gelombang maksimum 490 nm dan pH optimum 6. Nilai Batas deteksi yang diperoleh dalam analisis ion kobalt (II) dengan reagen cair TAN ini adalah sebesar 1,955 x 10-6 M (0,115 ppm) dan nilai sensitivitasnya sebesar 1,023 x 10-5 M (0,603 ppm). Analisis ion kobalt (II) dengan reagen cair TAN ini mempunyai logaritmik linear range antara 3,39 x 10-6M (0,2 ppm) dan 3,40 x 10-5M (2 ppm) serta nilai reprodusibilitas yang cukup baik yaitu 1,024 %. Ion-ion logam berat lain yang cukup memberikan pengaruh terhadap analisis ion kobalt (II) dengan reagen cair TAN berturutturut antara lain: nikel (II) > kadmium (II) > timbal (II) > seng (II) >merkuri (II). Sebaliknya Analisis ion kobalt (II) dengan menggunakan reagen kering TAN terjadi pada panjang gelombang maksimum 652 nm dan pH optimum 7 serta nilai batas deteksi sebesar 1,779 x 10-5M (1,04 ppm). Nilai sensitivitas yang diperoleh dalam penelitian ini adalah 7,13 x 10-7M (0,042 ppm) dengan nilai reprodusibilitas sebesar 44,93%. Nilai logaritmik linear range yang diperoleh dengan metode reagen kering TAN ini antara 1,018 x 10--5M (0,6 ppm) dan 3,40 x 10-5M (2 ppm). Ion-ion logam berat lainnya yang cukup memberikan pengaruh antara lain nikel (II) > tembaga (II) > seng (II) > timbal(II). Analisis ion kobalt (II) dengan menggunakan reagen kering TAN ini mempunyai tingkat sensitivitas yang lebih baik bila dibandingkan dengan metode reagen cair TAN.

Keyword : [1-(2-thiazolilazo)-2-naftol](TAN), kobalt (II), reagen kering, reagen cair dan metode spektrofotometri.

 

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Effects of pH and plant source on lignocellulose biodegradation rates in two wetland ecosystems, the Okefenokee Swamp and a Georgia salt marsh

Abstract

 

The microbial mineralization of synthetic [ L4C]lignin, specifically radiolabeled [ 14C-ligninl- lignocellulose and [ L4C-polysaccharide]-lignocellulose from a variety of aquatic herbaceous and woody plants was investigated in water and sediment from a salt marsh on Sapelo Island, Georgia, and from the Okefenokee Swamp, an acidic peat-forming freshwater swamp in southern Georgia. Rates of microbial degradation of lignocellulose were depressed in the Okefenokee relative to those in the salt marsh. About 50% of the difference in mineralization rates was attributable to the low ambient pH (3.9) of Okefenokee water relative to the pH of salt marsh water (pH 7.1). Rates of mineralization of the lignin component of lignocellulose were only minimally affected within the range of pH 4-8, whereas mineralization of the polysaccharide component increased severalfold with increasing pH. Differences in the biodegradability of the various lignocelluloses were also observed; lignocelluloses from herbaceous plants were mineralized several times faster than lignocellulose from wood.

 

Keyword : pH, lignocellulose biodegradation, Okefenokee Swamp, Georgia salt marsh

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ANALISA SENYAWA GOLONGAN FLAVONOID HERBA TEMPUYUNG (Sonchus arvensis L.)

Abstrak

Tempuyung (Sonchus arvensis) dari suku asteraceae merupakan salah satu jenis tanaman yang memiliki beberapa golongan senyawa flavonoid. Telah dilakukan isolasi senyawa golongan flavonoid terhadap ekstrak methanol herba tempuyung kering menggunakan kromatografi kertas dengan eluen n-butanol-asam asetat-air (4:1:5). Analisa dilakukan terhadap ercak yang diperoleh menggunakan metoda spektrofotometeri UV-vis dengan bantuan pereaksi geser natrium hidroksida, alumunium (III) klorida, natrium asetat dan asam borat. Hasil analisa menunjukkan bahwa senyawa flavonoid yang diperoleh termasuk dalam golongan flavon tersubstitusi yaitu 7,4’-hidroksi flavon.

Kata Kunci : Tempuyung (Sonchus arvensis), Flavonoid, Kromatografi kertas, pereaksi geser.

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Penentuan Kadar Kesadahan Air dengan Metode Titrasi EDTA

Abstrak

Semua makhluk hidup di bumi ini butuh air. Air merupakan pelarut yang sangat baik, sehingga di alam umumnya berada dalam keadaan tidak murni. Air alam mengandung berbagai jenis zat, baik yang larut maupun yang tidak larut serta mengandung mikroorganisme. Jika kandungan bahan-bahan dalam air tersebut tidak mengganggu kesehatan, air dianggap bersih dan layak untuk diminum, air dikatakan tercemar jika terdapat gangguan terhadap kualitas air sehingga air tersebut tidak dapat digunakan untuk tujuan penggunaannya. Pencemaran air dapat terjadi karena masuknya makhluk hidup, zat, dan energi terdalam air oleh kegiatan manusia. Keadaan itu dapat menurunkan kualitas air sampai ke tingkat tertentu dan membuat air tidak berfungsi lagi sesuai dengan tujuan penggunaannya.

Air adalah pelarut yang baik, sehingga dapat melarutkan zat-zat dari batu-batuan yang berkontak dengannya. Bahan-bahan mineral yang dapat terkandung dalam air karena kontaknya dengan batu-batuan tersebut antara lain: CaCO3, MgCO3, CaSO4, MgSO4, NaCl, Na2SO4, SiO2 dan sebagainya. Dimana air yang banyak mengandung ion-ion kalsium dan magnesium dikenal sebagai air sadah. Air sadah adalah air yang di dalamnya terlarut garam-garam kalsium dan magnesium air sadah tidak baik untuk mencuci karena ion-ion Ca2+ dan Mg2+ akan berikatan dengan sisa asam karbohidrat pada sabun dan membentuk endapan sehingga sabun tidak berbuih. Senyawa-senyawa kalsium dan magnesium ini relatif sukar larut dalam air, sehingga senyawa-senyawa ini cenderung untuk memisah dari larutan dalam bentuk endapan atau precipitation yang kemudian melekat pada logam (wadah) dan menjadi keras sehingga mengakibatkan timbulnya kerak (Bintoro, 2008).
 

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Metode Statistik dan Aplikasinya dengan MINITAB dan Excel

Judul         : Metode Statistik dan aplikasinya dengan MINITAB dan Excel
Pengarang : Dadan Kusnandar, PhD
Penerbit    : Madyan Press, Yogyakarta

Abstrak

 

Sebagai suatu disiplin ilmu, statistik pada mulanya berkembang karena kebutuhan pihak pemerintah atau penguasa untuk mengumpulkan informasi yang berkaitan dengan data kependudukan. Sejarah menunjukkan bahwa pengumpulan data telah dilakukan sejak berabad-abad yang lalu. Pada masa kejayaan Kekaisaran Yunani dan Romawi pengumpulan informasi dilakukan terutama sekali untuk keperluan penentuan pajak dan ketentuan yang berkaitan dengan wajib dinas militer. Demikian juga pemerintah Belanda pada masa penjajahannya di Indonesia telah mengumpulkan berbagai informasi tentang Indonesia, tidak hanya tentang kependudukan saja tetapi juga berbagai informasi lainnya, seperti informasi tentang flora dan fauna Indonesia, sosial, budaya, dan sebagainya. Saat ini, semua negara di dunia telah melakukan berbagai jenis sensus secara periodik, paling tidak setiap sepuluh tahunan, demi untuk mendapatkan berbagai informasi yang akurat dan up to date. Istilah-istilah seperti sensus kependudukan, sensus pertanian, dan sensus ekonomi, sudah bukan merupakan istilah yang asing lagi bagi telinga kita.

Keyword : Metode Statistik, Aplikasi Minitab, Excel

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