The Duodenum

The duodenum is the first part of the small intestine that arises from the embryologic foregut and midgut. With maturation, it lies mostly retroperitoneal and is intimately associated with nearby structures such as the pancreas, hepatoduodenal ligament, and transverse colon mesentery. It is well vascularized with a rich lymphatic network and supports digestive, absorptive, immune, and endocrine functions. The duodenum receives food bolus from the stomach and releases various hormones important for regulating motility and gastric acid secretion. In the duodenum, food content mixes with bile and pancreatic enzymes to continue digestion of and initiate absorption for fats, carbohydrates, proteins, and vitamins and minerals. The duodenum experiences substantial exposure to the external environment and therefore contains an extensive immune barrier, including mucosa-associated lymphoid tissue. Additionally, there is a significant neuroendocrine network within the duodenum and small intestine that possesses a variety of endocrine functions, including regulation of acid secretion, motility, pancreatic function, bile flow, and mucosal cell growth. These enterochromaffin cells are the source duodenal neuroendocrine tumors (carcinoid) and can be classified according to subtype or grade. The duodenum is a diverse component of the small intestine that is uniquely suited to its numerous functions. Key words: absorption, acid secretion, anatomy, digestion, duodenum, intestinal immune system, microstructure, motility, mucosa-associated lymphoid tissue, neuroendocrine

The Duodenum

The duodenum is the first part of the small intestine that arises from the embryologic foregut and midgut. With maturation, it lies mostly retroperitoneal and is intimately associated with nearby structures such as the pancreas, hepatoduodenal ligament, and transverse colon mesentery. It is well vascularized with a rich lymphatic network and supports digestive, absorptive, immune, and endocrine functions. The duodenum receives food bolus from the stomach and releases various hormones important for regulating motility and gastric acid secretion. In the duodenum, food content mixes with bile and pancreatic enzymes to continue digestion of and initiate absorption for fats, carbohydrates, proteins, and vitamins and minerals. The duodenum experiences substantial exposure to the external environment and therefore contains an extensive immune barrier, including mucosa-associated lymphoid tissue. Additionally, there is a significant neuroendocrine network within the duodenum and small intestine that possesses a variety of endocrine functions, including regulation of acid secretion, motility, pancreatic function, bile flow, and mucosal cell growth. These enterochromaffin cells are the source duodenal neuroendocrine tumors (carcinoid) and can be classified according to subtype or grade. The duodenum is a diverse component of the small intestine that is uniquely suited to its numerous functions. Key words: absorption, acid secretion, anatomy, digestion, duodenum, intestinal immune system, microstructure, motility, mucosa-associated lymphoid tissue, neuroendocrine

PERBANDINGAN PENYERAPAN UNSUR HARA OLEH TANAMAN PADI (Oryza Sativa.L ) DENGAN TANAMAN KACANG PANJANG ( Vigna sinensis ) YANG DITANAM PADA TANAH MENGGUNAKAN ICP-MS

ABSTRACT Comparative studies on nutrient uptake ability of rice plants (Oryza Sativa.L) that represent groups of plants dicotyledonous with long beans (Vigna sinensis) representative of the group of plants monocotyledonous have been conducted. The study was conducted on a community farm located in the Village of Sungai Sapih Padang, at plants are used as the sample is sokan varieties. The root of leaves and fruit as well as beans, the same parts are used as sample.Morphological observations of roots, leaves and fruit using the SEM showed the difference between the rice and beans. While the homogenity for fruit rice and beans especially almost the same. The results of nutrient measurements performed by ICP - MS, elemental carbon is the largest percentage of nutrients in the two plants in average above 50% in all parts of the plant. The percentage of Ca, Mg and N elements in the leaves of beans is higher than in the rice leaves, otherwise the percentage of Si element is higher in the rice plants. Key words: absorption, nutrients, Oryza sativa, Vigna sinensis, ICP-MS

A New Method to Measure the Absorption Coefficient Based on the Sound Pressure Delaying

Absorption coefficient is an important parameter of the absorption function of the absorption material. Traditional measurement methods of absorption coefficient are standing wave tube and reverberation which have some shortcomings. In this paper, phase of the sound pressure measured by two equal distance microphones placed in the front of the absorption material is delayed in order to attain the absorption coefficient. At the last, an experiment for one absorption material is carried out, the experiment results compare with the results of the other methods above mentioned that denotes that the theory is correct and practicable. Key words: absorption material standing wave reverberation time delaying

Absorption spectroscopy of (Ind)Ni(PPh3)X (Ind = indenyl, 1-Me-indenyl; X = Cl, Br, Me) and M(Ind)2 (M = Ni, Ru; Ind = indenyl)

The electronic structures of two types of transition metal indenyl complexes have been studied. The first type, a series of (Ind)Ni(PPh3)X compounds (Ind = indenyl, 1-Me-indenyl; X = Cl, Br, Me) was investigated by absorption spectroscopy and Extended Hückel Molecular Orbital calculations. The energy differences between calculated levels are in good agreement with experimental band positions. For example, the lowest energy singlet–singlet band maximum for (Ind)Ni(PPh3)Cl is at 19 500 cm−1 and the calculated HOMO–LUMO difference is 19 817 cm−1. For X = Me, the calculated energy difference increases to 21 930 cm−1 and the corresponding absorption band is at 22 500 cm−1. The influence of the metal–ligand interactions on the molecular orbitals is discussed. The second category of indenyls, the bis(indenyl) compounds of Ni and Ru, show absorption spectra that are markedly different from those of nickelocene and ruthenocene. For example, in comparison to nickelocene, the first absorption band of Ni(Ind)2 is 5700 cm−1 higher in energy and is more intense by two orders of magnitude; in contrast, the first absorption maximum of Ru(Ind)2 is 6600 cm−1 lower in energy than observed for ruthenocene. The characteristics and relaxation dynamics of the lowest energy excited states are discussed. Key words: absorption spectroscopy, indenyl, nickel, ruthenium, EHMO analysis.