Bioprinting of a Cell-Laden Conductive Hydrogel Composite

Seawater desalination is becoming a crucial intervention for mitigating water shortage in numerous Middle East countries. Desalination technology is associated with various technological challenges that should be resolved to maintain plant sustainability and performance. For instance, seawater hardness is recognized as a challenge for recent large scale desalination plants. Optional technologies including chemical treatment, adsorption and membrane filtration have been developed for hardness removal and recovery of Ca and Mg. This paper addresses the development and application of a new conductive polymeric hydrogel composite exhibiting electrically tunable characteristics. A comprehensive review on the preparation of conductive hydrogel and its application for water treatment is first presented. The newly developed hydrogel composite comprises treated zeolite, polyacrylate, polyaniline, hydrolyzed polyacrylamide and special processing aids. The characteristics of the composite have been determined via scanning electron microscopy, Fourier transform infrared spectroscopy and electric conductivity measurements in addition to swelling ratio. Impact of composition and processing conditions on conventional and electrochemically enhanced adsorption experiments have been presented and analyzed. Electro-regeneration has been also explored. The promising features of this hydrogel in composite are elucidated by the removal and recovery of hardness causing elements in simulated seawater and brines. It is concluded that the developed hydrogel is initially qualified for upstream seawater softening. Additional endeavors are still needed for downstream brine management to overcome apparent osmotic effects.

Download Full-text

Effect of Niacin on Mitochondria of Allium Cepa Root Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100060404 ◽

1967 ◽

Vol 25 ◽

pp. 78-79

Author(s):

M. Arif Hayat

Keyword(s):

Nicotinamide Adenine Dinucleotide ◽

Hydrogen Transfer ◽

Nicotinamide Adenine Dinucleotide Phosphate ◽

Nicotinamide Adenine ◽

Root Tips ◽

Root Cells ◽

Transfer Processes ◽

Standard Procedures ◽

A Cell ◽

Critical Interest

Although it is recognized that niacin (pyridine-3-carboxylic acid), incorporated as the amide in nicotinamide adenine dinucleotide (NAD) or in nicotinamide adenine dinucleotide phosphate (NADP), is a cofactor in hydrogen transfer in numerous enzyme reactions in all organisms studied, virtually no information is available on the effect of this vitamin on a cell at the submicroscopic level. Since mitochondria act as sites for many hydrogen transfer processes, the possible response of mitochondria to niacin treatment is, therefore, of critical interest.Onion bulbs were placed on vials filled with double distilled water in the dark at 25°C. After two days the bulbs and newly developed root system were transferred to vials containing 0.1% niacin. Root tips were collected at ¼, ½, 1, 2, 4, and 8 hr. intervals after treatment. The tissues were fixed in glutaraldehyde-OsO4 as well as in 2% KMnO4 according to standard procedures. In both cases, the tissues were dehydrated in an acetone series and embedded in Reynolds' lead citrate for 3-10 minutes.

Download Full-text

Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084120 ◽

1978 ◽

Vol 36 (2) ◽

pp. 650-651

Author(s):

Raul I. Garcia ◽

Evelyn A. Flynn ◽

George Szabo

Keyword(s):

Direct Injection ◽

Skin Pigmentation ◽

Freeze Fracture ◽

Pigment Granule ◽

Time Lapse ◽

Ultrastructural Level ◽

Lanthanum Tracer ◽

A Cell

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

Download Full-text

Dendritic cells of the human epidermis: immuno-electron microscopic studies of la antigen reactivity

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084090 ◽

1978 ◽

Vol 36 (2) ◽

pp. 644-645

Author(s):

G. Rowden ◽

M. G. Lewis ◽

T. M. Phillips

Keyword(s):

Dendritic Cells ◽

Langerhans Cells ◽

Cell Types ◽

Cell Type ◽

Electron Microscopic ◽

La Antigen ◽

Microscopic Studies ◽

A Cell ◽

C3 Receptors ◽

Antigen Reactivity

Langerhans cells of mammalian stratified squamous epithelial have proven to be an enigma since their discovery in 1868. These dendritic suprabasal cells have been considered as related to melanocytes either as effete cells, or as post divisional products. Although grafting experiments seemed to demonstrate the independence of the cell types, much confusion still exists. The presence in the epidermis of a cell type with morphological features seemingly shared by melanocytes and Langerhans cells has been especially troublesome. This so called "indeterminate", or " -dendritic cell" lacks both Langerhans cells granules and melanosomes, yet it is clearly not a keratinocyte. Suggestions have been made that it is related to either Langerhans cells or melanocyte. Recent studies have unequivocally demonstrated that Langerhans cells are independent cells with immune function. They display Fc and C3 receptors on their surface as well as la (immune region associated) antigens.

Download Full-text

Presence of antibody in virus-infected brain cells of SSPE ferrets

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077591 ◽

1983 ◽

Vol 41 ◽

pp. 804-805

Author(s):

Hannah R. Brown ◽

Tammy L. Donato ◽

Halldor Thormar

Keyword(s):

Measles Virus ◽

Plasma Cells ◽

Subacute Sclerosing Panencephalitis ◽

Protein A ◽

Neutralizing Antibody ◽

Brain Cells ◽

Antibody Titers ◽

A Cell ◽

The Central Nervous System ◽

The Brain

Measles virus specific immunoglobulin G (IgG) has been found in the brains of patients with subacute sclerosing panencephalitis (SSPE), a slowly progressing disease of the central nervous system (CNS) in children. IgG/albumin ratios indicate that the antibodies are synthesized within the CNS. Using the ferret as an animal model to study the disease, we have been attempting to localize the Ig's in the brains of animals inoculated with a cell associated strain of SSPE. In an earlier report, preliminary results using Protein A conjugated to horseradish peroxidase (PrAPx) (Dynatech Diagnostics Inc., South Windham, ME.) to detect antibodies revealed the presence of immunoglobulin mainly in antibody-producing plasma cells in inflammatory lesions and not in infected brain cells.In the present experiment we studied the brain of an SSPE ferret with neutralizing antibody titers of 1:1024 in serum and 1:512 in CSF at time of sacrifice 7 months after i.c. inoculation with SSPE measles virus-infected cells. The animal was perfused with saline and portions of the brain and spinal cord were immersed in periodate-lysine-paraformaldehyde (P-L-P) fixative. The ferret was not perfused with fixative because parts of the brain were used for virus isolation.

Download Full-text