Chemical Engineering

Low‐protein content natural rubber latex was produced by using a nonionic surfactant‐polyethylene glycol (PEG). Extractable protein content of natural rubber latex was found to decrease with PEG treatment and reduction increased with increase in the molecular weight of PEG. The low‐protein latex samples were characterized by tensile testing, Fourier transform infrared and thermogravimetric analysis. The results have shown 35% reduction in the extractable protein content, without any compromise on the mechanical properties of the latex; however, thermal stability of low‐protein latex was found to be reduced marginally with PEG treatment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Surgical gloves are intended as a barrier between the patient and the healthcare worker. This paper deals with the study conducted on natural rubber based surgical gloves incorporated with Nanosilica. Nanosilica was incorporated into NR latex and then compounded with regular cure ingredients typical of a glove formulation. The compounded latex was then dipped in suitable moulds of ceramic material and processed by conventional method in a continuous chain surgical gloves dipping line. All the parameters of a glove production line were simulated in the production of surgical gloves, used in the study. The water soluble residual protein content and the physical properties of the glove were studied.. Presence of water soluble residual proteins sensitizes the human body and hence it's presence is an issue in the manufacture of Surgical gloves. It was observed during the study that there was considerable reduction in protein content on addition of nanosilica but the physical properties of the glove remained unaffected. A dosage of 0.1 to 0.5 phr of Nanosilica on rubber was used and the properties were found to be optimum at 0.2 phr levels. The study revealed the possibility of reduction in protein content by incorporating Nanosilica.

An immunoaffinity process based on monoclonal antibody (MAb) to factor IX (FIX) has been developed. Initially, vitamin-K-dependent proteins from cryoprecipitate-poor plasma are isolated on DEAE-Sephadex. The eluate is applied to an immunoaffinity column that utilizes a divalent metal-ion-dependent MAb directed against FIX. After washing the column with high salt in the presence of magnesium ion, the FIX is eluted using a citrate-or EDTA-containing buffer. Coagulation assays and Western blots show no detectable amounts of any contaminating proteins. Purity of the FIX product is established using reduced and nonreduced Coomassie-stanined SDS-PAGE and HPLC. The N-terminal20 amino acids of the single peak of the HPLC were shown to be identical to those reported for FIX. The process shows no detectable leakage of monoclonal antibodies (MAb), efficient utilization of MAb, and provides yields greater than 95%. The use of solvenddetergent treatment as a potential viral inactivation method is incorporated in the process. Studies with tritiated Triton X-100 indicate that the detergent can be washed out of the MAb column so that less than lppm (total) Triton X-100 coelutes with the FIX.

We report the development of a semi-continuous method for preparation of factor IX complex from human plasma using ion exchange resins. Traditionally, stirred batch adsorption has been used due to the high pressure drops and low flow rates associated with soft gels in packed columns. Batch methods, however, typically involve higher labor costs and are more cumbersome in process environments. In the semi-continuous process, cryo-supernatant plasma is pumped through a 'stirred column' containing the resin. At both lab and pilot scale, higher recoveries of factor IX (FIX) were obtained at decreased total process times, compared to batch adsorption. A residence time of 15 min was found to be sufficient for capture of 95% of the FIX in the starting plasma. In the pilot plant, 550liters of plasma was passed through a 50-liter column containing 8.5 liters of resin, yielding a 68% recovery of FIX. The results suggest that the recovery of FIX depends on the mode of contact (batch, continuous or packed column) between plasma and resin.

A radial flow hollow fiber bioreactor has been developed that maximizes the utilization offibersurface for cell growth while eliminating nutrient and metabolic gradients inherent in conventional hollow fiber cartridges. The reactor consists of a central flow distributor tube surrounded by an annular bed of hollow fibers. The central flow distributor tube ensures an axially uniform radial convective flow of nutrients across the fiber bed. Cells attach and proliferate on the outer surface of the fibers.

It has been cited in the literature on hollow fiber systems that pressure gradients persist, and the transmembrane flux of the hollow fiber system is dependent on the pattern of the pressure gradients. The pattern can be used to its advantage in immobilized enzyme systems. However, with immobilized living cell systems, the pressure gradients lead to a nonuniform environment within the hollow fiber cartridge and not necessarily favorable results. This article provides pertinent pressure-drop data on hollow fiber cartridges which are in flow configurations typical of immobilized cell culture work. The results illuminate operational problems that may arise in the culture of either anchorage dependent or independent cells. Possible solutions with crossflow systems are suggested.

A model for radial flow mammalian cell culture has been developed. Two situations, one with permeable hollow fibers and the other with a porous matrix in the annulus, were considered. The hollow fibers were modeled as continuously distributed sinks. Numerical solutions are presented for the complete model as well as limiting analytical solutions. The analysis identified the importance of various kinetic, transport, and design dimensionless groups for maintenance of radial flow cell culture systems under uniform conditions. The important design parameter was the depth of the bed and the important operating parameter was a modified Damkohler number, both of which should be maintained low for gradient free systems. Dispersion was included in the analysis but substrate consumption was relatively independent of dispersion. Preliminary separation of a low-and high-molecular-weight product was also modeled, and shown to be strongly dependent on the permeability of the fibers, as well as the aspect ratio and the magnitude of the transmembrane flux.

A murine hybridoma (455) was cultured in four different serum free media formulations, and a newborn calf serum supplemented medium was used as a basis of comparison. The serum supplemented medium supports a higher cell growth rate and results in a higher IgG titer. However, the antibody secretion rate on a per cell basis is higher in the serum free media, indicating that serum could be inhibitory to antibody secretion. The results identify the possibility of at least eliminating serum during the monoclonal antibody production phase.

A dual circuit bioreactor is developed; it consists of two intercalated-spiral sets of hollow fibers with alternated dead-ends. The construction is relatively simple, but guarantees uniform distribution of the'arterial'and'venous'circuits. Data are presented to illustrate the ability of the bioreactor to culture a human lymphoblastoid B-cell line.

A new, virus-inactivated, media supplement from human plasma (GEMS) has been developed which maintains hybridoma ceils at a low growth rate. The rate of antibody production per ceil by hybridoma cells growing in the presence of GEMS is at least equivalent to the rate of antibody production by the same cell lines growing in fetal bovine serum.

A microbial consortia was isolated from trinitrotoluene (TNT) contaminated soil and cultured in media supplemented with structurally similar (aromatic) or non-aromatic cosubstrates and TNT to examine their impact on cometabolic TNT biotransformation. A microbial inoculum with 105 CFU/ml with TNT concentrations of 5, 10, 30 and 50 ppm in separate triplicate cultures revealed maximum TNT biotransformations of 23, 21, 9 and 3%, respectively, after 9 days, A larger inoculum (107CFU/ml) resulted in transformation of TNT concentrations of 8, 15, 22 and 30 ppm by 71, 54, 50 and 38%, respectively. Cultures supplemented with benzene, nitrobenzene or toluene revealed no enhancement of TNT biotransformation rates or extents over those in culture with TNT as sole carbon source. With glucose and citric acid at 30 mg/1, TNT biotransformations of 56 and 51%, respectively, were obtained.

This paper focuses on the development and implementation of an appropriate technology for sourcing, collection, treatment, storage, conservation and management of water, focused on public health improvement. Potable water availability and sanitary treatment and disposal of wastes are two critical prerequisites for the improvement of public health, and for the development and maintenance of a viable and sustainable public health infrastructure. Public health development indices will only show improvement with diverse appropriate technology development and implementation for water treatment and availability, and maintenance of adequate water supplies. This paper discusses rainwater harvesting and water harvesting as appropriate water collection technologies, highlighting some of the best available technologies and discussing their application in, and pertinence to, productive and sustainable public health efforts.

Indigenous knowledge systems (IKS) comprises knowledge developed within indigenous societies, independent of, and prior to, the advent of the modern scientific knowledge system (MSKS). Examples of IKS such as Ayurveda from India and Acupuncture from China are well known. IK covers diverse areas of importance for society, spanning issues concerned with the quality of life-from agriculture and water to health. The IK resident in India and China have high relevance to rural life, especially given the level of engagement with agricultural and health technologies. The goal is to establish a heuristic whereby IK can be reviewed and evaluated within particular contexts to determine if the IKS can lead to the development of appropriate technology (AT) addressing that need sustainably. Although much work on cataloguing and documenting IKS has been completed in these two countries, a paucity of attention has been paid to the scientific rationale and technological content of these IKS. Evaluation of many indigenous technologies reveal that many of these technologies can be classified as 'appropriate', focused on basic needs of water, sanitation and agriculture, and many have origins in IKS that survived. Thus, IKS must be validated, exploited and integrated into AT innovation and development.

The development across Africa has been piecemeal and uneven, sometimes actually leading to impoverishment and "underdevelopment." Former colonizers and multilateral development agencies have often been the agents of these postcolonial development practices, which focused on facilitation of extraction of wealth, either as material resources or raw agricultural product and export, usually to former colonial era companies. The processing of those natural resources produced immense value-added wealth; however, not much wealth returned to Africa. These development models have been piecemeal, with symptomatic solutions that are Band-Aids, resulting in minimal progress in terms of actual improvement in the quality of life and well-being of citizens. To counter this, it is necessary to shift from linear, mechanistic worldviews to holistic, complex visualizations that are integrated and systemic. This transformation, in understanding and conceptualization through system lenses, makes clear that the unit of development must be ecosystems centered and represent organizational patterns that encompass the whole environment, including human, social, cultural, technological, and economic facets. This new understanding requires comprehensive ecological literacy transitioning from homo-arrogance to biomimicry. Such transformation enables comprehensive solutions that account for interaction among natural, physical, and social phenomena. This chapter describes a development approach, embodied in the Songhai model and conceptualized, developed, and successfully implemented by Godfrey Nzamujo. It captures the essence and reflects a new paradigm, whose core foundational ideas are synergy, symbiosis, collaboration, and complementarity. This new paradigm, as demonstrated by Nzamujo and Songhai, is described as a potentially transformative development model, ensuring sustainability for the future of Africa.

Most conventional introductory courses on environmental engineering are offered as core or electives courses within chemical or civil engineering departments, with the primary focus usually being on the description and analysis of pollutant generation and transport in water, air, and soil. There is a concomitant discussion and analysis of the physical, chemical and biological treatment technologies that have been developed for pollution remediation and control. Scant attention, however, is paid to the social, political, economic, and technological, in short total, environment within which environmental engineering principles and practices, mediated by legal and regulatory forces, gets implemented. In this paper, I discuss the introduction of ethics, environmental policy and environmental regulatory issues into a regular introductory environmental engineering course. This is accomplished by beginning the course with a discussion of environmental ethics, followed by a general introduction to concepts in environmental law, focusing on what have become part of accepted legal practice, or have become evolving legal issues. Within the context of environmental regulations and the evolution of environmental laws, the broad range of situations that fall under the wide brushstroke of environmental justice are reviewed, analyzed and discussed. For engineering students, this is an exciting introduction to the social context of the science and engineering of the environment. Course materials include contemporary and historical readings followed by discussion and analysis, and also include general surveys of data, where applicable and available. Some specific case studies are included as well, time permitting. The material is covered in lecture/discussion mode, which permits the incorporation of brief introductions to environmental technologies and options, many suggested by the students themselves. With such a contextualization of environmental engineering practice, students are better primed for, and more receptive to, an introduction to the principles and technologies of environmental engineering.