Plants of interest

How to deal with the pests that attack plants under cultivation is a continuing challenge to the food and agricultural production system. Natural resistance or tolerance to pests has proven to be one of the safest and least costly ways to protect plants. As we identify the specific plant components involved and their actions, it will be easier to incorporate the capacity to produce the desired chemical into the plant of Interest. There is the further possibility to identify additional natural chemicals that may be useful as pest control materials. The latter might be through the use of natural products or it might be products of industrial synthesis patterned after the natural products. It is clear that allelochemicals are involved in these complex processes and they hold promise for even a greater role. 

Table 1 lists some allelopathlc plants of interest to foresters, together with the classes of toxic compounds produced and examples of species they are reported to suppress. The list is not exhaustive many species that may be allelopathlc have not been studied in depth. One easily observed effect—though sometimes difficult to distinguish from effects of competition—is the exclusion of shrubs, herbs, and other trees from beneath the crowns of particular tree species. 

Because of the important nutritive attributes of the eleven elements specifically listed above, most of the analytical effort in the past few decades has been directed toward the determination of the concentrations of some or all of these elements in foods and plants of interest. However, there can also he justifiable interest in what other elements are present. Some elements are, of course, toxic even at low concentrations. Some elements may have as yet undiscovered nutritive value. Beyond these considerations it may he important to know if there are elements whose concentration depends on, and thus may be indicative of, the geographical locale in which the plants were grown. If such elements are present and if their concentrations can he measured, this information, perhaps, could be used for "fingerprinting" or characterizing the juice as to its origin. 

Example of the bioassay-derived fractionation and isolation of anti-HIV compounds from a typical high priority plant of interest. 

In this second part, we will test a number of specimens of the same species in each of several locations for variation of cyanogenesis in a population. We will use Trifolium repens (white clover) or Lotus comiculatus (birdsfoot trefoil). To collect the plants in a systematic fashion, we lay out a grid. Sticks mark the ends of rows (transects) on a lawn or in a field. We start with one plant, then pick one plant 1 m along the transect, and so forth. If no plant of interest exists at that point, the closest plant is chosen, and the next one will be 1 m from that, and so on. 

Laboratory diagnosis. Toxic prittoiples in plarrts are often r t lietected by routinely available tests in diagnostic orch nical laboratories. R is necessary to know the availability of confirmatory chemical testing for important plants of interest in a specific veterinary practice. 

In 2006, EcoBiotics Limited, an Australian company that specializes in the discovery and preclinical development of small-molecule drug leads from the tropical rainforests of Australia and Melanesia, approached me to undertake a total synthesis of EBC-23 (1) (Figure 1). EBC-23 (1) had been isolated from Cinnamomum laubatii (family Lauraceae) in the rainforest in northern Queensland, Australia, after the latter was identified by Dr. Paul Reddell (CSO, EcoBiotics) as a plant of interest. The reason for the synthesis request was that a screening program had identified 1 as a growth inhibitor of the androgen-independent prostate tumor cell line DU 145, which was reinforced... 

In summary, phytovolatilization from both leaves and stems has been reported. However, the importance of phytovolatilization depends on both the properties of the chemical contaminant and the plant of interest. While phytovolatilization has been incorporated into several mechanistic plant uptake models such as that of Trapp (2007), additional experimental data collected under a variety of field settings are needed before the general significance of this process can be adequately assessed. 

Finally, preliminary diagnostic evaluation criteria, based on preventive identification of critical areas of interest on the monitored item, spatial concentration of localized AE events as compared with average AE event density and evolution of local event concentration vs time and/or plant parameters, have been worked out and submitted to extensive testing under real operation conditions. Work on this very critical issue is still to be consohdated. 

Polysaccharides are macromolecules which make up a large part of the bulk of the vegetable kingdom. Cellulose and starch are, respectively, the first and second most abundant organic compounds in plants. The former is present in leaves and grasses the latter in fruits, stems, and roots. Because of their abundance in nature and because of contemporary interest in renewable resources, there is a great deal of interest in these compounds. Both cellulose and starch are hydrolyzed by acids to D-glucose, the repeat unit in both polymer chains. 

Creep of Thick-walled Cylinders. The design of relatively thick-walled pressure vessels for operation at elevated temperatures where creep caimot be ignored is of interest to the oil, chemical, and power industries. In steam power plants, pressures of 35 MPa (5000 psi) and 650°C are used. Quart2 crystals are grown hydrothermaHy, using a batch process, in vessels operating at a temperature of 340—400°C and a pressure of 170 MPa (25,000 psi). In general, in the chemical industry creep is not a problem provided the wall temperature of vessels made of Ni—Cr—Mo steel is below 350°C. 

A number of papers have appeared on the removal of heavy metals in the effluents of dyestuff and textile mill plants. The methods used were coagulation (320—324), polymeric adsorption (325), ultrafiltration (326,327), carbon adsorption (328,329), electrochemical (330), and incineration and landfiU (331). Of interest is the removal of these heavy metals, especiaUy copper by chelation using trimercaptotria2ine (332) and reactive dyed jute or sawdust (333). 

A fourth method of computing depreciation (now seldom used) is the sinking-fund method. In this method, the annual depreciation A is the same for each year of the life of the equipment or plant. The series of equal amounts of depreciation Aq, invested at a fractional interest rate i and made at the end of each year over the life of the equipment or plant of s years, is used to build up a future sum of money equal to (Cpc S). This last is the fixed-capital cost of the equipment or plant minus its salvage or scrap value and is the total amount of depreciation during its useful life. The equation relating i Fc S) and Ao is simply the annual cost or payment equation, written either as... 

In the sinking-fund method of depreciation, the effect of interest is to make the annual decrease of the book value of the equipment or plant less in the early than in the later years with consequent higher tax due in the earlier years when recovery of the capital is most important. 

A development of interest to the chemical industiy is the tubular precipitator of reinforced-plastic construction (Wanner, Gas Cleaning Plant after T1O2 Rotary Kilns, technical bulletin, Lurgi Corp., Frankfurt, Germany, 1971). Tubes made of polyvinyl chloride plastic are reinforced on the outside with polyester-fiber glass. The use of modern economical materials of construction to replace high-maintenance materials such as lead has been long awaited for corrosive applications. 

Ion probes. Determining the level of ions in solution also helps to control corrosion. An increase in concentration of specific ions can contribute to scale formation, which can lead to a corrosion-related failure. Ion-selective elec trode measurements can be included, just as pH measurements can, along with other more typical corrosion measurements. Especially in a complete monitoring system, this can add information about the effect of these ions on the material of interest at the process plant conditions. 

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