Abstract:
Hand sanitizers and methods for producing and using the same are provided. In an embodiment, a hand sanitizer comprises an alkyl monoalcohol at from about 50 to about 95 weight percent, based on the total weight of the hand sanitizer, where the monoalcohol has from 1 to 3 carbon atoms. The hand sanitizer also comprises a glycerin alkyl ether at from about 0.1 to about 5 weight percent, a glycerin alkyl ester at from about 0.1 to about 3 weight percent, an aromatic alcohol at from about 0.1 to about 3 weight percent, and a thickening agent at from about 0.01 to about 0.5 weight percent. All weight percents are based on the total weight of the hand sanitizer.

Description:
TECHNICAL FIELD 
       [0001]    The technical field generally relates to hand sanitizers in the form of a gel and methods to produce and use the same, and more particularly relates to gel-type hand sanitizers with alcohol and an enhanced antimicrobial effect, and methods to produce and use the same. 
       BACKGROUND 
       [0002]    One of the primary methods of reducing the spread of germs and diseases is the use of proper hand care and sanitation. This is especially true in industries or areas where bacterial contamination is particularly problematic, such as health care and food and beverage industries. Hand washing with soap and water is commonly used, but hand sanitizers that do not need to be washed off have become popular as well. The user applies the hand sanitizer onto the hands and spreads it around such that the hand sanitizer contacts most or all of the skin on the hands. Hand sanitizers are available in gels or foams, and many include antimicrobial agents. One such antimicrobial agent is alcohol, and alcohol-based hand sanitizing products are known and in use. Alcohol-based sanitizers can be found in hospitals and other healthcare environments, the workplace, and in everyday home use. Hand sanitizers with alcohol of about 50% or more have a very rapid antimicrobial effect, but the alcohol may not have a persistent antimicrobial effect. Alcohol kills many microbes on contact, but alcohol may evaporate and leave the hands or other surfaces unprotected. Some components may be added to the hand sanitizer to help slow the evaporation of alcohol, but alcohol will still evaporate. Alcohol is very effective against many bacteria, but alcohol is not effective against all microbes. For example, alcohol has limited efficacy against some viruses, such as many noroviruses and the rabies virus. As such, some illnesses may be caused by microbes that survive exposure to alcohol. 
         [0003]    Accordingly, it is desirable to provide hand sanitizers with enhanced antimicrobial efficacy, and methods for producing and using the same. In addition, it is desirable to provide hand sanitizers that provide increased antimicrobial persistence over hand sanitizers using alcohol as the sole antimicrobial ingredient, and methods of producing and using the same. Other desirable features and characteristics of the present embodiment will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention. 
       BRIEF SUMMARY 
       [0004]    Hand sanitizers and methods for producing and using the same are provided. In an embodiment, a hand sanitizer comprises an alkyl monoalcohol at from about 50 to about 95 weight percent, based on the total weight of the hand sanitizer, where the monoalcohol has from 1 to 3 carbon atoms. The hand sanitizer also comprises a glycerin alkyl ether at from about 0.1 to about 5 weight percent, a glycerin alkyl ester at from about 0.1 to about 3 weight percent, an aromatic alcohol at from about 0.1 to about 3 weight percent, and a thickening agent at from about 0.01 to about 0.5 weight percent. All weight percents are based on the total weight of the hand sanitizer. 
         [0005]    In another embodiment, a method is provided for using a hand sanitizer. An effective amount of the hand sanitizer is applied to the hands. The hand sanitizer comprises an alkyl monoalcohol at from about 50 to about 95 weight percent, a glycerin alkyl ether at from about 0.1 to about 5 weight percent, a glycerin alkyl ester at from about 0.1 to about 3 weight percent, an aromatic alcohol at from about 0.1 to about 3 weight percent, and a thickening agent at from about 0.01 to about 0.5 weight percent, where all weight percentages are based on the total weight of the hand sanitizer. The alkyl monoalcohol has from 1 to 3 carbon atoms. 
         [0006]    In yet another embodiment, a method is provided for producing a hand sanitizer. An alkyl monoalcohol is combined with a glycerin alkyl ether, a glycerin alkyl ester, an aromatic alcohol, and a thickening agent. The alkyl monoalcohol is added at from about 50 to about 95 weight percent, the glycerin alkyl ether is added at from about 0.1 to about 5 weight percent, the glycerin alkyl ester is added at from about 0.1 to about 3 weight percent, the aromatic alcohol is added at from about 0.1 to about 3 weight percent, and the thickening agent at from about 0.01 to about 0.5 weight percent, where all weight percentages are based on the total weight of the hand sanitizer. The alkyl monoalcohol has from 1 to 3 carbon atoms. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The present embodiments will hereinafter be described in conjunction with the drawing FIGURE, wherein: 
           [0008]    The FIGURE is a schematic representation of an exemplary embodiment of a hand sanitizer and a method of producing the same. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    The following detailed description is merely exemplary in nature and is not intended to limit the various embodiments of the hand sanitizer and methods of preparing the same, or the application and uses of the hand sanitizers. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description. 
         [0010]    Reference is made to the FIGURE. The various embodiments contemplated herein relate to hand sanitizers  10  with enhanced antimicrobial activity, where “enhanced” antimicrobial activity, as used herein, means antimicrobial activity that is greater than the antimicrobial activity of a hand sanitizer  10  that uses alcohol as the only antimicrobial agent. 
         [0011]    The hand sanitizer  10  includes an alkyl monoalcohol  12  at from about 50 weight percent to about 95 weight percent in an exemplary embodiment, but in alternate embodiments the hand sanitizer  10  may include an alkyl monoalcohol  12  at from about 60 to about 95 weight percent or from about 75 to about 95 weight percent, where the weight percent is based on the total weight of the hand sanitizer  10 . The percentage of all components of the hand sanitizer  10  described herein are weight percent, based on the total weight of the hand sanitizer  10 , unless otherwise specified. Alkyl monoalcohols  12  are a very effective antimicrobial agent when present at concentrations of about 50 weight percent, or about 60 weight percent, or about 75 weight percent or more, and there appears to be little to no genetic mutation that produces microbes that are resistant to the antimicrobial effect of alkyl monoalcohols  12 . Alkyl monoalcohols  12  produce a very rapid antimicrobial effect, and may kill about 99.9 percent of bacteria on a person&#39;s hands within about 30 seconds after application when applied at sufficient concentrations, and higher kill rates may be achieved with longer exposure time. Alkyl monoalcohols  12  kill many bacteria that are resistant to various antibiotics, and alkyl monoalcohols  12  also kill many types of viruses and fungi. However, alkyl monoalcohols  12  are not effective against all bacteria and virus. 
         [0012]    The term “alkyl monoalcohol,” as used herein, means alkyl monoalcohols  12  that include from 1 to 3 carbons and one hydroxyl group. As such, the term “alkyl monoalcohol,” as used herein, means one or more of methanol, ethanol, isopropanol, or n-propanol. Other alcohols may also be present in the hand sanitizer  10 , such as a butyl alcohol, 1,2 dipropanol, 1,3 dipropanol, etc., but the alkyl monoalcohol  12  is present at the concentration described above. The alkyl monoalcohols  12  are relatively volatile, and may evaporate after application to the hands or other surfaces that are in the open air. Alkyl monoalcohols  12  will remain in a solution when stored in a closed container, so refrigeration is generally not needed for the hand sanitizer  10 . Certain formulations of hand sanitizers  10  may limit or slow the evaporation of the alkyl monoalcohols  12  after being placed in an open area, such as on the hands. 
         [0013]    In some embodiments, a thickener  14  may be added to the hand sanitizer  10  at from about 0.01 to about 2 weight percent, or from about 0.01 to about 1 weight percent or from about 0.01 to about 0.5 weight percent in various embodiments. The thickener  14  may increase the viscosity of the hand sanitizer  10  to about 200 to about 300,000 centipoise in an exemplary embodiment, but the thickener  14  may increase the viscosity of the hand sanitizer  10  to about 500 to about 200,000 centipoise or about 1,000 to about 100,000 centipoise in alternate embodiments. The amount and type of thickener  14  can be adjusted for the desired viscosity. Thickeners  14  can produce a gel or a gel-type hand sanitizer  10 , and the thickener  14  can limit the evaporation rate of the alkyl monoalcohol  12  in some embodiments. 
         [0014]    Thickeners  14  that can be utilized are generally divided into organic and inorganic thickeners  14 . Organic thickeners  14  include: (1) cellulosic thickeners and their derivatives, including but not limited to carboxymethyl hydroxyethylcellulose, cellulose, hydroxybutyl methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropyl methyl cellulose, methylcellulose, microcrystalline cellulose, and sodium cellulose sulfate; (2) natural gums, including but not limited to the gums of acacia, calcium carrageenan, guar, gelatin, hydroxypropyl guar, karaya, kelp, locust bean, pectin, sodium carrageenan, tragacanth, and xanthan; (3) acrylates, including but not limited to polyacrylic acid copolymer, potassium aluminum polyacrylate, sodium acrylate/vinyl alcohol copolymer, and sodium polymethacrylate; (4) starches, including but not limited to oat flour, potato starch, wheat flour, and wheat starch; (5) stearates, including but not limited to methoxy polyethylene glycol (PEG)-22/dodecyl glycol copolymer, PEG-2M, and PEG-5M; and (6) fatty acid alcohols, including but not limited to caprylic alcohol, cetearyl alcohol, lauryl alcohol, stearyl alcohol, oleyl alcohol, cetyl alcohol, and palm kernel alcohol. Inorganic thickeners  14  include: (7) clays, including but not limited to bentonite, magnesium aluminum silicate, magnesium trisilicate, stearalkonium bentonite, and tromethamine magnesium aluminum silicate; and (8) salts, including but not limited to calcium chloride, sodium chloride, sodium sulfate, and ammonium chloride. Waxes and oils can also be used as thickeners  14  in some embodiments. Representative examples of waxes include, but are not limited to, candelilla wax, carnauba wax, and beeswax, and examples of oils include, but are not limited to, vegetable oils and animal oils. 
         [0015]    In some embodiment, the hand sanitizer  10  may be a foaming type of hand sanitizer  10 . The thickener  14  may or may not be present in foaming types of hand sanitizers  10 , and the viscosity of foaming type hand sanitizers  10  may be different than the viscosity of the gel type hand sanitizers  10 , as described below. The foaming hand sanitizer  10  may include a surfactant  16  that produces a foam with an alkyl monoalcohol  12 , such as many silicone polymer surfactants and/or fluorosurfactants. The gel-type hand sanitizers  10  may also include a surfactant  16 . In an exemplary embodiment, the surfactant  16  is present in the hand sanitizer  10  at from about 0.05 to about 8 weight percent, based on the total weight of the hand sanitizer  10 . In alternate embodiments, the surfactant  16  may be present in the hand sanitizer  10  from about 0.05 to about 5 weight percent, or from about 0.05 to about 2 weight percent. Examples of suitable surfactants  16  include, but are not limited to, one or more of dimethicone copolyols including but not limited to PEG 10 dimethicone and PEG-12 dimethicone, polysiloxane-polyether copolymers including but not limited to bis PEG polypropylene glycol (PPG) 20/20 dimethicone, dimethicones and dimethicone copolyols with polyethyleneoxide (PEO) and polypropylene oxide (PPO) side chains, polyoxyethylene ethers, polyoxyethylene esters, polyoxyethylene fatty acids, polyoxyethylene sulfated acids, sulfosuccinates, polysiloxane, sorbitan fatty acid esters, polyoxamers, linear PEG 8-PEG-12 dimethicones, dimethicone copolymers including but not limited to PEG/PPG 18/18, 17/18, 4112, 35/65, and combinations thereof. In some embodiments, the surfactant  16  is one or more of a fluorosurfactant and a silicone based surfactant, such as a silicone polymer surfactant. The foaming type of hand sanitizer  10  may have a viscosity of about 1 to about 1,000 centipoise in an exemplary embodiment, but in alternate embodiments the viscosity may be from about 3 to about 800 or from about 5 to about 500 centipoise. 
         [0016]    The hand sanitizer  10  may include antimicrobial agents in addition to the alkyl monoalcohol  12 , where the additional antimicrobial agents may impart an enhanced antimicrobial effect. The additional antimicrobial agents and other components described below may be present in foaming or gel type hand sanitizers  10 . In an exemplary embodiment, an “enhanced antimicrobial effect” means a bacterial kill rate for the hand sanitizer  10  that is greater than a bacterial kill rate for a test blank that consists of the alkyl monoalcohol  12  of the hand sanitizer in an aqueous solution, where the alkyl monoalcohol  12  is at the same concentration in the test blank and in the hand sanitizer  10  with the additional antimicrobial agents. An “enhanced antimicrobial effect” may also mean a more persistent antimicrobial effect, where the hand sanitizer  10  with the additional antimicrobial agents has an antimicrobial effect for a longer period of time than the test blank. Some or all of the additional antimicrobial agents may be less volatile than the alkyl monoalcohol  12  to provide a more persistent antimicrobial effect, and some or all of the additional antimicrobial agents may have a different type of antimicrobial activity that compliments the antimicrobial activity of the alkyl monoalcohol  12 . 
         [0017]    The hand sanitizer  10  may include one or more than one additional antimicrobial agents. One such antimicrobial agent is a glycerin alkyl ether  18 , which may be present in the hand sanitizer  10  at from about 0.1 to about 5 weight percent in an exemplary embodiment. In alternate embodiments, the glycerin alkyl ether  18  may be present at from about 0.1 to about 3 weight percent or from about 0.1 to about 1 weight percent, based on the total weight of the hand sanitizer  10 . The glycerin alkyl ether  18  may be a glycerin alkyl monoether in some embodiments, such that the glycerin alkyl ether  18  has the formula: (HO)—C—C(OH)—C—O—R, wherein R is an alkyl moiety. The alkyl moiety R may be a straight chain or branched in various embodiments. In an exemplary embodiment, the glycerin alkyl ether  18  is ethylhexylglycerin. 
         [0018]    Another antimicrobial agent that may be present in the hand sanitizer  10 , in addition to or in place of the glycerin alkyl ether  18  is a glycerin alkyl ester  20 . The glycerin alkyl ester  20  may be present at from about 0.1 to about 3 weight percent in an exemplary embodiment, based on the total weight of the hand sanitizer  10 . The glycerin alkyl ester  20  may be present at from about 0.1 to about 2 weight percent or from about 0.1 to about 1 weight percent in alternate embodiments. In some embodiments, the glycerin alkyl ester  20  is a glycerin alkyl monoester, such that the glycerin alkyl monoester has the formula (HO)—C—C(OH)—C—O—C(O)—R′, wherein R′ is an alkyl moiety. The alkyl moiety R′ may be a straight chain or a branched alkyl in various embodiments. In one embodiment, the glycerin alkyl ester  20  is glyceryl caprylate. 
         [0019]    Yet another antimicrobial agent that may be present in the hand sanitizer  10 , in addition to on in place of the glycerin alkyl ether  18  and/or the glycerin alkyl ester  20 , is an aromatic alcohol  22 . The aromatic alcohol  22  may be present in the hand sanitizer  10  at from about 0.1 to about 3 weight percent in some embodiments, based on the total weight of the hand sanitizer  10 , but the aromatic alcohol  22  may be present from about 0.1 to about 2 weight percent or from about 0.1 to about 1 weight percent in alternate embodiments. In an exemplary embodiment, the aromatic alcohol  22  is an aromatic alkyl monoalcohol, such that the aromatic alkyl monoalcohol has the formula C6H5-R″—(OH), wherein R″ is an alkyl moiety. The alkyl moiety R″ may be branched or straight in various embodiments. In an alternate embodiment, the aromatic alcohol  22  may be phenol. In one exemplary embodiment, the aromatic alcohol  22  is phenethyl alcohol. 
         [0020]    Additional antimicrobial agents may be used in some embodiments, and certain antimicrobial agents may not be present. In an exemplary embodiment, 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one are not present in the hand sanitizer  10 , such that 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one are present at from about 0 to about 0.0001 weight percent, based on the total weight of the hand sanitizer  10 . Other antimicrobial agents that may not be present include triclosan, povidone-iodine, and quaternary ammonium salts, each of which may not be present such that the concentration of triclosan, povidone-iodine, and/or quaternary ammonium salts is from about 0 to about 0.0001 weight percent, based on the total weight of the hand sanitizer  10 . However, in alternate embodiments, one or more of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, triclosan, povidone-iodine, and/or quaternary ammonium salts may be present, such as at from about 0.1 to about 5 weight percent, based on the total weight of the hand sanitizer  10 . 
         [0021]    The hand sanitizer  10  may optionally include several other components in various embodiments. For example, water  24  may be present at from about 5 to about 40 weight percent, based on the total weight of the hand sanitizer  10 . Water  24  may be present at from about 5 to about 30 weight percent or from about 10 to about 30 weight percent or from about 15 to about 30 weight percent in various embodiments, based on the total weight of the hand sanitizer  10 . Another optional ingredient includes one or more skin conditioners  26 , which may be present at from about 0.1 to about 5 weight percent in an exemplary embodiment. In alternate embodiments the skin conditioner  26  may be present at from about 0.1 to about 2 weight percent, or from about 0.5 to about 2 weight percent, based on the total weight of the hand sanitizer  10 . Several different compounds may serve as skin conditioners  26 , wherein the skin conditioner  26  is a moisturizer that helps to soften skin or to treat dry skin. A skin conditioner  26  increases the ability of the skin to hold water, and this provides the skin with a layer of oil to prevent water loss and to lubricate the skin. Exemplary embodiments of skin conditioners  26  include, but are not limited to: octyl isononanoate; cetyl myristate; glyceryl dioleate; methyl laurate; PPG-9 laurate; soy stearyl; octyl palmitate; PPG-5 lanoate; lanolin; propylene glycol; glycerine; fatty acids; natural oils such as almond, mineral, canola, sesame, avocado, balm mint, cod liver, soybean, wheat germ, corn, peanut, vegetable, and olive; isopropyl myristate; myristyl alcohol; aloe vera; hydrolyzed silk protein; vitamin E; stearyl alcohol; isopropyl palmitate; sorbitol; amino acid complexes; polyethylene glycol; agarose; arginine PCA; fructose; glucose; glutamic acid; honey; lactose; maltose; methicone; phenyl trimethicone; trimyristin; stearyl stearate; synthetic wax; cholesterol; cystine; keratin; lecithin; egg yolk; glycine; PPG-12; retinol; salicylic acid; orotic acid; vegetable oil; and others. 
         [0022]    The hand sanitizer  10  may also include fragrance  28  in some embodiments. As used herein, “fragrance” is a chemical compound that humans can detect by smell, where the fragrance is added to the hand sanitizer  10  for the purpose of its smell. The fragrance  28  may be present in the hand sanitizer  10  at from about 0 to about 5 weight percent, but the fragrance  28  may be present in the hand sanitizer  10  at from about 0.01 to about 5 weight percent, or from about 0.01 to about 3 weight percent, or from about 0.01 to about 0.5 weight percent in various embodiments, based on the total weight of the hand sanitizer  10 . Many compounds may be added as a fragrance  28 , including but not limited to: natural extracts, oils, resinoids, resins, and/or essences which may include one or more of many different constituents, such as orange, lemon, rose, nutmeg, lavender, musk, patchouli, balsam, sandalwood, pine, cedar, and  cassia;  7-acetyl-1, 2, 3, 4, 5, 6, 7, 8-octahydro-1, 1, 6, 7-tetramethylnaphthalene, -ionone, β-ionone, γ-ionone, a-isomethylionone; methyl cedryl ketone; methyl dihydrojasmonate; methyl 1, 6, 10-trimethyl-2, 5, 9-cyclododecatrien-1-yl ketone; 4-acetyl-6-tert-butyl-1, 1-dimethylindane; hydroxyphenylbutanone; benzophenone; methyl β-naphthyl ketone; 6-acetyl-1, 1, 2, 3, 3, 5-hexamethylindane; 5-acetyl-3-isopropyl-1, 1, 2, 6-tetramethylindane; 1-dodecanal; 4-(4-hydroxy-4-methylpentyl)-3-cyclohexene-1-carboxaldehyde; 7-dimethyloctanal; 10-undecen-1-al; isohexenylcyclohexylcarboxaldehyde; formyl tricyclodecane; condensation products of hydroxycitronellal and methyl anthranilate; condensation products of hydroxycitronellal and indole; condensation products of phenylacetaldehyde and indole; 2-methyl-3-(para-tert-butylphenyl) propionaldehyde; ethylvanillin; heliotropin; hexylcinnamaldehyde; amylcinnamaldehyde; 2-methyl-2-(isopropylphenyl) propionaldehyde; coumarin; decalactone-γ; cyclopentadecanolide; 16-hydroxy-9-hexadecenolactone; 1, 3, 4, 6, 7, 8-hexahydro-4, 6, 6, 7, 8, 8-hexamethylcyclopenta-Y-2-benzopyran; β-naphthol methyl ether; ambroxan; 5-(2,2,3-trimethylcyclopent-3-enyl)-3-methylpentan-2-ol; 2-ethyl-4-(2, 2, 3-trimethyl-3-cyclopenten-1-yl)-2-buten-1-ol; caryophyllene alcohol; tricyclodecenyl propionate; tricyclodecenyl acetate; benzyl salicylate; cedryl acetate; tert-butyleyelohexyl acetate; and many other compounds. 
         [0023]    The hand sanitizer  10  may be produced by combining the components described above. In an exemplary embodiment, the components described above are combined at the concentrations described above in a vessel  30  and mixed, such as with an agitator  32 , but in-line mixers or other methods of mixing may also be used. In alternate embodiments, some of the components described above may be mixed together, and other components may be added and blended until the desired hand sanitizer  10  is produced. The hand sanitizer  10  may then be packaged in a container  34 , and a pump  36  may be affixed to the container  34 . The pump  36  may be a hand pump in some embodiments, but the pump  36  may also be electrically activated or otherwise activated to dispense the hand sanitizer  10  in alternate embodiments. In yet other embodiments, the container  34  includes a lid (not illustrated), where the lid may not include a pump  36  such that the hand sanitizer  10  is dispensed by pouring or squeezing the hand sanitizer  10  out of the container  34 . In some embodiments, the pump  36  may combine air with the hand sanitizer  10  prior to the hand sanitizer  10  exiting the pump  36 , such that the hand sanitizer  10  foams when dispensed. 
         [0024]    The hand sanitizer  10  may be used by applying an effective amount of hand sanitizer  10  to the hands of a person, and spreading the hand sanitizer  10  over the surface of the skin. An effective amount is the amount of hand sanitizer  10  that kills at least about 90 percent of the bacteria on the surface where the hand sanitizer  10  is applied. In an exemplary embodiment, an effective amount of hand sanitizer  10  is about 0.005 grams per square centimeter of skin or other surface that the hand sanitizer  10  is spread over. 
         [0025]    Table 1 below shows test data that illustrates the improved efficacy of hand sanitizers with antimicrobials (labelled “additive”) other than ethanol. The test results in the Table 1 are based on a 2.0 milliliter (ml) dose of a test hand sanitizer, and all results are based on reducing the bacteria  Serratia Marcescens  ATCC 14756 after 1 treatment. Bacterial counts were converted into Log 10  reduction values, where higher values indicate higher antibacterial efficacy. 
         [0000]    
       
         
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Sample 
                 % ethanol 
                 Additive 
                 Percent additive 
                 Log 10  reduction 
               
               
                   
               
             
             
               
                 1 
                 62 
                 None 
                 N/A 
                 1.73 
               
               
                 2 
                 70 
                 ethylhexylglycerin 
                 1.0 
                 2.46 
               
               
                 3 
                 70 
                 glyceryl caprylate 
                 1.0 
                 2.17 
               
               
                   
               
             
          
         
       
     
         [0026]    While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the application in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing one or more embodiments, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope, as set forth in the appended claims.