You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND 
       [0001]    Diseases and infections can be transmitted by indirect contact. Any contact surface, which is touched by more than one person, can be a transfer point for harmful germs spreading diseases and infections through a population. An example is the common cold. A person, who has a cold, can leave cold virus behind on a door handle he or she touches. A non-infected person, who later touches the door handle, can pick up the cold virus from the door handle and catch the same cold. 
         [0002]    For certain high risk environments (e.g., restrooms, food service and health care facilities), public health programs recommend hand washing or hand rubbing routines for maintaining good hand hygiene to prevent or reduce propagation of communicable diseases and infections. However, time and facilities constraints present are major obstacles to maintaining good hand hygiene. Many studies of nosocomial infections show that hand washing protocols are not properly followed even by health care providers. General compliance rates of health care providers with hospital-recommended hand washing or hand rubbing protocols are low. The poor compliance rates have been attributed in part to a lack of knowledge of when and how to clean or disinfect hands, and in part to time constraints and poor access to hand washing facilities or hand rubbing products. (See e.g., Albert R. K., Condie F., NEJM 1981;304(24):1465-6). 
         [0003]    The time and facilities constraints that impede good hand hygiene in hospital environments are even more severe obstacles for achieving good hand hygiene in other public environments. For example, it is not practical to provide hand washing facilities at every door knob or entrance in a working office building, or at every turnstile or contact surface in a bus or train terminal. Further, even where hand washing facilities are provided (e.g., in restrooms), hand washing can be counterproductive. A person, after washing hands, could pick up germs by turning a water faucet handle off, or touching a restroom exit door handle. 
         [0004]    Consideration is now being given to other solutions for limiting the undesirable spread of pathogens by indirect contact. Some such solutions may avoid, for example, the time and facilities constraints that hinder solutions that rely on voluntary hand washing by individuals. 
       SUMMARY 
       [0005]    Approaches to limiting the spread of pathogens, for example, by indirect contact are provided. One approach utilizes self-sterilizing contact surface structures. A self-sterilizing contact surface structure may be disposed on any article, fixture or substrate in any environment, which can be touched by a person. 
         [0006]    In one approach, the self-sterilizing contact surface structure includes an exterior contact surface, which can be touched, and an interior chemical flow-conductive region which is contiguous to the exterior contact surface. The self-sterilizing contact surface structure is configured so that a sterilizing chemical agent can be controllably transconducted across the interior chemical flow-conductive region on to at least a portion of the exterior contact surface. The self-sterilizing contact surface structure includes egress ports or openings through which transconducted sterilizing chemical agent can exude on to the exterior contact surface. The flow of the sterilizing chemical agent to the exterior contact surface can be triggered by specific events (e.g., contact, imminent contact, or lapse of time). 
         [0007]    The self-sterilizing contact surface structure may include one or more sensors (e.g., contact sensor, a proximity sensor, or a chemical sensor) which are configured to detect if a contact has occurred or is likely, or if biomaterials are present on the exterior contact surface. Further, the structure may include, or be coupled to, control elements that control, time or regulate the flow of the sterilizing chemical agent on to the contact surface in response to events. The control elements may act in response to, for example, sensor information, contact surface activity, and/or other control signals. Additionally, the structure may include, or be coupled to, a power source/receiver, which provides energy for the controlled flow of the sterilizing chemical agent. Like the control elements, the power source/receiver may be responsive to sensor information, contact surface activity, and/or control signals. A contact surface status indicator coupled to the structure may display a sterilization condition or state of the contact surface to users. Similarly, a refill indicator coupled to the structure may display a refill state of the sterilizing chemical supply. 
         [0008]    The foregoing summary is illustrative only and is not intended to be limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the solutions will become apparent by reference to the drawings and the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES  
         [0009]    In the accompanying drawings: 
           [0010]      FIG. 1  is a schematic illustration of exemplary self-sterilizing articles or fixtures, which have contact surfaces that are self-sterilized to prevent or reduce the spread of communicable diseases and infections by indirect contact, in accordance with the principles of the solutions described herein; 
           [0011]      FIG. 2  is a block diagram illustrating an exemplary system for dispensing sterilizing agent in an article or fixture having a self-sterilizing contact surface, in accordance with the principles of the solutions described herein; 
           [0012]      FIG. 3  is a schematic illustration of the self-sterilizing contact surface of  FIG. 1 , in accordance with the principles of the solutions described herein; 
           [0013]      FIG. 4  is a block diagram illustrating an arrangement of exemplary control elements that control or regulate flow of a sterilizing chemical to the self-sterilizing contact surface of  FIGS. 1-3 , in accordance with the principles of the solutions described herein; and 
           [0014]      FIGS. 5 and 6  are flow diagrams illustrating exemplary methods for inhibiting the spread of germs by indirect contact, in accordance with the principles of the solutions described herein. 
       
    
    
       [0015]    Throughout the figures, unless otherwise stated, the same reference numerals and characters are used to denote like features, elements, components, or portions of the illustrated embodiments. 
       DESCRIPTION 
       [0016]    In the following description of exemplary embodiments, reference is made to the accompanying drawings, which form a part hereof. It will be understood that embodiments described herein are exemplary, but are not meant to be limiting. Further, it will be appreciated that the solutions described herein can be practiced or implemented by other than the described embodiments. Modified embodiments or alternate embodiments may be utilized, in the sprit and scope of the solutions described herein. 
         [0017]      FIGS. 1-4  show exemplary self-sterilizing articles  100 , each having an article body  120  with a contact surface  101  disposed thereon. Exemplary articles  100 , as shown for purposes of illustration in  FIG. 1 , are door handles having particular shapes. Article  100  may, however, be any device or fixture of any shape having one or more surfaces that can be touched or contacted in use. Article  100  may, for example, be a handle, a hand rail, a seat, a key board, a switch, a button, a knob, a computer mouse or control device, a desktop, a bathroom or kitchen or other working surface, a bus seat, a gymnasium apparatus or fixture, a restaurant booth or seat, a toy, a headphone, a telephone, an automatic teller machine, a vending machine, a shopping cart, a household device or fixture, a building device or fixture, an industrial device or fixture, a transport vehicle device or fixture, a medical device or fixture, or any other device or fixture whose contact surfaces are sites for potential transfer of undesirable pathogens amongst users. 
         [0018]    With reference to  FIG. 2 , self-sterilizing article  100  is coupled to a chemical dispenser system  103 , which is arranged to controllably dispense or deliver a chemical  104  on to contact surface  101  from within body  120 . Chemical  104  may, for example, be a sterilizing chemical, which reduces or kills pathogens (e.g., bacteria, viruses, or germs), which may be present on contact surface  101 . Suitable sterilizing chemicals  104  may, for example, include one or more of inorganic or organic compounds, oxidizers, halogens, alcohols, amine- or hypochlorite-based chemicals, or any other germicidal chemicals or compounds. Chemical  104  may be dispensed in any suitable physical state (e.g., solid, gas, liquid or gel). Preferably, sterilizing chemical  104  is such that it vaporizes or sublimes from contact surface  101  after delivery without leaving behind any substantial residues. 
         [0019]    Pre-prepared chemical  104 , which is ready for dispensing, may be obtained from a chemical reservoir  105 . Alternatively, chemical  104  may be prepared in situ, for example, in a chemical generator  106 . For example, chemical  104  may be chlorine gas, or liquid bleach prepared by self-liquefaction of a mixture of calcium hypochlorite (Ca(OCl) 2 ) laced with calcium chloride (CaCl 2 ) in chemical generator  106  (e.g., under contact-induced pressure). 
         [0020]    In operation, controlled amounts of chemical  104  are dispensed or delivered by chemical dispenser system  103  onto contact surface  101  from within article  100 . For this purpose, chemical dispenser system  103  may include, or be linked to a source of chemical  104  (e.g., reservoir  105 /generator  106 ). The chemical source may be internal to article  100 /body  120 , as shown, for example, in  FIG. 2 . Alternatively, the chemical source of chemical  104  may be external to article  100 /body  120 , as shown for example, in  FIG. 4 . Thus, in the example of a building door handle article, the chemical source may be placed in the door handle itself, the door, or any other part of the building structure. 
         [0021]    In any case, suitable conductive passageways or channels  115  that cross interface region  102  guide a flow of chemical  104  obtained from the chemical source onto contact surface  101 , which has suitable surface ports or openings  115 ′ for egress of chemical  104 . Surface ports or openings  115 ′ may be distributed over the entire area of contact surface  101 . Alternatively, contact surface  101  may be patterned so that surface ports or openings  115 ′ are present only in select regions (e.g., regions  116 A-C) while other regions (e.g., region  117 ) are free of such ports or openings (see  FIG. 3 ). 
         [0022]    Embodiments of chemical dispenser system  103  may include, or operationally interface with, one or more other electrical and/or mechanical components configured to recognize and respond to events, and control the flow of chemical  104 . For example, chemical dispenser system  103  may optionally include a controller  107 , a pumping mechanism  108 , a sensor  109 , a status/refill indicator  110 , a timer  111 , a counter  112 , a power source/receiver  113 , and/or a programmable interface  114 . Like chemical reservoir  105  described above, each of these optional components may be disposed either inside or outside article  100  (see  FIG. 4 ). 
         [0023]    With reference to  FIGS. 2 and 4 , the flow of chemical  104  across the interface  102  onto contact surface  101  is driven by pumping or regulating mechanism  108 . Pumping mechanism  108  may, for example, be an electromechanical pump. Alternative versions of pumping mechanism  108  may, for example, include elasticity- or strain-, mechanical-, pressure-, temperature-, surface tension-, osmotic pressure-, and/or gravity-actuated prime movers. 
         [0024]    Suitable energy or power for operating pumping mechanism  108  may be obtained from an internal or external power source/receiver  113  (e.g., a dry cell or a wound spring or resonant inductive power reception circuitry). Further, operation or movement of article  100  itself may be utilized to generate energy or power for driving pumping mechanism  108  or other components of chemical dispenser system  103 . For example, contact-induced pressure and/or contact-induced temperature may be utilized to drive or regulate the flow of chemical  104  (e.g., using a pressure- or temperature-activated flow switch). 
         [0025]    Additionally or alternatively, article  100  may be coupled to an energy- or power-generating mechanism (e.g., generator  116 ). Generator  116  may, for example, couple mechanical movement of article  100  (e.g., turning of a door handle, or opening of a door) to drive pumping mechanism  108  directly. For this purpose, generator  116  may include any suitable mechanical coupling arrangement (e.g., levers and springs). Alternatively, generator  116  may be configured to convert mechanical movement of article  100  into storable elastic, electrical or other energy. Generator  116  may include any suitable mechanical and/or electromechanical converter arrangements (e.g., springs, coils, inductors, and magnets) for this purpose. The energy generated in this manner by generator  116  may be used either directly to drive pumping mechanism  108 , or stored for later use (e.g., in power source/receiver  113 ). 
         [0026]    Chemical dispensing system  103  including pumping mechanism  108  may include flow-regulating features (e.g., pressure-activated flow switches, and orifices and channels having predetermined flow-impedance) to control timing and delivery amounts of chemical  104  to contact surface  101 . More generally, the operation of chemical dispensing system  103  may be supervised by a control device or system. 
         [0027]    Chemical dispensing system  103  also may include, or be coupled to, a used chemical recovery or disposal system that is arranged to collect residual chemicals from contact surface  101 . An exemplary used chemical recovery/disposal system may include a used-chemical reservoir  118 , which is gravity-fed. Another exemplary used chemical recovery/disposal system may include a heater arrangement (not shown) to vaporize residual chemicals from contact surface  101 . 
         [0028]      FIG. 4  shows an exemplary controller  107  configured to supervise operation of chemical dispensing system  103 . Controller  107  may have any suitable mechanical or electromechanical structure, and include an optional programmable interface  114 . In operation, controller  107  may control timing and amounts of chemical  104  delivered to contact surface  101  in response to one or more event-triggered control signals. The event-triggered control signals may be generated by one or more control elements. The control elements may, for example, include one or more of sensor  109 , timer  111 , counter  112 , or a user-activated switch (not shown). As noted previously, each of these control elements may be disposed either inside or outside article  100 . 
         [0029]    Sensor  109  may be a contact sensor which is configured to determine if a contact has been made to contact surface  101  and to accordingly generate a control signal to activate chemical dispenser system  103  directly, or via controller  107 , to provide chemical  104  across interface region  102 . The contact sensor may, for example, be any of a capacitive, a resistive, a thermal, a mechanical, a piezoelectric, an ultrasonic, an electromagnetic, or an optical sensor. 
         [0030]    Additionally or alternatively, sensor  109  may be a proximity sensor arranged to determine if a contact to contact surface  101  is likely, and to accordingly generate a control signal to activate chemical dispenser system  103  directly, or via controller  107 , to provide chemical  104  across interface region  102 . Like the contact sensor, the proximity sensor may, for example, be any of a capacitive, a resistive, a thermal, a mechanical, a piezoelectric, an ultrasonic, an electromagnetic, or an optical sensor. 
         [0031]    Further, sensor  109  may be a bio- or chemical sensor arranged to determine a presence of biological materials (e.g., sweat, lipids, etc.) on contact surface  101 , and to accordingly generate a control signal to activate chemical dispenser system  103  directly, or via controller  107 , to provide chemical  104  across interface region  102 . 
         [0032]      FIGS. 2 and 4 , for visual clarity, show a solitary sensor  109 . However, it will be understood that any suitable numbers of sensors of various types may be deployed. Further, the sensor(s) may be configured to identify particular portions or sub regions of contact surface  101  of interest, and to accordingly activate dispenser system  103  directly, or via controller  107 , to provide chemical  104  across interface region  102  only to those particular portions or subregions if so desired. For example, sensor  109 , in addition to determining if a contact is made, may be further configured to determine a location of contact. With reference to  FIG. 3 , such a sensor  109  may, for example, determine that only subregion  116 B of contact surface  101  has been contacted or touched. Accordingly, chemical dispenser system  103  may be activated to provide chemical  104  only to subregion  116 B, if so desired. Alternatively, chemical dispenser system  103  may be activated to provide chemical  104  to all subregions  116 A-C of contact surface  101  even though only subregion  116 B has been contacted or touched. 
         [0033]    Control elements such as timer  111  or counter  112  also may generate alternate or additional event-triggered control signals to activate chemical dispenser system  103  only at certain times and/or only for particular durations. For example, counter  112 , which may be an indexed or resettable counter, may count a number of contacts made, and activate chemical dispenser system  103  to provide chemical  104  each time the counted number equals or exceeds a predetermined number. Similarly, controller  107  may be coupled to timer  111 , which clocks or times the provision of chemical  104  across interface  102 . Controller  107  may be further configured to respond to various sensor signals so that provision of chemical  104  across interface  102  begins a predetermined time interval after a contact is made, before a contact is made, or during a contact. In any case, the provision of chemical  104  may be continuous for a predetermined time interval after a triggering event. 
         [0034]    Alternatively or additionally, controller  107  may be further configured to control provision of chemical  104  across interface  102  according to predetermined schedules. A predetermined schedule may be independent of the state or condition of contact surface  101 . For example, a predetermined schedule may ask for chemical  104  to be released every ten minutes, independent of the number of contacts made in the interim. Alternative predetermined schedules may be flexible or adjustable to take into consideration events, including without limitation, events potentially affecting contact surface  101 . For example, chemical  104  may be scheduled to be routinely released every ten minutes, but the schedule may be advanced or supplemented if a number of contacts made in the interim exceeds three. Similarly, timing or amount of release of chemical  104  may be responsive to a number of persons in a region proximate the contact surface  101  or to other environmental events (e.g. changes in heating, ventilation, and air conditioning (HVAC) operation in the area or building). Moreover, the schedule, amount, or other aspects of release of chemical  104  may be controlled by controller  107  or other controller systems that may be located nearby or distant from contact surface  101 . In one approach, for example, the schedule, amount, or other aspects of release of the sterilizing chemical  104  may be controlled through a remote control system in a different building or facility, for example, through wireless, wired, IP protocol or other approaches. 
         [0035]    The predetermined schedules and the responses of chemical dispensing system  103 /controller  107  to various control signals may be set up or programmed by a user, for example, through programmable interface  114 . 
         [0036]    Article  100  also may include an optional status indicator  110 , which is configured to indicate a state of the contact surface and/or chemical dispensing system  103 . Status indicator  110  may, for example, include a set of red, yellow and green color light emitting diodes corresponding to various sterilization states of contact surface as determined by one or more sensors or control elements. Other versions of status indicator  110  may include other visual, audio, RF or electromagnetic and/or tactile displays of the contact surface state. Similarly, the same or another status/refill indicator  110  may display a state of chemical dispensing system  103  (e.g., refill state of a chemical reservoir). 
         [0037]      FIGS. 5 and 6  show exemplary features of methods for inhibiting germ transmission from contact surfaces. The methods involve self-sterilization of the contact surfaces. 
         [0038]      FIG. 5  shows a method  500  for sterilizing an exterior contact surface disposed on an article, which includes a subsurface or interior region adjacent or contiguous to the exterior contact surface. Method  500  includes: in response to an event, controllably transconducting a sterilizing chemical agent from within the article to a portion of the exterior contact surface through an interior region contiguous to the exterior contact surface ( 520 ). The controllable flow is initiated, sustained or terminated, in response to receiving at least one of a contact sensor, a proximity sensor, or a timing sensor signal ( 510 ). Method  500  also optionally includes displaying or indicating a status of the contact surface ( 530 ). 
         [0039]      FIG. 6  shows another method  600  for sterilizing an exterior contact surface disposed on an article body. Method  600  includes determining a state of the contact surface ( 610 ), and in response, controllably providing a sterilizing chemical agent from within the article body across an interface between the article body and the contact surface ( 620 ). At least a portion of the contact surface is sterilized by action of the sterilizing chemical agent provided from within the article body. 
         [0040]    In method  600 , determining a state of the contact surface ( 610 ) many include determining if a contact has been made to the contact surface, or is likely to be made. Any suitable contact or proximity sensor may be used for this purpose. Additionally or alternatively, determining a state of the contact surface ( 610 ) may involve determining if biological materials are present on the contact surface by deploying a bio- or chemical sensor. 
         [0041]    Further, in method  600 , controllably providing a sterilizing chemical agent from within the article body across an interface between the article body and the contact surface ( 620 ) may include flowing the sterilizing chemical agent across the interface through pores or channels in the interface and out through ports or openings in the contact surface. The provision of the sterilizing chemical agent may occur according to a programmed routine or a predetermined schedule Controllably providing a sterilizing chemical agent from within the article body across the interface may include timing of the provision of the sterilizing chemical across the interface, providing the sterilizing chemical agent a predetermined time interval before, during or after a contact is made, providing the sterilizing chemical agent after a predetermined number of contacts, and/or providing the sterilizing chemical agent continuously for a predetermined time interval. 
         [0042]    The flow of the sterilizing chemical agent across the interface, in method  600 , may be driven by pressure, temperature, surface tension, gravity, a contact-induced pressure or temperature, and/or a pumping device. Contact-actuated power may be utilized to controllably move the sterilizing chemical across the interface. The contact-actuated power may be generated by a movable mechanism, for example, a pressure-activated mechanism. Method  600  may further include storing contact-actuated power to controllably move the sterilizing chemical across the interface at a later time. 
         [0043]    Further, method  600  may include supplying the sterilizing chemical agent from an internal chemical supply reservoir, generating the sterilizing chemical agent internally in the article, recovering residual chemicals from the contact surface, and/or storing recovered residual chemicals in a used-chemical reservoir. The controllably provided sterilizing chemical agent may be a chemical which vaporizes at the contact surface, an amine- or hypochlorite-based chemical, an oxidizer, and/or an alcohol. 
         [0044]    Like method  500 , method  600  also optionally includes displaying or indicating a status of the contact surface. The display may be audio, visual, tactile or any combination thereof. 
         [0045]    While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. For example, controlled amounts of sterilizing chemical  104  may be dispensed onto contact surface  101  from within article  100 , not merely in response to a sterilization state or condition of the contact surface, but additionally or alternatively in response to movement or orientation of article  100  or portions thereof. Thus, a door knob may be self-sterilized in response to a door closing motion. similarly, a tooth brush may be self-sterilized after it is picked up. A key may be self-sterilized after it is held in horizontal orientation as in a lock keyhole. Similarly, the tooth brush may be self-sterilized after it is placed vertically in a tooth-brush stand. 
         [0046]    It will be understood that the various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Summary:
Solutions for limiting the undesirable spread of pathogens by indirect contact are provided. The solutions involve event-controlled self-sterilization of contact surfaces on articles or fixtures. A self-sterilizing contact surface structure allows chemical sterilizing agents to controllably flow in response to a contact event, from within the article to exude upon a portion of the contact surface.