Abstract:
A particle classifying apparatus is described, a representative one of which includes: a light source for irradiating light to a sample containing urine; a light-receiving device for receiving light from the sample irradiated with light; and means for classifying a first cast appearing in urine in the case of a disease from the other particles contained in the sample based upon an output from the light-receiving device.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a particle classifying apparatus and a method for such an apparatus, and more particularly, concerns an apparatus used for classifying particle components in urine.  
       BACKGROUND  
       [0002]     Conventionally, particle components contained in urine have been analyzed so as to detect a disease in the kidney and the bladder. In the urine, cast, mucous cells, epithelial cells, white blood cell or the like are contained as particle components. The cast, which form one of the particle components, tend to appear not only in the case of a disease but also in a normal state, and the cast (cast appearing in the case of a disease) that appear in urine in the case of a disease contain more white blood cell and other cell components in comparison with cast (cast appearing in a normal state) that appear in a normal state.  
         [0003]     With respect to the apparatus for analyzing the particle components in urine, for example, a particle analyzer disclosed in U.S. Pat. No. 5,719,666 has been known. The analyzer, disclosed in the above-mentioned patent gazette, can classify components, such as cast, mucous cells, epithelial cells and white blood cell. However, the above mentioned analyzer cannot finely classify the cast into the cast appearing in the case of a disease and the cast appearing in a normal state.  
       SUMMARY  
       [0004]     The present invention has been devised to solve the above-mentioned problems, and its objective is to provide a particle classifying apparatus capable of finely classifying cast and a method for such an apparatus.  
         [0005]     In accordance with a first aspect of the present invention, the particle classifying apparatus is constituted by a light source for irradiating light to a sample containing urine; a light-receiving device for reciving light from the sample irradiated with the light; and a means that classifies a first cast appearing in urine in the case of a disease from the other particles contained in the sample based upon an output from the light-receiving device.  
         [0006]     In accordance with a second aspect of the present invention, the particle classifying apparatus is constituted by a light source for irradiating light to a sample containing urine; a light-receiving device for reciving light from particles in the sample irradiated with light, and outputs a particle signal corresponding to the particles; and a means that classifies a first cast appearing in the urine in the case of a disease from the other particles contained in the sample based upon a first pulse width that indicates a period of time during which the particle signal exceeds a first threshold value and a second pulse width that indicates a period of time during which the particle signal exceeds a second threshold value that is greater than the first threshold value.  
         [0007]     In accordance with a third aspect of the present invention, the particle classifying method is constituted by the following steps: a step of applying light to a sample containing urine; a step of receiving light from the sample irradiated with the light by using a light-receiving device; and a step of classifying a cast appearing in urine in the case of a disease from the other particles contained in the sample based upon an output from the light-receiving device. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a perspective view that shows an entire external structure of an analyzer for particle components in urine in accordance with one embodiment of the present invention.  
         [0009]      FIG. 2  is a block diagram that shows an essential portion of the analyzer shown in  FIG. 1 .  
         [0010]      FIG. 3  is a system diagram that shows a fluid system of the analyzer shown in  FIG. 1 .  
         [0011]      FIG. 4  is a perspective view that shows a detection unit of the analyzer shown in  FIG. 1 .  
         [0012]      FIG. 5  is a block diagram that shows a pulse width calculation unit of the analyzer shown in  FIG. 1 .  
         [0013]      FIG. 6  is a waveform drawing of electric signals of the analyzer shown in  FIG. 1 .  
         [0014]      FIG. 7  is an explanatory drawing that indicates a cast and the contents thereof.  
         [0015]      FIG. 8  is an example of a dispersion drawing that is formed by the analyzer shown in  FIG. 1 .  
         [0016]      FIG. 9  is an example of a dispersion drawing that is formed by the analyzer shown in  FIG. 1 .  
         [0017]      FIG. 10  is a block diagram that shows a hardware structure of a control unit shown in  FIG. 2 .  
         [0018]      FIG. 11  is a flow chart that explains a classifying flow of particle components in urine relating to processes in the control unit shown in  FIG. 10 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]     The preferred embodiments of the present invention will be explained below with reference to the drawings. In the following embodiments, for example, an analyzer for particle components in urine will be explained as the particle classifying apparatus in accordance with the present invention.  
         [0020]      FIG. 1  is a perspective view that shows an entire external structure of an analyzer for particle components in urine in accordance with one embodiment of the present invention.  FIG. 2  is a block diagram that explains an essential portion of the analyzer for particle components in urine in accordance with the embodiment shown in  FIG. 1 .  FIG. 3  is a system diagram that explains a fluid system of the analyzer for particle components in urine in accordance with the embodiment shown in  FIG. 1 .  FIG. 4  is a perspective view that explains a structure of a detection unit of the analyzer for particle components in urine in accordance with the embodiment shown in  FIG. 1 .  FIG. 5  is a block diagram that explains a structure of a pulse width calculation unit to be used in the analyzer for particle components in urine in accordance with the embodiment shown in  FIG. 1 .  FIG. 10  is a block diagram that shows a hardware structure of a control unit  69  shown in  FIG. 2 .  
         [0000]     Structure of Analyzer for Particle Components in Urine  
         [0021]     Referring to FIGS.  1  to  5  and  FIG. 10 , the following description will explain a structure of an analyzer for particle components in urine in accordance with one embodiment of the present invention.  
         [0022]     As shown in  FIG. 1 , an analyzer for particle components in urine in accordance with the present embodiment, which is provided with an apparatus main body  100 , a table  101  and a power source  102  that includes a power supply and an air pressure supply, has functions for classifying particle components in a urine sample in a specimen container  13  into red blood cell, white blood cell, epithelial cells, cast and bacteria. Moreover, a display operation unit  67  made of a liquid crystal screen is placed on the upper portion of the front face of the apparatus main body  100 . Various pieces of information, such as the results of classification of a urine sample and various setting values, are displayed on the display operation unit  67 . The display operation unit  67  also functions as a touch panel, and also serves as an operation unit for operating the apparatus. More specifically, various settings relating to measurements of the urine sample and operation keys used for selecting various functions are displayed on the liquid crystal screen of the display operation unit  67  so that the user is allowed to carry out operations, such as various settings and selections of various functions, by touching the operation keys on the liquid crystal screen. A suction pipette  11  used for sucking urine from the specimen container  13  is placed in the center of the front face of the apparatus main body  100 . Moreover, a start switch  12  is placed on the right side in the center of the front face of the apparatus.  
         [0023]     Referring to FIGS.  2  to  4  and  FIG. 10 , the following description will further describe the analyzer for particle components in urine in detail.  
         [0024]     As shown in  FIG. 2 , the analyzer for particle components in urine is provided with an analyzing unit  35 . The analyzing unit  35  is provided with a control unit  69  and a pulse width calculation unit  62 . The control unit  69  is provided with a particle classifying unit  64  including a dispersion drawing forming unit  65 , and a data storage unit  63 . The control unit  69 , which receives outputs from the operation unit  61  and the start switch  12 , controls a fluid-system driving unit  66  and a detection unit  68 . Moreover, the pulse width calculation unit  62 , which receives an output from the detection unit  68 , calculates the pulse width. The control unit  69  stores the data of the calculated pulse width in the data storage unit  63 , and the particle classifying unit  64  forms a dispersion drawing in the dispersion drawing forming unit  65  based upon the pulse width data so that particle components in urine are classified. The control unit  69  is constituted by microcomputers including a CPU, ROM, RAM or the like. The data storage unit  63  is constituted by a memory such as a RAM.  
         [0025]     Referring to  FIG. 10 , the structure of the control unit  69  is further explained. The control unit  69  is provided with a CPU  80   a , a ROM  80   b , a RAM  80   c , an input/output (I/O) interface  80   d  and an image-output interface  80   e . The ROM  80   b  stores an operating system, a control program used for controlling operations of the apparatus, data required for running the control program, an application program used for classifying particle components in urine, which will be described later, and data required for executing the application program. The CPU  80   a  is capable of loading the control program or the application program into the RAM  80   c  so as to be run , or directly runs the program through the ROM  80   b . Thus, the resulting data after the processes by the CPU  80   a  are transmitted to the respective units of the apparatus through the input/output interface  20   d , and data required for the processes of the CPU  80   a  are received from the respective units of the apparatus through the input/output interface  20   d . By running the control program, the CPU  80   a  can control the fluid-system driving unit  66  of the analyzer for particle components in urine, which will be described later. Moreover, by executing the application program, the CPU  80   a  forms a two-dimensional dispersion drawing, which will be described later, so that the particle components in urine are classified, and allows the display operation unit  67  to display the results.  
         [0026]     The analyzer for particle components in urine is also provided with a fluid system as shown in  FIG. 3 . This fluid system is constituted by a sheath flow cell  23  containing a cell  1  and a nozzle  6 , a fixed-amount syringe  44  that is connected to the nozzle  6 , a motor  44   a  that drives the piston  44   b  of the fixed-amount syringe  44 , a reaction chamber  48  that is connected to the nozzle  6  through an electromagnetic valve  46 , a sheath liquid chamber  42  that is connected to the cell  1  through an electromagnetic valve  50  and is also connected to the fixed-amount syringe  44  through an electromagnetic valve  41 , a pressure device  43  that applies a positive pressure to the sheath liquid chamber  42 , a suction device  49  that is connected to the nozzle  6  through an electromagnetic valve  47 , a waste chamber  45  that is connected to the cell  1 , and an electromagnetic valve  57  that is used for discharging the waste from the waste chamber  45 . Here, the motor  44   a , the electromagnetic valves  41 ,  46  and  47 , the pressure device  43  and the suction device  49  constitute the fluid-system driving unit  66  shown in  FIG. 2 .  
         [0027]     More specifically, the detection unit  68  shown in  FIG. 2  has a structure shown in  FIG. 4 . In other words, the detection unit  68  is provided with a laser diode  21  and a collimate lens  22  used for illuminating an orifice section of the sheath flow cell  23 , a condenser lens  27 , a dichroic mirror  28  and a photomultiplier tube (hereinafter, referred to as photomultiplier)  36  that are used for detecting side scattered light from particles and a filter  29 , a pin-hole plate  30  and a photomultiplier  31  that are used for detecting side fluorescent light from the particles. Moreover, amplifiers  33  or  34 , which respectively amplify signals respectively outputted from the photomultipliers  36  and  31 , and input the resulting signals to the selection unit  79  ( FIG. 5 ), are also installed.  
         [0028]     More specifically, the pulse width calculation unit  62  shown in  FIG. 2  has a structure shown in  FIG. 5 . In other words, the pulse width calculation unit  62  is provided with a selection unit  79  that selects either of two output signals (output signals from the amplifiers  33  and  34 ) from the detection unit  68  ( FIG. 4 ), and outputs the resulting signal, a digital filter  71  that filters the output of the selection unit  79 , first and second threshold-value storage units  72  and  76 , first and second comparison units  73  and  77  that respectively output periods that are greater than the first and second threshold values of the output of the digital filter  71  as pulse waves, first and second pulse width calculation units  74  and  78  that calculate pulse widths from the output pulses of the first and second comparison units  73  and  77 , and a pulse-width control unit  75 , which allows the pulse-width calculating operations of the second pulse width calculation unit  78 , only within a period in which the output of the digital filter  71  is greater than the first threshold value, that is, only during a period in which the first pulse width calculation unit  74  is in operation based upon the output of the first comparison unit. Moreover, the pulse-width calculation unit  74  is designed so as to output an operation signal to the pulse-width control unit  75  during its operation. Here, the selection unit  79  is constituted by analog switches, the first and second threshold value storage units  72  and  76  are constituted by resistors, the first and second comparison units  73  and  77  are constituted by comparators, the first and second pulse width calculation units  74  and  78  are constituted by counters, and the pulse width control unit  75  is constituted by gates, respectively.  
         [0000]     Operations of the Analyzer for Particle Components in Urine  
         [0029]     Referring to FIGS.  1  to  5  and FIGS.  6  to  9 , the following description will explain the operations of the analyzer for particle components in urine in accordance with the present embodiment. First, the user inserts the suction pipette  11  shown in  FIG. 1  into the specimen container  13 , and presses the start switch  12 . Thus, urine inside the specimen container  13  is sucked through the suction pipette  11 , and subjected to a fluorescent-dyeing process, and after having been diluted, the resulting urine is transferred to the reaction chamber  48  (see  FIG. 3 ). In parallel with the transferring process of the urine, respective operations of the fluid system shown in  FIG. 3  are carried out.  
         [0030]     In  FIG. 3 , first, a washing process is carried out. In this washing process, first, the valves  41  and  50  are opened so that a sheath liquid is delivered from the sheath liquid chamber  42  storage the sheath liquid by a pressure P that is applied from the pressure device  43 , and discharged into the waste chamber  45  through the valve  41 , the fixed-amount syringe  44  and the nozzle  6 , and also discharged into the waste chamber  45  through the valve  50  and the cell  1 , and after a lapse of a predetermined period of time, the valves  41  and  50  are closed. Consequently, the fixed-amount syringe  44 , the nozzle  6 , the cell  1  and the routes thereof are washed by the sheath liquid.  
         [0031]     Next, measuring processes are carried out. In these processes, first, the valves  46  and  47  are opened, and urine that has been treated by a reagent, that is, a sample fluid is sucked from the reaction chamber  48  preserving the sample fluid by a negative pressure of the suction device  49  so that, when the path between the valve  46  and the nozzle  6  has been filled with the sample fluid, the valves  46  and  47  are closed. Next, when the valve  50  is opened, the sheath liquid is delivered from the sheath liquid chamber  42  to the cell  1  by a pressure of the pressure device  43 , and discharged into the waste chamber  45 .  
         [0032]     Next, when the valve  41  is opened, the pressure P applied from the pressure device  43  is also transmitted to the tip of the nozzle  6  through the fixed-amount syringe  44  so that at the tip of the nozzle  6 , the pressure of the sheath liquid outside the nozzle is balanced with the pressure of the sample fluid inside the nozzle. Therefore, when the piston  44   b  of the fixed-amount syringe  44  is driven by the motor  44   a  in this state, the sample fluid, located between the valve  46  and the nozzle  6 , is smoothly discharged from the nozzle  6  to the orifice section, and thinly narrowed by the sheath liquid and allowed to pass through the orifice section, and then discharged into the waste chamber  45  together with the sheath liquid.  
         [0033]     Upon completion of the driving operation of the piston  44   b  of the fixed-amount syringe  44 , the measuring processes are completed.  
         [0034]     Next, the motor  44   a  is reversely rotated so that the piston  44   b  is pulled back, and the fixed-amount syringe  44  is returned to the initial state, and since the valves  41  and  50  are maintained in the opened state during this period of time, the above-mentioned washing process is carried out so as to prepare for the next measuring processes. Here, the valve  57  is opened and closed on demand so as to discharge the waste from the waste chamber  45 .  
         [0035]     Moreover, in the above-mentioned measuring processes, in the detection unit  68  shown in  FIG. 4 , a light beam, released from the laser diode  21 , is directed to the orifice section of the sheath flow cell  23  through the collimate lens  22 .  
         [0036]     With respect to side scattered light and side fluorescent light emitted from particles in the sample fluid passing through the orifice section, the side scattered light is made incident on the photomultiplier  36  through the condenser lens  27  and the dichroic mirror  28 , while the side fluorescent light is made incident on the photomultiplier  31  through the condenser lens  27 , the dichroic mirror  28 , the filter  29  and the pin-hole plate  30 .  
         [0037]     A side scattered light signal released from the photomultiplier  36  and a side fluorescent light signal released from the photomultiplier  31  are respectively amplified by amplifiers  33  and  34 , and inputted to the pulse width calculation unit  62  shown in  FIG. 5 .  
         [0038]     The particle components in urine that are subjects to be classified in the present embodiment include cast, glass cast, white blood cell, red blood cell, bacteria, epithelial cells (single substance) or the like, and, in particular, since a pathologic cast contains a number of contents, the pathologic cast that appears in the case of a disease can be classified from cast that also appear during a normal state, depending on the number of the contents. For example, glass cast containing no contents and cast, each containing one or two contents, are classified into cast that appear during a normal state, while cast, each containing three or more contents, are classified into the pathologic cast that appear in the case of a disease. Here, those cast, each containing three or more white blood cell, are referred to as white blood corpuscle cast, and those cast, each containing three or more red blood cell, are referred to as red blood corpuscle cast.  FIG. 7 ( a ) is a top view of a cast of size L 1 , which contains one content (white blood corpuscle) of size L 2 , and  FIG. 7 ( b ) is a top view of a cast of size L 1 , which contains three contents of respective sizes of D 1 , D 2  and D 3 . The electric signal waveforms (output waveforms of amplifier  34  or  33  in  FIG. 4 ) of the side fluorescent light or the side scattered light of these cast are respectively indicated by  FIG. 6 ( a ) and  FIG. 6 ( b ). In other words, a pulse width PW 1  corresponding to a portion greater than the first threshold value Th 1  of the waveform of  FIG. 6 ( a ) is directly proportional to size L 1  of the cast of  FIG. 7 ( a ), and a pulse width PW 2  corresponding to a portion greater than the second threshold value Th 2  is directly proportional to size L 2  of the content of  FIG. 7 ( a ). Moreover, a pulse width PW 1  corresponding to a portion greater than the first threshold value Th 1  of the waveform of  FIG. 6 ( b ) is directly proportional to size L 1  of the cast of  FIG. 7 ( b ), and pulse widths W 1 , W 2  and W 3  corresponding to portions greater than the second threshold value Th 2  are directly proportional to sizes D 1 , D 2  and D 3  of the three contents of  FIG. 7 ( b ), respectively.  
         [0039]     In the pulse width calculation unit  62  shown in  FIG. 5 , either one of signals obtained from the amplifiers  34  and  33  of the detection unit  68  of  FIG. 4  is selected by the selection unit  79  (as to which of them should be selected, a determination is preliminarily set in the operation unit  61 ). The selected waveform is filtered by the digital filter  71 , and inputted to the first and second comparators  73  and  77  so that the resulting waveforms are respectively compared with the first and second threshold values Th 1  and Th 2  outputted by the first and second threshold value storage units  72  and  76 . Based upon the results of comparisons, the first and second pulse width calculation units  74  and  78  calculate the respective pulse widths.  
         [0040]     In other words, when the output signal waveform of the digital filter  71  has a signal waveform shown in  FIG. 6 ( a ), the first and second pulse width calculation units  74  and  78  respectively calculate the first pulse width PW 1  corresponding to the first threshold value Th 1  and the second pulse width PW 2  corresponding to the second threshold value Th 2  that is greater than the first threshold value Th 1 . Moreover, when, as shown in  FIG. 6 ( b ), one signal waveform has a plurality of pulse widths W 1 , W 2  and W 3  corresponding to the second threshold value Th 2 , the second pulse width calculation unit  78  calculates a total sum of a plurality of the pulse widths, that is, (W 1 +W 2 +W 3 ), as the second pulse width PW 2 , by the instruction of the pulse width control unit  75 . The data, such as the first and second pulse widths PW 1  and PW 2 , thus calculated, are stored in the data storage unit  63  shown in  FIG. 2 .  
         [0041]     The dispersion drawing forming unit  65  of the particle classifying unit  64  shown in  FIG. 2  reads data from the data storage unit  63 , and forms a dispersion drawing based upon the first and second pulse widths PW 1  and PW 2  to classify the particles, and displays the results thereof on the display operation unit  67 .  
         [0042]     Referring to a flow chart shown in  FIG. 11 , the following description will explain the classifying flow of particle components in urine by the control unit  69  of the analyzer for particle components in urine. First, at step S 1 , a CPU  80   a  of the control unit  69  in the analyzer for particle components in urine reads the first pulse width PW 1  and the second pulse width PW 2  calculated by the pulse width calculation unit  62  from the RAM  80   c  (data storage unit  63 ). Next, at step S 2 , based upon the first pulse width PW 1  and the second pulse width PW 2  thus read, the CPU  80   a  forms a two-dimensional dispersion drawing. Next, at step S 3 , as shown in  FIGS. 8 and 9 , based upon the resulting two-dimensional dispersion drawing, the CPU  80   a  classifies particle components in urine into cast and the other components (white blood cell or epithelial cells (single substance)), and then finely classifies the cast into pathological cast, cast and glass cast. Next, at step S 4 , the CPU  80   a  displays the results of classifications (see  FIGS. 8 and 9 ) of the particle components in urine together with the two-dimensional dispersion drawing on the display operation unit  67 ; thus, the processes of the classifying flow of the particle components in urine are completed.  
         [0000]     Example of Measurements by the Analyzer for Particle Components in Urine  
         [0043]     The following description will discuss an example of measurements carried out by this analyzer for particle components in urine. Human urine was used as a specimen; an aqueous solution containing HEPES, NaCl, EDTA-3K and NaOH was used as a diluent; an ethylene glycol solution containing a dye “NK-529” made by Nippon Kanko K. K. was used as a dyeing solution; and a Bactsheath MSE-900A made by Sysmex Corporation was used as the sheath liquid. Then, measurements were carried out, and  FIGS. 8 and 9  show an example of a two-dimensional dispersion drawing, which has been formed by the dispersion drawing forming unit  65 , and is displayed on the display operation unit  67 .  
         [0044]      FIG. 8  is a graph in which the pulse widths PW 1  and PW 2  of a side fluorescent light signal outputted from the photomultiplier  31  of  FIG. 4  are respectively plotted on the X-axis and Y-axis, and  FIG. 9  is a graph in which the pulse widths PW 1  and PW 2  of a side scattered light signal outputted from the photomultiplier  36  of  FIG. 4  are respectively plotted on the X-axis and Y-axis.  
         [0045]      FIGS. 8 and 9  indicate that particle components contained in urine can be clearly classified into white blood cell or epithelial cells (single substance), pathological cast that appear in the case of a disease (cast, each containing three or more contents), cast that appear in a normal state (cast, each containing one to two contents) and glass cast (cast containing no contents). Moreover, as indicated by two-dimensional dispersion drawings shown in  FIGS. 8 and 9 , the particle components contained in urine are classified by using demarcation lines.  
         [0046]     In the above-mentioned embodiment, when a single electric signal waveform has a plurality of pulse widths corresponding to the second threshold value, the pulse width calculation unit calculates the total sum of a plurality of the pulse widths as the second pulse width so that, with respect to the pulse widths corresponding to a pathological cast, that is, a cast containing a plurality of contents, the total sum is calculated as the second pulse width. Therefore, since the second pulse width of the pathological cast becomes greater in comparison with the cast also observed in a normal state, it becomes possible to finely classify the cast into those that also appear in a normal state and those pathological cast.  
         [0047]     In the above-mentioned embodiment, the particle components contained in urine are displayed by using demarcation lines on the two-dimensional dispersion drawing so as to be recognized; however, the colors of dots plotted on the two-dimensional dispersion drawing may be made coincident with the particle components to be classified. For example, dots corresponding to white blood cell or epithelial cells (single substance) may be displayed as blue dots, dots corresponding to pathological cast (cast that appear in the case of a disease) may be displayed as red dots, cast (cast that appear in a normal state) may be displayed as yellow dots, and glass cast (that contain no contents, and appear in a normal state) may be displayed as green dots.  
         [0048]     In the above-mentioned embodiment, the pulse width has been calculated by using the pulse-width calculation unit  62  having an electric circuit configuration; however, the pulse width may be calculated on a software basis by using the control unit  69  constituted by microcomputers.  
         [0049]     In the above-mentioned embodiment, the pulse width is calculated by using side fluorescent light or side scattered light emitted from particles so that cast are classified; however, the pulse width may be calculated by using high-angle scattered light emitted from particles so as to classify cast.  
         [0050]     In the above-mentioned embodiment, as shown in  FIG. 5 , side scattered light from particles in urine is detected by a photomultiplier tube  36  from the orifice section of the sheath flow cell  23  illuminated by the laser diode  21 , and side fluorescent light from the particles is detected by a photomultiplier tube  31 . Based upon the detected signals, the particles are classified. In place of this mode, an image-pickup element such as a CCD may be placed on the light axis of a laser diode  21  with the orifice section of the sheath flow cell  23  being interpolated in between, and by analyzing a cast image picked up by the image-pickup element, the cast may be classified into pathological cast (cast that appear in the case of a disease), cast (cast that appear in a normal state) and glass cast (cast that contain no contents, and appear in a normal state).  
         [0051]     In the above-mentioned embodiment, the two-dimensional dispersion drawing is formed based upon the first and second pulse widths so that the particles are classified, and the results are displayed; however, after classifying the particles based upon the first and second pulse widths, the two-dimensional dispersion drawing is formed so that the results of classifying processes may be displayed.