Among his seminal contributions to setting research paradigms in

Among his seminal contributions to setting Veliparib FDA research paradigms in memory, he introduced

what would later be called “nonsense syllables”; today they are often termed consonant-vowelconsonant (CVC) trigrams. This methodology helped identify language-free learning characteristics (although it was later found that people do assign meaning to nonsense syllables). The work carried out in the tradition of Ebbinghaus (see 7) has helped shape our understanding of memory, especially more complex verbal and associative memory. For example, it has established the distinction between recognition and recall8 indices of memory, the former relating to the ability to judge whether Inhibitors,research,lifescience,medical the present Inhibitors,research,lifescience,medical stimulus (or experience) is “old” or “new” and the latter to the ability to recount the details of the stimulus. They investigated the veracity and distortions of memory traces and uncovered interference effects such as retroactive and proactive inhibition of memory associated with interfering events. Dimensions of memory The study of

memory has been characterized by evolving conceptions and methodologies in which competing distinctions have been Inhibitors,research,lifescience,medical emphasized over the years. The initial emphasis has been on associative learning and memory and the competing and, eventually, complementary paradigms of classical and operant conditioning have yielded information on the conditions and time course of the ability of organisms to learn new associations and retrieve acquired information. These initial efforts were developed without much attention to the Wortmannin DNA-PK neurological

or neuropsychological literature Inhibitors,research,lifescience,medical on memory. The young and ambitious science of behavior was firmly convinced that behavioral science could be erected without reference to its physical organ, the brain. Physiological measures were obtained as proxies for arousal, but theories did not consider neuroscience evidence as being of much relevance Inhibitors,research,lifescience,medical to the theoretical articulation of memory. This situation has changed with advances in clinical and basic neuroscience. Clinical neuroscience has presented a series of highly informative cases and increased sophistication in documenting clinical-pathological correlations in routine cases. For example, the case of HM, who underwent bi-hippocampal Drug_discovery dissection and lost the ability to learn new information while retaining memories acquired prior to surgery, brought into sharp focus the role of the hippocampus in new learning.9, 10 Studies of patient populations with memory deficits related to seizure disorders, dementing disorders, and substance-use disorders have further identified distinct networks related to aspects of memory. At the same time, the advent of neuroimaging has opened up new avenues for probing memory processes in healthy and clinical populations.

At each center we used

several interventions: 1) Catheter

At each center we used

several interventions: 1) Catheters could only be placed by those who were trained, certified, and had performed enough procedures to maintain competence. Often, simulation was used in initial training. 2) All catheters were placed using five barrier precautions, using standardized line kits. 3) Time outs and documentation were standardized. 4) Inhibitors,research,lifescience,medical Vigorous efforts by the leadership and clinical thought-leaders assured that these measures were performed every time, with every line. 5) Because we believed that catheters placed outside of our hospitals were not up to our standards, all such catheters were removed within hours of the patient’s arrival. As figure 2 shows, at BIDMC these measures reduced central line infection 9-fold, and the improvements have been maintained for years since the interventions began. UPMC and other hospitals in Pittsburgh participated in a joint effort to eliminate these infections; the results were reported in Morbidity and Mortality Weekly Reports under the title “Elimination of central line infections: Pittsburgh”. Inhibitors,research,lifescience,medical More recently, a collaborative Inhibitors,research,lifescience,medical effort across the state of Michigan has resulted in sharp reductions in central line infections state-wide.9,10 Figure 2 Central line

infection rate in ICUs (CLABSI) by quarter, plotted on the selleckchem Axitinib ordinate as infections per thousand ICU patient days. FY refers to fiscal year. VENTILATOR-ASSOCIATED PNEUMONIA Endotracheal tubes provide ready access for mouth flora to enter the lung, often resulting in pneumonia. A large body of evidence has shown that adoption of several measures, including elevation of the head of the bed to 30 degrees, Inhibitors,research,lifescience,medical daily awakening of sedated ventilator patients, and frequent assessment of ability to remove the endotracheal tube, reduces the rate of ventilator-associated pneumonia (VAP).11 At both UPMC and BIDMC Inhibitors,research,lifescience,medical the ventilator bundle was adopted and performed on every patient, every day. The rate of VAP fell 10-fold with adoption of the bundle and

has remained at this new lower level for the past 2 years. With the adoption of these and other quality improvement measures, length Carfilzomib of stay in the ICUs fell 20%, permitting the same number of ICU beds to care for 20% more patients. This obviated the need to build an additional ICU to care for increasing ICU volume. Moreover, mortality in the ICU population fell 12%, so that for every 40 patients cared for in the ICUs, one less patient died. Since we care for 6,000 ICU patients per year, this means we now avoid deaths in some 150 patients per year. REDUCING IN-HOSPITAL CARDIOPULMONARY ARRESTS Retrospective forensic chart studies of patients who have undergone cardiopulmonary arrests reveal that up to 80% of cardiopulmonary arrests are preceded by some indication of physiologic Belinostat cost instability, ranging from high fever to high or low pulse, to high or low respiratory rate, to loss of mental status, to marked nursing concern (reviewed in 12,13).

4% vs 4 7%; p<0 007), but were less likely than pediatric patien

4% vs. 4.7%; p<0.007), but were less likely than pediatric patients to receive IV clindamycin (4.6% vs. 15.7%; p<0.001). Among discharged patients, trimethoprim-sulfamethoxazole (TMP-SMX), clindamycin, and cephalexin were kinase inhibitor Wortmannin prescribed commonly. 25.3% of all SSTI patients received an oral antibiotic in the ED, and 80.8% of patients discharged received an antibiotic Inhibitors,research,lifescience,medical prescription. Adult SSTI patients were more likely than

pediatric SSTI patients to be prescribed oral TMP-SMX (59.1% vs. 37.2%; p<0.001) at ED discharge. Of those prescribed TMP-SMX, adults were more likely than children to be also prescribed oral cephalexin (53.8% vs. 34.5%; p<0.001). Microbiologic data Table 2 summarizes the results of microbiologic cultures by age group among ED patients with cultured infections. S. aureus comprised the majority of culture isolates, and was more common in pediatric patients, Inhibitors,research,lifescience,medical while mixed flora was more common among adults than among children. Of

S. aureus isolated from CA-SSTIs, 60.4% was categorized as MRSA, with similar proportions in adults and children (60.9% vs. 59.2%; p<0.84). Table 2 Microbiologic culture results from emergency department (ED) Inhibitors,research,lifescience,medical patients with community-acquired skin & soft tissue infections Table 3 depicts the antibiotic susceptibilities among S. aureus isolated from presumed community-acquired purulent infections, comparing the resistance in these ED-acquired SSTI cultures against the resistance reported for MRSA and MSSA on the antibiogram distributed by the hospitals’ microbiology laboratory for S. aureus from all sources in 2010. Table 3 Antibiotic Resistance Among Staphylococcus Inhibitors,research,lifescience,medical aureus Isolated from skin and soft tissue

infections (SSTIs) in the emergency department Discordance of antibiotic therapy with culture results Table 4 compares antibiotic treatment with culture results among SSTIs for which both selleck chemical antibiotics were prescribed and cultures obtained. Clinicians using single antibiotics (anti-MRSA [Table 4A] or anti-MSSA [Table 4B]) used monotherapy that accurately targeted the resultant cultured pathogen accurately 39.3% of the time Inhibitors,research,lifescience,medical (ranging from 35-52% depending on age and treatment strategy). Anacetrapib Cultured SSTIs from 100% of pediatric patients and 67.8% of adult patients treated with multi-drug “double coverage” (Table 4C) grew only Staphylococcus. Table 4 Empiric antibiotic treatment and targeted organisms in microbiologic culture Table 5 displays the univariable logistic regression analyses investigating demographic and clinical correlates of coverage of the resultant pathogen with the chosen antibiotic regimen, “double coverage” antibiotic usage, and discordance of empiric MRSA therapy (use of anti-MRSA antibiotics in the absence of MRSA, or vice versa). Table 5 Logistic models to identify factors associated by univariate analysis with coverage of the isolated organism by the antibiotic prescribed (A), treatment with multiple antibiotics (“double coverage”) (B), and discordant anti-mrsa therapy …

175 In agreement with the predictions of this “synaptic homeostas

175 In agreement with the predictions of this “synaptic homeostasis hypothesis” of sleep,176 a recent study showed that in healthy humans prolonged wakefulness is associated with significant changes in the state of cortical circuits involving a steady increase in the excitability of human cortical circuits that is rebalanced during sleep.177 These effects have been related with the circadian rhythms of glutamatergic Inhibitors,research,lifescience,medical neurotransmission and with increased synaptic weights in animal models,178 thus supporting the hypothesis

that these mechanisms could provide a new basis in conceptualizing the link between chronotherapeutics and brain homeostasis in bipolar depression. Conclusion In conclusion, chronotherapeutics has now been Inhibitors,research,lifescience,medical proven to be a powerful

clinical instrument for the treatment of depression in everyday clinical practice. Rapidity of effects and lower rates of switch into mania with sellckchem respect to available antidepressant drugs make chronotherapeutic combinations a first-choice option for the hospital treatment of patients with a major depressive episode in the course of bipolar disorder. Antidepressant efficacy in nearly one half of Inhibitors,research,lifescience,medical drug-resistant patients makes it mandatory for the clinician to prescribe these treatments to these difficult-to-treat patients. Single techniques, such as light therapy, can be easily prescribed to outpatients in combination with the usual antidepressant drug treatments. In all cases, chronotherapeutic techniques should be combined with mood-stabilizing treatments, such as lithium salts, which are the mainstay of the Inhibitors,research,lifescience,medical long-term psychiatric management of bipolar disorder and which can enhance, and sustain the acute antidepressant Inhibitors,research,lifescience,medical effects of chronotherapeutics.
Rarely in the history of Western thought has a concept inspired as much reflexion as that of time. The humanities, as well as the

DAPT secretase mw various fields of research making up natural science, life science, social science, cognitive science, and neuroscience all have fundamental things to say about time, or temporality, and its different accepted forms (duration, instant, moment, cycle, rhythm, flux, period, era, etc). Given this astounding wealth of scholarship, it is essential to define precisely one’s object of study. This contribution deals with collective representations of time and the academic work they have elicited in the field of social science. GSK-3 Being an anthropologist, I provide an overview of the theories that have arisen and been developed and discussed in this field, but I also consider the work of sociologists, social theorists, and historians. This contribution is based on the assumption that the construction of time in social processes of action and thought has as great an impact on individual representations and perceptions as, say, brain rhythms, light cycles, or the phenomenon of aging.

De Haas et al , reported fewer overall complications with simulta

De Haas et al., reported fewer overall complications with simultaneous colorectal selleck chemicals Vismodegib resection and liver metastasectomy (11% vs. 24%, respectively); but mortality rates were similar when compared to staged resections (45). Other studies have reported similar rates for both morbidity and mortality with simultaneous resection compared to staged resections (46-48). Despite these results, some centers still support a staged resection, with initial colorectal resection followed by future interval/delayed hepatic resection (35,49,50). Inhibitors,research,lifescience,medical The management

of metachronous CRLM disease is generally straightforward and involves initial colorectal resection and later resection Inhibitors,research,lifescience,medical of CRLM. Treatment algorithms for patients with CRLM have evolved

because of improved response rates with the addition of targeted agents to treatment regimens. Multiple trials have been shown to significantly increase response rates when adding bevacizumab or cetuximab to irinotecan or oxaliplatin backbone regimens (51-54). For example, cetuximab was evaluated in the phase II multi-center CELIM trial. Patients with unresectable CRLM were Inhibitors,research,lifescience,medical randomized to receive cetuximab with either FOLFOX6 or FOLFIRI (52). The ORR was 68% in the FOLFOX6 arm and 57% in the FOLFIRI arm (52). R0 liver resection was subsequently performed in 20 of 53 (38%) patients in the cetuximab/FOLFOX6 group and in 16 of 53 (30%) patients in the cetuximab/FOLFIRI group. The increases in ORRs have ranged between 10-30% with corresponding increased rates of hepatic resection

of 5-20% when cetuximab was combined with chemotherapy across most studies (29,52,55). Improvements in ORRs and subsequent rates of surgical Inhibitors,research,lifescience,medical resection have also been observed with bevacizumab. In the First Bevacizumab Expanded Access Trial (First Inhibitors,research,lifescience,medical BEAT), bevacizumab was added to the investigator’s choice of fluoropyrimidine-based chemotherapy for patients with CRLM (54). Of 1,914 patients, 225 were able to undergo surgery with curative intent (11.8%). Resection rates were higher in patients receiving oxaliplatin-based chemotherapy (16.1%) than in those receiving irinotecan-based chemotherapy (9.7%). Batimastat Finally, Falcone et al. reported a 66% ORR with FOLFOXIRI alone, whereas response rates with single backbone chemotherapy regimens in most trials were much lower and ORRs have generally increased with the addition of bevacizumab or cetuximab (20,21,51). Despite great improvements in response rates and resectability with standard and targeted agents, chemotherapy has the potential for liver damage and toxic side-effects that can affect surgical outcomes. Significant decreases in liver function have been described with 5-FU, oxaliplatin, and irinotecan and can contribute to increased perioperative morbidity (43,56).

Recruitment to the prospective study was assisted by in-servicing

Recruitment to the prospective study was assisted by in-servicing which helped to ensured that all of the patients who required the site parenteral sedation and mechanical restraint were recruited to the study due to staff awareness and only six were missed (Figure ​(Figure11). Main Outcomes The

primary outcome was the duration in minutes of the ABD comparing patients during the new intervention to the historical controls. Other outcomes included the requirement for additional sedation and adverse effects from the sedative medication, which includes both patient and staff incidents. Additional sedation included Inhibitors,research,lifescience,medical further sedation required to obtain initial sedation as well as re-sedation if the patient re-emerged Inhibitors,research,lifescience,medical still agitated. Re-sedation was defined as sedation after an interval exceeding one hour where no further sedation was given during that time, based on repeat sedation in a previous study[2]. Sedative related adverse effects included any

episodes of oxygen desaturation (< 90%), hypoventilation (respiratory rate < 12), requirement for airway intervention or support, arrhythmias or hypotension. Staff or patient injuries were also determined for both groups and were reported during both periods as per hospital guidelines for incident Inhibitors,research,lifescience,medical monitoring. Data Analysis Medians and interquartile ranges (IQR) are reported for all continuous variables. Percentages are reported for dichotomous outcomes with 95% confidence intervals (CI). Comparison of continuous variables between the two groups was performed using the non-parametric Mann-Whitney test. Statistical analysis was performed using Prism 5.01 (GraphPad Software Inc). Results There were 58 patients recruited Inhibitors,research,lifescience,medical during 8 month period where the new IM sedation protocol was used. These were compared to 73 historical control patients Inhibitors,research,lifescience,medical that similarly required parenteral sedation in the 8 month period prior to the

new IM protocol. Only 20 of the 73 historical controls (27%) initially received IM sedation, compared to all patients for the IM sedation protocol. Baseline characteristics for both groups are compared in Table ​Table11 and are similar except for the selleck larger proportion of males during the new protocol. Cilengitide Table 1 Baseline characteristics of the historical control patients compared to patients with the new protocol of intramuscular sedation The median duration of the ABD in patients with the new sedation protocol was 21 minutes (IQR: 15 to 35 minutes; Range: 5 to 78 minutes) compared to a median duration of 30 minutes (IQR: 15 to 50 minutes; Range: 5 to 135 minutes) in the historical controls which was significantly different (p = 0.03) [Figure ​[Figure22]. Figure 2 Box and whisker plots showing the duration of the ABD comparing historical control patients to patients with the new sedation protocol. The whiskers are the 5th and 95th percentiles, the box the interquartile range, extreme outliers are filled circles ..

Summary of current gene-finding

studies At both the techn

Summary of current gene-finding

studies At both the technical/molecular and statistical/conceptual levels, the science of gene discovery in complex disease selleck compound genetics is moving rapidly. By the time this paper is published, new developments are sure to have arisen. As is common in science in the state of rapid flux, the direction ahead is far from clear. How will the modest Inhibitors,research,lifescience,medical but hard-fought advances obtained in more traditional positional cloning and candidate gene work integrate with the new findings from GWAS? How will the commonvariant SNP-based approach inter-relate with the emerging rare-variant copy number variant findings? Will advances in phenotypic assessment or endophenotypes provide critical new insights? How will the burgeoning fields of bioinformatics, expression arrays, and proteomics

impact on our gene-finding efforts? One emerging consensus is that the field needs to move from a “gene-centric” approach toward one that considers “gene networks.” For example, many of the candidate genes discussed above are involved in glutamatergic neurotransmission, Inhibitors,research,lifescience,medical which may be an important systemic element in the etiology of schizophrenia. Although a detailed discussion of this theory is outside the scope of this summary, recent reviews of the genetic183 and neuroscience184 data and evidence from other studies highlight the positions of the gene products of NRG1, COMT, and possibly DTNBP1 among others, Inhibitors,research,lifescience,medical in the Inhibitors,research,lifescience,medical biochemical and functional pathways influencing the glutamatergic system. Many other possible networks may be involved in the etiology of schizophrenia that, if properly articulated, could aid in our gene-discovery efforts. Conclusion We have attempted in this article to review the rapidly evolving field of psychiatric Inhibitors,research,lifescience,medical genetics. In the section on genetic epidemiology,

we took a conceptual approach focusing on a range of the most interesting questions now being confronted by the field, with the goal of giving the reader a “feel” for the issues. While examining a wide range of disorders, we focused on substance use and externalizing STI 571 disorders because they clearly illustrated the points we wanted to make. In the section on gene-finding, we decided it would be more useful to “drill down” and illustrate our important themes by focusing on one disorder Cilengitide – schizophrenia. The major theme that cuts across these two sections is the complexity of the pathways from genetic variation to psychiatric and substance use disorders. Results of the last 20 years have shown that the early prior simple hypothesis of large effect genes that directly causes psychiatric illness was seriously misplaced. We now know that multiple gene variants (as well as – for at least some disorders – genomic rearrangements) are involved at the DNA level. These genetic risk factors then act and interact with each other and with the environment in a complex developmental “dance” to produce individuals at high versus low risk of illness.

Once polished, the free end of the fiber was scored and cleaved t

Once polished, the free end of the fiber was scored and cleaved to 10–12 mm in length. Custom hardware and software was designed

in order to standardize Arry-380 price the variations in output intensity and calibrate each ferrule2. An intensity calibration device (ICD; Figure ​Figure1F1F, bottom) was designed in Solidworks 2011 (Dassault Systèms Solidworks), 3D-printed on an Objet Eden 250 from FullCure 720 model resin, and painted black. A S121C silicone diode (Thorlabs) was placed within the central cavity of the ICD and connected to a PM100USB intensity meter (Figure ​Figure1F1F, top). Custom-written LabVIEW 2009 software (National Instruments, Austin, TX, USA; Figure ​Figure1G1G) steps the LED through user-defined output voltages and measures the resultant power for a defined wavelength and number of points on the S121C silicone diode. LED output power passing through the ferrule is thus correlated to the analog input voltage signal to the LED controller. The program then calculated intensity from power based on the diameter of the

fiber optic and linearly correlated to the voltage input. This standardized the output of each ferrule based on intensity rather than voltage input, enabling precise stimulation at accurate intensities across all experimental subjects. Custom-written Matlab scripts then converted standard output intensities to the appropriate signal voltages for each test subject. Ferrules were attached to the patch fiber cable by means of 1.25 mm inner diameter ceramic split sleeves (Precision Fiber Products). These were reinforced by threading them through trimmed heat shrink tubing (Digi-Key, Thief River Falls, MN, USA), and subsequently heating them. These reinforced sleeves were superior to the bare split-sleeves in resisting breakage due to vigorous movement of some subjects. This ceramic split sleeve was the most common breaking point in the connection, conveniently leaving the implanted ferrule and patch fiber cables intact. ELECTRODE ARRAYS Two electrode array configurations

Drug_discovery were used in these proof-of-concept experiments. For recording of the dorsal hippocampus while simultaneously stimulating the MS, 16-channel microwire multielectrode arrays [Tucker Davis Technologies (TDT), Alachua, FL., USA; MEA] were constructed from sixteen 33 μm diameter tungsten electrodes with polyimide insulation (Figure ​Figure1I1I). The electrodes were arranged in two rows of eight electrodes with 1 mm between rows and 175 μm of space between the electrodes within a row. Ground and reference wires were separated on the array and routed through two stainless steel wires, which were affixed to separate skull screws during the implantation surgery. The two rows were cut to different lengths, 4.0 and 3.


Credit The cover photograph was taken by William Ba


Credit The cover photograph was taken by William Banner, MD. Dr. Banner gives his permission for use.
A 70-year-old man with an 8-month history of left posterior thigh and leg pain was admitted to our Emergency Department after a fall during a gym session. He presented with a moderate pelvic and head trauma. A physical examination showed only tenderness upon palpation and percussion of the lumbar and sacral spine. Plain radiographic examinations of spine, pelvis Inhibitors,research,lifescience,medical and chest were interpreted as normal. The patient had no medical or surgical history other than essential hypertension. A few hours after admission, he became very confused and agitated. A cerebral computed tomography scan did not show either vascular lesion or cerebral contusion but fat droplets in the lateral ventricles (Figure ​(Figure1A).1A). A further investigation with CT scan of the spine revealed a fractured sacrum extending into a ruptured perineurial cyst (Figure ​(Figure2A).2A). A cerebral and spinal magnetic resonance image (MRI) scan confirmed Inhibitors,research,lifescience,medical these findings (Figures ​(Figures1B,1B, 2B-C) and we suspected that fatty bone marrow had migrated from sacral fracture to the brain in an unusual Inhibitors,research,lifescience,medical way: a dural breach at the Tarlov cyst. Surgical treatment was not carried

out because of the fractured sacrum. The patient remained under medical observation and fully recovered within three weeks. Two months after Inhibitors,research,lifescience,medical discharge, the patient had no complaints and had a normal physical neurological examination. Figure 1 Head CT-scan and MRI image. A. Post contrast head CT-scan:

fat droplets in the frontal horns of the lateral ventricles (white arrows). B. Sagittal T1-weighted head MR image: fat droplets disseminated in the subarachnoid spaces (white arrows). Figure 2 Sacral cyst CT-scan and MRI image. A. Axial sacral CT-scan: left sacral fracture extending to the S2 radicular cyst (presence of a contralateral cyst at the same level). B. Sagittal T2-weighted sacral MR image: S2 Inhibitors,research,lifescience,medical radicular cyst with two liquids: cerebrospinal … Discussion Tarlov cysts were first described in 1938 as an incidental finding at autopsy of fillum terminale [2]. Then Tarlov described cases of symptomatic (low back pain) perineurial cyst and recommended their surgical removal with sacral laminectomy and excision of Entinostat the cyst along the nerve root [3]. More recently, Paulsen et al [4] reported an incidence of Tarlov cysts which accounted for 1% of all back pains reported. They are more contain common in females [4]. The usual clinical presentations are pain in the lower back, sciatica, coccydynia or cauda equina syndrome. Usually, pain is intermittent and most frequently exacerbated by standing, walking and coughing. Tarlov’s perineurial cysts were initially described in the posterior sacral or coccygeal nerve roots [3].

Evidently, in vivo and many other sensing applications would bene

Evidently, in vivo and many other sensing applications would benefit from the fiber material being humidity insensitive. TOPAS is photosensitive and thus TOPAS FBG sensors can be fabricated [53,55], and TOPAS is highly transparent in the THz regime, where PMMA is extremely lossy [56�C58].In contrast to PMMA, TOPAS is chemically inert and thus biomolecules are not easily immobilized onto it. However, commercially available anthraquinone (AQ) photolinkers (see can attach to the TOPAS surface when activated by UV light and can subsequently accept sensor layers. This concept was used to develop the first flourescence-based TOPAS mPOF antibody biosensor, which had a reasonable selectivity [21,22]. Here we for the first time take full advantage of the chemical inertness of TOPAS and the AQ-linker technology and present the first fluorescence-based serial fiber-optical biosensor capable of selective detection of two different antibodies with a single fiber.2.?The Optical Fiber SensorIn this first proof-of-concept we do not focus on optimi
Each step of the imaging and signal processing has been investigated to find the possible error factors [4�C6]. Simulation for two types of product has been done to estimate the degree of influence of the various error factors.3.1. Distance Deviation between Entrance Slit and Code DialThe encoded rows on code dial are etched according to the rule of y = H tan(��), where H is the distance between entrance slit and code dial. The ideal value of the distance is H, but there is always a deviation ��H between ideal value and actual value due to limited manufacturing accuracy. Let y be the position of sunlight on the code dial when incident angle (i.e., measurement angle) is ��. The output angle of ESS can be expressed as ���� = atan(y/H), while the actual incident angle of sunlight is �� = atan(y/H��), which cause error as shown in Figure 2.Figure 2.Deviation of distance between entrance slit and code dial.Measurement errors caused by distance deviation ��H for two types of product (designated as A and B) were analyzed by simulation. The distance H is 4.124 mm for product A and 6.584 mm for product B. The simulation is done under the following conditione: distance deviation ��H is ��2 microns, and the range of measurement angle is (?62��~62��). Figure 3 shows the simulation result for product A.Figure 3.Measurement error caused by distance deviation ��H.Simulated results are as follows:(1)Measurement errors caused by distance deviation ��H will increase when the distance between the entrance slit and code dial decreases or the incident angle increases.(2)For Product A, measurement error will exceed 0.015�� when the distance deviation exceeds two micron, as shown in Figure 3. For Product B, measurement error will exceed 0.008�� when the distance deviation exceeds two microns.