Including Time Interval Research Articles

Passive Robustness in Milk Manufacturing Unit with Time Constraints

This paper deals with the robustness of a milk manufacturing workshop including time interval constraints. In such systems operation times are included between a minimum and a maximum value. Weighted Marked Graphs are used for modeling. We recall some results proposing to transform Weighted Marked Graphs into Marked Graphs, in order to obtain a model, which can be used to apply some robustness results on a milk manufacturing unit. In the last part, a computing algorithm, of a lower bound of the maximal time disturbances allowed in a given point of the milk manufacturing workshop, is applied. The industrial example shows how results of P-time Model Graph can be extended to Weighted Marked Graphs.

Nausea and Cough May Be Inducing Reflux in Some Patients

Purpose: Introduction: In multichannel intraluminal impedance and pH (MII-pH) monitoring, symptom association with reflux is an important part of the diagnostic component of the test. This was traditionally looked at by using either symptom index (SI), or Symptom association probability (SAP). The SI only takes into consideration reflux occurring before a symptom, while SAP takes into consideration a 2 minute period around a reflux episode. Aim: To assess frequency occurrence of MII-pH detected reflux episodes before and after a reported symptom. Methods: Retrospective review of 126 consecutive adult patients (88 females; 40 males; means age 50.2 years). Data collected between 11/2006 and 02/2009. Presence of reflux episodes within 5 minutes of any reported symptom was counted and then divided by total number of the same symptom for each patient. This allowed us to calculate an SI for 5 minutes before and 5 minutes after each symptom. Results: The table below shows p values comparing the 2 different symptom indices: 5 minutes before and 5 minutes after the symptom, This data shows us that reflux episodes occur more frequently before than after these symptoms: heartburn, indigestion, throat clearing, regurgitation and chest pain. However, for cough and particularly nausea, there is no statistically significant difference for the likelihood of reflux episodes to occur before rather than after these symptoms.TableConclusion: Nausea and possibly even cough could be symptoms both causing reflux and due to it. This data suggests that including time interval after a symptom in analyzing symptom association may be error inducing.

Reoperative thyroidectomy for benign thyroid disease

Subtotal thyroidectomy for benign thyroid disease (BTD) may lead to delayed recurrence, thus necessitating reoperative surgery. We describe our experience with reoperative thyroidectomy for BTD and recommendations for definitive primary management. Patients undergoing thyroid surgery between 2003 and 2007 by a single surgeon were prospectively assessed. Numerous clinical parameters were evaluated, including time interval between primary and reoperative surgery and complications. In all, 321 thyroidectomies were identified: 45 were reoperative and 22 were related to BTD after primary surgery done elsewhere. Median interval between the primary and reoperative procedure was 8.5 years. No recurrences followed total thyroidectomy or total thyroid lobectomy. There were no cases of permanent or transient recurrent laryngeal nerve (RLN) injury related to reoperative surgery. There was 1 case of transient hypocalcemia. Although reoperative thyroidectomy can be performed safely in the hands of experienced surgeons, a thorough initial surgical procedure should obviate the need for exposure to this additional risk.

Establishing a point of departure for risk assessment using acute inhalation toxicology data

A simple method is presented for estimating a non-lethal level for inhalation toxicity studies. By reviewing 209 LC 50 studies representing 96 chemicals that also reported a non-lethal level, it has been shown that taking 1/3 of the LC 50 is a conservative estimate for a non-lethal exposure level. This approach was also compared to studies with LC 01 and BMCL 05 calculations. In the 38 studies that reported either of these values, again taking 1/3 of the LC 50 provided a more conservation estimate for the non-lethal threshold. The studies included time intervals from 5 min out to 8 h and utilized multiple species such as the rat, mouse, hamster, guinea pig and dog. In all but 13 cases, taking 1/3 of the LC 50 provided a more conservative estimate for a non-lethal exposure level compared to the experimentally observed value. In all but one of the 13 cases, the higher values were consequences of the selection of the exposure levels.

The timing of enterostomy reversal after necrotizing enterocolitis

Background/Purpose Newborns undergoing surgery for necrotizing enterocolitis (NEC) often require a stoma. The study purpose is to determine if the timing of stoma closure impacts the postoperative course. Methods After obtaining institutional review board approval, records of patients with NEC who received a stoma between 2003 and 2007 at 2 pediatric institutions were reviewed. Data collected included time interval between stoma creation and closure, indication for closure, postoperative complications, time to feeds, and length of neonatal intensive care unit and hospital stays. For analysis purposes, patients were divided in 2 groups: 1, stoma closed within 10 weeks; and 2, stoma closed more than 10 weeks after construction. Results There were 37 patients: 13 in group 1 and 24 in group 2. Group 1 babies were ventilated longer postoperation (7.69 vs 1.08 days, P = .0006). They required total parenteral nutrition for more days (51.62 vs 16.30 days, P = .0486). Group 1 patients took longer to reach full po (19.08 vs 7.86 days, P = .027), and they had a longer length of stay postreversal (113.08 vs 31.32 days, P = .0373). No differences were observed in survival rates or anastomotic complications. Conclusion The timing of stoma reversal significantly impacts the postoperative course after NEC. Unless seriously indicated, stoma closure should be deferred until at least 10 weeks postcreation.

A three-dimensional finite element analysis of two/multiple shots impacting on a metallic component

This paper describes a three-dimensional dynamic finite element analysis of two/multiple shots impacting on a metallic component. The model is validated against a published numerical study. An extensive parametric study is conducted to investigate the effect of shot impacting with overlap on the resulting residual stress profile within the component, including time interval between shot impacts, separation distance between the impacting points, and impacting velocity of successive shots. Several meaningful conclusions can be drawn regarding the effect of shot impacting with overlap.

Factors Associated with Hurricane Preparedness: Results of a Pre-Hurricane Assessment

Previous studies of hurricane preparedness have generally used indirect measures to ascertain household preparedness, including time intervals between preparation and hurricane landfall and past evacuation. This study sought to directly measure hurricane preparedness by asking residents of a high-risk coastal North Carolina county to report whether their household had an evacuation plan and a disaster supply kit with at least 3 days of food and water for each family member and pet as recommended by the American Red Cross. The survey was conducted six weeks prior to the start of the 2007 Atlantic hurricane season. Past hurricane experience increased the likelihood of a household having a disaster supply kit. However, living in multi-unit housing or a mobile home significantly decreased the likelihood of having a disaster supply kit. Past hurricane experience, past evacuation experience and anticipated evacuation under a mandatory evacuation order were important factors related to a household having an evacuation plan. Residence in a designated flood zone, demographic characteristics of the household, pet ownership, and perceived risk were not significantly related to preparedness. Public health and emergency management officials should work together to determine effective interventions that can improve personal preparedness based on factors other than personal hurricane experience.

Clinical significance of matrix metalloproteinase-2 in cancer of uterine cervix: A semiquantitative study of immunoreactivities using tissue array

Objectives. To study the expression of matrix metalloproteinase-2 (MMP-2) in cancer of uterine cervix and correlate its expression with clinicopathological parameters, recurrence and survival of patients. Methods. Twenty cervical cancer and 20 normal tissues from the same patients were collected to detect MMP-2 mRNA expression. From them, 16 cancer and 16 normal tissues were collected and added with another 64 cancer tissues to construct a 96-tissue core microarray for immunohistochemical study. We evaluated the relationships among MMP-2 immunoreactivity using semiquantitative H scores, obtained by multiplying proportion score of stained cells and their mean digital density, and clinicopathological variables, recurrence and survival in cervical cancer patients. We used univariate and multivariate analyses of all parameters for recurrence and survival, further including time interval for evaluation. Results. MMP-2 mRNA expression was higher in most of cervical cancerous tissues than normal counterparts. H score of MMP-2 was significantly higher in cancerous tissue cores than normal counterparts (median H scores: 1.5 vs. 0.3, P < 0.001). MMP-2 expression was significantly associated with parametrium invasion ( P = 0.004) and lymph node metastasis ( P = 0.015), but not with cancer recurrence, recurrence-free and overall survival rates of these patients. However, poor tumor cell differentiation and positive parametrium invasion significantly increased the recurrence and poor cell differentiation increased the risk of death. Conclusions. MMP-2 is highly expressed in cervical cancer tissues at mRNA and protein levels and associated with lymph node metastasis and parametrium invasion but not predictive of recurrence and survival in cervical cancer patients.

Establishing Arizona's Statewide Cardiac Arrest Reporting andEducational Network

Background. Only a few large cities have published their out-of-hospital cardiac arrest (OHCA) survival statistics using the Utstein style reporting method. To date, to the best of our knowledge there has been no published OHCA survival data for a state. Objective. To describe the process, benefits, andchallenges of establishing a statewide OHCA database andeducational network. Methods. Arizona's Bureau of Emergency Medical Services andTrauma System initiated a statewide, prospective, observational cohort review of all OHCA victims on whom resuscitation was attempted in the field. Emergency medical services (EMS) first care reports, voluntarily submitted by 35 departments in Arizona, were analyzed. We chronicled the development of our data-collection process along with how we obtained patient outcomes anddelivered feedback to field providers. Entry data included time intervals andnodal events conforming to the Utstein style template. Results. In data collected between January 1, 2005, andApril 1, 2006, there were 1,484 OHCAs reported, of which 1,104 were of presumed cardiac etiology occurring prior to EMS arrival. The OHCA incidence was approximately 0.44 per 1,000 population per year. In our database, bystander CPR provided an odds ratio of 3.0 for survival (95% confidence interval 1.3, 6.7). Outcomes for 1,076 patients were obtained. Thirty-seven (3.4%) of the 1,076 cardiac arrest victims survived to hospital discharge. Twenty-seven (8.6%) of the 331 ventricular fibrillation cardiac arrest victims survived to hospital discharge. Conclusion. It is feasible for a public health agency to implement a voluntary, statewide data-collection system andeducational network to determine andimprove survival from OHCA.

ROBUST DYNAMIC CONTROL OF MULTI-PRODUCT JOB-SHOPS

This paper deals with the robustness of Dynamic Discrete Event Systems including time interval constraints. It recalls to mind a method to compute the passive robustness by the decomposition of the P-time Petri Net model into four sets. The computing algorithm of a lower bound for the maximal time disturbances allowed on a given point is presented. The main contribution concerns the active robustness. An algorithm providing a global robustness new lower bound is introduced.

Tectonic controls on the late Miocene–Holocene volcanic eruptions of the Tengchong volcanic field along the southeastern margin of the Tibetan plateau

The Tengchong volcanic field, located along the southeastern margin of the Tibetan plateau, experienced multiple eruption stages since the late Miocene, including time intervals of ∼5.5–4.0 Ma, 3.9–0.9 Ma, 0.8–0.01 Ma, and younger than 0.01 Ma. These eruption stages produced different volcanic rocks, principally basaltic and basaltic-andesite series. At the same time or prior to volcanic eruptions in the Tengchong volcanic field, NE–NNE-trending rift basins and NS-striking normal faults formed during the late Miocene–Pliocene. In addition, rapid exhumation of the neighboring mountains occurred at ∼6–5 Ma constrained by apatite fission track dating and its thermochronological modeling. At present, the state of stress in the Tengchong volcanic field and its surroundings is NNE–NE-compression and WNW–NW-extension based on seismic foci mechanisms. Petrologic and geochemical data indicate that the source of the Tengchong volcanic rocks belongs to an intracontinental tectonic setting, but not a subduction or collision zone between Indian and Eurasian plates. Since the late Miocene, the dextral strike-slip motion of the Sagaing fault induced E–W-extension. The Sagaing dextral strike-slip motion might disturb the lower crust-upper mantle of the Tengchong block, resulting in the partial melting of the upper mantle which, in turn, induced volcanic eruptions characterized by mature island-arc features.

Oral misoprostol for induction of labor in prelabor rupture of membranes (PROM) at term: a randomized control trial

To compare the efficacy of two different dosages of oral misoprostol (50 and 100 microg) with control, in medical induction of labor for patients with prelabor rupture of membranes (PROM) at term. One hundred women with PROM at term were randomized to receive placebo (vitamin B6 50 mg, control), 50 microg (treatment group 1), or 100 microg (treatment group 2) of oral misoprostol every 4 h to a maximum of six doses. The main outcome measures included time interval from onset of PROM to delivery, duration of first stage of labor, and occurrence of vaginal delivery within 24 h from PROM. The time intervals from PROM to delivery were significantly reduced in both treatment groups compared to control (control, 25.1+/-10.5 h; treatment group 1, 14.5+/-6.2 h; and treatment group 2, 13.0+/-6.1 h, p<0.0001 for both). The duration of the first stage of labor was significantly shortened only in treatment group 2 compared to control (3.3+/-2.5 versus 6.2+/-3.4 h, p=0.01). Of those who delivered vaginally (93% in treatment group 1 and 97% in treatment group 2), significantly more women delivered within 24 h of PROM in the treatment group compared to the control group (50%, p<0.05). Oral misoprostol 50 microg every 4 h is safe, cheap, and as effective as 100 microg in reducing the PROM to delivery time interval and labor duration in primiparous women. The same effect is not observed in a multiparous group.

EFFICIENCY IN AN ENDOSCOPY UNIT IN A TEACHING HOSPITAL - DELAYS, PROLONGED PROCEDURES AND INPATIENT WAITING TIMES

Purpose: The need to improve efficiency in endoscopy units is receiving attention because of increased demand for screening colonoscopy. One solution is to increase the volume of endosocpic services available by efficiently utilizing existing resources. The purpose of this study was to assess efficiency in the endoscopy unit of a large tertiary care teaching hospital. Methods: A research assistant collected data prospectively over 3 months in the endoscopy unit of a 650 bed acute-care teaching hospital. The data collected on inpatient and outpatient procedures included time intervals between endoscopic procedures and procedure durations. Procedure delays (defined as time interval between procedures of >15 minutes) were determined and the reasons for them recorded. For inpatients, the number of additional days spent waiting in hosptial for endoscopic procedures was also recorded. Results: From May 16-September 5, 2003, 675 endoscopic procedures were observed in 625 patients of whom 207 (33%) were inpatients. The most common procedure performed was colonoscopy (42.1%) followed by esophagogastroduodenoscopy (36%). Overall, in 193/625 patients (30.9%), the procedures were delayed (>15 minutes between procedures). Of these, the time interval between procedures was >30 minutes in 24.4%. The delays were physician-related in 54.4% (physician was not available to start the procedure). Procedure duration was prolonged in 22% of procedures. 86/207 (41.5%) inpatients waited at least one day in hospital for their procedures. Conclusions: Procedure delays were considerable and physician unavailability contributed to these delays. Strategies to reduce procedure delays could have a favorable impact on the volume of procedures performed in the unit, thereby improving utilization of existing resources. The generalizability of these findings is not known although it is widely perceived that the delivery of endoscopic services in large tertiary care teaching hospitals may not be as efficient as in other settings. Our results support this observation. We encourage other groups to assess the efficiency in their endoscopy units.

Discovering time-interval sequential patterns in sequence databases

Abstract Sequential pattern mining, which discovers frequent subsequences as patterns in a sequence database, in an important data-mining problem with broad applications. Although conventional sequential patterns can reveal the order of items, the time between items is not determined; that is, a sequential pattern does not include time intervals between successive items. Accordingly, this work addresses sequential patterns that include time intervals, called time-interval sequential patterns. This work develops two efficient algorithms for mining time-interval sequential patterns. The first algorithm is based on the conventional Apriori algorithm, while the second one is based on the PrefixSpan algorithm. The latter algorithm outperforms the former, not only in computing time but also in scalability with respect to various parameters.

Continuous Image and Electrophysiological Recording with Real-Time Processing and Control

Collecting continuous video together with multichannel electrophysiological data and other experimental modalities requires high bandwidth and storage capacities, as well as accurate synchronization to detect correlations between different recorded events. Often, experiments are highly complex, with many variables requiring immediate analysis and feedback during the course of the experiment. In addition, output channels require real-time control with high time resolution. We have explored several approaches to a system that can perform the above functions. The design of our system considered a number of issues, including time intervals between control and acquisition events, longest continuous recording period, data transfer bottleneck considerations, file archiving and format, and real-time display and processing. To demonstrate the system, we describe an experiment for characterizing rapid evoked scattered light changes in neural tissue, in vivo, using simultaneous electronic image acquisition and electrophysiological recording.

Temporal expressiveness in querying a time-stamp--based clinical database.

Most health care databases include time-stamped instant data as the only temporal representation of patient information. Many previous efforts have attempted to provide frameworks in which medical databases could be queried in relation to time. These, however, have required either a sophisticated database representation of time, including time intervals, or a time-stamp-based database coupled with a nonstandard temporal query language. In this work, the authors demonstrate how their previously described data retrieval application, DXtractor, can be used as a database querying application with expressive power close to that of temporal databases and temporal query languages, using only standard SQL and existing time-stamp-based repositories. DXtractor provides the ability to compose temporal queries through an interface that is understood by nonprogramming medical personnel. Not all temporal constructs are easily implemented using this framework; nonetheless, DXtractor's temporal capabilities provide a significant improvement in the temporal expressivity accessible to clinicians using standard time-stamped clinical databases.

Assessment of fetal well-being in methadone-maintained pregnancies: abnormal nonstress tests.

To investigate parameters of fetal well-being (characteristics of nonstress test, NST, and antepartum fetal heart rate, FHR, patterns) and selected neonatal outcomes in pregnant women on methadone maintenance. A matched case-control study of methadone-treated women receiving prenatal and intrapartum care at a Bronx municipal hospital during 1992-1994. 102 NSTs obtained from 24 methadone-treated women after 35 weeks of pregnancy were compared to 96 NSTs from a control group (n = 24), matched for maternal age, parity, and gestational age. All NSTs were evaluated for general characteristics including time interval between initiation and achievement of reactive NST (2 accelerations > or = 15 bpm lasting for at least 15 s in a 20-min period), baseline, amplitude of fluctuation, frequency of fluctuation, accelerations and decelerations. The scoring system described by Lyons et al. was used for all NSTs. All nonreactive NSTs were followed with biophysical profile tests. The frequency of nonreactive NSTs was significantly higher for methadone-maintained women compared to controls (19.6 vs. 4.2%; p < 0.01). The average length of time to achieve reactive NST was significantly (p = 0.0016) longer for the methadone-treated group when compared to controls (35.50 +/- 20.96 vs. 14.85 +/- 9.03 min). The total score (Lyons et al.) was significantly lower (p < 0.0007) for the methadone-treated group compared to controls. Mean birth weight, Apgar scores at 1 and 5 min, meconium, and umbilical cord artery pH were not significantly different for methadone-exposed neonates compared to controls. Methadone-maintained pregnancies are significantly associated with a higher incidence of nonreactive NSTs, longer intervals to achieve reactive NSTs and lower NST scores compared to controls. This may reflect an altered response in fetal central nervous system neurotransmitters and changes in fetal behavior induced by methadone.

Randomized trial comparing preoperative versus postoperative irradiation for prevention of Heterotopic ossification following prosthetic total hip replacement: Preliminary results

Purpose: Previous in vivo data support effectiveness of preoperative irradiation in suppressing heterotopic ossification (HTO) in a rat model. A prospectively randomized, multiinstitution clinical trial to assess the comparative efficacy of preoperative vs. postoperative irradiation in preventing HTO in total hip replacement patients was undertaken. Methods and Materials: One hundred and twenty-two patients (124 hips) with significant risk factors for HTO following elective total hip replacement were randomized to receive irradiation via either preoperative (< 4 h before surgery) or “standard” postoperative (< 48 h after surgery) schedules. Single 7–8 Gy fractions were administered. Treatment volume included soft tissues between periacetabular region of pelvis and intertrochanteric portion of femur. All but nine patients had biologic fixation prostheses, the porous-coated portions of which were shielded. Radiographs of treated hips were obtained immediately and at 2 and 6 months postsurgery. Heterotopic ossification was scored according to the Brooker Grading system. Results: Ninety-eight patients are evaluable (55 preoperative, 43 postoperative) with median follow-up of 38 weeks. No significant differences were noted in the incidence of overall HTO (26% preoperative vs. 28% postoperative, p = 1.0) or clinically significant Brooker grade 3 or 4 HTO (2% preoperative vs. 5% postoperative, p = 0.58). No significant differences in treatment variables (including time interval between preoperative irradiation and surgery) were evident on comparing preoperatively treated patients forming HTO with those who did not. Conclusion: Prophylactic irradiation of the operative site within 4 h prior to elective total hip replacement appears to be comparably effective to the currently accepted postoperative treatment schedules in prevention of clinically significant HTO about the hip. This finding is of importance in terms of patient comfort, ease of treatment, and avoidance of possible complications associated with moving the patient to the radiotherapy department in the immediate postoperative period.

Chronic Extradural Haemorrhage

A case of chronic extradural haemorrhage with a presumed time interval of 5-6 weeks between injury and diagnosis at postmortem examination is presented. The literature relating to this entity has been reviewed, and relevant features commented upon, including time intervals, age, sex, location, clinical features, pathological findings, associated skull fractures, mechanisms involved, and the source of the bleeding.

Associations between cyclosporine therapy and interstitial fibrosis in renal allograft biopsies.

A retrospective masked study of 120 consecutive renal transplant biopsies was performed to evaluate the potential associations of cyclosporine (CsA) therapy and other factors on the degree and progression of interstitial fibrosis (IF). Allograft biopsies were obtained from patients receiving CsA (CsA+; n = 59) and not receiving CsA (CsA-; n = 46); pretransplant donor biopsies were used as controls (n = 15). IF was evaluated by histologic grading (0-3+) as well as by quantitative morphometric measurements of Masson's trichrome stain positive material. Other biopsy measurements included the pattern of IF (focal, diffuse; graded 0-3+), and tubular epithelial cell reactivity, necrosis, and vacuolization (each graded 0-3+). Potential confounding variables were also considered, including time interval between transplant and biopsy; creatinine levels at the time of biopsy, 2 weeks and 10 weeks postbiopsy, and the last stable (baseline) creatinine prior to biopsy; recipient age, clinical evidence of rejection, and duration of rejection reactions; transplant number; and postbiopsy graft outcome. No significant difference in any measure of IF was found between all CsA+ vs. CsA- patients, although both groups showed a highly significant increase in IF compared with control pretransplant donor biopsies. Similarly, no differences in tubular changes or the patterns of fibrosis were identified between CsA groups. However, since the mean interval between transplant and biopsy was significantly (P less than 0.04) greater for the CsA- group, measures of creatinine and IF were normalized by the time interval between transplant and biopsy, and were stratified into biopsies obtained before or after 6 months posttransplant. By this stratification and normalization, both the baseline creatinine (P less than 0.01) and the degree of IF as measured by morphometry (P less than 0.04) were significantly higher in the CsA+ group, but only for biopsies obtained greater than 6 months posttransplant. Evaluation of biopsies less than 6 months posttransplant normalized by interval showed no suggested differences between the CsA+ and CsA- groups in terms of creatinine levels or any measure of IF. Tubular epithelial changes were not different in the CsA+ and CsA- groups within either period. These results suggest that CsA therapy is not associated with increased interstitial fibrosis in renal allografts prior to 6 months posttransplant, after which there is a significant increase in fibrosis relative to patients not receiving CsA.