CER Group Research Articles

The influence of contextual uncertainty on facial expression processing: Evidence from behavior and ERPs

The brain helps individuals build expectations based on emotional prediction, facilitating the processing of faces in social interactions. Due to the intricacy of the environment, accurately predicting emotions remains a formidable task. Contextual uncertainty represents a state characterized by the inability to predict when, how, and why events occur. It leads to intensified sentiments and triggers adverse emotions like anxiety. Therefore, comprehending the influences of contextual uncertainty carries importance. The present study utilized event-related potentials (ERPs) technology to investigate contextual uncertainty's influence on facial expression processing. We employed a novel S1-S2 paradigm, using scene images as S1 and faces as S2. From the learning phase into the testing phase, the certain to uncertain group (CER to UNC) experienced more unpredictability (increased uncertainty), whereas the uncertain to certain group (UNC to CER) experienced more predictability (decreased uncertainty). This allowed for manipulating dynamic alterations in predictive relationships. The behavioral results showed that the valence ratings of neutral facial expressions were more negative in the CER to UNC group with increased contextual uncertainty. The ERP results showed that the more negative SPN (stimulus preceding negativity) amplitudes and positive LPP (late positive potential) amplitudes were observed in the UNC to CER group with decreased contextual uncertainty, compared to the CER to UNC group with increased contextual uncertainty. These findings have indicated that contextual uncertainty affects facial expression processing. In summary, these results contributed to comprehending the contextual uncertainty.

Long-term visual outcomes and fluid compartment changes in limited-early versus early response to anti-VEGF treatment for diabetic macular edema

ObjectiveThis study assessed best visual acuity (BVA) and central subfield thickness (CST) outcomes for LER (limited early responder) and ER (early responder) patients at 24 and 36 months. DesignRetrospective chart review ParticipantsOne-hundred and twelve patients characterized at 3 months after their first anti-VEGF injections as either LER if they met the anatomic criteria (aLER = CST reductions ≤ 10%), visual criteria (vLER = ETDRS letter gains < 5 letter), or both (cLER). All other patients were classified as ER (aER/vER/cER). MethodsVariables collected include CST and ETDRS letters at baseline, 3, 24, and 36 months following injections, comorbidities, smoking status, demographics, baseline systemic factors, and the type and quantity of anti-VEGF injections. Analyses were performed using Welch's t-test, multivariable linear and multivariable logistic regression. ResultsBVA changes from 3 months were significant between cLER versus cER and vLER versus vER groups (p < 0.05). There was a greater decrease in mean BVA from 3 months to 36 months in the cER group compared to the cLER group. Alternatively, mean BVA decreased in the vER cohort, while the vLER cohort slightly increased. CST changes from 3 months were statistically significant (p < 0.01) between all LER and ER groups with LER groups showing greater reductions compared to ER counterparts. BVA and CST changes from baseline to 24 and 36 months were not significant after controlling for baseline differences between LER and ER groups. ConclusionResults highlight the value of long-term anti-VEGF treatment and the need to further explore options that may lead to continued BVA improvements beyond 3 months.

Patient-reported outcomes during accelerating the en-masse retraction of the upper anterior teeth using low-intensity electrical stimulation: a randomized controlled trial

BackgroundLow-intensity electrical stimulation (LIES) is considered a relatively recent technology that has received little attention in orthodontics as a method of acceleration. This study aimed to evaluate patient-reported outcome measures when LIES is used to accelerate the en-masse retraction of the upper anterior teeth.Materials and methodsThe sample consisted of 40 patients (8 males, 32 females; mean age 21.1 ± 2.3 years), with Class II division I malocclusion who required extraction of the first premolars to retract upper anterior teeth. They were randomly assigned to the LIES group (n = 20) and the conventional en-masse retraction group (CER; n = 20). Patient responses regarding pain, discomfort, burning sensation, swelling, chewing difficulty, speech difficulty, and painkillers’ consumption were recorded at these nine assessment times: 24 h (T1), 3 days (T2), and 7 days (T3) after force application, then in the second month after 24 h (T4), 3 days (T5), and 7 days (T6) of force re-activation, and finally after 24 h (T7), 3 days (T8), and 7 days (T9) of force re-activation in the third month.ResultsThe mean values of pain perception were smaller in the LIES group than those in the CER group at all assessment times with no statistically significant differences between the two groups except during the second and third months (T5, T6, T8, and T9; P < 0.005). However, discomfort mean values were greater in the LIES group with significant differences compared to CER group during the first week of the follow-up only (T1, T2, and T3; P < 0.005). Burning sensation levels were very mild in the LIES group, with significant differences between the two groups at T1 and T2 only (P < 0.001). Speech difficulty was significantly greater in the LIES group compared to CER group at all studied times (P < 0.001). High levels of satisfaction and acceptance were reported in both groups, without any significant difference.ConclusionBoth the LIES-based acceleration of en-masse retraction of upper anterior teeth and the conventional retraction were accompanied by mild to moderate pain, discomfort, and chewing difficulty on the first day of retraction. These sensations gradually decreased and almost disappeared over a week after force application or re-activation.Trial registrationClinicalTrials.gov, ClinicalTrials.gov, NCT05920525. Registered 17 June 2023 - retrospectively registered, http://clinicaltrials.gov/study/NCT05920525?term=NCT05920525&rank=1.

Residual Short-Segment Distal Inflammation Has No Significant Impact on the Major Relapse of Extensive Ulcerative Colitis.

Mucosal healing is a treatment target for patients with ulcerative colitis. However, the relevance of proactive treatment for residual inflammation limited to the distal colon is unclear. Patients with ulcerative colitis who had extensive colitis in clinical remission and underwent colonoscopy were retrospectively enrolled and followed up for 2 years. Patients with complete endoscopic remission (CER; Mayo endoscopic subscore [MES] of 0) and those with short-segment distal inflammation (SS; active inflammation only in the sigmoid colon and/or rectum with a proximal MES of 0) were compared for the incidence of minor (only symptomatic) and major (need for induction treatments or hospitalization) relapses. A total of 91 patients with CER and 54 patients with SS were identified and 63 relapses (47 minor and 16 major) were analyzed. Univariate analysis showed that minor relapses were significantly more frequent in the SS group than in the CER group (hazard ratio [HR], 2.22; 95% confidence interval [CI], 1.25-3.97), but major relapses were not more frequent in the SS group than in the CER group (HR, 1.78; 95% CI, 0.65-4.83). Multivariable analysis showed that SS was the only risk factor significantly associated with minor relapse (HR, 2.38; 95% CI, 1.31-4.36). When the SS group was stratified by MES of 1 vs 2/3, minor relapses were significantly more frequent in the subgroup with MES of 2/3 than in the CER group, whereas the incidence of major relapse remained similar. Residual short-segment distal inflammation is not a risk factor for major relapses as long as endoscopic remission is achieved in the proximal colon. Therefore, reactive but not proactive treatment may be appropriate for such lesions.

Revealing the Disturbed Vaginal Micobiota Caused by Cervical Cancer Using High-Throughput Sequencing Technology.

Cervical cancer is the fourth most prevalent cancer type among all malignancies, so it is of great significance to find its actual pathogenesis mechanisms. In the present study, 90 women were enrolled, and high-throughput sequencing technology was firstly used to analyze the vaginal microbiota of healthy women (C group), cervical intraepithelial neoplasia patients (CIN group) and cervical cancer patients (CER group). Our results indicates that compared with C group, a higher HPV infection rate as well as increased Neutrophil ratio and tumor marker squamous cell carcinoma antigen (SCCA) were obtained, and a decrease in Lymphocyte ratio and Hemoglobin were also present. In addition, the cervical cancer showed a strong association with reduced probiotics Lactobacillus, increased pathogens Prevotella spp., Sneathia spp. and Pseudomonas spp. These results prove that the immunological changes generated by the cervical cancer and the vaginal microbiota can interact with each other. However, further study investigating the key bacteria for cervical cancer is still needed, which can be a clue for the diagnosis or treatment of cervical cancer.

Effects of Two Types of Calorie Restriction on Methylation Levels of Adiponectin Receptor 1 (AdipoR1) and Leptin Receptor Overlapping Transcript (Leprot) in a MMTV-TGF-α Breast Cancer Mouse Model.

The role of adiponectin and leptin signalling pathways has been suggested to play important roles in the protective effects of energy restriction (ER) on mammary tumour (MT) development. To study the effects of ER on the methylation levels in adiponectin receptor 1 (AdipoR1) and leptin receptor overlapping transcript (Leprot) genes using the pyrosequencing method in mammary fat pad tissue, mouse mammary tumour virus-transforming growth factor-α (MMTV-TGF-α) female mice were randomly assigned to ad libitum (AL), chronic ER (CER, 15 % ER) or intermittent ER (3 weeks AL and 1 week 60 % ER in cyclic periods) groups at 10 weeks of age until 82 weeks of age. The methylation levels of AdipoR1 in the CER group were higher than those in the AL group at week 49/50 (P < 0·05), while the levels of methylation for AdipoR1 and Leprot genes were similar among the other groups. Also, the methylation levels at CpG2 and CpG3 regions of the promoter region of the AdipoR1 gene in the CER group were three times higher (P < 0·05), while CpG1 island of Leprot methylation was significantly lower compared with the other groups (P < 0·05). Adiponectin and leptin gene expression levels were consistent with the methylation levels. We also observed a change with ageing in methylation levels of these genes. These results indicate that different types of ER modify methylation levels of AdipoR1 and Leprot in different ways and CER had a more significant effect on methylation levels of both genes. Epigenetic regulation of these genes may play important roles in the preventive effects of ER against MT development and ageing processes.

Effects of two types of energy restriction on methylation levels of adiponectin receptor 1 and leptin receptor overlapping transcript in a mouse mammary tumour virus-transforming growth factor-α breast cancer mouse model.

The role of adiponectin and leptin signalling pathways has been suggested to play important roles in the protective effects of energy restriction (ER) on mammary tumour (MT) development. To study the effects of ER on the methylation levels in adiponectin receptor 1 (AdipoR1) and leptin receptor overlapping transcript (Leprot) genes using the pyrosequencing method in mammary fat pad tissue, mouse mammary tumour virus-transforming growth factor-α (MMTV-TGF-α) female mice were randomly assigned to ad libitum (AL), chronic ER (CER, 15 % ER) or intermittent ER (3weeks AL and 1 week 60 % ER in cyclic periods) groups at 10weeks of age until 82weeks of age. The methylation levels of AdipoR1 in the CER group were higher than those in the AL group at week 49/50 (P < 0·05), while the levels of methylation for AdipoR1 and Leprot genes were similar among the other groups. Also, the methylation levels at CpG2 and CpG3 regions of the promoter region of the AdipoR1 gene in the CER group were three times higher (P < 0·05), while CpG1 island of Leprot methylation was significantly lower compared with the other groups (P < 0·05). Adiponectin and leptin gene expression levels were consistent with the methylation levels. We also observed a change with ageing in methylation levels of these genes. These results indicate that different types of ER modify methylation levels of AdipoR1 and Leprot in different ways and CER had a more significant effect on methylation levels of both genes. Epigenetic regulation of these genes may play important roles in the preventive effects of ER against MT development and ageing processes.

The Effectiveness of Open Educational Resources in College Calculus. A Quantitative Study

We investigate Open Educational Resources (OER) in post-secondary Calculus with face-to-face instruction using web-based homework in a side-by-side comparison with Closed (Proprietary) Educational Resources (CER). Statistical analyses using multilinear regression models are developed to demonstrate several significant effects, to within a probability of 5%. Our first finding is that students’ pretest scores and access dates to online homework were both significant factors in predicting first exam scores. While pretest scores were similar between the groups, students in the OER group accessed the online homework earlier in the semester, which contributed to higher first exam scores. Second, homework scores were significantly higher in the CER group, which was a significant measure of final exam scores. In understanding this result, we cite student comments suggesting the proprietary CER homework system had more resources providing help on problems. However, the differences in final course grades were not significant. We conclude from our study that the OER materials are effective, but recommend that care is taken to ensure the free materials provide a quality experience.

Research of fatty acid synthase complex inhibitors cer on growth inhibition in human bladder cancer nude mice transplanted tumor

Objective To investigate the application of cerulenin (cer) inhibiting fatty acid synthase complex (FASN) on human bladder cancer nude mice transplanted tumor growth. Methods Human bladder cancer nude mice transplanted tumor models were established, and 20 nude mice were randomly divided into 2 groups: the control group and the cer group. Observe and record the change of weight and the volume of the transplanted tumor. The expression of proliferation cell nuclear antigen (Ki-67) was determined by immunocytochemistry (IC). Apoptosis levels of transplanted tumor were detected by TdT-mediated dUTP nick end labeling (TUNEL) assays. Results Random grouping of the nude mice respectively the Cer and Dimethylsulfoxide (DMSO) weight change has no significantly difference after the treatment. Tumour volumes in the experimental group were significantly smaller than those in the control group (P=0.023), the expression of Ki-67 were significantly lower than those in the control group (P=0.034), the apoptotic indexes were significantly higher than the control group (P=0.026). Conclusion FASN inhibitors Cer can promote nude mice transplantation tumor cell apoptosis and has significantly inhibitory effect on transplanted tumor growth. Key words: Fatty acid synthase complex; Cer; Bladder cancer; Proliferation cell nuclear antigen; Apoptosis; Nude mice

Better surgical outcome by image-guided navigation system in endoscopic removal of sinonasal inverted papilloma

PurposeThe purpose of this study was to validate and compare treatment outcomes for endoscopic resection of sinonasal inverted papilloma (IP) with or without the use of a navigation system. Materials and methodsA total of 58 patients who underwent endoscopic resection of sinonasal inverted papilloma by a single surgeon from 2007 to 2016 at our institution were retrospectively reviewed. Depending on the use of the navigation system, subjects were divided into two groups: a conventional endoscopic resection group without navigation system (CER group) and a navigation-assisted endoscopic resection group (NER group). ResultsThere were 24 patients (41.4%) in the CER group and 34 patients (58.6%) in the NER group. Treatment outcomes showed that navigation-assisted endoscopic resection was a more beneficial surgical technique than conventional endoscopic resection for sinonasal IP. Post-surgical recurrence was noted in seven cases (29.2%) in the CER group and two cases (5.9%) in the NER group. Accordingly, the recurrence rate was significantly less in the NER group compared to the CER group (p = 0.026). There were two cases of complications (8.3%) in the CER group comprising cerebrospinal fluid leak and periorbital fat exposure, while no complications were noted for the NER group (p = 0.167). ConclusionThis study demonstrated that navigation-assisted endoscopic removal of sinonasal IP is helpful for reducing recurrence and avoiding surgical complications. Therefore, navigation systems should be always considered when performing endoscopic removal of sinonasal IP.

Assessment of complementary feeding of Canadian infants: effects on microbiome & oxidative stress, a randomized controlled trial

BackgroundThe World Health Organization recommends exclusive breastfeeding until 6 months followed by introduction of iron-rich complementary foods (CFs). The aim of this study was to determine the impact of different iron-rich CFs on infant gut inflammation and microbiota.MethodsEighty-seven exclusively breastfed infants were randomly assigned to receive one of the following as their first CF: iron-fortified cereal (Cer), iron-fortified cereal with fruit (Cer + Fr), or meat (M). Urine and stool samples were collected to assess reactive oxygen species (ROS) generation, gut microbiota and inflammation.ResultsFecal iron differed across feeding groups (p < 0.001); levels were highest in the Cer group and lowest in M group. A significant increase of fecal ROS formation (p < 0.002) after the introduction of CFs was observed, but did not differ across feeding groups. Fecal calprotectin increased within all groups after the introduction of CFs (p = 0.004). Gut microbiota richness increased after introduction of M or Cer + Fr. Regardless of feeding group, Coriobacteriaceae were positively correlated with ROS and Staphylococcaceae were negatively correlated with calprotectin.ConclusionsChoice of first CF may influence gut inflammation and microbiota, potentially due to variations in iron absorption from different foods. Further research is warranted to fully characterize these associations and to establish implications for infant health. This study was registered in the ClinicalTrial.gov registry (Identifier No. NCT01790542).Trial registrationThis study was registered in the ClinicalTrial.gov registry under the name “Assessment of Complementary Feeding of Canadian Infants” (Identifier No. NCT01790542) February 6, 2013.

A pilot clinical study of immediate provisionalization with a chairside computer aided design and computer aided manufacture monolithic crown for single tooth immediate implant placement

Objective: To evaluate the primary clinical outcomes of immediate provisionalization with a monolithic crown utilizing a novel chairside computer aided design and computer aided manufacture (CAD/CAM) workflow for single tooth immediate implant placement. Methods: This pilot study was a prospective within-subjects design. Thirteen consecutive patients were included and diagnosed with untreatable single incisor or premolar with fine general and local anatomical conditions. The trial was conducted at Department of Implantology, Peking University School and Hospital of Stomatology, Beijing, between January 2016 and June 2016. The teeth were extracted atraumatically and implants were immediately placed in the fresh sockets. Two screw-retained interim crowns were fabricated for the same site utilizing different workflows, a monolithic lithium disilicate (LS2) crown produced by CEREC (Sirona, Germany) chairside CAD/CAM system (CER group) and a manually fabricated resin crown utilizing conventional workflow (CONV group) respectively. The patients were blinded to the group allocation of the two interim crowns. After the clinical try-in for both crowns in a randomized sequence, the patients' level of satisfaction was assessed with a virtual analogue scale (VAS) questionnaire. The restorations chosen by patients themselves were seated in the implants by one experienced prosthodontist. The accuracy, aesthetic effect and clinical time consumption of both groups were compared. Statistical analyses were performed with the Wilcoxon signed rank test. Results: All patients were treated with atraumatic tooth extraction, immediate implant placement using flapless surgery and immediate provisionalization in a single visit. The interim crowns of both groups could be fitted with or without slight adjustments. For each patient, the interim crown of CER group was chosen to be seated with a relatively higher VAS result. The white esthetic score (WES) results demonstrated no statistically significant difference between CER group (7.5±1.1) and CONV group (7.9±0.9) (P>0.05). The mean total work time was significantly different resulting in (131.9±5.0) min for CER group and (205.2±6.3) min(P<0.05). The major difference lied in the laboratory work time, resulting in (113.5±6.3) min for CER group which was significantly shorter than (185.6±6.6) min for CONV group. As for impression taking time, the CER group (7.5±0.8) min was significantly shorter than CONV group (11.7± 1.1) min (P<0.05). However, analysis for clinical adjustment time showed a significantly longer time for CER group [(11.0±2.1) min vs (8.0±2.8) min, P<0.05]. After 3-6 months of observation, the overall survival rate was 100%. Screw loosening occurred in 4 patients and was tightened again. No other major complication soccurred. Conclusions: The full digital workflow utilizing CEREC chairside CAD/CAM system to fabricate interim crowns after immediate implant placement in one single visit was feasible. It was more time-efficient and could effectively shorten the laboratory work time compared to the conventional workflow. Patients demonstrated high satisfaction and there was no statistical difference in WES results compared to the conventional workflow. Favorable clinical outcomes were gained in this short-term follow-up study.

Diversity of Cervicovaginal Microbiota Associated with Female Lower Genital Tract Infections

The female genital tract (FGT) harbors very large numbers of bacterial species that are known to play an important role on vaginal health. Previous studies have focused on bacterial diversity in the vagina, but little is known about the ectocervical microbiota associated with FGT infections. In our study, vaginal swabs and ectocervical swabs were collected from 100 participants in China, including 30 women with bacterial vaginosis (BV; BV group), 22 women with cervicitis (Cer group), 18 women with BV in combination with cervicitis (BC group) and 30 healthy control women (CN group). The diversity and richness of cervicovaginal microbiota were investigated with culture-independent polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR) targeting 11 microorganisms that have been associated with FGT infections. Despite significant interpersonal variations, the PCR-DGGE profiles revealed that vaginal microbiota and ectocervical microbiota were clearly much more complex in the BV group, while the ectocervical microbiota showed no significant difference between healthy and diseased participants. Using species-specific qPCR, BV and cervicitis were significantly associated with a dramatic decrease in Lactobacillus species (p < 0.05), and potential pathogenic species such as Gardnerella, Atopobium, Eggerthella, Leptotrichia/Sneathia, and Prevotella were more common and in higher copy numbers in BV than in CN samples (p values ranged from 0.000 to 0.021). No significant differences were observed between healthy and cervicitis samples (p > 0.05) in ectocervical microbiota. The total numbers of bacteria were significantly lower in the ectocervix as compared in the vagina (p < 0.05). Intriguingly, vaginal microbiota from participants with BV in combination with cervicitis was quite different from that of participants with BV or cervicitis alone. Our study demonstrated that the cervicovaginal microbiota was actively involved in the process of FGT infections. The predominant bacteria of the cervicovaginal communities were clearly associated with BV; however, there was not sufficient evidence that the ectocervical microbiota is directly involved in the development of cervicitis.

Comparison of cobalt chromium, ceramic and pyrocarbon hemiprostheses in a rabbit model: Ceramic leads to more cartilage damage than cobalt chromium

Cartilage wear after hemiarthroplasty remains a problem in orthopedic surgery. The main cause of cartilage wear, apart from incongruency of the joint partners, is generally considered to be the tribology of the material surfaces. This study evaluates in 27 rabbits the degree of cartilage wear of the tibia plateau after hemiarthroplasty with proximal interphalangeal prostheses made of three different materials [cobalt chromium (CoCr), pyrocarbon (PyCa), and ceramic (Cer)]. Three months after hemiarthroplasty, the articulating tibial cartilage was histomorphologically examined and degenerative damage was graded using the modified Mankin score. The mechanical capacity of the cartilage was assessed by stress relaxation testing. The biomechanical properties of the cartilage were significantly superior in the CoCr group as compared with the Cer group (p < 0.03), indicating less damage to the articulating cartilage surface. The Mankin score showed significantly lower values in the CoCr compared with Cer group (p = 0.011), whereas no differences were found between PyCa and CoCr or PyCa and Cer. In contrast to earlier reports, in this hemiarthroplasty model, the CoCr alloy showed less cartilage damage than a ceramic surface. Further, in vivo experiments are necessary to elucidate the controversial issue of the most suitable material for hemiarthroplasty.

Antioxidant systemic effect of short-term Cerebrolysin administration.

Levels of catalase (CAT) and superoxide dismutase (SOD) activity were determinate in serum of intact rats (INT) and those with septohippocampal pathway lesion (SHPL), which received Cerebrolysin (CRB) or saline solution (SAL) for a week. We found that Cerebrolysin induces a decrease on the CAT and SOD levels. Decrease of CAT levels (19.1) in the group of SHPL-CRB was higher than the values obtained (57.3) in SHPL-SAL group. The lowest CAT levels were detected in the INT-CER group (16.7). The SOD levels obtained in SHPL-CER group (9.84) were also smaller than those obtained in the SHPL-SAL group (14.9) which showed the highest levels of SOD, while the INT animals showed the lowest levels (7.6). In addition, the SHPL animals mortality was of 18% for the CER group against 43% for SAL group. We suggest the Cerebrolysin effect on CAT and SOD activity is related with a beneficial antioxidative role which may have potential application on brain injury.

FIELD EVALUATION OF GROWTH AND NITROGEN FIXATION IN PEAS SELECTED FOR HIGH AND LOW PHOTOSYNTHETIC CO2 EXCHANGE

Six genotypes of pea (Pisum sativum L.), selected for either high or low CO2 exchange rate per unit leaf area (CER) on the basis of field measurements, were grown in field plots during 1978 and 1979. During two growing seasons, CER was determined in leaves of different physiological age at several times of the day and season. Dry weights, leaf areas and node numbers were determined 4, 7 and 10 wk after planting, and again after pod ripening. C2H2 reduction by detached roots was measured 5, 6, 8 and 9 wk after planting. Despite the large variability in CER with years, leaf numbers, and times of measurement, the mean CER of the three genotypes selected for high rates was always greater than that of the low selected group. CER was significantly correlated with growth per unit leaf area (E) and the high to low group ratios averaged 1.4 for CER and 1.3 for E. C2H2 reduction on an equivalent leaf area basis was not different in the two groups. On a land area basis, the low CER group had a significantly greater leaf area index which compensated for the decreased CER, and estimates of total CO2 exchange, growth and C2H2 reduction were similar in the two groups. Total aboveground dry matter and seed yields were greater in the low CER group, but harvest index was generally greater in those genotypes selected for high CER.

Task difficulty and conditioned suppression in humans

Conditioned emotional responses were produced by pairing a tone CS with 15 slides portraying surgical procedures. Presentation of the CS during color naming on a Stroop test resulted in significantly slower performance in a CER group than in a control group, but it had no effect on groups performing a word-reading Stroop task. It was concluded that some past failures to obtain conditioned suppression in humans might be due to the nature of the tasks used.