Clinical study of neutrophil-to-lymphocyte ratio and platelet-tolymphocyte ratio in hypertriglyceridemia-induced acute pancreatitis and acute biliary pancreatitis with persistent organ failure

BACKGROUND The neutrophil-to-lymphocyte ratio(NLR)and platelet-to-lymphocyte ratio(PLR)are novel inflammatory indicators that can be used to predict the severity and prognosis of various diseases.We categorize acute pancreatitis by etiology into acute biliary pancreatitis(ABP)and hypertriglyceridemia-induced acute pancreatitis(HTGP).AIM To investigate the clinical significance of NLR and PLR in assessing persistent organ failure(POF)in HTGP and ABP.METHODS A total of 1450 patients diagnosed with acute pancreatitis(AP)for the first time at Shanxi Bethune Hospital between January 2012 and January 2023 were enrolled.The patients were categorized into two groups according to the etiology of AP:ABP in 530 patients and HTGP in 241 patients.We collected and compared the clinical data of the patients,including NLR,PLR,and AP prognostic scoring systems,within 48 h of hospital admission.RESULTS The NLR(9.1 vs 6.9,P<0.001)and PLR(203.1 vs 160.5,P<0.001)were significantly higher in the ABP group than in the HTGP group.In the HTGP group,both NLR and PLR were significantly increased in patients with severe AP and those with a SOFA score≥3.Likewise,in the ABP group,NLR and PLR were significantly elevated in patients with severe AP,modified computed tomography severity index score≥4,Japanese Severity Score≥3,and modified Marshall score≥2.Moreover,NLR and PLR showed predictive value for the development of POF in both the ABP and HTGP groups.CONCLUSION NLR and PLR vary between ABP and HTGP,are strongly associated with AP prognostic scoring systems,and have predictive potential for the occurrence of POF in both ABP and HTGP.

THE PERSISTENCE OF SOLUTIONS IN A NONLOCAL PREDATOR-PREY SYSTEM WITH A SHIFTING HABITAT

In this paper,we mainly study the propagation properties of a nonlocal dispersal predator-prey system in a shifting environment.It is known that Choi et al.[J Differ Equ,2021,302:807-853]studied the persistence or extinction of the prey and of the predator separately in various moving frames.In particular,they achieved a complete picture in the local diffusion case.However,the question of the persistence of the prey and of the predator in some intermediate moving frames in the nonlocal diffusion case was left open in Choi et al.'s paper.By using some a prior estimates,the Arzelà-Ascoli theorem and a diagonal extraction process,we can extend and improve the main results of Choi et al.to achieve a complete picture in the nonlocal diffusion case.

Risk factors associated with intraoperative persistent hypotension in pancreaticoduodenectomy

BACKGROUND Intraoperative persistent hypotension(IPH)during pancreaticoduodenectomy(PD)is linked to adverse postoperative outcomes,yet its risk factors remain unclear.AIM To clarify the risk factors associated with IPH during PD,ensuring patient safety in the perioperative period.METHODS A retrospective analysis of patient records from January 2018 to December 2022 at the First Affiliated Hospital of Nanjing Medical University identified factors associated with IPH in PD.These factors included age,gender,body mass index,American Society of Anesthesiologists classification,comorbidities,medication history,operation duration,fluid balance,blood loss,urine output,and blood gas parameters.IPH was defined as sustained mean arterial pressure<65 mmHg,requiring prolonged deoxyepinephrine infusion for>30 min despite additional deoxyepinephrine and fluid treatments.RESULTS Among 1596 PD patients,661(41.42%)experienced IPH.Multivariate logistic regression identified key risk factors:increased age[odds ratio(OR):1.20 per decade,95%confidence interval(CI):1.08-1.33](P<0.001),longer surgery duration(OR:1.15 per additional hour,95%CI:1.05-1.26)(P<0.01),and greater blood loss(OR:1.18 per 250-mL increment,95%CI:1.06-1.32)(P<0.01).A novel finding was the association of arterial blood Ca^(2+)<1.05 mmol/L with IPH(OR:2.03,95%CI:1.65-2.50)(P<0.001).CONCLUSION IPH during PD is independently associated with older age,prolonged surgery,increased blood loss,and lower plasma Ca^(2+).

Beyond Defense: Proactive Approaches to Disaster Recovery and Threat Intelligence in Modern Enterprises

As cyber threats keep changing and business environments adapt, a comprehensive approach to disaster recovery involves more than just defensive measures. This research delves deep into the strategies required to respond to threats and anticipate and mitigate them proactively. Beginning with understanding the critical need for a layered defense and the intricacies of the attacker’s journey, the research offers insights into specialized defense techniques, emphasizing the importance of timely and strategic responses during incidents. Risk management is brought to the forefront, underscoring businesses’ need to adopt mature risk assessment practices and understand the potential risk impact areas. Additionally, the value of threat intelligence is explored, shedding light on the importance of active engagement within sharing communities and the vigilant observation of adversary motivations. “Beyond Defense: Proactive Approaches to Disaster Recovery and Threat Intelligence in Modern Enterprises” is a comprehensive guide for organizations aiming to fortify their cybersecurity posture, marrying best practices in proactive and reactive measures in the ever-challenging digital realm.

Development and Validation of a Postoperative Prognostic Nomogram to Predict Recurrence in Patients with Persistent Atrial Fibrillation:A Retrospective Cohort Study

Background:Patients with persistent atrial fibrillation(PsAF)have a high risk of recurrence after catheter radiofre-quency ablation.Nevertheless,no effective prognostic tools have been developed to identify these high-risk patients to date.This study sought to develop and validate a simple linear predictive model for predicting postoperative recurrence in patients with PsAF.Methods:From June 2013 to June 2021,patients with PsAF admitted to our hospital were enrolled in this single-center,retrospective,observational study.The characteristics substantially associated with recurrence in patients with PsAF were screened through univariate and multivariate logistic regression analysis.The receiver operating charac-teristic curve was used to assess the predictive significance of the nomogram model after nomogram development.Furthermore,to assess the clinical value of the nomogram,we performed calibration curve and decision curve analyses.Results:A total of 209 patients were included in the study,42(20.10%)of whom were monitored up to 1 year for recurrent AF.The duration of AF episodes,left atrial diameter,BMI,CKMB,and alcohol consumption were found to be independent risk factors(P<0.05)and were integrated into the nomogram model development.The area under the curve was 0.895,the sensitivity was 93.3%,and the specificity was 71.4%,thus indicating the model’s excellent predic-tive ability.The C-index of the predictive nomogram model was 0.906.Calibration curve and decision curve analyses further revealed that the model had robust prediction and strong discrimination ability.Conclusion:This simple,practical,and innovative nomogram can help clinicians in evaluation of the risk of PsAF recurrence after catheter ablation,thus facilitating preoperative evaluation,postoperative monitoring and ultimately the construction of more personalized therapeutic protocols.

Acute and Persistent Post-Craniotomy Pain: A Prospective 6-Month Follow-Up Questionnaire Study

Introduction: The incidence of acute pain after craniotomy differs remarkably in previous studies, and the prevalence of persistent pain is not precisely known. We conducted 6-month follow-up surveys on the incidence and intensity of acute and persistent pain after elective craniotomy. Methods: We carried out a prospective cohort study via a series of structured questionnaires to record acute pain intensity preoperatively and postoperatively, and the incidence of persistent pain 3 and 6 months after a craniotomy in a tertiary care center. Patients scheduled for elective craniotomy were interviewed the day before surgery, postoperatively before discharge from the hospital, and 3 and 6 months after surgery. Pain was assessed on a numeric rating scale (0 - 10) at rest and movement, as well as expectations of pain before surgery, efficacy of pain therapy, and satisfaction with pain treatment. The incidence of adverse events, sleep time and interruptions caused by pain, different pain types, and drugs used for pain treatment were also recorded. Results: A total of 152 patients were enrolled in the study and completed the preoperative questionnaire;123 (81%) completed postoperative questionnaire and 108 (72%) completed the 3- and 6-month follow-ups. The average pain score at the time of the postoperative questionnaire was moderate, 4 at rest and 5 upon movement. The percentage of patients experiencing mild pain at rest and upon movement was 52% and 49%, and moderate pain was 15% and 16%, respectively. Severe postoperative pain was detected in 5% and 8% of patients at rest and upon movement, respectively. Three months after surgery, 6% of patients reported mild pain at rest, 3% moderate pain at rest, and 1% severe pain at rest. Persistent mild and moderate pain at rest after 6 months was reported by 3% and 1% of patients, respectively. The most common adverse events were postoperative nausea and vomiting (11%) and abdominal discomfort (8%). During postoperative pain treatment in the intensive care unit or post-anesthesia care unit, 92% of patients received acetaminophen, 88% fentanyl, and 24% oxycodone. During neurosurgical ward care, ibuprofen was used in 61% of patients. Satisfaction with analgesia was high throughout the study period with a median satisfaction score of 9 postoperatively and 10 at 3 and 6 months on the 0 - 10 scale. Conclusion: The findings indicate that most patients experience moderate or mild pain after craniotomy, but patient satisfaction with pain treatment is high. Persistent pain after 3 and 6 months is rare and mild in nature.

Clinicopathological and oncological significance of persistent prostate-specific antigen after radical prostatectomy:A systematic review and meta-analysis

Objective:To investigate the association of persistently elevated prostate-specific antigen(PSA)after radical prostatectomy(RP)with clinicopathological features and long-term oncological prognosis for the development of a potential management strategy.Methods:A systematic literature search was performed using PubMed and Web of Science up to June 2021 to identify the eligible studies focusing on understanding the impact of persistent PSA in patients who underwent RP for localized prostate cancer.Meta-analyses were performed on parameters with available information.Results:A total of 32 RP studies were identified,of which 11 included 26719 patients with consecutive cohorts and the remaining 21 comprised 24177 patients with cohorts carrying specific restrictions.Of the 11 studies with consecutive cohorts,the incidence of persistent PSA varied between 3.1%and 34.6%with a median of 11.0%.Meta-analyses revealed patients with persistent PSA consistently showed unfavorable clinicopathological features and a more than 3.5-fold risk of poorer biochemical recurrence,metastasis,and prostate cancer-specific mortality prognosis independently,when compared to patients with undetectable PSA.Similarly,cases with persistent PSA in different specific patient cohorts with a higher risk of prostate cancer also showed a trend of worse outcomes.Conclusion:We found that the frequency of persistent PSA was about 11.0%in consecutive RP cohorts.Persistent PSA was significantly associated with unfavorable clinicopathological characteristics and worse oncological outcomes.Patients with persistent PSA after RP may benefit from early salvage treatment to delay or prevent biochemical recurrence,improving oncological outcomes for these patients.Further prospective randomized controlled trials are warranted to understand optimal systemic therapy in these patients.

Effects of non-liquefiable crust layer and superstructure mass on the response of 2×2 pile groups to liquefaction-induced lateral spreading

In this research,two shake table experiments were conducted to study the effects of non-liquefiable crust layer and superstructure mass on the responses of two sets of 22 pile groups to liquefactioninduced lateral spreading.In this regard,an inclined base layer overlain by a very loose liquefiable layer was constructed in both models;while only in one model,a non-liquefiable crust layer was built.A lumped mass,being representative of a superstructure,was attached to the cap of one pile group in both models.The models were fully instrumented with various sensors,including acceleration,displacement,and pore water pressure transducers.Also,the piles were instrumented with pair strain gauges to measure pure bending moments induced by cyclic and monotonic loadings associated with ground shaking and lateral spreading,respectively.The results showed that the existence of the non-liquefiable crust layer increases both the maximum and residual soil displacements at the free field and also the maximum bending moments in the piles.The results of the experiments indicated that the crust layer induces a high kinematic lateral soil pressure and force on the piles which are not present in the crustless case.The crust layer increases the pile cap displacement before liquefaction,albeit decreases it after liquefaction,due to the elastic rebound of the piles in the liquefiable layer.The crust layer postpones both liquefaction triggering and dissipation of excess pore water pressure.The existence of the superstructure mass on the pile caps decreases the acceleration amplitude of the pile caps,while increases their maximum displacement.

Integrated analysis of comorbidity, pregnant outcomes, and amniotic fluid cytogenetics of fetuses with persistent left superior vena cava

BACKGROUND Persistent left superior vena cava(PLSVC)is the most common venous system variant.The clinical characteristics and amniotic fluid cytogenetics of fetuses with PLSVC remain to be further explored.AIM To develop reliable prenatal diagnostic recommendations through integrated analysis of the clinical characteristics of fetuses with PLSVC.METHODS Cases of PLSVC diagnosed using prenatal ultrasonography between September 2019 and November 2022 were retrospectively studied.The clinical characteristics of the pregnant women,ultrasonic imaging information,gestational age at diagnosis,pregnancy outcomes,and amniocentesis results were summarized and analyzed using categorical statistics and the chi-square test or Fisher’s exact test.RESULTS Of the 97 cases diagnosed by prenatal ultrasound,49(50.5%)had isolated PLSVC and 48(49.5%)had other structural abnormalities.The differences in pregnancy outcomes and amniocentesis conditions between the two groups were statistically significant(P<0.05).No significant differences were identified between the two groups in terms of advanced maternal age and gestational age(P>0.05).According to the results of the classification statistics,the most common intrac-ardiac abnormality was a ventricular septal defect and the most common extrac-ardiac abnormality was a single umbilical artery.In the subgroup analysis,the concurrent combination of intra-and extracardiac structural abnormalities was a risk factor for adverse pregnancy outcomes(odds ratio>1,P<0.05).Additional-ly,all abnormal cytogenetic findings on amniocentesis were observed in the comorbidity group.One case was diagnosed with 21-trisomy and six cases was diagnosed with chromosome segment duplication.CONCLUSION Examination for other structural abnormalities is strongly recommended when PLSVC is diagnosed.Poorer pregnancy outcomes and increased amniocentesis were observed in PLSVC cases with other structural abnor-malities.Amniotic fluid cytogenetics of fetuses is recommended for PLSVC with other structural abnormalities.

Individual dynamics and local heterogeneity provide a microscopic view of the epidemic spreading

The COVID-19 pandemic has caused severe global disasters,highlighting the importance of understanding the details and trends of epidemic transmission in order to introduce efficient intervention measures.While the widely used deterministic compartmental models have qualitatively presented continuous “analytical” insight and captured some transmission features,their treatment usually lacks spatiotemporal variation.Here,we propose a stochastic individual dynamical(SID)model to mimic the random and heterogeneous nature of epidemic propagation.The SID model provides a unifying framework for representing the spatiotemporal variations of epidemic development by tracking the movements of each individual.Using this model,we reproduce the infection curves for COVID-19 cases in different areas globally and find the local dynamics and heterogeneity at the individual level that affect the disease outbreak.The macroscopic trend of virus spreading is clearly illustrated from the microscopic perspective,enabling a quantitative assessment of different interventions.Seemingly,this model is also applicable to studying stochastic processes at the “meter scale”,e.g.,human society’s collective dynamics.

The burden of upper motor neuron involvement is correlated with the bilateral limb involvement interval in patients with amyotrophic lateral sclerosis:a retrospective observational study

Amyotrophic lateral sclerosis is a rare neurodegenerative disease characterized by the involvement of both upper and lower motor neurons.Early bilateral limb involvement significantly affects patients'daily lives and may lead them to be confined to bed.However,the effect of upper and lower motor neuron impairment and other risk factors on bilateral limb involvement is unclear.To address this issue,we retrospectively collected data from 586 amyotrophic lateral sclerosis patients with limb onset diagnosed at Peking University Third Hospital between January 2020 and May 2022.A univariate analysis revealed no significant differences in the time intervals of spread in different directions between individuals with upper motor neuron-dominant amyotrophic lateral sclerosis and those with classic amyotrophic lateral sclerosis.We used causal directed acyclic graphs for risk factor determination and Cox proportional hazards models to investigate the association between the duration of bilateral limb involvement and clinical baseline characteristics in amyotrophic lateral sclerosis patients.Multiple factor analyses revealed that higher upper motor neuron scores(hazard ratio[HR]=1.05,95%confidence interval[CI]=1.01–1.09,P=0.018),onset in the left limb(HR=0.72,95%CI=0.58–0.89,P=0.002),and a horizontal pattern of progression(HR=0.46,95%CI=0.37–0.58,P<0.001)were risk factors for a shorter interval until bilateral limb involvement.The results demonstrated that a greater degree of upper motor neuron involvement might cause contralateral limb involvement to progress more quickly in limb-onset amyotrophic lateral sclerosis patients.These findings may improve the management of amyotrophic lateral sclerosis patients with limb onset and the prediction of patient prognosis.

Characteristics and Mechanisms of Persistent Wet–Cold Events with Different Cold-air Paths in South China

We investigate the characteristics and mechanisms of persistent wet–cold events(PWCEs)with different types of coldair paths.Results show that the cumulative single-station frequency of the PWCEs in the western part of South China is higher than that in the eastern part.The pattern of single-station frequency of the PWCEs are“Yangtze River(YR)uniform”and“east–west inverse”.The YR uniform pattern is the dominant mode,so we focus on this pattern.The cold-air paths for PWCEs of the YR uniform pattern are divided into three types—namely,the west,northwest and north types—among which the west type accounts for the largest proportion.The differences in atmospheric circulation of the PWCEs under the three types of paths are obvious.The thermal inversion layer in the lower troposphere is favorable for precipitation during the PWCEs.The positive water vapor budget for the three types of PWCEs mainly appears at the southern boundary.

Insider threat detection approach for tobacco industry based on heterogeneous graph embedding

In the tobacco industry,insider employee attack is a thorny problem that is difficult to detect.To solve this issue,this paper proposes an insider threat detection method based on heterogeneous graph embedding.First,the interrelationships between logs are fully considered,and log entries are converted into heterogeneous graphs based on these relationships.Second,the heterogeneous graph embedding is adopted and each log entry is represented as a low-dimensional feature vector.Then,normal logs and malicious logs are classified into different clusters by clustering algorithm to identify malicious logs.Finally,the effectiveness and superiority of the method is verified through experiments on the CERT dataset.The experimental results show that this method has better performance compared to some baseline methods.

The Transport and Persistence of Escherichia coli in Leachate from Poultry Litter Amended Soils

Fecal coliform bacteria such as Escherichia coli (E. coli) are one of the main sources of groundwater pollution. An assessment of the transport and Persistence of E. coli in poultry litter amended Decatur silty Clay soil and Hartsells Sandy soil was conducted using soil columns and simulated groundwater leaching. Enumeration of initial E. coli was determined to range from 2.851 × 103 to 3.044 × 103 CFU per gram of soil. These results have been used in a batch study to determine the persistence rate of E. coli in Decatur silty Clay soil and Hartsells Sandy soil. Results prove that E. coli survival growth rate increases for clay soil later than and at a higher rate than sandy soil. The column study has determined that E. coli was transported at a rate of 3.7 × 106 CFU for Decatur silty loam and 6.3 × 106 CFU for Hartsells sandy per gram of soil. Further, linear regression analysis predictions show higher porosity and soil moisture content affect transport, and Hartsells sandy soil has higher transport of E. coli due to its higher porosity and lower volumetric water content.

Topological phase transition in network spreading

This paper investigates information spreading from the perspective of topological phase transition.Firstly,a new hybrid network is constructed based on the small-world networks and scale-free networks.Secondly,the attention mechanism of online users in information spreading is studied from four aspects:social distance,individual influence,content richness,and individual activity,and a dynamic evolution model of connecting with spreading is designed.Eventually,numerical simulations are conducted in three types of networks to verify the validity of the proposed dynamic evolution model.The simulation results show that topological structure and node influence in different networks have undergone phase transition,which is consistent with the phenomenon that followers and individual influence in real social networks experience phase transition within a short period.The infection density of networks with the dynamic evolution rule changes faster and reaches higher values than that of networks without the dynamic evolution rule.Furthermore,the simulation results are compared with the real data,which shows that the infection density curve of the hybrid networks is closer to that of the real data than that of the small-world networks and scale-free networks,verifying the validity of the model proposed in this paper.

Optimization of communication topology for persistent formation in case of communication faults

To address the optimization problem of communication topology for persistent formation in the case of communication faults such as link interruption,transmitter failure,and receiver failure a two-stage model including fast reconstruction of communication topology and re-optimization of communication topology is constructed.Then,a fast reconstruction algorithm of communication topology for persistent formation(FRA-CT-PF),based on optimally rigid graph,arc addition operation,and path reversal operation,is proposed,which can quickly generate a feasible reconstructed communication topology after communication faults,thus ensuring the safety of the agents and maintaining the formation shape of persistent formation.Furthermore,a re-optimization algorithm of communication topology for persistent formation(ROA-CTPF),based on agent position exchange,is proposed,which can further obtain a reoptimized communication topology to minimize the formation communication cost while still maintaining the formation shape of persistent formation.The time complexities of these two algorithms are also analyzed.Finally,the effectiveness of the above algorithms is verified by numerical experiments.Compared with existing algorithms,FRA-CT-PF can always obtain feasible reconstructed communication topology in much less time under all communication fault scenarios,and ROA-CT-PF can obtain a reoptimized communication topology to further reduce the formation communication cost in a shorter time.

A New Model for Spreading Malware over SMS Using Network Automata

By the year 2026, it is estimated that the number of smartphone users in Mexico will be approximately 118.1 million. Each smartphone has the functionality of sending and receiving SMS (Short Message Service) messages, which pose a significant threat to all users, as it makes any device vulnerable to a malware attack. In particular, worm-type malware takes advantage of this means of communication in order to spread. Studying the dynamics of malware propagation can help understand and prevent massive contagion between mobile devices. In this work, a model based on Network Automata and compartmental epidemiological models is presented, aiming to simulate, analyze and study the spread of worm-like malware through sending SMS on smartphones.

Update on the current management of persistent and recurrent primary hyperparathyroidism after parathyroidectomy

Primary hyperparathyroidism(pHPT)is the third most common endocrine disease.The surgical procedure aims for permanent cure,but recurrence has been reported in 4%-10%of pHPT patients.Preoperative localization imaging is highly valuable.It includes ultrasound,computed tomography(CT),single-photonemission CT,sestamibi scintigraphy and magnetic resonance imaging.The operation has been defined as successful when postoperative continuous eucalcemia exists for more than the first six months.Ongoing hypercalcemia during this period is defined as persistence,and recurrence is defined as hypercalcemia after six months of normocalcemia.Vitamin D is a crucial factor for a good outcome.Intraoperative parathyroid hormone(PTH)monitoring can safely predict the outcomes and should be suggested.PTH≤40 pg/mL or the traditional decrease≥50%from baseline minimizes the likelihood of persistence.Risk factors for persistence are hyperplasia and normal parathyroid tissue on histopathology.Risk factors for recurrence are cardiac history,obesity,endoscopic approach and low-volume center(at least 31 cases/year).Cases with double adenomas or four-gland hyperplasia have a greater likelihood of persistence/recurrence.A 6-mo calcium>9.7 mg/dL and eucalcemic parathyroid hormone elevation at 6 mo may be associated with recurrence necessitating long-term follow-up.18F-fluorocholine positron emission tomography and 4-dimensional CT in persistent and recurrent cases can be valuable before reoperation.With these novel advances in preoperative imaging and localization as well as intraoperative PTH measurement,the recurrence rate has dropped to 2.5%-5%.Sixmonth serum calcium≥9.8 mg/dL and parathyroid hormone≥80 pg/mL indicate a risk of recurrence.Negative sestamibi scintigraphy,diabetes and elevated osteocalcin levels are predictors of multiglandular disease,which brings an increased risk of persistence and recurrence.Bilateral neck exploration was considered the gold-standard diagnostic method.Minimally invasive parathyroidectomy and neck exploration are both effective surgical techniques.Multidisciplinary diagnostic and surgical management is required to prevent persistence and recurrence.Long-term follow-up,even up to 10 years,is necessary.

Persistent left superior vena cava in right hemiarch replacement under deep hypothermic circulatory arrest:A case report

BACKGROUND Persistent left superior vena cava(PLSVC),a relatively rare thoracic vascular malformation,can inconvenience perfusionists and operators when encountered during deep hypothermic circulatory arrest(DHCA).CASE SUMMARY Herein,we describe the case of a patient with concurrent giant aortic arch aneurysm,aortic stenosis,and PLSVC.To treat these conditions,we performed right hemiarch and aortic valve replacements under DHCA.Notably,we applied“bilateral superior vena cava retrograde cerebral perfusion(RCP)”for cerebral protection,which significantly optimized the surgical procedure and reduced the risk of postoperative complications.The patient was discharged 14 d after surgery with no complications.CONCLUSION Surgical intervention for PLSVC under DHCA can be performed using the bilateral superior vena cava RCP approach.

Impact of random and scattered coincidences from outside of field of view on positron emission tomography/computed tomography imaging with different reconstruction protocols

Image quality in positron emission tomography(PET)is affected by random and scattered coincidences and reconstruction protocols.In this study,we investigated the effects of scattered and random coincidences from outside the field of view(FOV)on PET image quality for different reconstruction protocols.Imaging was performed on the Discovery 690 PET/CT scanner,using experimental configurations including the NEMA phantom(a body phantom,with six spheres of different sizes)with a signal background ratio of 4:1.The NEMA phantom(phantom I)was scanned separately in a one-bed position.To simulate the effect of random and scatter coincidences from outside the FOV,six cylindrical phantoms with various diameters were added to the NEMA phantom(phantom II).The 18 emission datasets with mean intervals of 15 min were acquired(3 min/scan).The emission data were reconstructed using different techniques.The image quality parameters were evaluated by both phantoms.Variations in the signal-to-noise ratio(SNR)in a 28-mm(10-mm)sphere of phantom II were 37.9%(86.5%)for ordered-subset expectation maximization(OSEM-only),36.8%(81.5%)for point spread function(PSF),32.7%(80.7%)for time of flight(TOF),and 31.5%(77.8%)for OSEM+PSF+TOF,respectively,indicating that OSEM+PSF+TOF reconstruction had the lowest noise levels and lowest coefficient of variation(COV)values.Random and scatter coincidences from outside the FOV induced lower SNR,lower contrast,and higher COV values,indicating image deterioration and significantly impacting smaller sphere sizes.Amongst reconstruction protocols,OSEM+PSF+TOF and OSEM+PSF showed higher contrast values for sphere sizes of 22,28,and 37 mm and higher contrast recovery coefficient values for smaller sphere sizes of 10 and 13 mm.