The burden of metabolic dysfunction-associated steatotic liver disease and viral hepatitis in Saudi Arabia.

BACKGROUND: Globally, viral hepatitis is decreasing, but nonalcoholic fatty liver disease (NAFLD), now metabolic dysfunction-associated steatotic liver disease (MASLD), is increasing. We assessed the burden and trends of MASLD and viral hepatitis in Saudi Arabia. METHODS: Prevalence, death, and disability data due to MASLD, hepatitis C virus (HCV), and hepatitis B virus (HBV) were obtained from 2019 Global Burden of Disease (GBD) database for Saudi Arabia. Time trends were assessed by annual percent change (APC) from joinpoint regression. RESULTS: From 2012 through 2019, MASLD prevalence in children and adults increased from 28.02% (n = 8.34 million) to 33.11% (n = 11.83 million); APC +2.43% (95% confidence interval: 2.33% to 2.54%). HBV prevalence decreased from 1.83% (n = 0.54 million) to 1.53% (n = 0.55 million); APC -1.74% (-2.66% to -0.81%). HCV prevalence stabilized from 0.72% (n = 0.21 million) to 0.73% (n = 0.26 million): APC +0.32% (-0.13% to 0.78%). Among adults (>20 years), MASLD prevalence increased from 40.64% to 43.95% (APC = +1.15%, 1.12% to 1.18%), HBV prevalence decreased from 2.67% to 2.05% (APC = -2.96%, -3.90% to -2.01%), and HCV leveled from 0.88% to 0.86% (APC = -0.30%, -0.75% to 0.16%). MASLD liver mortality rate from liver cancer and cirrhosis increased: APC of +1.15% (0.82% to 1.48%) from 1.31 to 1.43 (per 100,000). HBV and HCV liver mortality increased at slower rates (APC = +0.78%, 0.38% to 1.19%): 2.07 to 2.20 (per 100,000) and (APC = +0.55%, 0.09% to 0.89%): 6.32 to 6.61 (per 100,000), respectively. CONCLUSIONS: MASLD burden is increasing, while HBV and HCV burden is decreasing/remaining stable. Early prevention and diagnosis health policies for MASLD are needed.

The Production Effect Becomes Spatial.

In the verbal domain, it is well established that words read aloud are better remembered than their silently read counterparts. It has been hypothesized that this production effect stems from the addition of distinctive features, with the caveat that the processing that generates added features interferes with rehearsal. Here, we tested the idea that a similar trade-off is found in the visuospatial domain. In all experiments, a short series of single dots sequentially appeared at various locations on a screen. Participants produced the items by clicking on them at presentation, watched the items appear quietly, or produced an irrelevant click after each item to better even out rehearsal opportunities between produced and control conditions. In Experiment 1, the dots appeared within a visible grid and an order reconstruction task was used. Experiment 2 also called upon reconstruction, but with the grid removed. In Experiments 3, a recall task was used. The results show that producing items hindered performance compared to the control condition. Conversely, production improved performance compared to the control condition where rehearsal was hindered. This is the first demonstration of a visuospatial production effect. The key findings were successfully modeled by the Revised Feature Model (RFM).

Informatics-Based Learning of Oxygen Vacancy Ordering Principles in Oxygen-Deficient Perovskites.

Ordered oxygen vacancies (OOVs) in perovskites can exhibit long-range order and may be used to direct materials properties through modifications in electronic structures and broken symmetries. Based on the various vacancy patterns observed in previously known compounds, we explore the ordering principles of oxygen-deficient perovskite oxides with ABO2.5 stoichiometry to identify other OOV variants. We performed first-principles calculations to assess the OOV stability on a data set of 50 OOV structures generated from our bespoke algorithm. The algorithm employs uniform planar vacancy patterns on (111) pseudocubic perovskite layers and the approach proves effective for generating stable OOV patterns with minimal computational loads. We find as expected that the major factors determining the stability of OOV structures include coordination preferences of transition metals and elastic penalties resulting from the assemblies of polyhedra. Cooperative rotational modes of polyhedra within the OOV structures reduce elastic instabilities by optimizing the bond valence of A- and B cations. This finding explains the observed formation of vacancy channels along low-index crystallographic directions in prototypical OOV phases. The identified ordering principles enable us to devise other stable vacancy patterns with longer periodicity for targeted property design in yet to be synthesized compounds.

Statistical primer: Composite endpoints and competing risks analysis.

Composite end-points are common primary outcomes in clinical trials. Their main benefit of utilizing a composite outcome is increasing the number of primary outcome events meaning fewer participants are required to deliver an adequately powered trial. By combining multiple important end-points in the primary outcome rather than having to select only one, composite end-points potentially make clinically meaningful benefits easier to detect and avoid ranking outcomes hierarchically. However there are a number of important considerations when designing and interpreting clinical trials that utilize composite end-points. In this Statistical Primer, issues with composite end-points such as competing events, halo effect, risk of bias, time to event limitations and the win ratio are discussed in the context of real world clinical trials.

Epidemiologic Assessment of Craniosynostosis in Mississippi's Pediatric Population from 2015 to 2020.

OBJECTIVES: This study aimed to report geographic and demographic patterns of patients with craniosynostosis (CS) treated at Children's of Mississippi, the state's only American Cleft Palate-Craniofacial Association-approved craniofacial team. METHODS: Patients with CS were treated at a tertiary pediatric hospital cared for by craniofacial surgeons and neurosurgeons from 2015 to 2020. Demographic, geographic, and CS diagnosis details, including sex, gestational age, race, ethnicity, insurance status, and affected cranial suture type(s), number, and associated syndromic diagnosis were collected, including birth county and total live births from state data. Significant differences between prevalence of CS in four regions of Mississippi were examined using two-tailed t tests (P < 0.05). RESULTS: Among 222,819 live births in Mississippi between 2015 and 2020, 79 pediatric patients presented to Children's of Mississippi with CS, with an overall incidence of 0.355/1000 live births. Most cases were nonsyndromic CS (82%, n = 65) affecting a single major cranial suture (81%, n = 64). The overall incidence of CS was higher in the coastal and central regions compared with northeast Mississippi, at 0.333 and 0.527 vs 0.132/1000 live births (P = 0.012 and P = 0.004), respectively. CONCLUSIONS: Results from this study suggest regional patterns of CS in Mississippi, which may reflect actual incidence patterns or proximity to Children's of Mississippi. Further study could reveal regional differences in risk factors underlying CS incidence or access to specialized CS care for different regions in the state. This will lead to opportunities for institutional outreach to decrease the burden of CS care in Mississippi.

Chemoinformatics Insights on Molecular Jackhammers and Cancer Cells.

One of the most challenging tasks in modern medicine is to find novel efficient cancer therapeutic methods with minimal side effects. The recent discovery of several classes of organic molecules known as "molecular jackhammers" is a promising development in this direction. It is known that these molecules can directly target and eliminate cancer cells with no impact on healthy tissues. However, the underlying microscopic picture remains poorly understood. We present a study that utilizes theoretical analysis together with experimental measurements to clarify the microscopic aspects of jackhammers' anticancer activities. Our physical-chemical approach combines statistical analysis with chemoinformatics methods to design and optimize molecular jackhammers. By correlating specific physical-chemical properties of these molecules with their abilities to kill cancer cells, several important structural features are identified and discussed. Although our theoretical analysis enhances understanding of the molecular interactions of jackhammers, it also highlights the need for further research to comprehensively elucidate their mechanisms and to develop a robust physical-chemical framework for the rational design of targeted anticancer drugs.

Risk Factors of Pelvic Floor Disorders Among Women in Rural Nepal: A Case-Control Study.

INTRODUCTION AND HYPOTHESIS: Risk factors for pelvic floor disorders (PFDs) are not well understood in lower resource settings. The objective of this study is to determine the risk factors associated with stress urinary incontinence (SUI), urge urinary incontinence (UUI), and pelvic organ prolapse (POP) among women of reproductive age in rural Nepal. METHODS: This is a case-control study nested within a community-based cross-sectional survey of parous women of reproductive age with PFDs in the Sarlahi District of Nepal. The presence of PFDs was confirmed by clinical assessment. Detailed sociodemographic information and histories were captured. RESULTS: We examined 406 women; the mean (SD, range) age was 32.7 (8.5, 16-49) years, mean BMI (SD) was 19.7 (3.3) kg/m2, and median (range) number of pregnancies was 4 (1-11). Two hundred and three women (50.0%) had either SUI or UUI, 85 (17.8%) had both SUI and UUI, and 71 (17.5%) had POP at or beyond the hymen. After controlling for other variables significant on bivariate analysis, age (adjusted odds ratio [aOR] 1.06 [95% CI 1.03-1.09]), illiteracy (aOR 2.24 [95% CI 1.04-4.80]), and presence of upper gastrointestinal issues (aOR 3.30, [95% CI 1.77-6.16]) were independently associated with SUI/UUI. Age (aOR 1.05 [95% CI 1.02-1.09]), bispinous diameter (aOR 2.88 ([95% CI 1.11-7.47]), and subpubic angle (aOR 2.78 [95% CI 1.55-5.03]) were independently associated with POP. CONCLUSION: Risk factors for PFDs in a homogenous community of parous women of reproductive age in rural Nepal are similar to those found in parous women in higher income countries.

Cervicothoracic ventral-dorsal rhizotomy for treatment of brachial hypertonia in cerebral palsy.

PURPOSE: Cervicothoracic ventral-dorsal rhizotomy (VDR) is a potential treatment of medically refractory hypertonia in patients who are not candidates for intrathecal baclofen, particularly in cases of severe upper limb hypertonia with limited to no function. A longitudinal cohort was identified to highlight our institutional safety and efficacy using cervicothoracic VDR for the treatment of hypertonia. METHODS: Retrospective data analysis was performed for patients that underwent non-selective cervicothoracic VDR between 2022 and 2023. Non-modifiable risk factors, clinical variables, and operative characteristics were collected. RESULTS: Six patients (three female) were included. Four patients underwent a bilateral C6-T1 VDR, one patient underwent a left C7-T1 VDR, and another underwent a left C6-T1 VDR. Three patients had quadriplegic mixed hypertonia, one patient had quadriplegic spasticity, one patient had triplegic mixed hypertonia, and one patient had mixed hemiplegic hypertonia. The mean difference of proximal upper extremity modified Ashworth scale (mAS) was - 1.4 ± 0.55 (p = 0.002), and - 2.2 ± 0.45 (p < 0.001) for the distal upper extremity. Both patients with independence noted quality of life improvements as well as increased ease with dressing and orthotics fits. Caregivers for the remaining four patients noted improvements in caregiving provision, mainly in dressing, orthotics fit, and ease when transferring. CONCLUSION: Cervicothoracic VDR is safe and provides tone control and quality of life improvements in short-term follow-up. It can be considered for the treatment of refractory hypertonia. Larger multicenter studies with longer follow-up are necessary to further determine safety along with long-term functional benefits in these patients.

Effect of Hepatic Impairment on Trofinetide Exposures Using an In Silico Physiologically Based Pharmacokinetic Model.

INTRODUCTION: Trofinetide is the first drug to be approved for the treatment of Rett syndrome. Hepatic impairment is not expected to affect the pharmacokinetic (PK) profile of trofinetide because of predominant renal excretion. This study was conducted to help understand the potential impact of any hepatic impairment on trofinetide PK. METHODS: This study used physiologically based PK modeling to estimate trofinetide exposure (maximum drug concentration and area under the concentration-time curve from time zero to infinity) in virtual patients with mild, moderate, and severe hepatic impairment (per Child-Pugh classification) compared with virtual healthy subjects following a 12 g oral trofinetide dose. RESULTS: In individual deterministic simulations for matched individuals and stochastic simulations at the population level (100 virtual individuals simulated per population), as anticipated, predicted plasma exposures were similar for healthy subjects and for patients with mild, moderate, and severe hepatic impairment. However, predicted blood concentration exposures slightly increased with increasing severity of hepatic impairment because of change in hematocrit levels. CONCLUSION: This study indicates that hepatic impairment is not expected to have a clinically relevant effect on exposure to trofinetide.

Trofinetide is the first approved treatment for Rett syndrome, a rare genetic condition that affects brain development. When a person takes trofinetide, most is removed from the body via the urine in its unchanged form (no chemical alteration). Regulatory requirements mean researchers must confirm the safety of any pharmaceutical drug and evaluate whether changes in liver function lead to harmful levels of drug exposure. Researchers used a computer model to predict how much trofinetide would be present in the blood and plasma (the liquid portion of blood) over time in virtual healthy subjects and virtual patients with varying degrees of liver disease (mild, moderate, or severe). Computer simulations showed that predicted trofinetide levels in plasma were similar in virtual healthy subjects and each virtual patient group with liver disease. Predicted levels of trofinetide in blood were slightly elevated with increasing severity of liver disease. This is because people with liver disease have fewer red blood cells, so the cell portion of blood becomes smaller relative to the liquid portion (plasma), which leads to higher trofinetide concentrations in whole blood (trofinetide minimally enters the red blood cell). The small increase in trofinetide levels in blood and the absence of any change in trofinetide levels in plasma means that people with Rett syndrome and liver disease are unlikely to be exposed to harmful levels of trofinetide after a 12 g oral dose.

Variation in the fitted filtration efficiency of disposable face masks by sex.

BACKGROUND & OBJECTIVE: Disposable face masks are a primary protective measure against the adverse health effects of exposure to infectious and toxic aerosols such as airborne viruses and particulate air pollutants. While the fit of high efficiency respirators is regulated in occupational settings, relatively little is known about the fitted filtration efficiencies of ear loop style face masks worn by the public. METHODS: We measured the variation in fitted filtration efficiency (FFE) of four commonly worn disposable face masks, in a cohort of healthy adult participants (N = 100, 50% female, 50% male, average age = 32.3 ± 9.2 years, average BMI = 25.5 ± 3.4) using the U.S. Occupational Safety and Health Administration Quantitative Fit Test, for an N95 (respirator), KN95, surgical, and KF94 masks. The latter three ear loop style masks were additionally tested in a clip-modified condition, tightened using a plastic clip to centrally fasten loops in the back of the head. RESULTS: The findings show that sex is a major determinant of the FFE of KN95, surgical, and KF94 masks. On average, males had an 11% higher FFE relative to females, at baseline testing. We show that a simple modification using an ear loop clip, results in improvements in the average FFE for females but provides comparatively minor changes for males. On average, females had a 20% increased FFE when a clip was worn behind the head, relative to a 6% increase for males. IMPACT: The efficacy of a disposable face mask as protection against air contaminants depends on the efficiency of the mask materials and how well it fits the wearer. We report that the sex of the wearer is a major determinant of the baseline fitted filtration efficiency (FFE) of commonly available ear loop style face masks. In addition, we show that a simple fit modifier, an ear loop clip fastened behind the head, substantially improves baseline FFE for females but produces only minor changes for males. These findings have significant public health implications for the use of face masks as a protective intervention against inhalational exposure to airborne contaminants.

The first casualty of COVID-19 for patients nearing death was human dignity: Understanding the experience of palliative care patients during the COVID-19 pandemic.

The COVID-19 pandemic changed the way people lived, but also the way they died. It accentuated the physical, psychological, social, and spiritual vulnerabilities of patients approaching death. This study explored the lived experience of palliative inpatients during the pandemic. We conducted interviews with 22 palliative inpatients registered in a Canadian urban palliative care program, aimed to uncover how the pandemic impacted participants' experiences of approaching end-of-life. The reflexive thematic analysis revealed 6 themes: putting off going into hospital, the influence of the pandemic on hospital experience, maintaining dignity in care, emotional impact of nearing death, making sense of end-of-life circumstances and coping with end-of-life. Findings highlight the vulnerability of patients approaching death, and how that was accentuated during the pandemic. Findings reveal how the pandemic strained, threatened, and undermined human connectedness. These lived experiences of palliative inpatients offer guidance for future pandemic planning and strategies for providing optimal palliative care.

Late Recurrence of Completely Resected Stage I-IIIA Lung Adenocarcinoma.

OBJECTIVE: Research into the risk factors associated with late recurrence (>2 years after surgery) of lung adenocarcinoma (LUAD) is limited. We investigated the incidence of and clinicopathologic and genomic features associated with late recurrence of resected stage I-IIIA LUAD. METHODS: We performed a retrospective analysis of patients with completely resected pathologic stage I-IIIA LUAD (2010-2019). Patients with a history of lung cancer, neoadjuvant therapy, or mucinous or noninvasive LUAD, or with follow-up of <2 years were excluded. Cox and logistic regression modeling were used to compare clinicopathologic variables among patients with no, early (≤2 years), and late recurrence. Comparisons of genomic mutations were corrected for multiple testing. RESULTS: Of the 2349 patients included, 537 developed a recurrence during follow-up. Most recurrences (55% [297/537]) occurred early; 45% (240/537) occurred late. A larger proportion of late recurrences than early recurrences were locoregional (37% vs. 29%; p=0.047). Patients with late recurrence had more aggressive pathologic features (IASLC grade 2 and 3, lymphovascular invasion, visceral pleural invasion) and higher stage than patients without recurrence. Pathologic features were similar between patients with early and late recurrence, except stage IIIA disease was more common in the early cohort. No genomic mutations were associated with late recurrence. CONCLUSIONS: Late recurrence of LUAD following resection is more common than previously reported. Patients without disease >2 years after surgery who had aggressive pathologic features at the time of resection have an elevated risk of recurrence and may benefit from more-aggressive follow-up.

The subcutaneous adipose transcriptome identifies a molecular signature of insulin resistance shared with visceral adipose.

OBJECTIVE: The objective of this study was to identify the transcriptional landscape of insulin resistance (IR) in subcutaneous adipose tissue (SAT) in humans across the spectrum of obesity. METHODS: We used SAT RNA sequencing in 220 individuals with metabolic phenotyping. RESULTS: We identified a 35-gene signature with high predictive accuracy for homeostatic model of IR that was expressed across a variety of non-immune cell populations. We observed primarily "protective" IR associations for adipocyte transcripts and "deleterious" associations for macrophage transcripts, as well as a high concordance between SAT and visceral adipose tissue (VAT). Multiple SAT genes exhibited dynamic expression 5 years after weight loss surgery and with insulin stimulation. Using available expression quantitative trait loci in SAT and/or VAT, we demonstrated similar genetic effect sizes of SAT and VAT on type 2 diabetes and BMI. CONCLUSIONS: SAT is conventionally viewed as a metabolic buffer for lipid deposition during positive energy balance, whereas VAT is viewed as a dominant contributor to and prime mediator of IR and cardiometabolic disease risk. Our results implicate a dynamic transcriptional architecture of IR that resides in both immune and non-immune populations in SAT and is shared with VAT, nuancing the current VAT-centric concept of IR in humans.

A case-cohort study of per- and polyfluoroalkyl substance concentrations and incident prostate cancer in the Cancer Prevention Study-II LifeLink Cohort study.

INTRODUCTION: Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent, potentially carcinogenic chemicals. Previous studies investigating PFAS exposure and prostate cancer yielded mixed findings. We aimed to investigate associations between PFAS exposure and incident prostate cancer in a large cohort of U.S. men, overall and by selected demographic, lifestyle, and medical-related characteristics. METHODS: We conducted a case-cohort study among Cancer Prevention Study-II LifeLink Cohort participants who, at baseline (1998-2001), had serum specimens collected and no prior cancer diagnosis. The study included all men diagnosed with prostate cancer (n=1610) during follow-up (baseline-June 30, 2015) and a random sub-cohort of 500 men. PFAS concentrations [perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), and perfluorooctanoic acid (PFOA)] were measured in stored serum specimens. We used multivariable Cox proportional hazards models to estimate associations between PFAS concentrations and prostate cancer, overall and by selected characteristics (grade, stage, family history, age, education, smoking status, and alcohol consumption). RESULTS: Prostate cancer hazards were slightly higher among men with concentrations in the highest (Q4) vs lowest quartile (Q1) for PFHxS [hazard ratio (HR) (95% CI): 1.18 (0.88-1.59)] and PFOS [HR (95% CI): 1.18 (0.89-1.58)], but not for PFNA or PFOA. However, we observed heterogeneous associations by age, family history of prostate cancer (PFHxS), alcohol consumption (PFHxS), and education (PFNA). For example, no meaningful associations were observed among men aged <70 years at serum collection, but among men aged ≥70 years, HRs (95% CIs) comparing Q4 to Q1 were PFHxS 1.54 (1.02-2.31) and PFOS 1.62 (1.08-2.44). No meaningful heterogeneity in associations were observed by tumor grade or stage. CONCLUSIONS: Our findings do not clearly support an association between the PFAS considered and prostate cancer. However, positive associations observed in some subgroups, and consistently positive associations observed for PFHxS warrant further investigation.

Associations between asymmetry and reactive balance control during split-belt walking.

The adaptive control of walking is often studied on a split-belt treadmill, where people gradually reduce their step length asymmetries (SLAs) by modulating foot placement and timing. Although it is proposed that this adaptation may be driven in part by a desire to reduce instability, it is unknown if changes in asymmetry impact people's ability to maintain balance in response to destabilizing perturbations. Here, we used intermittent perturbations to determine if changes in SLA affect reactive balance control as measured by whole-body angular momentum (WBAM) in the sagittal and frontal planes. Sixteen neurotypical older adults (70.0 ± 5.3 years old; 6 males) walked on a treadmill at a 2:1 belt speed ratio with real-time visual feedback of their achieved and target step lengths. We used mixed-effects models to determine if there were associations between SLA or foot placement and WBAM during the applied perturbations. Walking with more positive SLAs was associated with small reductions in forward WBAM (p < 0.001 for fast and slow belts) but increased lateral WBAM (p = 0.045 for fast belt; p = 0.003 for slow belt) during perturbations. When participants walked with more positive SLAs, they shortened their foot placement on the slow belt, and this shortening was associated with moderate reductions in forward WBAM (p < 0.001) and small increases in lateral WBAM (p = 0.008) during slow-belt perturbations. Our findings suggest that spatiotemporal changes that occur during split-belt treadmill walking may improve sagittal-plane stability by reducing people's susceptibility to losses of balance, but this may come at the expense of frontal-plane stability.

Factors affecting implant length in primary inflatable penile prosthesis placement.

OBJECTIVES: To evaluate predictors of implant length for men undergoing primary IPP placement. METHODS: A multicenter, retrospective cohort study was performed for men undergoing primary IPP placement at 16 high-volume surgical centers. Patient demographics, comorbidities, operative approach, and implanted cylinder and rear tip extender length were recorded. Associations between potential preoperative and intraoperative predictors of total device length were tested using non-parametric correlation and Kruskal-Wallis tests, followed by multiple regression. RESULTS: Of 3,951 men undergoing primary IPP placement from July 2016 - July 2021, the median implant length was 20 cm (IQR: 19 - 22). Shorter implant length was associated with increasing age in years (ß = -0.01, p=0.009), Asian ethnicity (ß = -2.34, p=0.008), history of radical prostatectomy (ß = -0.35, p=0.001), and use of an infrapubic surgical approach (ß = -1.02, p<0.001). Black or African American ethnicity was associated with the implantation of longer devices (ß = 0.35, p<0.001). No significant associations were recorded with BMI, history of intracavernosal injections, diabetes mellitus, tobacco use, radiation therapy, Peyronie's disease, priapism, or cavernosal dilation technique. CONCLUSIONS: The length of an implanted penile prosthesis was found to be associated with preoperative and intraoperative factors including history of radical prostatectomy and operative approach. The knowledge of these associations may assist in the preoperative counseling of patients receiving IPP and help create accurate postoperative expectations.

Prenatal Stress Impacts Foetal Neurodevelopment: Temporal Windows of Gestational Vulnerability.

Prenatal maternal stressors ranging in severity from everyday occurrences/hassles to the experience of traumatic events negatively impact neurodevelopment, increasing the risk for the onset of psychopathology in the offspring. Notably, the timing of prenatal stress exposure plays a critical role in determining the nature and severity of subsequent neurodevelopmental outcomes. In this review, we evaluate the empirical evidence regarding temporal windows of heightened vulnerability to prenatal stress with respect to motor, cognitive, language, and behavioural development in both human and animal studies. We also explore potential temporal windows whereby several mechanisms may mediate prenatal stress-induced neurodevelopmental effects, namely, excessive hypothalamic-pituitary-adrenal axis activity, altered serotonin signalling and sympathetic-adrenal-medullary system, changes in placental function, immune system dysregulation, and alterations of the gut microbiota. While broadly defined developmental windows are apparent for specific psychopathological outcomes, inconsistencies arise when more complex cognitive and behavioural outcomes are considered. Novel approaches to track molecular markers reflective of the underlying aetiologies throughout gestation to identify tractable biomolecular signatures corresponding to critical vulnerability periods are urgently required.