Minimal residual disease-driven treatment intensification with sequential addition of ibrutinib to venetoclax in R/R CLL.

Undetectable measurable residual disease (uMRD) is achievable in patients with chronic lymphocytic leukemia (CLL) with the BCL2-inhibitor venetoclax alone or combined with the Bruton's tyrosine kinase inhibitor ibrutinib. This phase 2, multicenter, MRD-driven study was designed to discontinue treatment upon reaching uMRD4 (<10-4) in patients with relapsed/refractory CLL receiving venetoclax monotherapy or after the addition of ibrutinib. Primary end point of the study was proportion of uMRD4 with venetoclax ± ibrutinib. Secondary end points were overall response rate, partial response, complete response, progression-free survival, duration of response, overall survival, and safety of venetoclax ± ibrutinib. Patients with uMRD4 at Cycle 12 Day 1 discontinued venetoclax. MRD+ patients added ibrutinib and continued both drugs up to Cycle 24 Day 28/uMRD4/progression/toxicity. After Cycle 24 Day 28, MRD+ patients continued ibrutinib. Thirty-eight patients (29% with TP53 aberrations; 79% with unmutated IGHV) started venetoclax. Overall response rate with venetoclax was 36 (95%) of 38 patients (20 complete; 16 partial response). Seventeen patients (45%) with uMRD4 at Cycle 12 Day 1 discontinued venetoclax. Nineteen (55%) MRD+ subjects added ibrutinib. After a median of 7 months (range, 3-10 months) of combined treatment, 16 (84%) of 19 achieved uMRD4, thus stopping both drugs. Two MRD+ patients at Cycle 24 Day 28 continued ibrutinib until progression/toxicity. After a median follow-up of 36.5 months, median progression-free survival was not reached; 10 patients progressed (4 restarted venetoclax, 3 without treatment need, 2 developed Richter transformation, and 1 dropped out). Seven (22%) of 32 patients remain uMRD4 after 3 years of follow-up. Neutropenia was the most frequent grade 3 to 4 adverse event; no grade 5 events occurred on study. This sequential MRD-guided approach led to uMRD4 in 33 (87%) of 38 patients, with venetoclax monotherapy or combined with ibrutinib, delivering treatment combination only in a fraction, and ultimately identifying the few patients benefiting from continuous therapy. This trial was registered at www.clinicaltrials.gov as # NCT04754035.

Are we finally getting personal? Moving towards a personalized approach in chronic lymphocytic leukemia.

With its heterogeneous biological features and clinical course, chronic lymphocytic leukemia (CLL), the most frequent adult leukemia in the Western world, is a paradigmatic condition requiring a tailored approach and a precise knowledge of the biology behind each individual patient. This personalized management is becoming even more crucial, since, after decades of preclinical work unravelling the key role of the B-cell receptor (BcR) signalling pathways and the anti-apoptotic mechanisms in CLL cell survival and proliferation, we have now BcR and BCL2 inhibitors available in clinical practice. Thanks to this, we are now able to exploit specific biomarkers to tailor our treatment strategies and improve long-term disease control, patient outcome and quality of life. That notwithstanding, as the disease itself remains incurable, novel challenges and unmet clinical needs have risen from the introduction of novel targeted agents, including mechanisms of resistance at both genetic and epigenetic levels. In this review, we summarize the currently established predictive biomarkers (i.e. IGHV mutation status and TP53 gene disruption) that should be applied in clinical practice to inform treatment decision in 2021 but also discuss the most promising prognostic biomarkers (B-cell receptor stereotypy, complex karyotype, somatic gene mutations, measurable residual disease - MRD) that might become key to define the management of our patients in a near future.

The neonatal DAV-expert algorithm: a GAVeCeLT/GAVePed consensus for the choice of the most appropriate venous access in newborns.

In most NICUs, the choice of the venous access device currently relies upon the operator's experience and preferences. However, considering the high failure rate of vascular devices in the neonatal population, such clinical choice has a critical relevance and should preferably be based on the best available evidence. Though some algorithms have been published over the last 5 years, none of them seems in line with the current scientific evidence. Thus, the GAVePed-which is the pediatric interest group of the most important Italian group on venous access, GAVeCeLT-has developed a national consensus about the choice of the venous access device in the neonatal population. After a systematic review of the available evidence, the panel of the consensus (which included Italian neonatologists specifically experts in this area) has provided structured recommendations answering four sets of questions regarding (1) umbilical venous catheters, (2) peripheral cannulas, (3) epicutaneo-cava catheters, and (4) ultrasound-guided centrally and femorally inserted central catheters. Only statements reaching a complete agreement were included in the final recommendations. All recommendations were also structured as a simple visual algorithm, so as to be easily translated into clinical practice.  Conclusion: The goal of the present consensus is to offer a systematic set of recommendations on the choice of the most appropriate vascular access device in Neonatal Intensive Care Unit.

Ultrasound Guided Catheter Tip Location in Neonates: A Prospective Cohort Study.

OBJECTIVE: To assess point-of-care-ultrasound (POCUS) guided catheter tip location in a neonatal cohort after insertion of percutaneously inserted central catheters (PICCs) from the upper part of the body. STUDY DESIGN: This was a prospective, observational study on PICC tip location. Tip site was assessed by radiological landmarks or direct ultrasound (US) visualization of the cardiovascular structures. RESULTS: One hundred eighteen PICCs (28Gauge/1French) were studied in 102 neonates (mean postmenstrual age 31 weeks, range 25-43 weeks; mean weight at positioning 1365 g, range 420-4180 g). Feasibility of POCUS guided tip location was 92.3% in our population. Failures were significantly associated with mechanical ventilation (aOR 5.33; 95% CI 1.13-29.5; P = .038). Agreement between US and radiographic methods was found in 88 of 109 cases (80.7%). Fifteen of 21 discordant cases led to a change in clinical management. CONCLUSIONS: POCUS guided localization of small bore PICC is a non-invasive and effective alternative to the conventional radiogram. The latter should be recommended when US examination fails to locate the catheter tip.

Epidemiology of Paediatric Italian Food Allergy: Results of the EPIFA study.

Background: Updated epidemiologic data are important for defining effective public health strategies for pediatric food allergy (FA). Objective: The Epidemiology of Paediatric Italian Food Allergy (EPIFA) study was designed to investigate the epidemiology of pediatric FA in one of the most heavily populated Italian regions. Methods: A retrospective cohort study was performed in collaboration with family pediatricians aimed at investigating the epidemiology of Italian pediatric FA during 2009 to 2021. Family pediatricians in the Campania region were invited to use the Google Forms platform for online compilation of data forms. Data forms were reviewed by experienced pediatric allergists at the coordinating center. Results: A total population of 105,151 subjects (aged 0-14 years) was screened during the study period. Data from 752 FA patients were evaluated. A progressive increase in FA incidence and prevalence was observed from 2009 to 2021, with a relative increase up to 34% and 113.6%, respectively, at the end of study period. The relative increase in FA prevalence was higher in the 0-3-year-old age group in the same study period (+120.8%). The most frequent allergens were cow's milk, hen's egg, and nuts. Conclusion: The results of the EPIFA study showed an increase in pediatric FA incidence and prevalence from 2009 to 2021 in Italy. These results underline the necessity of new effective strategies for preventing and managing these conditions.

Reducing mortality in acute kidney injury patients: systematic review and international web-based survey.

OBJECTIVE: To identify all interventions that increase or reduce mortality in patients with acute kidney injury (AKI) and to establish the agreement between stated beliefs and actual practice in this setting. DESIGN AND SETTING: Systematic literature review and international web-based survey. PARTICIPANTS: More than 300 physicians from 62 countries. INTERVENTIONS: Several databases, including MEDLINE/PubMed, were searched with no time limits (updated February 14, 2012) to identify all the drugs/techniques/strategies that fulfilled all the following criteria: (a) published in a peer-reviewed journal, (b) dealing with critically ill adult patients with or at risk for acute kidney injury, and (c) reporting a statistically significant reduction or increase in mortality. MEASUREMENTS AND MAIN RESULTS: Of the 18 identified interventions, 15 reduced mortality and 3 increased mortality. Perioperative hemodynamic optimization, albumin in cirrhotic patients, terlipressin for hepatorenal syndrome type 1, human immunoglobulin, peri-angiography hemofiltration, fenoldopam, plasma exchange in multiple-myeloma-associated AKI, increased intensity of renal replacement therapy (RRT), CVVH in severely burned patients, vasopressin in septic shock, furosemide by continuous infusion, citrate in continuous RRT, N-acetylcysteine, continuous and early RRT might reduce mortality in critically ill patients with or at risk for AKI; positive fluid balance, hydroxyethyl starch and loop diuretics might increase mortality in critically ill patients with or at risk for AKI. Web-based opinion differed from consensus opinion for 30% of interventions and self-reported practice for 3 interventions. CONCLUSION: The authors identified all interventions with at least 1 study suggesting a significant effect on mortality in patients with or at risk of AKI and found that there is discordance between participant stated beliefs and actual practice regarding these topics.

BTK and PLCG2 remain unmutated in one-third of patients with CLL relapsing on ibrutinib.

Patients with chronic lymphocytic leukemia (CLL) progressing on ibrutinib constitute an unmet need. Though Bruton tyrosine kinase (BTK) and PLCG2 mutations are associated with ibrutinib resistance, their frequency and relevance to progression are not fully understood. In this multicenter retrospective observational study, we analyzed 98 patients with CLL on ibrutinib (49 relapsing after an initial response and 49 still responding after ≥1 year of continuous treatment) using a next-generation sequencing (NGS) panel (1% sensitivity) comprising 13 CLL-relevant genes including BTK and PLCG2. BTK hotspot mutations were validated by droplet digital polymerase chain reaction (ddPCR) (0.1% sensitivity). By integrating NGS and ddPCR results, 32 of 49 relapsing cases (65%) carried at least 1 hotspot BTK and/or PLCG2 mutation(s); in 6 of 32, BTK mutations were only detected by ddPCR (variant allele frequency [VAF] 0.1% to 1.2%). BTK/PLCG2 mutations were also identified in 6 of 49 responding patients (12%; 5/6 VAF <10%), of whom 2 progressed later. Among the relapsing patients, the BTK-mutated (BTKmut) group was enriched for EGR2 mutations, whereas BTK-wildtype (BTKwt) cases more frequently displayed BIRC3 and NFKBIE mutations. Using an extended capture-based panel, only BRAF and IKZF3 mutations showed a predominance in relapsing cases, who were enriched for del(8p) (n = 11; 3 BTKwt). Finally, no difference in TP53 mutation burden was observed between BTKmut and BTKwt relapsing cases, and ibrutinib treatment did not favor selection of TP53-aberrant clones. In conclusion, we show that BTK/PLCG2 mutations were absent in a substantial fraction (35%) of a real-world cohort failing ibrutinib, and propose additional mechanisms contributing to resistance.

Thrombotic and bleeding complications in patients with chronic lymphocytic leukemia and severe COVID-19: a study of ERIC, the European Research Initiative on CLL.

BACKGROUND: Patients with chronic lymphocytic leukemia (CLL) may be more susceptible to COVID-19 related poor outcomes, including thrombosis and death, due to the advanced age, the presence of comorbidities, and the disease and treatment-related immune deficiency. The aim of this study was to assess the risk of thrombosis and bleeding in patients with CLL affected by severe COVID-19. METHODS: This is a retrospective multicenter study conducted by ERIC, the European Research Initiative on CLL, including patients from 79 centers across 22 countries. Data collection was conducted between April and May 2021. The COVID-19 diagnosis was confirmed by the real-time polymerase chain reaction (RT-PCR) assay for SARS-CoV-2 on nasal or pharyngeal swabs. Severe cases of COVID-19 were defined by hospitalization and the need of oxygen or admission into ICU. Development and type of thrombotic events, presence and severity of bleeding complications were reported during treatment for COVID-19. Bleeding events were classified using ISTH definition. STROBE recommendations were used in order to enhance reporting. RESULTS: A total of 793 patients from 79 centers were included in the study with 593 being hospitalized (74.8%). Among these, 511 were defined as having severe COVID: 162 were admitted to the ICU while 349 received oxygen supplementation outside the ICU. Most patients (90.5%) were receiving thromboprophylaxis. During COVID-19 treatment, 11.1% developed a thromboembolic event, while 5.0% experienced bleeding. Thrombosis developed in 21.6% of patients who were not receiving thromboprophylaxis, in contrast to 10.6% of patients who were on thromboprophylaxis. Bleeding episodes were more frequent in patients receiving intermediate/therapeutic versus prophylactic doses of low-molecular-weight heparin (LWMH) (8.1% vs. 3.8%, respectively) and in elderly. In multivariate analysis, peak D-dimer level and C-reactive protein to albumin ratio were poor prognostic factors for thrombosis occurrence (OR = 1.022, 95%CI 1.007‒1.038 and OR = 1.025, 95%CI 1.001‒1.051, respectively), while thromboprophylaxis use was protective (OR = 0.199, 95%CI 0.061‒0.645). Age and LMWH intermediate/therapeutic dose administration were prognostic factors in multivariate model for bleeding (OR = 1.062, 95%CI 1.017-1.109 and OR = 2.438, 95%CI 1.023-5.813, respectively). CONCLUSIONS: Patients with CLL affected by severe COVID-19 are at a high risk of thrombosis if thromboprophylaxis is not used, but also at increased risk of bleeding under the LMWH intermediate/therapeutic dose administration.

COVID-19 severity and mortality in patients with CLL: an update of the international ERIC and Campus CLL study.

Patients with chronic lymphocytic leukemia (CLL) may be more susceptible to Coronavirus disease 2019 (COVID-19) due to age, disease, and treatment-related immunosuppression. We aimed to assess risk factors of outcome and elucidate the impact of CLL-directed treatments on the course of COVID-19. We conducted a retrospective, international study, collectively including 941 patients with CLL and confirmed COVID-19. Data from the beginning of the pandemic until March 16, 2021, were collected from 91 centers. The risk factors of case fatality rate (CFR), disease severity, and overall survival (OS) were investigated. OS analysis was restricted to patients with severe COVID-19 (definition: hospitalization with need of oxygen or admission into an intensive care unit). CFR in patients with severe COVID-19 was 38.4%. OS was inferior for patients in all treatment categories compared to untreated (p < 0.001). Untreated patients had a lower risk of death (HR = 0.54, 95% CI:0.41-0.72). The risk of death was higher for older patients and those suffering from cardiac failure (HR = 1.03, 95% CI:1.02-1.04; HR = 1.79, 95% CI:1.04-3.07, respectively). Age, CLL-directed treatment, and cardiac failure were significant risk factors of OS. Untreated patients had a better chance of survival than those on treatment or recently treated.

Acute colonic pseudo-obstruction in elderly Report of a case.

A case of acute colonic obstruction in an elderly patient is presented, with a brief discussion about peculiar aspects to pseudo-obstruction and particularly chronic idiopathic intestinal pseudo-obstruction (CIIP), in which it was classified by pathologists. Clinical and therapeutic implications of this classification are also discussed. In authors'opinion, interesting aspects of the reported case are represented by the acute presentation, without previous symptoms at medical history and above all by the evidence of a recto-sigmoid junction intraoperatively palpable mass, mimicking ring-like neoplastic disease. The preoperative and intraoperative features led surgeons to perform a total colectomy with ileo-rectal anastomosis and high ligation of mesenteric inferior artery, with complete regional lymphectomy according to oncologic standard, but at histological examination the mass revealed to be due to considerable muscular tissue thickening, therefore to a benign condition. These features probably suggest the need of a better clinical and pathological classification of this difficult and still controversial matter, in order to achieve better outcomes and to avoid misdiagnosis and overtreatment. KEY WORDS: Intestinal obstruction, Pseudo-obstruction, Total colectomy.

The intracavitary electrocardiography method for tip location of jugular internal vein access device in infants of less than 5 kg: A pilot study.

PURPOSE:: This is a prospective observational study conducted by neonatologists in neonatal intensive care unit from Sant'Anna and San Sebastiano Hospital, Caserta, Italy. The objective of the study is to verify the feasibility of intracavitary electrocardiography method for tip location of central venous access device in infants of less than 5 kg and evaluate the accuracy of the method in comparison with post-procedural echocardiographical verification of the tip position. PATIENTS AND METHODS:: We enrolled 27 patients weighted between 0.660 and 5 kg, requiring central vascular access. Ultrasound-guided jugular internal vein access was used and after cannulation, we applied the intracavitary electrocardiography for tip location as well as post-procedural echocardiography. RESULTS:: No significant complication related to intracavitary electrocardiography occurred in the studied infants. The increase in P wave on intracavitary electrocardiography was detected in all cases (27/27). In only one case (false positive), the catheter had the tip out of cavoatrial junction-target zone (to post-procedural echocardiography). CONCLUSION:: The intracavitary electrocardiography method for tip location of central venous access device is safe and accurate in infants, as demonstrated by post-procedural comparative echocardiographic controls. As an alternative to echocardiography, not always achievable, the diffusion of intracavitary electrocardiography method could reduce X-ray exposition and complications of a malpositioned tip.

Monoclonal B-cell lymphocytosis: Does the elderly patient need a specialistic approach?

Monoclonal B-cell lymphocytosis (MBL) is defined by the presence of a monoclonal B-cell population in the peripheral blood (PB) at a concentration of <5 × 109/l and no signs or symptoms of a lymphoproliferative disorder. In around 75% of cases, the immunophenotype of the clonal B-cell expansions is superimposable to that of chronic lymphocytic leukemia (CLL), thus defined "CLL-like". Other cases may coexpress CD19, CD5, bright CD20, and lack CD23 ("atypical CLL"), while others are CD5-negative ("non-CLL"). Beside the immunophenotypic profile, a key distinction is based on the B-cell count, stratifying the MBL category in low (<0.5 × 109/l) or high-count (≥0.5 × 109/l). Low-count (LC) MBL is recognized in general population studies and it is not associated with lymphocytosis. High-count (HC) MBL is identified during the clinical work-up for lymphocytosis and carries a risk of progression to CLL requiring therapy of 1-2% per year in most series, warranting clinical monitoring over time. At the time of MBL diagnosis, the key point is the careful evaluation and exclusion of differential diagnoses. After the initial workup, the follow-up at a referral center by a hematologist would be desirable as, in addition to the obvious risk of progression to clinically relevant CLL, the appropriate management of MBL individuals should take into account the risk of developing infections, other cancers and autoimmune disorders. For those cases who indeed bear a risk, though limited, of clinical consequences, such as the majority of HC-MBL cases, current evidences suggest that they may benefit from a tailored and specialized approach.

The intracavitary electrocardiography method for positioning the tip of epicutaneous cava catheter in neonates: Pilot study.

PURPOSE:: The neonatologists of Sant'Anna and San Sebastiano Hospital of Caserta have carried out a pilot study investigating the safety, feasibility, and accuracy of intracavitary electrocardiography for neonatal epicutaneous cava catheter tip positioning. PATIENTS AND METHODS:: We enrolled 39 neonates (1-28 days of postnatal age or correct age lower than 41 weeks) requiring epicutaneous cava catheter in the district of superior vena cava (head-neck or upper limbs). Intracavitary electrocardiography was applicable in 38 neonates. RESULTS:: No significant complications related to intracavitary electrocardiography occurred in the studied neonates. The increase in P wave on intracavitary electrocardiography was detected in 30 cases. Of the remaining eight cases, six malpositioned catheters tipped out of cavoatrial junction-target zone (chest x-ray and echocardiographical control) and two were false negative (tip located in target zone). The match between intracavitary electrocardiography and x-ray was observed in 29/38 cases, and the same ratio between intracavitary electrocardiography and echocardiography was detected. CONCLUSION:: We conclude that the intracavitary electrocardiography method is safe and accurate in neonates as demonstrated in pediatric and adult patients. The applicability of the method is 97% and its feasibility is 79%. The overall accuracy is 76% but it rises to 97% if "peak" P wave is detected.

Assessment of ventilation during the performance of elective endoscopic-guided percutaneous tracheostomy: clinical evaluation of a new method.

STUDY OBJECTIVES: To evaluate the feasibility of uninterrupted translaryngeal open ventilation delivered through a pediatric, uncuffed endotracheal tube during percutaneous endoscopic tracheostomy (PET). DESIGN AND SETTING: Prospective, observational clinical study in a six-bed ICU of a university hospital. PATIENTS: Forty consecutive adult patients requiring an elective tracheostomy. INTERVENTIONS: We employed the basic Ciaglia technique with multiple dilators (n = 10), a single dilator (n = 15), and the Fantoni method (n = 15). During PET, pressure-controlled ventilation was maintained through an uncuffed, 4-mm inner-diameter pediatric tube. The fraction of inspired oxygen was 1.0. Ventilator settings were as follows: pressure-controlled ventilation, 40 cm H(2)O; respiratory rate, 25/min; inspiratory time, 1.2 s of inspiratory time (inspiratory/expiratory ratio, 1:1); and positive end-expiratory pressure, 0 cm H(2)O. MEASUREMENTS AND RESULTS: Measurements of arterial blood gas (ABG) tensions were obtained before the start of each tracheostomy and every 3 min during the procedure. An average of 8.28 +/- 2.28 ABG measurements were obtained from each patient (+/- SD). All patients were successfully assisted during performance of the tracheostomy, and no patient required ventilation through a cuffed endotracheal tube. The maximum increase in PaCO(2) was 8.49 +/- 5.50 mm Hg, and the maximum decrease in pH related to hypercarbia was 0.04 +/- 0.04. The PaO(2) increased in all patients (maximum change, 69.75 +/- 57.00 mm Hg; p < 0.01), and no patient had desaturation during the procedure. CONCLUSIONS: The technique that we propose for airway management during PET was safe and effective. A mild increase in PaCO(2) was not associated with significant metabolic and hemodynamic consequences, and an adequate PaO(2) was maintained throughout the study.

New-onset refractory status epilepticus mimicking herpes virus encephalitis.

New-onset refractory status epilepticus (NORSE) is a recently defined clinical entity that describes patients who present with status epilepticus of unclear etiology that is highly refractory to therapy. Magnetic resonance imaging (MRI) of NORSE usually discloses no specific abnormalities except for an occasional mild T2/FLAIR hyperintense signal of the mesial temporal lobe. Here, we report a peculiar case of NORSE in which brain MRI showed massive alteration of both temporal lobes, with features strongly supporting the diagnosis of herpes virus encephalitis, but lacking any laboratory evidence of viral infection in the blood and cerebrospinal fluid. It showed also striking signal alterations in the thalamus, which got worse in the course of the disease. This report emphasizes the possibility that seizure activity alone plays a critical role in both determining the disease and whether it will be self-sustaining.

Axial chordoma and parachordoma (soft tissue chordoma): two of a kind: report of two cases with primary diagnosis on fine-needle cytology samples.

This report concerns one case of sacrococcygeal chordoma and one case of parachordoma (soft-tissue chordoma) that were primarily diagnosed on fine-needle cytology (FNC) samples. Both neoplasms consisted of medium-sized epithelioid cells with eccentric, nucleolated nuclei, displaying abundant cytoplasm filled with bubbly vacuoles with refractile borders (physaliphorous cells). The neoplastic cells were embedded in an abundant extracellular substance staining metachromatically with Diff-Quik™. Both neoplasms had a typical clinical and instrumental presentation (primary sacrococcygeal tumor in a 58-year-old man and primary soft tissue mass of the hand palm and wrist in a 31-year-old man). The cytopathological findings in both the neoplasms were so similar as to be almost indistinguishable, and this similarity included the immunocytochemical findings. The deep similarity between these neoplasms indicates that the only pathological differences in the described cases probably reside in their different anatomical location and, perhaps, in different cytogenetic changes.

Immune dysregulation in atopic dermatitis.

Atopic dermatitis (AD) is a chronic, relapsing, highly pruritic, inflammatory skin disease characterized by cutaneous hyperreactivity to environmentals triggers. Recent data suggest the presence of two different forms of AD: an extrinsic AD with elevated IgE involving 70-80% of the patients and an intrinsic AD with serum IgE not elevated and no specific IgE. Patients with extrinsic AD have elevated Th2- and decreased Thl-expressing cells in the peripheral blood, with elevated IL-4 and IL-13 expression, as well as IL-5. On the contrary, the intrinsic AD is linked with much lower levels of IL-4 and IL-13. Genetic factors are involved in the control of the disease and in the intrinsic AD the same chromosomal regions seem to be associated with psoriasis susceptibility. The AD is characterized by a complex of immunological alterations involving interactions between IgE-bearing antigen-presenting cells, T-cell activation, mast-cell degranulation, keratinocytes, eosinophils, and a combination of immediate and cellular immune responses. Inflammatory dendritic epidermal cells constitute a distinct dendritic cells population that is mainly found in AD and could induce the Th2/Thl isotopic switch contributing to AD chronic phase. Therapy is based on interventation in the pathophysiology of atopic eczema and elimination of exogenous provocation factors.