Discovery of New Isotopes

Using the fusion-evaporation reaction ^{106}Cd(^{58}Ni,4n)^{160}Os and the gas-filled recoil separator SHANS, two new isotopes _{76}^{160}Os and _{74}^{156}W have been identified. The α decay of ^{160}Os, measured with an α-particle energy of 7080(26) keV and a half-life of 201_{-37}^{+58} µs, is assigned to originate from the ground state. The daughter nucleus ^{156}W is a ß^{+} emitter with a half-life of 291_{-61}^{+86} ms. The newly measured α-decay data allow us to derive α-decay reduced widths (δ^{2}) for the N=84 isotones up to osmium (Z=76), which are found to decrease with increasing atomic number above Z=68. The reduction of δ^{2} is interpreted as evidence for the strengthening of the N=82 shell closure toward the proton drip line, supported by the increase of the neutron-shell gaps predicted in theoretical models.

Supplemental feeding of deer reduces tick abundance in Mississippi, U.S.A.

Prior research on baiting and feeding of wildlife found changes in habitat and the concentration of wildlife on a local scale (e.g., hundreds of meters). Since changes in habitat and host density affect ticks, feeding wildlife may lead to changes in tick and tick-borne disease ecology. We quantified the effect of feeding deer on ticks and tick-borne diseases at 79 pairs of sites with and without deer feeders during May-August of 2019 and 2020. We captured 0.4 fewer adult (p<0.05) and 1.2 fewer nymphal ticks (p=0.01) at feeder sites. This effect intensified over time with one fewer tick trapped at old feeders (≥5 years) compared to new feeders (<5 years, p<0.05). Greater daily wildlife visitation rates (p<0.001) may have allowed questing ticks to encounter hosts more readily. Most collected ticks were Amblyomma americanum (92.8%), a vector of Ehrlichia and Rickettsia pathogens, though prevalence of these pathogens did not differ (p>0.13) at a local scale. Supplemental deer feeding appears to influence ticks, possibly due to decreased tick habitat and increased wildlife use around feeders. Our findings indicate feeding does not lead to increased prevalence of Ehrlichia or Rickettsia bacteria within A. americanum locally.

Research on the establishment and application of protein fingerprint spectrum database of Burkholderia pseudomallei in Hainan Province China.

Burkholderia pseudomallei (B. pseudomallei) is the etiologic agent of melioidosis. The aim of this study was to establish a SuperSpectrum of B. pseudomallei in Hainan and evaluate its application value in the rapid identification of clinical isolates of B. pseudomallei. In total, 99 isolates of B. pseudomallei were obtained between 2010-2019 in different regions of Hainan Province, multilocus sequence typing (MLST) was performed, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was applied for spectrum acquisition. A SuperSpectrum was created based on the selection of 80 representative average spectra for 17 isolates of B. pseudomallei. Then we validated the SuperSpectra with 82 strains of B. pseudomallei, eight strains of Burkholderia thailandensis, two strains of Burkholderia cepacia, one strain of Burkholderia cenocepacia and one strain of Burkholderia multivorans, as well as one strain of Burkholderia gladioli identified by MLST typing, 16S rRNA gene sequencing and Vitek 2 Compact. The results showed that all samples in this study were confirmed at the species level. Protein fingerprints spectra showed that specific peaks occurred in B. pseudomallei from the Hainan region. The result of clustering typing indicated that B. pseudomallei and its closely related species could be well classified by MALDI-TOF MS at the protein level.

New α-Emitting Isotope

A new α-emitting isotope ^{214}U, produced by the fusion-evaporation reaction ^{182}W(^{36}Ar,4n)^{214}U, was identified by employing the gas-filled recoil separator SHANS and the recoil-α correlation technique. More precise α-decay properties of even-even nuclei ^{216,218}U were also measured in the reactions of ^{40}Ar, ^{40}Ca beams with ^{180,182,184}W targets. By combining the experimental data, improved α-decay reduced widths δ^{2} for the even-even Po-Pu nuclei in the vicinity of the magic neutron number N=126 are deduced. Their systematic trends are discussed in terms of the N_{p}N_{n} scheme in order to study the influence of proton-neutron interaction on α decay in this region of nuclei. It is strikingly found that the reduced widths of ^{214,216}U are significantly enhanced by a factor of two as compared with the N_{p}N_{n} systematics for the 84≤Z≤90 and N<126 even-even nuclei. The abnormal enhancement is interpreted by the strong monopole interaction between the valence protons and neutrons occupying the π1f_{7/2} and ν1f_{5/2} spin-orbit partner orbits, which is supported by the large-scale shell model calculation.

Short-Lived α-Emitting Isotope

A new, very short-lived neutron-deficient isotope ^{222}Np was produced in the complete-fusion reaction ^{187}Re(^{40}Ar,5n)^{222}Np, and observed at the gas-filled recoil separator SHANS. The new isotope ^{222}Np was identified by employing a recoil-α correlation measurement, and six α-decay chains were established for it. The decay properties of ^{222}Np with E_{α}=10016(33) keV and T_{1/2}=380_{-110}^{+260} ns were determined experimentally. The α-decay systematics of Np isotopes is improved by adding the new data for ^{222}Np, which validates the N=126 shell effect in Np isotopes. The evolution of the N=126 shell closure is discussed in the neutron-deficient nuclei up to Np within the framework of α-decay reduced width.

New Isotope

A new short-lived neutron-deficient isotope ^{220}Np was synthesized in the fusion-evaporation reaction ^{185}Re(^{40}Ar,5n)^{220}Np at the gas-filled recoil separator SHANS. Based on the measurement of the correlated α-decay chains, the decay properties of ^{220}Np with E_{α}=10040(18) keV and T_{1/2}=25_{-7}^{+14} µs were determined, which are in good agreement with theoretical predictions. From the new experimental results coupled with the recently reported α-decay data of ^{219,223}Np, the α-decay systematics for Np isotopes around N=126 was established, which allows us for the first time to test the robustness of the N=126 shell closure in Z=93 Np isotopes. The results also indicate that, in the region of nuclei with Z≥83, the proton drip line has been reached for all odd-Z isotopes up to Np.

[Analysis on brucellosis epidemiological characteristics in Hainan province].

Objective: To understand the epidemiological characteristics of brucellosis in Hainan province. Methods: Automatic microbial identification system of Vitek 2 compact was used for the preliminary identification of 16 brucellosis cases in Hainan province from 2012 to 2017, and further confirmation was performed with traditional biological typing methods. The epidemiological and clinical characteristics of the patients were analyzed in combination with the results of serological and etiological tests for raised livestock. Results: Vitek 2 compact detection results showed that 12 strains were Brucella (B.) melitensis and 4 strains were Ochrobactrum anthropi. Traditional biological typing methods showed that 11 strains were B. melitensis biovar 3 and 5 strains were B. suis biovar 3. Sixteen cases were found in Dongfang, Lingao, Haikou, Wanning, Ledong and Ding'an with 1 case in 2012, 2 cases in 2013, 4 cases in 2014, 1 case in 2015, 2 cases in 2016 and 6 cases in 2017 respectively. At the same time, 745 sheep serum samples from the epidemic area (Dongfang) were collected for Brucella serum antibody detection, in which 47 were positive (6.3%). And B. melitensis biovar 3 was isolated from samples collected from sick sheep in Dongfang. Conclusions: Vitek 2 compact is an simple and convenient method for Brucella identification, but it cannot replace traditional biological typing methods yet. The major epidemic strains of Brucella in Hainan were B. melitensis biovar 3 and B. suis biovar 3. The epidemic of brucellosis in Dongfang in 2017 indicated that brucellosis had spread from animal to human in Hainan, and it is very important to strengthen the prevention and control of brucellosis in Hainan.

Biodegradable interstitial release polymer loading a novel small molecule targeting Axl receptor tyrosine kinase and reducing brain tumour migration and invasion.

Glioblastoma multiforme (GBM) is the most common and aggressive brain tumour. The neoplasms are difficult to resect entirely because of their highly infiltration property and leading to the tumour edge is unclear. Gliadel wafer has been used as an intracerebral drug delivery system to eliminate the residual tumour. However, because of its local low concentration and short diffusion distance, patient survival improves non-significantly. Axl is an essential regulator in cancer metastasis and patient survival. In this study, we developed a controlled-release polyanhydride polymer loading a novel small molecule, n-butylidenephthalide (BP), which is not only increasing local drug concentration and extending its diffusion distance but also reducing tumour invasion, mediated by reducing Axl expression. First, we determined that BP inhibited the expression of Axl in a dose- and time-dependent manner and reduced the migratory and invasive capabilities of GBM cells. In addition, BP downregulated matrix metalloproteinase activity, which is involved in cancer cell invasion. Furthermore, we demonstrated that BP regulated Axl via the extracellular signal-regulated kinases pathway. Epithelial-to-mesenchymal transition (EMT) is related to epithelial cells in the invasive migratory mesenchymal cells that underlie cancer progression; we demonstrated that BP reduced the expression of EMT-related genes. Furthermore, we used the overexpression of Axl in GBM cells to prove that Axl is a crucial target in the inhibition of GBM EMT, migration and invasion. In an in vivo study, we demonstrated that BP inhibited tumour growth and suppressed Axl expression in a dose-dependent manner according to a subcutaneous tumour model. Most importantly, in an intracranial tumour model with BP wafer in situ treatment, we demonstrated that the BP wafer not only significantly increased the survival rate but also decreased Axl expression, and inhibited tumour invasion. These results contribute to the development of a BP wafer for a novel therapeutic strategy for treating GBM invasion and increasing survival in clinical subjects.

[Tympanum meningioma: one case report].

Clinical presatation: right ear tinnitus, hearing loss, headache for 1 year with intermittent vertigo for 9 months. Specialized examination: right ear tympanum hyperemia and edema, right ear severe conduction deafness, left ear mild hearing loss. The average threshold: right ear 65 dB, the left ear 35 dB. Imaging examination: CT showed the soft tissue density mass in the right ear tympanum, part of the ear bone obscurity, superior wall of the tympanic cavity attenuation, tympanic sinus entry is not expanding. Imaging diagnosis: chronic otitis media with cholesteatoma formation. Postoperative diagnosis: meningioma.

Gross patterns of umbilical cord coiling: correlations with placental histology and stillbirth.

INTRODUCTION: The purpose of this study was to define gross patterns of umbilical cord hypercoiling and determine correlations with histological features in the placenta and/or perinatal outcomes such as stillbirth. METHODS: Gross images of placentas with hypercoiled umbilical cords (>3 coils/10 cm) were assigned a major umbilical coiling pattern and the direction (right or left) of the coiling. Definitions of 4 gross coiling patterns were established: undulating, rope, segmented, and linked, each with progressively deeper indentations in cord diameter. Outcome variables obtained from placental pathology reports and maternal medical records included histological abnormalities indicative of significant chronic fetal vascular obstruction, such as fetal vascular thrombi, avascular villi, villous stromal-vascular karyorrhexis, and fetal thrombotic vasculopathy, and stillbirth. RESULTS: 318 placentas/umbilical cords met inclusion criteria. The rope pattern was the most common (52%), followed by the undulating (26%), segmented (19%) and linked (3%) patterns. The segmented and linked gross coiling patterns were significantly correlated with histologic evidence of chronic fetal vascular obstruction and stillbirth, when compared with the ropeand undulating patterns. Cords with right twists were also significantly correlated with histologic evidence of chronic fetal vascular obstruction and stillbirth when compared with cords with left twists. The number of cord coils per 10 cm did not correlate with any of the outcome variables. CONCLUSIONS: Among hypercoiled umbilical cords, specific gross patterns of coiling can be recognized, and patterns with the most significant indentation or pinching of the cord diameter are associated with histological evidence of chronic fetal vascular obstruction and stillbirth.

Trajectories of femoral neck strength in relation to the final menstrual period in a multi-ethnic cohort.

UNLABELLED: The purpose of this study was to describe the evolution of femoral neck strength relative to load across the menopause transition. It declined significantly over the 10 years bracketing the final menstrual period, and the rate of decline was modified by body mass index, race/ethnicity, and smoking status. INTRODUCTION: Composite indices of femoral neck strength, which integrate dual energy X-ray absorptiometry (DXA)-derived bone mineral density and bone size with body size, are inversely associated with hip fracture risk. Our objective was to describe longitudinal trajectories of the strength indices across the menopausal transition. METHODS: Data came from the Study of Women's Health Across the Nation; participants were pre- or early peri-menopausal, ages 42-53 at baseline, and were followed up for 9.1 ± 1.8 years. Composite indices of femoral neck strength in different failure modes (compression, bending, and impact) were created in 921 women who had three or more hip DXA scans and had definable final menstrual period (FMP) dates. We used mixed effects models to fit piecewise linear growth curves to the baseline-normalized strength indices as a function of time to/after the FMP. RESULTS: Compression and impact strength indices did not decline until 1 year prior to the FMP, and declined rapidly thereafter, with some slowing of decline 1 year after the FMP. Bending strength index increased slightly until 2 years prior to the FMP, then plateaued, and began to decline at the FMP. Mean decline in strength indices over 10 years was 6.9 % (compression), 2.5 % (bending), and 6.8 % (impact). Women with higher body mass index had larger declines in two of the three indices. Other major modifiers of rates of decline were race/ethnicity and smoking status. CONCLUSIONS: Femoral neck strength relative to load declines significantly during the menopausal transition, with declines commencing 1 to 2 years prior to the FMP.

Psychometric comparisons of three measures for assessing motor functions in preschoolers with intellectual disabilities.

BACKGROUND: Deficit in motor performance is common in children with intellectual disabilities (ID). A motor function measure with sound psychometric properties is indispensable for clinical and research use. The purpose of this study was to compare the psychometric properties of three commonly used clinical measures for assessing motor function in preschoolers with ID: the Bruininks-Oseretsky Test of Motor Proficiency-Second Edition, the Movement Assessment Battery for Children-Second Edition and the Peabody Developmental Motor Scale-Second Edition (PDMS-2). METHOD: One hundred and ninety-one children aged 3-6 years with ID were evaluated with the three measures at three time points: two baseline measurements with a 1-week interval before the intervention, and a follow-up measurement after 6 months of paediatric rehabilitation programme. One hundred and forty-one participants completed all of the assessments. The distribution (ceiling and floor effects) and reliability (internal consistency and test-retest reliability) of each measure were examined. Concurrent validity, predictive validity, and responsiveness were examined as well. RESULTS: All measures, except for the PDMS-2, had significant floor effects or ceiling effects at one or more time points. The three measures had good internal consistency (Cronbach α ≥ 0.86) and test-retest reliability (intraclass correlation coefficient ≥ 0.96). The Spearman ρ correlation coefficient for each pair of the three measures was ≥ 0.80, indicating high concurrent validity. The predictive validity of the three measures was satisfactory (Spearman ρ ≥ 0.52). The responsiveness of the three measures was moderate (0.47 ≤ effect size ≤ 0.74). The minimal detectable changes of the three measures were satisfactory. CONCLUSIONS: All three measures showed sufficient reliability, validity and responsiveness in preschoolers with ID, but the PDMS-2 is recommended for its superior psychometric properties.

Simulation of pneumoperitoneum for laparoscopic surgery planning.

Laparoscopic surgery planning is usually realized on a preoperative image that does not correspond to the operating room conditions. Indeed, the patient undergoes gas insufflation (pneumoperitoneum) to allow instrument manipulation inside the abdomen. This insufflation moves the skin and the viscera so that their positions do no longer correspond to the preoperative image, reducing the benefit of surgical planning, more particularly for the trocar positioning step. A simulation of the pneumoperitoneum influence would thus improve the realism and the quality of the surgical planning. We present in this paper a method to simulate the movement of skin and viscera due to the pneumoperitoneum. Our method requires a segmented preoperative 3D medical image associated to realistic biomechanical parameters only. The simulation is performed using the SOFA simulation engine. The results were evaluated using computed tomography [CT] images of two pigs, before and after pneumoperitoneum. Results show that our method provides a very realistic estimation of skin, viscera and artery positions with an average error within 1 cm.

Do the effects of APOE-ε4 on cognitive function and decline depend upon vitamin status? MacArthur Studies of Successful Aging.

OBJECTIVES: To investigate whether gene nutrient interactions influence the risk of cognitive dysfunction among older persons. DESIGN: We performed a cross-sectional and longitudinal study of 499 adults aged 70-79 years from the Mac Arthur Study of Successful Aging to determine the effect of apolipoprotein E (APOE) in conjunction with plasma levels of homocysteine and of the related B vitamins on multiple domains of cognitive function and cognitive decline. RESULTS: The APOE-ε4 allele, high homocysteine, low folate, and low vitamin B6 levels were each associated with worse baseline cognitive function, and all but B6 and B12 were associated with seven year cognitive decline. There was no interaction between APOE-ε4, and homocysteine, folate, B6, or B12 in predicting baseline cognitive function (p-values: 0.12-0.94) or longitudinal decline (p-values: 0.52-0.91). Of five cognitive subtests, there was a significant interaction between the ε4 allele, low B6, and decline in correct naming response items (p=0.04). CONCLUSION: B vitamin status does not influence the risk of overall cognitive dysfunction in ε4 allele affected older adults.

A cost effective simulator for education of ultrasound image interpretation and probe manipulation.

Ultrasonography is the lowest cost no risk medical imaging technique. However, reading an ultrasonographic (US) image as well as performing a good US probe positioning remain difficult tasks. Education in this domain is today performed on patients, thus limiting it to the most common cases. In this paper, we present a cost effective simulator that allows US image practice and realistic probe manipulation from CT data. More precisely, we tackle the issue of providing a realistic interface for the probe manipulation with a basic haptic feedback.

The reliability and validity of three non-radiological measures of thoracic kyphosis and their relations to the standing radiological Cobb angle.

UNLABELLED: Hyperkyphosis is implicated in a mounting list of negative outcomes, including higher mortality. Hyperkyphosis research is hindered due to difficulties inherent in its measurement. By showing that three clinical measures of kyphosis are suitable for use in large scale, longitudinal, hyperkyphosis studies, we will facilitate much needed research in this field. INTRODUCTION: The objective of this study is to describe the reliability of three non-radiological kyphosis measures (Debrunner kyphosis angle, flexicurve kyphosis index, and flexicurve kyphosis angle) and their validity compared to the Cobb angle and to approximate a Cobb angle from non-radiological kyphosis measures. METHODS: We analyzed data from 113 participants aged ≥ 60 years with kyphosis angle ≥ 40°. Cobb angle was measured on a standing lateral thoracolumbar radiograph using bounds at T4 and T12. Non-radiological measures of kyphosis were made three times by a single rater and a 4th time by a blinded second rater. RESULTS: Intra- and inter-rater reliabilities for non-radiological assessments were high (intra-class correlations of 0.96 to 0.98) and did not differ from each other. Pearson correlations, estimating validity, ranged from 0.62 to 0.69 and did not differ. The Debrunner angle was close to the Cobb angle, with scaling factor of 1.067 and an offset of 5°. The Flexicurve kyphosis angle had to be scaled by 1.53 to obtain the equivalent Cobb angle. The scaling factor for the Flexicurve kyphosis index to Cobb angle was 315, with an offset of 5°. Compared to the measured Cobb angle, Cobb angles predicted using the non-radiological measures had similar magnitude errors (standard deviations of the differences ranging between 10.24 and 11.26). CONCLUSIONS: Each non-radiological measurement had similar reliability and validity. Low cost, ease of use, and robustness to variations in spine contour argue for the Flexicurve in longitudinal kyphosis assessments. The approximate conversion factors provided will permit translation of non-radiological measures to Cobb angles.

Prognostic factors in pathological stage IB nonsmall cell lung cancer greater than 3 cm.

Significant heterogenity of stage IB (sixth edition of the TNM staging system) nonsmall cell lung cancer (NSCLC) has been identified, and further subclassification according to tumour size has been proposed. The aim of this study is to evaluate the prognostic factors in patients with resected stage IB NSCLC > 3 cm. From January 1980 to December 2000, 525 patients underwent surgical resection for stage IB NSCLC > 3 cm at Taipei Veterans General Hospital, Taipei, Taiwan. The clinicopathological characteristics of these patients were retrospectively reviewed. The 5- and 10-yr overall survival rates were 44.9% and 27.3%, respectively. Age (p < 0.001), tumour size (p = 0.002), extent of pulmonary resection (p = 0.002), histological type (p = 0.005) and number of mediastinal lymph nodes dissected/sampled (p = 0.004) were significant predictors for overall survival in multivariate analysis. Patients with tumour size >7 cm, or > 5 to ≤ 7 cm, had a worse survival than those with tumour size > 3 to ≤ 5 cm. However, visceral pleural invasion did not influence overall survival. Stage IB NSCLC with a diameter > 3 cm may be subclassified according to tumour size regardless of visceral pleural invasion.

Prediction of severe neurogenic bowel dysfunction in persons with spinal cord injury.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: To analyze the predictors of severe neurogenic bowel dysfunction (NBD) in persons with spinal cord injury (SCI). SETTING: The Kaohsiung Medical University Hospital, Taiwan. METHODS: Two questionnaires-the NBD score and the Beck Depression Inventory second edition-were sent to 232 persons with SCI by mail. The demographic factors and injury-related factors were recorded to evaluate any relationships with severe NBD. The associations between the severity of NBD and psychological condition were also measured. RESULTS: In all, 39.4% of the respondents suffered from severe NBD. Multiple logistic regression analysis showed that those with a cervical injury (odds ratios (OR)=10.5, 95% confidence interval (CI) 1.6-67.7) or a thoracic injury (OR=7.1, 95% CI 1.2-40.3) had a higher risk of severe NBD than those with a lumbar injury. Persons with American Spinal Injury Association (ASIA) A had a 12.8-fold higher risk of severe NBD than persons with ASIA D (OR=12.8, 95% CI 3.3-50.1). Longer duration of injury (> or =10 years) was another risk factor of severe NBD. Moderate-to-severe depression was associated with reduced bowel function. CONCLUSIONS: This study showed that high level of cord lesion, completeness of cord injury and longer duration of injury (> or =10 years) could predict the severity of NBD in patients with SCI.

The mechanisms of failure of totally implantable central venous access system: analysis of 73 cases with fracture of catheter.

BACKGROUND: Totally implantable access ports are often used for the administration of chemotherapy or prolonged intravenous infusions in patients with cancer. The technique has been well described. However, some complications would happen. The pinch-off-syndrome is one of these complications. We report another presentation of pinch-off-syndrome and how to prevent. METHODS: From January 2005 to December 2007, 73 patients of catheter fracture were collected. The duration of Port-A implantation ranged from January 2003 to October 2007. During this period, 3358 port-catheters were implanted. There were three brands of Port-A implanted included 46% BardPort (Bard, Salt Lake City, UT, USA), 42% A Port (Arrow international, Reading, PA, USA) and 12% PORT-A CATH (Deltec, St. Paul, MN, USA). RESULTS: The most common clinical presentation was difficulty in injection in 32 cases (43.8%). The incidence of brand C was far lower than brand A and B. The most common site of fracture was at the proximal part (anastomosis between injection port and catheter) in 68 cases (93.2%). The incidence of fracture of Port-A was 6 in 738 (0.81%) in cut-down method; 67 in 2620 (2.56%) in percutaneous subclavian method. Most of the cases (34%) were no more than six months. CONCLUSION: The most frequent location of fracture Port-A was in proximal part - anastomosis between injection port and catheter. The cause of easily fracture may be associated with pinch-off-syndrome and design of Port-A. This kind of fracture could be prevented by cut-down method and fixed one stitch in proximal part.

Effects of the menopause transition and hormone use on cognitive performance in midlife women.

BACKGROUND: There is almost no longitudinal information about measured cognitive performance during the menopause transition (MT). METHODS: We studied 2,362 participants from the Study of Women's Health Across the Nation for 4 years. Major exposures were time spent in MT stages, hormone use prior to the final menstrual period, and postmenopausal current hormone use. Outcomes were longitudinal performance in three domains: processing speed (Symbol Digit Modalities Test [SDMT]), verbal memory (East Boston Memory Test [EBMT]), and working memory (Digit Span Backward). RESULTS: Premenopausal, early perimenopausal, and postmenopausal women scored higher with repeated SDMT administration (p < or = 0.0008), but scores of late perimenopausal women did not improve over time (p = 0.2). EBMT delayed recall scores climbed during premenopause and postmenopause (p < or = 0.01), but did not increase during early or late perimenopause (p > or = 0.14). Initial SDMT, EBMT-immediate, and EBMT-delayed tests were 4%-6% higher among prior hormone users (p < or = 0.001). On the SDMT and EBMT, compared to the premenopausal referent, postmenopausal current hormone users demonstrated poorer cognitive performance (p < or = 0.05) but performance of postmenopausal nonhormone users was indistinguishable from that of premenopausal women. CONCLUSIONS: Consistent with transitioning women's perceived memory difficulties, perimenopause was associated with a decrement in cognitive performance, characterized by women not being able to learn as well as they had during premenopause. Improvement rebounded to premenopausal levels in postmenopause, suggesting that menopause transition-related cognitive difficulties may be time-limited. Hormone initiation prior to the final menstrual period had a beneficial effect whereas initiation after the final menstrual period had a detrimental effect on cognitive performance.