Resident training to optimize patient-focused menopause management: a multispecialty menopause curriculum to enhance knowledge and preparedness.

OBJECTIVE: Surveys of residents in obstetrics and gynecology, internal medicine, and family medicine have demonstrated low levels of knowledge and comfort in treating patients with menopausal symptoms, suggesting a need for improved training during residency. To address this problem, we used a flipped classroom design to deliver a novel menopause curriculum for medical residents. The curriculum included six podcast episodes followed by an interactive case-based classroom session. We then assessed effects of the curriculum on the residents' knowledge and preparedness to manage menopause symptoms. METHODS: We targeted 200 residents (43 obstetrics and gynecology, 86 internal medicine, and 71 family medicine) from six residency programs from 2019 to 2020. Of these, 115 (58%) completed both pre- and postcurriculum assessments, including a 15-item knowledge test and self-ratings of their knowledge, comfort, and preparedness to manage menopause. RESULTS: Following the curriculum, the proportion of correctly answered knowledge questions rose from 60.8% to 79.1% (+18.3%; 95% confidence interval, 15.4-21.2; Cohen's d = 1.2). Improvement did not significantly differ by specialty or year of residency. There were higher gains for residents who listened to the entirety of all six podcast episodes ( b = 11.4, P < 0.001) and who attended the classroom session ( b = 11.6, P = 0.003). Residents' self-ratings of knowledge, comfort, and preparedness also improved following the curriculum across all medical specialties (Cohen's d = 0.47-1.2). Residents rated the podcast format as convenient (73%) and effective (65%) compared with an equivalent amount of reading. CONCLUSIONS: Pairing a podcast with a classroom discussion was found to be an effective combination for improving menopause knowledge.

Bridge to Health/Puente a la Salud: a pilot randomized trial to address diabetes self-management and social needs among high-risk patients.

Social needs contribute to persistent diabetes disparities; thus, it is imperative to address social needs to optimize diabetes management. The purpose of this study was to determine determine the feasibility and acceptability of health system-based social care versus social care + behavioral intervention to address social needs and improve diabetes self-management among patients with type 2 diabetes. Black/African American, Hispanic/Latino, and low-income White patients with recent hemoglobin A1C (A1C) ≥ 8%, and ≥1 social need were recruited from an integrated health system. Patients were randomized to one-of-two 6-month interventions: (a) navigation to resources (NAV) facilitated by a Patient Navigator; or (b) NAV + evidence-based nine-session diabetes self-management support (DSMS) program facilitated by a community health worker (CHW). A1C was extracted from the electronic health record. We successfully recruited 110 eligible patients (54 NAV; 56 NAV + DSMS). During the trial, 78% NAV and 80% NAV + DSMS participants successfully connected to a navigator; 84% NAV + DSMS connected to a CHW. At 6-month follow-up, 33% of NAV and 34% of NAV + DSMS participants had an A1C < 8%. Mean reduction in A1C was clinically significant in NAV (-0.65%) and NAV + DSMS (-0.72%). By follow-up, 89% of NAV and 87% of NAV + DSMS were successfully connected to resources to address at least one need. Findings suggest that it is feasible to implement a health system-based social care intervention, separately or in combination, with a behavioral intervention to improve diabetes management among a high-risk, socially complex patient population. A larger, pragmatic trial is needed to test the comparative effectiveness of each approach on diabetes-related outcomes.

Quantifying cancer risk from exposures to medical imaging in the Risk of Pediatric and Adolescent Cancer Associated with Medical Imaging (RIC) Study: research methods and cohort profile.

PURPOSE: The Risk of Pediatric and Adolescent Cancer Associated with Medical Imaging (RIC) Study is quantifying the association between cumulative radiation exposure from fetal and/or childhood medical imaging and subsequent cancer risk. This manuscript describes the study cohorts and research methods. METHODS: The RIC Study is a longitudinal study of children in two retrospective cohorts from 6 U.S. healthcare systems and from Ontario, Canada over the period 1995-2017. The fetal-exposure cohort includes children whose mothers were enrolled in the healthcare system during their entire pregnancy and followed to age 20. The childhood-exposure cohort includes children born into the system and followed while continuously enrolled. Imaging utilization was determined using administrative data. Computed tomography (CT) parameters were collected to estimate individualized patient organ dosimetry. Organ dose libraries for average exposures were constructed for radiography, fluoroscopy, and angiography, while diagnostic radiopharmaceutical biokinetic models were applied to estimate organ doses received in nuclear medicine procedures. Cancers were ascertained from local and state/provincial cancer registry linkages. RESULTS: The fetal-exposure cohort includes 3,474,000 children among whom 6,606 cancers (2394 leukemias) were diagnosed over 37,659,582 person-years; 0.5% had in utero exposure to CT, 4.0% radiography, 0.5% fluoroscopy, 0.04% angiography, 0.2% nuclear medicine. The childhood-exposure cohort includes 3,724,632 children in whom 6,358 cancers (2,372 leukemias) were diagnosed over 36,190,027 person-years; 5.9% were exposed to CT, 61.1% radiography, 6.0% fluoroscopy, 0.4% angiography, 1.5% nuclear medicine. CONCLUSION: The RIC Study is poised to be the largest study addressing risk of childhood and adolescent cancer associated with ionizing radiation from medical imaging, estimated with individualized patient organ dosimetry.

Changes in Visceral and Ectopic Adipose Tissue Stores Across Pregnancy and Their Relationship to Gestational Weight Gain.

BACKGROUND: Excessive gestational weight gain has been associated with increased total body fat (TBF), metabolic syndrome, and abdominal obesity. However, little is known about the relationship of gestational weight gain with changes in metabolically active visceral or ectopic (hepatic and skeletal muscle) lipid stores. OBJECTIVES: In a prospective study of 50 healthy, pregnant women, we assessed whether changes in weight were associated with changes in total, visceral, and ectopic lipid stores. METHODS: Participants (ages 19-39) were primarily White (84%). The mean preconception BMI was 25.8 kg/m2 (SD, 4.5 kg/m2; min-max, 17.1-35.9 kg/m2). Measurements were completed at visits 1 and 2 at means of 16 and 34 weeks gestation, respectively, and included TBF using BOD POD; abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) using MRI; and intrahepatic lipids (IHL), intramyocellular lipids (IMCL), and extramyocellular lipids (EMCL) using magnetic resonance spectroscopy. We used paired t-tests to examine changes in adipose tissue and Pearson's correlation to examine associations of adipose tissue changes and weight changes. We also examined whether changes in adipose tissue stores differed by preconception BMI (normal, overweight, and obese), using 1-way ANOVA. RESULTS: The TBF (mean change, +3.5 kg; 95% CI: 2.4-4.6 kg), SAT (mean change, +701 cm3; 95% CI: 421-981 cm3), VAT (mean change, +275 cm3; 95% CI: 170-379 cm3), and IHL (percentage water peak; median, +0.15; IQR = -0.01 to 0.32) values increased significantly; the IMCL and EMCL values did not change. Changes varied by BMI strata, with the least increase (or, for SAT, net loss) among women with obesity. Weight change was positively correlated with changes in TBF (r = 0.83; P < 0.001), SAT (r = 0.74; P < 0.001), and VAT (r = 0.63; P < 0.001) but not significantly correlated with changes in ectopic lipids (IHL, IMCL, and EMCL; -0.14 < r < 0.26). CONCLUSIONS: Preferential deposition of adipose tissue to the viscera in pregnancy, as seen in our sample, could serve an important metabolic function; however, excessive deposition in this region could negatively affect maternal health.

The association of bowel function, participation in life activities, and quality of life in rectal cancer survivors.

PURPOSE: To evaluate whether limited participation in life activities is associated with quality of life (QOL) in rectal cancer survivors, and if so, whether this association is independent of bowel function difficulties. METHODS: We surveyed rectal cancer survivors from four healthcare systems about their QOL, bowel function, and participation in life activities. Additional demographic and clinical variables were extracted from the electronic health record. We examined independent associations between bowel function, participation in life activities, and QOL, controlling for potential confounders. We also identified factors, including ostomy status, that correlate with participation in life activities. RESULTS: Of the 527 respondents, 52% were male, 80% were non-Hispanic white, and the mean age was 63. In fully adjusted models for all rectal cancer survivors, participation in life activities was positively associated with QOL, while bowel function was not. Bowel function retained an independent association with QOL for those who previously had an ostomy and were therefore more likely to have a low rectal anastomosis. Lower participation in life activities was correlated with lower self-reported physical and cognitive function, younger age, financial difficulty, and being non-Hispanic white. CONCLUSIONS: Rectal cancer survivors' participation in life activities was strongly associated with QOL, even when controlling for numerous confounders, including bowel function. Identifying ways to improve participation in life activities may be critical to developing rehabilitative and other supportive interventions that optimize QOL among rectal cancer survivors.

Positive predictive value and sensitivity of ICD-9-CM codes for identifying pediatric leukemia.

BACKGROUND: To facilitate community-based epidemiologic studies of pediatric leukemia, we validated use of ICD-9-CM diagnosis codes to identify pediatric leukemia cases in electronic medical records of six U.S. integrated health plans from 1996-2015 and evaluated the additional contributions of procedure codes for diagnosis/treatment. PROCEDURES: Subjects (N = 408) were children and adolescents born in the health systems and enrolled for at least 120 days after the date of the first leukemia ICD-9-CM code or tumor registry diagnosis. The gold standard was the health system tumor registry and/or medical record review. We calculated positive predictive value (PPV) and sensitivity by number of ICD-9-CM codes received in the 120-day period following and including the first code. We evaluated whether adding chemotherapy and/or bone marrow biopsy/aspiration procedure codes improved PPV and/or sensitivity. RESULTS: Requiring receipt of one or more codes resulted in 99% sensitivity (95% confidence interval [CI]: 98-100%) but poor PPV (70%; 95% CI: 66-75%). Receipt of two or more codes improved PPV to 90% (95% CI: 86-93%) with 96% sensitivity (95% CI: 93-98%). Requiring at least four codes maximized PPV (95%; 95% CI: 92-98%) without sacrificing sensitivity (93%; 95% CI: 89-95%). Across health plans, PPV for four codes ranged from 84-100% and sensitivity ranged from 83-95%. Including at least one code for a bone marrow procedure or chemotherapy treatment had minimal impact on PPV or sensitivity. CONCLUSIONS: The use of diagnosis codes from the electronic health record has high PPV and sensitivity for identifying leukemia in children and adolescents if more than one code is required.

Pregnancy and weaning regulate human maternal liver size and function.

During pregnancy, the rodent liver undergoes hepatocyte proliferation and increases in size, followed by weaning-induced involution via hepatocyte cell death and stromal remodeling, creating a prometastatic niche. These data suggest a mechanism for increased liver metastasis in breast cancer patients with recent childbirth. It is unknown whether the human liver changes in size and function during pregnancy and weaning. In this study, abdominal imaging was obtained in healthy women at early and late pregnancy and postwean. During pregnancy time points, glucose production and utilization and circulating bile acids were measured. Independently of weight gain, most women's livers increased in size with pregnancy, then returned to baseline postwean. Putative roles for bile acids in liver growth and regression were observed. Together, the data support the hypothesis that the human liver is regulated by reproductive state with growth during pregnancy and volume loss postwean. These findings have implications for sex-specific liver diseases and for breast cancer outcomes.

Bridge to Health/ Puente a la Salud: Rationale and design of a pilot feasibility randomized trial to address diabetes self-management and unmet basic needs among racial/ethnic minority and low-income patients.

INTRODUCTION: Racial/ethnic and socioeconomic disparities in diabetes prevalence and management persist. Unmet basic needs such as food insecurity and unstable housing interfere with optimal diabetes self-management. Bridge to Health/Puente a la Salud is a randomized pilot trial designed to examine the feasibility of testing the effectiveness of addressing unmet basic needs via navigation services versus navigation plus diabetes self-management support (DSMS) on improving diabetes-related outcomes among racial/ethnic minority and low-income patients with uncontrolled diabetes. MATERIAL AND METHODS: We recruited and randomized 110 African American, Hispanic, and Medicaid patients (any race/ethnicity) with diabetes and recent hemoglobin A1C ≥ 8% to one of two 6-month interventions: 1) Navigation only; or 2) Navigation + DSMS. In both arms, practice-embedded patient navigators help participants navigate social services and community-based resources to address unmet basic needs. In Navigation + DSMS, participants are also assigned to a community health worker (CHW) embedded in a local community-based organization who provides additional navigation support and delivers DSMS. A1C and unmet basic needs data are collected via routine lab and survey, respectively, at baseline and 6-month follow-up. Qualitative interviews with participants, health system leaders, CHWs, and patient navigators are conducted to explore intervention acceptability and determinants of implementation in a health care setting. DISCUSSION: Findings from this pilot feasibility study will enhance understanding about acceptability, preliminary clinical effectiveness, and facilitators and barriers to implementation of the Navigation only and Navigation + DSMS interventions and inform refinements of the overall study design for the larger, randomized clinical trial.

Improving management of the genitourinary syndrome of menopause: evaluation of a health system-based, cluster-randomized intervention.

BACKGROUND: Genitourinary symptoms are common in postmenopausal women and adversely affect the quality of life. National surveys and data collected from our healthcare system indicate that postmenopausal women with the genitourinary syndrome of menopause often fail to receive appropriate diagnosis or treatment. OBJECTIVE: To promote greater detection and treatment of the genitourinary syndrome of menopause, we created and tested a clinician-focused health system intervention that included clinician education sessions and a suite of evidence-based electronic health record tools. STUDY DESIGN: Using a cluster-randomized design, we allocated primary care (16) and gynecology (6) clinics to the intervention or control group. From September to November 2014, we provided training about the diagnosis and treatment of genitourinary syndrome of menopause in face-to-face presentations at each intervention clinic and in an online video. We developed clinical decision support tools in the electronic health record that contained an evidence-based, point-of-care knowledge resource, a standardized order set, and a checklist of patient education materials for the patient's after visit summary. The tools aimed to facilitate accurate diagnostic coding and prescribing (SmartSet, SmartRx) along with relevant patient information (SmartText). Clinicians who only performed visits at control clinics received no training or notification about the tools. Our primary outcome was vulvovaginal diagnoses made at well visits for women at the age of 55 years and older from November 15, 2014 to November 15, 2015. We also assessed urinary diagnoses, vaginal estrogen prescriptions, and use of the electronic tools. There was departmental support for the intervention but no prioritization within the healthcare system to incentivize change. RESULTS: In the 1-year period, 386 clinicians performed 14,921 well visits for women at the age of 55 years and older. Among the 190 clinicians who performed well visits in the intervention clinics, 109 (57.4%) completed either in-person or online educational training. The proportion of visits that included a vulvovaginal (7.2% vs 5.8%; odds ratio, 1.27; 95% confidence interval, 0.65-2.51) or urinary diagnosis (2.5% vs 3.1%; odds ratio, 0.79; 95% confidence interval, 0.55-1.13) or vaginal estrogen prescription (4.5% vs 3.7%; odds ratio, 1.24; 95% confidence interval, 0.63-2.46) did not differ between study arms. There was a significant interaction for primary care and gynecology, which revealed more vulvovaginal diagnoses by gynecology but not primary care intervention clinics (odds ratio, 1.63; 95% confidence interval, 1.15-2.31), but there was no significant interaction for prescriptions. Clinicians in the intervention clinics were more likely to use decision support tools than those in control clinics-SmartSet (22.2% vs 1.5%; odds ratio, 18.8; 95% confidence interval, 5.5-63.8) and SmartText for patient information (38.0% vs 24.4%; odds ratio, 1.91; 95% confidence interval, 1.10-3.34). A per-protocol analysis revealed similar findings. CONCLUSION: Overall, the intervention did not lead to more diagnoses or prescription therapy for postmenopausal genitourinary symptoms but did result in greater distribution of patient information. Gynecology clinicians were more likely to address genitourinary symptoms generally and were more likely to make a vulvovaginal diagnosis after the intervention. Further efforts for improving care should consider ongoing clinician education beginning with enhanced menopause curricula in residency training. Additional interventions to consider include greater access for postmenopausal women to gynecologic care, addressing treatment barriers, and development of national performance metrics.

Validation of a Ductal Carcinoma In Situ Biomarker Profile for Risk of Recurrence after Breast-Conserving Surgery with and without Radiotherapy.

PURPOSE: A major challenge in ductal carcinoma in situ (DCIS) treatment is selection of the most appropriate therapeutic approach for individual patients. We conducted an external prospective-retrospective clinical validation of a DCIS biologic risk signature, DCISionRT, in a population-based observational cohort of women diagnosed with DCIS and treated with breast-conserving surgery (BCS). EXPERIMENTAL DESIGN: Participants were 455 health plan members of Kaiser Permanente Northwest diagnosed with DCIS and treated with BCS with or without radiotherapy from 1990 to 2007. The biologic signature combined seven protein tumor markers assessed in formalin-fixed, paraffin-embedded tumor tissue with four clinicopathologic factors to provide a DCISionRT test result, termed decision score (DS). Cox regression and Kaplan-Meier analysis were used to measure the association of the DS, continuous (linear) or categorical (DS ≤ 3 vs. DS > 3), and subsequent total ipsilateral breast events and invasive ipsilateral breast events at least 6 months after initial surgery. RESULTS: In Cox regression, the continuous and categorical DS variables were positively associated with total and invasive breast event risk after adjustment for radiotherapy. In a subset analysis by treatment group, categorical Kaplan-Meier analyses showed at least 2-fold differences in 10-year risk of total breast events between the elevated-risk and low-risk DS categories. CONCLUSIONS: In this first external validation study of the DCISionRT test, the DS was prognostic for the risk of later breast events for women diagnosed with DCIS, following BCS.

Temporal Trends in the Incidence of Anogenital Warts: Impact of Human Papillomavirus Vaccination.

BACKGROUND: Studies in countries with high human papillomavirus (HPV) vaccination coverage have demonstrated marked reductions in anogenital wart (AGW) incidence. Our goal was to assess the impact of HPV vaccination in a population with suboptimal coverage by comparing AGW incidence trends in the years before and after vaccine introduction. METHODS: We conducted a retrospective analysis of AGW incidence trends using an ecologic study design among 11- through 39-year-olds enrolled at Kaiser Permanente Northwest. We defined incidence as the proportion of persons who had a new AGW diagnosis for each calendar year in the prevaccine periods (2000 through 2006 for female individuals, 2000 through 2010 for male individuals) and the postvaccine periods (2007 through 2016 for female individuals, 2011 through 2016 for male individuals). We also described cumulative HPV vaccination coverage. RESULTS: The average annual AGW incidence rates in the prevaccine periods were 27.8 per 10,000 in female individuals and 26.9 per 10,000 in male individuals. In the postvaccine periods, AGW incidence rates decreased by 31% (P < 0.001) in female individuals and 10% (P = 0.006) in male individuals; the largest reductions were observed in 15- to 19-year-old female individuals (67%, P < 0.001) and male individuals (45%, P < 0.001). Three dose HPV coverage rates were less than 50% in all age groups and both sexes. CONCLUSIONS: In a population of young adults with moderate HPV vaccination coverage, we observed declines in AGW incidence among both female and male year after the introduction of HPV vaccination. The largest incidence reductions were observed in 15- to 19-year-olds who were most likely to have been vaccinated.

Promoting evaluation capacity building in a complex adaptive system.

This study provides results from an NSF funded, four year, case study about evaluation capacity building in a complex adaptive system, the Nanoscale Informal Science Education Network (NISE Net). The results of the Complex Adaptive Systems as a Model for Network Evaluations (CASNET) project indicate that complex adaptive system concepts help to explain evaluation capacity building in a network. The NISE Network was found to be a complex learning system that was supportive of evaluation capacity building through feedback loops that provided for information sharing and interaction. Participants in the system had different levels of and sources of evaluation knowledge. To be successful at building capacity, the system needed to have a balance between both centralized and decentralized control, coherence, redundancy, and diversity. Embeddedness of individuals within the system also provided support and moved the capacity of the system forward. Finally, success depended on attention being paid to the control of resources. Implications of these findings are discussed.

Referring Hospitalized Smokers to Outpatient Quit Services: A Randomized Trial.

INTRODUCTION: Linking outpatient cessation services to bedside counseling for hospitalized smokers can improve long-run quit rates. Adding an assisted referral (AR) offer to a tobacco treatment specialist consult service fits the team approach to care in U.S. hospitals. DESIGN: A two-arm patient-randomized trial tested the effectiveness of adding an AR offer to outpatient smoking-cessation services and interactive voice recognition (AR+IVR) follow-up to a usual care (UC) tobacco-cessation consult for hospitalized smokers. SETTING/PARTICIPANTS: Over 24 months (November 2011-November 2013), 898 hospitalized adult smokers interested in quitting smoking were recruited from three large hospitals in the Portland, Oregon, area: an integrated group model HMO (n=622), a community hospital (n=195), and an academic health center (n=81). INTERVENTION: Tobacco treatment specialists identified smokers and provided an intensive bedside tobacco use assessment and cessation consultation (UC). AR+IVR recipients also received proactive ARs to available outpatient counseling programs and medications, and linked patients to a tailored IVR telephone follow-up system. MAIN OUTCOME MEASURES: The primary outcome was self-reported 30-day abstinence at 6-month follow-up. Secondary outcomes included self-reported and continuous abstinence and biochemically confirmed 7-day abstinence at 6 months. Follow-up was completed in September 2014; data were analyzed in 2015. RESULTS: A total of 597 and 301 hospitalized smokers were randomized to AR+IVR and UC, respectively. AR+IVR and UC recipients received 19.3 and 17.0 minutes of bedside counseling (p=0.372), respectively. Most (58%) AR+IVR patients accepted referrals for counseling, 43% accepted medications, and 28% accepted both. Self-reported 30-day abstinence for AR+IVR (17.9%) and UC (17.3%) were not statistically significant (p=0.569). Differences in 7-day, continuous, and biochemically confirmed abstinence by treatment group also were insignificant, overall and adjusting for site. CONCLUSIONS: Adding an AR to outpatient counseling and medications did not increase cigarette abstinence at 6 months compared to UC alone.

Lattice-matched transition metal disulfide intergrowths: the metallic conductors Ag2Te(MS2)3 (M = V, Nb).

We present new chalcogenide compounds, Ag2Te(MS2)3 (M = V, Nb), built up of alternating planes of [MS2] and [Ag2Te]. The Ag and Te atoms are linearly coordinated by S atoms in the [MS2] layers and held in place by covalent interactions. Structural polymorphism was found by single crystal X-ray diffraction studies, where long-range ordering or disorder of the Ag and Te atoms within the hexagonal planar [Ag2Te] layer yielded two distinct crystal forms. When the Ag and Te atoms are ordered, the two isostructural compounds crystallize in the non-centrosymmetric P62m space group, with a = 5.5347(8) Å, c = 8.0248(16) Å, and V = 212.89(6) Å(3) for α-Ag2Te(VS2)3 and a = 5.7195(8) Å, c = 8.2230(16) Å, and V = 232.96(6) Å(3) for α-Ag2Te(NbS2)3. For the occupationally disordered Ag/Te arrangement, a subcell of the ordered phase that crystallizes in the non-centrosymmetric P6m2 space group, with a = 3.2956(6) Å (=a(a)/(3)(1/2)), c = 8.220(2) Å, and V = 77.31(3) Å(3) for ß-Ag2Te(VS2)3, was identified. Furthermore, pair distribution function analysis revealed local distortions in the [Ag2Te] layer. Band structure calculations at the density functional theory level were carried out to investigate the electronic structure of Ag2Te(MS2)3. Electronic transport measurements on Ag2Te(MS2)3 show that they exhibit p-type metallic behavior. Thermal analyses and temperature-dependent powder X-ray diffraction studies were focused on the stability and transformation/decomposition of the Ag2Te(MS2)3 phases. Magnetic susceptibility data are also reported. The new intercalated Ag2Te(MS2)3 system features a unique hypervalent Te with a three-center, four-electron bonding environment isoelectronic to that found in I3(-).

Structures and phase transitions of CePd3+xGa8-x: new variants of the BaHg11 structure type.

New distorted variants of the cubic BaHg11 structure type have been synthesized in Ga flux. Multiple phases of CePd3+xGa8-x, which include an orthorhombic Pmmn structure (x = 3.21(2)), a rhombohedral R3m structure (x = 3.13(4)), and a cubic Fm3m superstructure (x = 2.69(6)), form preferentially depending on reaction cooling rate and isolation temperature. Differential thermal analysis and in situ temperature-dependent powder X-ray diffraction patterns show a reversible phase transition at approximately 640 °C between the low temperature orthorhombic and rhombohedral structures and the high temperature cubic superstructure. Single crystal X-ray diffraction experiments indicate that the general structure of BaHg11, including the intersecting planes of a kagomé-type arrangement of Ce atoms, is only slightly distorted in the low temperature phases. A combination of Kondo, crystal electric field, and magnetic frustration effects may be present, resulting in low temperature anomalies in magnetic susceptibility, electrical resistivity, and heat capacity measurements. In addition to CePd3+xGa8-x, the rare earth analogues REPd3+xGa8-x, RE = La, Nd, Sm, Tm, and Yb, were successfully synthesized and also crystallize in one of the lower symmetry space groups.

Development and loss of ferromagnetism controlled by the interplay of Ge concentration and Mn vacancies in structurally modulated Y4Mn(1-x)Ga(12-y)Ge(y).

The cubic intermetallic phase Y(4)Mn(1-x)Ga(12-y)Ge(y) (x = 0-0.26, y = 0-4.0) has been isolated from a molten gallium flux reaction. It presents a rare example of a system where ferromagnetism can be induced by controlling the vacancies of the magnetic centers. The Y(4)PdGa(12) type crystal structure is made up of a corner-sharing octahedral network of Ga and Ge atoms with Mn atoms at the centers of half the octahedra and Y atoms in the voids. At the highest Ge concentration, y = 4.0, the Mn site is nearly fully occupied, x = 0.05, and the samples are paramagnetic. At a lower Ge concentration, y = 1.0, Mn deficiency develops with x = 0.10. Surprisingly, strong ferromagnetism is observed with T(c) = 223 K. When Ge is excluded, y = 0, Mn is substantially deficient at x = 0.26 and ferromagnetism is maintained with a T(c) of approximately 160 K. In addition, a 6-fold modulated superstructure appears owing to an ordered slab-like segregation of Mn atoms and vacancies. Corresponding bond distortions propagate throughout the octahedral Ga network. Structure-property relationships are examined with X-ray and neutron diffraction, magnetic susceptibility, and electrical resistivity measurements.

Distortion and charge density wave in the Ga square net coupled to the site occupancy wave in YCo0.88Ga3Ge.

YCo 0.88Ga 3Ge has an incommensurately modulated structure that was solved with (3 + 1)D superspace techniques. YCo 0.88Ga 3Ge crystallizes in the orthorhombic superspace group Immm(alpha00)00 s with unit cell constants of a = 4.1639(4), b = 4.1639(4), c = 23.541(2) A and a modulation vector of q = 0.3200(4) a* at 293 K. The incommensurate modulation, which creates a very large supercell ( approximately 25 fold), arises from a charge density wave (CDW) in the square net of Ga atoms that is coupled with a site occupancy wave (SOW) of Co atoms. The distorted Ga net features polygallide ribbons, chains, as well as single atoms. Temperature dependent crystallographic studies of the structure from 100-500 K indicate that the CDW is "locked in". Electrical conductivity and thermopower measurements in the temperature range of 300-500 K show that YCo 0.88Ga 3Ge is a poor metal.