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J Shumway

Publications and source records attributed to J Shumway.

5 recordsLinked to original sources

Theory of excitonic spectra and entanglement engineering in dot molecules.

We present results of correlated pseudopotential calculations of an exciton in a pair of vertically stacked InGaAs/GaAs dots. Competing effects of strain, geometry, and band mixing lead to many unexpected features missing in contemporary models. The first four excitonic states are all optically active at small interdot separation, due to the broken symmetry of the single-particle states. We quantify the degree of entanglement of the exciton wave functions and show its sensitivity to interdot separation. We suggest ways to spectroscopically identify and maximize the entanglement of exciton states.

Journal Article↗

Tocolysis with advanced cervical dilatation.

OBJECTIVE: To assess the feasibility and potential benefit of delaying delivery in women with advanced preterm labor. METHODS: Two hundred fifty-seven gravidas with intact membranes and preterm labor at cervical dilatations of at least 3 cm were studied. Women were excluded if they had premature rupture of membranes, gestational age less than 24 or more than 35.9 weeks, complete cervical dilatation, severe hemorrhage, chorioamnionitis, and triplets or higher-order gestations. Management consisted of tocolysis with intravenous magnesium sulfate as the primary agent, antenatal steroids, antibiotics, and amniocentesis. The primary endpoint was delay to delivery interval. Statistical analyses by cervical dilatation were performed using the Pearson chi2 test and a nonparametric test of trend. RESULTS: Eighty-one percent of pregnancies were referrals in utero from outlying hospitals. Delivery was delayed 24 hours or longer in 74% and beyond 48 hours in 60% of cases. Among 229 women who delivered at our center, 21% remained undelivered after 1 week. Evaluating delay as a function of cervical dilatation, trend analysis found a highly significant inverse relationship (P < .001). Among women dilated 5 cm, 46% delivered beyond 48 hours. Among those dilated 6 cm or more, 19% delivered beyond 48 hours. Mild pulmonary edema developed in five percent, and all responded promptly to medical interventions. Chorioamnionitis developed in eight percent. CONCLUSION: Delaying delivery 24-48 hours to allow antenatal steroid use or other interventions is possible in women with advanced preterm labor.

Cervix Uteri↗

Medical malpractice involving radiologic colon examinations: a review of 38 recent cases.

OBJECTIVE: Our purposes were to determine the causes of malpractice claims against radiologists performing contrast examinations of the colon and to design strategies to reduce litigation and diminish patient morbidity. MATERIALS AND METHODS: Reports of malpractice claims were collected from legal journals and databases between 1985 and 1994. For this period, 38 plaintiffs raised 52 allegations of malpractice that involved radiologists performing barium or Hypaque (meglumine diatrizoate; Winthrop Pharmaceuticals, New York, NY) colon examinations. For the 38 cases, 18 plaintiffs for decedents alleged that failure to diagnose colorectal cancer by barium enema examination caused delay in treatment and the patient's death. Eighteen plaintiffs alleged that improper performance of barium (17 cases) or meglumine diatrizoate (one case) colon examinations caused perforation of the colon, resulting in significant morbidity (15 cases) or death (three cases). Miscellaneous causes for malpractice claims were recorded in two cases. RESULTS: In 18 cases of failure to diagnose colorectal cancer, the initial radiographs were interpreted as follows: normal findings in 14 cases, diverticulosis in one case, and spastic bowel in two cases; in the remaining case, colon cancer was missed because of nonopacification of the cecum. In retrospect, 17 of 18 colorectal cancers were visualized. The delay in the diagnosis of colorectal cancer ranged from 5 to 72 months. Missed colorectal cancers occurred in the cecum (two cases), transverse colon (two cases), rectosigmoid area (nine cases), or unspecified area (five cases). In 18 cases of colon perforation, the site was the cecum (one case), transverse colon (one case), extraperitoneal rectum (seven cases), rectosigmoid area (one case), colostomy stoma (two cases), or unspecified area (six cases). One patient experienced anaphylactic shock that required hospitalization. One underwent unnecessary surgery because barium enema films showing colon cancer were mislabeled with her name. CONCLUSION: On the basis of our analyses of malpractice claims, we suggest strategies to prevent medicolegal litigation. Strategies include communicating with the patient about the type and indications of the barium enema examination, performing digital rectal examinations on all patients to detect distal rectal lesions or strictures, recognizing colon perforation, and obtaining immediate surgical consultation if colon perforation occurs. The number of missed colon cancers may be reduced by reading twice or reviewing at a later time all barium enema examinations.

Adult↗

Preterm labor, placental abruption, and premature rupture of membranes in relation to maternal violence or verbal abuse.

OBJECTIVE: The prevalence of preterm labor (PTL) in prenatal populations has been estimated to be from 6.9 to 10.0%. It has been suggested that violence during pregnancy may be associated with an increase in antenatal complications. The hypothesis is that physical violence and verbal abuse in pregnancy lead to increased risk of PTL. METHODS: A cohort of 636 women attending the Adult Obstetrical Clinic for their first prenatal visit, between December 1989 and September 1990, were approached; 567 women enlisted as study participants. Study participants were interviewed 3 times during the course of their prenatal care, and 401 participants successfully completed their third prenatal interviews. Violence data were obtained during the third interview. Obstetrical and neonatal outcome data were obtained by abstracting the maternal and neonatal medical records. RESULTS: When stratified by levels of violence, women who experienced moderate or severe violence had incidences of PTL of 15.4 and 17.2%, respectively. Chi-square test for homogeneity revealed a significant difference among these groups. CONCLUSIONS: In our cohort of women, serious acts of verbal abuse and physical violence occurred with significant frequency. PTL was strongly correlated with increasing acts of violence with 4.1 times greater risk of PTL in women who experienced severe violence as compared to those who experienced no maternal abuse.

Abruptio Placentae↗