Branching fraction and photon energy spectrum for b --> s gamma

We have measured the branching fraction and photon energy spectrum for the radiative penguin process b-->s gamma. We find Beta(b-->s gamma) = (3.21+/-0.43+/-0.27(+0.18)(-0.10))x10(-4), where the errors are statistical, systematic, and from theory corrections. We obtain first and second moments of the photon energy spectrum above 2.0 GeV, <E( gamma)> = 2.346+/-0.032+/-0.011 GeV, and <E(2)(gamma)>-<E(gamma)>(2) = 0.0226+/-0.0066+/-0.0020 GeV(2), where the errors are statistical and systematic. From the first moment, we obtain (in the modified minimal subtraction renormalization scheme, to order 1/M(3)(B) and beta(0)alpha(2)(s)) the heavy quark effective theory parameter Lambda = 0.35+/-0.08+/-0.10 GeV.

First measurement of gamma(D*(+))

We present the first measurement of the D*(+) width using 9/fb of e(+)e(-) data collected near the Upsilon(4S) resonance by the CLEO II.V detector. Our method uses advanced tracking techniques and a reconstruction method that takes advantage of the small vertical size of the Cornell Electron-positron Storage Ring beam spot to measure the energy release distribution from the D*(+)-->D(0)pi(+) decay. We find gamma(D*(+)) = 96+/-4 (stat)+/-22 (syst) keV. We also measure the energy release in the decay and compute Delta m identical with m(D*(+))-m(D(0)) = 145.412+/-0.002 (stat)+/-0.012 (syst) MeV/c(2).

Search for the decay upsilon(1S) --> gammaeta(')

We report on a search for the radiative decay Upsilon(1S)-->gammaeta(') in 61.3 pb(-1) of data taken with the CLEO II detector at the Cornell Electron Storage Ring. Three decay chains were investigated, all involving eta(')-->pi(+)pi(-)eta, followed by eta-->gammagamma, eta-->pi(0)pi(0)pi(0), or eta-->pi(+)pi(-)pi(0). We find no candidate events in any of the three cases and set a combined upper limit of 1.6x10(-5) at 90% C.L., significantly smaller than the previous limit. We compare our result to other radiative Upsilon decays, to radiative J/psi decays, and to theoretical predictions.

Primary hyperoxaluria type 1: improved outcome with timely liver transplantation: a single-center report of 36 children

BACKGROUND

The appropriate use of liver transplantation in children with type-1 primary hyperoxaluria (PH-1) is not well established. We reviewed our experience with 36 children with PH-1, including 12 who underwent liver transplantation.

PATIENTS AND METHODS

From 1989-1998, 36 children from 10 families in northern Israel were diagnosed with PH-1. Eight children presented with renal failure; seven of these eight had the severe infantile form of the disease. One child was treated with kidney transplantation alone. Combined liver-kidney transplantation has been performed in nine children and preemptive liver transplantation in three children. A review of the patients' charts for the following parameters was performed: age, clinical signs, and renal sonographic findings at diagnosis, age at onset of dialysis, and current status. Type of transplant, pre- and posttransplant urine oxalate excretion, current renal function, survival, and complications were recorded in liver recipients.

RESULTS

Of the 23 nontransplanted children, 9 died of complications related to severe systemic oxalosis and 14 are alive (mean follow-up, 7.4 years), including 2 who are candidates for transplantation. The child who underwent only kidney transplantation died of unrelated causes. Of the 12 liver recipients, 2 died within the first 3 months posttransplant and another child underwent retransplantation due to hepatic arterial thrombosis. At intervals after transplant ranging from 6-54 months, 10 recipients are alive (7 of the 9 recipients of combined liver-kidney transplants and all 3 recipients of preemptive liver transplants). Mean GFR in the 10 survivors is 77 ml/min/m2. In 9 of these 10, daily urinary oxalate excretion normalized. Renal function has improved (mean GFR 86 vs. 58 ml/min/m2) but renal oxalate deposits remain in the three recipients of isolated liver grafts.

CONCLUSIONS

Our decade-long experience with children with PH-1 supports strategies for early diagnosis and timely liver transplantation. Preemptive isolated liver transplantation should be considered in children who develop the disease during infancy or in those with slowly progressive disease when significant symptoms develop. Combined liver-kidney transplantation is suggested for children with end-stage renal disease.

Rate measurement of D(0)-->K+pi(-)pi(0) and constraints on D(0) -- D(0) mixing

We present an observation and time-integrated rate measurement of the decay D(0)-->K(+)pi(-)pi(0) produced in 9 fb(-1) of e(+)e(-) collisions near the Upsilon(4S) resonance. The signal is inconsistent with an upward fluctuation of the background by 4.9 standard deviations. We measured the time-integrated rate of D(0)-->K(+)pi(-)pi(0) normalized to the rate of D(0)-->K(+)pi(-)pi(0) to be 0.0043(+0.0011)(-0.0010) (stat)+/-0.0007 (syst). This decay can be produced by doubly Cabibbo-suppressed decays or by the D(0) evolving into a D(0) through mixing, followed by a Cabibbo-favored decay to K(+)pi(-)pi(0). We also found the CP asymmetry A = (9(+25)(-22))% be consistent with zero.

Experimental investigation of the two-photon widths of the chi(c0) and the chi(c2) mesons

Using 12.7 fb(-1) of data collected with the CLEO detector at CESR, we observed two-photon production of the cc states chi(c0) and chi(c2) in their decay to pi(+)pi(-)pi(+)pi(-). We measured gamma(gammagamma)(chi(c))xB(chi(c)-->pi(+)pi(-)pi(+)pi(-)) to be 75+/-13(stat)+/-8(syst) eV for the chi(c0) and 6.4+/-1.8(stat)+/-0.8(syst) eV for the chi(c2), implying gamma(gammagamma)(chi(c0)) = 3.76+/-0.65(stat)+/-0.41(syst)+/-1.69(br) keV and gamma(gammagamma)(chi(c2)) = 0.53+/-0.15(stat)+/-0.06(syst)+/-0.22(br) keV. Also, cancellation of dominant experimental and theoretical uncertainties permits a precise comparison of gamma(gammagamma)(chi(c0))/gamma(gammagamma)(chi(c2)), evaluated to be 7.4+/-2.4(stat)+/-0.5(syst)+/-0.9(br), with QCD-based predictions.

Bounds on the CP asymmetry in b --> sgamma decays

We have measured the CP asymmetry A(CP) identical with[gamma(b-->sgamma)-gammab-->sgamma)]/[gamma(b-->sgamma)+gamma(b-->sgamma)] to be A(CP) = (-0.079+/-0.108+/-0.022) (1.0+/-0.030), implying that, at 90% confidence level, A(CP) lies between -0.27 and +0.10. These limits rule out some extreme non-standard-model predictions, but are consistent with most, as well as with the standard model.

Inferior vena cava diameter: a useful method for estimation of fluid status in children on haemodialysis

BACKGROUND

An accurate assessment of fluid status in haemodialysis patients presents a significant challenge especially in growing children. Clinical parameters of hydration are not always reliable, and invasive methods such as measurement of central venous pressure cannot be used routinely. We evaluated the usefulness of inferior vena cava diameter (IVCD) measured by echocardiography in the estimation of hydration in children on haemodialysis.

METHODS

Fifteen haemodialysis patients (mean age 14 years) were evaluated. Clinical assessment included patients' symptoms, weight, blood pressure, heart rate, presence of oedema and vascular congestion, before and after dialysis session. Dry weight was assessed based on the above parameters. Fifty-two echocardiographic studies immediately prior and 30-60 min following dialysis were performed. The anteroposterior IVCD was measured 1.5 cm below the diaphragm in the hepatic segment in supine position during normal inspiration and expiration. IVCD was expressed per body surface area.

RESULTS

Following haemodialysis mean IVCD (average of expiration and inspiration) decreased from 1.12+/-0.38 to 0.75+/-0.26 cm/m(2) (P<0.0001). Changes in IVCD were significantly correlated with alterations in body weight following dialysis (P<0.0001). The collapse index (per cent of change in IVCD in expiration vs inspiration) increased significantly after dialysis (P=0.035). IVCD clearly reflected alterations in fluid status. It did not vary significantly with changes in dry weight in a given patient.

CONCLUSIONS

Our findings support the applicability of VCD measurement in the estimation of hydration status in paediatric haemodialysis patients. The combination of clinical parameters and measurement of IVCD may enable more accurate evaluation of hydration of children on haemodialysis.

Bounds on the CP asymmetry in like-sign dileptons from B(0)B*(0) meson decays

We have measured the charge asymmetry in like-sign dilepton yields from B(0)B*(0) meson decays using the CLEO detector at the Cornell Electron Storage Ring. We find a(0)(ll) identical with[N(l(+)l(+))-N(l(-)l(-))]/[N(l(+)l(+))+N(l(-)l(-))] = +0.013+/-0.050+/-0.005. We combine this result with a previous, independent measurement and obtain Re(epsilon(B))/(1+ the absolute value of epsilon(B)(2)) = +0.0035+/-0.0103+/-0.0015 (uncertainties are statistical and systematic, respectively) for the CP impurity parameter, epsilon(B).

Study of tau decays to six pions and a neutrino

The tau decays to six-pion final states have been studied with the CLEO detector at the Cornell Electron Storage Ring. The measured branching fractions are B(tau(-)-->2pi(-)pi(+)3pi(0)nu(tau)) = (2.2+/-0.3+/-0.4)x10(-4) and B(tau(-)-->3pi(-)2pi(+)pi(0)nu(tau)) = (1.7+/-0.2+/-0.2)x10(-4). A search for substructure in these decays shows that they are saturated by intermediate states with eta or omega mesons. We present the first observation of the decay tau(-)-->2pi(-)pi(+)omega(nu)tau and the branching fraction is measured to be (1.2+/-0.2+/-0.1)x10(-4). The measured branching fractions are in good agreement with the isospin expectations but somewhat below the conserved-vector-current predictions.

Observation of new states decaying into Lambda+(c)pi(-)pi(+)

Using 13.7 fb(-1) of data recorded by the CLEO detector at the Cornell Electron Storage Ring, we investigate the spectrum of charmed baryons which decay into Lambda+(c)pi(-)pi(+) and are more massive than the Lambda+(c)(2625) baryon. We find evidence for two new states: one is broad and has an invariant mass roughly 480 MeV above that of the Lambda+(c) baryon; the other is narrow with an invariant mass of 596+/-1+/-2 MeV above the Lambda+(c) mass.

Evidence of New States Decaying into Xi(*)(c)pi

Using 13.7 fb(-1) of data recorded by the CLEO detector at Cornell Electron Storage Ring, we report evidence of two new charmed baryons: one decaying into Xi(0')(c)pi(+) with the subsequent decay Xi(0')(c)-->Xi(0)(c)gamma, and its isospin partner decaying into Xi(+')(c)pi(-) followed by Xi(+')(c)-->Xi(+)(c)gamma. We measure the following mass differences for the two states: M(Xi(0)(c)gammapi(+))-M(Xi(0)(c)) = 318.2+/-1.3+/-2.9 MeV and M(Xi(+)(c)gammapi(-))-M(Xi(+)(c)) = 324.0+/-1.3+/-3.0 MeV. We interpret these new states as the J(P) = 1 / 2(-) Xi(c1) particles, the charmed-strange analogs of the Lambda(+)(c1)(2593).

Observation of B --> phiK and B --> phiK*

We have studied two-body charmless hadronic decays of B mesons into the final states straight phiK and phiK(*). Using 9.7 million B&Bmacr; pairs collected with the CLEO II detector, we observe the decays B- --> phiK- and B0--> phiK(*0) with the following branching fractions: B(B--->phiK-) = (5.5(+2.1)(-1.8)+/-0.6)x10(-6) and B(B0--> phiK(*0)) = (11.5(+4.5+1.8)(-3.7-1.7))x10(-6). We also see evidence for the decays B0-->phiK0 and B---> phiK(*-). However, since the statistical significance is not overwhelming for these modes, we determine upper limits of <12.3x10(-6) and <22.5x10(-6) ( 90% confidence level), respectively.

Observation of the Omega(0)(c) Charmed Baryon at CLEO

The CLEO experiment at the CESR collider has used 13.7 fb(-1) of data to search for the production of the Omega(0)(c) (css ground state) in e(+)e(-) collisions at square root of (s) approximately 10.6 GeV. The modes used to study the Omega(0)(c) are Omega(-)pi(+), Omega(-)pi(+)pi(0), Xi-K-pi(+)pi(+), Xi0K-pi(+), and Omega(-)pi(+)pi(+)pi(-). We observe a signal of 40.4+/-9.0(stat) events at a mass of 2694.6+/-2.6(stat)+/-1.9(syst) MeV/c(2), for all modes combined.

Search for B --> tau(nu) and B --> K(nu)nu

We report results of a search for B-->tau(nu) in a sample of 9.7 x 10(6) charged B meson decays. We exclusively reconstruct the companion B decay to suppress background. We set an upper limit on the branching fraction B(B-->tau(nu))<8.4 x 10(-4) at 90% confidence level. We also establish B(B+/--->K+/-nu(nu))<2.4 x 10(-4) at 90% confidence level.

Measurement of the relative branching fraction of upsilon(4S) to charged and neutral B-meson pairs

We analyze 9.7x10(6) B_B pairs recorded with the CLEO detector to determine the production ratio of charged to neutral B-meson pairs produced at the Upsilon(4S) resonance. We measure the rates for B0-->J/psiK((*)0) and B+-->J/psiK((*)+) decays and use the world-average B-meson lifetime ratio to extract the relative widths f(+-) / f(00) = gamma(Upsilon(4S)-->B+B-) / gamma(Upsilon(4S)-->B0 B-0)) = 1.04+/-0.07(stat)+/-0.04(syst). With the assumption that f(+-)+f(00) = 1, we obtain f(00) = 0.49+/-0.02(stat)+/-0.01(syst) and f(+-) = 0.51+/-0.02(stat)+/-0.01(syst). This production ratio and its uncertainty apply to all exclusive B-meson branching fractions measured at the Upsilon(4S) resonance.

First observation of the decays B(0) --> D(*-)p_p pi+ and B(0) --> D(*-)p_n

We report the first observation of exclusive decays of the type B-->D(*)N_NX, where N is a nucleon. Using a sample of 9.7x10(6)B_B pairs collected with the CLEO detector operating at the Cornell Electron Storage Ring, we measure the branching fractions B(B0-->D(*-)p_p pi(+)) = (6.5(+1.3)(-1.2)+/-1.0)x10(-4) and B(B0-->D(*-)p_n) = (14.5(+3.4)(-3.0)+/-2.7)x10(-4). Antineutrons are identified by their annihilation in the CsI electromagnetic calorimeter.

Measurement of the lambda(+)(c) lifetime

The Lambda+c lifetime is measured using 9.0 fb(-1) of e+e- annihilation data collected on or just below the Upsilon(4S) resonance with the CLEO II.V detector at CESR. Using an unbinned maximum likelihood fit, the Lambda+c lifetime is measured to be 179.6+/-6.9(stat)+/-4.4(syst) fs. The precision of this colliding beam measurement is comparable to other measurements, which are based on fixed-target experiments, with different systematic uncertainties.

First observation of the sigma(*+)(c) baryon and a new measurement of the sigma(*+)(c) mass

Using data recorded with the CLEO II and CLEO II.V detector configurations at the Cornell Electron Storage Rings, we report the first observation and mass measurement of the Sigma(*+)(c) charmed baryon, and an updated measurement of the mass of the Sigma(+)(c) baryon. We find M(Sigma(*+)(c))-M(Lambda(+)(c)) = (231.0+/-1.1+/-2.0) MeV, and M(Sigma(+)(c))-M(Lambda(+)(c)) = (166.4+/-0.2+/-0.3) MeV, where the errors are statistical and systematic, respectively.

Study of B Decays to Charmonium States: B-->eta(c)K and B --> chi(c0)K

In a sample of 9.66x10(6)B&Bmacr; pairs collected with the CLEO detector we make the first observation of B decays to an eta(c) and a kaon. We measure branching fractions B(B+-->eta(c)K+) = (0.69(+0.26)(-0.21)+/-0.08+/-0.20)x10(-3) and B(B degrees -->eta(c)K degrees ) = (1.09(+0.55)(-0.42)+/-0.12+/-0.31)x10(-3), where the first error is statistical, the second is systematic, and the third is from the eta(c) branching fraction uncertainty. From these we extract the eta(c) decay constant in the factorization approximation, f(eta(c)) = 335+/-75 MeV. We also search for B decays to a chi(c0) and a kaon. No evidence for a signal is found and we set 90% C.L. upper limits: B(B+-->chi(c0)K+)<4.8x10(-4) and B(B degrees -->chi(c0)K degrees )<5.0x10(-4).

Human tissue research in the genomic era of medicine: balancing individual and societal interests

Advances in DNA sequencing technology and in our understanding of the human genome are ushering in a new era of genomic medicine, one with dramatic potential to not only benefit society through research involving human tissue, but also to cause economic or psychosocial harms to tissue donors and their families. This delicate situation requires that the needs of tissue donors be carefully considered and balanced with those of the medical research community, especially on issues concerning confidentiality, consent, and compensation. We analyzed the tensions between tissue donors and researchers over the research use of human tissue. We also reviewed several approaches, including the establishment of tissue-trustee infrastructures at academic medical centers, aimed at achieving a more equitable balance between individual donor protection and societal benefits derived from tissue-based research. Arch Intern Med. 2000;160:3377-3384.

Measurements of the mass, total width, and two-photon partial width of the eta(c) meson

Using 13.4 fb(-1) of data collected with the CLEO detector at the Cornell Electron Storage Ring, we have observed 300 events for the two-photon production of ground-state pseudoscalar charmonium in the decay eta(c)-->K(0)(S)K-/+pi(+/-). We have measured the eta(c) mass to be [2980.4+/-2.3 (stat)+/-0.6 (syst)] MeV and its full width as [27.0+/-5.8 (stat)+/-1.4 (syst)] MeV. We have determined the two-photon partial width of the eta(c) meson to be [7.6+/-0.8 (stat)+/-0.4 (syst)+/-2.3 (br)] keV, with the last uncertainty associated with the decay branching fraction.

Study of charmless hadronic B meson decays to pseudoscalar-vector final states

We report results of searches for charmless hadronic B meson decays to pseudoscalar( pi(+/-), K+/-, pi(0), or K(0)(S))-vector( rho, K(*), or omega) final states. By using 9.7x10(6) BB pairs collected with the CLEO detector, we report the first observation of B(-)--->pi(-)rho(0), B(0)-->pi(+/-)rho(-/+), and B(-)-->pi(-)omega, which are expected to be dominated by hadronic b-->u transitions. The measured branching fractions are (10.4(+3.3)(-3.4)+/-2.1)x10(-6), (27.6(+8.4)(-7.4)+/-4.2)x10(-6), and (11.3(+3.3)(-2.9)+/-1. 4)x10(-6), respectively. Branching fraction upper limits are set for all of the other decay modes investigated.

Impact of Antibiotic Resistance on the Treatment of Gram-negative Sepsis

Resistance among gram-negative organisms has greatly complicated the care of the septic patient. An understanding of the likely source of infection, the epidemiologic risk of the patient being exposed to an antibiotic-resistant organism, and the specific vulnerabilities of the host are essential to the proper selection of empiric antimicrobial therapy. In this report, we discuss the epidemiology, antibiotic resistance mechanisms, microbiology, treatment strategies, and diagnostic and therapeutic innovations in the approach to the septic patient.

Study of exclusive radiative B meson decays

We have studied exclusive, radiative B meson decays to charmless mesons in 9.7x10(6) B&Bmacr; decays accumulated with the CLEO detector. We measure B(B0-->K(*0)(892)gamma) = (4.55(+0.72)(-0. 68)+/-0.34)x10(-5) and B(B+-->K(*+)(892)gamma) = (3.76(+0.89)(-0. 83)+/-0.28)x10(-5). We have searched for CP asymmetry in B-->K(*)(892)gamma decays and measure A(CP) = +0.08+/-0.13+/-0.03. We report the first observation of B-->K(*)(2)(1430)gamma decays with a branching fraction of (1.66(+0.59)(-0.53)+/-0.13)x10(-5). No evidence for the decays B-->rhogamma and B0-->omegagamma is found and we limit B(B-->(rho/omega)gamma)/B(B-->K(*)(892)gamma)<0.32 at 90% C.L.