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Renu Sharma

Publications and source records attributed to Renu Sharma.

18 recordsLinked to original sources
PubMed2006

Synthesis of 1D {Cu6(mu3-SC3H6N2)4(mu-SC3H6N2)2(mu-I)2I4}n and 3D {Cu2(mu-SC3H6N2)2(mu-SCN)2}n polymers with 1,3-imidazolidine-2-thione: bond isomerism in polymers.

The reaction of copper(I) iodide with 1, 3-imidazolidine-2-thione (SC3H6N2) in a 1:2 molar ratio (M/L) has formed unusual 1D polymers, {Cu6(mu3-SC3H6N2)4(mu-SC3H6N2)2(mu-I)2I4}n (1) and {Cu6(mu3-SC3H6N2)2(mu-SC3H6N2)4(mu-I)4I2}n (1a). A similar reaction with copper(I) bromide has formed a polymer {Cu6(mu3-SC3H6N2)2(mu-SC3H6N2)4(mu-Br)4Br2}n (3a), similar to 1a, along with a dimer, {Cu2(mu-SC3H6N2)2(eta1-SC3H6N2)2Br2} (3). Copper(I) chloride behaved differently, and only an unsymmetrical dimer, {Cu2(mu-SC3H6N2)(eta1-SC3H6N2)3Cl2} (4), was formed. Finally, reactions of copper(I) thiocyanate in 1:1 or 1:2 molar ratios yielded a 3D polymer, {Cu2(mu-SC3H6N2)2(mu-SCN)2}n (2). Crystal data: 1, C9H18Cu3I3N6S3, triclinic, P, a = 9.6646(11) A, b = 10.5520(13) A, c = 12.6177(15) A, alpha = 107.239(2) degrees , beta = 99.844(2) degrees , gamma = 113.682(2) degrees , V = 1061.8(2) A(3), Z = 2, R = 0.0333; 2, C(4)H(6)CuN(3)S(2), monoclinic, P2(1)/c, a = 7.864(3) A, b = 14.328(6) A, c = 6.737(2) A, beta = 100.07(3) degrees , V = 747.4(5), Z = 4, R = 0.0363; 3, C12H24Br2Cu2N8S4, monoclinic, C2/c, a = 19.420(7) A, b = 7.686(3) A, c = 16.706(6) A, beta = 115.844(6) degrees , V = 2244.1(14) A(3), Z = 4, R = 0.0228; 4, C12H24Cl2Cu2N8S4, monoclinic, P2(1)/c, a = 7.4500(6) A, b = 18.4965(15) A, c = 16.2131(14) A, beta = 95.036(2) degrees , V = 2225.5(3) A(3), Z = 4, R = 0.0392. The 3D polymer 2 exhibits 20-membered metallacyclic rings in its structure, while synthesis of linear polymers, 1 and 1a, represents an unusual example of I (1a)-S (1) bond isomerism.

Journal Article↗
PubMed2006

Nanoscale heterogeneity in ceria zirconia with low-temperature redox properties.

We have investigated nanoscale compositional and structural variations in Ce(0.5)Zr(0.5)O(2) samples with different redox properties. Different samples were prepared using a spray freezing technique, and the synthesis conditions were varied to yield materials with reduction temperatures in the range of 400-750 degrees C. X-ray diffraction and thermal gravimetric analysis were used to characterize the average structures and redox properties of these materials. The nanoscale structural and compositional variations in individual nanoparticles of high activity were determined with atomic-scale electron imaging and nanometer-resolution electron energy loss spectroscopy. During the early stage of particle formation, the crystallization process is initiated via the nucleation of ceria-rich nanodomains. This results in the formation of high-surface-area materials that exhibit nanoscale compositional heterogeneity consisting of Ce-rich cores surrounded by Zr-rich shells. The effect of high-temperature redox cycling on the nanoscale structure, composition, and low-temperature redox properties was also determined. Our analysis suggests that our most active material exhibits significant compositional and structural heterogeneity at the nanometer level.

Journal Article↗
PubMed2006

Coming full circle: an evidence-based definition of the timing and type of surgical management of very low-birth-weight (<1000 g) infants with signs of acute intestinal perforation.

OBJECTIVE: Gut disruption in very low birth weight follows 1 of 3 clinical pathways: isolated perforation with sudden free air, metabolic derangement (MD) complicated by appearance of free air, or progressive metabolic deterioration without evidence of free air. To refine evidence-based indications for peritoneal drainage (PD) vs laparotomy (LAP), we hypothesized that MD acuity is the determinant of outcome and should dictate choice of PD or LAP. METHODS: Very low-birth-weight infants referred for surgical care because of free intraperitoneal air or MD associated with signs of enteritis were evaluated by univariate or multivariate logistic regression to investigate the effect on mortality of MD and initial surgical care (LAP vs PD). Metabolic derangement was scaled by assigning 1 point each for thrombocytopenia, metabolic acidosis, neutropenia, left shift of segmented neutrophils, hyponatremia, bacteremia, or hypotension. Laparotomy and PD were stratified by MD acuity, and odds of mortality were calculated for each surgical option. RESULTS: From October 1991 to December 2003, 65 very low-birth-weight infants with suspected gut disruption were referred for surgical care. Peritoneal drainage and LAP infants had similar birth weight and gastrointestinal age, neither of which predicted mortality. Despite a higher incidence of isolated perforation with sudden free air in PD infants, the incidence of MD and overall mortality were similar for PD and LAP. Multivariate logistic regression demonstrated MD to be the best predictor of mortality (odds ratio [OR], 4.76; confidence interval [CI], 1.41-16.13, P = .012), which significantly increased with interval between diagnosis to surgical intervention (P < .05). Infants with MD receiving PD had a 4-fold increase in mortality (OR, 4.43; CI, 1.37-14.29; P = .0126). Conversely, those without MD and sudden free air who underwent LAP had a 3-fold increase in mortality (OR, 2.915; CI, 1.107-7.692; P = .03.) Of 5, 3 failed PD were "rescued" by LAP. CONCLUSIONS: The dramatic difference in mortality odds based on surgical option in the presence of MD defines the critical importance of a thorough assessment of physiological status to exclude MD. Absence of MD warrants consideration for PD, especially for sudden intraperitoneal free air. Overwhelming MD may limit options to PD; however, salvage of 3 of 5 infants with failed PD demonstrates the value of LAP, whenever possible, for infants with MD.

Acute Disease↗
PubMed2005

Neonatal gut injury and infection rate: impact of surgical debridement on outcome.

Infectious burden of gut injury (G-INJ) associated with necrotizing enterocolitis (NEC) or with spontaneous intestinal perforation (SIP) in neonates has not been ascertained. We sought to test the hypotheses that: (1) infants with G-INJ develop higher number of infections including non-concurrent infections than infants without G-INJ in a neonatal intensive care unit (NICU); (2) surgical debridement (DEB) of infants with severe G-INJ is associated with lower infectious morbidity and mortality. All infants admitted to the regional NICU from October 1991 to February 2003 were included in this prospective prevalence investigation of G-INJ and infections. Non-viable (<23 week gestational age) infants, infants with congenital anomalies, and those who developed NEC after SIP were excluded. Standard definitions of National Centers for Disease Control and Prevention were used for different categories of infections. Episodes of infections were classified as concurrent or non-concurrent (post G-INJ) based upon their timing in association with G-INJ. Infants with G-INJ associated with Bell stage II or higher NEC or with SIP were further stratified by DEB into two subgroups. A previously described 7-point clinical score was used to divide G-INJ into mild (0-2), moderate (3-5), and severe (6-7) categories. Surgical outcomes were determined by using chi(2) and logistic regression analyses. Data are expressed as mean +/- SD or as odds ratio (OR) with 95% confidence intervals (CI); P < 0.05 was considered significant. Of all 5,481 infants, 954 (17.4%) developed 1,734 episodes of infections. Prevalence of G-INJ was 4% (n = 222); of these, 33% (n = 73) underwent DEB. Infants with G-INJ had lower mean birth weight (1,414+/-766 vs. 2,153+/-104 g; P < 0.0001) and lower mean gestational age (29.6+/-4.2 vs. 32.9+/-4.8 weeks; P < 0.0001) than their peers (n = 5,259). Controlling for birth weight and gestational age, odds for non-concurrent blood stream infections (BSIs) in G-INJ infants were higher (OR 13.98, CI 10.289-19.01, P < 0.0001) than the remaining population without G-INJ. Forty-four percent of all episodes of fungemia, 32% of all episodes of BSIs occurred in G-INJ infants (P < 0.0001). Within the G-INJ group, there were no demographic differences between the DEB and non-DEB infants. Controlling for severity of G-INJ, odds for non-concurrent BSIs (OR 3.45, CI 1.04-11.36, P < 0.05) and for mortality (OR 3.35, CI 1-10, P < 0.05) among non-DEB infants were higher than in DEB infants. Infants with G-INJ suffered from a disproportionate number of all blood-stream infections in our intensive care nursery. Infants with severe G-INJ whose management includes DEB are more likely to survive and to incur less infectious morbidity.

Debridement↗
PubMed2005

In situ observation of the growth mechanisms of carbon nanotubes under diverse reaction conditions.

We report in situ environmental transmission electron microscope observations of the nucleation and growth of multi-wall and single-wall carbon nanotubes formed by the catalytic decomposition of acetylene (C2H2) on Ni/SiO2 catalyst. The growth rate, structure and morphology of the carbon nanotubes formed depended upon reaction temperature and pressure. Under 20-100 mTorr of gas pressures at 480 degrees C, serpentine-shaped or zigzag, multi-wall carbon nanotubes grew at an average rate of 35-40 nm sec(-1). At pressures <10 mTorr at the same temperature, straight single-wall carbon nanotubes with nearly uniform diameters (approximately 3.5 nm) formed at average growth rates of 6-9 nm sec(-1). The growth of both straight and serpentine carbon nanotubes tends to proceed at non-uniform rates, with frequent pauses followed by growth spurts. The nanotubes frequently contained sharp bends that turned the nanotube axis by approximately 60 degrees and approximately 120 degrees. We conjecture that the bends are related to the change in growth direction that is dictated by the crystallographic orientation of the catalyst particle. The rotations of the nanometer-sized catalyst particle may be caused by transient melting-recrystallization events caused by local thermal variations. The nanotube attempts to follow the preferred growth direction, while simultaneously attempting to maintain a seamless 3-coordinated graphene wall. This latter condition is most easily satisfied by the introduction of pentagon-heptagon defect pairs dissociated to the opposite sides of the nanotube creating the 60 degree bend.

Journal Article↗
PubMed2005

Self-assembled structure of nanoparticles at a liquid-liquid interface.

Pickering emulsions are used as a template to investigate the multiphase interactions and self-assembled structure of nanoparticles at a trichloroethylene-water interface. The dodecanethiol-capped silver nanoparticles of 1-5 nm form randomly distributed multilayers at the liquid/liquid interface, with an interparticle distance varying from close contact to approximately 25 nm. This report offers the first direct observation of nanoparticles in a liquid medium using the environmental transmission electron microscope, as well as the first work revealing the detailed self-assembled structure of nanoparticles at a liquid/liquid interface when the size of the nanoparticles is comparable to the molecular dimension of the liquids.

Emulsions↗
PubMed2005

Versatility of heterocyclic thioamides in the construction of a trinuclear cluster [Cu3I3(dppe)3 (SC5H4NH)] and Cu(I) linear polymers {Cu6(SC5H4NH)6I6}n x 2nCH3CN and {Cu(I)6 (SC3H6N2)6X6}n (X = Br, I).

Reaction of copper(I) iodide with pyridine-2-thione (2-SC5H4NH) and 1,2-bis(diphenylphosphino)ethane (dppe) in a CH3CN-CHCl3 mixture yielded a triangular cluster, [Cu3I3(mu2-P,P-dppe)3 (eta1-SC5H4NH)], 1. Similar reaction with 2-SC5H4NH and a series of diphosphanes, Ph2P-X-Ph2P {X = -CH2- (dppm), -(CH2)3- (dppp), -(CH2)4- (dppb), -CH=CH- (dppen)}, gave a novel iodo-bridged hexanuclear Cu(I) linear polymer,{Cu6(mu3-SC5H4NH)4 (mu2-SC5H4NH)2 (I4)(mu-I)2-}n x 2nCH3CN, 2. Reactions of copper(I) iodide/copper(I) bromide with 1,3-imidazolidine-2-thione (SC3H6N2) in a CH3CN-CHCl3 mixture yielded hexanuclear Cu(I) linear chain polymers, [{Cu6(mu3-SC3H6N2)2 (mu2-SC3H6N2)4X2 (mu-X)4}n] (X = Br, 4; I, 5). In compound 1, two iodide atoms and one dppe form the dinuclear Cu(mu2-I)2 (mu2-dppe)Cu core, and two dppe ligands bridge this core with the third Cu(I) center coordinated to 2-SC5H4NH via the S atom. The chain polymer 2 has a centrosymmetric hexanuclear central core, Cu6S6I4 (mu-I)2--, formed by dimerization of six-membered trinuclear motifs, Cu3(mu2-SC3H6N2)3I3 via (mu3-S) bonding modes of the thione ligand, and has four terminal and two bridging iodine atoms in trans-orientations. Linear chains are separated by the nonbonded acetonitrile molecules. In 4 and 5, three copper(I) bromide or copper(I) iodide moieties and three SC3H6N2 ligands combined via bridging S donor atoms to form the six-membered trinuclear Cu3(mu2-SC3H6N2)3I3 cores which polymerized via S and X atoms in a side-on fashion to form linear chain polymers, [{Cu6(mu3-SC3H6N2)2 (mu2-SC3H6N2)4X2(mu-X)4}n]. The (mu3-S) modes of bonding of neutral heterocyclic thioamides are first examples, as are trinuclear cluster and linear polymers rare examples in copper chemistry.

Journal Article↗
PubMed2005

A topological model of biofeedback based on catecholamine interactions.

BACKGROUND: The present paper describes a topological model of biofeedback. This model incorporates input from a sensory organ and a transduction phase mediated through catecholamine production in the feedback path. The transduction phase comprises both conservative and dissipative systems, from which the appropriate output is combined in a closed loop. RESULTS: The model has been simulated in MATLAB 6.0 R12 in order to facilitate a comprehensive understanding of the complex biofeedback phenomena concomitant with the transduction phases associated with migraine and with psychosomatic diseases involving digestive disorders. CONCLUSION: The complexity of the biological system influences the transduction phase and nature of the system response, which is consequent on the activation of smooth muscles by sympathetic and parasympathetic stimulation.

Aging↗
PubMed2005

Portal venous gas and surgical outcome of neonatal necrotizing enterocolitis.

PURPOSE: The prognostic significance of portal venous gas (PVG) in neonatal necrotizing enterocolitis (NEC) for operative intervention (OP), neonatal complications, and mortality remains uncertain. The authors designed a long-term prospective study to describe the natural history of PVG related to these outcomes and to test the hypothesis that PVG does not mandate OP. METHODS: All infants admitted to a single center between October 1991 and February 2003 were evaluated weekly to identify all cases of NEC (defined as Bell stage II or higher). Demographic, radiological, surgical, and outcome data were abstracted prospectively. Radiographic studies were performed at the onset of illness and at subsequent 6- to 8-hour intervals or as clinically indicated. A single pediatric radiologist reviewed all radiographs. Values are expressed as mean +/- SD. Odds ratios and relative risk ratios are reported with 95% CIs. The level of significance was P < or = .05. RESULTS: After the exclusion of 24 infants with lethal diseases, major congenital or chromosomal anomalies, or recurrent episodes of NEC, 194 of 5891 infants developed NEC. The overall incidence of NEC was 3.7%. In 194 infants with NEC, the incidence of PVG was 33% (n = 64). Gestational age (30.8 +/- 4 vs 29.3 +/- 4.2 weeks; P = .02) but not birth weight (1609 +/- 761 vs 1434 +/- 810 g; P = NS) was greater in infants with PVG compared with infants without PVG (n = 130). Sixty-six (34%) infants with NEC underwent OP. Operative intervention occurred more frequently in infants with PVG compared with infants without PVG (OR, 2.5; CI, 1.37-4.76; P = .003)--only 48% of infants with PVG underwent OP. Among the variables, gestational age, severe NEC (Bell stage III), severe intramural gas (in all 4 abdominal quadrants), and the presence of PVG, severe NEC was most highly associated with OP (OR, 77.47; CI, 10.36-580.16; P < .0001). Bell stage III NEC was present in 98% of infants who underwent OP compared with 40% of infants without OP ( P < .0001). Of all infants with NEC, 37 (19%) died. Mortality was higher among infants who underwent OP (33% vs 12%; P < .0003). A multivariate regression model identified Bell stage III (OR, 3.74; CI, 1.20-11.62; P = .02), but neither PVG nor OP, to be significantly associated with mortality. Of interest is that survival in infants with PVG was greater (but not significantly so) than in infants without PVG in both OP (74% vs 59%) and non-OP (91% vs 87%) groups. Furthermore, 30 of 64 (47%) infants with PVG survived without OP, and of all 33 infants with PVG who did not undergo OP, 30 (91%) infants survived. CONCLUSIONS: Decision for OP should be based on the severity of NEC and not on the presence of PVG alone because nearly half of infants with PVG survive without OP. Overall, the presence of PVG does not increase the risk of mortality among infants with NEC. Severe NEC, but not OP, is associated with higher mortality.

Chi-Square Distribution↗
PubMed2004

Comparison of beractant and calfactant in a neonatal intensive care unit.

PURPOSE: The relative efficacy, complications and cost of beractant and calfactant were studied. METHODS: All patients admitted to a neonatal intensive care unit between January and November 2001 with an estimated gestational age (EGA) of < or = 29 weeks were included in this retrospective study. Neonates with an EGA of > 29 weeks who required surfactant treatment because of respiratory distress syndrome (RDS) were also enrolled. The prophylaxis group included all neonates with an EGA of < or = 29 weeks who received a prophylactic dose of surfactant within one hour of birth. The rescue group included neonates who did not receive a prophylactic dose, who demonstrated radiographic and clinical signs of RDS, and who received a rescue dose of surfactant. RESULTS: Of 139 patients reviewed, 107 (77%) were included in the study. No significant difference between the two surfactants in either group was found in mean fraction of inspired oxygen (FiO2) at 72 hours, time to an FiO2 of 30%, total number of doses per patient, and complications. The cost of surfactant administered per patient did not differ significantly between the two drugs in each group, but the cost of the amount wasted per patient did. The mean total cost of prophylaxis per patient was thus significantly higher for calfactant ($513) than for beractant ($379). CONCLUSION: Beractant and calfactant were similar in terms of efficacy, safety, and total number of doses per patient. However, calfactant was significantly more costly because of greater product waste.

Administration, Inhalation↗
PubMed2004

Surgical management of bowel perforations and outcome in very low-birth-weight infants (< or =1,200 g).

PURPOSE: The efficacy of peritoneal drainage (PD) as an alternative to laparotomy (LAP) in the management of bowel perforation (PRF) in very low-birth-weight infants (VLBW < or = 1,200 g) remains uncertain. The authors hypothesized that survival of VLBW infants with PRF depends on the severity of illness rather than on the initial surgical approach. METHODS: Demographic, clinical, and outcome data on all VLBW infants were abstracted prospectively over a 12(1/2)-year period. Infants with PRF were stratified by PD or by LAP. Illness acuity was compared using the sum of a 7-point scoring system based on the clinical signs determined to be of prognostic significance. The factors associated with adverse outcome and the epidemiology of PRF were also examined. RESULTS: Of 937 infants, 78 with PRF required surgical intervention, consisting of PD in 32 (41%) and LAP in 46 (59%). Mean birth weight, illness acuity score, and the number of infants with NEC were significantly lower in PD (P =.0005). A higher proportion of PD infants received indomethacin (P =.01). There were no other differences between the 2 groups. Regardless of the choice of procedure, birth weight did not affect mortality rate; however, a shorter interval between PRF identification and surgical intervention was associated with improved survival rate (P =.001). Postoperative liver dysfunction, short gut syndrome, and enteric stricture were more common among LAP. Mortality rate, however, did not differ. When severe thrombocytopenia (P <.03) or neutropenia was present (P <.03), outcome of LAP was better than PD. Rescue LAP for 8 of rapidly deteriorating PD infants saved 5. Regardless of surgical approach, coagulopathy (P <.003), severe thrombocytopenia (P <.005), neutropenia (P <.0001), and multiple organ failure (P <.0001) were all predictive of fatality. CONCLUSIONS: Choice of surgical approach should be based on the underlying illness and not on birth weight. In the presence of clinical indication of necrotic gut, or profound abdominal infection, LAP is a better choice. PD, however, is far less morbid and should be considered for isolated PRF. Rescue LAP must be considered without delay when PD fails.

Constriction, Pathologic↗
PubMed2004

Rotavirus-associated necrotizing enterocolitis: an insight into a potentially preventable disease?

PURPOSE: The aim of this study was to test the hypothesis that rotavirus-associated necrotizing enterocolitis (NEC + RV) differs from NEC associated with other organisms (NEC-RV). METHODS: Neonates with modified Bell stage II or higher NEC were identified. Demographic, clinical, and outcome information was collected prospectively. Fecal specimens from all infants were tested for confirmation of rotavirus infection (RVI) by immunoelectron microscopy (IEM). RESULTS: Of 2,444 admissions in the neonatal intensive care unit (NICU), 129 (5.3%) had NEC. Thirty-eight (29%) were rotavirus positive. The 2 groups did not differ in maternal or neonatal characteristics. Stage III or higher NEC was more common in the NEC-RV infants (62% v. 39%; P =.032), whereas recurrence was more common in NEC + RV group (P <.0001). The predominant distribution of nondiffuse pneumatosis (n = 52) was right sided in NEC-RV group and left sided in NEC + RV group (P <.0001). Surgical intervention (SI) did not differ between the 2 groups. The complications and mortality rates also were similar. Severe pneumatosis (P =.009) and severe thrombocytopenia (Platelet count < 50,000/mm3; P <.0001) increased, while human milk feedings decreased (P =.022) the odds for surgery. The annual distribution of NEC + RV paralleled RVI in the community. CONCLUSIONS: Generally, NEC + RV is a less severe disease than NEC - RV as classified by modified Bell staging. However, it can reach advanced stages obscuring distinction from NEC - RV. Indications for surgery should not be altered by identification of RVI in these infants. Monitoring RVI in the community, adhering to infection control measures, human milk feedings, and improving neonatal immunity against RVI may reduce the incidence of NEC + RV.

Community-Acquired Infections↗
PubMed2003

Metathetical conversion of Nd2O3 nanoparticles into NdS2 polysulfide nanoparticles at low temperatures using boron sulfides.

A new simple metathetical sulfidation method using boron sulfides has been developed to prepare nanoparticles of NdS(2) via conversion of ca. 50-nm-sized nanoparticles of Nd(2)O(3) at 450 degrees C, in which boron and sulfur powders form boron sulfides in situ and evaporate to sulfidize the oxide. The X-ray powder diffraction analysis revealed that the products were purely NdS(2), and the atomic absorption spectrometric analysis confirmed nonexistence of boron in the products after washing with water. The detailed TEM studies showed that the NdS(2) nanoparticles maintained the original size of the oxide particles without fusion during the low-temperature sulfidation process.

Journal Article↗
PubMed2003

Ferromagnetism above room temperature in bulk and transparent thin films of Mn-doped ZnO.

The search for ferromagnetism above room temperature in dilute magnetic semiconductors has been intense in recent years. We report the first observations of ferromagnetism above room temperature for dilute (<4 at.%) Mn-doped ZnO. The Mn is found to carry an average magnetic moment of 0.16 mu(B) per ion. Our ab initio calculations find a valance state of Mn(2+) and that the magnetic moments are ordered ferromagnetically, consistent with the experimental findings. We have obtained room-temperature ferromagnetic ordering in bulk pellets, in transparent films 2-3 microm thick, and in the powder form of the same material. The unique feature of our sample preparation was the low-temperature processing. When standard high-temperature (T > 700 degrees C) methods were used, samples were found to exhibit clustering and were not ferromagnetic at room temperature. This capability to fabricate ferromagnetic Mn-doped ZnO semiconductors promises new spintronic devices as well as magneto-optic components.

Journal Article↗
PubMed2003

Lethal neonatal carnitine palmitoyltransferase II deficiency: an unusual presentation of a rare disorder.

A term male newborn, appropriate for gestational age, developed hypothermia, severe cardiac dysrrhythmia, and nonoliguric hyperkalemia within 24 hours of birth. Despite the prenatal identification of cystic renal dysplasia without oligohydramnios, at birth, a solitary left leg vascular hemangioma and large palpable kidneys were the only anomalies. Gradually hypotonia, lethargy, and poor feeding developed and by 20 hours of age recurrent cardiac dysrrhythmias, myocardial dysfunction, and renal insufficiency with intermittent hyperkalemia were apparent. Episodes of apnea developed on day 7 followed by respiratory failure, recurrent cardiac dysrrhythmias, and death on day 12. Eventually laboratory and autopsy findings confirmed the diagnosis of lethal neonatal carnitine palmitoyltransferase II deficiency.

Abnormalities, Multiple↗
PubMed2002

Clinical manifestations of rotavirus infection in the neonatal intensive care unit.

OBJECTIVES: This report describes clinical signs of rotavirus infection (RVI) among neonates admitted to a neonatal intensive care unit (NICU), compares these signs between term and preterm neonates and assesses the seasonal distribution of RVI in the NICU with that of the community. METHODS: After an initial prevalence study of 28 days, a prospective longitudinal study in the NICU was conducted. During the next 48 months from December 1, 1991 to November 30, 1995, term and preterm NICU patients were evaluated daily for pre-defined deviations in their baseline gastrointestinal status. Fecal specimens of neonates who fulfilled the entry criteria were tested for rotavirus by a monoclonal antibody-based enzyme immunoassay and by immunoelectron microscopy. Demographic and outcome data for these neonates were collected. In addition data assessing RVI in the community were collected during this period. RESULTS: The prevalence of RVI among NICU patients was 18.4%. Of 194 neonates included in the longitudinal study, 95 had RVI. Neonates with RVI differed from those without RVI with respect to frequent stooling (P = 0.0005), higher percentage of bloody mucoid stools (P = 0.003) and higher percentage of watery stools (P = 0.023). The odds of these three clinical outcomes were approximately 2.5 times higher in neonates with RVI than in neonates without RVI. Among neonates included in the study advanced necrotizing enterocolitis occurred at the same rate (15%) among those with and without RVI. Comparisons between term and preterm neonates with RVI showed that frequent stooling (P = 0.003) and watery stools (P = 0.0001) occurred more often among term neonates, whereas bloody mucoid stools (P = 0.001), abdominal distention (P = 0.03) and intestinal dilatation (P = 0.016) were more common in preterm neonates. The seasonal distribution of RVI in NICU paralleled its distribution in the community. CONCLUSION: RVI appears prevalent in the NICU setting. An absence of watery stools in a neonate should not preclude consideration of RVI when evaluating gastrointestinal signs among neonates. The clinical spectrum of RVI differs in term and preterm infants.

Analysis of Variance↗
PubMed2001

Design and Applications of Environmental Cell Transmission Electron Microscope for In Situ Observations of Gas-Solid Reactions.

The environmental transmission electron microscopy (E-TEM) is a budding technique for in situ study of gas-solid chemical reactions with numerous applications. Recent improvements in the design have made it possible not only to obtain atomic level information but also the chemical information during the reaction by incorporating an imaging filter or electron energy-loss spectrometer to an E-TEM. We have been involved in modifying a couple of microscopes to incorporate environmental cells in order to convert them into E-TEMs. These microscopes have been used to obtain atomic level information of the structural and chemical changes during dynamic processes by in situ electron diffraction, high-resolution imaging, and electron energy-loss spectroscopy. The applications include, but are not limited to, oxidation, reduction, polymerization, nitridation, dehydroxylation, hydroxylation, chemical vapor deposition, etc. We report recent developments in the design and application along with the limitations of an E-TEM.

Journal Article↗