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Derris scandens (Roxb.) Benth. (Family: Fabaceae), a recognized medicinal plant colloquially known as ‘Kalilata’ in Bangladesh, has been traditionally used as analgesic in Thailand. This study was intended to evaluate and compare the antimicrobial and membrane stabilizing potentials among the methanol extracts of D. scandens leaf and stem, and their fractionates. The stem and leaves of the plant were extracted by methanol separately and fractioned into aqueous, dicholoromethane (DCM), ethyl acetate and n-hexane soluble fractions. They were tested for antimicrobial activity by using the agar-well diffusion method where ciprofloxacin and fluconazole were used as references. The highest antimicrobial activity was observed against a Gram-negative bacteria (Escherichia coli) by the DCM soluble fraction of the leaf and stem extracts with 20 mm and 15 mm zones of inhibition, respectively. The n-hexane soluble fraction of methanol extract of stem revealed weak to moderate antimicrobial activity against Gram-positive bacteria. The ethyl acetate soluble fractionates of methanol extracts of leaf and stem showed similar antifungal property against Saccharomyces cerevisiae with a zone of inhibition of 12 mm. The membrane stabilizing potential of the extractives was estimated based on the prevention of hemolysis of RBC prompted by hypotonic solution as well as heat. The n-hexane and DCM soluble fractions of both extracts showed around 75% inhibition of hypotonic solution- and heatinduced hemolysis. All in all, the extracts and several fractionates showed moderate antimicrobial and membrane stabilizing properties and further investigations are warranted to find out active phytoconstituents responsible for these properties. Bangladesh Pharmaceutical Journal 26(1): 67-72, 2023 (January)

BackgroundSepsis severity scores are used in clinical practice and trials to define risk groups. There are limited data to derive hospital-based sepsis severity scores for neonates and young infants in high-burden low- and middle-income country (LMIC) settings where trials are urgently required. We aimed to create linked sepsis severity and recovery scores applicable to hospitalized neonates and young infants in LMIC which could be used to inform antibiotic trials.Methods & FindingsA prospective observational cohort study was conducted across 19 hospitals in 11 countries in sub-Saharan Africa, Asia, Latin America and Europe. Infants aged 3204 infants were enrolled between 2018-2020. Median age was 5 days (IQR 2-15), 90.4% (n=2,895) were A related NeoSep Recovery Score based on evolving post-baseline clinical signs and supportive care discriminated well between infants who died or survived the following day or subsequent few days. The area under the ROC curve for score on day 2 and death in the following 5 days was 0.82 (95%CI 0.78-0.85) and 0.85 (95%CI 0.78-0.93) in the derivation and validation data, respectively.ConclusionThe baseline NeoSep Severity Score predicted 28-day mortality and could identify infants with high risk of mortality for inclusion in hospital-based sepsis trials. The NeoSep Recovery Score predicts day-by-day inpatient mortality and could, with further validation, help to identify poor response to antibiotics.Author SummaryWhy was this study done?➣Evidence to guide hospital-based antibiotic treatment of sepsis in neonates and young infants is scarce, and clinical trials are particularly urgent in low- and middle-income (LMIC) settings where antimicrobial resistance threatens to undermine existing guidelines➣There is limited data to inform the design of antibiotic trials in LMIC settings, particularly to define risk stratification and inclusion and escalation criteria in hospitalised neonates and young infantsWhat did the researchers do and find?➣To our knowledge this is the first global, prospective, hospital-based observational study of clinically diagnosed neonatal sepsis across 4 continents including LMIC settings, with extensive daily data collection on clinical status, antibiotic use and outcomes.➣There was a high mortality among infants with sepsis in LMIC hospital settings. 4 non-modifiable and 6 modifiable factors predicted mortality and were included in a NeoSep Severity score which defines patterns of mortality risk at baseline➣A NeoSep Recovery Score including the same modifiable factors (with the addition of cyanosis) predicted mortality on the following day during the course of treatment.What do these findings mean?➣The NeoSep Severity Score and NeoSep Recovery score are now informing inclusion and escalation criteria in the NeoSep1 antibiotic trial (ISRCTN48721236) which aims to identify novel first- and second-line empiric antibiotic regimens for neonatal sepsis➣The NeoSep Severity Score could be used to predict mortality at baseline in future studies of targeting resources in routine care. With further validation, the NeoSep Recovery Score could potentially be used to identify poor response to empiric antibiotic treatment

Background We conducted a cost of illness study to assess the economic burden of pediatric enteric fever (typhoid and paratyphoid) in Bangladesh. Results can inform public health policies to prevent enteric fever. Methods The study was conducted at 2 pediatric health facilities in Dhaka. For the patient and caregiver’s perspective, we administered questionnaires on costs incurred from illness onset until the survey dates to caregivers of patients with blood culture positive cases at enrollment and 6 weeks later to estimate the direct medical, direct nonmedical, and indirect costs. From the perspective of the health care provider, we collected data on quantities and prices of resources used by the 2 hospitals to estimate the direct medical economic costs to treat a case of enteric fever. We collected costs in Bangladeshi takas and converted them into 2018 US dollars. We multiplied the unit cost per procedure by the frequency of procedures in the surveillance case cohort to calculate the average cost per case. Results Among the 1772 patients from whom we collected information, the median cost of illness per case of enteric fever from the patient and caregiver perspective was US $64.03 (IQR: US $33.90 –$173.48). Median direct medical and nonmedical costs per case were 3% of annual labor income across the sample. From the perspective of the healthcare provider, the average direct medical cost per case was US $58.64 (range: US $37.25 at Hospital B, US $73.27 at Hospital A). Conclusions Our results show substantial economic burden of enteric fever in Bangladesh, with higher costs for patients receiving inpatient care. As antimicrobial resistance increases globally, the cost of illness could increase, due to more expensive and potent drugs required for treatment.

World Health Organization (WHO) preferred product characteristics describe preferences for product attributes that would help optimize value and use to address global public health needs, with a particular focus on low- and middle-income countries. Having previously published preferred product characteristics for both maternal and paediatric respiratory syncytial virus (RSV) vaccines, WHO recently published preferred product characteristics for monoclonal antibodies to prevent severe RSV disease in infants. This article summarizes the key attributes from the preferred product characteristics and discusses key considerations for future access and use of preventive RSV monoclonal antibodies.

Recent studies of SiGeSn materials and optoelectronic devices hold great promise for photonics integrated circuits (PICs) on Si platform featuring scalable, cost-effective, and power-efficient. Thanks to the breakthrough of low temperature material growth techniques, device-quality level materials have been grown, following by the demonstration of light-emitting diodes, photodetectors, and optically pumped and electrically injected band-to-band lasers. While the exciting developments in bulk devices were reported, the quantum wells (QWs) have been investigated targeting the dramatically improved and/or novel device performance via variety of quantum confinement effects. In this review, we summarize the recent progress on development of SiGeSn QWs, including the fundamental optical and transition studies and optoelectronic device applications. The inspirational results reveal the possibility of all-group-IV PICs with photonics and electronics monolithically integrated on a single-chip.

Background Seasonal ranging pattern of the Asian Elephants was assessed within two major Protected Areas, namely Chunati Wildlife Sanctuary and Teknaf Wildlife Sanctuary situated in the southern Bangladesh, for the period between November 2016 and May 2018. The objective of this study was to see how do the elephants move across the Protected Area landscapes, what was the linkage between the water sources and elephant’s seasonal movement patterns and how does vegetation cover link to elephant movement. Methods The ranging pattern was analyzed using the elephant dung distribution data. Normalized Difference Vegetation Index and Normalized Difference Water Index were estimated through satellite image analysis. Results Study clearly indicated that the ranging pattern of elephants fully depends on the vegetation and water sources. The areas where water sources and vegetation coverage were good, elephant movement was higher. The study identified few areas of these two Protected Areas where both vegetation coverage and water sources were visible and those areas as hot-spots for elephants. Conclusions The findings of this study can be used in conservation and management of elephants, particularly through the protection of preferred water sources and vegetation covered areas. In future these areas need to be protected and take proper management interventions.

Background Sepsis is a major contributor to neonatal mortality, particularly in low-income and middle-income countries (LMICs). WHO advocates ampicillin–gentamicin as first-line therapy for the management of neonatal sepsis. In the BARNARDS observational cohort study of neonatal sepsis and antimicrobial resistance in LMICs, common sepsis pathogens were characterised via whole genome sequencing (WGS) and antimicrobial resistance profiles. In this substudy of BARNARDS, we aimed to assess the use and efficacy of empirical antibiotic therapies commonly used in LMICs for neonatal sepsis. Methods In BARNARDS, consenting mother–neonates aged 0–60 days dyads were enrolled on delivery or neonatal presentation with suspected sepsis at 12 BARNARDS clinical sites in Bangladesh, Ethiopia, India, Pakistan, Nigeria, Rwanda, and South Africa. Stillborn babies were excluded from the study. Blood samples were collected from neonates presenting with clinical signs of sepsis, and WGS and minimum inhibitory concentrations for antibiotic treatment were determined for bacterial isolates from culture-confirmed sepsis. Neonatal outcome data were collected following enrolment until 60 days of life. Antibiotic usage and neonatal outcome data were assessed. Survival analyses were adjusted to take into account potential clinical confounding variables related to the birth and pathogen. Additionally, resistance profiles, pharmacokinetic–pharmacodynamic probability of target attainment, and frequency of resistance (ie, resistance defined by in-vitro growth of isolates when challenged by antibiotics) were assessed. Questionnaires on health structures and antibiotic costs evaluated accessibility and affordability. Findings Between Nov 12, 2015, and Feb 1, 2018, 36 285 neonates were enrolled into the main BARNARDS study, of whom 9874 had clinically diagnosed sepsis and 5749 had available antibiotic data. The four most commonly prescribed antibiotic combinations given to 4451 neonates (77·42%) of 5749 were ampicillin–gentamicin, ceftazidime–amikacin, piperacillin–tazobactam–amikacin, and amoxicillin clavulanate–amikacin. This dataset assessed 476 prescriptions for 442 neonates treated with one of these antibiotic combinations with WGS data (all BARNARDS countries were represented in this subset except India). Multiple pathogens were isolated, totalling 457 isolates. Reported mortality was lower for neonates treated with ceftazidime–amikacin than for neonates treated with ampicillin–gentamicin (hazard ratio [adjusted for clinical variables considered potential confounders to outcomes] 0·32, 95% CI 0·14–0·72; p=0·0060). Of 390 Gram-negative isolates, 379 (97·2%) were resistant to ampicillin and 274 (70·3%) were resistant to gentamicin. Susceptibility of Gram-negative isolates to at least one antibiotic in a treatment combination was noted in 111 (28·5%) to ampicillin–gentamicin; 286 (73·3%) to amoxicillin clavulanate–amikacin; 301 (77·2%) to ceftazidime–amikacin; and 312 (80·0%) to piperacillin–tazobactam–amikacin. A probability of target attainment of 80% or more was noted in 26 neonates (33·7% [SD 0·59]) of 78 with ampicillin–gentamicin; 15 (68·0% [3·84]) of 27 with amoxicillin clavulanate–amikacin; 93 (92·7% [0·24]) of 109 with ceftazidime–amikacin; and 70 (85·3% [0·47]) of 76 with piperacillin–tazobactam–amikacin. However, antibiotic and country effects could not be distinguished. Frequency of resistance was recorded most frequently with fosfomycin (in 78 isolates [68·4%] of 114), followed by colistin (55 isolates [57·3%] of 96), and gentamicin (62 isolates [53·0%] of 117). Sites in six of the seven countries (excluding South Africa) stated that the cost of antibiotics would influence treatment of neonatal sepsis. Interpretation Our data raise questions about the empirical use of combined ampicillin–gentamicin for neonatal sepsis in LMICs because of its high resistance and high rates of frequency of resistance and low probability of target attainment. Accessibility and affordability need to be considered when advocating antibiotic treatments with variance in economic health structures across LMICs. Funding The Bill & Melinda Gates Foundation.

Most of the current evidence regarding pneumococcal upper respiratory colonization in adults suggests that despite high disease burden, carriage prevalence is low. Contemporary studies on adult pneumococcal colonization have largely followed the pediatric approach by which samples are obtained mostly from the nasopharynx and bacterial detection is evaluated by routine culture alone. Recent evidence suggests that the 'pediatric approach' may be insufficient in adults and pneumococcal detection in this population may be improved by longitudinal studies that include samples from additional respiratory sites combined with more extensive laboratory testing.In this article, relevant literature published in peer review journals on adult pneumococcal colonization, epidemiology, detection methods, and recommendations were reviewed.Respiratory carriage of

GeSn-based quantum wells (QWs) are of great interests for the development of all-group-IV optoelectronic devices such as lasers. Using a GeSn buffer and SiGeSn barrier has been studied with the aim of obtaining a direct bandgap well and increasing the carrier confinement. However, the carrier collection efficiency with such a configuration remains unsatisfactory. In this work, a single QW with additional GeSn barrier inserted between the GeSn well and the SiGeSn barrier was grown and characterized. Under relatively low carrier injection, the photoluminescence results show dramatically enhanced emission from the QW compared to the reference samples with only SiGeSn barrier, indicating a significantly improved carrier collection efficiency of the well.

Dengue has been regularly reported in Dhaka, Bangladesh, since a large outbreak in 2000. However, to date, we have limited information on the seasonal distribution of dengue disease and how case distribution correlates with climate. Here, we analyzed dengue cases detected at a private diagnostic facility in Dhaka during 2010–2014. We calculated Pearson cross-correlation coefficients to examine the relationship between the timing of cases and both rainfall and temperature. There were 2,334 cases diagnosed during the study period with 76% over the age of 15 years. Cases were reported in every month of the study; however, 90% of cases occurred between June and November. Increases in rainfall were correlated with increases in cases 2 months later (correlation of 0.7). The large proportion of adult cases is consistent with substantial population susceptibility and suggests Dhaka remains at risk for outbreaks. Although cases occurred year-round, public health preparedness should be focused during peak months.

We have theoretically investigated the high harmonic generation (HHG) spectra of \(\textrm{H}_2^+ \) and HD + using a time-dependent wave packet approach for the nuclear motion with pulsed lasers of peak intensities (I0) of 3.5 ×1014 and 4.5 ×1014 W/cm2, wavelengths (λL) of 800 and 1064 nm, and pulse durations (T) of 40 and 50 fs, for initial vibrational levels v0 = 0 and 1. We have argued that for these conditions the harmonic generation due to the transitions in the electronic continuum by tunnelling or multiphoton ionization will not be important. Thus, the characteristic features of HHG spectra in our model arise only due to the nuclear motions on the two lowest field-coupled electronic states between which both interelectronic and intraelectronic (due to intrinsic dipole moments, for HD + ) radiative transitions can take place. For HD + , the effect of nonadiabatic (NA) interaction between the two lowest Born–Oppenheimer (BO) electronic states has been taken into account and comparison has been made with the HHG spectra of HD + obtained in the BO approximation. Even harmonics and a second plateau in the HHG spectra of HD + with the NA interaction and hyper-Raman lines in the spectra of both \(\textrm{H}_2^+ \) and HD + for v0 = 1 have been observed for higher value of I0 or λL. Our calculations indicate reasonable efficiencies of harmonic generation even without involving the electronic continuum.

We have investigated the angular distribution of photofragments resulting from multiphoton above threshold dissociation (ATD) of HD+ from initial bound levels νi=0, 1, 2 and Ji=0 induced by linearly (↕) and circularly (↻) polarized laser fields of intensities I=1, 5, and 10 TW/cm2 and frequency ω=30 333 cm−1 (λ=329.7 nm). The time-independent close coupling (CC) method has been used. Molecular rotation has been taken into account by including 72 channels with J=0–7 and number of photons n=−1–7, for ↕ polarization. In case of ↻ polarization, the channel number reduced to 48. All the radiative couplings including those due to the intrinsic dipole moments of HD+ have been considered in a truncated length gauge form of interaction. For (net) one-photon dissociation (from νi=1, 2) by bond softening, the alignment of the angular distribution of photofragments increases with intensity (1–10 TW/cm2), for both ↕ and ↻ polarizations. The angular distributions for (net) two-photon fragmentation via the adiabatic pat...

We have theoretically investigated the branching in population transfer in H2 by chirped adiabatic Raman passage from the ground vg=0, Jg=0 level to the final rotational levels Jf=0 (Q-branch) and Jf=2 (S-branch) of the fundamental transition (vf=1) in the ground X 1Σg+ state via the nonresonant intermediate B 1Σu+ and C 1Πu+ states. The density matrix technique has been employed to describe the time evolution of the process. We have evaluated the rotational branching of transferred population in the final levels using linearly chirped pump and Stokes laser pulses with different chirp rates and chirp widths. Both the pulses are considered to have the same temporal shape, duration, peak intensity, and linear parallel polarizations. It has been observed that for negative chirping of the pump laser and positive chirping of the Stokes laser, branching in population transfer to the Q- and S-branches occur for fast chirping and short pulses while for slow chirping and long pulses, more and more population build...

Polarization effects on population transfer by stimulated Raman transition using overlapping time dependent pump and Stokes laser pulses from the ground X 1Σ /+ (v g=0, J g=1) level of H2 to the final X 1Σ /+ (v f=1, J f=1) level via the intermediate B 1Σ /+ (v i=14, J i=0,2), C 1Π /+ (v i=3, J i=2) and C 1Π /− (v i=3, J i=1) levels have been theoretically investigated by applying the density matrix formalism. We have studied in detail the dependence of the population transfer on time delay between two pulses for the cases of on-resonance excitations considering linear parallel and same-sense circular polarizations of the fields. The pump and Stokes fields are taken as having Gaussian pulse shapes with peak intensities I /0 (I /0 )=2 × 106 and 1 × 107 W/cm2. Density matrix equations have been solved for each value of the magnetic quantum number M g(0, ±1) of the initial ground level taking into account the M g dependence of the Rabi frequencies. M g — averaged population transfer to the final level has also been calculated. For resonance excitations to the B(14, 0) or C(3, 1) levels, appreciable population transfer is achieved for intuitive pulse order for some particular values of M g and M i (magnetic quantum number of the resonant intermediate level) depending on the nature of polarizations. The calculated values of M g — averaged population transfer for the two cases of polarizations show that for on-resonance excitation to the B(14, 0) or the C(3, 1) level, linear parallel polarization of the laser fields yield more transfer efficiency whereas for resonance excitation to the B(14, 2) level, larger population transfer results from the same-sense circular polarizations. For resonance excitation to the C(3, 2) level, M g — averaged population is found to be almost polarization independent. The calculations for the six-level H2 system reveal some interesting features of polarization effects on the population transfer efficiency.

We have theoretically investigated the population transfer in a four-level ${\mathrm{H}}_{2}$ system by stimulated Raman transition from the ground $X{}^{1}{\ensuremath{\Sigma}}_{g}^{+}({\ensuremath{\nu}}_{g}{=0,J}_{g}=0)$ level to higher rovibrational levels $({\ensuremath{\nu}}_{f}{,J}_{f})$ of the $X{}^{1}{\ensuremath{\Sigma}}_{g}^{+}$ state via the excited intermediate $B{}^{1}{\ensuremath{\Sigma}}_{u}^{+}({\ensuremath{\nu}}_{i}{=14,J}_{i}=1)$ and $C{}^{1}{\ensuremath{\Pi}}_{u}^{+}({\ensuremath{\nu}}_{i}{=3,J}_{i}=1)$ levels coupled with each other by nonadiabatic interaction, using time-dependent overlapping pump and Stokes laser fields. The density-matrix treatment, which permits the convenient inclusion of the spontaneous emissions from the intermediate levels, has been employed to describe the dynamics of the two-photon Raman resonance process. The present study performs the calculations of final populations (after both the pulses are over) of the ground and terminal levels for Q-branch ${(J}_{f}=0)$ fundamental $({\ensuremath{\nu}}_{f}=1)$ and first overtone $({\ensuremath{\nu}}_{f}=2)$ transitions and the S-branch ${(J}_{f}=2)$ fundamental $({\ensuremath{\nu}}_{f}=1)$ transition as a function of time delay between the two pulses for the cases of on-resonance as well as off-resonance excitations in a wide range $(2\ifmmode\times\else\texttimes\fi{}{10}^{5}\char21{}2\ifmmode\times\else\texttimes\fi{}{10}^{7}{\mathrm{W}/\mathrm{c}\mathrm{m}}^{2})$ of peak intensities ${I}_{P}^{0}$ ${(I}_{S}^{0})$ of the pump (Stokes) fields. Both fields are assumed to have the same temporal shape, duration, peak intensities, and linear parallel polarizations. The accurate values of spontaneous radiative relaxation rates of the intermediate levels to the initial and final levels, taking into account their J and M dependence, are explicitly included in our calculations. The pulse width (full width at half maximum) ${\ensuremath{\tau}}_{p}$ is taken as 170 ns so that total spontaneous decay can occur during the pulse duration. The transfer efficiency is found to be very sensitive to the peak intensities of the laser pulses in each case of transition considered. Special attention is paid to the effects of the nonadiabatic (NA) interaction between $B(14,1)$ and $C(3,1)$ levels on population transfer efficiency. Calculations are also done in some particular cases using the adiabatic Born-Oppenheimer (ABO) approximation. The results with ABO approximation are found to differ remarkably from those obtained including NA interaction. Our calculations for the four-level ${\mathrm{H}}_{2}$ system reveal that almost complete population is transferred in counterintuitive pulse order for both on-resonance and off-resonance excitations with intermediate and high values of ${I}_{P}^{0}$ ${(I}_{S}^{0}).$ For intuitive pulse sequence also a large population transfer is achieved for on-resonance excitation at intermediate values of ${I}_{P}^{0}$ ${(I}_{S}^{0})$ and for off-resonance excitation at intermediate and high values of ${I}_{P}^{0}$ ${(I}_{S}^{0}).$

We have studied multiphoton above-threshold dissociation (ATD) of and by a time-independent close-coupling (CC) method over a wide range of intensities for three initial bound states (v = 0, 1, 2 and J = 0) at a laser frequency of . Molecular rotation is taken into account by including 30 channels with J = 0 - 5 for and 20 channels with J = 0 - 7 for and number of absorbed photons n = 1 - 4. All the radiative couplings (including those due to the permanent dipole moment of ) have been considered in a truncated length-gauge form of interaction. At lower intensities the total dissociative decay is exponential, but at high intensity several dressed states with different linewidths contribute to the decay and no single decay rate can be defined. Use of the proper potential surfaces for , including intramolecular nonadiabatic coupling, enables us to obtain the branching ratios between the production of and fragments. The branching ratios for different numbers of photon absorption (n = 1, 2, 3) change dramatically with intensity. For , branching to channels, forbidden in by symmetry, may become dominant over a certain range of intensity. We have tried to interpret these intensity dependences in terms of the motion of the nuclei on the adiabatic field + molecule potential surfaces.

We have theoretically investigated the high harmonic generation (HHG) spectra of H2 + and HD + using a time-dependent wave packet approach for the nuclear motion with combined two-colour (1ω L –3ω L ) pulsed lasers for ω L corresponding to wavelengths 1064 nm and 800 nm. The 1ω L and 3ω L lasers have peak intensities of I 1 0 = 5.0×1013 W/cm2 and I 2 0 = 2.0×1014 W/cm2, respectively. We have taken the pulse duration of T = 50 fs for both the fields, and the molecular initial vibrational level v 0 = 0. We have argued that for these combinations, the harmonic generation due to transitions in the electronic continuum by tunnelling or multiphoton ionization may be neglected and only the electronic transitions within the two lowest electronic states would be important. Thus, the characteristic features of HHG spectra in the two-colour field are determined, in our model, by the nuclear motions on the two lowest field-coupled electronic states between which interelectronic and intraelectronic (due to the intrinsic dipole moments in case of HD + ) radiative transitions can take place. We have studied the role of relative phase (φ) of the two fields on the HHG spectra of the molecular ions. In case of HD + , the effect of nonadiabatic (NA) nonradiative interaction between the two lowest Born-Oppenheimer (BO) electronic states (1sσ g , 2pσ u ) has been taken into account. Our calculations give realistic HHG spectra which are reasonably efficient and extended for both H2 + and HD + in the mixed two-colour field without involving the electronic continuum. The use of two-colour (1ω L –3ω L ) field enables us to generate high harmonics beyond that achievable with a single 1ω L or 3ω L field of the corresponding intensity, frequency and pulse time.

We present a theoretical study of resonant two-photon dissociation (TPD) of the molecule in the presence of pulsed two-colour laser fields using the density matrix formalism. The study includes the calculation of dissociation probabilities and decay rates as functions of time and the variation of total dissociation probabilities with detuning when both fields are assumed to have the same temporal shape and duration. Results are reported for two simultaneous laser pulses as well as for two pulses with a time delay. The investigations were done with different values of peak intensities , for the initial and intermediate levels as v = 0, J = 0 and v'=17, J'=1, respectively, of the ground electronic state and the final continuum energy reached by photons was taken to be . The time variation and delay between pulses lead to interesting features in the time-dependent decay rates and spectral shapes of total dissociation probabilities.

The time-dependent dissociation probabilities, lineshapes of dissociation rates and branching ratios of photofragments between the neutral hydrogen and deuterium channels have been investigated for resonant two-photon dissociation of HD+ from the ground level in the presence of two laser fields of different intensities I1, I2 and frequencies omega 1, omega 2 using the resolvent operator formalism. The symmetry breaking due to non-adiabatic (NA) interactions causes splitting between the two asymptotic channels, unlike the Born-Oppenheimer (BO) approximation. Simultaneous dissociation to the continua of the two electronic states at two different energies occurs through the absorption of either omega 1+ omega 2 or 2 omega 1 photons. Only the field of frequency omega 1 was considered to resonantly couple the near-resonant level nu '=17, J'=1 or nu '=18, J'=1 to the ground level nu =0, J=0. Non-resonant discrete and continuum states significantly affect the dissociation process in the case of high intensity fields. The electric field gauge (E.d) form of interaction Hamiltonian has been used in the computation of various laser-dependent parameters. The results with NA coupling included are found to deviate appreciably from those obtained with the BO approximation.

Resonance-enhanced two-photon dissociation from the ground $^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{g}}^{+}$ (${\mathit{v}}_{\mathit{g}}$=0,${\mathit{J}}_{\mathit{g}}$) state of ${\mathrm{H}}_{2}$ to the final continua of EF, GK, and I states has been studied using both linear parallel and crossed polarizations of the two-photon fields. The first field creates an aligned population in the intermediate resonant state B $^{1}\mathrm{\ensuremath{\Sigma}}_{\mathrm{u}}^{+}$ (${\mathrm{v}}_{\mathrm{i}}$=0,3,${\mathit{J}}_{\mathit{i}}$) for which the reduced density-matrix description has been adopted. This intermediate state is dissociated through coherent excitation of a number of near-resonant discrete vibrational levels, bound and quasibound, of HH\ifmmode\bar\else\textasciimacron\fi{} and I, respectively, as well as by direct transition to the continua of EF, GK, and I by absorption from the second field. The nonadiabatic interaction of the HH\ifmmode\bar\else\textasciimacron\fi{} and I levels with the continuum of GK gives these states predissociating characteristics and the whole process can be formulated in terms of overlapping Fano resonances. The nonadiabatic couplings of the continua of I and EF with the HH\ifmmode\bar\else\textasciimacron\fi{} bound levels have been neglected because of their smallness. The interference of the transition amplitudes to different overlapping predissociating resonances gives the resultant structure in the dissociation probability which is studied for the second photon wavelength covering a range between the dissociation threshold of the final states and the ionization threshold of ${\mathrm{H}}_{2}$. The dissociation cross section obtained from these nonadiabatic calculations are found to be drastically altered from the adiabatic and Born-Oppenheimer results.

Summary Background Bacterial meningitis is an important cause of morbidity and mortality in developing countries, but the duration of treatment is not well established. We aimed to compare the efficacy of 5 and 10 days of parenteral ceftriaxone for the treatment of bacterial meningitis in children. Methods We did a multicountry, double-blind, placebo-controlled, randomised equivalence study of 5 versus 10 days of treatment with ceftriaxone in children aged 2 months to 12 years with purulent meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae type B, or Neisseria meningitidis . Our study was done in ten paediatric referral hospitals in Bangladesh, Egypt, Malawi, Pakistan, and Vietnam. We randomly assigned children who were stable after 5 days of treatment, through site-balanced computer-generated allocation lists, to receive a further 5 days of ceftriaxone or placebo. Patients, their guardians, and staff were masked to study-group allocation. Our primary outcomes were bacteriological failure or relapse. Our analysis was per protocol. This study is registered with the International Standard Randomised Controlled Trial Number Register, number ISRCTN38717320. Findings We included 1004 of 1027 children randomly assigned to study groups in our analyses; 496 received treatment with ceftriaxone for 5 days, and 508 for 10 days. In the 5-day treatment group, two children (one infected with HIV) had a relapse; there were no relapses in the 10-day treatment group and there were no bacteriological failures in either study group. Side-effects of antibiotic treatment were minor and similar in both groups. Interpretation In children beyond the neonatal age-group with purulent meningitis caused by S pneumoniae, H influenzae type b, or N meningitidis who are stable by day 5 of ceftriaxone treatment, the antibiotic can be safely discontinued. Funding United States Agency for International Development.

To investigate the presence of any regional myocardial deformation abnormalities in Marfan syndrome (MFS) and determine the benefits of using advanced echocardiography compared to conventional techniques.Myocardial dysfunction in MFS may be caused by extracellular matrix remodeling thus, resulting in uniform reduced functionality. However, increased aortic stiffness may cause segmental ventricular abnormalities. Strain rate imaging (SRI) constitutes a validated technique to assess regional deformation in various clinical conditions. With this in mind, we aimed to investigate biventricular function in MFS using SRI.Forty-four MFS patients (mean age 30 ± 12 years, 26 men) and 49 controls without valvular disease were examined using SRI. Ejection fraction (EF) was calculated by the Simpson's biplane method. Biventricular deformation was assessed by measuring strain/strain rate. Strain values were divided by left ventricular (LV) end-diastolic volume to adjust LV deformation for geometry changes providing a strain index (SI). Aortic stiffness was evaluated using the β-stiffness index.EF (%) was reduced in MFS patients (59 ± 5 vs 72 ± 4, P0.001), whereas β-stiffness was increased (P0.001). LV radial and LV and right ventricular (RV) long-axis strain values (%) were reduced in the patient group (70 ± 17 vs 93 ± 10; 19 ± 2 vs 25 ± 2; 30 ± 9 vs 36 ± 8, respectively, P0.001). Strain rate measurements were also reduced (P0.001). In a multiple regression analysis, MFS diagnosis was negatively associated with LV SI (-0.262 [-0.306, -0.219], P0.001). β-Stiffness was negatively associated with SI obtained from the septum, inferior and anterior walls. ROC analyses demonstrated that SRI, when compared with conventional echocardiography, had higher sensitivity and specificity in predicting biventricular dysfunction in MFS.Our study showed a uniform reduction in biventricular deformation in MFS. These findings suggest that assessment of myocardial function using advanced echocardiographic techniques could be more accurate in MFS patient evaluation than conventional echocardiography alone.

We have theoretically studied the role of high-lying molecular electronic states on the high harmonic generation (HHG) in H(2)(+) within the framework of a time-independent Hermitian nonperturbative three-dimensional Floquet technique for continuous wave monochromatic lasers of intensities of 2.59 × 10(13), 4.0 × 10(13), and 5.6 × 10(13) W∕cm(2), and wavelengths of 1064, 532, and 355 nm. To evaluate the HHG spectra, the resonance Floquet quasienergy and the Fourier components of the Floquet state corresponding to the initial vibrational-rotational level v = 0, J = 0 have been computed by solving the time-independent close-coupled Schrödinger equation following the Floquet method. The calculations include seven molecular electronic states in the basis set expansion of the Floquet state. The electronic states considered, apart from the two lowest 1sσ(g) and 2pσ(u) states, are 2pπ(u), 2sσ(g), 3pσ(u), 3dσ(g), and 4fσ(u). All the concerned higher excited molecular electronic states asymptotically degenerate into the atomic state H(2 l) with l = 0, 1. The computations reveal signature of significant oscillations in the HHG spectra due to the interference effect of the higher molecular electronic states for all the considered laser intensities and wavelengths. We have attempted to explain, without invoking any ionization, the dynamics of HHG in H(2)(+) within the framework of electronic transitions due to the electric dipole moments and the nuclear motions on the field coupled ground, the first and the higher excited electronic states of this one-electron molecular ion.

Resonance-enhanced Raman scattering (RERS) from the ground X1Σg+(νg = 0, Jg) state of H2 via the excited intermediate C1Πu(ν = 0/1/2/3, Ji) state coupled non-adiabatically with the B1Σu+(νiB = 8/10/12/14, Ji) state was studied theoretically, applying second-order perturbation theory. The excitation and Raman spectra for the pure rotational, fundamental and higher overtones are presented. Effects of non-adiabatic coupling on the excitation profiles, scattered intensities and depolarization ratios were investigated. The intensities of excitation spectra and Raman lines for O-, Q- and S-branches were calculated using thermal Boltzmann factors for vibrational–rotational distribution at room temperature (300 K). The RERS cross-sections with adiabatic and non-adiabatic corrections are reported together with Born–Oppenheimer (BO) results where available, for comparison. The calculated RERS cross-sections including non-adiabatic effects were found to vary significantly from adiabatic or BO results.

The generalized resonance enhanced two‐photon dissociation (RETPD) cross sections of H2 are calculated for crossed and circular (same‐ and opposite‐sense) polarizations of the two‐photon fields using the reduced density operator formalism for the transitions X 1Σ+g(vg=0, Jg=0–4) →(ω1,e1)VUVB 1Σ+u (C 1Πu)[vi=0, 3, Ji =0(1)–3]→(ω2,e2)UV/visible [(EF+GK)1Σ+g+I 1Πg), Ef,Jf]. The wavelength (λ2) of the second photon is so chosen that ionization from the resonant B(C) state is energetically forbidden. The effects of polarizations on the wavelength and quantum number dependences of RETPD profiles have been studied. For vi=3 of both B and C states, a strong polarization dependence of RETPD cross sections is observed. The same‐ and opposite‐sense circular polarizations have about the same RETPD profiles for the B state except at the shape resonance positions due to the final I state quasibound level, while the profiles are quite different for the C state.

Discrete resonance Raman scattering (DRRS) from the ground X 1 Σ g + (v g =0, J g =0-2) state of H 2 via excited intermediate states B 1 Σ u + (v i =0-3, J i =0-3) and C i Π u (v i =0-3, J i =1-3) was studied theoretically, applying the reduced density operator formalism. The Raman spectra for the pure rotational, fundamental and higher overotones are presented. The intensities of the Raman lines for O, Q and S branches were calculated branches were calculated using thermal Boltzmann factors for vibrational-rotational distribution at room temperature (300 K). The calculated DRRS cross-sections are found to be many orders of magnitude largers than normal (non-resonance) Raman cross-sections for H 2 or continuum resonance Raman cross-sections for molecular ions such as HD +

The generalized resonance enhanced two‐photon dissociation (RETPD) cross sections of H2 are calculated for linear parallel polarizations of the two photon fields. The reduced density operator formalism is used to study the wavelength and quantum number dependences for the transitions X 1Σ+g (vg=0, Jg=0–4) →vuv B 1Σ+u (C 1Πu) [vi=0,3, Ji=0(1)–3] →uv/visible [(EF+GK)1 Σ+g +I 1Πg, Ef, Jf]. By resonant absorption of the first photon an aligned population in the intermediate B(C) is created which is then dissociated by the second photon. The wavelength is so chosen that ionization from the resonant intermediate state is energetically forbidden. The contribution of the EF state to the total cross section is found to be negligible. The relative contribution of the GK and I states varies sharply with wavelength of the second photon and the resonant intermediate state. For both B and C states, dissociation through the I state is more prominent over a narrow range of wavelengths far from the dissociation threshold ...

We have theoretically studied the population transfer in a five-level ${\mathrm{Li}}_{2}$ dimer by $(2+2)$-photon stimulated hyper-Raman nonadiabatic passage (STIHRNAP) from the initial ground level ${v}_{g}=0$, ${J}_{g}=0$ to the final rovibrational levels ${v}_{f}=1$ (2), ${J}_{f}=0,2$, of the ground electronic state $X\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{g}^{+}$ via the resonant intermediate levels ${v}_{i}=1$, ${J}_{i}=0,2$, of the excited electronic state $2\phantom{\rule{0.2em}{0ex}}^{1}\ensuremath{\Sigma}_{g}^{+}$. Linearly chirped pump and Stokes laser pulses with different chirp rates and without any initial detuning are applied simultaneously. Both the pulses are taken to have the same temporal shape, pulse width, and linear parallel polarizations. The density matrix method has been used to compute the populations of the levels. We have investigated in detail the population transfer for laser wavelengths (at time $t=0$) in the range of $992\char21{}1028\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ and (peak) intensities in the range of $1.5\ifmmode\times\else\texttimes\fi{}{10}^{10}\char21{}3.0\ifmmode\times\else\texttimes\fi{}{10}^{11}\phantom{\rule{0.3em}{0ex}}\mathrm{W}∕{\mathrm{cm}}^{2}$. The required pulse widths are of the order of $35\char21{}275\phantom{\rule{0.3em}{0ex}}\mathrm{ps}$ for maximum population inversion. We have controlled rotational branching in population transfer to the final rotational levels ${J}_{f}=0$ ($Q$ branch) and ${J}_{f}=2$ ($S$ branch) of the fundamental $({v}_{f}=1)$ and first overtone $({v}_{f}=2)$ transitions by judicious choice of laser parameters. We have applied a $(2+2)$-photon STIHRNAP process to a model multilevel molecular system $({\mathrm{Li}}_{2})$ and achieved almost complete population transfer from the initial ground to the final target rovibrational levels with chirped ir laser pulses.

We have performed a detailed calculation of the double-differential angular\char21{}kinetic-energy distribution of photofragments in above threshold dissociation (ATD) of $\mathrm{D}_{2}{}^{+}$ from initial vibrational-rotational levels ${v}_{i}=4,5$ and ${J}_{i}=0,1$ in an intense linearly polarized laser field of wavelength $400\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ and intensity $3\ifmmode\times\else\texttimes\fi{}{10}^{13}\phantom{\rule{0.3em}{0ex}}\mathrm{W}∕{\mathrm{cm}}^{2}$. The calculation used a time-independent close-coupling (CC) formalism with eight (ten) electronic states included in the basis-set expansion of the molecular wave function. The molecular electronic states included, apart from the two lowest $1s{\ensuremath{\sigma}}_{g}$ and $2p{\ensuremath{\sigma}}_{u}$ states, were $2p\ensuremath{\pi}_{u}{}^{\ifmmode\pm\else\textpm\fi{}}$, $2s{\ensuremath{\sigma}}_{g}$, $3p{\ensuremath{\sigma}}_{u}$, $3d{\ensuremath{\sigma}}_{g}$, $3d\ensuremath{\pi}_{g}{}^{\ifmmode\pm\else\textpm\fi{}}$, and $4f{\ensuremath{\sigma}}_{u}$. All the higher electronic states dissociate to the atomic state $\mathrm{D}(2\ensuremath{\ell})$. A sufficient number of photon absorption channels, $n=0\char21{}7$, and molecular rotational quantum numbers $J=0\char21{}11$ were taken into account to ensure the convergence of the multiphoton ATD probability. Altogether 198 coupled channels had to be considered in the calculation. The calculations reveal signatures of significant ejection of the photodissociation fragments away from the laser polarization direction due to the inclusion of the higher excited electronic states. The ratio of the photofragments perpendicular to and along the polarization axis shows good quantitative agreement with the experimental result. The angular distributions show considerable structures depending on the relative kinetic energies of the photofragments, and the fragments with different kinetic energies show peaks at different dissociation angles.

Left bundle branch block (LBBB) is associated with impaired left ventricular (LV) function and increased morbidity and mortality, especially in patients with structural heart diseases. The mechanisms are poorly understood.Subjects with isolated LBBB (n=20), right bundle branch block (RBBB, n=20), and controls (C, n=20) were studied with standard two-dimensional (2D), and color-encoded tissue-Doppler echocardiography (TDE). Inter- and intraventricular systolic and diastolic coordination were assessed from the TDE velocity profiles. LV function was assessed by 2D echocardiography, by TDE-derived peak systolic velocities, and the atrioventricular (AV) plane displacement.Subjects with LBBB had longer electromechanical delays and longer isovolumic relaxation times than did the C and RBBB groups (P0.001). For the LBBB subjects compared with the RBBB and C groups, ejection times were shorter, peak systolic velocities and AV plane displacements were lower, they had larger LV end-systolic volumes and lower LV ejection fraction (all P0.001), and the atrial contribution to A-V plane displacement was higher (P0.01). There were no differences in diastolic or filling times among the groups.In patients with LBBB, delayed regional electromechanical coupling and uncoupling leads to generalized intra- and interventricular asynchrony, thereby explaining the depressed regional and global LV functions. Assessment of the electromechanical coupling and uncoupling processes and their consequences on cardiac function in patients with BBB and structural heart diseases may be possible using TDE.

We have investigated the branching ratios and angular distributions of photofragments resulting from the two-frequency multiphoton dissociation of HD{sup +} from initial bound level v{sub i}=0,J{sub i}=0 induced by linearly polarized parallel laser fields of equal intensity of 1 TW/cm{sup 2}. Both the laser frequencies {omega}{sub 1} and {omega}{sub 2} are below the dissociation threshold with {omega}{sub 1}

We have theoretically investigated the role of high lying electronic states 2p{pi}{sub u} and 3d{sigma}{sub g} on multiphoton dissociation of D{sub 2}{sup +} from initial vibrational-rotational levels v{sub i}=4,5 and J{sub i}=0,1 by linearly polarized light with wavelength 400 nm and intensity 3x10{sup 13} W/cm{sup 2}. We have found that for initial level v{sub i}=4 and J{sub i}=1, a considerable number of photofragments is ejected perpendicular to the polarization direction of the laser field. It is shown that the perpendicular dissociation is due to the (net) four-photon absorption of the ground 1s{sigma}{sub g} state to the 3d{sigma}{sub g} state through the intermediate five-photon coupling of the 1s{sigma}{sub g} and 2p{pi}{sub u} states at intense laser field with high frequency. Our computed value of the emission of D{sup +} ions in the perpendicular direction to that in the parallel direction of the laser polarization reasonably agrees with the recent experimental result of Chin and co-workers at the same laser parameters [Phys. Rev. A 62, 042708 (2000)].

We have recalculated the photodissociation cross section of NaH as a function of photon wavelength for the $X{}^{1}\ensuremath{\sum}^{\ensuremath{\rightarrow}}B{}^{1}\ensuremath{\Pi}$ transition using the time-independent Fermi golden rule. We have made an attempt to clarify the discrepancy between a recent calculation where the time-dependent autocorrelation function was employed and an earlier one where the Fermi golden rule was used.

The effects of the nonmetabolizable amino acid alpha-aminoisobutyric acid (AIB) on insulin release were evaluated using beta cell-rich pancreatic islets from ob/ob mice. Both AIB and L-alanine promptly induced transient insulin release during column perifusion of islet cells. The secretory response was dependent on an elevated level of glucose and effectively suppressed by removal of Na+. The insulin release elicited by AIB fulfilled the criteria of a physiological event in being suppressed by clonidine or lowering of the temperature to 22 degrees C. AIB effectively promoted the increase in sodium (total as well as ionized cytoplasmic) obtained with ouabain blockage of the Na/K pump. When added to a medium containing 11 mM glucose, AIB altered cytoplasmic Ca2+ in terms of both an initial transitory rise and transformation of existing oscillations into a sustained elevation. It is concluded that amino acids can stimulate insulin release from mature beta cells by virtue of being cotransported with Na+.

Sodium was measured in β-cell-rich pancreatic islets of mice under steady state conditions or after 6 min of exposure to I mm ouabain. The islet content of sodium increased when 100,μ M tolbutamide or 1 μ M glipizide were added to an albumin-containing (1 mg ml −1 ) medium, but remained unaffected at 10-fold higher concentrations. Both sulphonylurea compounds promoted the uptake of Na + in the presence of ouabain. Whereas tolbutamide was stimulatory at 10μ M or above in a medium containing 10 mg ml − albumin, only 0.1 μ M was required in the absence of albumin. In the latter situation there was a reduction of the stimulatory action with increase of the tolbutamide concentration from 100 to 1000 μ M . The inhibitory component in the sulphonylurea action on the Na + uptake was particularly impressive with glipizide, maximal stimulation being reached at 10 μ M in the presence of 1 mg ml − albumin. Diazoxide (400 μ M ) modified the glipizide action on Na + uptake, making 1000 μ M stimulatory instead of 1 μ M . The latter concentration of glipizide became inhibitory after removal of K + . Glipizide stimulated the Na + uptake both at low and high concentrations in a medium deficient in Ca 2+ or when the cotransport of Na + , K + and Cl − was blocked by 20 μ M bumetanide. The observation that the sulphonylurea-induced islet accumulation of sodium is diminished at supramaximal concentrations reinforces existing arguments for additional effects of high concentrations of hypoglycemic sulphonylureas.

The increase of sodium in response to ouabain inhibition of the Na + /K + pump was measured in β-cell-rich pancreatic islets from ob/ob mice using integrating flame photometry. D -Glucose promoted the uptake of sodium when added at a concentration of 6 mM or above. The hypoglycemic sulfonylurea compound, tolbutamide, mimicked the action of D -glucose in stimulating the sodium uptake at concentrations of 10 μM or above. There was no stimulation beyond that obtained with 20 mM glucose during exposure to 100 μM tolbutamide. Other test substances also affected sodium uptake in a way reflecting known effects on insulin release. Accordingly, the sodium uptake was stimulated with glibenclamide, glipizide, HB 699 (4-[2-(5-chloro-2-methoxybenzamido)ethyl]benzoic acid) and high K + . Sulphonamides (sulfamethazole, sulfadiazine and sulfadoxine) had practically no effect when added at a concentration of 1 mM. Sodium uptake in response to glucose and tolbutamide was antagonized by 400 μM diazoxide or 4 μM tetrodotoxin. It is concluded that both glucose and hypoglycemic sulfonylureas stimulate Na + entry into the pancreatic β-cells, a process presumably involving depolarization.

Integrating flame photometry was used for measuring sodium in single pancreatic islets from ob/ob mice. Exposure to 100 μM carbachol resulted in a 25–40% increase in sodium without any effect on potassium during incubation with 0–5 mM glucose in media deficient or not in Ca 2+ This action of carbachol was abolished by 10 μM atropine or by raising the glucose concentration to 20 mM. A minor increase of the steady state content of sodium occurred in the presence of 200 μM ATP or 10 nM tetradecanoylphorbol 13-acetate (TPA). Carbachol differed from TPA in markedly stimulating sodium accumulation after ouabain inhibition of the Na/K pump. The results indicate that muscarinic receptor activation has opposite effects to glucose in inducing a rise of the islet content of sodium. It is suggested that the cholinergic control of the endocrine pancreas involves entry of Na + in addition to the Na + entry mediated by protein kinase C activation of Na + /H + countertransport.

We have theoretically investigated the population transfer from the initial ground rovibrational level v(g)=0, J(g)=0 to the final rovibrational levels v(f)=1,2, J(f)=0 of the ground electronic state X (1)Sigma(g) (+) via the resonant intermediate level v(i)=6, J(i)=0 of the excited electronic state EF (1)Sigma(g) (+) of H(2) molecule by (2+2)-photon stimulated hyper-Raman passage (STIHRP). The density matrix technique has been employed to evaluate the population transfer to the final target levels using linearly chirped pump and Stokes laser pulses with different chirp rates. Both the pulses are considered to have the same temporal shape, pulse width, and linear parallel polarizations. We have studied in detail the dependence of the population transfer on the set of laser parameters for pulse (peak) intensities in the ranges of 1.5 x 10(11)-1.0 x 10(12) and 1.0 x 10(12)-7.0 x 10(12) W/cm(2). The corresponding pulse widths (full width at half maximum) are of the order of 115-200 and 15-30 ps. We have found that the chirp rate parameters can be optimized to achieve almost complete population transfer from the ground (g) to the final (f) target levels. This, to our knowledge, is the first application of a (2+2)-photon STIHRP process with chirpings to a model molecular system (H(2)). The study demonstrates the suitability of the chirped (2+2)-photon STIHRP technique for selective and almost total inversion of vibrational population in a diatomic molecule.

Transition probabilities and cross sections for rotational transitions from the initial state j01=0, j02=1 have been calculated for an initial relative kinetic energy E0=0.025 eV. The semiclassical exponential approximation has been used. All possible single‐molecule and simultaneous transitions as well as intermultiplet transitions have been included with all energetically accessible states. These transitions are caused by the anisotropic short‐range, dispersive, inductive, and electrostatic interactions. The influence of pairs of resonating channels on the various inelastic transitions has been discussed. The limitations of the first order perturbation theory calculations are clearly brought out. The importance of various factors determining the relative magnitudes of the cross sections are shown.

The two-photon dissociation (TPD) cross section of HD+ by the 1s sigma g to 2p pi u electronic transition is calculated from the nu i=6, Ji=0 level of the ground 1s sigma g state in the wavelength range 1100-2100 AA. All possible bound and free intermediate states have been taken into account. Both the 1s sigma g to 2p pi u to 2p pi u and the 1s sigma g to 1s sigma g (bound) to 2p pi u channels are found to contribute significantly, though with opposite phases. The 1s sigma g to 1s sigma g (free) to 2p pi u channel in which one-photon continuum resonance TPD occurs makes a negligible contribution. The suitability of the radiation gauge form (A.p) of the interaction Hamiltonian is discussed from the point of view of failure of the electric field gauge form (E.d) in the calculation of free-free matrix elements. The cross sections are found to oscillate in the wavelength range considered.

The partial cross sections for photodissociation of HeH+ by both electronic (X1 Sigma + to A1 Sigma +) and vibrational (X1 Sigma + to X1 Sigma +) excitations have been studied by the first-order perturbation method. These cross sections sigma vj have been calculated for each of the vibrational levels from v=0 to 8 and for the rotational level j=1 of the ground electronic state. The maximum order of the photodissociation cross section by electronic excitation is 10-1 AA2 which is similar to that observed for H2+ (and its isotopes). For photodissociation by vibrational excitation, the cross sections are of the order of 10-3 AA2 for the v=8 and 7 levels and decrease gradually to 10-1 AA2 for v=0. The special features of the photodissociation cross sections due to the heteropolarity of HeH+ are discussed in detail by comparison with the results obtained for H2+ and HD+.