A description of the ab initio quantum chemistry package GAMESS is presented. Chemical systems containing atoms through radon can be treated with wave functions ranging from the simplest closed-shell case up to a general MCSCF case, permitting calculations at the necessary level of sophistication. Emphasis is given to novel features of the program. The parallelization strategy used in the RHF, ROHF, UHF, and GVB sections of the program is described, and detailed speecup results are given. Parallel calculations can be run on ordinary workstations as well as dedicated parallel machines. © John Wiley & Sons, Inc.

General atomic and molecular electronic structure system

The coupled‐cluster singles and doubles model (CCSD) is derived algebraically, presenting the full set of equations for a general reference function explicitly in spin–orbital form. The computational implementation of the CCSD model, which involves cubic and quartic terms, is discussed and results are reported and compared with full CI calculations for H2O and BeH2. We demonstrate that the CCSD exponential ansatz sums higher‐order correlation effects efficiently even for BeH2, near its transition state geometry where quasidegeneracy efforts are quite large, recovering 98% of the full CI correlation energy. For H2O, CCSD plus the fourth‐order triple excitation correction agrees with the full CI energy to 0.5 kcal/mol. Comparisons with low‐order models provide estimates of the effect of the higher‐order terms T1T2, T21T2, T31, and T41 on the correlation energy.

A full coupled‐cluster singles and doubles model: The inclusion of disconnected triples

Today, coupled-cluster theory offers the most accurate results among the practical ab initio electronic-structure theories applicable to moderate-sized molecules. Though it was originally proposed for problems in physics, it has seen its greatest development in chemistry, enabling an extensive range of applications to molecular structure, excited states, properties, and all kinds of spectroscopy. In this review, the essential aspects of the theory are explained and illustrated with informative numerical results.

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Coupled-cluster theory in quantum chemistry

The impact of ocular blood flow in glaucoma.

Over 7,000 peer reviewed articles have been published on electrochemical glucose assays and sensors over recent years. Their number makes a full review of the literature, or even of the most recent advances, impossible. Nevertheless, this chapter should acquaint the reader with the fundamentals of the electrochemistry of glucose and provide a perspective of the evolution of the electrochemical glucose assays and monitors helping diabetic people, who constitute about 5 % of the world’s population. Because of the large number of diabetic people, no assay is performed more frequently than that of glucose. Most of these assays are electrochemical. The reader interested also in nonelectrochemical assays used in, or proposed for, the management of diabetes is referred to a 2007 excellent review of Kondepati and Heise [1].

Electrochemical glucose sensors and their applications in diabetes management.

The objective of this study was to use a subcutaneous continuous glucose sensor to determine time differences in the dynamics of blood glucose and interstitial glucose. A total of 14 patients with type 1 diabetes each had two sensors (Medtronic/MiniMed CGMS) placed subcutaneously in the abdomen, acquiring data every 5 min. Blood glucose was sampled every 5 min for 8 h, and two liquid meals were given. A smoothing algorithm was applied to the blood glucose and interstitial glucose curves. The first derivatives of the glucose traces defined and quantified the timing of rises, peaks, falls, and nadirs. Altogether, 24 datasets were used for the analysis of time differences between interstitial and blood glucose and between sensors in each patient. Time differences between blood and interstitial glucose ranged from 4 to 10 min, with the interstitial glucose lagging behind blood glucose in 81% of cases (95% CIs 72.5 and 89.5%). The mean (+/-SD) difference between the two sensors in each patient was 6.7 +/- 5.1 min, representing random variation in sensor response. In conclusion, there is a time lag of interstitial glucose behind blood glucose, regardless of whether glycemia is rising or falling, but intersensor variability is considerable in this sensor system. Comparisons of interstitial and blood glucose kinetics must take statistical account of variability between sensors.

https://diabetes.diabetesjournals.org/content/diabetes/52/11/2790.full.pdf

Timing of changes in interstitial and venous blood glucose measured with a continuous subcutaneous glucose sensor.

Diagrammatic many‐body perturbation theory is formulated through third order and applied to LiH, BH, and HF with various sizes of two‐center Slater orbital basis sets. The most extensive calculations use 46 orbitals to recover 94, 95, and 97% of the experimental correlation energy for the three molecules, respectively, when the perturbation expansion is carried through third order with pair restrictions and including selections of higher‐order diagrams via denominator shifts. A detailed analysis of the ’’pair’’ correlation energies relative to SCF occupied orbitals is given, including both inter‐ and intrapair contributions for the different spin cases.

Many‐body perturbation theory applied to electron pair correlation energies. I. Closed‐shell first‐row diatomic hydrides

It is widely appreciated that impaired vascular circulation in the eye plays a significant role in the pathology of the retina, the optic nerve and the choroid. Capillary closure, microaneurysm formation, shunts, neovascularization and breakdown of the blood retinal barrier are non-specific responses to ischemia, congestion and thrombosis. Examples include diabetic retinopathy, where the microaneurysms and neovascularization reflect an underlying focal hypoxia and impaired ocular blood flow (Ashton 1953,1969; Davis 1968; Kohner et al. 1969; Gamer & Ashton 1972). Unfortunately, the identification of patients with impaired ocular blood flow, and the assessment of treatments aimed at improving the ocular circulation have been precluded by the absence of a suitable routine measurement of ocular blood flow. This situation is now changing with the recent development of non-invasive procedures for the assessment of ocular blood flow in the retina and ciliary choroidal networks. The non-invasive procedure of laser doppler velocimetry was developed for the measurement of retinal blood flow (Riva & Feke 1981; Riva et al. 1981, 1985). In this procedure the retinal blood flow is derived from the velocity (V) of red cells and the cross sectional area (A) of a given artery or vein; blood flow equals VA (mm3 min-1) for an individual vessel, and the total blood flow is the sum of flows in all the retinal arteries or veins. The mean velocity of blood was measured using a bidirectional laser doppler system and the vessel diameter assessed from monochromatic fundus photographs. In 8 healthy human eyes the average total volumetric flow in the retina was 34 p1 min-1 with a range of 18-44 pl min-I. The values of the retinal blood flow in man are similar to those determined in primate eyes by the radioactive labelled microsphere entrapment procedure, namely 25 If: 9 ~l min-l (Alm & Bill 1973). The non-invasive quantitative assessment of the ciliary choroidal blood flow is based on the analysis of the intraocular pressure (IOP) pulse. The flow of blood into the eye is pulsatile and causes a rhythmic fluctuation of the steady-state IOP. It is the magnitude and the form of the IOP pulse that is used to assess the pulsatile component of ocular blood flow. The high fidelity recording of the IOP that is essential for the evaluation of the pulsatile blood flow (PBF) is obtained with a pneumatic tonometric probe (Langham 1987). In order to quantitate, automate and rapidly analyze the IOP pulsations, the electronic signal from the probe is digitalized and fed into a modified IBM PS2/30 computer. Representative recordings of the IOP in eyes of 4 normal subjects are shown in Fig.1. Each IOP measurement is completed within 10 microseconds and the measurement repeated at intervals of 30 milliseconds, giving a total of 30 IOP readings during each cycle of the IOP. The average of all the individual IOP measurements is the steady state value, Goldmann (1954) recognized the problem of

Blood flow in the human eye.

A relationship has been derived between intraocular pressure and pulsatile blood flow in the eye. Measurements of intraocular pressure show a time variation that is associated with the pulsatile component of arterial pressure. Experimental results provide a means of transforming intraocular pressure changes into ocular volume changes. The eye is represented by a chamber with elastic walls, a pulsatile incoming flow of incompressible fluid (blood), and a steady outgoing flow of blood. Under these conditions, the rate of pulsatile blood flow through the eye can be approximated from the instantaneous intraocular pressure measurements. Data from a healthy human eye are used to illustrate the analysis.

Estimation of pulsatile ocular blood flow from intraocular pressure.

PurposeTo estimate the change in iris cross-sectional (CS) area with pupil dilation using anterior segment optical coherence tomography comparing eyes with angle closure (AC) to open angle glaucoma (OAG).MethodsSixty-five patients from the Wilmer Glaucoma service, 36 with definite or suspected OAG a

David M. Silver

Papers

Timing of changes in interstitial and venous blood glucose measured with a continuous subcutaneous glucose sensor.

Many‐body perturbation theory applied to electron pair correlation energies. I. Closed‐shell first‐row diatomic hydrides

Blood flow in the human eye.

Estimation of pulsatile ocular blood flow from intraocular pressure.

Iris cross-sectional area decreases with pupil dilation and its dynamic behavior is a risk factor in angle closure.