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It is shown how an asymptotic, boundary-layer method, developed specifically for application to facilitated mass transport, can also be applied to the corresponding problem of facilitated enthalpy transport. The method, which merely entails an implicit algebraic computation, is applied to the (hydrodynamic) film-theory model for heat transfer between a hot or cold wall and a reversibly dissociating gas mixture, 2N0 &2NO + 02, which has previously been treated by Brian and Bodman[l]. Good agreement is found with their approximate analytical formula over the parameter range of their computations. However, for more extreme states of dissociation and larger overall temperature differences, the present results differ from those given by their approximate formula, especially for the cooling (cold wall) problem. INTRODUCTION The conduction of heat in chemically reactive sys- tems is by no means a novel topic in the general area of diffusional transport phenomena. It has been the subject of several previous works, which are exemplified most notably by those of Hirshfelder[2], Brian and Reid[3], Brian and Bodman[l], Bodman et al. [4], Fan and Mason[5], and co-workers. One of the principal objectives of such studies has been to predict theoretically the reactive enhancement of steady-state heat trans- fer through a chemical mixture due to reversible thermal dissociation and recombination accom- panied by molecular diffusion of various chemical species. If, in such systems, say reacting gas mix- tures, the intrinsic rates of the chemical reactions are, in some appropriate sense, small compared to diffusional transport rates then one obtains the so-called ‘frozen’ (conductivity) regime, where reaction exerts a negligible influence on energy transport. At the opposite extreme, where reaction rates are in effect infinitely rapid, one obtains the (reaction) ‘equilibrium’ regime and, usually, max- imum enhancement of heat flux. In either of these asymptotic regimes one is generally able to perform fairly direct computations of the heat flux through a mixture from given trans- port and equilibrium properties; whereas, other- wise, one has to solve a set of non-linear differential equations, involving diffusion and reaction rates and governing spatial temperature and composition fields. While such boundary-value problems are in principle straightforward, albeit not analytically tractable, and actual numerical computation can be difficult and time-consuming, even with advanced computer-executed numerical schemes. These practical difficulties are traceable directly to a boundary layer structure that develops whenever reaction rates are moderately to highly rapid. This boundary-layer nature of the near- equilibrium regime was anticipated in the early works of Hirshfelder[2], but, up to the present, no general mathematical techniques have apparently been proposed to cope with the problem in this particular physical context. However, in very re- cent times there has been a good deal of effort devoted to the treatment of problems closely akin to the above in the related area of facilitated mass transport. Although there had been a previous long- standing interest in the reactive enhancement of mass transport, such problems have received re- newed attention because of their possible relevance to carrier-mediated biological transport in mem- branes and liquid films. Thus, Goddard

We used an isolated lung perfusion technique to examine the effect of alpha stimulation and alpha blockade on the pulmonary precapillary ( R a ) and postcapillary ( R v ) resistances of cardiogenic-shocked dogs. Five groups of dogs (10/group) were used: (1) controls, (2) cardiogenic-shock, (3) cardiogenic shock treated with a continuous infusion of norepinephrine to maintain the arterial blood pressure, (4) cardiogenic-shock treated with 1 mg/kg of phenoxybenzamine, and (5) cardiogenic shock in dogs previously made tolerant to lethal injections of epinephrine (1 mg/kg). All cardiogenic-shock dogs were studied 3 hr after closed-chest coronary artery microsphere embolization. Precapillary ( P a ) and postcapillary ( P v ) pressures were monitored, and the capillary pressures at constant lobe weight ( P c i ) were measured by the stopflow technique. Precapillary and postcapillary resistances were calculated using R a = ( P a - P ci )/ Q and R v = ( P ci - P v )/ Q . The ratio of postcapillary to precapillary resistance was calculated as an index of capillary pressure. Both the precapillary and postcapillary resistances were increased 3 hr after cardiogenic shock. This increase indicated that pulmonary vascular reactivity exists even without an intact nerve supply. The ratio of postcapillary to precapillary resistance was increased with cardiogenic shock which indicated an elevated capillary pressure. The postcapillary resistance was not significantly lowered with alpha stimulation, whereas both precapillary and postcapillary resistances were significantly lowered with alpha blockade. The ratio of postcapillary to precapillary resistance was increased with alpha stimulation and decreased with alpha blockade. An increase in the ratio of postcapillary to precapillary resistance is associated with an increase of capillary pressure and could lead to pulmonary congestion and edema on a mechanical basis. These data may explain the pulmonary congestion and poor survival in cardiogenic-shocked dogs treated with alpha stimulation and the increased survival in cardiogenic-shocked dogs treated with alpha blockade.

SUMMARY Several genetic models were considered to explain the distribution of qualitatively positive and negative children in 204 Caucasian families. A model which best describes the inheritance of the Lp antigenic expression involves a major genetic locus which distinguishes two overlapping continuously distributed modes of quantitative activity.

In order to evaluate the reliability and sensitivity of echocardiograms for detecting and quantitating pericardial effusion, 41 patients had echocardiograms on the day prior to cardiac operation. A fluid trap was used to aspirate the pericardium at operation. Thirty-nine of 41 patients had echocardiograms of diagnostic quality. In 25 patients, the echocardiogram was negative for pericardial effusion, with 0-16 ml identified at operation. In 13 patients, the echocardiogram was positive for pericardial effusion, with 15-775 ml aspirated at operation. A transition of patterns of relative posterior epicardial-pericardial movement was noted as the pericardial fluid volume increased. More than 15 ml was always found when a posterior echo-free space persisted throughout the cardiac cycle between a flat pericardium relative to the epicardium. In the presence of such a posterior echo-free space, a large anterior echo-free space made a moderately large pericardial effusion likely. In the absence of this diagnostic posterior echo-free space, an anterior echo-free space had no diagnostic significance, as it was found in 11 patients with less than 16 ml of pericardial effusion. A small posterior echo-free space persisting throughout the cardiac cycle between pericardial and epicardial echoes demonstrating virtually identical movements was found in two patients without any surgical evidence for pericardial effusion, but with evidence of adhesive fibrocalcific pericardial disease. A method of estimating pericardial volume is proposed, which uses the difference between the cubed diameters at the end-diastole of the pericardium and epicardium.

Part II of this review is concerned with the mathematical analysis of facilitated transport. An exposition is given of the most generally useful techniques for obtaining asymptotic or approximate solutions to one-dimensional carrier-mediated diffusion in membranes, involving multiple permeant and carrier species which undergo one or more chemical reactions. Primary emphasis is devoted to the limiting regimes of weakly-perturbed membranes (small driving forces) and slow or fast reactions (small or large Damkohler numbers). Many of the results appearing in the literature are unified and extended, and a systematic procedure for using these to estimate membrane performance is put forth. Finally, some areas for further work are identified.

The transport of a gas across a stationary hquld film containing reactive species 1s investigated for the purpose of determining gas permeablhtles or mass transfer coefficients m reacting solutions Under hnutmg condltlons when the reaction time constant far exceeds the dtiuslonal time constant, the flux of the transported gas follows Flck's law of dlffuslon Analytical series solution for the contnbutlon of the chemical reaction to the transport process 1s obtained usmg the technique of perturbation analysis, criteria for the validity of various terms m the series solution are presented The permeablhty of carbon dioxide m water and m 1N NaHCOrNa2C0, solution 1s estimated It 1s shown that a hleh degree of accuracy m the data 1s necessary for obtammg separate estimates of dlffuslvlty and sol&htyby this technique

DURING the school year 1963-1964, the DLos Angeles City School system was selected for a public health survey, "Medical Care of School Children: Factors Influencing Outcome of Referral from a School Health Program."' In this study, efforts were made to identify the factors that influenced referrals made for correction of defects found in school health examinations. It was found that children in low social rank areas were less likely to receive attention than were children in high social rank areas. Within low social rank areas, children were more likely to receive care if their parents "received more than one notification and were notified by more than one contact technique." Certain patterns of follow-up yielded a larger number of defects corrected than others. All effective referral patterns involved personal interaction between school personnel and parents. Based upon earlier findings, schools for this study were selected predominantly from lower social rank areas since Cauffman, Ph.D., F.A.P.H.A.; and Carl S. Shultz

The hindrance effect on the aqueous diffusion rate of solutes within membrane pores of molecular size has been accurately determined. Mica membranes, 3 to 5 micrometers thick, were prepared with uniform, straight pores from 90 to 600 angstroms in diameter. With these membranes a direct estimation was possible of the interaction between pore size and molecular diffusion rates. There were no uncertainties due to wide pore size distributions or nonuniform tortuous channels as in previously used model microporous materials such as dialysis tubing or gels. Aqueous diffusion rates through these mica membranes were measured for a series of compounds with molecular diameters from 5.2 to 43 angstroms and were corrected for "liquid film resistances" adjacent to the membrane-solution interface to obtain estimates of molecular diffusivities within the micropores of the membrane. Definite evidence is presented showing that, even when molecular size is a small fraction of pore size, diffusion rates decrease markedly. The apparent reduction in solute diffusivity in the microporous membrane can be quantitatively estimated by means of the Renkin equation for hindered diffusion.

Results with certain growth regulators or dormancy treatments indicate that sprouting and subsequent development of late blight on potato waste piles can be prevented if the cull potatoes are treated with dormancy treatments before or when the tubers are deposited on the cull piles.

Lp lipoproteins have been prepared by a mild method from the serum of a large number of individuals. Approximately 25% of the individuals tested showed the presence of a double Lp peak in analytical ultracentrifuge diagrams. These double peaks were designated Lp(a)-1 and Lp(a)-2 to distinguish them from the single Lp(a) peak. The mean viscosity-corrected sedimentation coefficient, S 1.004, 20 C and density of the single Lp(a) peak were 15.8±1.8s (n=32) and 1.076±0.01 g/ml, of the Lp(a)-1 peak were 13.5±1.1s (n=14) and 1.064±0.007 g/ml, and of the Lp(a)-2 peak were 16.8±1.7s (n=14) and 1.074±0.009 g/ml. Absorption tests using a double and single Lp preparation showed that both Lp peaks in the double variants possess Lp(a) specificity. Evidence is lacking as yet for individual specificities for either Lp(a)-1 or Lp(a)-2. Interand intra-individual heterogeneity among Lp lipoproteins is discussed.

The TLp(a) genetic variant of human serum 3-lipoprotein was detected by Berg,' using immunodiffusion with heteroimmune precipitating antiserum. Genetic studies by various investigators2' 3 indicated that the presence or absence of the Lp(a) factor was under the control of a single, autosomal gene and that the frequencies of the Lpa and Lp genes were approximately 0.19 and 0.81, respectively. The Lp system is independent4 of the Ag system.5 Rittner and Wichmann6 suggested that a complex of Lp genes may give rise to quantitative differences in the concentration of Lp-lipoprotein in different individuals. Using heteroimmune ant,isera which distinguish the Lp (a+) and Lp (a-) phenotypes, we have developed a method for isolation and partial purification of the Lp-lipoprotein by density gradient ultracentrifugation. This method and preliminary genetic and antigenic studies are presented in this report. Materials and Methods.-(a) Preparation oJ antisera: Method 1: Rabbits were injected intravenously every third day for four we'eks with 1 ml of Lp(a+) serum. Blood was collected 7 days after the last injection. Method 2: A rabbit was given a 1-ml intraperitoneal injection of partially purified Lp-lipoprotein in complete Freund's adjuvant, followed by two 1-ml injections of Lp-lipoprotein without adjuvant at 2-week intervals. The rabbit was bled 1 week after the last injection. Anti-a- and anti-:-lipoprotein sera were prepared by the same procedure. Commercial rabbit antisera specific for humana%lipoprotein and :-lipoprotein (Certified B ood Donor Se'rvice Inc., Woodbury, N. Y.) were also used. (b) Absorption techniques: Antisera against Lp(a+) serum were absorbed with 1.5 vol of Lp(a-) serum at 4?C for 24 hr. Antiserum against partially purified Lp-lipoprotein

Some selections ofS. tuberosum (S. andigenum) were found to possess a high level of resistance to mechanical and graft inoculation with viruses A and X. Nine of the selections proved highly resistant to inoculation with both viruses; graft inoculated plants developed no symptoms nor could either virus be recovered from them. Apparent immunity to graft inoculation with virus X was found in selections ofS. acaule, S. sucrense and 1 species hybrid. Four selections ofS. tuberosum and 1 selection ofS. maglia developed symptoms of virus X infection but were poor hosts for the virus as indicated by low titer upon subinoculating to indicator hosts. One selection ofS. cardiophyllum, 4 ofS. chacoense, 3 ofS. demissum, 2 ofS. hougasii, 1 ofS. phureja, 1 ofS. tuberosum, 8 ofS. stoloniferum and 2 species hybrids were apparently immune from mechanical inoculation with virus Y. Nine of these selections were apparently immune from graft inoculation with virus Y. Apparent immunity to graft inoculation with virus A was found in selections ofS. chacoense, S. demissum, S. hougasii, S. maglia, S. phureja, S. stoloniferum and 8 species hybrids. About half of the selections developed symptoms of virus A infection but the virus could not be recovered from them. No selection was found to be highly resistant to all three viruses.

Merrimack is a variety of potato bred by the United States Department of Agriculture and tested in New Hampshire. Maine, and elsewhere as part of the work of the National Potato-Breeding Program. Merrimack competed favorably with standard varieties in New Hampshire. It produced satisfactory yields of potatoes, with a relatively high dry-matter content from which excellent chips and french fries were made. In the Maine tests it did not yield as well as some of the standard varieties but in tests it was found to be highly resistant to, if not immune from, the common race of the late blight fungus in both vines and tubers. It is moderately resistant also to early blight, and was apparently fieldimmune from virus A and highly resistant to net necrosis. Its vines are very susceptible to leaf roll virus. Merrimack is not only highly resistant to ring rot but is the first variety released that is highly resistant to both late blight and ring rot. Its multiple-disease resistance should make it valuable, especially to growers who find it difficult to control late blight and ring rot in standard varieties.

The functional and immunologic profiles of pancreaticoduodenal segments after auto- and allotransplantation or denervation were compared. Elevated serum amylase levels were seen immediately after surgery as a result of ischemic damage but statistically significant changes from the preoperative state did not occur. Hyperglycemia was not observed in allografted dogs until just prior to death. Rejection of pancreatic allografts was characterized by a late increase in serum amylase which was not observed in denervated or autografted dogs. Pancreatic denervation with lymphatic interruption or heterotopic autotransplantation resulted in only a temporary exocrine hypofunction whereas allotransplantation was associated with more permanent acinar damage. Islet cell function remained adequate in all groups. Pancreatic venous drainage directly into the systemic or portal systems did not significantly influence fasting blood glucose levels, although higher serum insulin levels resulted from pancreatic venous drainage into the systemic circulation.

Procedures for the efficient and effective evaluation of potato seedling varieties for field immunity from potato virus A in the greenhouse were developed. Plants of seedling varieties selected from parents possessing field immunity are inarch-grafted with virus-A-infected plants of potato seedling 41956 to eliminate from further tests seedling varieties that show top necrosis and are, thus, field-immune from the virus. Subinoculations to plants ofSolanum demissum P. I. 175404 (local-lesion host) from mottled or symptomless plants about 35 days after grafting will detect, in 4 to 6 days, all seedling varieties susceptible to virus A. These susceptible seedling varieties are replanted, and when the plants are 1 to 2 inches tall they are infested with 25 to 50 virus-A-infective aphids for a 24-hour-period. After an incubation period of 30 to 35 days, diagnosis of infection is made by subinoculation from each plant to the indicator host. Seedling varieties not infected by aphid inoculation are considered field-immune from virus A.