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Sediments delivered to the South Atlantic Ocean by the Orange River are fractionated and dispersed northwards and westwards by a vigorous longshore drift system and a number of ocean currents. Gravels are accreted to the coastline for a distance >300 km north from the Orange River mouth. Sands are transported alongshore for >700 km but are, in places along this transport path, returned onshore by coastal winds to form the main Namib Sand Sea and other smaller dune fields. Mud is more widely dispersed westwards, northwards and southwards, probably by slow-moving, ocean-scale currents into basins on the shelf and onto the continental shelf edge. This dispersal system, operating since at least Eocene times, is believed to have originated during a time when there was a Late Cretaceous–Early Cenozoic uplift of southern Africa, which resulted in: (1) intensification of the existing southerly wind system; (2) incision of the Orange River, which, coupled with a shift in climate, resulted in a coarsening of its sediment load delivered to the coast; (3) a broad, weakly subsiding or mildly uplifting inner continental shelf with little accommodation space for the sediment load of the incising Orange River.

Advanced high strength steels (AHSS) have been introduced and gradually adopted in vehicle structures as lightweight materials in the past years. Engineering performance of AHSS in many areas have shown that they are superior to the conventional steels. In this paper, we present the results from Charpy V-Notch impact tests on dual phase 590 (DP590) steel, which belongs to the family of AHSS. Tests were conducted at temperatures ranging from −120 °C (−184 °F) to 90 °C (194 °F). Specimens oriented in both L–T and T–L directions were tested. Due to its reduced thickness relative to the ASTM testing standards, specimens from a medium low carbon steel AISI-1018, having both standard and reduced thickness, were tested as well to justify the correction method for the DP590 data. The results show that the ductile–brittle transition temperature (DBTT) based on 20.4 J (15 ft-lb) absorbed energy is about −95 °C (−139 °F) for DP590 which is far below the 5 °C (41 °F) of the AISI-1018 steel. In addition, fracture toughness values of DP590 steel were obtained from correlation with the Charpy impact energy. It is shown that that the fracture toughness of DP590 is in the range of 160–200 MPa m 1/2 (146–182 ksi in. 1/2 ) in the upper shelf region, which includes the room temperature.

The Orange River, the principal conduit transporting diamonds from hinterland sources to the Namibian coast in post-Cretaceous times, is characterised by an extreme wave dominated delta that has given rise to a progression of coarse rudaceous littoral deposits preserved onshore for > 150 km north of the mouth. Under the long-lived, prevailing vigorous wave, wind and northward longshore drift regimes, the Orange River outfall has been reworked into, amongst others, a series of economically viable, diamondiferous Plio-Pleistocene onshore gravel beach deposits. These placers comprise spits and barrier beaches in the proximal reach within the palaeo-Orange River mouth that, after ca. 5 km northwards, merge into extensive but narrow linear beaches that, in turn after ca. 70 km, give way to pocket beaches. Gravel and diamond size decreases northwards away from the ancestral Orange River mouth. The linear and pocket beach types have considerably higher diamond content but lower average diamond stone size than the two proximal units that are characterised by low diamond grade but comparatively large average diamond size. Given the risk of delineating low grade alluvial diamond deposits accurately, we present here sedimentological reconstructions of the subtidal, intertidal and supra-tidal facies that constitute the spit and barrier beach sequences, based largely on face mapping of exploration trenches and open-cast, mine cuts, as well as the results of large tonnage, sampling campaigns. Diamond distribution is also linked convincingly to basic littoral processes that were operational within the palaeo-Orange River mouth during the complex transgression that gave rise to the + 30 m package in Plio-Pleistocene times. In both the spit and barrier beach settings, the intertidal deposits prove to be the most promising targets whereas the subtidal sediments are the least economic. The constant raking associated with coarse, cobble–boulder-sized gravel foreshore deposits in an energetic micro-tidal wave regime increased the average diamond stone size in the intertidal deposits to 1 to 2 carats per stone (cts/stn), but the lack of fixed trapsites (no competent footwall within the palaeo-Orange River mouth at that level) prohibited the accumulation of substantially enriched diamondiferous gravels. Consequently, grades of only 1.5 to 6 carats per 100 tons (cpht) are realised. The highest grades (2 to 6 cpht) are found in the landward-facing, intertidal beach deposits on the spits where gentle reworking in that sheltered environment had somewhat enriched and preserved the diamond content. Significantly, the low average stone size of ca. 0.5 cts/stn in this lower energy setting probably reflects that of the general diamond population available at that time. In contrast, the sand-rich subtidal deposits in the spit sequence return the lowest grades (0.1 to 0.5 cpht), similar to those in the slightly younger, subtidal transgressive boulder lags of the barrier beaches. However, the stone size in the spit subtidal sediments is also low (0.1 to 0.5 cts/stn) due to the highly mobile, fine-grained character of those deposits, whereas that in the subtidal transgressive lag is large (2 to 3 cts/stn) as a result of the local, semi-permanent turbulence associated with the boulder-sized clasts in these gravel sheets. Diamond distribution is therefore also influenced by littoral facies and associated beach types, in addition to the spatial and temporal parameters that have already been documented for the onshore marine placers of the southern Namibian coast.

Namibia's southwestern coast, the Sperrgebiet, hosts one of the world's largest gem diamond placer deposits consisting of fluvial, marine and desert deflation/aeolian placer types. To date, the richest onshore placer discovered in the Sperrgebiet comprises several, Plio-Pleistocene to Holocene, littoral marine packages distributed northwards from the Orange River mouth for some 120 km to Chameis Bay. In this zone, known as Mining Area No. 1 (MA1), these Quaternary marine deposits are floored predominantly by siliciclastic rocks of the Late Proterozoic Gariep Belt that have been bevelled into a number of marine-cut platforms during the different Quaternary high sea level stands (notably, at + 30 m, + 8 m, + 4 m and + 2 m). In many places, these bedrock platforms are extensively gullied and potholed, forming abundant fixed trapsites that promote diamond concentration in the Late Cainozoic littoral sediments. Some observations on the distribution, orientation and incision of bedrock gullies in MA1 are presented here. Three principal bedrock gully types, all of which constitute good diamond trapsites, have been identified in the bedrock footwall between the Orange River mouth northwards to Chameis Bay, a distance of some 120 km: (i) swash-parallel gullies in the southern, proximal sector where the bedrock s2 dips 45°W and the abrasive gravels are most abundant, thus overriding lithological and structural controls in the footwall; (ii) strike-parallel gullies in the central reach where the bedrock s2 dips between 80° and 85°W and the abrasive bedload is reduced, resistant lithological units promote the formation of such features along the orientation of the metsediments; and (iii) joint gullies in the northern, distal portion where the bedrock s2 dips 45–60° to the E and coarse abrasive bedload is virtually absent, the structural pattern in the bedrock is exploited by marine erosion. In these Late Cainozoic placers, diamond concentration is further linked to the depth of the gullies incised into the marine-cut platforms. Maximum incision is noted on the seaward margins of the marine-cut platforms where high-energy littoral processes, acting in a micro-tidal range of ca. 1.8 m under strong prevailing southerly wind and South Atlantic derived southwesterly swell regimes, promote marine erosion and deep gully formation. Therefore, the most favourable diamondiferous trapsites in the Late Cainozoic marine packages of the southwestern Sperrgebiet are those developed in deep bedrock gullies of either swash-parallel, strike-parallel or joint pattern origin on the seaward margins of marine-cut platforms that represent discrete high sea level stands during the Quaternary.

Three experiments were conducted to investigate the feasibility of using crystalline methionine and lysine as protein supplements for lactating Holstein cows. In the first experiment, Met (dl-methionine) and Lys (l-lysine-HCl) were added to diets used in continuous culture bioreactors to estimate optimal concentrations for use in subsequent in vivo experiments. The second experiment measured ruminal fermentation and nutrient flow to the small intestine when Met and Lys were top-dressed on diets fed to nonlactating cows. The third experiment measured lactation performance when Met and Lys were added to diets fed to late-lactation cows. Providing 0.29 and 2.27% of dry matter as Met and Lys, respectively, provided the largest improvement in fermentation in vitro and these concentrations were used in subsequent experiments. When Met and Lys were top-dressed on diets fed to nonlactating cows, no changes in total tract N digestion were observed. No changes in microbial protein production or ruminal fermentation were observed. Adding Met and Lys did not change production or efficiency of production of milk or milk components by late lactation cows. These data indicate that providing supplemental Met and Lys during late lactation does not significantly improve the protein status of the cow and therefore may not improve milk production.

Four nonlactating, mature, Holstein cows were fitted with ruminal cannula and used in a 4 x 4 Latin square-designed experiment to evaluate the impact of supplemental Zn and monensin on ruminal degradation of Lys and liquid 2-hydroxy-4-methylthiobutanoic acid (HMB). Cows were fed 4.54 kg (as fed) of alfalfa hay top-dressed with 4.54 kg (as fed) concentrate once daily. Concentrates were formulated to provide 0 or 500 mg/kg of Zn as ZnSO4 and 0 or 40 mg/kg of monensin in the total diet. Zinc supplementation provided approximately 22-fold greater dietary Zn than estimated by NRC requirements. On d 14 of each period, cows were dosed via the rumen cannula with 50 g of HMB and 100 g of Lys-HCl, and the concentrations of Lys and HMB were monitored every 0.5 h for 8 h. Supplemental Zn tended to decrease the proportion of acetate in ruminal fluid postfeeding and increased the proportion of propionate in ruminal fluid postfeeding. Supplemental Zn increased mean fluid passage rate from the rumen. Monensin decreased the proportion of acetate and increased the mean proportion of propionate in ruminal fluid, resulting in a decrease in the ratio of acetate to propionate. Monensin also increased the mean fluid passage rate from the rumen. Neither Zn nor monensin affected the apparent rate of ruminal disappearance of HMB or Lys. However, Zn and monensin interacted to alter the ruminal degradability of free Lys but not HMB. These data indicate that Zn and monensin may interact to alter ruminal degradability of free amino acids.

Rumen in vitro and in vivo experiments were conducted to evaluate the effect of rumen undegradable protein and soluble carbohydrates on rumen ammonia N release and lactation performance of Holstein cows. In the in vitro experiment, freeze-dried annual ryegrass (Lolium multiflorum, LAM) pasture was supplemented 1:1 with ground corn-based grain supplements containing expeller or solvent soybean meal with sucrose or lactose supplements at 0, 2.5, or 5% of dry matter (DM). The ammonia release rate was slower with expeller compared with solvent soybean meal-supplemented diets. Sucrose supplementation at the 5% level lowered rumen ammonia concentrations, but lactose-fortification of grain supplements was without effect. In the in vivo study, 32 multiparous Holstein cows were blocked according to milk yield and randomly assigned to corn-based grain supplements containing 1) solvent soybean meal, 2) solvent soybean meal + 5% sucrose supplement, 3) expeller soybean meal, or 4) expeller soybean meal + 5% sucrose supplement. Grain supplements and fresh annual ryegrass were component fed at approximately a 1:1 grain to forage ratio (DM basis). Forage DM intake was higher for cows receiving solvent soybean meal supplemented grain supplements than those receiving expeller soybean meal (12.2 +/- 2.1 vs. 11.4 +/- 2.2 kg/d), but total DM intake was similar for all diets (22.8 +/- 2.9 kg/d). Fat-corrected milk yield was similar for all diets averaging 37.5, 38.2, 39.1, and 37.6 kg/d for diets 1 to 4, respectively. Rumen fermentation, milk urea nitrogen, and body condition were unaffected by supplements; however, cows fed grain supplement 1 utilized dietary energy more efficiently than cows offered the other dietary treatments. High dietary crude protein concentrations may have limited lactation response to rumen undegradable protein and sugar.

A 2-yr study was conducted to determine the chemical composition and digestibility of silages made from forage sorghum, pearl millet, and tropical corn managed to optimize forage quality. Silages were ensiled in upright concrete silos lined with plastic and fed to heifers to determine in vivo apparent digestibility. Samples were collected before and after ensiling to determine ensiling characteristics and forage quality. After ensiling, tropical corn had the greatest dry matter (DM), the lowest crude protein, and the greatest water-soluble concentrations. Tropical corn silage had a pH of 3.96. The pH of forage sorghum silage was 4.09, and pearl millet had a pH of 4.50. Pearl millet had the lowest concentration of preensiled water-soluble carbohydrate, which likely caused the high pH in the silage. There were no differences among the forages in DM loss during ensiling in yr 2. Heifers fed pearl millet silage consumed more DM, but digestible DM intake was not different among the three groups of heifers. The results of this experiment indicate that pearl millet would be less desirable as a crop intended solely for silage production. Both forage sorghum and tropical corn could be grown specifically for ensiling based on DM digestibility. The decision on which crop to use should be based on factors such as production costs, forage yields, and local growing conditions rather than silage quality.

Purpose: To assess the frequency of retinopathy and vision loss in patients with insulin-dependent diabetes mellitus and their relations to potentially modifiable risk factors. Methods: The authors conducted a multicenter cross-sectional study of diabetic complications and their risk factors using standardized methods of assessment. The sample was comprised of 3250 insulin-dependent diabetic patients (1668 men, 1582 women) aged 15 to 60 years with mean (standard deviation) duration of diabetes of 14.7 (9.3) years from 31 European diabetes centers; 2991 of the patients were eligible for retinal photography. Visual acuity was measured using the Snellen chart. Retinopathy was evaluated by retinal photographs (two fields per eye) graded at a central facility. Glycated hemoglobin (HbA,c), cholesterol, triglyceride, fibrinogen, von Willebrand factor, and urinary albumin excretion rate were assessed at a single location. Results: Corrected visual acuity was greater than or equal to 1.0 in both eyes in 69.7% of patients and less than or equal to 0.1 in the best eye in 2.3%. Factors significantly related to vision loss were age, duration of diabetes, glycated hemoglobin (HbA 1c ), and level of retinopathy. Mild nonproliferative retinopathy was found in 25.8% of the patients, moderate-severe nonproliferative retinopathy in 9.8% of the patients, and proliferative retinopathy in 10.6% of the patients. After adjustment for age, duration of diabetes, HbA 1c , and albumin excretion rate, significant risk factors for moderate-severe nonproliferative retinopathy were blood pressure and triglyceride, and risk factors for proliferative retinopathy were triglyceride and fibrinogen. Conclusion: Vision loss is a common complication of patients with insulin-dependent diabetes, with diabetic retinopathy an important cause. Apart from poor glycemic control, several other potentially modifiable risk factors for retinopathy may be important, including elevated blood pressure, plasma triglyceride, and fibrinogen. In view of the possible barriers to the full implementation of strict glycemic control in this type of diabetes, additional strategies for the prevention and slowing of progression of retinopathy should be investigated, such as blood pressure and lipid lowering therapies.

The Homeb Silt Formation consists of eroded remnants of fine-grained alluvium that were deposited within the Kuiseb River valley in southern Namibia during the Late Pleistocene. In Holocene times the river deeply incised its valley fill leaving steep walled “castles” of relict alluvium—the Homeb Silts. This study is based on the 25 m thick type exposure of Homeb Silts at Homeb and describes flash-flood sediments that were colonised by successive generations of opportunistic arthropods. The stacked flood units each comprise a massive tabular siltstone bed overlain by a narrower interval of rapidly alternating sandstone and siltstone with claystone veneers. These flood units are interpreted as having accumulated under semi-arid climatic conditions by episodic back-flooding of the Kuiseb River into embayments and tributary mouths. Soon after deposition as the floodwaters subsided, the sediment was colonised by burrowing, sediment-ingesting organisms, mostly arthropods, that produced a Taenidium ichnofacies. After the floodwaters had drained, the exposed sediment was colonised by grasses and burrowed by terrestrial arthropods, probably ants and termites, resulting in an overprint of Termitichnus ichnofacies with associated pelletal chambers. Thirteen “horizons” of rhizocretions and root tubules occur toward the top of the succession and indicate a gradual reduction in the frequency of flooding. These immature calcic palaeosols suggest that the climate in the Central Namib Desert 20,000 years ago was semi-arid, being wetter and more seasonal than the hyperarid conditions that prevail today.

These variations from non standard current distributions may help explain why experimental data never exactly matches the theoretical models of RF plasma probes for any operating frequency near or below the natural plasma resonances. In fact if the PF-FDTD is correct, the non constant phase distribution delays the parallel resonance condition and down shifts the zero phase point below the frequency at which the dip in magnitude is seen. This has large ramifications as it has always been assumed that these two points directly correlate, as in traditional electrical circuits. This offsets in the apparent parallel resonance, from the upper hybrid, yields a false plasma density measurement for non calibrated RF plasma probes. Unfortunately to date no RF probe has had this offset factored into its measurements.

One hundred twenty-four cows (92 multiparous and 32 primiparous) were used to evaluate the effect of grain supplements containing high crude protein [(22.8% CP, 5.3% rumen undegradable protein (RUP), dry matter basis], moderate CP (16.6% CP, 6.1% RUP), and moderate CP with supplemental RUP (16.2% CP, 10.8% RUP) on lactation performance of Holstein cows rotationally grazing annual ryegrass-oat pastures. Supplemental protein was provided by solvent extracted soybean meal in the high CP and moderate CP supplements and as a corn gluten meal-blood meal mixture (2.8:1) in the moderate CP, high RUP supplement. Cows were blocked according to previous mature milk equivalent production and calving date (partum group;0 d in milk or postpartum group; 21 to 65 d in milk) and randomly assigned to dietary treatments. Grain was individually fed, at approximately a 1:3 grain to milk ratio, before a.m. and p.m milkings. The study was replicated during two grazing seasons that averaged 199 d. Cows had ad libitum access to bermudagrass hay while on pasture (dry matter intake ?1.3 kg/d). Protein supplementation had no effect on study long pasture dry matter (12.7 ± 1.0 kg/d) or total dry matter (23.9 ± 1.2 kg/d) consumption. Protein concentration did not affect actual milk yield of either calving group (high CP vs. moderate CP); however, postpartum group cows receiving high CP grain supplements maintained greater milk fat concentrations (3.34 vs. 3.11%), which led to higher fat-corrected milk (FCM) yields than control cows receiving moderate CP grain diets (30.3 vs. 28.9 kg/d). Crude protein concentration in milk of high CP-supplemented, postpartum group cows was also higher than moderate CP cows (3.42 vs. 3.27%). Additional RUP did not increase FCM yield above that generated by moderate CP grain diets for partum (34.3 vs. 32.9 kg/d) or postpartum-group cows (28.9 vs. 28.2 kg/d). Increasing CP concentration of grain supplement did not affect milk yield of Holstein cows grazing immature winter annual pastures. Supplementing additional RUP was without benefit, indicating that in this study energy deprivation may have been the major nutritional constraint for high-producing dairy cows grazing lush pastures.

We report the first demonstration of a 40 MHz four-port all-fiber frequency shifter operating at a wavelength of 1.55 /spl mu/m. The device has a high-conversion efficiency and low-drive power consumption, and is made from standard telecommunications fiber.

For a compactly supported function ϕ on ℝs we develop methods for computing the Fourier coefficients of transforms f(ΦT) of the symbol of ϕ. This problem arises in cardinal interpolation and in the construction of orthonormal wavelets. When the range of the symbol is a real interval, expansions of f in terms of orthogonal polynomials seem adequate. For complex valued ΦT, a Faber expansion of f is used.

The brains of six patients dying in diabetic ketoacidotic coma were examined histologically. Intravascular deposition of fibrin accompanied by ischaemic tissue damage was prominent in many vessels within the brain and other organs. Fibrinolytic and coagulation mechanisms were extensively studied in two patients before death and the results accorded with a major defect of these mechanisms. It is suggested that intravascular coagulation within the brain plays a major part in the production of coma in such patients and may well contribute to the mortality in this dangerous condition.

The Pliocene to Recent sand sea in the central part of the 2000 km long Namib Desert is underlain widely by sediments comprising the Tsondab Sandstone Formation (TSF) of Early to Middle Tertiary age. This formation is the earliest record of terrestrial sedimentation in the central Namib Desert and formerly was thought to consist of only eolian dune and sand sheet deposits of a desert origin. However, recent field investigations indicate that the TSF also includes deposits of ephemeral watercourses and pans (playas). These fluvial and playa sediments are associated intimately with the eolian dune and sand sheet deposits, as is likewise the case in the present, extreme-arid Namib Desert. Sedimentary structures and trace fossils in the TSF eolianites resemble those found in the modern sand sea. Furthermore, these eolianites were deposited under a dominant southerly and a subordinate easterly quadrant wind regime which is similar to the present-day circulation pattern in the Namib. Since the cold Benguela Current was established only in the Late Tertiary, the TSF represents a major, ancestral arid phase in the Namib tract that was controlled by an early anticyclonic wind regime and a geographic location on the rainshadow side of southern Africa.

beta-Thromboglobulin levels and platelet-aggregate ratios were determined in blood-samples from healthy control subjects and from diabetic patients with and without microangiopathic complications. Patients with diabetic microangiopathy had significantly elevated beta-thromboglobulin levels and also reversible platelet aggregates. In nine newly treated diabetics blood-glucose control was associated with a significant fall in plasma beta-thromboglobulin. Since beta-thromboglobulin is a platelet-specific protein the results indicate that diabetic microangiopathy is associated with evidence of platelet activation and that this may be influenced by the degree of biochemical control.

Platelets from diabetics with microvascular complications were shown to have lowered aggregation thresholds to ADP, epinephrine and collagen. They also produced more malonyl dialdehyde (MDA) than normal controls. In eight diabetic subjects, administration of dipyridamole (100mg tds)raised platelet aggregation thresholds and increased cyclic AMP levels, presumably as a result of inhibition of phosphodiesterase activity. It also caused a slight reduction of MDA production. This latter effect could be due to the rise in cyclic AMP, although we have found an apparently direct inhibitory effect to dipyridamole on MDA and thromboxane B2 production by intact platelets and platelet microsomes in vitro. On withdrawal of the drug, platelet cyclic AMP and MDA levels and aggregation thresholds returned toward pre-treatment levels. The administration of aspirin (120) plus dipyridamole markedly inhibited platelet aggregation, particularly in response to arachidonic acid and collagen and strongly inhibited MDA production. However, the rise in platelet cyclic AMP levels produced by dipyridamole alone was not present when aspirin and dipyridamole were given together, Aspirin may influence platelet cyclic AMP metabolism directly or by inhibiting prostacyclin formation. Thus, under appropriate conditions, basal platelet cyclic AMP may provide an index of PGI2 production in vivo.

Abnormal platelet function has been demonstrated in 20 patients with diabetic peripheral neuropathy. The results are compared to those obtained from 19 matched diabetic patients with no clinical evidence of complications and 20 matched normal control subjects. Platelets from patients with diabetic neuropathy showed an increased sensitivity to the aggregating agents adenosine diphosphate and adrenaline. Spontaneous platelet aggregation was demonstrated in both groups of diabetic patients.

We report a case of intraspinal subdural hematoma following trauma - a rare entity - with a review of the literature. The location of the hematoma in the cervical spine as described in this report is even more uncommon and was reported only once before. The pathophysiology of this entity is discussed, and the myelographic features are emphasized to facilitate the preoperative diagnosis.

Peripheral neuropathy is a serious complication of Diabetes Mellitus, The precise pathogenesis is unknown. Histological examination of biopsy material obtained from patients with diabetic neuropathy has revealed intravascular fibrin in vessels supplying the sural nerve in 10 out of 25 cases. This finding prompted us to study platelet function in this same group of patients.Blood samples were obtained from fifteen patients. After preparation of platelet-rich plasma, platelet aggregation was measured following the addition of various concentrations of ADP, collagen and adrenaline. The responses were assessed photoelectrically in a temperature-controlled, constantly stirred, non-glass system. In addition the samples were tested for spontaneous platelet aggregation.Spontaneous platelet aggregation was detected in one-third of samples studied, but in none of the controls. Enhanced ADP-induced aggregation was observed in 53% of samples and enhanced adrenaline-induced aggregation in 50%. Similar results were obtained with collagen.The data supports the view that enhanced platelet aggregation and intravascular thrombosis is of considerable importance in the pathogenesis of diabetic neuropathy.

A variety of platelet function tests have been performed in a series of IS diahetics (B male, 7 female). All had clinical evidence of peripheral neuropathy and some also had diabetic retinopathy. The following were measured a) Platelet survival as determined using 51Cr-labelled platelets;b) Plasma β-thromboglobulin;c) Platelet aggregate ratio;d) Malonyldialdehyde(MDA) production following the addition of thrombin or arachidonic acid to platelet-rich plasma.The tests showed widespread evidence of altered platelet function. Six patients had a reduced platelet survival time (No correlation was found between any of the tests in individual patients.These studies confirm that there is a widespread alteration in platelet function in diabetics with complications, but suggest that no single test may be used as an acceptable screening procedure.

Summary Many of the diabetic neuropathic syndromes are characterized by painful symptoms with a sensation of burning and associated with troublesome hyperaesthesia. It is important to distinguish between the acute and chronic forms of peripheral sensory neuropathy; while the former carries an excellent prognosis for symptomatic improvement within one year, the latter may cause persistent symptoms for many years. In contrast to the acute form, in which symptoms are particularly severe but abnormal neurological signs are minimal, patchy stocking and glove sensory loss together with peripheral small muscle wasting are often present in chronic sensorimotor neuropathy. Peripheral polyneuropathies are more common in patients with poor metabolic control, although recent evidence implicates blood glucose flux as a possible contributory factor to neuropathic pain. It is possible that blood glucose flux or altered peripheral blood flow leads to increased spontaneous activity in nociceptive afferent fibres which are present in the axonal sprouts that characterize small fibre neuropathy. In the diagnosis of the neuropathies, exclusion of other aetiological factors is of paramount importance as there is no specific diagnostic test for diabetic nerve damage. If there is no symptomatic improvement after a period of stable and optimal metabolic control together with simple analgesics, then the tricyclic drugs should be regarded as first line therapy. The rapid effect of these drugs suggests a peripheral rather than central mode of action.

Motor conduction velocity (M.C.V.) was measured in the median and lateral popliteal nerves in thirty-nine newly diagnosed diabetics at diagnosis, during the first six weeks of treatment, and again after six months' treatment. The mean M.C.V. in the group at diagnosis was comparable with values previously reported in patients with established diabetes. The mean change in the M.C.V. during treatment was in the direction of improvement and was shown to differ significantly from zero. The mean M.C.V. after diabetic control was established was greater than at diagnosis, although still well below that for non-diabetic subjects. It is suggested that this improvement in electrical function indicates improvement in nerve structure and that early effective control of the diabetic state would lead to a reduction in the incidence of serious nerve damage.

The hyperglycemic effects of clopamide 30 mg/day, clorexolone 25 mg/day and hydrochlorothiazide 25 mg/day were compared in a double-blind trial. The subjects were 18 established diabetics with mild hypertension or diabetic retinopathy. In the 15 patients not receiving insulin, clopamide and clorexolone caused a considerable elevation of the mean blood glucose, but hydrochlorothiazide at the dose used had no significant effect. Clopamide, clorexolone and, to a lesser extent, hydrochlorothiazide lowered the plasma potassium, blood pressure and body weight, and raised the blood urea. In the three insulin-dependent patients the changes in blood glucose were small and not statistically significant, although the changes in most other variables were similar to those described for the remainder of the group. The clinical and metabolic implications of these findings are discussed.

Dogs, pigs, rabbits, guinea pigs, and mice were exposed to nuclear detonations in two open underground partitioned shelters. The shelters were of similar construction, and each was exposed to separate detonations. Each inner chamber filled through its own 'orifice'; thus four separate pressure environments were obtained. An aerodynamic mound was placed over the escape hatch of each structure to determine its effect on the pressure-curve shape inside the chamber. In one test a sieve plate bolted across the top of the mound was evaluated. Wind protective baffles of solid plate and of heavy wire screen were installed in the shelters to compare primary and tertiary blast effects on dogs. One dog was severely injured from tertiary blast effects associated with a maximal dynamic pressure (Q) of 10.5 psi, and one was undamaged with a maximal Q of 2 psi. Primary blast effects resulting from peak overpressures of 30.3, 25.5, 9.5, and 4.1 psi were minimal. The mortality was 19 per cent of the mice exposed to a peak pressure of 30.3 psi and 5 and 3 per cent of the guinea pigs and mice exposed to a peak pressure of 25.5 psi. Many of the rabbits, guinea pigs, and mice sustained slight lung hemorrhages at maximum pressures of 25.5 and 30.3 psi. Eardrum perforation data for all species, except mice, were recorded. Following shot 2, thermal effects were noted. Animals of the groups saved for observation have died from ionizing-radiation effects.

Publisher Summary This chapter presents a study of borderline diabetics. In the study, it was found that treatment of a group of mildly hyperglycemic diabetic individuals with tolbutamide appeared to protect them against the manifestations of arterial disease over a five-year period as compared to a closely similar group treated, double-blind, with an indistinguishable placebo. The 248 borderline diabetics involved in this study were newly detected in the Bedford population survey of 1962 and were defined as having capillary blood sugar values between 120 and 199 mg/100 ml 2 h after 50 gm of oral glucose. Shortly after their detection, the 248 subjects were randomly allocated to tolbutamide or placebo treatment groups, each of which was further randomly divided into approximately equal-sized carbohydrate-restricted and placebo diet subgroups.

Publisher Summary This chapter discusses the polyol pathway in the neuropathy of early diabetes. The rise of osmotic pressure within the nerve as a result of the accumulation of sorbitol and fructose will not exceed 5% if the products are uniformly distributed in the aqueous portion of the nerve. If these compounds accumulate within the Schwann cell itself, however, osmotic damage may occur. Evidence suggests that the sorbitol pathway and the Schwann cell are closely associated. In an experiment described in the chapter, nerves of animals killed at 3, 6, and 10 days after induction of diabetes were analyzed. The results showed that the sorbitol pathway is activated very quickly when the blood sugar rises. It was found that after 3 days of hyperglycemia, the sorbitol levels were not significantly different from those found in animals with well-established diabetes. Control of blood sugar with insulin results in a significant reduction in the levels of sorbitol and fructose, this reduction being most evident in animals killed when normoglycemic. The levels in animals killed 40 h after the administration of insulin were well above those found in nondiabetics.

Mice were used to assess biologically the inside environment of two designs of heavy concrete personnel structures subjected to nuclear blast. A sample consisted of 20 mice; one sample was used in each of l2 structures. Aside from two samples placed in unrealistic locations, there was no immediate mortality. By D+20 days two mice from the close-in shelters and seven from those further out had died. (auth)